[Federal Register Volume 79, Number 190 (Wednesday, October 1, 2014)]
[Proposed Rules]
[Pages 59363-59413]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2014-22776]
[[Page 59363]]
Vol. 79
Wednesday,
No. 190
October 1, 2014
Part II
Department of the Interior
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Fish and Wildlife Service
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50 CFR Part 17
Endangered and Threatened Wildlife and Plants; Proposed Endangered
Status for 21 Species and Proposed Threatened Status for 2 Species in
Guam and the Commonwealth of the Northern Mariana Islands; Proposed
Rule
Federal Register / Vol. 79 , No. 190 / Wednesday, October 1, 2014 /
Proposed Rules
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R1-ES-2014-0038: 4500030113]
RIN 1018-BA13
Endangered and Threatened Wildlife and Plants; Proposed
Endangered Status for 21 Species and Proposed Threatened Status for 2
Species in Guam and the Commonwealth of the Northern Mariana Islands
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service, propose to list 21
plant and animal species from the Mariana Islands (the U.S. Territory
of Guam and the U.S. Commonwealth of the Northern Mariana Islands) as
endangered species under the Endangered Species Act of 1973, as
amended. We also propose to list two plant species from the Mariana
Islands in the U.S. Territory of Guam and the U.S. Commonwealth of the
Northern Mariana Islands as threatened species under the Act. If we
finalize this rule as proposed, it would extend the Act's protections
to these 23 species. The effect of this regulation will be to add these
23 species to the Federal Lists of Endangered and Threatened Wildlife
and Plants.
DATES: We will accept comments received or postmarked on or before
December 1, 2014. Comments submitted electronically using the Federal
eRulemaking Portal (see ADDRESSES below) must be received by 11:59 p.m.
Eastern Time on the closing date. We must receive requests for public
hearings, in writing, at the address shown in FOR FURTHER INFORMATION
CONTACT by November 17, 2014.
ADDRESSES: You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal:
http://www.regulations.gov. In the Search box, enter FWS-R1-ES-
2014-0038, which is the docket number for this rulemaking. Then, in the
Search panel on the left side of the screen, under the Document Type
heading, click on the Proposed Rules link to locate this document. You
may submit a comment by clicking on ``Comment Now!''
(2) By Hard Copy: Submit by U.S. mail or hand-delivery to: Public
Comments Processing, Attn: FWS-R1-ES-2014-0038; Division of Policy and
Directives Management; U.S. Fish & Wildlife Headquarters, MS: BPHC,
5275 Leesburg Pike, Falls Church, VA 22041-3803.
We request that you send comments only by the methods described
above. We will post all comments on http://www.regulations.gov. This
generally means that we will post any personal information you provide
us (see Public Comments below for more information).
FOR FURTHER INFORMATION CONTACT: Loyal Mehrhoff, Field Supervisor,
Pacific Islands Fish and Wildlife Office, 300 Ala Moana Boulevard,
Honolulu, HI 96850; by telephone at 808-792-9400; or by facsimile at
808-792-9581. Persons who use a telecommunications device for the deaf
(TDD) may call the Federal Information Relay Service (FIRS) at 800-877-
8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Endangered Species Act of
1973, as amended (Act), if a species is determined to be an endangered
or threatened species throughout all or a significant portion of its
range, we, the U.S. Fish and Wildlife Service (FWS), are required to
promptly publish a proposal in the Federal Register and make a
determination on our proposal within 1 year. Critical habitat shall be
designated, to the maximum extent prudent and determinable, for any
species determined to be an endangered or threatened species under the
Act. Listing a species as an endangered or threatened species and
designations and revisions of critical habitat can only be completed by
issuing a rule. We will address designation of critical habitat for
these 23 species in a separate rule.
This rule will propose the listing of 23 species from the Mariana
Islands as endangered or threatened species. Twenty-one of these
species are proposed as endangered species (12 plants: Bulbophyllum
guamense (cebello halumtano), Dendrobium guamense (no common name
(NCN)), Eugenia bryanii (NCN), Hedyotis megalantha (paudedo), Heritiera
longipetiolata (ufa-halumtano), Maesa walkeri (NCN), Phyllanthus
saffordii (NCN), Psychotria malaspinae (aplokating-palaoan), Solanum
guamense (berenghenas halomtano), Nervilia jacksoniae (NCN), Tinospora
homosepala (NCN), and Tuberolabium guamense (NCN)); and 9 animals: the
Pacific sheath-tailed bat (Emballonura semicaudata rotensis; liyang),
Slevin's skink (Emoia slevini; guali'ek halomtano), the Mariana eight-
spot butterfly (Hypolimnas octocula mariannensis; NCN), the Mariana
wandering butterfly (Vagrans egistina; NCN), the Rota blue damselfly
(Ischnura luta; NCN), the fragile tree snail (Samoana fragilis;
akaleha), the Guam tree snail (Partula radiolata; akaleha), the humped
tree snail (Partula gibba; akaleha), and Langford's tree snail (Partula
langfordi; akaleha)). Two plant species (Cycas micronesica (fadang) and
Tabernaemontana rotensis (NCN)) are proposed for listing as threatened
species. Seven of these 23 species (1 bat, 2 butterflies, and 4 tree
snails) are candidate species for which we have on file sufficient
information on biological vulnerability and threats to support
preparation of a listing proposal, but for which development of a
listing regulation had been previously precluded by other higher
priority listing activities. This rule will reassess all available
information regarding status of and threats to these seven species.
Sixteen of the 23 species (14 plant species and 2 animal species
(Slevin's skink and Rota damselfly)) are Mariana Islands species for
which we have sufficient information on biological vulnerabilities and
threats to propose for listing as endangered or threatened, but which
have not been previously recognized as candidate species.
The basis for our action. Under the Act, we can determine that a
species is an endangered or threatened species based on any of five
factors: (A) The present or threatened destruction, modification, or
curtailment of its habitat or range; (B) Overutilization for
commercial, recreational, scientific, or educational purposes; (C)
Disease or predation; (D) The inadequacy of existing regulatory
mechanisms; or (E) Other natural or manmade factors affecting its
continued existence. As described in this document, these 23 species
are experiencing population-level impacts as the result of the
following current and ongoing threats:
Habitat loss and degradation due to development, military
activities, and urbanization; nonnative feral ungulates (hoofed
mammals, for example, deer, pigs, and water buffalo) and nonnative
plants; rats; snakes; wildfire; typhoons; water extraction, and climate
change.
Predation or herbivory by nonnative feral ungulates, rats,
snakes, monitor lizards, slugs, flatworms, ants, and wasps.
Inadequate existing regulatory mechanisms to prevent the
introduction and spread of nonnative plants and animals.
Ordnance and live-fire from military training,
recreational vehicles,
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and vulnerability to extinction due to small numbers of individuals and
populations.
As a consequence of these threats, we propose to list 2 of these
species as threatened species, and 21 of these species as endangered
species. We, therefore, propose adding these 23 Mariana Islands species
to the Federal Lists of Endangered and Threatened Wildlife and Plants.
We will seek peer review. We will seek comments from independent
specialists to ensure that our designation is based on scientifically
sound data, assumptions, and analyses. We will invite these peer
reviewers to comment on our listing proposal. Because we will consider
all comments and information received during the comment period, our
final determinations may differ from this proposal.
Information Requested
Public Comments
We intend that any final action resulting from this proposed rule
will be based on the best scientific and commercial data available and
be as accurate and as effective as possible. Therefore, we request
comments or information from the public, including landowners, land
managers, and residents of the U.S. Territory of Guam (Guam) and the
U.S. Commonwealth of the Northern Mariana Islands (CNMI), the
scientific community, industry, or any other interested parties
concerning this proposed rule. We particularly seek comments
concerning:
(1) The biology, range, and population trends of these species,
including:
(a) Biological or ecological requirements, including habitat
requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range including distribution patterns;
(d) Historical and current population levels, and current and
projected trends; and
(e) Past and ongoing conservation measures for these species, their
habitats, or both.
(2) Factors that may affect the continued existence of these
species, which may include habitat modification or destruction,
overutilization, disease, predation, the inadequacy of existing
regulatory mechanisms, or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning
any threats (or lack thereof) to these species and existing regulations
that may be addressing those threats.
(4) Additional information concerning the historical and current
status, range, distribution, and population size of these species,
including the locations of any additional populations of these species.
(5) Any information regarding the taxonomy of Tinospora homosepala,
with particular regard to the question of whether T. homosepala may be
the same species as the more common T. glabra, or is a variety of that
species.
Please include sufficient information with your submission (such as
scientific journal articles or other publications) to allow us to
verify any scientific or commercial information you include.
Please note that submissions merely stating support for or
opposition to the action under consideration without providing
supporting information, although noted, will not be considered in
making a determination, as section 4(b)(1)(A) of the Act directs that
determinations as to whether any species is a threatened or endangered
species must be made ``solely on the basis of the best scientific and
commercial data available.''
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in ADDRESSES. We request that you
send comments only by the methods described in ADDRESSES.
If you submit information via http://www.regulations.gov, your
entire submission--including any personal identifying information--will
be posted on the Web site. If your submission is made via a hardcopy
that includes personal identifying information, you may request at the
top of your document that we withhold this information from public
review. However, we cannot guarantee that we will be able to do so. We
will post all hardcopy submissions on http://www.regulations.gov.
Please include sufficient information with your comments to allow us to
verify any scientific or commercial information you include.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection on http://www.regulations.gov, or by
appointment, during normal business hours, at the U.S. Fish and
Wildlife Service, Pacific Islands Fish and Wildlife Office (see FOR
FURTHER INFORMATION CONTACT).
Public Hearing
Section 4(b)(5) of the Act provides for one or more public hearings
on this proposal, if requested. Requests must be received within 45
days after the date of publication of this proposed rule in the Federal
Register. Such requests must be sent to the address shown in FOR
FURTHER INFORMATION CONTACT. We will schedule public hearings on this
proposal, if any are requested, and announce the dates, times, and
places of those hearings, as well as how to obtain reasonable
accommodations, in the Federal Register and local newspapers at least
15 days before the hearing.
Peer Review
In accordance with our joint policy on peer review published in the
Federal Register on July 1, 1994 (59 FR 34270), we have sought the
expert opinions of 10 appropriate and independent specialists regarding
this proposed rule. The purpose of peer review is to ensure that our
listing determinations are based on scientifically sound data,
assumptions, and analyses. The peer reviewers have expertise about one
or more of the 23 species' biology, habitat, life-history needs, and
vulnerability to threats, which will inform our determination. We
invite comment from the peer reviewers during this public comment
period. A copy of our peer review plan is available for public review
at http://www.fws.gov/pacific/informationquality.
Previous Federal Actions
Seven of the 23 species proposed for listing as endangered species
are candidate species (77 FR 70103; November 22, 2013). Candidate
species are those taxa for which the U.S. Fish and Wildlife Service
(Service) has sufficient information on their biological status and
threats to propose them for listing under the Act, but for which the
development of a listing regulation has been precluded to date by other
higher priority listing activities. The current candidate species
addressed in this proposed listing rule include the following seven
animal species: the Pacific sheath-tailed bat (Emballonura semicaudata
rotensis), the Mariana eight-spot butterfly (Hypolimnas octocula
marianensis), the Mariana wandering butterfly (Vagrans egistina), the
fragile tree snail (Samoana fragilis), the Guam tree snail (Partula
radiolata), the humped tree snail (Partula gibba), and Langford's tree
snail (Partula langfordi). The candidate status of these species was
most recently reaffirmed in the November 22, 2013, Review of Native
Species that are Candidates for Listing as Endangered or Threatened
(CNOR) (77 FR 70103).
On May 4, 2004, the Center for Biological Diversity petitioned the
Secretary of the Interior to list 225 species of plants and animals,
including the 7 candidate species listed above, as endangered or
threatened under the provisions of the Act. Since then, we
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have published our annual findings on the May 4, 2004, petition
(including our findings on the seven candidate species listed above) in
the CNORs dated May 11, 2005 (70 FR 24870), September 12, 2006 (71 FR
53756), December 6, 2007 (72 FR 69034), December 10, 2008 (73 FR
75176), November 9, 2009 (74 FR 57804), November 10, 2010 (75 FR
69222), October 26, 2011 (76 FR 66370), November 21, 2012 (77 FR
69994), and November 22, 2013 (77 FR 70103). This proposed rule
constitutes a further response to the 2004 petition.
In addition to the 7 candidate species, we are proposing to list 16
additional species that occur in the Mariana Islands as endangered or
threatened species, including 14 plants (Bulbophyllum guamense, Cycas
micronesica, Dendrobium guamense, Eugenia bryanii, Hedyotis megalantha,
Heritiera longipetiolata, Maesa walkeri, Nervilia jacksoniae,
Phyllanthus saffordii, Psychotria malaspinae, Solanum guamense,
Tabernaemontana rotensis, Tinospora homosepala, and Tuberolabium
guamense) and 2 animals (Slevin's skink (Emoia slevini) and the Rota
blue damselfly (Ischnura luta)). Three of these plant species,
Heritiera longipetiolata, Maesa walkeri, and Psychotria malaspinae,
have been identified as the ``rarest of the rare'' Mariana plant
species and in need of immediate conservation under the multiagency
(Federal and Territorial) Guam Plant Extinction Prevention Program
(GPEPP). The goal of GPEPP is to prevent the extinction of plant
species that have fewer than 200 individuals remaining in the wild on
the island of Guam (GPEPP 2014, in litt.). We believe these 14 plants
and 2 animal species warrant listing under the Act for the reasons
discussed in the ``Summary of Factors Affecting the Species'' section
(below). Because these 16 species occur within 2 of the same ecosystems
as the 7 candidate species, and share common threats with them, we have
included them in this proposed rule to provide them with protection
under the Act in an expeditious manner.
We will be publishing a proposal to address critical habitat for
the 23 Mariana Islands species under the Act in the near future.
Background
Mariana Islands Species Addressed in this Proposed Rule
Table 1 below provides the scientific name, common name, listing
status, and range (islands on which the species is found) for the 23
Mariana Islands species that are addressed in this proposed rule.
Table 1--The 23 Species Addressed in This Proposed Rule
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Scientific name Common name(s) Listing status Range
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Plants
Bulbophyllum guamense................ cebello halumtano\Ch\.. Proposed-Endangered.... Guam, Rota, Saipan (H),
Pagan (H).
Cycas micronesica.................... fadang\Ch\............. Proposed-Threatened.... Guam, Rota, Pagan,
Palau,* Yap.*
Dendrobium guamense.................. NCN.................... Proposed-Endangered.... Guam, Rota, Tinian (H),
Saipan (H).
Eugenia bryanii...................... NCN.................... Proposed-Endangered.... Guam.
Hedyotis megalantha.................. paudedo\Ch\............ Proposed-Endangered.... Guam.
Heritiera longipetiolata............. ufa-halomtano\Ch\...... Proposed-Endangered.... Guam, Saipan, Tinian,
Rota (H).
Maesa walkeri........................ NCN.................... Proposed-Endangered.... Guam, Rota.
Nervilia jacksoniae.................. NCN.................... Proposed-Endangered.... Guam, Rota.
Phyllanthus saffordii................ NCN.................... Proposed-Endangered.... Guam.
Psychotria malaspinae................ aplokating-palaoan\Ch\. Proposed-Endangered.... Guam.
Solanum guamense..................... berenghenas Proposed-Endangered.... Guam, Rota (H), Tinian
halomtano\Ch\. (H), Saipan (H),
Asuncion (H), Guguan
(H), Maug (H).
Tabernaemontana rotensis............. NCN.................... Proposed-Threatened.... Guam, Rota.
Tinospora homosepala................. NCN.................... Proposed-Endangered.... Guam.
Tuberolabium guamense................ NCN.................... Proposed-Endangered.... Guam, Rota, Aguiguan
(H), Tinian (H).
Animals
Emballonura semicaudata rotensis..... Pacific sheath-tailed Proposed-Endangered (C) Aguiguan, Guam (H),
bat, liyang\Ch\, Rota (H), Tinian (H),
payesyes\Ca\, pai Saipan (H), Anatahan
scheei\CI\. (H*), Maug (H*).
Emoia slevini........................ Slevin's skink, Proposed-Endangered.... Guam (Cocos Island),
Marianas Emoia, Alamagan, Asuncion,
guali'ek halom Guguan, Pagan,
tano\Ch\. Sarigan.
Hypolimnas octocula mariannensis..... Mariana eight-spot Proposed-Endangered (C) Guam, Saipan (H).
butterfly.
Vagrans egistina..................... Mariana wandering Proposed-Endangered (C) Rota, Guam (H).
butterfly.
Ischnura luta........................ Rota blue damselfly.... Proposed-Endangered.... Rota.
Partula gibba........................ humped tree snail, Proposed-Endangered (C) Guam, Rota, Aguiguan,
akaleha'\Ch\. Alamagan, Pagan,
Sarigan, Saipan,
Tinian (H), Anatahan
(H).
Partula langfordi.................... Langford's tree snail, Proposed-Endangered (C) Aguiguan.
akaleha'\Ch\.
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Partula radiolata.................... Guam tree snail,....... Proposed-Endangered (C) Guam.
akaleha'\Ch\...........
Samoana fragilis..................... fragile tree snail, Proposed-Endangered (C) Guam, Rota.
akaleha'\Ch\.
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NCN = no common name.
(C) = Candidate Species.
H) = historical occurrence.
(H*) = possible historical occurrence.
Ch = Chamorro name.
Ca = Carolinian name.
* = range outside of the Mariana Islands.
The Mariana Islands
Geography
The Mariana Islands is a longitudinallyarranged archipelago
consisting of 15 main islands and various smaller islets located in
western Micronesia between latitudes 21[deg] and 13[deg] N and
longitudes 144[deg] and 146[deg] E. The Mariana Islands vary in age,
between 5 million years old in the north and 50 million years old in
the south. The archipelago was formed by the collision of the Pacific
and Philippine tectonic plates at the Mariana Trench, which resulted in
volcanic activity that built up a chain of mountains protruding from
the sea floor (see Figure 1) (Raulerson and Rinehart 1992, p. 3;
Scripps Institution of Oceanography (SIO) 2014, in litt.). Scientists
biogeographically separate the Mariana Islands into the ``northern''
and ``southern'' islands based on geological time of formation and
associated substratum (Fosberg et al. 1975, pp. 1-5; Mueller-Dombois
and Fosberg 1998, p. 241). The primarily volcanic northern islands
include Farallon de Medinilla, Anatahan, Sarigan, Guguan, Alamagan,
Pagan, Agrihan, Asuncion, Maug, and Uracas, while the limestone and
volcanic southern islands include Guam, Rota, Aguiguan, Tinian, and
Saipan. The northern islands of Anatahan, Guguan, Alamagan, Asuncion,
Pagan, and Uracas are still volcanically active. Only the southern
islands of Guam, Cocos Island, Rota, Tinian, and Saipan are regularly
inhabited by humans; all of the other Mariana Islands are considered
uninhabited, although some (e.g., Aguiguan, Pagan) may be visited on
occasion.
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Geology
The substratum of the younger northern islands is of volcanic
origin, while the substratum of the older southern islands is coral
limestone (Mueller-Dombois and Fosberg 1998, p. 241). The limestone
substratum of the southern islands is composed of ancient coral reef
limestone that developed as the islands rose from the ocean floor and
eventually above sea level (Berger et al. 2005, p. 9). The northern
islands contain very little limestone substratum
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due to their young age and because many of them (Uracas, Pagan,
Asuncion, Guguan and Anatahan) remain volcanically active (Ohba 1994,
p. 14; U.S. Geological Survey (USGS) 2006, in litt.). The northern
islands are composed of black basalts and are typically cone-shaped
volcanoes with steep slopes, many of which have eroded into steep
ravines often widened by erosion (Ohba 1994, p. 14). Areas of exposed
weathered volcanic substratum can be found on the southern islands,
particularly on the southern half of Guam, in strong contrast to the
predominant karst limestone composition of the northern half of the
island (Mueller-Dombois and Fosberg 1998, p. 241).
Vegetation
Both the intentional and inadvertent introduction of alien plant
and animal species has contributed to the reduction in range of native
vegetation throughout the Mariana Islands (throughout this rule, the
terms ``alien,'' ``feral,'' ``nonnative,'' and ``introduced'' all refer
to species that are not naturally native to the Mariana Islands).
Currently, most of the extant native vegetation on the islands persists
on rugged karst or steep limestone slopes and precipitous cliffs,
ridgelines, valleys, and other regions where unsuitable topography
prevents urbanization and agricultural development, or where
inaccessibility limits encroachment by nonnative plants and grazing by
feral ungulates (Amidon 2000, p. 5; Berger et al. 2005, pp. 37, 44-45).
Hydrology
There are no year-round surface water sources in the northern
islands, with the exception of two small lakes on the island of Pagan.
The southern islands, in contrast, exhibit multiple year-round surface
water sources including wetlands and streams on Saipan, two perennial
streams and two springs on Rota, a small wetland on Tinian, and several
wetlands, rivers, and streams on the volcanic portions of southern
Guam, particularly in the Tolofofo River region (CNMI Statewide
Assessment and Resource Strategy Council (CNMI-SWARS) 2010, pp. 9-10,
30, 32; Mueller-Dombois and Fosberg 1998, pp. 248, 254, 260, 266, 269;
SIO 2014, in litt.).
Climate
Their relatively low elevation above sea level (the highest point
in the chain is Mt. Agrihan on Agrihan at 3,166 ft (965 m)), juxtaposed
with their close proximity to the equator, insulate the Mariana Islands
from seasonal variation in weather and climate. The entire archipelago
is defined as the ``tropical rainforest climate'' according to the
Koeppen climate classification (Ohba 1994, p. 16); however, there are
very few year-round meteorological weather stations in the Mariana
Islands, resulting in limited available meteorological data. Additional
data has been collected from Iwo-Jima from which patterns are
collectively extrapolated across the Mariana archipelago (Ohba 1994,
pp. 15-16).
The Mariana archipelago exhibits two distinct seasons, a notably
wetter season from July through October, and a drier season from
November through June, with April characteristically being the driest
month out of the year (Ohba 1994, p. 16; Mueller-Dombois and Fosberg
1998, p. 241). Precipitation averages 96 in (218 cm) per year,
dependent in part upon elevation. Some of the tallest peaks across the
islands experience frequent cloud cover, particularly the northern
island summits of Anatahan, Alamagan, Pagan, and Sarigan (Dahl 1980,
pp. 22, 64; Ohba 1994, pp. 18, 41, 48). Stone (1970, p. 12) observed
the southern Mariana Islands (from Anatahan southward) to be warmer
than the northern islands.
The Mariana Islands receive relatively constant trade winds with a
weak westerly monsoon influence in summer months (Mueller-Dombois and
Fosberg 1998, p. 241). Storms and typhoons originating from the
southeast and east occur frequently with an average of one typhoon per
year affecting the Mariana Islands (Mueller-Dombois and Fosberg 1998,
p. 241).
Biogeography
In general, the younger, northern islands, particularly the five
active volcanic islands (Uracas, Pagan, Asuncion, Guguan, and
Anatahan), support fewer species and ecosystem types than the southern
islands, due primarily to factors including age, time since last
eruption, island size, and highest point of elevation (Ohba 1994, pp.
15-18; Mueller-Dombois and Fosberg 1998, p. 241). Historically,
volcanic eruptions have proved very disruptive to the ecology of the
more northern Mariana Islands when they occur (USGS 2006, in litt.;
Zoology Unlimited, LLC (Limited Liability Company) 2013, pp. 9-11). For
example, in May 2003, the island of Anatahan experienced a powerful and
explosive eruption that destroyed 80 to 90 percent of the island's
forest cover and was believed to have caused the extirpation of the
Mariana fruit bat (Pteropus mariannus mariannus) and Micronesian
megapode (Megapodius laperouse laperouse) (Zoology Unlimited, LLC.
2013, pp. 10-11). Fortunately, these two species have been observed on
Anatahan in recent years, albeit in low numbers (Zoology Unlimited,
LLC. 2013, pp. 10-11).
The cumulative literature portrays Guam and Rota, in the southern
part of the archipelago, as the most species-rich of the Mariana
Islands. Mueller-Dombois and Fosberg (1998, p. 243) conducted one of
the most comprehensive vegetation analyses of the Mariana Islands
(building upon their previous works and those of Stone (1970, 659 pp.),
Ohba (1994, p. 18), and many others) and observed that, although the
primary substratum differs between the northern and southern islands
(e.g., volcanic versus limestone, respectively), the physical nature of
the substratum may be of equal or more importance than the chemical
nature in determining vegetation patterns. For example, some areas
covered by rough lava flows found on the northern islands exhibit
convergent forest type compared to forests found on the karst limestone
in the southern islands (Mueller-Dombois and Fosberg 1998, pp. 243-
245). Additionally, grassland (i.e., savanna) species in the northern
islands overlap with species found in the southern islands grasslands,
although species richness is greater on the southern islands (Mueller-
Dombois and Fosberg 1998, p. 241). The northern islands are
predominantly primary grasslands (colonized relatively recently after
volcanic activity) with areas of secondary forest. Conversely, the
southern islands are predominantly primary and secondary forests with
secondary grasslands, a situation that likely arose from grassland
expansion through agricultural burning and clearing (Mueller-Dombois
and Fosberg 1998, p. 241).
Micronesia, together with Polynesia, is described as the Polynesia-
Micronesia Hotspot, meaning that these island groups contain an
exceptional concentration of endemic (found nowhere else in the world)
species, and are currently experiencing exceptional habitat loss (Myers
et al. 2000, pp. 853-855).
Pre-Historical Human Impact
Archaeological evidence indicates that the Mariana Islands had been
settled approximately 2,000 B.C. by the pre-contact Chamorro people,
who migrated from Southeast Asia (SIO 2014, in litt.). The Chamorro
people introduced to the islands a variety of food plants including
rice, breadfruit, sugar cane, bananas, coconuts, and taro (Stone 1970,
pp. 182, 200). The exact
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extent to which these early settlers modified the landscape is unknown;
however, it is believed to be not insignificant (Fosberg 1960, pp. 36,
42-43). These environmental impacts may parallel those documented in
the Hawaiian Islands by early Hawaiian settlers; however, early
Chamorro impacts in the Mariana Islands are not as well documented.
The Chamorro established their largest settlements in the southern
islands including Guam, Rota, and Saipan (Russell 1998, p. 87).
However, multiple smaller settlements existed in the northern islands
and these were likely dependent in part on the larger communities in
the relatively resource-rich southern islands (Russell 1998, p. 84).
Researchers estimate that 100,000 to 150,000 Chamorro may have
inhabited these islands, a number that declined to below 5,000
individuals just a few hundred years after European contact due to
introduced diseases and other factors (SIO 2014, in litt.).
Historical and Ongoing Human Impacts
After the initial Chamorro modifications for agriculture and
villages, the flora and fauna on the Mariana Islands continued to
undergo alterations due not only to ongoing volcanic activity in the
northern islands, but also to land use activities and nonnative species
introduced by European colonialists. The arrival of the Spanish in 1591
further imposed degradation of the ecosystems of the Mariana Islands
with the introduction of numerous nonnative animals and plants. The
Spanish occupied the Mariana Islands for nearly 300 years (SIO 2014, in
litt.). In 1899, Spain sold the Mariana Islands to Germany, with the
exception of Guam, which was ceded to the United States as a result of
the Spanish-American war (SIO 2012, in litt.; Encyclopedia Britannica
2014, in litt.).
The German administration altered the forest ecosystem on Rota,
Saipan, and Tinian, and on some of the northern islands, by means of
Cocos nucifera (coconut) farming, which was encouraged for the
production of copra (the dried fleshy part of a coconut used to make
coconut oil) (Russell 1998, pp. 94-95). Upon the start of World War I,
the Japanese quickly took over German occupied islands and accelerated
the alteration of the landscape by clearing large areas of native
forest on Rota, Saipan, and Tinian for growing Saccharum officinarum
(sugarcane) and building associated refineries and for planting Acacia
confusa (sosugi) to provide fuel wood (CNMI-SWARS 2010, pp. 6-7). The
Japanese drastically altered the islands of Rota, Saipan, and Tinian,
leaving little native forest. Military activities during World War II
further altered the landscape on Saipan and Tinian. Rota was a notable
exception, left relatively untouched (CNMI-SWARS 2010, p. 7). Japan
also occupied Guam at the onset of World War II; however, by 1944 the
U.S. neutralized the Mariana Islands with the recapture of Saipan,
Tinian and Guam (Encyclopedia Britannica 2014, in litt.). Since World
War II, the U.S. military has developed a strong presence in the
Mariana Islands, particularly on the island of Guam, where both the
U.S. Navy and U.S. Air Force operate large military installations. The
island of Farallon de Medinilla is used for military ordnance training
(Berger et al. 2005, p. 130).
Currently, the U.S. Department of Defense is implementing a project
referred to as the ``Guam and Commonwealth of the Northern Mariana
Islands Military Relocation'' (Joint Guam Program Office (JGPO)-Naval
Facilities Engineering Command, Pacific (JGPO-NavFac, Pacific) 2010a,
p. ES-1; JGPO-NavFac, Pacific 2013, pp. 1-1--1-3). This military
relocation proposes: (1) the relocation of a portion of the U.S. Marine
Corps (Marine Corps) currently in Okinawa, Japan, which consists of up
to 5,000 Marines and their 1,300 dependents, as revised in the Draft
Supplemental Environmental Impact Statement (SEIS) (NavFac Engineering
Command Pacific 2014, p. ES-3), in addition to the development and
construction of facilities and infrastructure to support training and
operations on Guam and Tinian for the relocated Marines; (2) the
construction of a deep-draft wharf with shoreside infrastructure at
Apra Harbor, Guam, to support the U.S. Navy (Navy) transiting nuclear-
powered aircraft carrier; and (3) the development of facilities and
infrastructure on Guam to support the relocation of military personnel
and their dependents to establish and operate a U.S. Army (Army) and
Missiles Defense Task Force (JGPO-NavFac, Pacific 2010a, p. ES-7).
Both Guam and Tinian are located within the Mariana Islands Range
Complex, an area used by the Department of Defense (DOD) for readiness
training (JGPO-NavFac, Pacific 2010a, pp. ES-2--ES-3). The northern
two-thirds of Tinian are leased to the DOD, and the development of
these lands will negatively impact the habitat of 1 of the 23 species
in the forest ecosystem (Heritiera longipetiolata). The draft 2014 SEIS
focuses on the change to the preferred alternatives identified in the
2010 Final EIS (NavFac Engineering Command Pacific 2014, p. ES-1). The
preferred alternative sites on Guam for the implementation of the
Marine relocation efforts and development of a live-fire training range
complex now include Alternative A Finegayan and Alternative 5 Northwest
Field on Andersen Air Force Base (AFB), where, in total, 18 of the 23
species or their habitat are known to occur (13 of the 14 plants:
Bulbophyllum guamense, Cycas micronesica, Dendrobium guamense, Eugenia
bryanii, Hedyotis megalantha, Heritiera longipetiolata, Maesa walkeri,
Nervilia jacksoniae, Phyllanthus saffordii, Psychotria malaspinae,
Solanum guamense, Tabernaemontana rotensis, and Tuberolabium guamense;
and 5 of the 9 animals: the Mariana eight-spot butterfly, the Mariana
wandering butterfly, the Guam tree snail, the humped tree snail, and
the fragile tree snail) (NavFac Engineering Command Pacific 2014, pp.
ES-18--ES-22). The draft SEIS describes: (1) a more moderate
construction activity over 13 years instead of a 7-year intense
construction boom; (2) a significant reduction in peak and steady state
population increases, from more than 79,000 new Guam residents down to
7,400 new residents; (3) a reduction in the project area at Finegayan
from 2,580 ac (1,044 ha) to 1,452 ac (588 ha); (4) no new land
acquisition; (5) a reduction in project area at Northwest Field
(instead of Route 15); and (6) an overall decrease in power and water
demands (NavFac Engineering Command Pacific 2014, p. ES-3).
In conjunction with the relocation efforts discussed above, the
U.S. military is planning to improve existing and develop new live-fire
military training areas on the islands of Tinian and Pagan (JPGO-
NavFac, Pacific 2010a, pp. ES-5, ES-16-17, ES 19-20, ES-40; CJMT EIS-
OEIS (see below)). The Marine Corps (the Executive Agent designated by
the U.S. Pacific Command) recently published their ``Commonwealth of
the Northern Mariana Islands Joint Military Training Environmental
Impact Statement--Overseas Environmental Impact Statement (CJMT EIS-
OEIS at http://www.cnmijointmilitarytrainingeis.com/about). The CJMT
EIS-OEIS Final Scoping Summary Report informs the public that the
military plans to maximize use of DOD-leased lands within CNMI,
specifically Tinian and Pagan. The live-fire training range project
area on Tinian overlaps with the relocation effort areas discussed
above (the northern two-thirds of the island). Likewise, the live-fire
training range
[[Page 59371]]
project will negatively impact the plant species Heritiera
longipetiolata, as discussed above. On Pagan, both Alternative 1 and
Alternative 2 claim the entire island as a live-fire training area
(NavFac Engineering Command Pacific 2014, p. 13). In addition, the
live-fire training range project proposes the designation of special
use air and sea spaces around the entire islands of Pagan, Tinian, and
Aguiguan (just south of Tinian), and most of Saipan (north of Tinian).
If the entire island of Pagan is used as a live-fire training range
area, it would negatively impact 4 of the 23 species (Cycas
micronesica, Slevin's skink, humped tree snail, and habitat for
Bulbophyllum guamense) and their habitat in the forest ecosystem.
In addition to military spending, Guam's economy depends on
tourism. More than 1 million tourists visit Guam annually, mostly
arriving from Japan, Korea, and other Asian countries. In the early
1960s, military contributions to Guam's economy approached 60 percent,
with tourism adding almost another 30 percent. There was a downturn in
military presence and tourism in the 70s and 80s; however, recently,
with the projected increase in military employees and their dependents,
and with Guam seeking a ``no visa required'' status for visitors from
Russia and China, monitoring of sea ports and airports against
inadvertent introduction of harmful and invasive species is especially
important (http://www.guamvisitorsbureau.com/, accessed April 25, 2014;
http://guampedia.com/evolution-of-the-tourism-industry-on-guam-2/#toc-consequences-and-conclusions, accessed April 25, 2014) (see Factor D.
The Inadequacy of Existing Regulatory Mechanisms).
Political Division
Micronesia consists of several island groups: (1) Mariana Islands
(collectively the U.S. Commonwealth of the Northern Mariana Islands
(CNMI) and the U.S. Territory of Guam); (2) the Federated States of
Micronesia, including the Caroline Islands, Yap, Chuuk, Pohnpei, and
Kosrae and the Republic of Palau, the Republic of Kiribati, the
Republic of the Marshall Islands, Nauru, and Wake Island.
Islands in the Mariana Archipelago
A brief summary of each island in the Mariana archipelago, from
south to north, follows below (for detailed information see Stone 1970,
75 pp.; Falanruw et al. 1989, 11 pp.; Ohba 1994, 56 pp.; Mueller-
Dombois and Fosberg 1998, 32 pp.). Here we describe each of the islands
in the Mariana archipelago, even if the species addressed in this
proposed rule do not currently occur there, or were not found there
historically, to provide the reader context for understanding various
issues discussed in this document or in subsequent rulemakings that may
make reference to the various islands.
Guam
Guam is the largest and southernmost island of the Mariana Islands.
It is nearly 31 miles (mi) (50 kilometers (km)) long and from 4 to 9 mi
(7 to 15 km) wide, with a peak elevation of 1,332 feet (ft) (406 meters
(m)) at Mt. Lamlam (Muller-Dombois and Fosberg 1998, p. 269). Guam is
located in the northwestern Pacific Ocean, 1,200 mi (1,930 km) east of
the Philippines, 3,500 mi (5,632 km) west of the Hawaiian Islands, and
54 mi (87 km) south of Rota. The northern and southern regions of the
island show marked contrast due to their geologic history. The northern
region is an extensive, upraised, terraced, limestone plateau or
``mesa'' between 300 and 600 ft (90 and 183 m) above sea level
interrupted by a few low hills, of which two (Mataguac and Mt. Santa
Rosa) are volcanic in nature; others are exclusively coralline
limestone (e.g., Barrigada Hill and Ritidian Point (Stone 1970, p.
12)). The southern region is primarily volcanic material (e.g.,
basalts) with several areas capped by a layer of limestone (Stone 1970,
p. 12).
Of all the Mariana Islands, Guam contains the most extensive stream
and drainage systems, particularly in the Talofofo Region (Stone 1970,
p. 13; Muller-Dombois and Fosberg 1998, p. 269). Fairly extensive
wetland areas are located on both coasts of the southern region as well
as the higher elevation Agana Swamp located in the middle of the
island. Guam is also the most populated of all the Mariana Islands,
with more than 180,000 residents. Guam has experienced impacts from at
least 4,000 years of human contact, starting with the Chamorro,
followed by the Spanish, Germans, Japanese, and Americans (see ``Pre-
Historical Human Impact'' and ``Historical and Ongoing Human Impacts,''
above). World War II and subsequent U.S. military activity have also
negatively impacted natural habitats on Guam; however, the buffer zones
around the U.S. Navy and Air Force bases on Guam and conservation areas
designated on these bases support some of the rarest species. There are
three conservation areas designated by the Guam Department of Aquatic
and Wildlife Resources (GDAWR): (1) Anao Conservation Area; (2) Bolanos
Conservation Area; and, (3) Cotal Conservation Area (GDAWR 2006, p. 39;
Sablan Environmental, Inc. 2008, p. 3). Guam supports the forest,
savanna, stream, and cave ecosystems (see ``Mariana Islands
Ecosystems,'' below). Twenty of the 23 species addressed in this
proposed rule occur on Guam (all 14 plants: Bulbophyllum guamense,
Cycas micronesica, Dendrobium guamense, Eugenia bryanii, Hedyotis
megalantha, Heritiera longipetiolata, Maesa walkeri, Nervilia
jacksoniae, Phyllanthus saffordii, Psychotria malaspinae, Solanum
guamense, Tabernaemontana rotensis, Tinospora homosepala, and
Tuberolabium guamense; and 6 of the 9 animals: Slevin's skink (Cocos
Island, off Guam), the Mariana eight-spot butterfly, the Mariana
wandering butterfly, the Guam tree snail, the humped tree snail, and
the fragile tree snail. The Pacific sheath-tailed bat occurred on Guam
historically.
Rota
Just northeast of Guam (36 mi; 58 km) and southwest of Aguiguan (47
mi; 76 km), Rota is the fourth largest island in the Mariana Islands,
measuring 33 square miles (mi\2\) (96 square kilometers (km\2\)) in
land area (Mueller-Dombois and Fosberg 1998, p. 265; CNMI-SWARS 2010,
p. 6). The highest point on the island is Mount Sabana or the ``Sabana
plateau,'' at just over 1,600 ft (488 m) (Mueller-Dombois and Fosberg
1998, p. 265). The Sabana plateau is characterized by a savanna ringed
by forest that extends onto the surrounding karst limestone cliffs and
down the rugged slopes that encircle all sides of the Sabana (Mueller-
Dombois and Fosberg 1998, pp. 265-266). Rota consists primarily of
terraced limestone surrounding a volcanic core that protrudes from the
topmost plateau, or Sabana. The Sabana is noticeably wetter than the
rest of the island and is the only location known to support all four
orchids proposed for listing as endangered or threatened species in
this rule (Bulbophyllum guamense, Dendrobium guamense, Nervilia
jacksoniae, and Tuberolabium guamense) (Harrington et al. 2012, in
litt.).
Rota has experienced land alterations since the arrival of the
first Chamorro more than 4,000 years ago. When the Mariana Islands were
occupied by the Japanese (1914-1944) they cleared forest areas to plant
large sugarcane plantations and conducted phosphate mining on the
Sabana plateau (Amidon 2000, pp. 4-5; Engbring 1986, pp. 10, 27).
Although Rota was never invaded during World War II, it was heavily
bombed by U.S. military forces
[[Page 59372]]
(Engbring et al. 1986, pp. 8, 11). Rota has a population of
approximately 3,000 people. In recent years, three terrestrial
conservation areas have been designated on Rota by the CNMI Department
of Land and Natural Resources: (1) The Sabana Heights Wildlife
Conservation Area; (2) I-Chenchon Park Wildlife Conservation Area and
Bird Sanctuary; and, (3) Wedding Cake Mountain Wildlife Conservation
Area (Berger et al. 2005, p. 14).
Rota supports the forest, savanna, stream, and cave ecosystems.
Eleven of the 23 species addressed in this proposed rule currently
occur on Rota (7 of the 14 plants: Bulbophyllum guamense, Cycas
micronesica, Dendrobium guamense, Maesa walkeri, Nervilia jacksoniae,
Tabernaemontana rotensis, and Tuberolabium guamense; and 4 of the 9
animals: the Mariana wandering butterfly, the Rota blue damselfly, the
fragile tree snail, and the humped tree snail). The plants Heritiera
longipetiolata and Solanum guamense and the Pacific sheath-tailed bat
were known from Rota historically.
Aguiguan
Aguiguan is known as ``Goat Island'' due to the presence of a large
feral goat population (Engbring et al. 1986, p. 8). Located
approximately 8 km (5 mi) southwest of Tinian, Aguiguan is a small
uninhabited island measuring 7 mi\2\ (18 km\2\) in land area with a
peak elevation of 515 ft (157 m) at Mt. Alutom (CNMI-SWARS 2010, p. 6).
This island was historically inhabited by the Chamorro people (Russell
1998, pp. 90-91). Aguiguan is entirely limestone, with very steep
cliffs fringing nearly the entire island, making access difficult
(Berger et al. 2005, p. 36). There are no streams on the island
(Engbring et al. 1986, p. 8). During the Japanese occupation, large
areas of native forest were cleared for sugarcane plantations, a large
runway and other war-related structures (Engbring et al. 1986, p. 8;
Mueller-Dombois and Fosberg 1998, p. 264). Ecosystem types on Aguiguan
include forest and cave. Three of the 23 species addressed in this
proposed rule occur on Aguiguan: the Pacific sheath-tailed bat, the
humped tree snail, and Langford's tree snail. The plant Tuberolabium
guamense was known from Aguiguan historically.
Tinian
Located approximately 3 mi (5 km) southeast of Saipan and 7 mi (9
km) north of Aguiguan, Tinian is the third largest island in the
Mariana Islands, measuring 40 mi\2\ (101 km\2\) in area, with a peak
elevation of 584 ft (178 m) at Lasso Hill (Engbring et al. 1986, p. 5).
The island of Tinian has a population of more than 3,000 residents.
Tinian's climate is the same as that of Guam (see ``The Mariana
Islands,'' above). The island is predominantly limestone with low-lying
plateaus and ridges, and lacks surface streams (Stafford et al. 2005,
p. 15; Engbring et al. 1986, p. 5). Two small wetland areas, heavily
overgrown with no open water, Hagoi Marsh and Marpo Swamp, serve as a
domestic water source (Engbring et al. 1986, p. 5). Tinian has lost
most of its primary (native) forest, due initially to clearing for
agriculture by the Chamorro, followed by agricultural endeavors of
German colonialists in the early 1900s (e.g., coconut plantations) and
then by Japanese settlers after 1914 (e.g., sugarcane plantations)
(Berger et al. 2005, pp. 36-37). Impacts to Tinian's native vegetation
were then compounded by impacts from military activities during World
War II (Mueller-Dombois and Fosberg 1998, p. 262; Russell 1998, p. 98;
CNMI-SWARS 2010, pp. 6-7, 28-29). Currently, approximately 5 percent of
primary (native) forest remains on Tinian (Engbring et al. 1986, p.
25). Tinian supports the forest and cave ecosystems. Tinian currently
has no designated conservation areas. One of the 23 species addressed
in this proposed rule occurs on Tinian, Heritiera longipetiolata. The
plants Dendrobium guamense, Solanum guamense, and Tuberolabium
guamense, the Pacific sheath-tailed bat, and the humped tree snail were
known from Tinian historically.
Saipan
Located approximately 3 mi (4.5 km) northeast of Tinian, Saipan is
the second largest and second most populous of the Mariana Islands,
measuring 44 mi\2\ (115 km\2\) with a peak elevation of 1,555 ft (474
m) at Mt. Tapochau (Mueller-Dombois and Fosberg 1998, p. 256). The
island is composed primarily of terraced limestone peaks, with exposed
volcanic ridges and slopes (Mueller-Dombois and Fosberg 1998, p. 256).
Saipan supported a large population of Chamorro people for thousands of
years, followed by the Spanish, Germans, Japanese, and the U.S.
military forces, and was also heavily impacted by World War II. Saipan
is the site of one of the largest battles in the Pacific between U.S.
and Japanese forces. Much of Saipan's forests were destroyed during
World War II, with only pockets of native forest surviving (Engbring et
al. 1986, pp. 3-5, 10-12; Berger et al. 2005, pp. 38-39). Due to this
widespread destruction of native forests and subsequent erosion, the
nonnative tree Leucaena leucocephala (tangantangan) was seeded for
erosion control (Berger et al. 2005, p. 32). Tangantangan is now a
dominant tree species on the island, and forms a unique mixed-forest
habitat not reported from the other islands (CNMI-SWARS 2010, p. 7).
There are four conservation areas on Saipan: (1) Bird Island Wildlife
Preserve; (2) Kagman Wildlife Conservation Area and Forbidden Island
Sanctuary; (3) Marpi Forest; and (4) the Saipan Upland Mitigation Bank
(Berger et al. 2005, p. 14). Ecosystem types on Saipan include forest,
savanna, and cave. One of the 23 species addressed in this proposed
rule occurs on Saipan, the humped tree snail. The plants Bulbophyllum
guamense, Dendrobium guamense, and Solanum guamense, the Pacific
sheath-tailed bat, and the Mariana eight-spot butterfly were known from
Saipan historically.
Farallon de Medinilla
Located approximately 52 mi (83 km) northeast of Saipan, and 33 mi
(53 km) south of Anatahan, Farallon de Medinilla (FDM) is a small,
uninhabited island measuring less than 1 mi\2\ (3 km\2\) in area with a
peak elevation of 1,047 ft (319 m) (CNMI-SWARS 2010, p. 6). None of the
23 species are currently or historically documented from this island.
Anatahan
Located approximately 23 mi (37 km) south of Sarigan, and 33 mi (53
km) northwest of FDM, Anatahan is an uninhabited volcanic island with
recent activity, measuring 12 mi\2\ (31 km\2\) in land area, and a peak
elevation of 2,582 ft (788 m) (Mueller-Dombois and Fosberg 1998, p.
252; CNMI-SWARS 2010, p. 6). This island is believed to have been
inhabited by the Chamorro people, if not as a permanent residence, then
as a collection site for natural resources (Russell 1998, p. 87).
Climate on Anatahan is similar to Guam and the other southern Mariana
Islands (see ``The Mariana Islands,'' above); however, being at a more
northerly latitude, can be slightly cooler than the islands to the
south (Ohba 1994, p. 14). Notable physical features of Anatahan include
two volcanoes with an east to west trending summit depression formed by
overlapping summit craters (Berger et al. 2005, p. 11). The largest
caldera measures 1.5 by 2 mi (2 by 3 km) wide. Between 2003 and 2005,
Anatahan erupted several times, with the largest eruption occurring in
2005, covering the island with at least 6 ft (2 m) of volcanic ash and
destroying an estimated 98 percent of the forest and
[[Page 59373]]
savanna habitat (Berger et al. 2005, p. 11; Kessler 2011, pp. 321,
323). Coconut crabs (Birgus latro) and five species of resident land
birds were eliminated along with most plants and other animals;
however, cats (Felis catus), rats (Rattus spp.), and monitor lizards
(Varanus indicus) survived (Kessler 2011, p. 323). Vegetation is slowly
recovering, and if cats and rats were eliminated, Anatahan could be a
good site for the reintroduction of native species--a ``clean slate''
(Kessler 2011, pp. 323-324). At this time, none of the 23 species are
known to occur on Anatahan; however, the humped tree snail occurred
there historically.
Sarigan
Located approximately 40 mi (64 km) south of Guguan and 23 mi (37
km) northeast of Anatahan, Sarigan is an uninhabited, roughly
triangular, island measuring 2 mi\2\ (5 km\2\) in width with a peak
elevation of 1,801 ft (549 m) (CNMI-SWARS 2010, p. 6). The island is
believed to have been inhabited by the Chamorro people (Russell 1998,
p. 86). Sarigan consists of a low truncated volcanic cone with a 2,460-
ft (750-m)-wide summit crater containing a small ash cone. Other
notable physical features of Sarigan include irregular shorelines with
steep cliffs created by old lava flows (Berger et al. 2005, p. 12).
Sarigan has undergone complete eradication of feral ungulates,
following the recommendation of the 1998 Fish and Wildlife Biological
Opinion for U.S. Navy mitigation for their bombing activities on FDM.
The ungulate removal project was a cooperative effort by FWS, U.S.
Navy, CNMI Division of Fish and Wildlife (DFW), and the Northern
Islands Mayor's Office. The islands' native vegetation and fauna is now
increasing in species richness and population numbers (Kessler 2011,
pp. 320-322). Ecosystem types on Sarigan include forest and savanna.
Two of the 23 species are known to occur on Sarigan (Slevin's skink and
the humped tree snail). We are unaware of historical occurrences of the
other 21 species on Sarigan.
Guguan
Located approximately 19 mi (30 km) south of Alamagan and 40 mi (64
km) northeast of Sarigan, Guguan is an uninhabited island with volcanic
activity, measuring 2 mi\2\ (4 km\2\) and a peak elevation of 988 ft
(301 m) (Ohba 1994, p. 16). The island is not believed to have been
inhabited by the Chamorro people (Russell 1998, pp. 83-89). Its north
side is devoid of vegetation resulting from volcanic activity, and its
south side is a vegetated, eroded, volcanic cone. Other notable
physical features of Guguan include steep cliffs along the shoreline
and moist to wet ravines (SIO 2014, in litt.). Also notable is the
presence of dense seabird colonies (Ohba 1994, p. 16; Berger et al.
2005, p. 12). Guguan supports the forest ecosystem. The entire island
of Guguan is a designated conservation area (Berger et al. 2005, p.
15). One of the 23 species occurs on Guguan (Slevin's skink). The plant
Solanum guamense occurred on Guguan historically.
Alamagan
Located approximately 18 mi (29 km) north of Guguan and 30 mi (48
km) south of Pagan, Alamagan is an uninhabited island with volcanic
activity, measuring 4 mi\2\ (11 km\2\), and a peak elevation of 2,441
ft (744 m) at Mt. Alamagan (Ohba 1994, p. 16). Alamagan is an emergent
summit of a large stratovolcano (steep, many-layered volcano
characterized by periodic explosive eruptions) with a 1,148-ft (350-m)
deep summit crater at the center of the island (Berger et al. 2005, p.
12). Most of the historically recent eruptions have been violently
explosive (Berger et al. 2005, p. 12). The island was inhabited by the
Chamorro people (Russell 1998, p. 86). Alamagan supports the forest and
savanna ecosystems. Two of the 23 species are known to occur on
Alamagan (Slevin's skink and the humped tree snail). We are unaware of
historical occurrences of the other 21 species on Alamagan.
Pagan
Located 42 mi (68 km) from Agrihan and 30 mi (48 km) from Alamagan,
Pagan is the fifth largest island in the Marianas archipelago, and the
largest of the northern Mariana Islands, with an area of 19 mi\2\ (48
km\2\) (Ohba 1994, p. 17). Four volcanoes comprise Pagan: Mt. Pagan in
the north, and an unnamed complex of three older volcanoes to the south
(Ohba 1994, p. 17; Smithsonian Institution 2014a, in litt.). These
volcanoes are connected by a narrow isthmus. The highest point on this
island is Mt. Pagan, which rises 1,870 ft (570 m) above sea level. Mt.
Pagan is one of the most active volcanoes in the Mariana Islands, with
its most recent eruption in 2012 (Smithsonian Institution 2014b, in
litt.). The largest eruption during historical times took place in
1981, when lava buried 10 percent of the island, and ash covered the
entire island, forcing the 53 residents to flee to Saipan (Smithsonian
Institution 2014b, in litt.). The island of Pagan supports the forest
and savanna ecosystems. Three of the 23 species are known to occur on
Pagan, the tree Cycas micronesica and the animals Slevin's skink and
the humped tree snail. The plant Bulbophyllum guamense occurred
historically on Pagan.
Agrihan
Located approximately 64 mi (102 km) south of Asuncion, and 39 mi
(63 km) north of Pagan, Agrihan is an almost perfectly round, active
volcanic cone (Ohba 1994, p. 17). None of the 23 species addressed in
this proposed rule are known to have historically occurred, or to
currently occur, on Agrihan, but other listed species, the Mariana
fruit bat and the Micronesian megapode, occur there.
Asuncion
Asuncion is located approximately 23 mi (37 km) southeast of Maug
and 62 mi (100 km) north of Agrihan. This island is an active,
uninhabited volcano measuring 3 mi\2\ (7 km\2\), with a peak elevation
of 2,923 ft (891 m) (Ohba 1994, p. 18; Mueller-Dombois and Fosberg
1998, p. 245). Historically, Asuncion was inhabited by Chamorro peoples
when Sanvitores arrived in the mid 1600s, and as evidenced by coconut
groves (Mueller-Dombois and Fosberg 1998, p. 235). The long interval
since Asuncion's last confirmed eruption in 1906 (Smithsonian
Institution 2014c, in litt.), in conjunction with its high summit often
enclosed by clouds (Ohba 1994, p. 18), affords this cone-shaped
volcanic island densely forested slopes with diverse vegetation.
Asuncion supports the forest and savanna ecosystems (Ohba 1994, p. 18).
The entire island of Asuncion is a designated conservation area (Berger
et al. 2005, p. 15). One of the 23 species addressed in this proposed
rule is known to occur on Asuncion (Slevin's skink). The plant Solanum
guamense occurred historically on Asuncion.
Maug
Located approximately 43 mi (70 km) south of Uracas and 24 mi (39
km) north of Asuncion, Maug consists of three small, uninhabited islets
(East Island, West Island, and North Island). The three islets are the
emergent portions of a largely submerged volcano, with a central lagoon
within a sunken crater (Ohba 1994, p. 18; Mueller-Dombois and Fosberg
1998, p. 244). The collective land mass of the three islets measures
0.8 mi\2\ (2 km\2\) with the highest elevation at 745 ft (227 m) at
North Island (Ohba 1994, p. 18; Mueller-Dombois and Fosberg 1998, p.
244). Historically, Chamorro people inhabited Maug (Russell 1998, p.
88), and the islets were briefly inhabited by the Japanese during World
War II (Russell
[[Page 59374]]
1998, pp. 96-97). Each of the three islets consists of narrow rocky
ridges covered primarily by grasslands, sedges, and scrub; however,
larger trees such as Hernandia sp., Pisonia grandis, and Terminalia
catappa have been reported to occur in ravines on the leeward sides
(Ohba 1994, p. 18; Mueller-Dombois and Fosberg 1998, pp. 244-245).
Ecosystems on Maug include forest and savanna, which currently provide
habitat for large breeding colonies of a variety of seabirds (Ohba
1994, p. 18). All three islets that comprise Maug are designated as a
conservation area (Berger et al. 2005, p. 15). None of the 23 species
addressed in this proposed rule are known to currently occur on the
islands of Maug. The plant Solanum guamense occurred historically on
Maug.
Uracas
Uracas (Farallon de pajaros), is the northernmost island of the
Mariana archipelago, roughly 43 mi (70 km) northwest of Maug. The
island is an active, uninhabited volcano measuring 0.9 mi\2\ (2 km\2\)
and with a peak elevation of 1,180 ft (334 m) (Ohba 1994, p. 18). None
of the 23 species addressed in this proposed rule, or any previously
listed species, are known to have historically occurred, or to
currently occur, on Uracas.
An Ecosystem-Based Approach to Assessing the Conservation Status of 23
Species in the Mariana Islands
In this document, we have analyzed the threats to each of the 23
Mariana Islands species individually to determine the appropriate
status of each species on its own merits under the Act. However,
because many of these species, and particularly those that share the
same habitat types (henceforth referred to as ecosystems), share a very
similar suite of threats, we have organized the 23 species addressed in
this proposed rule by common ecosystem for efficiency, to reduce
repetition for the reader, and to reduce publication costs. Therefore,
we begin our analysis of the potential threats to each of the 23
species by first describing the relevant ecosystems in which these
species occur, to avoid repeating the habitat characteristics
associated with each individual species found in the same ecosystem.
Organizing the rule in this way also allows us to describe threats that
affect multiple species occurring in shared ecosystems in a more
efficient manner, again reducing repetition for the reader and saving
publication costs.
In addition, as an incidental benefit of assessing the threats to
the 23 species using shared ecosystems as an organizational tool, we
have laid the groundwork for better addressing threats to these
species, should they be listed. On the Mariana Islands native species
occurring in the same habitat types depend on many of the same physical
and biological features and the successful functioning of their
specific ecosystem to survive. Because these species that share
ecosystems face a suite of shared threats, managing or eliminating
these threats holistically at an ecosystem level is more cost effective
and should lead to better resource protection for all native species.
Cost-effective management of these threats requires implementation of
conservation actions at the ecosystem level to enhance or restore
critical ecological processes and provide for long-term viability of
species and their habitat. Organizing the 23 Mariana Islands species by
shared ecosystems sets the stage for a conservation management approach
of protecting, restoring, and enhancing critical ecological processes
at an ecosystem scale for the long-term viability of all associated
native species in a given ecosystem type and locality, thus potentially
preventing the future imperilment of any additional species that may
require protection. This approach is in accord with the primary stated
purpose of the Act (see section 2(b)): ``to provide a means whereby the
ecosystems upon which endangered species and threatened species depend
may be conserved.''
Each of the 23 Mariana Islands species is found in one of the four
ecosystem types described in this rule: forest, savanna, stream, and
cave (Table 2). Of the 23 species, only the Pacific sheath-tailed bat
is found in more than one ecosystem type (forest and cave).
Table 2--The 23 Mariana Islands Species and the Ecosystems Upon Which
They Depend
------------------------------------------------------------------------
Species
Ecosystem ---------------------------------------
Plants Animals
------------------------------------------------------------------------
Forest.......................... Bulbophyllum Pacific sheath-
guamense. tailed bat.
Cycas micronesica. Slevin's skink.
Dendrobium Mariana eight-spot
guamense. butterfly.
Eugenia bryanii... Mariana wandering
Heritiera butterfly.
longipetiolata. Humped tree snail.
Maesa walkeri..... Langford's tree
Nervilia snail.
jacksoniae. Guam tree snail.
Psychotria Fragile tree
malaspinae. snail.
Solanum guamense..
Tabernaemontana
rotensis.
Tinospora
homosepala.
Tuberolabium
guamense.
Savanna......................... Hedyotis
megalantha.
Phyllanthus
saffordii.
Stream.......................... .................. Rota blue
damselfly.
Cave............................ .................. Pacific sheath-
tailed bat.
------------------------------------------------------------------------
For all of the proposed species, we identified and evaluated those
factors that are threats to each individual species specifically
(species-specific threats), as well as those factors which are common
threats to all of the species of a given ecosystem type (ecosystem-
level threats). For example, the degradation of habitat by nonnative
ungulates is considered a direct or indirect threat to 17 of the 23
species proposed for listing as endangered or threatened species. We
have labeled such threats that are shared by all species within the
same ecosystem as an ``ecosystem-level threat,'' because they impact
all proposed species occurring in that ecosystem type in terms of the
nature of the impact, its severity, timing, and scope. Beyond
ecosystem-level threats, we further identified and evaluated species-
specific threats that may be unique to certain species. For example,
the threat of predation by nonnative flatworms is unique and specific
to the four tree snails addressed in this rule.
Mariana Islands Ecosystems
For the purposes of organizing our threats discussion for the 23
species by shared habitats, we describe four broad Mariana Islands
ecosystems: Forest,
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savanna, stream, and cave, based on physical features, elevation,
substratum, vegetation type, and hydrology (see ``The Mariana
Islands,'' above). We acknowledge the presence of other ecosystems
(e.g., coastal, wetland) in the Mariana Islands, however we limit our
discussion to these four because they are the relevant ecosystems that
support the 23 species proposed for listing as endangered or threatened
species in this rule.
Forest Ecosystem
There are two substrate types in the forest ecosystem, limestone
and volcanic (Stone 1970, pp. 9, 14, 18-24; Falanruw et al. 1989, pp.
6-9; Ohba 1994, pp. 19-29; Mueller-Dombois and Fosberg 1998, p. 243).
The annual rainfall in the forest ecosystem lies within the archipelago
average, ranging from 78 to 100 inches (in) (2,000 to 2,500 millimeters
(mm)), with a rainy season from June or July through October or
November. The temperature of the forest ecosystem mirrors the
archipelago monthly averages, between 75 degrees Fahrenheit ([deg]F)
and 82 [deg]F (24 degrees Celsius ([deg]C) and 28 [deg]C), with
extremes of 64 [deg]F and 95 [deg]F (18 [deg]C and 35 [deg]C). Multiple
plant species are present throughout the forest ecosystem, and on most
of the islands; however, variations in species structure are observed
(Fosberg 1960, pp. 37, 56-59, plates 1-40; Falanruw et al. 1989, pp. 6-
9; Ohba 1994, pp. 19-29; Mueller-Dombois and Fosberg 1998, pp. 257,
268, 270-271).
Native canopy species in the forest ecosystem (as defined here)
include but are not limited to: Artocarpus mariannensis, Barringtonia
asiatica, Claoxylon spp., Cordia subcordata, Cyathea spp., Cyanometra
ramiflora, Elaeocarpus joga, Ficus prolixa, Guamia mariannensis,
Hernandia labyrinthica, H. sonora, Maytenus thompsonii,
Merrilliodendron megacarpum, Ochrosia mariannensis, Pandanus dubius, P.
tectorius, Pisonia grandis, Pouteria obovata, and Premna obtusifolia
(Falanruw et al. 1989, pp. 6-9; Raulerson and Rinehart 1991, pp. 6-7,
11, 14, 20, 24, 28, 33, 50, 52-53, 62-63, 72, 91, 96, 104; Ohba 1994,
pp. 19-29; Mueller-Dombois and Fosberg 1998, pp. 257, 268, 270-271;
Wiewel et al. 2009, pp. 206-207). Native subcanopy species include but
are not limited to: Aglaia mariannensis, Aidia cochinchinensis,
Allophyllus timoriensis, Cyathea aramaganensis, Eugenia palumbis, E.
reinwardtiana, Hibiscus tiliaceus, Neisosperma oppositifolia,
Psychotria mariana, and Xylosma nelsonii (Stone 1970, pp. 9, 14, 18-24;
Falanruw et al. 1989, pp. 6-9; Raulerson and Rinehart 1991, pp. 13, 47,
56, 59, 68-69, 77, 84, 88; Ohba 1994, pp. 19-29; Mueller-Dombois and
Fosberg 1998, pp. 252-253, 257, 268, 272); and native understory
species include but are not limited to: Discocalyx megacarpa, Hedyotis
spp., Nephrolepis bisserrata, N. hirsutula, Phyllanthus marianus, and
Piper guamense (Falanruw et al. 1989, pp. 6-9; Ohba 1994, pp. 19-29;
Mueller-Dombois and Fosberg 1998, pp. 247, 268). Further, in select
areas of the forest ecosystem, usually where the forest is situated to
receive and retain more moisture, the canopy trees are covered in
various mosses and epiphytic ferns and orchids (Mueller-Dombois and
Fosberg 1998, p. 268).
Dominant canopy, subcanopy, and understory species can vary from
one location to the next on the same island, and from island to island.
These species can be endemic to one island, occur on one or more of the
southern islands (e.g., the understory species Discocalyx megacarpa),
or occur on one or more of the northern islands (e.g., Cyathea
aramaganensis). In addition, biologists have observed overlap of forest
species on limestone and volcanic substrata, suggesting that physical
properties may be more important than chemical properties of these
substrates in determining vegetation characteristics (Mueller-Dombois
and Fosberg 1998, pp. 262-264). Elevation also contributes to
variations in vegetation, as observed on Mt. Alutom, Mt. Almagosa, Mt.
Lamlam, and Mt. Bolanus on Guam; the Rota Sabana; and on the slopes of
the northern islands (Stone 1970, pp. 9, 14, 18-24; Falanruw 1989, pp.
4-6; Mueller-Dombois and Fosberg 1998, pp. 262-264); although in some
cases there is no definite correlation with elevation (i.e., the
moisture-retaining, moss-and-epiphyte-covered sections of the forest
ecosystem are found near the coast in some areas and also at mid to
high elevations) (Fosberg 1960, p. 30).
Additionally, biologists have observed a change in distribution of
Hernandia species with elevation. For example, H. sonora, dominant on
the coastal side of the forest ecosystem, changes distinctly to H.
labyrinthica as the elevation increases (Amidon 2000, p. 49). The
significance of these interpretations of forest-associated species in
the Mariana archipelago to the 14 plants in this rule is not adequately
definitive to subclassify a forest type for each of the species in this
rule; therefore, we describe a general forest ecosystem here, with the
substrate, temperatures, rainfall, and associated native canopy,
subcanopy, and understory species, listed above. The forest ecosystem
supports 21 of the 23 species proposed for listing as endangered or
threatened species in this rule (all except the plants Hedyotis
megalantha and Phyllanthus saffordii, which occur only in the savanna
ecosystem).
Savanna Ecosystem
The savanna ecosystem of the Mariana Islands is characterized by
volcanic substrate, primarily of basalts, with laterite soil (red clay
rich in iron and aluminum) and a vegetation type in which grasses are
the dominant plants. The savanna ecosystem on Guam is segmented by
multiple narrow ravine forests, with some grassland (Mueller-Dombois
and Fosberg 1998, pp. 241, 272). Savanna is considered a primary
ecosystem type; however, human clearing and burning of forests and the
presence of feral ungulates have contributed toward the expansion of
secondary savanna into areas that previously supported the forest
ecosystem (Mueller-Dombois and Fosberg 1998, pp. 241-243; Stone 1970,
p. 31). Some authorities have suggested that savanna should not be
classified as a native ecosystem in the Mariana Islands (Athens and
Ward 2004, p. 27); however, we concur with Mueller-Dombois and Fosberg
(1998, pp. 241-243), Stone (1970, pp. 14, 19, 21, 23, 30), and Hunter-
Anderson (2009, 16 pp.), that savanna can be classified as a primary
ecosystem type. Hunter-Anderson published a detailed analysis of
charcoal samples, historical climate change trends, patterns of soil
deposition, known agricultural techniques used by the early settlers,
and Holocene-age pollen and spore studies, all indicating that the
first settlers did not use fire to create or enlarge new open areas
(savanna) for agriculture (Hunter-Anderson 2009, 16 pp.). These
findings support the theory that the savanna ecosystem type existed
prior to human presence in the Mariana Islands.
Annual rainfall in the savanna ecosystem ranges from 78 to 100 in
(2,000 to 2,500 mm), with a rainy season from June or July through
October or November. Likewise, the temperature of the savanna ecosystem
averages between 75 [deg]F and 82 [deg]F (24 [deg]C and 28 [deg]C),
with extremes of 64 [deg]F and 95 [deg]F (18 [deg]C and 35 [deg]C).
Several endemic plant species are associated with the savanna
ecosystem: the grass Dimeria chloridiformis; the small herbaceous
perennial Dianella saffordiana, and the small tree Phyllanthus
mariannensis (Stone 1970, pp. 19, 388, 549; Mueller-Dombois and Fosberg
1998, pp. 241-243; Hunter-Anderson 2009, 16 pp). Other native savanna
species include
[[Page 59376]]
the shrubs Decaspermum fruticosum, Dodonaea viscosa, Melastoma
marianum, Myrtella bennigseniana, and Wikstroemia elliptica, the grass
Digitaria mariannensis; and subspecies of the fern Dicranopteris.
Another dominant but controversial component of the savanna ecosystem
is the grass Miscanthus floridulus (giant miscanthus). Although M.
floridulus occurred historically on Pagan as analyzed in fossil records
studied in 1958 (Fosberg and Corwin 1958, pp. 8-9), and currently
occurs on almost all of the 15 Mariana Islands, this species is
considered invasive by most Mariana Islands ecologists. Recent field
observations revealed that M. floridulus often grows in widespread,
monotypic stands, whereas endemic plants such as Hedyotis megalantha
and Phyllanthus saffordii grow compatibly within patches of the native
fern Dicranopteris linearis (Gawel 2012, in litt.). The savanna
ecosystem supports 2 of the 14 plant species proposed for listing as
endangered or threatened species in this rule (Hedyotis megalantha and
Phyllanthus saffordii).
Cave Ecosystem
The cave ecosystem is largely located in limestone (karst) areas on
the southern islands of Saipan, Aguiguan, Rota, and Guam (Taborosi
2004, pp. 14-15). Limited areas of cave ecosystem also occur on the
volcanic northern Mariana Islands where lava tubes and other crevices
occur. The cave ecosystem includes stream caves, lava tubes, sea caves,
and solution caves (Taborosi 2004, pp. 2, 11; Water and Environmental
Research Institute and the Western Pacific-Island Research and
Education Initiative (WERI-IREI) 2014, in litt.). Solution caves are
the most common, except for on Tinian, which has mostly flank margin
caves (Stafford et al. 2005, p. 20; WERI-IREI 2014, in litt.). Solution
caves are cavities that have developed in the limestone substrate
through the action of running water, erosion, and collapse (WERI-IREI
2014, in litt). Flank margin caves form at the distal margin of the
fresh water lens, where mixing of fresh and saline waters occurs
(Stafford et al. 2005, p. 20).
Ambient temperatures and rainfall in the cave ecosystem are the
same as for surrounding areas in the Marianna Islands (average of 75
[deg]F to 90 [deg]F (24 [deg]C to 32 [deg]C); rainfall 78 in (2,000 mm)
per year) (Wiles et al. 2009, p. 10 in O'Shea and Valdez 2009). Thermal
characteristics of the interiors of caves show little variability, and
relative humidity is high. Humidity measured in four caves on Aguiguan
ranged from 92 to 96 percent (O'Shea and Valdez 2009, p. 78 in O'Shea
and Valedez 2009). Internal cave temperatures (between caves) vary less
than a few degrees, between 79 [deg]F to 82 [deg]F (26 [deg]C to 28
[deg]C), and temperatures within each cave are essentially constant
(O'Shea and Valdez 2009, p. 77 in O'Shea and Valedez 2009). No major
air movement was detected within caves to indicate any complex thermal
patterns (O'Shea and Valdez 2009, p. 77 in O'Shea and Valedez 2009).
Cave sizes range from small (less than 49 ft (15 m) long and 538
ft\2\ (50 m\2\)) in floor area, with low rock overhangs, narrow
vertical crevices, various cavities at the base of cliffs or under
large boulders; to medium (538 ft\2\ to 1,076 ft\2\ (50 to 100 m\2\) in
floor area, with wider rooms; to large (over 1,076 ft\2\ (100 m\2\)) in
floor area, with ceiling heights reaching 16 to 98 ft (5 to 30 m))
(Wiles et al. 2009, p. 11 in O'Shea and Valdez 2009).
Cave ecosystems suitable for the Pacific sheath-tailed bat should
be within or near mature native forest, to provide an attainable food
source (Wiles et al. 2009, p. 10 in O'Shea and Valdez 2009; Gorresen et
al. 2009, p. 44 in O'Shea and Valdez 2009). Pacific sheath-tailed bats
prefer the larger caves, if available (Wiles et al. 2009, p. 15 in
O'Shea and Valdez 2009), but may also be found in smaller caves,
especially where there may be less disturbance (e.g., use by goats or
humans).
One of the 23 species proposed for listing as endangered in this
rule, the Pacific sheath-tailed bat, depends on the cave ecosystem for
its life-history needs.
Stream Ecosystem
Streams can be a part of a wetland ecosystem; however, for this
proposed rule, we discuss only the more narrowly defined stream
ecosystem. Only one species addressed in this rule is found in the
stream ecosystem, the Rota blue damselfly, which occurs only on Rota.
Only two of the Mariana Islands have permanent streams, Guam and
Rota. Guam has 14 named watersheds with more than 100 streams and
rivers (WERI-IREI 2014, in litt.). Saipan has a brackish-water lake,
Lake Susupe. Intermittent headwaters originating from Mount Tagpochau
and the Fina Sisu ridge during heavy rains provide water to the lake,
but there are no permanent streams on Saipan (Wong and Hill 2000, p.
1). Currently on Tinian, there are no permanent streams, and only one
functional wetland, Lake Hagoi (Stinson 1995, in litt.). The limestone
substrate of these southern islands is very porous, and rain that falls
is evaporated, consumed by plants, runs directly off the land surface
into the ocean, or recharges ground water (Carruth 2003, p. 13). The
northern islands are not known to have permanent streams; however,
Pagan has a freshwater lake with hot sulfur springs, and a small
brackish-water lake (Guam.net, http://www.guam.net/pub/sshs/depart/science/mancuso/marianas/pagan/pagan.htm, accessed April 30, 2014).
The western end of Rota is dominated by the ``Sabana'' region,
which is an irregular plateau 1,300 ft (400 m) high, 2.5 mi by 1.6 mi
(4 km by 2.5 km), with two prominent peaks nearly 1,600 ft (500 m)
high. The Sabana area is very porous, with internal caves, and any
ponding water after a rainfall event filters quickly into the
substrate, leaving ephemeral streams (Keel et al. 2007, pp. 12-16). The
east, north and west of the plateau gradually drops off in a series of
terraces. The south side of the plateau has steep cliffs in the
Talakhaya area, with springs and the only surface streams on the island
(Keel et al. 2007, p. 3). The stream ecosystem on Rota encompasses
these streams and springs in the Talakhaya area, and is the only known
location of the Rota blue damselfly (as described in ``Animals--Rota
Blue Damselfly,'' below).
On Rota, there is a distinct rainy season from July through
December, with an average annual rainfall of 102 in (2600 mm). Ambient
temperature averages 81 [deg]F (27 [deg]C) (see ``Islands in the
Mariana Archipelago,'' above). The rainy season and rainfall amounts
can dramatically change (become drier) due to the El Ni[ntilde]o-
Southern Oscillation (ENSO) which also affects stream levels (Keel et
al. 2007, p. 6).
The vegetation along the streams consists primarily of mature,
tall-canopied, native limestone forest (Keel et al. 2007, p.10; U.S.
Forest Service 2014, in litt.). The vegetation type and components are
further described in Forest Ecosystem, above.
The Talakhaya Springs within the Sabana Watershed are used as a
primary domestic water source. The springs consist of Water Cave (also
known as Matan Hanum Spring) and As Onon Spring. The municipal water is
obtained by gravity flow from these two springs (up to 1.8 million
gallons a day (2.8 cubic feet per second)) (Keel et al. 2007, pp. 1, 5;
Stafford et al. 2002, p. 17). Under ordinary climatic conditions, this
area supplies water in excess of demand but ENSO-induced drought
conditions can lead to significantly reduced discharge, or may
completely dewater the streams (Keel et al. 2007, pp. 3, 6, 19). In
1998, water captured from the
[[Page 59377]]
springs was inadequate for municipal use, and water rationing was
instituted (Keel et al. 2007, p. 6). As the annual temperature rises
resulting from global climate change, other weather regime changes such
as increases in droughts, floods, and typhoons will occur (Giambelluca
et al. 1991, p. iii). Increasing night temperatures cause a change in
mean precipitation, with increased occurrences of drought cycles (Loope
and Giambelluca 1998, pp. 514-515; Emanuel et al. 2008, p. 365; U.S.
Global Change Research Program (US-GCRP) 2009, pp. 145-149, 153; Keener
et al. 2010, pp. 25-28; Finucane et al. 2012, pp. 23-26; Keener et al.
2012, pp. 47-51).
The limestone substrate of Rota is porous, with filtration through
central Sabana being the sole water source for the few streams on the
island and for human use. There are no other ground water supplies on
the island, and limited storage capacity. The Rota blue damselfly is
dependent upon any water that escapes the Talakhaya Springs naturally,
what is not already removed for human use. The likelihood of dewatering
of the Talakhaya Springs is high due to climate change causing
increased ENSO conditions, and increased human demand. The ``Public and
Agency Participation'' section of the Comprehensive Wildlife
Conservation Strategy for the Commonwealth of the Northern Mariana
Islands (2005, p. 347) cites ``individuals state the the Department of
Public Works has been increasing their water extraction from Rota's
spring/stream systems. Historically, this water source flowed year-
around, yet now they are essentially dry most of each year.'' See the
species description in ``Rota blue damselfly,'' below, and the ``Water
Extraction'' section under Factor E. Other Natural or Manmade Factors
Affecting Their Continued Existence, below, for further discussion.
Description of the 23 Mariana Islands Species
Plants
In order to avoid confusion regarding the number of populations of
each species (i.e., because we do not consider an individual plant to
represent a viable population), we use the word ``occurrence'' instead
of ``population.'' Additionally, we use the word occurrence to refer
only to wild (i.e., not propagated and outplanted) individuals because
of the uncertainty of the persistence to at least the second generation
(F2) of the outplanted individuals. A population consists of mature,
reproducing individuals forming populations that are self-sustaining.
Also, there is a high potential that one or more of the outplanted
populations may be eliminated by normal or random adverse events such
as fire, nonnative plant invasion, or disease, before a seed bank can
be established.
Bulbophyllum guamense (cebello halumtano), an epiphyte in the
orchid family (Orchidaceae), is known from widely distributed
occurrences on the southern Mariana Islands of Guam and Rota, in the
forest ecosystem (Ames 1914, p. 13; Raulerson and Rinehart 1992, p. 90;
Costion and Lorence 2012, pp. 54, 66; Global Biodiversity Information
Facility (GBIF) 2012a-Online Herbarium Database). Bulbophyllum guamense
was recorded historically on Guam from clifflines encircling the
island, and on the slopes of Mt. Lamlam and Mt. Almagosa. As recently
as 1992, this species was reported to occur in large mat-like
formations on trees ``all over the island,'' (Guam) (Raulerson and
Rinehart 1992, p. 90). Currently, numbers have declined dramatically,
and there are only 4 known occurrences (3 on Guam and 1 on Rota)
totaling fewer than 250 individuals on Guam and fewer than 30
individuals on Rota. Historically, this species also occurred on Pagan
(last observed in 1984) and Saipan (last observed in 1970).
Bulbophyllym guamense has thus been lost from two of the four islands
where it formerly occurred, and only a few small populations of the
species remain on Guam and Rota. The remaining individuals of B.
guamense are vulnerable to the effects of continued habitat loss and
destruction from agriculture, urban development, nonnative animals and
plants, fires, and typhoons, combined with predation by nonnative
invertebrates such as slugs.
Cycas micronesica (fadang), a cycad in the cycad family
(Cycadaceae), is known from Guam, Rota, and Pagan, as well as Palau
(politically the independent Republic of Palau) and Yap (geographically
part of the Caroline Islands; politically part of the Federated States
of Micronesia), in the forest ecosystem (Hill et al. 2004, p. 280;
Keppel et al. 2008, p. 1,006; Cibrian-Jaramillo et al. 2010, pp. 2,372-
2,375; Marler 2013, in litt.).
Just 10 years ago, Cycas micronesica was ubiquitous on the island
of Guam, and similarly common on Rota. Cycas micronesica is currently
under attack by a nonnative insect, the cycad aulacaspis scale
(Aulacaspis yasumatsui) that is causing rapid mortality of plants at
all locations (Marler 2014, in litt.). As of January 2013, C.
micronesica mortality reached 92 percent on Guam, and cycads on Rota
are experiencing a similar fate (Marler 2013, in litt.). All seedlings
of C. micronesica in a study area were observed to die within 9 months
of infestation by C. yasumatsui (see Factor C. Disease and Predation,
below for further discussion) (Marler and Muniappan 2006, p. 3; Marler
and Lawrence 2012, p. 233; Marler 2013, pers. comm.; Western Pacific
Tropical Research Center 2012, p. 4).
Currently, there are 15 to 20 occurrences of Cycas micronesica
totaling 900,000 to 950,000 individuals on the Micronesian Islands of
Guam, Rota, Pagan, Yap, and Palau. On Guam and Rota there are fewer
than 630,000 (Marler 2013, pers. comm.). These totals do not
distinguish between successfully reproducing adults and juveniles
(Marler 2013, pers. comm.), which, because of the effects of the cycad
aulacaspis scale, implies that the number of extant individuals that
can successfully reproduce is much lower. On Guam, there are four
fragmented occurrences, totaling fewer than 516,000 individuals: one
occurrence along the shoreline to the base of the limestone cliffs on
the north side; a second occurrence beginning at the forest edge along
the cliffs and continuing into the forest on the north side; a third
occurrence on the northern plateau; and a fourth occurrence along the
ravines and rock outcrops on the southern side, with a few individuals
occurring across the savanna.
On Rota, there are four known occurrences within the forest
ecosystem, totaling fewer than 111,500 individuals (Marler 2013, in
litt.). On the northeast shore the first occurrence totals fewer than
25,500 individuals; the second occurrence, on the northwest shore,
totals fewer than 21,600 individuals; the third occurrence on the south
shore totals fewer than 63,600 individuals; and the fourth occurrence
on Wedding Cake peninsula totals fewer than 300 individuals.
There are likely a relatively limited number of individuals of
Cycas micronesica on Pagan. In recent surveys, Pratt (2011, pp. 33-42)
reported finding representatives of the species in a ravine on the
southwestern part of the island.
Yap consists of a group of four islands, three of which are
separated by water but share a common reef, with a total land area of
39 mi\2\ (102 km\2\). On Yap, there are three occurrences of Cycas
micronesica totaling 288,450 individuals (Marler 2013, in litt). Palau
consists of three larger islands, Babeldaob, Koror, and Ngeruktabel,
and between 250 and 300 smaller islands referred to as the ``Rock
Islands.'' The
[[Page 59378]]
total land area is 177 mi\2\ (458 km\2\). On Palau, four occurrences of
C. micronesica total fewer than 2,500 individuals: (1) two occurrences
on Ngeruktabel Island total fewer than 900 individuals, (2) one
occurrence on Ngesomel Island totals fewer than 600 individuals, and
(3) possibly as many as 1,000 individuals scattered on the Rock Islands
(Marler 2013, in litt.). The aulacaspis scale was observed on the main
islands of Palau in 2008 (Marler 2014, in litt.), and is expected to
reach Yap as well (Marler 2013, in litt.).
Protecting and preserving Cycas micronesica on the islands of Guam
and Rota is important, as it is an integral component of the forest
ecosystem, and over 50 percent of the known individuals occur on these
islands. The nonnative cycad aulacaspis scale quickly causes mortality
of all life stages of C. micronesica, preventing reproduction of C.
micronesica, and leading to its extirpation (see Factor C. Disease and
Predation, below). The magnitude of the ongoing threats of predation by
the scale and nonnative animals, secondary infestations by other
insects, and loss of habitat due to development, typhoons, climate
change, and direct damage and destruction by military live-fire
training is large, and these threats are imminent. Although C.
micronesica presently is found in relatively high numbers, the factors
affecting this species can result in very rapid mortality of large
numbers of individuals. A study by Marler and Lawrence (2012) shows
that if the ongoing negative population density trajectory for C.
micronesica established over 4 years is sustained, extirpation of C.
micronesica from Guam and Rota will occur by 2019.
Dendrobium guamense (no common name (NCN)), an ephiphyte in the
orchid family (Orchidaceae), is known from Guam, Rota, and Tinian, in
the forest ecosystem (Ames 1914, p. 14; Raulerson and Rinehart 1992, p.
98; Costion and Lorence 2012, p. 66). As recently as the 1980s, this
species was common in trees on Guam and Rota, with more than 12
occurrences on Guam and 17 occurrences on Rota (Bishop Museum 2013--
Online Herbarium Database; Consortium Pacific Herbarium (CPH) 2012a--
Online Herbarium Database, 5 pp.). Currently, there are 9 occurrences
totaling approximately 550 individuals distributed among these islands.
On Guam, there are 4 occurrences totaling fewer than 250 individuals
(Harrington et al. 2012, in litt). On Rota, there are 4 occurrences of
D. guamense, totaling fewer than 300 individuals (Harrington et al.
2012, in litt). There is one reported occurrence on the island of
Tinian, with an unknown number of individuals (Quinata et al. 1994, p.
8; CPH 2012a--Online Herbarium Database, 5 pp.). Historically, D.
guamense was also known from Saipan, in the forest ecosystem (CPH
2012a--Online Herbarium Database, 5 pp.). Formerly relatively common,
the remaining populations of D. guamense and habitat for its
reintroduction to Saipan are at risk; D. guamense populations are
decreasing on Guam, Rota, and Tinian, and both the species and its
habitat continues to be negatively affected by continued habitat loss
and destruction from agriculture, urban development, nonnative animals
and plants, fires, and typhoons, combined with predation by nonnative
invertebrates such as slugs.
Eugenia bryanii (NCN), a perennial shrub in the Myrtle family
(Myrtaceae), is known only from Guam. Historically, E. bryanii occurred
on windy, exposed clifflines along the west and east coasts of the
island, and from along the Pigua River, in the forest ecosystem
(Costion and Lorence 2012, p. 82; Gutierrez 2012, in litt.). Currently,
E. bryanii is known from 5 occurrences totaling fewer than 420
individuals (Gutierrez 2014, in litt.). Populations of E. bryanii, a
single island endemic, are decreasing from initial numbers observed on
Guam, and these remaining small populations are at risk, due to
continued habitat loss and destruction from agriculture, urban
development, nonnative animals and plants, and typhoons, combined with
herbivory by deer.
Hedyotis megalantha (paudedo), a perennial herb in the coffee
family (Rubiaceae), is known only from the savanna ecosystem on Guam.
Historically, H. megalantha was reported solely from Guam; however,
because several herbarium records reported this species on Rota and
Saipan, we investigated other reports and taxonomic and genetic
analyses concerning the range of this species. We believe the Rota and
Saipan reports are misidentifications of one or more of the other
Hedyotis species also found in the Mariana Islands (Fosberg et al.
1993, pp. 63-79; CPH 2012b--Online Herbarium Database; World Checklist
of Select Plant Families (WCSP) 2012a--Online Herbarium Database).
Between 1911 and 1966, this species ranged from the mid-central
mountains and west coast of Guam, south to Mt. Lamlam (Bishop Museum
2013-Online Herbarium Database). Currently, H. megalantha is known from
one large scattered occurrence totaling fewer than 1,000 individuals on
southern Guam (Costion and Lorence 2012, pp. 54, 86; Gutierrez 2012, in
litt.; Bishop Museum 2013--herbarium database; Gutierrez 2013, in
litt.). Hedyotis megalantha typically occurs as lone individuals rather
than in patches or groups (Gutierrez 2013, in litt.). In sum, the
single known occurrence of H. megalantha, a single island endemic, is
decreasing from initial numbers observed on Guam, and the remaining
individuals are at continued risk due to ongoing habitat loss and
destruction from agriculture, urban development, nonnative animals and
plants, fires, and typhoons, combined with habitat destruction and
direct damage by recreational vehicles.
Heritiera longipetiolata (ufa-halomtano; looking glass tree), a
tree in the hibiscus family (Malvaceae), is known only from the Mariana
Islands. A few herbarium records have cited H. longipetiolata on Palau,
Chuuk, Pohnpei, and the Eastern Caroline Islands; however, upon a
thorough review of the literature and herbarium records, and conferring
with local botanical experts, we conclude that these few outlying
occurrences are actually H. littoralis, not H. longipetiolata (Stone
1970, pp. 23, 420-421; Raulerson and Rinehart 1991, p. 94; Wiles 2012,
in litt.; Center for Plant Conservation 2010, in litt.; CPH 2012c--
Online Herbarium Database; GBIF 2014--Online Herbarium Database;
Harrington et al. 2012, in litt.; Lorence 2013, in litt.).
Historically, Heritiera longipetiolata is reported from Guam, Rota,
Saipan, and Tinian, in the forest ecosystem (Stone 1970, p. 420;
Raulerson and Rinehart 1991, p. 94; CPH 2012c--Online Herbarium
Database; GBIF 2014--Online Herbarium Database). By 1997, there were
about 1,000 individuals on Guam, several hundred on Tinian, and fewer
than 100 on Saipan, with none observed on Rota (Wiles in Internation
Union for Conservation of Nature (IUCN) Red List 2014, in litt.).
Currently, H. longipetiolata is known from 9 occurrences totaling fewer
than 160 individuals, on Guam, Saipan, and Tinian, all within the
forest ecosystem (M and E Pacific, Inc., pp. 6, 8, 31, 78; Harrington
et al. 2012, in litt; Grimm 2013, in litt). On Tinian, H.
longipetiolata is known from fewer than 10 individuals (Williams 2013,
in litt.). On Saipan, H. longipetiolata is known from 3 occurrences,
totaling fewer than 30 individuals. Wiles stated that there is strong
evidence that H. longipetiolata is not regenerating, and that seedlings
and seeds are eaten by ungulates and crabs (Wiles in IUCN Red List
2014, in litt.). Heritiera longipetiolata is on Guam's endangered
species list, listed as Vulnerable on IUCN's Red List of
[[Page 59379]]
Threatened Species, and is also a species of concern for Guam's Plant
Extinction Prevention Program. The remaining populations of H.
longipetiolata persist only in small numbers, and are decreasing from
initial numbers observed on Guam, Saipan, and Tinian. With fewer than
200 individuals remaining across three islands, the species Heritiera
longipetiolata and habitat for the recovery of the species on Rota are
at risk due to ongoing habitat loss and destruction from agriculture,
urban development, nonnative animals and plants, and typhoons.
Herbivory by pigs and deer, and habitat and direct destruction by
military live-fire training also contribute to the decline of H.
longipetiolata.
Maesa walkeri (NCN), a shrub or small tree in the primrose family
(Primulaceae), is found only in the Mariana Islands. Historically, M.
walkeri is known from the islands of Guam and Rota, within the forest
ecosystem (Fosberg and Sachet 1979, pp. 368-369; Raulerson and Rinehart
1991, p. 67; M and E Pacific, Inc. 1998, pp. 31, 79; Costion and
Lorence 2012, p. 84; CPH 2012d--Online Herbarium Database; GBIF 2012b--
Online Herbarium Database; Wagner et al. 2012--Flora of Micronesia).
Several voucher specimens (preserved and labeled representative whole
plants or plant parts, used to compare and correctly identify plant
species, usually kept as part of an herbarium collection) report M.
walkeri from the Carolinian Island of Pohnpei, but after careful review
of the best available data (cited above) we conclude that M. walkeri is
endemic to the Mariana Islands. Historically, M. walkeri was known from
at least 13 occurrences on Guam and 9 occurrences on Rota (Bishop
Museum 2014--Online Herbarium Database). Currently, M. walkeri is known
from 4 occurrences in the forest ecosystem on Guam and Rota, totaling
fewer than 60 individuals. On Guam, there are two individuals (M and E
Pacific, Inc. 1998, pp. 31, 79; Grimm 2013, in litt.). On Rota, M.
walkeri is known from 2 occurrences totaling approximately 50
individuals (Harrington et al. 2012, in litt.; Gawel 2013, in litt.).
Maesa walkeri is also a species of concern for Guam's Plant Extinction
Prevention Program.
In summary, the species Maesa walkeri is vulnerable to extinction
due to its very limited numbers, totaling fewer than 60 individuals
(with only 2 on Guam). The remaining populations of M. walkeri are
decreasing from initial numbers observed on Guam and Rota, and continue
to be affected by ongoing habitat loss and destruction from
agriculture, urban development, nonnative animals and plants, fires,
and typhoons. The impacts on the species are exacerbated by the effects
of low numbers of individuals resulting in loss of vigor and genetic
representation, which limits its ability to compete with other species
and adapt to changes in environmental conditions.
Nervilia jacksoniae (NCN), a small herb in the orchid family
(Orchidaceae), is found only in the Mariana Islands. Historically, N.
jacksoniae occurred on the islands of Guam and Rota, in the forest
ecosystem, and ranged from northern to central Guam and only the
southwestern point of Rota (Rinehart and Fosberg 1991, pp. 81-85;
Raulerson and Rinehart 1992, p. 118; Costion and Lorence 2012, p. 67).
Currently, there are approximately 15 occurrences totaling at least 520
individuals on the islands of Guam and Rota, in the forest ecosystem
(Harrington et al. 2012, in litt.). On Guam, N. jacksoniae is known
from 2 occurrences totaling fewer than 200 individuals (M and E
Pacific, Inc. 1998, p. 58; Grimm 2012, in litt.; McConnell 2012, pers.
comm.). On Rota, N. jacksoniae is known from 13 scattered occurrences
totaling at least 320 individuals in the forest ecosystem (Rinehart and
Fosberg 1991, pp. 81-85; Raulerson and Rinehart 1992, p. 118; Costion
and Lorence 2012, p. 67; CPH 2012e--Online Herbarium Database; GBIF
2012c--Online Herbarium Database; McConnell 2012, pers. comm.).
Populations of N. jacksoniae are decreasing from initial numbers
observed on Guam and Rota and are at risk of further losses due to
continued habitat loss and destruction from agriculture, urban
development, nonnative animals and plants, fires, and typhoons,
combined with predation by nonnative invertebrates such as slugs.
Phyllanthus saffordii (NCN), a woody shrub in the Phyllanthaceae
family, is historically known only from the southern part of Guam
within the savanna ecosystem. Several literature and database sources
report this species from the northern Mariana Islands (Costion and
Lorence 2012, pp. 82-83; Wagner 2012--Flora of Micronesia; U.S.
Department of Agriculture-Agricultural Research Service-Germplasm
Resources Information Network (USDA-ARS-GRIN) 2013--Online Database;
WCSP 2012b--Online Database); however, a thorough review of the
literature, databases, and herbaria records revealed recorded
occurrences only on Guam (Merrill 1914, pp. 104-105; Glassman 1948, p.
181; Stone 1970, pp. 387-388; Pratt 2011, p. 59; Gutierrez 2012, in
litt.; GBIF 2012d--Online Herbarium Database; Bishop Museum 2013--
Online Herbarium Database; Smithsonian Institution 2014-Flora of
Micronesia Database). Until the early 1980s, P. saffordii ranged from
central to southern Guam (Bishop Museum 2014--Herbarium Database).
Currently, P. saffordii is known from 4 scattered occurrences on
southern Guam, totaling fewer than 1,400 individuals (Gutierrez 2013,
in litt.; Gawel et al. 2013, in litt.). In summary, populations of P.
saffordii, a single island endemic, are decreasing from initial numbers
observed on Guam and are at risk, due to continued habitat loss and
destruction from agriculture, urban development, nonnative animals and
plants, fires, and typhoons, combined with habitat destruction and
direct damage by recreational vehicles.
Psychotria malaspinae (aplokhating-palaoan), a shrub or small tree
in the coffee family (Rubiaceae), is known only from Guam.
Historically, P. malaspinae was known from scattered occurrences on the
northeastern and southwestern sides of Guam, in the forest ecosystem
(Merrill 1914, pp. 148-149; Stone 1970, pp. 554-555; Raulerson and
Rinehart 1991, p. 83; Fosberg et al. 1993, pp. 111-112; Costion and
Lorence 2012, pp. 54, 85-86; Bishop Museum 2014--Online Database;
Wagner 2012--Flora of Micronesia; WCSP 2012c--Online Database).
Currently, P. malaspinae is known from only three occurrences, each of
a single individual (M and E Pacific, Inc. 1998, pp. 67, 79). None of
these individuals has been observed within the last 5 years. Biologists
searched for this species during rare plant surveys conducted in July
2012; however, none were located (Harrington et al. 2012, in litt.). A
specimen collected from the Ritidian National Wildlife Refuge on Guam
in August 2013 is currently pending identification (Gawel et al. 2013,
in litt.). Psychotria malaspinae is also a species of concern for
Guam's Plant Extinction Prevention Program.
The species Psychotria malaspinae, a single island endemic, has
been reduced to three known individuals in the wild, rendering this
species vulnerable to extinction. These remaining individuals are at
risk, due to continued habitat loss and destruction from agriculture,
urban development, nonnative animals and plants, and typhoons.
Herbivory by pigs and deer, combined with the effects of low numbers of
individuals, which results in loss of vigor and genetic representation,
and limits its ability to compete with other species and adapt to
changes in environmental conditions, contribute to the decline of P.
malaspinae.
Solanum guamense (berenghenas halomtano), a small shrub in the
[[Page 59380]]
nightshade family (Solanaceae), is known only from the Mariana Islands
(Merrill 1914, pp. 139-140; Stone 1970, p. 521; Costion and Lorence
2012, p. 89). Historically, S. guamense was reported from Guam, Rota,
Saipan, Tinian, Asuncion, Guguan, and Maug (Stone 1970, p. 521; GBIF
2012e--Online Database; Bishop Museum 2014--Online Database).
Currently, S. guamense is known from a single occurrence of one
individual on Guam, in the forest ecosystem (Perlman and Wood 1994, pp.
135-136).
Once ranging across multiple islands, Solanum guamense is now
vulnerable to extinction, the species having been reduced to a single
remaining individual on Guam. This species, and habitat for its
reintroduction to Rota, Saipan, Tinian, Asuncion, Guguan, and Maug, are
at risk, due to continued habitat loss and destruction from
agriculture, urban development, nonnative animals and plants, and
typhoons. Herbivory by pigs and deer, combined with the effects of low
numbers of individuals, which results in loss of vigor and genetic
representation and limits its ability to compete with other species and
adapt to changes in environmental conditions, contribute to the decline
of S. guamense.
Tabernaemontana rotensis (NCN), a small to medium-sized tree in the
dogbane family (Apocynaceae), is historically known from Guam and Rota,
in the forest ecosystem (University of Guam (UOG) 2007, p. 6). The
genus is widespread throughout tropical and subtropical regions. In
2004 (69 FR 1560, January 9, 2004), we proposed to list T. rotensis;
however, in April 2004 (69 FR 18499) we did not list T. rotensis
because an authoritative monographic work on the genus submerged this
species in an expansive interpretation of the widespread species T.
pandacaqui. In 2011, a genetic study was conducted on specimens from
Rota, Guam, Asia, and the Pacific, to determine if those individuals on
the Mariana Islands are a monophyletic lineage. The study determined
that T. rotensis is a valid species, distinct from the widespread T.
pandacaqui (Reynaud 2012, 27 pp. + appendices). In 2004, T. rotensis
was known from 8 individuals on Rota, and at least 250 individuals on
Guam. In 2007, more than 21,000 individuals were found throughout
Andersen AFB, with a population structure representing seedlings,
juveniles, and reproductive, mature individuals (UOG 2007 p. 4).
Currently, on Rota, T. rotensis is known from two occurrences, each
composed of fewer than five individuals (Harrington et al. 2012, in
litt.). On Guam, T. rotensis is known from 6 occurrences totaling
approximately 21,000 individuals (M and E Pacific, Inc. 1998, p. 61;
UOG 2007, pp. 32-42).
In summary, populations of Tabernaemontana rotensis on Guam and
Rota are at risk, due to continued habitat loss and destruction from
agriculture, urban development, nonnative animals and plants, fires,
and typhoons, combined with vandalism. The greatest concern regarding
this species is not of population structure, but the small proximity of
occurrences in an area that may be developed according to the proposed
AFB and Navy base expansions (UOG 2007, p. 5; JGPO-NavFac Pacific
2010a, 2010b; JGPO-NavFac Pacific 2014).
Tinospora homosepala (NCN), a vine in the moonseed family
(Menispermaceae), is historically known only from Guam (Merrill 1914,
p. 83; Stone 1970, pp. 27, 277; Costion and Lorence 2012, pp. 92-93).
Currently, T. homosepala is known from 3 occurrences totaling
approximately 30 individuals, in the forest ecosystem (Yoshioka 2008,
p. 15; Gawel et al. 2013, in litt.). There is discussion among
botanists as to whether or not T. homosepala is either the same as a
commonly occurring species found throughout Malaysia and the
Philippines or a variety of that species (T. glabra) (Costion and
Lorence 2012, pp. 92-93; Gawel et al. 2013, in litt.). Tinospora
homosepala differs from T. glabra in having equal-sized sepals (petal-
like structures of the calyx) as opposed to the outer sepals being much
smaller than inner sepals as in T. glabra (Costion and Lorence 2012, p.
93; Forman 1981, pp. 381, 417, and 419).
While these discussions note that additional research on the
taxonomy of Tinospora homosepala is appropriate to address questions,
no changes to the currently accepted taxonomy have been proposed,
although Forman (1981, p. 419) notes that, if fruits of T. homosepala
are discovered and are indistinguishable from T. glabra, it may be
preferable to reduce T. homosepala to subspecific rank under T. glabra.
Regardless, any future reduction in rank from full species status to
that of a subspecies or variety would not, in itself, disqualify this
taxon from protection under the Act. All known individuals of T.
homosepala on Guam are said to be males that reproduce clonally
(Yoshioka 2008, p. 15; Gawel et al. 2013, in litt.). Clonal
reproduction limits genetic diversity, reducing the ability of the
species to form new genetic combinations to fit changing environmental
conditions (Stebbins 1957, p. 352). In summary, the species T.
homosepala, a single island endemic, has been reduced to roughly 30
individuals on Guam, and it is possible that no female representatives
of this species remain. These few remaining individuals of the species
are at risk of extinction, due to continued habitat loss and
destruction from nonnative animals and plants, and typhoons, and by
genetic limitations as a result of the possible loss of potential
sexual reproduction.
Tuberolabium guamense (NCN) (Trachoma guamense is a synonym), an
epiphyte in the orchid family (Orchidaceae), is known only from the
Mariana Islands. Historically, T. guamense was reported from the
islands of Guam, Rota, Tinian, and Aguiguan (Raulerson and Rinehart
1992, p. 127; CPH 2012f--Online Herbarium Database; GBIF 2012f--Online
Database). The Royal Botanical Gardens at Kew's online database (WCSP
2012d--Online Database) describes the range for T. guamense as the
Mariana Islands and the Cook Islands; however, we were unable to
confirm this with herbarium specimens citing the Cook Islands as a site
for collection (CPH 2012f--Online Herbarium Database; GBIF 2012f--
Online Herbarium Database; Smithsonian Institution 2014-Online
Herbarium Database). In 1992, T. guamense was found in ``trees and
shrubs all over the island'' (Raulerson and Rinehart 1992, p. 127), and
the Consortium of Pacific Herbaria has records of 22 collections from
Guam, 5 collections from Rota, 15 collections from Tinian, and 3
collections from Aguiguan (CPH 2012f-Online Herbarium Database).
Currently, T. guamense is known from three occurrences: one occurrence
of one individual on Guam and two occurrences on Rota, in the forest
ecosystem (Gawel et al. 2013, in litt.; Harrington et al. 2012, in
litt.).
In summary, populations of Tuberolabium guamense are decreasing
from initial numbers observed on Guam and Rota, and habitat for its
reintroduction to Tinian and Aguiguan is at risk. The remaining few
representatives of this species and its habitat are vulnerable to
ongoing threats posed by the continued habitat loss and destruction
from agriculture, urban development, nonnative animals and plants,
fires, and typhoons. Herbivory by slugs, combined with the effects of
low numbers of individuals which results in loss of vigor and genetic
representation, and limits its ability to compete with other species
and adapt to changes in environmental conditions, contribute to the
decline of T. guamense.
[[Page 59381]]
Animals
Pacific Sheath-Tailed Bat
The Pacific sheath-tailed bat (Emballonura semicaudata rotensis) is
a small insectivorous bat (forearm length about 1.8 in (45 mm), weight
0.2 ounces (oz) (5.5 grams (g)), in the family Emballonuridae, an Old
World bat family that has an extensive distribution primarily in the
tropics (Lemke 1986, pp. 743-745; Nowak 1994, pp. 90-91; Lemke 1986,
pp. 743-744; Koopman 1997, pp. 358-359; Wiles and Worthington 2002, pp.
1-3; O'Shea and Valdez 2009, pp. 9-10). The Pacific sheath-tailed bat
is a rich brown to dark brown above and paler below (Walker and
Paradiso 1983, p. 211). The common name ``sheath-tailed bat'' refers to
the nature of the tail attachment: the tail pierces the tail membrane
and its tip appears completely free on the upper surface of the
membrane (Walker and Paradiso 1983, p. 209).
The Pacific sheath-tailed bat was once common and widespread in
Polynesia and Micronesia, and is the only insectivorous bat recorded
from a large part of this area (Hutson et al. 2001, p. 138). The
classification of the subspecies has received varied treatment, but the
most thorough and recent taxonomic evaluation for this subspecies was
conducted by Koopman (1997, pp. 358-360). Koopman recognizes four
subspecies: E. s. rotensis, endemic to the Mariana Islands (Guam and
the CNMI); E. s. sulcata, occurring in Chuuk and Pohnpei; E. s.
palauensis, found in Palau; and E. s. semicaudata, occurring in
American and Independent Samoa, Tonga, Fiji, and Vanuatu. Historically,
in the Mariana Islands, the Pacific sheath-tailed bat was known from
Guam, Rota, Aguiguan, Tinian, Saipan, and possibly Anatahan and Maug
(Lemke 1986, pp. 743-745; Steadman 1999, p. 321; Wiles and Worthington
2002, pp. 1-3). Currently, the Pacific sheath-tailed bat appears to be
extirpated from all but one island in the Mariana Islands, Aguiguan,
where a single remaining population of this subspecies is estimated to
number between 359 to 466 individuals (Wiles and Worthington 2002, p.
15; Wiles 2007, pers. comm.; O'Shea and Valdez 2009, pp. 2-3).
The biology of this subspecies, including reproduction, habitat
use, and diet, was, until recently, largely unknown (Wiles and
Worthington 2002, p. 19; Esselstyn et al. 2004, p. 304). A study by
O'Shea and Valdez (2009, pp. 95-97) reveals more life-history
information. Fecal pellets of the Pacific sheath-tailed bat collected
from two caves on Aguiguan show these bats consume a diverse array of
prey, mostly consisting of small-sized insects including hymenopterans
(ants, wasps, and bees), lepidopterans (moths), and coleopterans
(beetles) as the three major food items (O'Shea and Valdez 2009, pp.
63-65).
The Pacific sheath-tailed bat appears to be cave-dependent,
roosting during the day in a wide range of cave-types, including
overhanging cliffs, karst limestone caves, crevices, and lava tubes
(Grant et al. 1994, pp. 134-135; O'Shea and Valdez 2009, pp. 105-108).
Bats and cave swiftlets (birds, Aerodramus spp.) may be found sharing
caves (Lemke 1986, pp. 744-745; Tarburton 2002, pp. 106-107; Wiles and
Worthington 2002, pp. 7, 13; Lemke 1986, pp. 744-745). Analysis of data
collected from echolocation stations deployed across Aguiguan indicates
that the bats' peak activity and occurrences are related to canopy
cover, vegetation structure, and distance to known roosts; and that
native limestone forest is preferred foraging habitat (O'Shea and
Valdez 2009, pp. 105-108).
A previous survey of habitat use on Aguiguan in 2003 revealed that
bats foraged almost entirely in forests (native and nonnative) near
their roosting caves and clearly did not utilize the non-forested
habitats on the island (Esselstyn et al. 2004, p. 307). Bruner and
Pratt (1979, p. 3) also observed sheath-tailed bats foraging in native
forests on Pohnpei. Large roosting colonies appear to be common for the
Palau subspecies, but smaller aggregations may be more typical of at
least the Mariana Island subspecies and perhaps other Emballonura found
elsewhere (Wiles et al. 1997, pp. 221-222; Wiles and Worthington 2002,
pp. 15, 17). In 1995, roosting bats on Aguiguan were detected in only 5
of 77 caves surveyed (Wiles 2007, pers. comm.), with colony sizes
ranging from 2 to 64 individuals. Observations in 2007 indicated that
the bats preferred large caves (over 1,076 ft\2\ (100 m\2\)) in floor
area, with ceiling heights reaching 16 to 98 ft (5 to 30 m)) (see
``Cave Ecosystem,'' above, for further cave description), as nearly all
of the caves used for roosting were characterized as large by
researchers (GDAWR 1995, pp. 95-96; O'Shea and Valdez 2009, pp. 9-17;
Wiles and Worthington 2002, pp. 7, 13). The Pacific sheath-tailed bat
is nocturnal and typically emerges around dusk to forage on insects
(Craig et al. 1993, p. 51; Wiles and Worthington 2002, p. 13).
The Pacific sheath-tailed bat populations have declined drastically
in the Mariana Islands, and the subspecies is now known to occur on
only Aguiguan. While populations of other Pacific sheath-tailed bat
subspecies appear to be healthy in some locations, mainly in the
Caroline Islands, they have also declined drastically in other areas,
including Independent and American Samoa, and Fiji (Bruner and Pratt
1979, p. 3; Grant et al. 1994, pp. 133-134; Wiles et al. 1997, pp. 222-
223; Wiles and Worthington 2002, pp. 17-19). For example, populations
of sheath-tailed bats (E. s. semicaudata) were noted to precipitously
decline from American Samoa in the 1970s (Grant et al. 1994, pp. 133-
134). It is speculated that disturbance of caves where the sheath-
tailed bats roosted by successive storms contributed to the decline of
sheath-tailed bats; however, it was noted that some caves were still
inhabited by swiftlets (Grant et al. 1994, p. 134). Other factors
contributing to the decline of sheath-tailed bats in American Samoa may
include starvation during extended storms, human disturbance of caves,
bombing and shelling during World War II, pesticides, and guano mining;
however, the exact causes of sheath-tailed bat population declines in
the American Samoa and other South Pacific islands are still uncertain
(Grant et al. 1994, pp. 135-136). In contrast, large numbers of
individuals of the sheath-tailed bat subspecies E. s. palauensis were
readily observed by Wiles et al. in the 1990s (1997, p. 224).
In summary, the Pacific sheath-tailed bat (E. s. rotensis), once
found on multiple islands on Guam and the Marianas, has been reduced to
a single, small remaining population. The species has exhibited a
significant decline from its initial numbers observed on Guam, Rota,
Aguiguan, Tinian, Saipan, and its persistence in a single remaining
population renders it vulnerable to extinction. The remaining
population of the Pacific sheath-tailed bat continues to experience
threats due to continued habitat loss and destruction from agriculture,
urban development, nonnative animals, and typhoons. In addition,
predation by monitor lizards, and possible predation by the brown tree
snake, may contribute to the observed decline of the Pacific sheath-
tailed bat.
Slevin's Skink
Slevin's skink (Emoia slevini, guali'ek halom tano) is a small
lizard in the reptile family Scincidae, the largest lizard family in
number of worldwide species. Slevin's skink was first described in 1972
by Walter C. Brown and Marjorie V.C. Falanruw, which is the most recent
and accepted taxonomy (Brown and Falanruw 1972, p. 107). It
[[Page 59382]]
is the only lizard endemic to the Mariana Islands and is on the
Government of Guam's Endangered Species List (Fritts and Rodda 1993, p.
3; Rodda et al. 1997, p. 568; Rodda 2002, p. 2; CNMI DFW 2005, p. 174;
GDAWR 2006, p. 107; Guam Department of Agriculture 2014, in litt.).
Slevin's skink previously occurred on the southern Mariana Islands
(Guam, Cocos Island, Rota, Tinian, and Aguiguan), where it is now
extirpated, except from Cocos Island off of Guam, where it was recently
rediscovered (Fritts and Rodda 1993, p. 2; Steadman 1999; Lardner 2013,
in litt.).
Surveys conducted in the 1980s and 1990s show that Slevin's skink
was present on the northern islands of Sarigan, Guguan, Alamagan,
Pagan, and Asuncion (Berger et al. 2005, pp. 174-175; GDAWR 2006, p.
107; Vogt 1997, in litt.); however, none were captured on Anatahan or
Agrihan or ever reported historically from these islands (Berger et al.
2005, p. 175; Rodda et al. 1991, p. 202). The skink has not yet been
reported from the southern island of Saipan, or the northern islands of
Farallon de Medinilla, Maug, or Uracas. The densest population was on
Alamagan (island area of 2,800 ac; 1,130 ha) in the early 1990s, but
researchers believe that overgrazing by introduced ungulates may
preclude the long-term viability of that population (Rodda 2002, p. 3;
Fritts and Rodda 1993, p. 1). The catch rate (number of lizards
captured per hour) quadrupled on Sarigan in a survey conducted in 2007,
after eradication of feral ungulates from the island in 1998 (Vogt
2007, p. 5-5; Kessler 2011, p. 322). Its current status on Aguiguan,
Guguan, Pagan, and Asuncion is unknown.
Slevin's skink measures 3 in (77 mm) from snout to cloaca vent (the
opening for reproductive and excretory ducts), although length can vary
slightly (Vogt and Williams 2004, p. 65). Fossil remains indicate its
prehistoric size was much larger, up to 4.3 in (110 mm) in length
(Rodda 2010, p. 3). Slevin's skink is darkly colored, from olive to
brown, with darker flecks in a checkerboard pattern, and a light orange
to bright yellow underside (Vogt and Williams 2004, p. 65). Their skin
tends to be shiny, and is very durable and tough. Juveniles may appear
cream-colored (Vogt and Williams 2004, p. 65; Rodda 2010, p. 3).
Slevin's skink is a fast-moving, alert, insectivorous lizard,
typically found on the ground or at ground level, and active during the
day. Based on both older and more recent observations, the species
occurs in the forest ecosystem, with most individuals observed on the
forest floor using leaf litter as cover (Brown and Falanruw 1972, p.
110; GDAWR 2006, p. 107; Cruz et al. 2000, p. 21; Lardner 2013, in
litt.). Occasionally, individuals were observed in low hollows of tree
trunks (Brown and Falanruw 1972, p. 110). It is a social species, seen
often in the company of other individuals, including other nonnative
skink species (Vogt and Williams 2004, pp. 59, 65). The females carry
their eggs internally and give birth to live young (Brown 1991, pp. 14-
15). Other specific life-history or habitat requirements of Slevin's
skink are not well documented (Rodda 2002, p. 3).
Slevin's skink was most numerous in the Mariana Islands during
prehistoric times, before the introduction of other competing lizards
and predators, and loss of native forest (Vogt and Williams 2004, p.
65; Berger et al. 2005, p. 175). After World War II, Slevin's skink had
notably vanished from the larger southern Mariana Islands (Fritts and
Rodda 1993, p. 4), which suggests the species may be sensitive to
habitat destruction or changes in land use practices (Fritts and Rodda
1993, p. 4; Berger et al. 2005, p. 174). Slevin's skink had not been
recorded on Guam since 1945 or on Cocos Island since the early 1990s
(Rodda and Fritts 1992, p. 171; Campbell 2011, in litt.), until a
specimen was captured on Cocos Island in January of 2011 (Campbell
2011, pers. comm.). Over half the island is developed for a hotel, and
it is a tourist destination (Fritts and Rodda 1993, p. 2). Only about
25 ac (10 ha) of suitable habitat is available on Cocos Island, and it
is periodically overwashed during typhoons (Fritts and Rodda 1993, pp.
2, 5). The northern islands of its known occurrence provide less than
19,843 ac (8,030 ha) of land area, not all of which is suitable
habitat. Slevin's skink is no longer found on the larger southern
islands of Guam, Rota, and Tinian, which combined, provide the largest
land area, 179,892 ac (72,800 ha). This species no longer occurs in 90
percent of its historical range.
In summary, once widespread, the remaining known populations of
Slevin's skink are made up of a few individuals on Cocos Island, and
occurrences of undetermined numbers of individuals on Alamagan and
Sarigan. Populations of Slevin's skink are decreasing from initial
numbers observed on Cocos Island, Alamagan, Pagan, and Asuncion, and it
has not been reobserved on Guam, Rota, Tinian, and Aguiguan; the
species has been lost from 90 percent of its former range. The
remaining populations of Slevin's skink are at risk, due to continued
habitat loss and destruction from agriculture, urban development,
nonnative animals, and typhoons. Predation by rats, monitor lizards,
and possible predation by the brown tree snake (if the snake is
introduced to other islands), also contribute to the decline of
Slevin's skink.
Mariana Eight-Spot Butterfly
The Mariana eight-spot butterfly (Hypolimnas octocula marianensis),
a butterfly in the Nymphalidae family, is known solely from the islands
of Guam and Saipan, in the forest ecosystem (Schreiner and Nafus 1996,
p. 2; Schreiner and Nafus 1997, p. 26). It may be extirpated from
Saipan (Schreiner and Nafus 1997, p. 26). This subspecies was
originally described by Butler and is recognized as a distinct taxon in
Swezey (1942, p. 35), the most recent and accepted taxonomy for this
species. Like most nymphalid butterflies, orange and black are the two
primary colors exhibited by this subspecies. The males are smaller than
the females by at least a third or more in size. Males are
predominantly black with an orange stripe running vertically on each
wing. The stripe on the hindwings exhibits small black dots in a
vertical row. Overall, the females appear more orange in color than the
males, and black bands across the apical (top) margins of both pair of
wings are exhibited. Along the inner margin of these black bands, large
white spots are exhibited across the entire length of the wings
(Schreiner and Nafus 1997, pp. 15, 26-27). The caterpillar larva of
this species is black in color with red spikes and a black head,
differentiating it from similar-appearing caterpillars including
Hypolimnas bolina, H. anomala, and Pipturus spp. (Schreiner and Nafus
1996, p. 10; Schreiner and Nafus 1997, p. 26).
The larvae of this butterfly feed on two native plants, Procris
pedunculata (no common name), and Elatostema calcareum (tapun ayuyu)
(Schreiner and Nafus, 1996, p. 1). Both of these forest herbs (family
Urticaceae) are found only on karst substrate within the forest
ecosystem, draped over boulders and small cliffs, presumably out of
reach of browsing ungulates (Schreiner and Nafus 1996, p. 1; Rubinoff
2013, in litt.). When adult butterflies were observed, they were always
in proximity to the host plants (Rubinoff 2011, in litt.; Rubinoff
2013, p. 1). Both of the host plant species are rare in their range,
and both plants are believed to be susceptible to feral ungulate
grazing based upon anecdotal observations indicating they occur only in
the extremely rugged limestone karst terrain believed to be avoided by
most
[[Page 59383]]
ungulates (Rubinoff 2013, in litt.). The two host plants have been
recorded on the islands of Guam, Rota, Saipan, and Tinian (Schreiner
and Nafus 1996, p. 2; Schreiner and Nafus 1997, p. 26; Harrington et
al. 2012, in litt.; Rubinoff and Haines 2012, in litt.; Rubinoff, in
litt. 2013). However, despite recent surveys (2011-2013) on Rota,
Tinian, and Saipan, the Mariana eight-spot butterfly is currently known
only from the island of Guam (Schreiner and Nafus 1996, p. 2; Schreiner
and Nafus 1997, p. 26; Rubinoff and Haines 2012, in litt.; Rubinoff
2013, in litt. 2013). There are 11 known populations of the Mariana
eight-spot butterfly on Guam (Schreiner and Nafus 1996, p. 2; Schreiner
and Nafus 1997, p. 26; Rubinoff and Haines 2012, in litt.; Rubinoff
2011, in litt.; Rubinoff 2013, in litt.). Several areas were found that
supported host plants on Saipan in 1995; however, no individuals of the
Mariana eight-spot butterfly were seen, and it may be extirpated on
Saipan (Schreiner and Nafus 1997, p. 26).
In summary, the Mariana eight-spot butterfly has been lost from one
of the two islands where it formerly occurred. This butterfly is
dependent upon two relatively rare host species, both of which are
susceptible to the effects of ungulate grazing. The Mariana eight-spot
butterfly is vulnerable to the impacts of continued habitat loss and
destruction from agriculture, urban development, nonnative animals and
plants, and typhoons. Herbivory of its host plants by nonnative
animals, combined with direct predation by ants and parasitic wasps,
contribute to the decline of the Mariana eight-spot butterfly.
Mariana Wandering Butterfly
The Mariana wandering butterfly (Vagrans egistina), is endemic to
the islands of Guam and Rota in the Mariana archipelago, in the forest
ecosystem. This butterfly was originally named Issoria egistina (Swezey
1942, p. 35). In 1934, Hemming published the genus Vagrans as a
replacement name for the genus Issoria. Schriener and Nafus (1997)
recognize this species as Vagrans egistina, which is the most recent
and accepted taxonomy.
Like most nymphalid butterflies, the Mariana wandering butterfly is
primarily orange and black in coloration. This species is largely black
in appearance with a prominent orange irregular pattern extending from
the forewings to the hindwings. Obvious stripes or rows of spots are
lacking (Schreiner and Nafus 1997, plate 9). The caterpillar larva life
stage of this species is brown in color with black-colored spikes
(Schreiner and Nafus 1996, p. 10).
The Mariana wandering butterflies are known to be good fliers, and
in earlier times, probably existed as a series of meta-populations
(Harrison et al. 1988, p. 360), with considerable movement and
interbreeding between local and stable populations and continued
colonization and extinction in disparate localities. The larvae of this
butterfly feed on the plant species Maytenus thompsonii (luluhut) in
the Celastraceae family, which is endemic to the Mariana Islands
(Swezey 1942, p. 35; Schreiner and Nafus 1996, p. 1). The host plant M.
thompsonii is known to occur within the forest ecosystem on Guam, Rota,
Saipan, and Tinian (Vogt and Williams 2004, p. 121).
Historically, the Mariana wandering butterfly was originally
collected and described from the island of Guam where it was considered
to be rare, but widespread (Swezey 1942, p. 35). The species has not
been observed on Guam since 1979, where it was last collected in Agana.
Currently, it is considered likely extirpated from Guam (Schreiner and
Nafus 1996, pp. 1-2; Rubinoff 2013, in litt.). The Mariana wandering
butterfly was first collected on Rota in the 1980s (Schreiner and Nafus
1996, p. 10). During several 1995 surveys on Rota, it was recorded at
only one location among six different sites surveyed (Schreiner and
Nafus 1996, pp. 1-2). From June through October 2008, extensive surveys
for the Mariana wandering butterfly were conducted on the island of
Tinian under the direction of the Service. While several Maytenus
thompsonii host plant population sites were identified in limestone
forest habitat, no life stages of the Mariana wandering butterfly were
observed (Hawley in litt., 2009, pp. 1-9).
Although considered extirpated from Guam, whether the Mariana
wandering butterfly continues to exist on Rota is unknown, as is its
possible occurrence on other islands where its host plants are found.
Several years of seasonal surveys are needed to determine the status of
this species, but we do know that if it persists, it is likely in very
low numbers as it has not been observed in many years. Any remaining
populations of the Mariana wandering butterfly continue to be at risk
from ongoing habitat loss and destruction by rats and typhoons.
Herbivory of its host plant by nonnative animals, combined with direct
predation by ants and parasitic wasps, contribute to the decline of the
Mariana wandering butterfly.
Rota Blue Damselfly
The Rota blue damselfly (Ischnura luta) is a small damselfly
endemic to the island of Rota and found within the stream ecosystem.
Grouped together with dragonflies in the order Odonata, damselflies
fall within the suborder Zygoptera. The Rota blue damselfly belongs to
the family Coenagrionidae, and it is the only known damselfly species
endemic to the Mariana Islands. This species was first described in
2000 (Polhemus et al. 2000, pp. 1-2) based upon specimens collected in
1996. The species is relatively small in size, with males measuring 1.3
in (34 mm) in body length, with forewings and hindwings 0.7 in (18 mm)
and 0.67 in (17 mm) in length, respectively. Both sexes are
predominantly blue in color, particularly the thorax and portions of
the male's abdomen are brilliant, iridescent blue. Both sexes have a
yellow and black head with some yellow coloration on the abdomen.
Females of this species may be distinguished by their slightly smaller
size and somewhat paler blue body color (Polhemus et al. 2000, pp. 1-
8).
Resembling slender dragonflies, damselflies are readily
distinguished by their trait of folding their wings parallel to the
body while at rest rather than holding them out perpendicular to the
body. The general biology of narrow-winged damselflies includes
territorial males that guard areas of habitat where females will lay
eggs (Moore 1983a, p. 89; Polhemus and Asquith 1996, pp. 2-7). During
copulation, and often while the female lays eggs, the male grasps the
female behind the head with terminal abdominal appendages to guard the
female against rival males; thus males and females are frequently seen
flying in tandem. Adult damselflies are predaceous and feed on small
flying insects such as midges and other flies.
The immature larval life stages (naiads) of the vast majority of
damselfly species are aquatic, breathe through flattened abdominal
gills, and are predaceous, feeding on small aquatic invertebrates or
fish (Williams 1936, p. 303). Females lay eggs in submerged aquatic
vegetation or in mats of moss or algae on submerged rocks, and hatching
occurs in about 10 days (Williams 1936, pp. 303, 306, 318; Evenhuis et
al. 1995, p. 18). Naiads may take up to 4 months to mature (Williams
1936, p. 309), after which they crawl out of the water onto rocks or
vegetation to molt into winged adults, typically remaining close to the
aquatic habitat from which they emerged. Adults have only been observed
in association with the single perennial stream on Rota; therefore, we
[[Page 59384]]
believe the larval stage of the Rota blue damselfly is aquatic.
The Rota blue damselfly was only first discovered in April 1996,
when a few individuals were observed and one male and one female
specimen were collected outside the Talakhaya Water Cave (also known as
Sonson Water Cave) located below the Sabana plateau (Polhemus et al.
2000, pp. 1-8; Camacho et al. 1997, p. 4). The size of the population
at the time of discovery was estimated to be small and limited to the
stream area near the mouth of the cave. The primary source of the
stream is springwater emerging at the limestone-basalt interface below
the highly permeable limestone of the Sabana plateau (Polhemus et al.
2000, pp. 1-8; Keel et al. 2011, p. 1). This spring water also serves
as the main source of fresh water supply for the population of Rota
(Polhemus et al. 2000, pp. 1-8; Keel et al. 2011, p. 1). A concrete
collection structure with associated piping has been built into and
surrounding the entrance of the water cave. This catchment system and a
smaller, adjacent catchment deliver approximately 2.7 to 3.8 million
liters-per-day (0.7 to 1 million gallons) of water to Rota's municipal
system (Keel et al. 2011, pp. 29-30) (see ``Stream Ecosystem,'' above,
and Factor E. Other Natural or Manmade Factors Affecting Their
Continued Existence, ``Water Extraction,'' below, for further
discussion).
Eighteen years elapsed between the original discovery of the
species in 1996 and the next known survey for the Rota blue damselfly.
In January 2014, two male specimens were observed flying above a
portion of the stream located at approximately 770 ft (235 m) in
elevation, and below the Talakhaya (Sonson) Water Cave (Richardson
2014, in litt.). No specimens were observed immediately in the vicinity
of the water cave entrance, and no fish were observed in the stream
immediately below the cave entrance (Richardson 2014, in litt.), a
notable observation because many damselfly species endemic to Pacific
islands are known to be susceptible to predation by nonnative fish
species that eat the naiad life stage of the damselfly. Predation by
nonnative fish is a serious threat to the Hawaiian Megalagrion
damselfly naiads (Englund 1999, pp. 235-236). Eggs laid in vegetation
or on rocks in streams hatch in about 10 days and develop into naiads.
Naiads take approximately 4 months to mature before emerging from the
water (Williams 1936, pp. 303, 306, 309, 318).
Fish predation has been an important factor in the evolution of
behavior in damselfly naiads in continental systems (Johnson 1991, p.
8), and damselflies in the wider-ranging Ishnura (as opposed to the
Hawaiian Megalagrion) may have developed avoidance behaviors (Polhemus
2014, pers. comm.). On a survey of the stream (Okgok River, also known
as Babao) fed by the Talakhaya (Sonson) Water Cave, the presence of
four native fish species was noted: The eel Anguilla marmorata, the
mountain gobies Stiphodon elegans and Sicyopus leprurus, and the
flagtail, or mountain bass, Kuhlia rupestris (Camacho et al. 1997, p.
8). Densities of these native fish were low, especially in areas above
the waterfall. Gobies can maneuver in areas of rapidly flowing water by
using ventral fins that are modified to form a sucking disk (Ego 1956,
in litt.). The flagtails were only abundant in the lower reach of the
stream. Freshwater gobies in Hawaii are primarily browsers and bottom
feeders, often eating algae off rocks and boulders, with midges and
worms being their primary food items (Ego 1956, in litt.; Kido et al.
1993, p. 47). It can only be speculated that the Rota blue damselfly
may have adapted its behavior to avoid the benthic feeding habits of
native fish species. The release of aquarium fish into streams and
rivers of Guam is well documented, but currently, no nonnative fish
have been found in the Rota stream (Tibbatts 2014, in litt.).
The Rota blue damselfly appears to be extremely limited in range
and researchers remain perplexed by its absence from other Mariana
Islands (Polhemus et al. 2000, p. 8). Particularly striking is the fact
that it has never been collected on Guam, despite the islands' larger
size and presence of over 100 rivers and streams. The Rota blue
damselfly's population site is afforded some protection from human
impact by its remote and relatively inaccessible location; however, a
reduction or removal of stream flow due to increased interception for
municipal usage, and from lower water quantities resulting from the
effects of climate change, could eliminate the only known population of
the species (See ``Stream Ecosystem,'' above, and Factor E. Other
Natural or Manmade Factors Affecting Their Continued Existence, below,
for further discussion). Introduction of nonnative fish into the stream
could also impact or eliminate the Rota blue damselfly naiads, leading
to its extirpation. In addition, low numbers of individuals result in
loss of vigor and genetic representation and contribute to the decline
of the Rota blue damselfly.
Humped Tree Snail
The humped tree snail (Partula gibba; akaleha), in the Partulidae
family, is endemic to the forest ecosystem on the Mariana Islands of
Guam, Rota, Aguiguan, Saipan, Tinian, Anatahan, Sarigan, Alamagan, and
Pagan. The humped tree snail was first collected on Guam in 1819 by
Quoy and Gaimard during the Freycinet Uranie expedition of 1817-1819
and was once considered the most abundant tree snail on Guam (Crampton
1925, pp. 8, 25, 60). Currently, the humped tree snail is known from
the islands of Guam (Hopper and Smith 1992, p. 81; Smith et al. 2009,
pp. 10, 12, 16), Rota (Smith 1995, p. 1; Bauman 1996, pp. 15, 18),
Saipan (Hadfield 2010, pp. 20-21), Sarigan (Hadfield 2010, p. 21)
Alamagan (Bourquin 2002, p. 30), and Pagan (Hadfield 2010, pp. 8-14),
in the forest ecosystem. The humped tree snail may occur on Aguiguan,
but was not located on a survey by Smith in 2006 (Smith 2013, p. 14).
It is believed that this species is no longer extant on Tinian due to
loss of habitat to agriculture and the introduction of nonnative snails
(Smith 2013, p. 24), and that it is no longer extant on Anatahan due to
volcanic activity in 2003 and 2005 (Kessler 2011, pp. 321, 323).
The shell of the humped tree snail can be left- or right-coiling,
conic-ovate, translucent, and engraved longitudinally with equal lines.
The color ranges from white to brown, and has a pointed apex colored
rose-red, with a milky white suture. Adult snails are from 0.6 to 0.7
in (14 to 18 mm) long, and 0.4 to 0.6 in (10 to 14 mm) wide, with 4 \1/
2\ whorls, the last of which is the largest (Pilsbry 1909-1910 in
Crampton 1925, p. 60; Smith et al. 2009, p. 2). In general, partulid
snails reproduce in less than 1 year, at which time they can produce up
to 18 young each year, and may live up to 5 years. The humped tree
snail is oviviparous (gives birth to live young). They are generally
nocturnal, live on bushes or trees, and feed primarily on dead or
decaying plant material.
The humped tree snail occurs in cool, shaded forest habitat as
observed by Crampton and others (Crampton 1925, pp. 31, 61; Cowie 1992,
pp. 175-176) with high humidity and reduced air movement that prevents
excessive water loss. Crampton (1925, pp. 31, 61) described the habitat
requirements of the partulid trees snails as having ``sufficiently high
and dense growth to provide shade, to conserve moisture, and to effect
the production of a rich humus. Hence the limits to the areas occupied
by Partulae are set by the more
[[Page 59385]]
ultimate ecological conditions which determine the distribution of
suitable vegetation.'' Crampton further notes that the Mariana Islands
partulid tree snails live on subcanopy vegetation and are not found in
high canopy. There are no known natural predators of these snails,
although many of these partulid species are currently preyed on by
alien invertebrates such as flatworms and slugs (Cowie 1992, p. 175).
Following is a brief historical overview of the humped tree snail
in the Mariana archipelago. Crampton (1925, pp. 8, 25, 60) first
observed the humped tree snail on Guam, in at least 39 sites, totaling
more than 3,000 individuals. In 1989, Hopper and Smith (1992, p. 81)
resurveyed 34 of Crampton's 39 sites and did not locate any live
individuals; however, they discovered individuals at a new site not
noted by Crampton. Populations on Guam have since declined from
hundreds to fewer than 50 individuals (Smith et al. 2009, p. 11).
Bauman surveyed Rota and reported finding live humped tree snails at 5
out of 25 former sites (Bauman 1996, pp. 15, 18). The largest of these
populations may have totaled as many as 1,000 snails. However, this
population was located along the main road of Rota and was subsequently
cleared for development (Miller 2007, pers. comm.). Four other
populations on Rota in 2007 were small and totaled fewer than 600
individuals.
The humped tree snail was discovered on Aguiguan in 1952, in six
colonies (biologists often refer to snail populations as ``colonies'')
(Kondo 1970, pp. 75, 81). In 1992, two separate surveys reported snails
were observed at four locations on Aguiguan (Craig and Chandran 1992;
Smith 1995), but by 2008, no live snails were found on this island
(Smith 2013, p. 14). Crampton (1925) was unable to visit Tinian,
although he states that Partulae were known from that island (1925, p.
6). Smith reported finding only very old shells on two surveys (2006
and 2008) of Tinian (Smith 2013, p. 6). On Saipan, Crampton collected
almost 7,000 humped tree snails in 1925 (Crampton 1925, p. 62). By
1991, Smith and Hopper (1994, p. 11) could not find any live snails at
12 sites visited on the island; however, 2 small populations were later
discovered, one in 2002, in the central forest area, and another in a
mangrove wetland in 2010 (Bourquin 2002, in litt.; Hadfield 2010, pp.
20-21).
In 1994, Kurozumi reported approximately 20 individuals from
Anatahan; however, these were possibly extirpated due to violently
destructive volcanic eruptions between 2003 and 2005 (Kessler 2011).
Kurozumi also reported the humped tree snails from Sarigan in 1994, and
the population appears to be increasing as a result of the removal of
ungulates. A survey of Sarigan in 2006 found the healthiest population
in native forest at an elevation of approximately 1,300 ft (400 m)
(Smith 2006 in Martin et al. 2008, p. 8-1). The species was first
reported on Alamagan by Kondo in 1949, with over 50 individuals
collected from wet forest (Easley 1970, p. 87). The populations seem to
have declined on Alamagan by over 70 percent for individuals and
approximately 27 percent for populations since that time (Kurozumi
1994). The humped tree snail was first reported from Pagan by Kondo in
1949 (Easley 1970, p. 87). Populations persist on Pagan although the
same decline is seen here as for Alamagan (Kurozumi 1994).
In summary, populations of the humped tree snail are rapidly
decreasing from initial numbers observed, and with continued habitat
loss and predation by nonnative species, are at risk, with the possible
exception of those on Sarigan, as ungulates have been removed from that
island (see ``Conservation Efforts To Reduce Habitat Destruction,
Modification, or Curtailment of Its Range,'' below). However, predation
by rats remains a threat to the humped tree snail on Sarigan (Kessler
2011, p. 320).
Recent data also suggest that the individuals identified as humped
tree snails on Rota may be a different species (Hadfield 2010, pp. 20-
21). Because these recent findings have not been published, and data on
population numbers and number of individuals has not been determined,
we are still treating the humped tree snail as a single species.
Langford's Tree Snail
Langford's tree snail (Partula langfordi; akaleha), in the
Partulidae family, is endemic to the forest ecosystem of the island of
Aguiguan. Langford's tree snail was first collected and described by
Kondo while working on biological control agents in the early 1950s
(Kondo 1970, 18 pp.). Kondo's taxonomic work is the most recent and
accepted taxonomy for this species. This tree snail has not been
observed in the wild since 1992, when one live individual was observed
on the northwest terrace of the island (Berger et al. 2005, p. 154).
Surveys conducted in 2006 and 2008 revealed only old shells of dead P.
langfordi (Smith 2013, p. 14).
Langford's tree snail has a dextral (to the right or clockwise from
the opening of the shell at the lower right, as opposed to sinistral,
to the left, or counterclockwise) shell, described by Kondo (1970, pp.
75-77) as being ovate-conic and moderately thin. The holotype of this
species has a length of 0.6 in (14 mm), a diameter of 0.4 in (9 mm),
and an aperture length of 0.3 in (8 mm). It has a spire of five whorls
that are slightly convex, with an obtuse apex. Its aperture is oblong-
ovate with the white mouth projections thickened and expanded. It is
buff colored superimposed by maroon.
Although much less studied than related partulid snails from the
Mariana Islands, the biology of Langford's tree snail is believed to be
the same. See ``Humped tree snail (Partula gibba),'' above, for
details.
Historically, Langford's tree snail is known only from the island
of Aguiguan. In the 1970 survey of Aguiguan, it was noted that
Langford's tree snail was collected from an area where it occurred
sympatrically with the humped tree snail (Easely 1970, p. 89). The
mixed populations were not uniformly distributed, but occurred in small
colonies with large unoccupied areas between the colonies. In five of
the sites, the Langford's tree snail outnumbered the humped tree snail
and it appeared that humped tree snails were more numerous and dominant
in the western portion of the site while Langford's tree snails were
dominant in the eastern portion of the site (Kondo 1970, p. 81). Three
other colonies of Langford's tree snail were collected, two on the
north coast and one on the west end of Aguiguan (Kondo 1970, p. 81). A
total of 464 adults were collected from 7 sites (Kondo 1970, p. 81). In
1985, five adult Langford's tree snails were collected from the west
end of the island (Smith 1995). The last survey in which the species
was detected in the wild was conducted in 1992, and one live snail was
observed on the northwest terrace of the island (Smith 1995). Surveys
of Aguiguan in 2006 and 2008 failed to locate any live Langford's tree
snails (Smith 2013, p. 14).
In 1993, the University of Nottingham in England had six young and
four adult Langford's tree snails in captivity. By 1994, two adult
snails remained. Unfortunately, at the end of 1994, the last two
Langford's tree snails died (Pearce-Kelly et al. 1995).
The 2005 Comprehensive Wildlife Conservation Strategy for CNMI
(Division of Fish and Wildlife) (Berger et al. 2005) states that ``all
Partulid snails are selected as a species of special conservation
need'' (p. 153), and that ``[Crampton] found as many as 31 snails on
the underside of a single leaf of caladium'' (p. 155) (demonstrating
that it would be easy to miss a large number
[[Page 59386]]
of snails if that one particular leaf were missed during a survey).
This strategy outlines conservation actions for Langford's tree snail,
including more numerous and intensive surveys, removal of goats from
Aguiguan island, control of nonnative species, and reforestation with
native plants (pp. 158-159). Given that so few surveys have been
conducted on Aguiguan, and only previously surveyed sites were ever
revisited, it is likely Langford's tree snail may be found.
Guam Tree Snail
The Guam tree snail (Partula radiolata; akaleha), in the Partulidae
family, is endemic to the forest ecosystem of Guam. The Guam tree snail
was first collected by Quoy and Gaimard during the French Astrolabe
expedition of 1828 and was initially named Bulimus (Partula) radiolatus
by Pfeiffer in 1846, which he changed to Partula radiolata in 1849
(Crampton 1925, p. 34). Crampton's 1925 taxonomic work is the most
recent and accepted taxonomy for this species.
The shell of the Guam tree snail is pale straw-colored with darker
streaks and brown lines, and has impressed spiral lines. Adult length
is 0.5 to 0.7 in (13 to 18.5 mm), and width is 0.3 to 0.5 in (8 to 12
mm), with five slightly convex whorls (Pilsbry 1909-1910 in Crampton
1925, p. 35; Smith et al. 2008 in Kerr 2013, p. 10). The biology of the
Guam tree snail is very similar to that of the humped tree snail (see
``Humped tree snail (Partula gibba),'' above, for further description).
The Guam tree snail prefers the same cool, shaded forest habitat as the
humped tree snail and Langford's tree snail, described above.
Historically, suitable habitat for the Guam tree snail was widely
available prior to World War II, and included strand vegetation,
forested river borders, and lowland and highland forests (Crampton
1925, pp. 36-37), and Crampton found ``it occurs almost everywhere on
the island where suitable vegetation exists,'' although historical
population numbers are unknown. Crampton (1925, pp. 38-40) found the
Guam tree snail at 37 of 39 sites surveyed on Guam and collected a
total of 2,278 individuals. The actual population sizes were probably
considerably larger since the purpose of Crampton's collections was to
evaluate geographic differences in shell patterns and not to assess
population size. In 1989, Hopper and Smith (1992, p. 78) resurveyed 34
of Crampton's 39 sites on Guam and an additional 13 new sites. They
observed that 9 of the original 34 sites resurveyed supported these
snails; however, the Crampton site identified as having the largest
remaining population of the Guam tree snail (estimated at greater than
500 snails) had been completely eliminated by the combined effects of
land clearing for a residential development and a subsequent series of
typhoons in 1990, 1991, and 1992 (Smith 1995).
Of the 13 new sites surveyed by Hopper and Smith in 1989, 7
supported populations of the Guam tree snail. One of these populations
was eliminated by wildfires that burned into ravine forest occupied by
the snails in 1991 and 1992 (Smith and Hopper 1994). Further surveys by
Smith (1995) revealed five new populations of the Guam tree snail.
According to Smith, by 1995, there were 20 sites that still supported
small populations of the Guam tree snail. Snails were moved from 1 of
these 20 sites to a new location due to the development of a golf
course (Smith 1995). In 2003 an additional small colony (fewer than 100
snails) was found on the U.S. Naval Base (Smith 2006, pers. comm.). A
smaller colony (20 to 25 snails) was found in 2004 along the Lonfit
River (Smith 2006, pers. comm.). Additionally, surveys on the Guam
Naval Magazine located another new population, with shells of tree
snails in abundance on the ground at all locations (Miller 2006, pers.
comm.; JGPO-NavFac 2014 apps, pp. 27, 59). Further surveys of lands
leased by the Navy in 2009 indicated a decline in densities of tree
snails by about half, which was attributed to a loss of native
understory (Smith et al. 2009, pp. 13-14). In 2011, a survey of
Andersen AFB revealed a single colony of Guam tree snail (Joint Region
Marianas (JRM) Integrated Natural Resources Management Plan (INRMP)
Appendices 2012, p. 15).
Populations of the Guam tree snail continue to decline, from first
observations of thousands of individuals by Crampton, down to 20
colonies or fewer today. Continued loss of habitat due to development
and removal of native plants by ungulates contributes to this loss.
Fragile Tree Snail
The fragile tree snail (Samoana fragilis; akaleha), in the
Partulidae family, is known from the forest ecosystems of Guam and
Rota. This species was first described as Partula fragilis by
F[eacute]russac in 1821 (Crampton 1925, p. 30). It is the only species
representing the genus of Samoana in the Mariana Islands. The fragile
tree snail was first collected on Guam in 1819 by Quoy and Gaimard
during the Freycinet Uranie expedition of 1817 to 1819 (Crampton 1925,
p. 30). Crampton's 1925 taxonomic work for this species is the most
recent and accepted taxonomy for this species.
The conical shell of the fragile tree snail is 0.5 to 0.6 in (12 to
16 mm) long, 0.4 to 0.5 in (10 to 12 mm) wide, and is formed by four
whorls that spiral to the right. The common name is derived from the
thin, semi-transparent nature of the shell. The shell has delicate
spiral striations intersected by transverse growth striations. The
background color is buff, tinted by narrow darker marks and whitish
banding that are derived from the internal organs of the animal that
are visible through the shell (Mollendorff 1894 in Crampton 1925, p.
31). The biology and habitat for this partulid tree snail are the same
as those described for the three partulid species described above (see
the ``Humped tree snail (Partula gibba),'' above).
Historically, the fragile tree snail was known from 13 populations
on Guam and 1 population on Rota (Crampton 1925, p. 30; Kondo 1970, pp.
86-87). Easely (1970, p. 86) documented the 1959 discovery of the
fragile tree snail on Rota by R.P. Owen. The same area had been
surveyed just 7 years earlier by Benavente and Kondo, in 1952, but the
fragile tree snail was not observed (Easley 1970, p. 87). In 1989,
Hopper and Smith (1992, p. 78) resurveyed Crampton's original sites
plus 13 more, all on Guam. At that time, they found fragile tree snails
at only six sites. The most recent surveys on Guam for the fragile tree
snail were conducted in 2008 and 2011. Currently, two colonies are
known on Guam (Smith et al., 2009, pp. 7, 13). The original site where
this species was found on Rota was converted to agricultural fields and
no living snails were found there in 1995; however, in 1996, a new
colony was found on Rota in a different location (Bauman 1996, pp. 18,
21).
We lack quantitative estimates for the fragile tree snail (Bauman
1996, p. 21), but Crampton (1925, p. 30) originally described this
species as rare and low in numbers. Available data indicates the number
of known colonies has declined between 1925 and present, from
approximately 14 colonies to only 3 colonies.
In summary, populations of the fragile tree snail are decreasing
from initial numbers observed on Guam and Rota, and are at risk, due to
continued habitat loss and destruction from agriculture, urban
development, nonnative animals and plants, and typhoons. Trade of
shells by collectors, combined with direct predation by rats and
flatworms, also contribute to the decline of the fragile tree snail.
Low numbers of
[[Page 59387]]
individuals contribute to population declines through loss of vigor and
genetic representation.
Summary of Biological Status and Threats Affecting the 23 Species
Proposed for Listing as Endangered or Threatened Species
Section 4 of the Act (16 U.S.C. 1533) and its implementing
regulations (50 CFR part 424) set forth the procedures for adding
species to the Federal Lists of Endangered and Threatened Wildlife and
Plants. A species may be determined to be an endangered or threatened
species due to one or more of the five factors described in section
4(a)(1) of the Act: (A) The present or threatened destruction,
modification, or curtailment of its habitat or range; (B)
overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) the inadequacy of
existing regulatory mechanisms; and (E) other natural or manmade
factors affecting its continued existence. Listing actions may be
warranted based on any of the above threat factors, singly or in
combination. Each of these factors is discussed below.
In considering what factors might constitute threats to a species,
we must look beyond the exposure of the species to a particular factor
to evaluate whether the species may respond to that factor in a way
that causes actual impacts to the species. If there is exposure to a
factor and the species responds negatively, the factor may be a threat
and, during the status review, we attempt to determine how significant
a threat it is. The threat is significant if it drives, or contributes
to, the risk of extinction of the species such that the species
warrants listing as an endangered or threatened species as these terms
are defined in the Act. However, the identification of factors that
could impact a species negatively may not be sufficient to warrant
listing the species under the Act. The information must include
evidence sufficient to show that these factors are operative threats
that act on the species to the point that the species meets the
definition of endangered or threatened under the Act.
If we determine that the level of threat posed to a species by one
or more of the five listing factors is such that the species meets the
definition of either endangered or threatened under section 3 of the
Act, that species may then be proposed for listing as an endangered or
threatened species. The Act defines an endangered species as ``in
danger of extinction throughout all or a significant portion of its
range,'' and a threatened species as ``likely to become an endangered
species within the foreseeable future throughout all or a significant
portion of its range.'' The threats to each of the individual 23
species proposed for listing in this document are summarized in Table
3, and discussed in detail below. Since there are 15 islands in the
Mariana Islands, Table 4 (below) is provided as a supplement to Table
3, to allow the reader to better understand the presence of nonnative
species addressed in this proposed rule that negatively impact the 23
species on an island-by-island basis.
[[Page 59388]]
Table 3--Summary of Primary Threats Identified for Each of the 23 Mariana Islands Species
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Factor A Factor B Factor C Factor D Factor E
------------------------------------------------------------------------------------------------------------------------------------------------------
Predation Predation
Development, Predation and and Inadequate
Species Ecosystem military Non- native Non- Climate Over- and herbivory herbivory existing Species-
training, animals native Fire Typhoons change utilization herbivory by NN by NN regulatory specific
urbanization plants by verte- inverte- mechanisms
ungulates brates brates
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Plants
Bulbophyllum guamense......... FR X R, BTS X X X X ............ ........... ........... S X ..........
Cycas micronesica............. FR X R, P, B, D, X X X X ............ P, D ........... CAS X ORD
BTS
Dendrobium guamense........... FR X R, BTS X X X X ............ ........... ........... S X ..........
Eugenia bryanii............... FR X R, D, BTS X ......... X X ............ D ........... ........... X ..........
Hedyotis megalantha........... SV X R, P, BTS X X X X ............ ........... ........... ........... X REC
Heritiera longipetiolata...... FR X R, P, B, D, X ......... X X ............ P, D ........... ........... X ORD
C, BTS
Maesa walkeri................. FR X R, P, B, D, X X X X ............ ........... ........... ........... X LN
BTS
Nervilia jacksoniae........... FR X P, B, D, R, X X X X ............ ........... ........... S X ..........
BTS
Phyllanthus saffordii......... SV X R, P, BTS X X X X ............ ........... ........... ........... X REC
Psychotria malaspinae......... FR X R, P, B, D, X ......... X X ............ P, D ........... ........... X LN
BTS
Solanum guamense.............. FR X R, P, D, BTS X ......... X X ............ P, D ........... ........... X LN
Tabernae-montana rotensis..... FR X R, P, B, D, X X X X ............ ........... ........... ........... X V
BTS
Tinospora homosepala.......... FR ............ R, BTS X ......... X X ............ ........... ........... ........... X LN
Tuberolabium guamense......... FR X R, BTS X X X X ............ ........... ........... S X LN
Animals
Pacific sheath-tailed bat FR, CA X R, G ......... ......... X X ............ ........... R, BTS, ML ........... X ..........
(Emballonura semicaudata
rotensis)....................
Slevin's skink (Emoia slevini) FR X R, G, P, C ......... ......... X X ............ ........... R, BTS, ML ........... X ..........
Mariana eight spot butterfly FR X R, P, B, D, X ......... X X ............ ........... ........... A, W X ..........
(Hypolimnas octocula BTS
mariannensis)................
Mariana wandering butterfly FR ............ R ......... ......... X X ............ ........... ........... A, W X ..........
(Vagrans egistina)...........
Rota blue damselfly (Ischnura ST X ............ X ......... X X ............ ........... ........... ........... X LN, WE
luta)........................
Humped tree snail (Partula FR X R, G, P, B, X X X X X ........... R F X ..........
gibba)....................... C, D, BTS
Langford's tree snail (Partula FR X R, G X ......... X X X ........... R F X LN
langfordi)...................
Guam tree snail (Partula FR X R, P, B, D, X X X X X ........... ........... F X LN
radiolata)................... BTS
Fragile tree snail (Samoana FR X R, P, B, D, X ......... X X X ........... R F X LN
fragilis).................... BTS
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Factor A = Habitat modification; Factor B = Overutilization; Factor C = Disease or predation; Factor D = Inadequacy of regulatory mechanisms; Factor E = Other Species-specific threats; FR =
Forest; SV = Savanna; ST = Stream; CA = Cave; R = Rats; P = Pigs; B = Water buffalo; D = Deer; C = Cattle; G = Goats; S = Slugs; CAS = Scale; ML = Monitor lizard; A = Ants; W = Parasitic
wasps; F = Manokwar flatworm; BTS = Brown tree snake; REC = Recreational vehicles; ORD = Ordinance; LN = Limited numbers; WE = Water extraction; V = Vandalism.
[[Page 59389]]
Table 4--Nonnative Animal Species That Negatively Impact the 23 Mariana Islands Species Or Their Habitat, by Island
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Species Proposed for Listing that are Subject to
Brown Threats Posed by One or More Nonnative Animal
Island Pigs Goats Cattle Water Deer Rats Monitor Tree Insects and Worms Species on These Islands (see Table 3, above)
Buffalo Lizard Snake ---------------------------------------------------
Plants Animals
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Guam..................... X ......... ......... X X X * X X A, W, F, S, CAS.......... Bulbophyllum guamense, Slevin's skink (on Cocos
Cycas micronesica, Island), Mariana eight-
Dendrobium guamense, spot butterfly, Mariana
Eugenia bryanii, wandering butterfly,
Hedyotis megalantha, Guam tree snail, Humped
Heritiera tree snail.
longipetiolata, Maesa
walkeri, Nervilia
jacksoniae, Phyllanthus
saffordii, Psychotria
malaspinae, Solanum
guamense,
Tabernaemontana
rotensis, Tinospora
homosepala,
Tuberolabium guamense.
Rota..................... ......... ......... ......... ......... X X * X ......... A, W, F, S, CAS.......... Bulbophyllum guamense, Mariana wandering
Cycas micronesica, butterfly, Rota blue
Dendrobium guamense, damselfly, Humped tree
Maesa walkeri, Nervilia snail, Fragile tree
jacksoniae, snail.
Tabernaemontana
rotensis, Tuberolabium
guamense.
Aguiguan................. ......... X ......... ......... ......... X * X ......... F........................ ........................ Pacific sheath-tailed
bat, Humped tree snail,
Langford's tree snail.
Tinian................... ......... ......... X ......... ......... X * X ......... F........................ Heritiera longipetiolata ........................
Saipan................... ......... ......... ......... ......... ......... X * X ** X A, W, F, S............... Dendrobium guamense, Mariana eight-spot
Heritiera butterfly, Humped tree
longipetiolata. snail.
Farallon de Medinilla.... ......... ......... ......... ......... ......... X ......... ......... ......................... ........................ ........................
Anatahan................. ......... ......... ......... ......... ......... X * X ......... ......................... ........................ Humped tree snail.
Sarigan.................. ......... ......... ......... ......... ......... X * X ......... F........................ ........................ Slevin's skink, Humped
tree snail.
Guguan................... ......... ......... ......... ......... ......... X ......... ......... F........................ ........................ Slevin's skink.
Alamagan................. X X X ......... ......... X * X ......... F........................ ........................ Slevin's skink, Humped
tree snail.
Pagan.................... X X X ......... ......... X * X ......... F........................ ........................ Slevin's skink, Humped
tree snail.
Agrihan.................. X X ......... ......... ......... X * X ......... ......................... ........................ ........................
Asuncion................. ......... ......... ......... ......... ......... X ......... ......... ......................... ........................ Slevin's skink.
Maug..................... ......... ......... ......... ......... ......... X ......... ......... ......................... ........................ ........................
Uracas................... ......... ......... ......... ......... ......... X ......... ......... ......................... ........................ ........................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
A = Ants
W = Parasitic wasp
F = Manokwar flatworm
S = Slugs
CAS = Scale
* Animals only
** Confirmed sightings of BTS have occurred on Saipan; however no established populations have been documented.
[[Page 59390]]
Methodology
Scientific research directed toward each of the species proposed
for listing is limited because of their rarity and the challenging
logistics associated with conducting field work in the Mariana Islands
(i.e., areas are typically remote, difficult to access and work in, and
expensive to survey in a comprehensive manner). However, there is
information available on many of the threats that act on Mariana Island
ecosystems, and, for some ecosystems, these threats are well studied
and understood. Each of the native species that occur in the Mariana
Islands ecosystems suffers from exposure to these threats to differing
degrees, because each species that depends upon a shared ecosystem
requires many of the same physical and biological features and the
successful functioning of their specific ecosystem to survive.
Therefore, for the purposes of this proposed rule, our assumption is
that the threats that act at the ecosystem level also act on each of
the species that depend upon those ecosystems. In addition, in some
cases we have identified species-specific threats--threats that affect
a particular species or subset of species within a shared ecosystem--
such as predation of tree snails by nonnative invertebrates. The
species discussed in this proposed rule, which are dependent on the
native ecosystems that are affected by these threats, have in turn
shown declines in either number of individuals, number of occurrences,
or changes in species abundance and species composition. These declines
can reasonably be attributed directly or indirectly to the threats
discussed below (by indirectly, we mean that where there are threats to
the ecosystem that negatively affect the ecosystem, the species in that
ecosystem that depend upon it for survival are negatively affected as
well).
The following constitutes a list of ecosystem-scale threats that
affect the species proposed for listing in the four described
ecosystems on the Mariana Islands:
(1) Foraging and trampling of native plants by feral pigs (Sus
scrofa), goats (Capra hircus), cattle (Bos taurus), water buffalo
(Bubalus bubalis), and Philippine deer (Cervus mariannus), which can
result in severe erosion of watersheds (Cuddihy and Stone 1990, p. 63;
Berger et al. 2005, pp. 42, 44, 138, 156-157; CNMI-SWARS 2010, pp. 9-
10; Kessler 2011, pp. 320-324). Foraging and trampling events
destabilize soils that support native plant communities, bury or damage
native plants, and have adverse effects on water quality due to runoff
over exposed soils (Cuddihy and Stone 1990, p. 63; Berger et al. 2005,
pp. 42, 44, 138, 156-157; CNMI-SWARS 2010, pp. 9-10; Kessler 2011, p.
323).
(2) Ungulate destruction of seeds and seedlings of native plant
species through foraging and trampling facilitates the conversion of
disturbed areas from native to nonnative vegetative communities
(Cuddihy and Stone 1990, p. 65).
(3) Disturbance of soils by feral pigs from rooting can create
fertile seedbeds for alien plants, some of them spread by ingestion and
excretion by pigs (Cuddihy and Stone 1990, p. 65; Kessler 2011, pp.
320, 323).
(4) Increased nutrient availability as a result of pigs rooting in
nitrogen-poor soils, which facilitates establishment of alien weeds.
Introduced vertebrates are known to enhance the germination of alien
plants through seed scarification in digestive tracts or through
rooting and fertilization with feces of potential seedbeds (Stone 1985,
p. 253). In addition, alien weeds are more adapted to nutrient-rich
soils than native plants (Cuddihy and Stone 1990, p. 65), and rooting
activity creates open areas in forests, allowing alien species to
completely replace native stands.
(5) Rodent damage to plant propagules, seedlings, or native trees,
which changes forest composition and structure (Cuddihy and Stone 1990,
p. 67).
(6) Feeding or defoliation of native plants by nonnative insects,
which can reduce geographic ranges of some species, because the damage
caused by these insects weakens the plants, making them more
susceptible to disease or other predators and herbivores (Cuddihy and
Stone 1990, p. 71).
(7) Nonnative insect predation on native insects, which affects
native plant species by preventing pollination and seed set and
dispersal, and can directly kill native insects (Cuddihy and Stone
1990, p. 71).
(8) Nonnative animal (rat, snakes, and monitor lizard) predation on
native birds, tree snails, bats, and skinks, causes island extirpations
or extinctions, in addition to altering seed dispersal of native plants
(Cuddihy and Stone 1990, pp. 72-73).
Each of the above threats is discussed in more detail below, and
summarized above in Table 3. The most-often cited effects of nonnative
plants on native plant species are competition and displacement.
Competition may be for water, light, or nutrients, or it may involve
allelopathy (chemical inhibition of growth of other plants). Alien
plants may displace native species of plants by preventing their
reproduction, usually by shading and taking up available sites for
seedling establishment. Alien plant invasions may also alter entire
ecosystems by forming monotypic stands, changing fire characteristics
of native communities, altering soil-water regimes, changing nutrient
cycling, or encouraging other nonnative organisms (Smith 1989, p. 62;
Vitousek et al. 1987, pp. 224-227).
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
Habitat Destruction and Modification by Development, Military Training,
and Urbanization
The consequences of past land use practices, such as agricultural
or urban development, have resulted in little or no native vegetation
remaining throughout the inhabited islands of the Mariana archipelago,
largely impacting the forest, savanna, stream, and cave ecosystems
(Steadman 1990, pp. 207-215; Steadman 1995, pp. 1123-1131; Fritts and
Rodda 1998, pp. 119-120; Critical Ecosystem Partnership Fund 2007, pp.
i-viii, 1-127). Areas once used for agriculture by the Chamorro are now
being converted into residential areas, left fallow, or are being
burned by hunters to attract deer (GDAWR 2006, p. 30; Boland 2014, in
litt.). Guam's projected population increase by 2040 to 230,000 is an
increase of almost 70 percent from that in 2010 (World Population
Review 2014, in litt.). CNMI's current population of a little over
51,000 is a decrease from that in 2010, due to collapse of the local
garment industry (Eugenio 2009, in litt.). Although the final numbers
are not yet known, the planned military relocation to Guam and Tinian
will add a large number of Marines and their dependents to the local
population, with a concurrent introduction of support staff and
development of infrastructure, and increased use of resources such as
water (Berger et al. 2005, p. 347; JGPO-NavFac, Pacific 2010a, p. ES-
1).
The military buildup on Guam was originally valued in excess of $10
billion (2.5 times the size of the current Guam economy), and was
planned to take place over 4 years (Guam Economic Development Authority
2011, p. 58). The scope of the relocation of personnel has decreased
since this estimate in 2011, but will still greatly affect
infrastructure and resource needs (JGPO-NavFac, Pacific 2014, p. ES
3.1). The currently preferred alternative sites on Guam for relocation
of personnel and for live-fire training include Naval Computer and
Telecommunications
[[Page 59391]]
Station Finegayan, Andersen South, Orote Point, Pati Point, Navy
Barrigada, and Naval Magazine areas, where, in total, 18 of the 23
species or their habitat are known to occur (13 of the 14 plants:
Bulbophyllum guamense, Cycas micronesica, Dendrobium guamense, Eugenia
bryanii, Hedyotis megalantha, Heritiera longipetiolata, Maesa walkeri,
Nervilia jacksoniae, Phyllanthus saffordi, Psychotria malaspinae,
Solanum guamense, Tabernaemontana rotensis, and Tuberolabium guamense;
and 5 of the 9 animals: the Mariana eight-spot butterfly, the Mariana
wandering butterfly, the Guam tree snail, the humped tree snail, and
the fragile tree snail), and additionally includes the host plants
Procris pendunculata and Elatostema calcareum for the Mariana eight-
spot butterfly and the host plant Maytenus thompsonii for the Mariana
wandering butterfly.
The inhabited island of Tinian and the uninhabited island of Pagan
are planned to be used for military training with live-fire weapons and
presence of military personnel. The northern two-thirds of Tinian are
leased by DOD, and the development of these lands and effects from
live-fire training will directly impact the trees Heritiera
longipetiolata (on Tinian) and Cycas micronesica (on Pagan) and their
habitat in the forest ecosystem. Pagan is currently occupied by
Slevin's skink and the humped tree snail, and is historical habitat of
Bulbophyllum guamense, all of which will be negatively impacted by
direct destruction by live-fire weapons or possible wildfires caused by
them and by trampling and destruction by military personnel.
Rota's land is under transition from public to private ownership,
and the flat or lower-sloped areas comprising 66 percent of the island
is expected to be privately owned (National Park Service 2005 in
National Oceanic and Atmospheric Administration (NOAA) 2012, p. 273).
Rota already has 7 hotels, and tourism is the island's principal
economic industry. If Rota's large central forested areas are
developed, only the remaining cliffs or steep slopes would contain
undisturbed native forest (National Park Service 2005 in NOAA 2012, p.
273). Continued development on Rota will cause an increase of water
use, and will impact the Talakhaya Springs and the streams fed by the
springs. Specifically, dewatering of the streams on Rota could lead to
elimination of the only known population of the Rota blue damselfly
(see ``Water Extraction,'' below). Additionally, development around and
within forested areas on Rota will also directly impact the forest
habitat and individuals of Bulbophyllum guamense, Cycas micronesica,
Dendrobium guamense, Maesa walkeri, Nervilia jacksoniae,
Tabernaemontana rotensis, and Tuberolabium guamense; and the habitat
and host plants of the Mariana wandering butterfly, and the humped tree
snail and fragile tree snail.
Other urban development (primarily involving housing development)
will further impact the ecosystems that support native species. On
Guam, a housing development is proposed for the Sigua highlands, where
two of the plant species proposed for listing as endangered (Hedyotis
megalantha and Phyllanthus saffordii) are known to occur (Kelman 2013,
in litt.). In addition, the island of Aguiguan is proposed to be
developed as an ecotourism resort (Eugenio 2013, in litt.). If
developed, this ecotourism resort will negatively impact the forest and
cave ecosystems that support three of the animals proposed for listing
as endangered (the Pacific sheath-tailed bat, the humped tree snail,
and Langford's tree snail), by causing destruction of the forest
ecosystem (and associated food sources for the Pacific sheath-tailed
bat) for development of tourist facilities for transportation and
accommodation, by associated introduction of nonnative predators and
herbivores, and by causing direct disturbance by visitation of caves.
The total land area for all of the northern islands (within these
species' current and historical range) is only 62 mi\2\ (160 km\2\),
and 44 mi\2\ (114 km\2\) of this land area is on islands with volcanic
activity, which could impact the species and their habitat. The larger
land area on the southern islands (332 mi\2\ (857 km\2\)), within these
species' current and historical range, is undergoing increased human
use, as described above.
In summary, development, military training, urbanization (GDAWR
2006, p. 69), and the associated destruction or degradation of habitat
through loss of forest and savanna areas, disturbance of caves, and
dewatering of streams, are serious threats to 13 of the 14 plants
(Bulbophyllum guamense, Cycas micronesica, Dendrobium guamense, Eugenia
bryanii, Hedyotis megalantha, Heritiera longipetiolata, Maesa walkeri,
Nervilia jacksoniae, Phyllanthus saffordii, Psychotria malaspinae,
Solanum guamense, Tabernaemontana rotensis, and Tuberolabium guamense),
and to 8 of the 9 animals (the Pacific sheath-tailed bat, Slevin's
skink, the Mariana eight-spot butterfly, the Rota blue damselfly, the
Guam tree snail, the humped tree snail, Langford's tree snail, and the
fragile tree snail) that are dependent on these ecosystems. We do not
have sufficient information specific to 2 of the 23 species, Tinospora
homosepala and the Mariana wandering butterfly, that would lead us to
conclude that habitat loss as a result of development, military
training, or urbanization is a threat to these species. For a more
thorough discussion of previous occupations and current U.S. military
activities, see ``Historical and Ongoing Human Impact,'' above.
Habitat Destruction and Modification by Nonnative Animals
Animal species introduced by humans, either intentionally or
accidentally, are responsible for some of the greatest negative impacts
to the four Mariana Islands ecosystems described here (Stone 1970, pp.
14, 32; Intoh 1986 in Conry 1988, p. 26; Fritts and Rodda 1998, p.
130). Although there are numerous reports of myriad introduced animal
species that have negatively impacted the four described Mariana
Islands ecosystems, ranging from ungulates to insects (including such
diverse animals as the musk shrew (Suncus murinus), dogs (Canis lupis
familiaris), cats, and black drongoes (birds; Dicrurus macroercus)), we
have focused our efforts here on the negative impacts of those species
that impose the greatest harmful effects on the four ecosystems (see
Table 3). In addition, we address the compounding effects on these
ecosystems that arise when the pressure of two or more individual
negative impacts is greater than the sum of their parts (i.e.,
synergistic effects). Below we discuss the negative impacts of various
nonnative animals, including feral pigs, goats, cattle, and water
buffalo, as well as Philippine deer, rats, and the brown tree snake
(BTS) (Boiga irregularis), which impose the greatest adverse impacts on
one or more of the 4 described Mariana Islands ecosystems (forest,
savanna, stream, and cave) that support the 23 species proposed for
listing here (Stone 1970, pp. 14, 32; Intoh 1986 in Conry 1988, p. 26;
Fritts and Rodda 1998, pp. 130-133; Berger et al. 2005, pp. 42, 44,
138, 156-157; CNMI-SWARS 2010, pp. 7, 24). Because most of the islands
in the Mariana archipelago are small (Guam being the largest), the
negative impacts associated with a destructive nonnative animal species
affect the entire island. The mild climate of the islands, combined
with the lack of competitors or predators, has led to the successful
establishment of large populations of these introduced animals, to the
detriment of the native Mariana Island species and ecosystems.
[[Page 59392]]
These effects are discussed in more detail, below.
Habitat Destruction and Modification by Introduced Ungulates
Like most oceanic islands, the Mariana Islands, and greater
Micronesia, did not support indigenous populations of terrestrial
mammalian herbivores prior to human colonization (Wiles et al. 1999, p.
194). Although agriculture and land use by the Chamorro clearly altered
the landscape and composition of native biota in the Mariana Islands,
starting over 3,500 years ago (Perry and Morton 1999, p. 126; Steadman
1995, pp. 1,126-1,127), impacts to the native species and ecosystems of
the Marianas accelerated following the arrival of Magellan in the 1500s
(Pregill 1998, p. 66; Perry and Morton 1999, pp. 126-127). The Spanish
and subsequent explorers intentionally introduced pigs, cattle, goats,
water buffalo, and Philippine deer to serve as food sources (Fosberg
1960, p. 54; Conry 1988, pp. 26-28). The isolation of the Mariana
Islands allowed plant species to evolve without defenses to browsing
and grazing animals, such as secondary metabolites and spines, making
them highly susceptible to herbivory (Bowen and Van Vuren 1997, p.
1,249; Wiles et al. 1999, p. 194). Introduced mammals have profoundly
influenced many insular ecosystems around the globe through alteration
of the physical environment, culminating in the decline and loss of
native biota (Stone 1970, pp. 14, 32; Scowcroft and Giffin 1983 in
Wiles et al. 1999, p. 194; Stone 1985, pp. 251, 253-263; Campbell and
Donlan 2004, pp. 1,363, 1,365), including the Mariana Islands
ecosystems (Conry 1988, pp. 27-28; Mueller-Dombois and Fosberg 1998,
pp. 250-252, 264; Berger et al. 2005, pp. 42, 44, 138, 156-157; CNMI-
SWARS 2010, pp. 7, 24).
The presence of alien mammals is considered one of the primary
factors underlying the alteration and degradation of native plant
communities and habitats on the Mariana Islands. The destruction or
degradation of habitat due to nonnative ungulates, including pigs,
goats, cattle, water buffalo, and deer, is currently a threat to 17 of
the proposed species in 2 of the 4 ecosystems (forest and savanna) on 7
of the 15 Mariana Islands (Guam, Rota, Aguiguan, Tinian, Alamagan,
Pagan, and Agrihan). Habitat degradation or destruction by ungulates is
a threat to 10 of the 14 plant species (Cycas micronesica, Eugenia
bryanii, Hedyotis megalantha, Heritiera longipetiolata, Maesa walkeri,
Nervilia jacksoniae, Phyllanthus saffordii, Psychotria malaspinae,
Solanum guamense, and Tabernaemontana rotensis), and 7 of the 9 animal
species (the Pacific sheath-tailed bat, Slevin's skink, the Mariana
eight-spot butterfly, the Guam tree snail, the humped tree snail,
Langford's tree snail, and the fragile tree snail) proposed for listing
(Table 3) (Stone 1970, pp. 14, 32; Perlman and Wood 1994, pp. 135-136.;
Fritts and Rodda 1998, pp. 130-133; Mueller-Dombois and Fosberg 1998,
p. 250; Perry and Morton 1999, pp. 126-127; Wiles and Johnson 2004, p.
586; Vogt and Williams 2004, pp. 82-89; Berger et al. 2005, pp. 42, 44,
138, 156-157; CNMI-SWARS 2010, pp. 7, 24; Pratt 2011, pp. 2, 36; Cook
2012, in litt.; Rogers 2012, in litt.; Rubinoff and Haines 2012, in
litt.; Gawel 2014, in litt.; Marler 2014, in litt.). The three
epiphytic orchids (Bulbophyllum guamense, Dendrobium guamense, and
Tuberolabium guamense), the vine Tinospora homosepala, the Mariana
wandering butterfly and its host plant Maytenus thompsonii, and the
Rota blue damselfly are not reported to be vulnerable to habitat
modification and destruction caused by nonnative ungulates.
Pigs--The destruction or degradation of habitat due to nonnative
feral pigs is currently a threat in 2 (forest and savanna) of the 4
Mariana Islands ecosystems and their associated species on 4 of the 15
islands (Guam, Alamagan, Pagan, and Agrihan) (Berger et al. 2005, pp.
37-38, 40-44, 51, 95, 114; CNMI-SWARS 2010, p. 15; Kessler 2011, pp.
320, 323; Pratt 2011, pp. 2, 36). Pigs are present on other islands in
the archipelago not noted above (i.e., Rota, Saipan, and Tinian);
however, they are present in very low numbers, primarily on farms and,
therefore, not considered a threat on these islands at this time.
Feral pigs are known to cause deleterious impacts to ecosystem
processes and functions throughout their worldwide distribution (Aplet
et al. 1991, p. 56; Anderson and Stone 1993, p. 201; Campbell and Long
2009, p. 2,319). Feral pigs are extremely destructive and have both
direct and indirect impacts on native plant communities. While rooting
in the earth in search of invertebrates and plant material, pigs
directly impact native plants by disturbing and destroying vegetative
cover, and trampling plants and seedlings. It has been estimated that
at a conservative rooting rate of 2 square yards (yd\2\) (1.7 m\2\) per
minute, with only 4 hours of foraging a day, a single pig could disturb
over 1,600 yd\2\ (1,340 m\2\) (or approximately 0.3 ac, or 0.1 ha) of
groundcover per week (Anderson et al. 2007, in litt.).
Pigs may also reduce or eliminate plant regeneration by damaging or
eating seeds and seedlings (further discussion of predation by
nonnative ungulates is provided under Factor C. Disease and Predation,
below). Pigs are a major vector for the establishment and spread of
competing invasive, nonnative plant species by dispersing plant seeds
on their hooves and fur, and in their feces (Diong 1982, pp. 169-170,
196-197), which also serves to fertilize disturbed soil (Siemann et al.
2009, p. 547). In addition, pig rooting and wallowing contributes to
erosion by clearing vegetation and creating large areas of disturbed
soil, especially on slopes (Smith 1985, pp. 190, 192, 196, 200, 204,
230-231; Stone 1985, pp. 254-255, 262-264; Tomich 1986, pp. 120-126;
Cuddihy and Stone 1990, pp. 64-65; Aplet et al. 1991, p. 56; Loope et
al. 1991, pp. 18-19; Gagne and Cuddihy 1999, p. 52; Nogueira-Filho et
al. 2009, p. 3,681; CNMI-SWARS 2010, p. 15; Dunkell et al. 2011, pp.
175-177; Kessler 2011, pp. 320, 323). Erosion, resulting from rooting
and trampling by pigs, impacts native plant communities by contributing
to watershed degradation and alteration of plant nutrient status, as
well as causing direct damage to individual plants from landslides
(Berger et al. 2005, pp. 42-44; Vitousek et al. 2009, pp. 3074-3086;
Chan-Halbrendt et al. 2010, p. 251; Kessler 2011, pp. 320-324).
In the Hawaiian Islands, pigs have been described as the most
pervasive and disruptive nonnative influence on the unique native
forests, and are widely recognized as one of the greatest current
threats to Hawaii's forest ecosystems (Aplet et al. 1991, p. 56;
Anderson and Stone 1993, p. 195). The negative impacts from pig rooting
and wallowing described above negatively affect 2 of the 4 described
ecosystems (forest and savanna), and 14 of the 23 species proposed for
listing as endangered or threatened (9 plants: Cycas micronesica,
Hedyotis megalantha, Heritiera longipetiolata, Maesa walkeri, Nervilia
jacksoniae, Phyllanthus saffordii, Psychotria malaspinae, Solanum
guamense, and Tabernaemontana rotensis; and 5 animals: Slevin's skink,
the Mariana eight-spot butterfly, and the Guam tree snail, the humped
tree snail, and the fragile tree snail) (Conry 1988, pp. 27-28; Vogt
and Williams 2004, p. 88; Berger et al. 2005, pp. 37-38, 40-44, 51, 95,
114; CNMI-SWARS 2010, p. 15; SWCA 2010, p. 38; Kessler 2011, pp. 320,
323; Pratt 2011, pp. 2, 36; Harrington et al. 2012, in litt.).
Goats--Habitat destruction or degradation of habitat due to
nonnative feral goats is currently a threat to three of the species
proposed for listing in
[[Page 59393]]
two (forest and cave) of the four Mariana Islands ecosystems, on the
islands of Aguiguan, Alamagan, Pagan, and Agrihan (Berger et al. 2005,
pp. 36, 38, 40, 42-47; CNMI-SWARS 2010, p. 15; Kessler 2011, pp. 320-
323; Pratt 2011, pp. 2, 36). Goats are presumably present on other
islands (e.g., Guam and Saipan, and possibly Rota), but these
individuals are primarily on farms and, therefore, are not considered a
threat at this time (Kremer 2013, in litt.). Three of the 23 species
proposed for listing as endangered or threatened species in this rule
(the Pacific sheath-tailed bat, the humped tree snail, and Langford's
tree snail), within the forest and cave ecosystems on the above-
mentioned islands, are negatively affected by feral goats.
The feral goat population on Aguiguan increased from a handful of
animals in 1992 to more than 1,000 in 2002, which led to the general
destruction of the forest ecosystem due to lack of regeneration of
native plants and almost complete loss of understory plants, leaving
only two native plants that are unpalatable, Cynometra ramiflora and
Guamia mariannae (Cruz et al. 2008, p. 243; Wiles and Worthington 2002,
p. 7). In addition, feral goats on Aguiguan have been observed entering
caves for shelter, which disrupts the endangered Mariana swiftlet
colonies and is believed to disturb the Pacific sheath-tailed bat (Cruz
et al. 2008, p. 243; Wiles and Worthington 2002, p. 17). Researchers
found that if caves suitable for bats were occupied by goats, there
were no bats present in the caves (GDAWR 1995, p. 95). Goats are widely
recognized to have almost limitless ranges, and are able to access, and
forage in, extremely rugged terrain (Clarke and Cuddihy 1980, pp. C-19,
C-20; Culliney 1988, p. 336; Cuddihy and Stone 1990, p. 64).
Goats have completely eliminated some plant species from islands
(Mueller-Dombois and Fosberg 1998, p. 250; Atkinson and Atkinson 2000,
p. 21). On Alamagan and Pagan, goat browsing negatively impacts the
habitat that supports the humped tree snail in the forest ecosystem by
altering the essential microclimate, leading to increased desiccation
and disruption of plant decay processes (Mueller-Dombois and Fosberg
1998, p. 250). On Agrihan, goats have destroyed much of the shrubs that
make up the subcanopy, and the herbs in the understory (Ohba 1994, p.
19). In addition, goats eat the seeds and seedlings of one of the
dominant Micronesian (Mariana Islands and Palau) endemic canopy
species, Elaeocarpus joga, preventing its regeneration (Ohba 1994, p.
19; Ritter and Naugle 1999, pp. 275-281). None of the 23 species
addressed in this proposed rule are known to currently occur on
Agrihan; however, this island may be involved in future recovery
efforts for 1 or more of the 23 species, and 2 other listed species,
the Mariana fruit bat and the Micronesian megapode, occur there.
Cattle--Habitat destruction or degradation of habitat by feral
cattle is currently a threat to two species addressed in this proposed
rule (the humped tree snail and the plant Heritiera longipetiolata) in
the forest ecosystem on the islands of Tinian, Alamagan, and Pagan
(Berger et al. 2005, pp. 114, 218; Kessler 2011, p. 320) Cattle grazing
damages the native vegetation and contributes to loss of native plant
species, and also alters the essential microclimate leading to
increased desiccation and disruption of plant decay processes necessary
to support the humped tree snail, which currently occurs on the islands
of Alamagan and Pagan (Mueller-Dombois and Fosberg 1998, p. 261; Pratt
2011, pp. 2, 36; Hadfield 2010, 23 pp.; Berger et al. 2005, pp. 114,
218). Feral cattle eat native vegetation, trample roots and seedlings,
cause erosion, create disturbed areas into which alien plants invade,
and spread seeds of alien plants in their feces and on their bodies.
The forest in areas grazed by cattle degrades to grassland pasture, and
plant cover is reduced for many years following removal of cattle from
an area. Feral cattle also roam Tinian and are reported to negatively
affect habitat across the island by grazing, trampling plants, and
exposing soil, thereby changing the microclimate and composition of
vegetation. This has led to deleterious effects on 1 (Heritiera
longipetiolata) of the 23 species proposed for listing as an endangered
species in this rule and its forest habitat. The Pacific sheath-tailed
bat, and the plants Dendrobium guamense, Solanum guamense, and
Tuberolabium guamense, occurred historically on Tinian.
Water buffalo--Several herds of Asiatic water buffalo or carabao
roam southern Guam and the Naval Magazine area, and cause damage to the
forest and savanna ecosystems that support 10 of the 23 species
proposed for listing as endangered or threatened species (6 plants:
Cycas micronesica, Heritiera longipetiolata, Maesa walkeri, Nervilia
jacksoniae, Psychotria malaspinae, and Tabernaemontana rotensis; 4
animals: the Mariana eight-spot butterfly, the Guam tree snail, the
humped tree snail, and the fragile tree snail) (Conry 1988, pp. 27-28;
Harrington et al. 2012, in litt.). Water buffalo create mud wallows and
trample vegetation (Conry 1988, p. 27). Wallowing pools can cover as
much as 0.3 ac (0.1 ha) and reach a depth of 3 ft (1.0 m) (Conry 1988,
p. 27), and trampling denudes land cover, leaving erosion scars and
slumping (Conry 1988, pp. 27-28). Water buffalo negatively impact the
Mariana eight-spot butterfly by damaging the habitat that supports its
two host plants (Procris pendunculata and Elatostema calcareum).
Although four additional species (the three epiphytic orchids
(Bulbophyllum guamense, Dendrobium guamense, and Tuberolabium
guamense), and the Mariana wandering butterfly and its host plant
Maytenus thompsonii) may occur on the Naval Magazine, these four
species are not as vulnerable to the negative impacts associated with
water buffalo.
Deer--Habitat destruction or degradation due to Philippine deer is
currently a threat to 13 of the proposed species found in 2 of the 4
described Mariana Island ecosystems (forest and savanna) on the islands
of Guam and Rota (Wiles et al. 1999, pp. 198-200). Philippine deer have
caused extensive damage resulting in changes in the forest structure,
including erosion, grazing to the point of clearing the entire
herbaceous understory, consumption of seeds and seedlings preventing
regeneration of native plants and the spread of invasive plant species,
and other physical damage (e.g., trunk rubbing) (Schreiner 1997, pp.
179-180; Wiles et al. 1999, pp. 193-215; Berger et al. 2005, pp. 36,
45-46, 100; CNMI-SWARS 2010, p. 24; JGPO-NavFac, Pacific 2010b, pp. 3-
33; SWCA 2011, pp. 35, 42; Harrington et al. 2012, in litt.). At least
34 native plant species in the forest ecosystem have been documented as
known food of the deer on the islands of Guam and Rota, including: (1)
genera of 5 plant species addressed in this proposed rule (Cycas spp.
(e.g., C. micronesica), Eugenia spp. (e.g., E. bryanii), Heritiera spp.
(e.g., H. longipetiolata), Psychotria spp. (e.g., P. malaspinae), and
Solanum spp. (e.g, S. guamense); and genera of the 2 host plants
Procris spp. and Elatostema spp. that support the Mariana eight-spot
butterfly; (2) several keystone ecosystem species: Artocarpus
mariannensis (dokdok, seeded bread fruit), Discocalyx megacarpa (otot),
Merrilliodendron megacarpum (faniok), Piper spp., Pipturus argenteus,
and Premna obtusifolia (false elder); and (3) the listed species
Serianthes nelsonii (Wiles et al. 1999, pp. 198-200, 203; Rubinoff and
Haines 2012, in litt.). Philippine deer degrade the habitats that
support 12 of the 23 species proposed for listing
[[Page 59394]]
as endangered or threatened species here, in the forest and savanna
ecosystems on the islands of Guam and Rota (8 plants: Cycas
micronesica, Eugenia bryanii, Heritiera longipetiolata, Maesa walkeri,
Nervilia jacksoniae, Psychotria malaspinae, Solanum guamense, and
Tabernaemontana rotensis; and 4 animals: the Mariana eight-spot
butterfly (including the two host plants Procris pendunculata and
Elatostema calcareum), the Guam tree snail, the humped tree snail, the
fragile tree snail).
In summary, the habitats for 17 of the 23 species within all 4
ecosystems (forest, savanna, stream, and cave) identified in this rule
are exposed to ongoing destruction and modification by feral ungulates
(pigs, goats, cattle, and water buffalo), and Philippine deer (10
plants: Cycas micronesica, Eugenia bryanii, Hedyotis megalantha,
Heritiera longipetiolata, Maesa walkeri, Nervilia jacksoniae,
Phyllanthus saffordii, Psychotria malaspinae, Solanum guamense, and
Tabernaemontana rotensis; and 7 animals: the Pacific sheath-tailed bat,
Slevin's skink, the Mariana eight-spot butterfly (and its 2 host plants
Procris pendunculata and Elatostema calcareum), the Guam tree snail,
the humped tree snail, Langford's tree snail, and the fragile tree
snail). The effects of these nonnative animals include (1) the
destruction of vegetative cover and the required microclimate of the 4
tree snails; (2) trampling of plants and seedlings and direct
consumption of native vegetation and the 10 plants and the host plants
for the 2 butterflies; (3) altering the native ecosystems that provide
habitat for the 10 plants and 7 animals by soil disturbance leading to
erosion and sedimentation; (4) dispersal of alien plant seeds on hooves
and coats and in feces, which contributes to invasion and alteration of
ecosystems required by the 10 plants and 7 animals; (5) alteration of
soil nitrogen availability, and creation of open areas conducive to
further invasion of native ecosystems by nonnative pest plant species;
and (6) alteration of food availability for the Pacific sheath-tailed
bat by destruction of native forest and the associated insect prey. All
of these impacts lead to the subsequent conversion of a plant community
dominated by native species to one dominated by nonnative species (see
``Habitat Destruction and Modification by Nonnative Plants,'' below).
In addition, because these nonnative animals inhabit terrain that is
often steep and rugged (Cuddihy and Stone 1990, pp. 64-65; Berger et
al. 2005, pp. 36-38, 40-47, 51, 95, 100, 114, 218), foraging and
trampling contribute to severe erosion of watersheds. Nonnative
ungulates would thus pose a potential threat to the Rota blue
damselfly's stream habitat, if these ungulates were allowed to roam
freely on Rota (Dunkell et al. 2011, p. 192).
Habitat Destruction and Modification by Introduced Small Vertebrates
Rats--Three rat species are found in the Mariana Islands: (1) the
Polynesian rat (Rattus exulans), the only rat found in prehistoric
fossil records; (2) the Norway rat (R. norvegicus); and (3) a putative
new southeast Asian Rattus line, originally thought to be R. diardii
(synonymous with R. tanezumi) (Pages et al. 2010, p. 200; Pages et al.
2013, pp. 1019-1020; Kuroda 1938 in Wiewel et al. 2009, p. 208; Wiewel
et al. 2009, pp. 210, 214-216). One or more of these rat species are
present on all 15 Mariana Islands (Wiewel et al. 2009, pp. 205-222;
Kessler 2011, p. 320). Rats are a threat to the forest and savanna
ecosystems that support the 22 of the 23 species proposed for listing
as endangered or threatened in this proposed rule (all 14 plant species
and 8 of 9 animal species--all except the Rota blue damselfly in the
stream ecosystem) by affecting regeneration of native vegetation,
thereby destroying or eliminating the associated flora and fauna of
these ecosystems.
Rats are recognized as one of the most destructive invasive
vertebrates, causing significant ecological, as well as economic, and
health impacts (Atkinson and Atkinson 2000, pp. 23-24; Cuddihy and
Stone 1990, pp. 68-69). Rats impact native plants by eating fleshy
fruits, seeds, flowers, stems, leaves, roots, and other plant parts
(Atkinson and Atkinson 2000, p. 23), and can seriously affect plant
regeneration. A New Zealand study of rats in native forests has
demonstrated that, over time, differential regeneration of plants, as a
consequence of rat predation, may alter the species composition of
forested areas (Cuddihy and Stone 1990, p. 69). Rats have caused
declines or even the complete elimination of island plant species
(Campbell and Atkinson 1999, in Atkinson and Atkinson 2000, p. 24).
Plants with fleshy fruits are particularly susceptible to rat predation
(Stone 1985, p. 264; Cuddihy and Stone 1990, pp. 67-69).
Rats also impact the faunal composition of ecosystems by predation
or competition with native amphibian, avian, invertebrate, mammalian,
and reptilian species, often resulting in population declines or even
extirpations; disruption of island trophic systems including nutrient
cycling; and by the creation of novel vectors and reservoirs for
diseases and parasites (Pickering and Norris 1996 in Wiewel et al.
2009, p. 205; Chanteau et al. 1998 in Wiewel et al. 2009, p. 205;
Fukami et al. 2006, pp. 1,302-1,303; Towns et al. 2006, pp. 876-877;
Wiewel et al. 2009, p. 205).
Rats are less numerous on Guam compared to Rota, Saipan, and
Tinian, due to the presence of the BTS (see ``Brown Tree Snake,''
below) (Wiewel et al. 2009, p. 210). An inverse relationship has been
observed between rat density and the density of the BTS, as rats are a
food source for the BTS and, therefore, contribute toward its
persistence (Rodda and Savidge 2007, p. 315; Wiewel et al. 2009, p.
218). Rodda et al. (1991, in CNMI DFW 2005, p. 175) suggests that rats
negatively impact native reptile populations, such as Slevin's skink,
by aggressively competing for habitat. Several restoration studies have
shown rapid increases in skink populations after removal of rats (Towns
et al. 2001, pp. 6, 9).
Brown tree snake--The brown tree snake (BTS), native to coastal
eastern Australia and north through Papua New Guinea and Melanesia, was
accidentally introduced to Guam shortly after World War II (Rodda and
Savidge 2007, p. 307). This arboreal, nocturnal snake was first
observed near the Fena Reservoir in the Santa Rita area, and now
occupies all ecosystems on Guam (Rodda and Savidge 2007, p. 314). There
are reported sightings of the BTS on Saipan; however, there are no
known established populations on Saipan at this time (Campbell 2014,
pers. comm.; Phillips 2014, pers. comm.). The BTS is believed
responsible for the extirpation of 13 of Guam's 22 native bird species
(including all but 1 of its native forest bird species), and for
contributing to the elimination of the Mariana fruit bat, the Pacific
sheath-tailed bat, and Slevin's skink populations from the island
(Rodda and Savidge 2007, p. 307).
The loss or severe reduction of so many bird species and other
small native animal species on Guam has ecosystem-wide impacts, since
many of these bird and small animal species were responsible for seed
dispersal and pollination of native plants (Perry and Morton 1999, p.
137; Rodda and Savidge 2007, p. 311; Rogers 2008, in litt.). Some
report that the BTS has eliminated virtually all native seed dispersers
(Fritts and Rodda 1998, p. 129). Field studies have demonstrated that
seed dispersal of selected native plant species (Aglaia mariannensis,
Elaeocarpa joga, and Premna obtusifolia) has declined on Guam as
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compared to neighboring islands (Rota, Saipan, and Tinian), due to BTS
predation on native birds and other small native vertebrate species
(Ritter and Naugle 1999, pp. 275-281; Rogers 2008, in litt.; Rogers
2009, in litt.). Almost three quarters of the native tree species on
Guam were once dependent on birds to eat their fruits and disperse
their seeds (Rogers 2009, in litt.). Detailed studies on the native
tree P. obtusifolia show that seeds handled by birds are twice as
likely to germinate than seeds that fall off the tree and land directly
below on the forest floor (by either simply nicking the seed and
dropping it, or fully digesting the outer seed coat and excreting it in
feces) (Rogers 2009, in litt.). An impact at one trophic level
(elimination of seed dispersers) has cascading effects on other trophic
levels, and can affect ecosystem stability (Perry and Morton 1999, p.
137).
The brown tree snake's elimination of native plant seed dispersers
is an indirect threat that adversely affects 2 of the 4 described
ecosystems (forest and savanna), and the habitat of 18 of the 23
species proposed for listing as endangered or threatened (all 14 plant
species and 4 of the 9 animal species, including the Mariana eight-spot
butterfly, the Guam tree snail, the humped tree snail, and the fragile
tree snail).
Habitat Destruction and Modification by Nonnative Plants
Native vegetation on the Mariana Islands has undergone extreme
alteration because of past and present land management practices,
including ranching, the deliberate introduction of nonnative plants and
animals, agricultural development, military actions, and war (Ohba
1994, pp. 17, 28, 54-69; Mueller-Dombois and Fosberg 1998, p. 242;
Berger et al. 2005, pp. 45, 105, 110, 218, 347, 350; CNMI-SWARS 2010,
pp. 7, 9, 13, 16). Some nonnative plants were brought to the Mariana
Islands by various groups of people, including the Chamorro, for food
or cultural reasons.
The native flora of the Mariana Islands (plant species that were
present before humans arrived) consisted of no more than 500 taxa, 10
percent of which were endemic (species that occur only in the Mariana
Islands). Over 100 plant taxa have been introduced from elsewhere, and
at least one third of these have become pests (i.e., injurious plants)
(Stone 1970, pp. 18-21; Mueller-Dombois and Fosberg 1998, pp. 242-243,
249, 262-263; Costion and Lorence 2012, pp. 51-100). Of these
approximately 30 nonnative pest plant species, at least 9 have altered
the habitat of 20 of the 23 species proposed for listing as endangered
or threatened species (only 3 of the animal species, the Pacific
sheath-tailed bat, the Slevin's skink, and the Mariana wandering
butterfly, are not directly impacted by nonnative plants (see Table
3)).
Nonnative plants degrade native habitat in the Mariana Islands by:
(1) Modifying the availability of light through alterations of the
canopy structure; (2) altering soil-water regimes; (3) modifying
nutrient cycling; (4) altering the fire regime affecting native plant
communities (e.g., successive fires that burn farther and farther into
native habitat, destroying native plants and removing habitat for
native species by altering microclimatic conditions to favor alien
species); and (5) ultimately converting native-dominated plant
communities to nonnative plant communities (Smith 1985, pp. 217-218;
Cuddihy and Stone, 1990, p. 74; Matson 1990, p. 245; D'Antonio and
Vitousek 1992, p. 73; Ohba 1994, pp. 17, 28, 54-69; Vitousek et al.
1997, pp. 6-9; Mueller-Dombois and Fosberg 1998, pp. 242-243, 249, 262-
263; Berger et al. 2005, pp. 45, 105, 110, 218, 347, 350; CNMI-SWARS
2010, pp. 7, 9, 13, 16).
The following list provides a brief description of the nonnative
plants that impose the greatest negative impacts to forest, savanna,
and stream ecosystems and the proposed species that depend on these
ecosystems (all 14 of the plant species and 6 of the animal species,
including the Mariana eight-spot butterfly, Rota blue damselfly, humped
tree snail, Langford's tree snail, Guam tree snail, and fragile tree
snail).
Antigonon leptopus (chain of hearts, Mexican creeper,
coral vine), a perennial vine native to Mexico, has become widespread
throughout the Mariana Islands. This species is a fast-growing,
climbing vine that can reach up to 25 ft (8 m) in length, and smothers
all native plants in its path (University of Florida Center for Aquatic
and Invasive Plants (UF) 2014, in litt.). The fact that this species
can tolerate poor soil and a wide range of light conditions makes this
species a very successful invasive plant (UF 2013, in litt.).
Coccinia grandis (ivy or scarlet gourd), native throughout
Africa and Asia, is an aggressive noxious pantropical weedy vine that
forms dense blankets that smother vegetation, and currently
proliferates on Guam and Saipan (Space and Falanruw 1999, pp. 3, 9-10).
This species is considered the most invasive and serious threat to
forest health by the CNMI DFW (CNMI-SWARS 2010, p. 15). Currently, C.
grandis covers nearly 80 percent of Saipan (CNMI-SWARS 2010, p. 15).
Chromaeolena odorata (Siam weed, bitterbrush, masigsig),
native to Central and South America, is an herbaceous perennial that
forms dense tangled bushes up to 6 ft (2 m) in height, but can grow up
to 20 ft (6 m) as a climber on other plants (Invasive Species
Specialist Group--Global Invasive Species Database (ISSG-GISD) 2006, in
litt.). This species can grow in a wide range of soils and vegetation
types, giving it an advantage over native plants (ISSG-GISD 2006, in
litt.). Dense stands of C. odorata prevent the establishment of native
plant species due to competition and allelopathic (growth inhibition)
effects (ISSG-GISD 2006, in litt.).
Lantana camara (lantana), a malodorous, branched shrub up
to 10 ft (3 m) tall, was brought to the Mariana Islands as an
ornamental plant. Lantana is aggressive, thorny, and forms thickets,
crowding out and preventing the establishment of native plants (Davis
et al. 1992, p. 412; Wagner et al. 1999, p. 1,320).
Leucana leucocephala (tangentangen, koa haole), a shrub
native to the neotropics, is a nitrogen-fixer and an aggressive
competitor that often forms the dominant element of the vegetation
(Geesink et al. 1999, pp. 679-680).
Paspalum conjugatum (Hilo grass, sour grass) is a
perennial grass that occurs in wet habitats and forms a dense ground
cover. Its small, hairy seeds are easily transported on humans and
animals, or are carried by the wind through native forests, where it
establishes and displaces native vegetation (Pace et al. 2000, p. 23;
Motooka et al. 2003; Pacific Islands Ecosystems at Risk 2008).
Pennisetum species are aggressive colonizers that
outcompete most native species by forming widespread, dense, thick
mats. Pennisetum setaceum (fountain grass) has been introduced to Guam
(Space and Falanruw 1999, pp. 3, 5). Fountain grass occurs in dry, open
places; barren lava flows; and cinder fields, is fire-adapted, and
burns swiftly and hot, causing extensive damage to the surrounding
habitat (O'Connor 1999, p. 1,581). On Hawaii Island, fountain grass is
estimated to cover hundreds of thousands of acres and has the ability
to become the dominant component in dry, open places in the Mariana
Islands (O'Connor 1999, p. 1,578; Fox 2011, in litt.). Pennisetum
purpureum and P. polystachyon have been introduced to Guam and Saipan
(Space and Falanruw 1999, pp. 3, 5). Pennisetum purpureum (Napier
grass, elephant grass) is a vigorous grass that produces razor-sharp
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leaves and forms thick clumps up to 13 ft (4 m) that resemble bamboo
(Plantwise 2014, in litt.). Tall, dense thickets of P. purpureum
outcompete and smother native plants, and can dominate fire-adapted
grassland communities (Holm et al. 1979, in Plantwise 2014, in litt.).
Similarly, dense thickets of Pennisetum polystachyon (mission grass)
alter the fire regime and outcompete and smother native plants
(University of Queensland 2011, in litt.).
Triphasia trifolia (limeberry, limoncito), a shade-
tolerant woody shrub native to southeast Asia, Malaysia, and the
Christmas Islands, is an aggressive plant that forms dense, spiny
thickets in the forest understory that smother native plant species and
outcompete them for light and water (CABI 2014-Invasive Species
Compendium Online Database).
Vitex parviflora (small leaved vitex; molave tree,
agalondi), a medium-sized tree up to 35 ft (10 m) native to Indonesia,
Malaysia, and the Philippines, often forms monotypic stands, and can
spread by seeds and pieces of roots and stems. Vitex parviflora forms
thickets that outcompete, prevent recruitment of, and exclude native
plants (Guaminsects 2005, in litt.). Vitex parviflora has greatly
altered native habitats on Guam (SWCA 2010, pp. 36, 67), and is one of
the most dominant trees on the island (WERI-IREI 2014b, in litt.).
Habitat Destruction and Modification by Fire
Fire is a human-exacerbated threat to native species and native
ecosystems throughout the Mariana Islands, particularly on the island
of Guam. Wildfires plague forest and savanna areas on Guam every dry
season despite the island's humid climate, with at least 80 percent of
wildfires resulting from arson (JGPO-NavFac, Pacific 2010b, p. 1-9).
Deer hunters on Guam and Rota frequently create fires in order to lure
deer to new growth for easier hunting (Kremer 2014, in litt.; Boland
2014, in litt.). It is not uncommon for these fires to become wildfires
that spread across large expanses of the savanna ecosystem as well as
into the adjacent forest ecosystem. Between 1979 and 2001, more than
750 fires were reported annually on Guam, burning over 155 mi\2\ (401
km\2\) during this time period (JGPO-NavFac, Pacific 2010b, pp. 1-8).
Six of these 750 fires burned over 1,000 ac (405 hectares (ha)) (JGPO-
NavFac, Pacific 2010b, pp. 1-8). On the island of Rota on the Sabana,
hunters often set fires, which burn into adjacent native forest. Fire
can destroy dormant seeds of native species as well as plants
themselves, even in steep or inaccessible areas. Successive fires that
burn farther and farther into native habitat destroy native plants and
remove habitat for native species by altering microclimate conditions
to those favorable to alien plants. Alien plant species most likely to
be spread as a consequence of fire are those that produce a high fuel
load, are adapted to survive and regenerate after fire, and establish
rapidly in newly burned areas.
Grasses (particularly those that produce mats of dry material or
retain a mass of standing dead leaves) that invade native forests and
shrublands provide fuels that allow fire to burn areas that would not
otherwise easily burn (Fujioka and Fujii 1980 in Cuddihy and Stone
1990, p. 93; D'Antonio and Vitousek 1992, pp. 70, 73-74; Tunison et al.
2002, p. 122). Native woody plants may recover from fire to some
degree, but fire shifts the competitive balance toward alien species
(National Park Service 1989 in Cuddihy and Stone 1990, p. 93). Another
factor that contributes to wildfires on Guam, and other Mariana Islands
with nonnative ungulates, includes land clearing for pasturage and
ranching, which results in fire-prone areas of nonnative grasses and
shrubs (Stone 1970, p. 32; CNMI-SWARS 2010, pp. 7, 20). Further, the
danger of fire increases following intense typhoons, due to large fuel
accumulation (Donnelly 2010, p. 6). Wildfire is a threat to nine plant
species (Bulbophyllum guamense, Cycas micronesica, Dendrobium guamense,
Hedyotis megalantha, Maesa walkeri, Nervilia jacksoniae, Phyllanthus
saffordii, Tabernaemontana rotensis, and Tuberolabium guamense) and two
animal species (the Guam tree snail (Guam) and the humped tree snail
(Guam and Rota)), because individuals of these species occur in the
savanna ecosystem or the forest ecosystem adjacent to the savanna
ecosystem, on southern Guam (i.e., Cetti Watershed area) and on the
Rota Sabana, where fires are common (Grimm 2012, in litt.; Gutierrez
2012, in litt.; Gutierrez 2013, in litt.).
Habitat Destruction and Modification by Typhoons
The Mariana Islands lie in the western North Pacific basin, which
is the world's most prolific typhoon basin, with an annual average of
26 named tropical cyclones between 1951 and 2010, depending on the
database used (Keener et al. 2012, p. 50). Typhoons are seasonal,
occurring more often in the summer, and tend to be more intense during
El Ni[ntilde]o years (Gualdi et al. 2008, pp. 5,205, 5,208, 5,226). The
North Pacific basin has been relatively calm the past decade; however,
between 2002 and 2005, three typhoons (Typhoon Chataan (2002), Typhoon
Tingting (2004), and Typhoon Nabi (2005)) and two super typhoons (Super
Typhoon Pongsona (2002) and Super Typhoon Chaba (2004)) struck the
Mariana Islands (Federal Emergency Management Agency (FEMA) 2014, in
litt.). In the previous 20 years (between 1976 and 1997), only eight
typhoons reached the island chain that caused damage warranting FEMA
assistance (FEMA 2014, in litt.).
Typhoons may cause destruction of native vegetation and open the
native canopy, thus modifying the availability of light, and creating
disturbed areas conducive to invasion by nonnative pest species and
nonnative plant species that compete for space, water, and nutrients,
and alter basic water and nutrient cycling processes. This process
leads to decreased growth and reproduction for all 14 plant species
proposed for listing as endangered or threatened (see Table 3, above),
and for the host plants (Procris pendunculata, Elatostema calcareum,
and Maytenus thompsonii) for the 2 butterfly species addressed in this
proposed rule (Perlman 1992, 9 pp.; Kitayama and Mueller-Dombois 1995,
p. 671). Additionally, typhoons initiate a large pulse in the
accumulation of debris and often trigger landslides with large debris
flows (Lugo 2008, pp. 368, 372), as well as induce defoliation and
wind-thrown trees, which can create conditions favorable to wildfires
or which can result in the direct damage or destruction of individuals
of the 14 plant species addressed in this proposed rule. Further,
typhoon frequency globally may decrease; however, there may be some
regional increases (e.g., in the western north Pacific), with an
increase in the frequency of higher intensity events due to climate
change (Emanuel et al. 2008, p. 361).
Typhoons constitute a threat to the nine animal species proposed
for listing as endangered species in this rule, because the associated
high winds may dislodge larvae, juveniles, or adult individuals from
their host plants, caves, or streams, thereby increasing the likelihood
of mortality caused by lack of essential nutrients for proper
development; increase their exposure to predators (e.g., rats, BTS,
monitor lizards, ants) (see Factor C. Disease and Predation, below);
destroy host plants; open up the canopy and alter the microclimate; or
cause direct physical damage. Damage by subsequent typhoons could
further decrease the remaining native plant-dominated
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habitat areas, and the associated food resources, that support the nine
animal species. For plant and animal species that persist only in low
numbers and restricted ranges, such as the 23 Mariana Islands species
addressed here, natural disasters, such as typhoons, can be
particularly devastating (Mitchell et al. 2005, p. 4-3).
Habitat Destruction and Modification by Climate Change
Our analyses under the Act include consideration of ongoing and
projected changes in climate. The terms ``climate'' and ``climate
change'' are defined by the Intergovernmental Panel on Climate Change
(IPCC). ``Climate'' refers to the mean and variability of different
types of weather conditions over time, with 30 years being a typical
period for such measurements, although shorter or longer periods also
may be used (Le Treut et al. 2007, p. 96). The term ``climate change''
thus refers to a change in the mean or variability of one or more
measures of climate (e.g., temperature or precipitation) that persists
for an extended period, typically decades or longer, whether the change
is due to natural variability, human activity, or both (Le Treut et al.
2007, p. 104). Various types of changes in climate can have direct or
indirect effects on species. These effects may be positive, neutral, or
negative and they may change over time, depending on the species and
other relevant considerations, such as the effects of interactions of
climate with other variables (e.g., habitat fragmentation) (IPCC 2007,
pp. 8-14, 18).
Climate change will be a particular challenge for the conservation
of biodiversity because the introduction and interaction of additional
stressors may push species beyond their ability to survive (Lovejoy
2005, pp. 325-326). The synergistic implications of climate change and
habitat fragmentation are the most threatening facet of climate change
for biodiversity (Hannah et al. 2005, p. 4). The magnitude and
intensity of the impacts of global climate change and increasing
temperatures on native Mariana Island ecosystems are unknown.
Currently, there are no climate change studies that address impacts to
the specific Mariana Island ecosystems discussed here or any of the 23
individual species proposed for listing as endangered or threatened
species that are associated with these ecosystems. There are, however,
climate change studies that address potential changes in the tropical
Pacific on a broader scale.
Based on the best available information, climate change impacts
could lead to the loss of native species that comprise the communities
in which the 23 species occur (Pounds et al. 1999, pp. 611-612; Still
et al. 1999, p. 610; Benning et al. 2002, pp. 14,246-14,248; Allen et
al. 2010, pp. 668-669; Sturrock et al. 2011, p. 144; Towsend et al.
2011, pp. 14-15; Warren 2011, pp. 165-166). In addition, weather regime
changes (droughts, floods, typhoons) will likely result from increased
annual average temperatures related to more frequent El Ni[ntilde]o
episodes as hypothesized for other Pacific Island chains (Giambelluca
et al. 1991, p. iii). Future changes in precipitation and the forecast
of those changes are highly uncertain because they depend, in part, on
how the El Ni[ntilde]o-La Ni[ntilde]a weather cycle (a disruption of
the ocean atmospheric system in the tropical Pacific having important
global consequences for weather and climate) might change (State of
Hawaii 1998, pp. 2-10). The 23 species proposed for listing as
endangered or threatened species may be especially vulnerable to
extinction due to anticipated environmental changes that may result
from global climate change, due to their small population size and
highly restricted ranges. Environmental changes that may affect these
species are expected to include habitat loss or alteration and changes
in disturbance regimes (e.g., storms and typhoons).
Climate Change and Ambient Temperature--The range of global surface
warming since 1979 is 0.16 [deg]C to 0.18 [deg]C per decade (Trenberth
et al. 2007, p. 237). Globally, the annual number of warm nights
increased by about 25 days since 1951, with the greatest increase since
the mid 1970s (Alexander et al. 2006, pp. 7-8). The bulk of the
increase in mean temperature is related to a larger increase in minimum
temperatures compared to the increase in maximum temperatures
(Giambelluca et al. 2008, p. 1). Globally averaged, 2012 ranked as the
eighth or ninth warmest year since records began in the mid- to late
1800s (Lander and Guard 2013, p. S-11).
To date, climate change indicators specific to the Mariana Islands
have not been published; however, data collected on climate change
indicators from the Pacific Region, (e.g., the Hawaiian Islands) show
that, overall, the daily temperature range is decreasing, resulting in
a warmer environment, especially at higher elevations and at night.
Predicted changes associated with increases in temperature include, but
are not limited to, a shift in vegetation zones upslope, shifts in
animal species' ranges, changes in mean precipitation with
unpredictable effects on local environments, increased occurrence of
drought cycles, and increases in the intensity and number of hurricanes
(i.e., typhoons) (Loope and Giambelluca 1998, pp. 514-515; Emanuel et
al. 2008, p. 365; U.S. Global Change Research Program (US-GCRP) 2009,
pp. 145-149, 153; Keener et al. 2010, pp. 25-28; Finucane et al. 2012,
pp. 23-26; Keener et al. 2012, pp. 47-51). It is reasonable to
extrapolate these predictions to the Mariana Islands as climate in this
area is strongly influenced by the phase of ENSO (Lander and Guard
2013, pp. S192-S194). In addition, weather regime changes (e.g.,
droughts, floods, and typhoons) will likely result from increased
annual average temperatures related to more frequent El Ni[ntilde]o
episodes in the Mariana Islands (Keener et al. 2012, pp. 35-37, 47-51),
and elsewhere in the Pacific (Giambelluca et al. 1991, p. iii).
However, despite considerable progress made by expert scientists toward
understanding the impacts of climate change on many of the processes
that contribute to El Ni[ntilde]o variability, it is not possible to
say whether or not El Ni[ntilde]o activity will be affected by climate
change (Collins et al. 2010, p. 391).
Globally, the increasing ambient temperature is creating a plethora
of anticipated and unanticipated environmental changes such as melting
ice caps, decline in annual snow mass, sea-level rise, ocean
acidification, increase in storm frequency and intensity (e.g.,
hurricanes, typhoons, cyclones, and tornadoes), and altered
precipitation patterns that contribute to regional increases in floods,
heat waves, drought, and wildfires that also displace species and alter
or destroy natural ecosystems (Pounds et al. 1999, p. 611; IPCC AR4
2007, p. 48; Marshall et al. 2008, p. 273; US-GCRP 2009, pp. 81-83;
Allen et al. 2010, p. 669). These environmental changes are predicted
to alter species migration patterns, lifecycles, and ecosystem
processes such as nutrient cycles, water availability, and
decomposition (IPCC AR4 2007, p. 48; Pounds et al. 1999, pp. 611-612;
Sturrock et al. 2011, p. 144; Townsend et al. 2011, pp. 14-15; Warren
2011, pp. 221-226). The species extinction rate is predicted to
increase congruent with ambient temperature increase (US-GCRP 2009, pp.
81-82). In the Mariana Islands, these environmental changes associated
with a rise in ambient temperature can directly impact (by loss of
individuals) and indirectly impact (by loss of habitat or food and
sites for reproduction) the 23 species proposed for listing as
endangered or threatened species in this
[[Page 59398]]
rule, and the ecosystems that support them, as discussed above.
Climate Change and Precipitation--As global surface temperature
rises, the evaporation of water vapor increases, resulting in higher
concentrations of water vapor in the atmosphere, further resulting in
altered global precipitation patterns (U.S. National Science and
Technology Council (US-NSTC) 2008, pp. 60-61; US-GCRP 2009, pp. 145-
146). While annual global precipitation has increased over the last 100
years, the combined effect of increases in evaporation and
evapotranspiration is causing land surface drying in some regions
leading to a greater incidence and severity of drought (US-NSTC 2008,
pp. 60-61; US-GCRP 2009, pp. 145-146). Over the past 100 years, most of
the Pacific has experienced an annual decline in precipitation;
however, the western North Pacific (e.g., western Micronesia, including
the Mariana Islands) has experienced a slight increase (up to 14
percent on some islands) (US-NSTC 2008, p. 63; Keener et al. 2010, pp.
53-54). Increases in rain are associated with alterations in faunal
breeding systems and increases in disease prevalence, flooding, and
erosion (Easterling et al. 2000, p. 2073; Harvell et al. 2002, pp.
2,159-2,161; Nearing et al. 2004, pp. 48-49). It should be noted that
although the western North Pacific typically experiences large amounts
of rainfall annually, drought is a serious concern throughout
Micronesia due to limited storage capacity and small groundwater
supplies (Keener et al. 2012, pp. 49, 58, 119). Future changes in
precipitation in the Mariana Islands are uncertain because they depend,
in part, on how the El Ni[ntilde]o-La Ni[ntilde]a weather cycle might
change (State of Hawaii 1998, pp. 2-10). Long periods of decline in
annual precipitation result in a reduction in moisture availability,
loss of wet forest, an increase in drought frequency, and a self-
perpetuating cycle of invasion by nonnative plants, increasing fire-
cycles, and increasing erosion. These impacts may negatively affect the
23 species proposed for listing as endangered or threatened species in
this rule, and the ecosystems that support them.
Climate Change and Typhoons--A typhoon (as a tropical cyclone is
referred to in the Northwest Pacific ocean) is the generic term for a
medium-to large-scale, low-pressure storm system over tropical or
subtropical waters with organized convection (i.e., thunderstorm
activity) and definite cyclonic surface wind circulation
(counterclockwise direction in the Northern Hemisphere) (Holland 1993,
p. 7, NOAA 2011, in litt.). In the north Pacific Ocean, west of the
International Date Line, once a typhoon reaches an intensity of winds
of at least 150 mi per hour (65 m per second), it is classified as a
super typhoon (Neumann 1993, pp. 1-2; NOAA 2011, in litt.). Climate
modeling has projected changes in typhoon frequency and intensity due
to global warming over the next 100 to 200 years (Emanuel et al. 2008,
p. 360, Figure 8; Yu et al. 2010, pp. 1,355-1,356, 1,369-1,370);
however, there are no certain climate model predictions for a change in
the duration of the Pacific tropical cyclone storm season (which
generally runs from May through November) (Collins et al. 2010, p.
396). The high winds and strong storm surges associated with typhoons,
particularly super typhoons, have periodically caused great damage to
the vegetation of the Mariana Islands. The strong winds can injure or
cause death to the 9 animal species and the 14 plant species addressed
in this proposed rule, and negatively impact the ecosystems that
support them (see ``Habitat Destruction and Modification by Typhoons,''
above).
Climate Change and Sea-Level Rise--On a global scale, sea level is
rising as a result of thermal expansion of warming ocean water; the
melting of ice sheets, glaciers, and ice caps; and the addition of
water from terrestrial systems (Climate Institute 2011, in litt.). Sea
level rose at an average rate of 0.1 in (3.1 mm) per year between 1961
and 2003 (IPCC AR4 2007, p. 30), with a predicted increase in 2100 of
1.6 to 4.6 ft (0.5 to 1.4 m) above the 1990 level (Rahmstorf 2007, p.
368). Seven of the 23 species (5 plants: Bulbophyllum guamense, Cycas
micronesica, Dendrobium guamense, Heritiera longipetiolata, and
Nervilia jacksoniae; and 2 animals: the humped tree snail and the
Mariana eight-spot butterfly (indirectly through impacts to its 2 host
plants (Procris pendunculata and Elatostema calcareum)) have
individuals that occur close to the coast in the adjacent forest
ecosystem at or near sea level and may be negatively impacted by sea-
level rise and coastal inundation due to climate change; however, there
is no specific data available on how sea-level rise and coastal
inundation will impact these species.
In summary, increased variability of ambient temperature,
precipitation, typhoons, and sea-level rise and inundation would
provide additional stresses on the 4 ecosystems and each of the 23
associated species because they are highly vulnerable to disturbance
and related invasion of nonnative species. The risk of extinction as a
result of such factors increases when a species' range is restricted,
its habitat decreases, and its population numbers decline (IPCC 2007,
pp. 8-11). In addition, these 23 species may be at a greater risk of
extinction due to the loss of redundancy and resiliency created by
their limited ranges, restricted habitat requirements, small population
sizes, or low numbers of individuals. Therefore, we would expect these
23 species to be particularly vulnerable to projected environmental
impacts that may result from changes in climate and subsequent impacts
to their habitats (Loope and Giambelluca 1998, pp. 504-505; Pounds et
al. 1999, pp. 611-612; Still et al. 1999, p. 610; Benning et al. 2002,
pp. 14,246-14,248; Giambelluca and Luke 2007, pp. 13-15). Based on the
above information, changes in environmental conditions that result from
climate change are likely to negatively impact the 23 species proposed
for listing as endangered or threatened species in this rule, and we do
not anticipate a reduction in this potential threat in the near future.
Conservation Efforts To Reduce Habitat Destruction, Modification, or
Curtailment of Its Range
There are no approved Habitat Conservation Plans, Candidate
Conservation Agreements, or Strategic Habitat Areas that specifically
address these 23 species and threats to their habitat.
In 2012, the Guam Plant Extinction Prevention Program (GPEPP) was
formed to address conservation concerns for a select group of native
Mariana Islands plant species, including three of the plant species
addressed in this proposed rule: Heritiera longipetiolata, Maesa
walkeri, and Psychotria malaspinae. GPEPP is a partnership between the
University of Guam (UOG), multiple Federal agencies (FWS, DOD, and
USDA), Hawaii State Department of Land and Natural Resources, and the
Hawaii Plant Extinction Prevention Program (Hawaii PEPP). The goal of
GPEPP is to prevent the extinction of native Mariana Islands plant
species that have fewer than 200 individuals remaining in the wild on
the island of Guam (GPEPP 2014, in litt.). The group currently has
funding limitations, so is focusing their efforts on tree species. The
program's main objectives are to monitor, collect, survey, manage, and
reintroduce native plant species in the Mariana Islands. They plan to
work with conservation partners to protect wild populations and
preserve genetic material (GPEPP 2014, in litt.).
A conservation project on Rota, administered through the Water and
[[Page 59399]]
Environmental Research Institute of the Western Pacific at the
University of Guam, is aimed to analyze the island's hydrology, with
the ultimate goal of protection of the Sabana Watershed and Talakhaya
Springs (Keel et al. 2007, pp. 5, 22-23). Erosion control,
revegetation, and water source preservation conducted as part of this
project may provide protection to 9 of the 23 species in this proposed
rule that currently or historically occurred on the southern side of
the central plateau of Rota (6 plants: Bulbophyllum guamense, Cycas
micronesica, Dendrobium guamense, Maesa walkeri, Nervilia jacksoniae,
Tuberolabium guamense; 3 animals: the Mariana wandering butterfly, the
Rota blue damselfly, and the humped tree snail).
A FWS Biological Opinion (1998) recommended that the Navy fund
conservation and recovery projects in the Mariana Islands to improve
habitat and population sizes of the federally listed Micronesian
megapode as mitigation for bombing activities on Farallon de Medinilla.
This resulted in the removal of ungulates from Sarigan, which has
improved native habitat that supports two species in this proposed
rule, the humped tree snail and Slevin's skink, by decreasing the
impacts of trampling and browsing on native plants. Sarigan may serve
as a location for recovery of Slevin's skink and the humped tree snail.
Since 1993, the USDA-Wildlife Services' Brown Tree Snake Program in
Guam has been working to prevent the inadvertent spread of the snake to
other locations, and to reduce negative impacts by the brown tree snake
on economic and ecological resources. Experimentation with toxicant
drops to control the brown tree snake is ongoing. The USDA-Wildlife
Services is the lead agency for this work, in cooperation with the
USDA-National Wildlife Research Center, the U.S. Geological Survey,
FWS, and DOD. Results of the toxicant drops are currently under review
(Phillips 2014, in litt.).
Area 50, a 59-ac (24-ha) enclosure on Andersen AFB, containing a
relictual patch of limestone forest, was created to exclude ungulates
and the brown tree snake (Hess and Pratt 2006, p. 2). This enclosure
was maintained for ecosystem and species experimental research. Several
individuals of the tree Tabernaemontana rotensis occur within the
enclosure and would benefit from protection from predators and habitat
disturbance (Hess and Pratt 2006, p. 7); however, researchers found the
enclosure in a state of neglect, and invaded by nonnative plant species
and pigs, with only 20 ac (8 ha) of undisturbed primary forest
remaining by 2006 (Hess and Pratt 2006, p. 24). We are unaware of any
efforts to continue maintenance of this enclosure since that time.
Rota's Department of Fish and Wildlife constructed exclosures for
two occurrences of Tabernaemontana rotensis in the Sabana Conservation
Area, but only one exclosure remains, as the other burned in a fire
(Hess and Pratt 2006, p. 33; 65 FR 35029, June 1, 2000).
The Micronesian Challenge is an organization with the goal of
preserving at least 30 percent of near-shore marine resources and 20
percent of the terrestrial resources across Micronesia by 2020
(Micronesian Challenge 2011, in litt.). The CNMI government is already
attempting to meet this goal by planning to designate conservation
lands within native forest (CNMI-SWARS 2010, p. 30). The Micronesian
Challenge organization has partnered with many national and
international environmental organizations (e.g., Federated States of
Micronesia, The Republic of the Marshall Islands, The Nature
Conservancy, and the New York Botanical Gardens), and focuses on
conservation outreach to native Micronesians and visitors (Micronesian
Challenge 2011, in litt.).
Summary of Habitat Destruction and Modification
The threats to the habitats of each of the 23 Mariana Islands
species are occurring throughout the entire range of each of the
species, except where noted above, with consequent deleterious effects
on individuals and populations of these species. These threats include
land conversion by agriculture and urbanization, habitat destruction
and modification by nonnative animals and plants, fire, natural
disasters, environmental changes resulting from climate change, and
compounded impacts due to the interaction of these threats. While the
conservation measures described above address some threats to the 23
species, due to the pervasive and expansive nature of the threats
resulting in habitat degradation, these measures are insufficient to
eliminate these threats to any of the 23 species addressed in this
proposed rule.
Development and urbanization represents a serious and ongoing
threat to all 23 species because they cause permanent loss and
degradation of habitat. The effects from ungulates are ongoing because
ungulates currently occur in all 4 ecosystems that support the 23
species in this proposed rule. The threat of habitat destruction and
modification posed by introduced ungulates is serious, because they
cause: (1) Trampling and grazing that directly impacts plants,
including 10 of the 14 plant species addressed in this rule, and
impacts the 2 host plants used by the Mariana eight-spot butterfly for
shelter, foraging, and reproduction; (2) increased soil disturbance,
leading to mechanical damage to individuals of 10 of the 14 plant
species, and also the host plants for the Mariana eight-spot butterfly;
(3) creation of open, disturbed areas conducive to weedy plant invasion
and establishment of alien plants from dispersed fruits and seeds,
which results over time in the conversion of a community dominated by
native vegetation to one dominated by nonnative vegetation; and (4)
increased erosion, leading to destabilization of soils that support
native plant communities, elimination of herbaceous understory
vegetation, and creation of disturbed areas into which nonnative plants
invade. The BTS and rats both negatively impact the four ecosystems by
eating native animals that native plants rely on to disperse seeds,
limiting the regenerative capacity of the native forest. These threats
are expected to continue or increase without ungulate control or
eradication.
Nonnative plants represent a serious and ongoing threat to 20 of
the 23 species addressed in this proposed rule (all 14 plant species,
the Mariana eight-spot butterfly, the Rota blue damselfly, and all 4
tree snails) (see Table 3) through habitat destruction and
modification, because they: (1) Adversely impact microhabitat by
modifying the availability of light; (2) alter soil-water regimes; (3)
modify nutrient-cycling processes; (4) alter fire characteristics of
native plant habitat, leading to incursions of fire-tolerant nonnative
plant species into native habitat; (5) outcompete, and possibly
directly inhibit the growth of, native plant species; and (6) create
opportunities for subsequent establishment of nonnative vertebrates and
invertebrates. Each of these threats can convert native-dominated plant
communities to nonnative plant communities (Cuddihy and Stone 1990, p.
74; Vitousek 1992, pp. 33-36). This conversion has negative impacts on
all 14 plant species addressed here, as well as the native plant
species upon which the Mariana eight-spot butterfly and the Rota blue
damselfly depend for essential life-history needs. For example,
nonnative plants that outcompete native plants can destabilize
streambanks, exacerbating the potential for landslides and rockfalls,
in turn dislodging Rota
[[Page 59400]]
blue damselfly eggs and naiads from streams, and also displace or
destroy vegetation used for perching by adults, leaving them more
susceptible to predation.
The threat from fire to 11 of the 23 species in this proposed rule
that depend on the savanna ecosystem and adjacent forest ecosystems (9
plant species: Bulbophyllum guamense, Cycas micronesica, Dendrobium
guamense, Hedyotis megalantha, Maesa walkeri, Nervilia jacksoniae,
Phyllanthus saffordii, Tabernaemontana rotensis, and Tuberolabium
guamense; and 2 animal species: the Guam tree snail and the humped tree
snail) (see Table 3, above) is serious and ongoing because fire damages
and destroys native vegetation, including dormant seeds, seedlings, and
juvenile and adult plants. After a fire, nonnative, invasive plants,
particularly fire-tolerant grasses, outcompete native plants and
inhibit their regeneration (D'Antonio and Vitousek 1992, pp. 70, 73-74;
Tunison et al. 2002, p. 122; Berger et al. 2005, p. 38; CNMI-SWARS
2010, pp. 7, 20; JGPO-NavFac, Pacific 2010b, pp. 4-33). Successive
fires that burn farther and farther into native habitat destroy native
plants and animals, and remove habitat for native species by altering
microclimatic conditions and creating conditions favorable to alien
plants. The threat from fire is unpredictable but increasing in
frequency in the savanna ecosystem that has been invaded by nonnative
fire-prone grasses, and that is subject to abnormally dry to severe
drought conditions.
Natural disasters such as typhoons are a threat to native
terrestrial habitats on the Mariana Islands in all 4 ecosystems
addressed here, and to all 14 plant species identified in this proposed
rule, because they result in direct impacts to ecosystems and
individual plants by opening the forest canopy, modifying available
light, and creating disturbed areas that are conducive to invasion by
nonnative pest plants (Asner and Goldstein 1997, p. 148; Harrington et
al. 1997, pp. 346-347; Berger et al. 2005, pp. 36, 45, 71, 100, 144;
CNMI-SWARS 2010, p. 10; JGPO-NavFac, Pacific 2010b, pp. 1-8). In
addition, typhoons are a threat to the nine animal species in this rule
because strong winds and intense rainfall can kill individual animals,
and can cause direct damage to streams (Polhemus 1993, pp. 86-87). High
winds and torrential rains associated with typhoons can also destroy
the host plants for the two butterfly species, and can dislodge
individual butterflies and their larvae from their host plants and
deposit them on the ground where they may be crushed by falling debris
or eaten by nonnative wasps and ants. In addition, the high winds can
dislodge bats from their caves and cause individual harm or death. The
impacts of typhoons can be particularly devastating to the 23 species
because, as a result of other threats, they now persist in low numbers
or occur in restricted ranges and are therefore less resilient to such
disturbances, rendering them highly vulnerable. Furthermore, a
particularly destructive super typhoon could potentially drive
localized endemic species to extinction in a single event. Typhoons
pose an ongoing threat because they are unpredictable and can occur at
any time.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Plants
We are not aware of any threats to the 14 plant species that would
be attributed to overutilization for commercial, recreational,
scientific, or educational purposes.
Animals
We are not aware of any threats to five of the nine animal species
(the two Mariana butterflies, Pacific sheath-tailed bat, Slevin's
skink, or Rota blue damselfly) addressed in this proposed rule that
would be attributed to overutilization for commercial, recreational,
scientific, or educational purposes. We do have evidence indicating
that collection is a threat to the four tree snail species addressed in
this proposed rule, as discussed below.
Tree Snails--Tree snails can be found around the world in tropical
and subtropical regions and have been valued as collectibles for
centuries. Evidence of tree snail trading among prehistoric Polynesians
was discovered by analysis of the multi-archipelagic distribution of
the Tahitian endemic Partula hyalina and related taxa (Lee et al. 2007,
pp. 2,907, 2,910). In their study, Lee et al. (2007, pp. 2,908-2,910)
found evidence that P. hyalina had been traded as far away as Mangaia
in the Southern Cook Islands, a distance of over 500 mi (805 km). The
endemic Hawaiian tree snails within the family Achatinellidae were
extensively collected for scientific as well as recreational purposes
by Europeans in the 18th to early 20th centuries (Hadfield 1986, p.
322). Historically, tree snails were abundant in the Pacific Islands.
During the 1800s collectors observed 500 to 2,000 snails per tree, and
sometimes collected more than 4,000 snails in several hours (Hadfield
1986, p. 322). Likewise, in the Mariana Islands, Crampton (an early
naturalist in the islands) alone took 2,666 adult Partula gibba snails
from 8 sites on Sapian in just 6 days in 1925 (Crampton 1925, p. 100).
Repeated collections of hundreds to thousands of individuals at a time
by early collectors may have contributed to decreased population sizes
and reduction of reproduction potential due to the removal of potential
breeding adults (Hadfield 1986, p. 327).
The collection of tree snails persists to this day, and the market
for rare tree snails serves as an incentive to collect them. A search
of the Internet (e.g., eBay and Etsy) reveals Web sites that offer
snail shells from more than 100 land and sea snail species (along with
corals and sand) from around the world, including rare and listed
Achatinella and Partulina. These sites encourage collectors by making
statements such as ``These assorted land snail shells from the tropical
regions of the world are great for crafters and decorations for tanks''
and refer to shells with colorful names such as ``rainbow shells from
Haiti'' (http://www.shells-of-aquarius.com/snail-shells.html; https://www.etsy.com/uk/search?q=tree+snail). Concerned citizens alert law
enforcement of Internet sales and notify the public about illegal sales
through personal web blogs (http://bioacoustics.blogspot.com/2012/04/endangered-species-on-ebay.html). Over the past 100 years, Mariana
species of partulid tree snail shells have been made into jewelry and
purses and sold to tourists (Kerr 2013, p. 3). Based on the history of
collection of Pacific island tree snails, the market for Mariana tree
snail shells, and the vulnerability of the small populations of the
humped tree snail, Langford's tree snail, the Guam tree snail, and the
fragile tree snail, we consider collection a threat to the four endemic
Mariana tree snail species proposed for listing as endangered species
in this rule.
Summary of Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
We have no evidence to suggest that overutilization for commercial,
recreational, scientific, or educational purposes poses a threat to any
of the 14 plant species, 2 butterflies, Pacific sheath-tailed bat,
Slevin's skink, or Rota blue damselfly proposed for listing as
endangered or threatened species. We consider the four species of tree
snails vulnerable to the impacts of overutilization due to collection
for trade or market. Based on the history of collection of Pacific tree
snails, the current market for Marianas tree snail
[[Page 59401]]
shells and tree snail shells world-wide, and the inherent vulnerability
of the small populations of the Guam tree snail, the humped tree snail,
Langford's tree snail, and the fragile tree snail to the removal of
breeding adults, we consider collection to pose a serious and ongoing
threat to these species.
Factor C. Disease and Predation
Disease
We are not aware of any threats to the 23 species addressed in the
proposed rule that would be attributable to disease.
Predation and Herbivory
Multiple animal species, ranging from mammals and rodents to
reptiles and insects, are reported to impact 17 of the 23 species
proposed for listing as endangered or threatened species in this rule
by means of predation or herbivory (Table 3). Those species that have
the most direct negative impact on the 23 species include: feral pigs,
Philippine deer, rats, the brown tree snake, monitor lizards, Cuban
slugs (Veronicella cubensis); the manokwari flatworm (Platydemus
manokwari), the cycad aulacaspis scale, ants (Tapinoma minutum,
Technomyrmex albipes, Monomorium floricola, and Solenopsis geminata),
and parasitoid wasps (Telenomus sp. and Ooencyrtus sp.). Data show
these nonnative animals have caused a decline of 17 of the 23 species
(Intoh 1986 in Conry 1988, p. 26; Fritts and Rodda 1998, pp. 130-133).
Although feral goats, cattle, and water buffalo occur on one or more of
the Mariana Islands and are recognized to negatively impact the
ecosystems in which they occur (see Factor A. The Present or Threatened
Destruction, Modification, or Curtailment of Its Habitat or Range,
above), we have no direct evidence that goats, cattle, or water buffalo
browse specifically on any of the 14 plant species addressed in this
proposed rule.
Ungulates
Pigs--Feral pigs are widely recognized to negatively alter
ecosystems (see ``Habitat Destruction and Modification by Introduced
Ungulates,'' above). In addition, feral pigs have been observed to eat
the leaves, fruits, seeds, seedlings, or bark, from 4 of the 14 plant
species proposed for listing as endangered or threatened species in
this rule (Cycas micronesica, Heritiera longipetiolata, Psychotria
malaspinae, and Solanum guamense) in the forest ecosystem (Perlman and
Wood 1994, pp. 135-136; Harrington et al. 2012, in litt.; Rogers 2012,
in litt.; Marler 2013, pers. comm.). Similarly, on other Pacific
islands (e.g., the Hawaiian Islands), pigs are known to eat and fell
plants and remove the bark from a variety of native plant species,
including Clermontia spp., Cyanea spp., Cyrtandra spp., Hedyotis spp.,
Psychotria spp., and Scaevola spp. (Diong 1982, p. 144). In addition,
evidence of pigs feeding on Cycas micronesica has been observed,
hypothesized for the intent to get at grubs (Harrington et al. 2012, in
litt.). Pigs also eat standing living stems of plants, thought to be
for the same intent (Marler 2013, pers. comm.). Feral pigs have been
documented to eat the host plants that support the Mariana eight-spot
butterfly (Procris pendunculata and Elatostema calcareum).
In addition to deer imposing negative impacts on habitat at an
ecosystem scale in the Mariana Islands on which they occur (primarily
Guam and Rota), deer consume leaves, seeds, fruits, and bark of 5 of
the 14 plant species (Cycas micronesica, Eugenia bryanii (deer are
known to consume all Mariana Islands Eugenia spp.), Heritiera
longipetiolata, Psychotria malaspinae, and Solanum guamense), and the 2
host plants for the Mariana eight-spot butterfly (Wiles et al. 1999,
pp. 198-200, 203; Rubinoff and Haines 2012, in litt.).
Other Nonnative Vertebrates
Rats
Rat Predation on Tree Snails--Rats (Rattus spp.) have been
suggested as responsible for the greatest number of animal extinctions
on islands throughout the world, including extinctions of various snail
species (Towns et al. 2006, p. 88). Rats are known to prey upon Pacific
island endemic arboreal snails (Hadfield et al. 1993, p. 621). In the
Waianae mountains of Oahu, Meyer and Shiels (2009, p. 344) found shells
of the endemic Oahu tree snail (Achatinella mustelina) with
characteristic rat damage (e.g., damage to the shell opening and cone
tip), but noted that, since a high proportion of crushed shells could
not reliably be collected in the field, the impact of rat predation on
snail populations may be underestimated. Rat predation on tree snails
has also been observed on the Hawaiian Islands of Lanai (Hobdy 1993, p.
208; Hadfield 2005, in litt, p. 4), Molokai (Hadfield and Saufler 2009,
p. 1,595), and Maui (Hadfield 2006, in litt.). Rat populations on Guam
may be limited by predation by the brown tree snake, thereby limiting
rat predation on native tree snails. Because rats occur in larger
numbers on the Mariana Islands to the north of Guam, rat predation is
considered a threat to the three tree snail species addressed in this
proposed rule that occur on the other Mariana Islands (the humped tree
snail on Rota, Aguiguan, Saipan, Sarigan, Alamagan, and Pagan; the
fragile tree snail on Rota; and Langford's tree snail on Aguiguan).
Rat Predation on Bats--Rats may prey on the Pacific sheath-tailed
bat, proposed for listing as endangered. Rats are omnivores and are
opportunistic feeders. Rats have a widely varied diet consisting of
nuts, seeds, grains, vegetables, fruits, insects, worms, snails, eggs,
frogs, fish, reptiles, birds, and mammals (Fellers 2000, p. 525; GISD
2014, in litt.). Rats occur on Aguiguan, the only island on which the
Pacific sheath-tailed bat is known to roost (Berger et al. 2005, p.
144). Rats are predators on young bats at roosts (that are nonvolant,
i.e., have not yet developed the ability to fly) (Wiles et al. 2011, p.
306). The black rat was determined to be the primary factor in
reproductive failure for a maternal colony of Townsend's big-eared bat
(Corynorhinus townsendii) in California (Fellers 2000, pp. 524-525).
Many of the roosting sites used by the Pacific sheath-tailed bat on
Aguiguan appear to be impassable to rats; however, this may be due to
rats limiting the selection of roosting sites because of their foraging
and surveillance for prey in caves (Wiles and Worthington 2002, p. 18;
Berger et al. 2005, p. 144). Because rats occur on all of the Mariana
Islands, the Service considers rats a threat to the Pacific sheath-
tailed bat.
Rat Predation on Skinks--Rats are known to prey on a variety of
skink species around the globe (Crook 1973 in Towns et al. 2001, p. 3;
Whitaker 1973 in Towns et al. 2001, p. 3; McCallum 1986 in Towns et al.
2001, p. 3; Towns et al. 2001, pp. 3-4, 6-8; Towns et al. 2006, pp.
875-877, 883). A New Zealand study showed the cause of the decline of
rare reptiles on island reserves became evident through associations
with the spread of Pacific rats (Rattus exulans) to these island
reserves (Crook, 1973; Whitaker, 1973, 1978; and McCallum, 1986 in
Towns et al. 2001, p. 3). Other restoration projects in New Zealand
have demonstrated the native reptile populations undergo a resurgence
following aggressive conservation activities to control predatory
mammals, especially rodents (Towns et al. 2001, p. 3). The reptile
species showing the most rapid response to removal of rats was the
shore skink (Oligosoma smithi), with an increase of the capture
frequency of shore skinks by up to 3,600 percent over 9 years (Towns
1994, unpub. in Towns et al. 2001, p. 10). Rats occur on all of
[[Page 59402]]
the Mariana Islands and are a threat to the Slevin's skink on the
islands on which it currently occurs (Cocos Island, Alamagan, and
Sarigan), and are a threat on islands where the skink was observed in
the 1980s and 1990s (Guguan, Pagan, and Asuncion) but for which their
current status is unkown. Once thought to be extirpated from Cocos
Island (just offshore of Guam), Slevin's skink was observed on Cocos
Island for the first time in more than 20 years following the
eradication of rats and monitor lizards (Fisher 2012 pers. comm., in
IUCN 2014, in litt.), indicating that predation by these nonnative
species has a significant negative effect on skink populations.
Brown Tree Snake (BTS)
The BTS (see ``Habitat Destruction and Modification by Introduced
Small Vertebrates,'' above) preys upon a wide variety of animals, and
although it is only known to occur on Guam at this time, it is an
enormous concern that the BTS will be introduced to other Mariana
Islands (The Brown Tree Snake Control Committee 1996, pp. 1, 5). This
nocturnal arboreal snake occupies all ecosystems on Guam, and consumes
small mammals and lizards, usually in their neonatal state (Rodda and
Savidge 2007, pp. 307, 314). The BTS is attributed with the
extirpation, or contribution thereof, of 13 of Guam's 22 native bird
species. Roosting and nesting birds, eggs, and nestlings are all
vulnerable. If the BTS establishes on any other of the Mariana Islands
it will impose a wide range of negative impacts, both environmental and
economic (Campbell 2014, pers. comm.).
BTS Predation on Bats--The BTS has the potential to prey on fruit
bats and the Pacific sheath-tailed bat, as BTS are known to climb in
caves and prey on Mariana swiflets. Predation by tree snakes possibly
caused losses of sheath-tailed bats in southern Guam in the 1950s and
1960s, but invaded northern Guam too late to have played a role in the
bat's extirpation there (Wiles et al. 2011, p. 306). If the BTS should
be introduced to Aguiguan, the only island in the Mariana archipelago
that currently supports a population of the Pacific sheath-tailed bat,
it would negatively affect this population, either by predation or by
limiting available cave sites (Rodda and Savidge 2007, p. 307).
Additionally, if the BTS is introduced to islands in the Mariana
archipelago that historically supported the Pacific sheath-tailed bat
(i.e., Guam, Rota, Saipan, Tinian, Anatahan, and Maug), recovery for
this species will be difficult, and the Service considers the BTS a
potential threat to the Pacific sheath-tailed bat on these islands.
BTS Predation on Skinks--The BTS is known to prey on a wide variety
of small vertebrates on Guam, including skinks. Juvenile BTS are known
to feed exclusively on lizards (including skinks) (Savidge 1988, in
Rodda and Savidge 2007, pp. 314-315). In one study, 250 food items were
taken from the digestive systems of BTS, and of these, 194 were lizards
or lizard eggs (Savidge 1988 cited in Rodda and Fritts 1992, p. 166).
If the BTS is introduced to any of the islands that currently (Cocos
Island, Alamagan, and Sarigan) or historically (Guam, Rota, Tinian,
Aguiguan, Guguan, and Pagan) support the Slevin's skink, it will
negatively impact by decreasing populations and the numbers of
individuals, and when combined with habitat loss, and other threats,
could lead to their extirpation. Additionally, if the BTS is introduced
to islands where the Slevin's skink occurred historically (Guam, Rota,
Tinian, Aguiguan, Guguan, and Pagan), recovery for this species will be
difficult, and the Service considers the BTS a potential threat to the
Slevin's skink on these islands.
Monitor Lizard
Monitor Lizard Predation on Bats--The monitor lizard (hilitai,
Varanus indicus), a carnivorous, terrestrial, arboreal lizard that can
grow up to 3 ft (1 m) in length, is present on every island in the
Mariana Islands except for Farallon de Medinilla, Guguan, Asuncion,
Maug, and Uracas (Vogt and Williams 2004, pp. 76-77). It is unknown
when the monitor lizard was introduced to Guam and the Northern Mariana
Islands; however, it is known that the presence of this species in the
islands predates European contact (Vogt and Williams, p. 77). Monitor
lizards typically hunt over large areas and feed frequently on a wide
variety of prey including, but not limited to, crabs, snails, snakes,
lizards, skinks, fish, rats, squirrels, rabbits, sea turtle eggs, and
birds (Losos and Greene 1988, pp. 379, 393; Bennet 1995 in ISSG-GISD
2007, in litt.). In the Mariana Islands, monitor lizards prey on both
invertebrates and vertebrates, including large animals like chickens
and the endangered Micronesian megapode (Martin et al. 2008 in IUCN
2007, in litt.). Considering their varied diet, which includes small
vertebrates, and given the opportunity, predation by monitor lizards is
a threat to the Pacific sheath-tailed bat proposed for listing as an
endangered species in this rule, in the forest and cave ecosystems
(USDA-Natural Resources Conservation Service 2009, p. 8).
Monitor Lizard Predation on Skinks--Monitor lizards are known to
prey on all life stages of lizards (eggs, juveniles, and adults) and
also other monitor lizards. Therefore, we expect monitor lizards
negatively impact the Slevin's skink, also (Rodda and Fritts 1992, pp.
166-174; Vogt 2010, in litt.). The specific reasons for the decline of
Slevin's skink (currently known from only 3 of the 10 islands where
occurrences have been noted) are not known. Rodda et al. (1991) suggest
that the combination of introduced species such as rats and shrews and
other reptiles negatively impact native reptile populations, including
Slevin's skink, by aggressively competing for habitat and food
resources, and through predation (see ``Rat Predation on Skinks,''
above) (Rodda et al. 1991 in Berger et al. 2005, pp. 174-175). The
monitor lizard is known to have a varied diet (coconut crabs, snails,
snakes, lizards, skinks, fish, rats, squirrels, rabbits, sea turtle
eggs, and birds.) (Berger et al. 2005, pp. 69-70, 90, 347-348; Losos
and Greene 1988, pp. 379, 393; Bennet 1995 in ISSG-GISD 2007, in
litt.); therefore, predation of Slevin's skink by monitor lizards is a
threat to the Slevin's skink throughout its range in the Mariana
Islands.
Nonnative Fish Predation on Damselflies
A survey of the Okgok River (or Okgok Stream, also known as Babao),
conducted in 1996, showed that only four fish species (all native
species) were present: the eel Anguila marmorata, the mountain gobies
Stiphodon elegans and Sicyopus leprurus, and the flagtail or mountain
bass, Kuhlia rupestris. Other freshwater species observed included a
prawn, shrimps, and gastropods (Camacho et al. 1997, pp. 8-9).
Densities of these native fish were low, especially in areas above the
waterfall. Gobies can maneuver in areas of rapidly flowing water by
using ventral fins that are modified to form a sucking disk (Ego 1956,
in litt.). Freshwater gobies in Hawaii are primarily browsers and
bottom feeders, often eating algae off rocks and boulders, with midges
and worms being their primary food items (Ego 1956, in litt.; Kido et
al. 1993, p. 47). The flagtails were only abundant in the lower reach
of the stream. Researchers speculate that the Rota blue damselfly may
have adapted its behavior to avoid the benthic feeding habits of native
fish species.
Nonnative fish (Gambusia spp.) were introduced to Guam streams for
mosquito control. Other nonnative fish from the aquarium trade (e.g.,
guppies,
[[Page 59403]]
swordtails, mollies, betta, oscars, and koi) have been released and
documented in Guam streams. Currently, none of these fish are known
from the Okgok River (Okgok Stream, Babao) on Rota, but biologists
believe that Gambusia and guppies would be the most likely species to
be introduced (Tibbatts 2014, in litt.). The release of aquarium fish
into streams and rivers of Guam is well documented, but currently, no
nonnative fish have been found in the Rota stream (Tibbatts 2014, in
litt.). Therefore, release of nonnative fish is only a potential threat
at this time, as they could impact the Rota blue damselfly by eating
the naiad life stage, interrupting its life-cycle, and leading to its
extirpation.
Nonnnative Invertebrates
Slug Herbivory on Native Plants--The nonnative Cuban slug
(Veronicella cubensis) is considered one of the greatest threats to
native plant species on Pacific Islands (Robinson and Hollingsworth
2006, p. 2). The Cuban slug is a recent introduction to the Micronesian
islands. These terrestrial mollusks are generalist feeders, can attack
a wide variety of plants, and switch food preferences if potential food
plants change (Robinson and Hollingsworth 2006, p. 2). Slugs feed on
the two host plants (Elatostema calcareum and Procris pendunculata)
that support the Mariana eight-spot butterfly, proposed for listing as
endangered. The Cuban slug has been known on Rota since 1996, occurs in
large numbers, and is currently a pest to agricultural and ornamental
crops on the island (Badilles et al. 2010, pp. 2, 4, 8). Some
agricultural losses are reported to be as high as 70 percent of the
crop (Badilles et al. 2010, p. 7). In addition, these slugs are known
to attack orchids, which place all four species of orchids addressed in
this proposed rule (Bulbophyllum guamense, Dendrobium guamense,
Nervilia jacksoniae, and Tuberolabium guamense) at risk from slug
predation on the islands of Guam and Rota (Badilles et al. 2010, p. 7;
Cook 2012, in litt.).
Flatworm Predation on Tree Snails--The extinction of native land
snails on several Pacific Islands has been attributed to the
terrestrial Manokwari flatworm (Platydemus manokwari), native to
western New Guinea (Sugiura 2010, p. 1,499). It is believed to occur on
most of the southern Mariana Islands, and was first observed on Guam in
1978 (Hopper and Smith 1992, pp. 78, 82-83; Berger et al. 2005, p.
158). It was found to be effective in reducing the abundance of the
nonnative African snail (Achatinella fulica) by as much as 95 percent
(Hopper and Smith 1992, p. 82). This flatworm has also diminished two
nonnative predatory snails, the rosy wolf snail (Euglandina rosea) and
Gonaxis spp., both of which were previously considered a threat to the
Mariana Islands tree snails (Kerr 2013, p. 5). The Manokwari flatworm,
mostly ground-dwelling, has been observed to climb trees and feed on
juvenile Partulid snails (Hopper and Smith 1992, p. 82). Due to its
widespread occurrence on the southern Mariana Islands, and the risk of
unintentional introduction on the southern Mariana Islands, predation
by the Manokwari flatworm is considered a threat to all four tree snail
species (the Guam tree snail, the humped tree snail, Langford's tree
snail, and the fragile tree snail) proposed for listing as endangered
species.
Scale Herbivory on Cycas--Cycas micronesica is currently declining
on two (Guam and Rota) of the five Micronesian islands on which it
occurs due to the presence of a phytophagous (plant-eating) insect, the
cycad aulacaspis scale (Aulacaspis yasumatsui) (Marler and Lawrence
2012, pp. 238-240; Marler 2012, pers. comm.). The cycad aulacaspis
scale, first described in Thailand (Takagi 1977 in Marler and Lawrence
2012, p. 233), was unintentionally introduced into the United States
(Florida) a little over 20 years ago (Howard et al. 1999 in Marler and
Lawrence 2012, p. 233), from where it spread to other regions. It was
introduced to Guam in 2003, possibly via importation of the landscape
cycad, Cycas revoluta (Marler and Lawrence 2012, p. 233). By 2005, the
cycad aulacaspis scale had spread throughout the forests of Guam.
Although this scale has infested C. micronesica populations on Guam,
Rota, and the larger islands of Palau, most of the data has been
collected on Guam, where more than 50 percent of the total known Cycas
individuals occur (Marler 2012, pers. comm.). In 2002, prior to the
scale infestation, C. micronesica was the most abundant tree species on
Guam (Donnegan et al. 2002, p. 16). At an international meeting of the
Cycad Specialist Group in Mexico in 2005, the cycad aulacaspis scale
was identified as a critical issue for cycad conservation worldwide and
was given priority status (IUCN/Species Survival Commission Cycad
Specialist Group 2014, in litt.).
The cycad aulacaspis scale attacks every part of the leaf, which
subsequently turns white. The leaf then collapses, and with progressive
infestation, death of the entire plant can occur in less than 1 year
(Marler and Muniappan 2006, pp. 3-4). Field studies conducted on the
Ritidian National Wildlife Refuge on Guam by Marler and Lawrence (2012,
p. 233) between 2004 and 2011 found that 6 years after the cycad
aulacaspis scale was found on the refuge, mortality of C. micronesica
there had reached 92 percent. The scale first killed all seedlings at
their study site, followed by the juveniles, then most of the adult
plants. The cycad aulacaspis scale is unusual in that it also infests
the roots of its host plant at depths of up to 24 in (60 cm) in the
soil (University of Florida 2014, in litt.). Marler and Lawrence (2012,
pp. 238, 240) predict that if the predation by cycad aulacaspis scale
is unabated, it will cause the extirpation of C. micronesica from
western Guam by 2019.
Nonnative specialist arthropods like the cycad aulacaspis scale are
particularly harmful to native plants when introduced to small insular
oceanic islands because the native plants lack the shared evolutionary
history with arthropods and have not developed resistance mechanisms
(Elton 1958 in Marler and Lawrence 2012, p. 233), and the nonnative
arthropods are not constrained by the natural pressures or predators of
their native range (Howard et al. 1999, p. 26; Keane and Crawely 2002
in Marler and Lawrence 2012, p. 233). In addition, C. micronesica is
the sole native host of the cycad aulacaspis scale on Guam, which
raises concerns to biologists who predict that the extirpation of C.
micronesica from Guam will bring about negative cascading ecosystem
responses and manifold ecological changes (Marler and Lawrence 2012, p.
233). Because this scale spread to Rota in 2006 (Moore et al. 2006, in
litt.), and the larger islands of Palau in 2008 (Marler in Science
Daily 2012, in litt.), the same degree of negative impact to C.
micronesica in these areas is likely to occur. As shown in other case
studies worldwide, the scale insects are known to spread rapidly,
within a few months, from the site of introduction (University of
Florida 2014, in litt.).
Although the scale is present on the larger islands of Palau, it
has not yet reached the numerous smaller Rock Islands, where more than
1,000 individuals of C. micronesica are estimated to occur. As scales
can be wind dispersed, it could be a short amount time for infestation
in the Rock Islands, as shown by its rapid spread throughout Florida
between 1996 and 1998 (Marler 2014, in litt.; University of Florida
2014, in litt). The Rock Islands are a popular tourist destination, and
the scale could also be inadvertently transported on plant material and
soils (International Coral Reef Action Network 2014, in litt.). Yap is
an
[[Page 59404]]
intermediate stop-over point for those traveling between Guam and
Palau. Cycas micronesica on Yap are also considered at risk as scales
can be spread by wind dispersal and on transportation of already
infested plant material and soil; and because of the rapidity with
which it spreads (ISSG-GISD 2014, in litt.; University of Florida 2014,
in litt.). In addition, three other insects (a nonnative butterfly
(Chilades pandava), a nonnative leaf miner (Erechthias sp.), and a
native stem borer (Dihammus marianarum), opportunistically feed on C.
micronesica weakened by the cycad aulacaspis scale, compounding its
negative impacts (Marler 2013, pp. 1,334-1,336).
Scales, once established, require persistent control efforts
(University of Florida 2014, in litt.; Gill 2012, in litt). Within the
native range of the scale in southeast Asia, cycads are not affected,
as the scale is kept in check by native predators; however, there are
no predators of the scale in areas where it is newly introduced (Howard
et al. 1999, p. 15). Release of biocontrols has been attempted to abate
the scale infestation; however, these were unsuccessful: Rhyzobius
lophanthae in 2004, which established immediately; Coccobius fulvus in
2005, which did not establish; and Aphytis lignanensis in 2012, which
died in the laboratory prior to release (Moore et al. 2006, in litt.).
Rhyzobius lophanthae prolonged the survival of many Cycas trees during
the first 6 years of scale infestation; however, with time, the size
difference between the scale and R. lophanthae proved to be a problem
when it was observed that the scale could find locations on the Cycas
plant body that the predator (R. lophanthae) could not access (Marler
and Moore 2010, p. 838). Even with this biocontrol, Cycas micronesica
populations are still declining and no reproduction has been observed
on Guam since 2005 (Moore et al. 2006, in litt.).
Ant Predation on Butterflies--Four species of nonnative ants have
been observed to prey upon the Mariana eight-spot butterfly (Schreiner
and Nafus 1996, p. 3) and are believed to also negatively impact the
Mariana wandering butterfly, the two butterfly species proposed for
listing as endangered species in this rule: (1) dwarf pedicel ants
(Tapinoma minutum); (2) tropical fire ants (Solenopsis geminata); (3)
white-footed ants (Technomyrmex albipes); and (4) bi-colored trailing
ants (Monomorium floricola). These ants parasitize the butterfly eggs
(Schreiner and Nafus 1996, p. 3). Many ant species are known to prey on
all immature stages of Lepidoptera and can completely exterminate
populations (Zimmerman 1958). In a 1-year study, Schreiner and Nafus
(1996, pp. 3-4) found predation by nonnative ants to be one of the
primary causes of mortality (over 90 percent) in the Mariana eight-spot
butterfly. These four ant species occur on the islands of Guam, Rota,
and Saipan, which support the two butterfly species. Biologists
observed high mortality of the instar larval stages of the Mariana
eight-spot butterfly (Schreiner and Nafus 1996, pp. 2-4), for unknown
reasons, but this, compounded with predation of eggs by ants,
negatively impacts both the Mariana eight-spot butterfly and the
Mariana wandering butterfly.
Parasitic Wasp Predation on Butterflies--Two native parasitoid
wasps, Telenomus sp. (no common name) and Ooencyrtus sp. (no common
name), are known to lay their eggs in eggs of native Mariana Islands
Lepidoptera species (Mariana eight-spot butterfly (Guam and Saipan) and
Mariana wandering butterfly (Guam and Rota) (Schreiner and Nafus 1996,
pp. 2-5). These wasps are tiny and likely hitch-hiked with adult female
butterflies in order to access freshly laid eggs, as has been observed
in related species (Woelke 2008). These wasps negatively impact the
Mariana eight-spot and Mariana wandering butterflies because they lay
their own eggs within the butterfly eggs, thus preventing caterpillar
development. Habitat destruction and loss of host plants, along with
continued parasitism, act together to negatively affect populations and
individuals of the Mariana eight-spot butterfly and the Mariana
wandering butterfly. These parasitoid wasps occur on the three islands
(Guam, Rota, and Saipan) that support the Mariana eight-spot butterfly
and the Mariana wandering butterfly proposed for listing as endangered
species.
Conservation Efforts To Reduce Disease or Predation
Conservation efforts to reduce predation mirror those mentioned
under Factor A. Habitat Destruction, Modification, or Curtailment of
Its Range (see ``Conservation Efforts To Reduce Habitat Destruction,
Modification, or Curtailment of Its Range,'' above).
Summary of Disease and Predation
We are unaware of any information that indicates that disease is a
threat to any of the 23 species in this proposed rule.
Although conservation measures are in place in some areas where one
or more of the 23 Mariana Islands species occurs, information does not
indicate that they are ameliorating the threat of predation described
above. Therefore, we consider predation by nonnative animal species
(pigs, deer, rats, brown tree snakes, monitor lizards, slugs, ants, and
wasps) to pose an ongoing threat to 17 of 23 species addressed in this
proposed rule (see Table 3, above) throughout their ranges for the
following reasons:
(1) Observations and reports have documented that pigs and deer
browse and trample 5 of the 23 plant species (Cycas micronesica,
Eugenia bryanii, Heritiera longipetiolata, Psychotria malaspinae, and
Solanum guamense), and the host plants of the Mariana eight-spot
butterfly, addressed in this rule (see Table 3), in addition to studies
demonstrating the negative impacts of ungulate browsing and trampling
on native plant species of the islands (Spatz and Mueller-Dombois 1973,
p. 874; Diong 1982, pp. 160-161; Cuddihy and Stone 1990, p. 67).
(2) Nonnative rats, snakes, and monitor lizards prey upon one or
more of the following 6 animal species addressed in this proposed rule:
the Pacific sheath-tailed bat, Slevin's skink, and the four tree
snails.
(3) Ants and wasps prey upon the eggs and larvae of the two
butterflies, the Mariana eight-spot butterfly and Mariana wandering
butterfly.
(4) Nonnative slugs cause mechanical damage to plants and
destruction of plant parts (branches, fruits, and seeds), including
orchids, and are considered a threat to 4 of the 14 plant species in
this rule (Bulbophyllum guamense, Dendrobium guamense, Nervilia
jacksoniae, and Tuberolabium guamense).
(5) Cycas micronesica is currently preyed upon by the cycad
aulacaspis scale on three of the five Micronesian islands (Guam, Rota,
and Palau) on which it occurs (Hill et al. 2004, pp. 274-298; Marler
and Lawrence 2012, p. 233; Marler 2012, pers. comm.). This scale has
the ability to severely impact or even extirpate C. micronesica
throughout its range if not abated.
These threats are serious and ongoing, act in concert with other
threats to the species and their habitats, and are expected to continue
or increase in magnitude and intensity into the future without
effective management actions to control or eradicate them.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
The Mariana Islands encompass two different political entities, the
U.S. Territory of Guam and the U.S.
[[Page 59405]]
Commonwealth of the Northern Mariana Islands, and issues regarding
existing regulatory measures for each entity are discussed in separate
paragraphs below.
U.S. Territory of Guam
We are aware of regulatory measures regarding conservation of
natural resources established by the Government of Guam (GovGuam).
Under Guam Annotated Rules (GAR) Title 9--Animal Regulations (9 GAR--
Animal Regulations), there are two divisions: (1) Division 1: Care and
Conservation of Animals, and (2) Division 2: Conservation, Hunting and
Fishing Regulations (www.guamcourts.com, accessed 9 Feb 2014). Division
1 addresses the importation of animals, animal and zoonotic disease
control, commercial quarantine regulations, and plant and non-domestic
animal quarantine; however, there is no documentation as to what extent
this regulation is enforced. Division 2 Chapter 63 covers fish, game,
forestry, and conservation. Article 2 (sections 63201 through 63208)
describe authorities under the Endangered Species Act of Guam (Act).
This Article vests regulatory power in the Guam Department of
Agriculture. The Act prohibits, with respect to any threatened or
endangered species of plants or wildlife of Guam and the United States:
(1) Import or export of any such species to or from Guam and its
territory; (2) take of any such species within Guam and its territory;
(3) possession, processing, selling or offering for sale, delivery,
carrying, transport, or shipping, by any means whatsoever, any such
species; provided that any person who has in his possession such plants
or wildlife at the time this provision is enacted into law may retain,
process, or otherwise dispose of those plants or wildlife already in
his possession, and (4) violation of any regulation or rule pertaining
to the conservation, protections, enhancement, or management of any
designated threatened or endangered species.
As of 2009 (the currently posted list), Guam DAWR recognizes 6 of
the 23 species as endangered (the plant Heritiera longipetiolata; 3 of
the 4 tree snails (the Guam tree snail, the humped tree snail, and the
fragile tree snail), the Pacific sheath-tailed bat, and Slevin's
skink). The other 17 species on Guam proposed here for listing are not
currently recognized under the Endangered Species Act of Guam, but will
be recognized as requiring protection by the Act upon their listing as
endangered or threatened. However, this Act does not address the
threats imposed upon the 21 species that occur currently or
historically on Guam that are ongoing and are expected to increase in
magnitude in the near future (Langford's tree snail and the Rota blue
damselfly are the only species addressed in this rule with no record of
occurrence on Guam). Only three species addressed in this proposed rule
currently benefit from conservation actions on Guam, those conducted by
the Guam PEPP for Heritiera longipetiolata, Maesa walkeri, and
Psychotria malaspinae, as discussed in ``Conservation Efforts To Reduce
Habitat Destruction, Modification, or Curtailment of Its Range,''
above. Under Guam's ESA, the Department of Agriculture is authorized to
establish priorities for the conservation and protection of threatened
and endangered species and their associated ecosystems, but we are
unaware of any documentation of these priorities or actions conducted
for protection of the 21 Guam species.
U.S. Commonwealth of the Northern Mariana Islands (CNMI)
The CNMI has multiple regulatory measures in place intended to
protect natural resources (www.cnmilaw.org, accessed 9 Feb 2014 (CNMI
2014, in litt.)). Six Chapters under Title 85: Department of Land and
Natural Resources, encompass the most relevant regulatory measures with
respect to the 16 CNMI species addressed in this proposed rule
(www.cnmilaw.org, accessed 9 Feb 2014). Chapter 85-20 addresses animal
quarantine rules and regulations, including domestic animals of all
types, and associated port of entry laws. Chapter 95-30 addresses
noncommercial fish and wildlife regulations, including the List of
Protected Wildlife and Plant Species in the CNMI, which includes 1 of
the 23 species addressed in this proposed rule (the plant
Tabernaemontana rotensis). Chapter 95-30 also covers CNMI conservation
areas. Chapter 85-60 covers the Division of Plant Industry, including
plant quarantine regulations. Chapter 85-80 covers the Division of
Zoning. Chapter 85-90 addresses permits necessary for the clearing and
burning of vegetation, and removal of plants or plant products, or
soil, from areas designated as diverse forests on public lands. Chapter
85-100 addresses BTS prevention regulations.
All six Chapters under Title 85 mentioned above have a component
that is designed to protect native species, including rare species at
risk from competition and predation by nonnative, and in some cases
native, species. However, these regulations are modestly enforced and
are currently inadequate to protect the 16 CNMI species in this
proposed rule. Nonnative animals and plants have spread throughout the
island chain despite these laws being in place. Greater enforcement of
local laws in place may provide additional benefit to the 16 species
proposed for listing as endangered or threatened species in this rule
that occur in the CNMI (the plants Bulbophyllum guamense, Cycas
micronesica, Dendrobium guamense, Heritiera longipetiolata, Maesa
walkeri, Nervilia jacksoniae, Tabernaemontana rotensis, and
Tuberolabium guamense; the humped tree snail, Langford's tree snail,
and the fragile tree snail; the two butterflies, the Pacific sheath-
tailed bat, Slevin's skink, and the Rota blue damselfly).
U.S. Department of Defense (DOD)
The Sikes Act (16 U.S.C. 670) authorizes the Secretary of Defense
to develop cooperative plans with the Secretaries of Agriculture and
the Interior for natural resources on public lands. The Sikes Act
Improvement Act of 1997 requires DOD installations to prepare
Integrated Natural Resource Management Plans (INRMPs) that provide for
the conservation and rehabilitation of natural resources on military
lands consistent with the use of military installations to ensure the
readiness of the Armed Forces.
In June 2013, the Department of the Navy, Joint Region Marianas
(JRM), completed an INRMP to address the conservation, protection, and
management of fish and wildlife resources on DOD-managed and -
controlled areas on Guam, specifically Naval Base Guam and Andersen Air
Force Base, including leased lands in the CNMI on Tinian and Farallon
de Medinilla. On July 2, 2013, the Navy requested the Service's
endorsement of the JRM INRMP. To determine if an INRMP provides a
conservation benefit to listed species, the Service must consider: (1)
The extent of area and features present; (2) the type and frequency of
use of the area by the species; (3) the relevant elements of the INRMP
in terms of management objectives, activities covered, and best
management practices, and the certainty that the relevant elements will
be implemented; and (4) the degree to which the relevant elements of
the INRMP will protect the habitat from the types of effects that would
be addressed through a destruction-or-adverse-modification analysis.
The JRM INRMP is under review by the Service, but at present the Navy
is operating under an INRMP that has not yet been approved
[[Page 59406]]
by the Service as providing a conservation benefit to the species
considered for listing here that are associated with DOD lands or
activities.
Summary of the Inadequacy of Existing Regulatory Mechanisms
Both the U.S. Territory of Guam and the U.S. Commonwealth of the
Northern Mariana Islands have regulations in place designed to provide
protection for their respective natural resources, including native
forests, water resources, and the 23 species addressed in this rule;
however, enforcement of these regulations is not documented. DOD is
partnering with other agencies to prevent inadvertent transport of
deleterious species (the brown tree snake) into Guam and the Mariana
Islands, and from Guam to other areas; however, the current
conservation actions proposed in the 2013 INRMP have not been
determined to provide a benefit to the Mariana Islands species
considered here, and threats imposed upon the 23 species persist and
are expected to increase in magnitude (see Table 3). Examples include
continued development and habitat modification, spread and introduction
of nonnative plants and animals throughout the islands, fires started
by hunters, sales of tree snail shells, and predation and herbivory by
nonnative animals.
The capacity of the U.S. Territory of Guam and the U.S.
Commonwealth of the Northern Mariana Islands and other Federal and
State agencies in the Mariana Islands to mitigate the effects of
introduced pests, such as ungulates and weeds, is limited due to the
large number of taxa currently causing damage. Resources available to
reduce the spread of these species and counter their negative
ecological effects are limited. Despite the fact that both GovGuam and
the CNMI receive assistance from the USDA, U.S. Department of Homeland
Security, and other Federal agencies, the scope of threats remains
challenging.
Factor E. Other Natural or Manmade Factors Affecting Their Continued
Existence
Other factors that pose threats to some or all of the 23 species
include ordnance and live-fire training, water extraction, recreational
off-road vehicles, and small numbers of populations and small
population sizes. Each threat is discussed in detail below, along with
identification of which species are affected by these threats.
Ordnance and Live-Fire Training
Several individuals of the plants Cycas micronesica and Heritiera
longipetiolata, proposed for listing as threatened and endangered
species (respectively) in this rule, are located on the Tarague
ridgeline near a firing range on Andersen AFB. There is a buffer zone
at the end of the range, but not to either side. Ricochet bullets and
ordnance have broken branches and made holes through parts of these
trees, causing added stress and a possible avenue for disease (Guam
DAWR 2013, pers. comm.). Military training is expected to be conducted
within 5 Live-Fire Training Ranges (incorporating a Multi-Purpose
Machine Gun Range), for 39 weeks out of the year, with 2 night-
trainings per week (NavFac Engineering Command Pacific 2014, pp. ES-1,
ES-5). Depending on the type of ammunition used, there could be
substantial damage to vegetation, or a possible fire started from
ordnance use, which could destroy individuals of Cycas micronesica and
Heritiera longipetiolata and their habitat.
Water Extraction
The Rota blue damselfly was only first discovered in April 1996,
outside the Talakhaya Water Cave (also known as Sonson Water Cave)
located below the Sabana plateau on the island of Rota (see the
species' description, above) (Polhemus et al. 2000, pp. 1-8; Camacho et
al. 1997, p. 4). The Talakhaya Water Cave, As Onon Spring, and the
perennial stream formed from runoff from the springs at the Water Cave
support the only known population of the Rota blue damselfly. Rota's
municipal water is obtained by gravity flow from these two springs (up
to 1.8 Mgal/day) (Keel et al. 2007, pp. 1, 5; Stafford et al. 2002, p.
17). Under ordinary climatic conditions, this area supplies water in
excess of demand but ENSO-induced drought conditions can lead to
significantly reduced discharge, or may completely dewater the streams
(Keel et al. 2007, pp. 3, 6, 19). In 1998, water captured from the
springs was inadequate for municipal use, and water rationing was
instituted (Keel et al. 2007, p. 6).
As the annual temperature rises resulting from global climate
change, other weather regime changes such as increases in droughts,
floods, and typhoons will occur (Giambelluca et al. 1991, p. iii).
Increasing night temperatures cause a change in mean precipitation,
with increased occurrences of drought cycles (Loope and Giambelluca
1998, pp. 514-515; Emanuel et al. 2008, p. 365; U.S. Global Change
Research Program (US-GCRP) 2009, pp. 145-149, 153; Keener et al. 2010,
pp. 25-28; Finucane et al. 2012, pp. 23-26; Keener et al. 2012, pp. 47-
51). The limestone substrate of Rota is porous, with filtration through
central Sabana being the sole water source for the few streams on the
island and for human use. There are no other ground water supplies on
the island, and storage capacity is limited. The Rota blue damselfly is
dependent upon any water that escapes the Talakhaya Springs naturally,
what is not already removed for human use. The likelihood of dewatering
of the Talakhaya Springs is high due to climate change causing
increased ENSO conditions, and increased human demand. The ``Public and
Agency Participation'' section of the Comprehensive Wildlife
Conservation Strategy for the Commonwealth of the Northern Mariana
Islands (2005, p. 347) cites ``individuals state that the Department of
Public Works has been increasing their water extraction from Rota's
spring/stream systems. Historically, this water source flowed year-
around, yet now they are essentially dry most of each year'' (see the
species description ``Rota blue damselfly,'' and ``Stream Ecosystem,''
above, for further discussion). Water extraction is an ongoing threat
to the Rota blue damselfly. The loss of this perennial stream would
remove the only known breeding and foraging habitat of the sole known
population of the Rota blue damselfly, likely leading to its
extinction.
Recreational Vehicles
The savanna areas of Guam are popular for use of recreational
vehicles. Damage and destruction caused by these vehicles are a direct
threat to the plants Hedyotis megalantha and Phyllanthus saffordii,
proposed for listing as endangered species in this rule, as well as a
threat to the savanna habitat that supports these plant species
(Guiterrez 2013, in litt.; Guam DAWR 2013, pers. comm.). Hedyotis
megalantha and P. saffordii are particularly at risk, as the only known
individuals of these species are scattered on the savanna.
Small Numbers of Individuals and Populations
Species that are endemic to single islands are inherently more
vulnerable to extinction than are widespread species, because of the
increased risk of genetic bottlenecks, random demographic fluctuations,
climate change effects, and localized catastrophes, such as typhoons
and disease outbreaks (Pimm et al. 1988, p. 757; Mangel and Tier 1994,
p. 607). These problems are further magnified when populations are few
and restricted to a very small geographic area, and when the number of
individuals in each
[[Page 59407]]
population is very small. Species with these population characteristics
face an increased likelihood of extinction due to changes in
demography, the environment, genetic bottlenecks, or other factors
(Gilpin and Soul[eacute] 1986, pp. 24-34). Small, isolated populations
often exhibit reduced levels of genetic variability, which diminishes
the species' capacity to adapt and respond to environmental changes,
thereby lessening the probability of long-term persistence (Barrett and
Kohn 1991, p. 4; Newman and Pilson 1997, p. 361). Very small, isolated
populations are also more susceptible to reduced reproductive vigor due
to ineffective pollination (plants), inbreeding depression (plants and
animals), and hybridization (plants and insects). The problems
associated with small population size and vulnerability to random
demographic fluctuations or natural catastrophes are further magnified
by synergistic interactions with other threats, such as those discussed
above (see Factor A. The Present or Threatened Destruction,
Modification, or Curtailment of Its Habitat or Range and Factor C.
Disease or Predation, above).
Plants--In the 1990s, individuals of Tabernaemontana rotensis were
vandalized and set on fire (Mehrhoff 2014, in litt.). Because this
species is limited in its range, and is vulnerable to any vandalism, we
consider vandalism to be a significant threat throughout its range.
The following 5 plant species have a very limited number of
individuals (fewer than 50) in the wild: Maesa walkeri, Psychotria
malaspinae, Solanum guamense, Tinospora homosepala, and Tuberolabium
guamense. We consider these species highly vulnerable to extinction due
to threats associated with small population size or small number of
populations because:
The only known occurrences of Maesa walkeri, Psychotria
malaspinae, Solanum guamense, Tinospora homosepala, and Tuberolabium
guamense are threatened either by ungulates, nonnative plants, fire, or
a combination of these.
Psychotria malaspinae, Solanum guamense, and Tuberolabium
guamense are all known from fewer than 10 scattered individuals
(Yoshioka 2008, p. 15; Cook 2012, in litt.; CPH 2012f--Online Herbarium
Database; Harrington et al. 2012, in litt.; Grimm 2013, in litt.;
Rogers 2012, in litt.; WCSP 2012d--Online Herbarium Database).
Animals--Like most native island biota, the single island endemics
Guam tree snail, Langford's tree snail, and Rota blue damselfly are
particularly sensitive to disturbances due to low number of
individuals, low population numbers, and small geographic ranges. We
consider these three species vulnerable to extinction due to the low
number of individuals and low number of populations because these
species occur on single islands, are declining in number of individuals
and range, and are at risk of one or more of the following: predation
by nonnative rats, monitor lizards, and flatworms; habitat degradation
and destruction by nonnative ungulates; fire; drought; and water
extraction (see Factor A. The Present or Threatened Destruction,
Modification, or Curtailment of Its Habitat or Range and Factor C.
Disease or Predation, above).
Conservation Efforts To Reduce Other Natural or Manmade Factors
Affecting Its Continued Existence
We are unaware of any conservation actions planned or implemented
at this time to abate the threats to the species negatively impacted by
water extraction (Rota blue damselfly), recreational vehicles (Hedyotis
megalantha and Phyllanthus saffordii), or low numbers (the plants Maesa
walkeri, Psychotria malaspinae, Solanum guamense, Tinospora homosepala,
and Tuberolabium guamense; the Guam tree snail and Langford's tree
snail; and the Rota blue damselfly).
Summary of Other Natural or Manmade Factors Affecting Their Continued
Existence
We consider the threat from limited numbers of populations and low
numbers of individuals (fewer than 50) to be serious and ongoing for 5
plant species addressed in this proposed rule (Maesa walkeri,
Psychotria malaspinae, Solanum guamense, Tinospora homosepala, and
Tuberolabium guamense) because: (1) These species may experience
reduced reproductive vigor due to ineffective pollination or inbreeding
depression; (2) they may experience reduced levels of genetic
variability, leading to diminished capacity to adapt and respond to
environmental changes, thereby lessening the probability of long-term
persistence; and (3) a single catastrophic event (e.g., fire) may
result in extirpation of remaining populations and extinction of the
species. This threat applies to the entire range of each species.
The threat to the Guam tree snail, Langford's tree snail and Rota
blue damselfly from limited numbers of individuals and populations is
ongoing and is expected to continue into the future because population
numbers of these species are so low that: (1) They may experience
reduced reproductive vigor due to inbreeding depression; (2) they may
experience reduced levels of genetic variability leading to diminished
capacity to adapt and respond to environmental changes, thereby
lessening the probability of long-term persistence; (3) a single
catastrophic event (e.g., super typhoon) may result in extirpation of
remaining populations and extinction of these species; and (4) species
with few known locations are less resilient to threats that might
otherwise have a relatively minor impact on widely distributed species.
For example, an increase in predation of these species that might be
absorbed in a widely distributed species could result in a significant
decrease in survivorship or reproduction of a species with limited
distribution. Additionally, the limited distribution of these species
thus magnifies the severity of the impact of the other threats
discussed in this proposed rule.
Summary of Factors
The primary factors that pose serious and ongoing threats to 1 or
more of the 23 species throughout their ranges in this proposed rule
include: Habitat degradation and destruction by development, activities
associated with military training and urbanization, nonnative ungulates
and plants, rats, fire, typhoons, and climate change, and the
interaction of these threats (Factor A); overutilization of tree snails
due to collection for trade or market (Factor B); predation by
nonnative animal species (ungulates, deer, rats, brown tree snakes,
monitor lizards, slugs, flatworms, ants, and wasps) (Factor C);
inadequate regulatory mechanisms to address the spread or control of
nonnative species (Factor D); and ordnance and live-fire training,
water extraction, recreational vehicles, and limited numbers of
populations and individuals (Factor E). While we acknowledge the
voluntary conservation measures described above may help to ameliorate
1 or more of the threats to the 23 species addressed in this proposed
rule, these conservation measures are insufficient to control or
eradicate these threats to the point where listing is not warranted.
Proposed Determination
Section 4 of the Act (16 U.S.C. 1533), and its implementing
regulations at 50 CFR part 424, set forth the procedures for adding
species to the Federal Lists of Endangered and Threatened Wildlife and
Plants. Under section 4(a)(1) of the Act, we may list a species based
on (A) The present or threatened destruction,
[[Page 59408]]
modification, or curtailment of its habitat or range; (B)
Overutilization for commercial, recreational, scientific, or
educational purposes; (C) Disease or predation; (D) The inadequacy of
existing regulatory mechanisms; or (E) Other natural or manmade factors
affecting its continued existence. Listing actions may be warranted
based on any of the above threat factors, singly or in combination.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the 23 species proposed for listing as endangered or threatened
species in this rule. We find all 23 species face threats that are
ongoing and expected to continue into the future throughout their
ranges from the present destruction and modification of their habitats
from nonnative feral ungulates, rats, and nonnative plants (Factor A).
Destruction and modification of habitat by development, military
training, and urbanization is a threat to 13 of the 14 plant species
(Bulbophyllum guamense, Cycas micronesica, Dendrobium guamense, Eugenia
bryanii, Hedyotis megalantha, Heritiera longipetiolata, Maesa walkeri,
Nervilia jacksoniae, Phyllanthus saffordii, Psychotria malaspinae,
Solanum guamense, Tabernaemontana rotensis, and Tuberolabium guamense)
and to 8 of the 9 animal species (the Pacific sheath-tailed bat,
Slevin's skink, the Mariana eight-spot butterfly, the Rota blue
damselfly, the Guam tree snail, the humped tree snail, Langford's tree
snail, and the fragile tree snail). Habitat destruction and
modification from fire is a threat to nine of the plant species
(Bulbophyllum guamense, Cycas micronesica, Dendrobium guamense,
Hedyotis megalantha, Maesa walkeri, Nervilia jacksoniae, Phyllanthus
saffordii, Tabernaemontana rotensis, and Tuberolabium guamense) and two
tree snails (the Guam tree snail and the humped tree snail).
Destruction and modification of habitat from typhoons is a threat to
all 23 species. Rising temperatures and other effects of projected
climate change may impact all 23 species, but there is limited
information on the exact nature of impacts that these species may
experience (Factor A).
Overcollection for commercial and recreational purposes poses a
threat to all four tree snail species (the Guam tree snail, the humped
tree snail, Langford's tree snail, and the fragile tree snail) (Factor
B).
Predation or herbivory on 9 of the 14 plant species (Bulbophyllum
guamense, Cycas micronesica, Dendrobium guamense, Eugenia bryanii,
Heritiera longipetiolata, Nervilia jacksoniae, Psychotria malaspinae,
Solanum guamense, and Tuberolabium guamense) and 8 of the 9 animals
(all except the Rota blue damselfly) by feral pigs, deer, brown tree
snakes, rats, monitor lizards, slugs, flatworms, ants, or wasps poses a
serious and ongoing threat (Factor C).
The inadequacy of existing regulatory mechanisms (i.e., inadequate
protection of habitat and inadequate protection from the introduction
of nonnative species) poses a serious and ongoing threat to all 23
species (Factor D).
There are serious and ongoing threats to five plant species (Maesa
walkeri, Psychotria malaspinae, Solanum guamense, Tinospora homosepala,
and Tuberolabium guamense), the Guam tree snail, Langford's tree snail,
the fragile tree snail, and Rota blue damselfly due to small numbers of
populations and individuals; to Tabernaemontana rotensis due to
vandalism; to Cycas micronesica and Heritiera longipetiolata from
ordnance and live-fire training; to the Rota blue damselfly from water
extraction; and to Hedyotis megalantha and Phyllanthus saffordii from
recreational vehicles (Factor E) (see Table 3). These threats are
exacerbated by these species' inherent vulnerability to extinction from
stochastic events at any time because of their endemism, small numbers
of individuals and populations, and restricted habitats.
The Act defines an endangered species as any species that is ``in
danger of extinction throughout all or a significant portion of its
range'' and a threatened species as any species ``that is likely to
become endangered throughout all or a significant portion of its range
within the foreseeable future.'' We find that 21 of the 23 Mariana
Islands species are presently in danger of extinction throughout their
entire range, based on the severity and scope of the ongoing and
projected threats described above. These 21 species are: the 12 plants
Bulbophyllum guamense, Dendrobium guamense, Eugenia bryanii, Hedyotis
megalantha, Heritiera longipetiolata, Maesa walkeri, Nervilia
jacksoniae, Phyllanthus saffordii, Psychotria malaspinae, Solanum
guamense, Tinospora homosepala, and Tuberolabium guamense; and all 9
animals: the Pacific sheath-tailed bat (Emballonura semicaudata
rotensis), Slevin's skink (Emoia slevini), the Mariana eight-spot
butterfly (Hypolimnas octocula mariannensis), the Mariana wandering
butterfly (Vagrans egistina), the Rota blue damselfly (Ischnura luta),
the Guam tree snail (Partula radiolata), the humped tree snail (Partula
gibba), Langford's tree snail (Partula langfordi), and the fragile tree
snail (Samoana fragilis).
We conclude these 21 species are endangered due to the small number
of individuals representing the entire species and the limited or
concentrated geographic distribution of those remaining individuals or
populations, rendering the species in its entirety highly susceptible
to extinction as a consequence of these imminent threats. These threats
are exacerbated by the loss of redundancy and resiliency of these
species, and the continued inadequacy of existing protective
regulations. Therefore, on the basis of the best available scientific
and commercial information, we have determined that each of these 21
species meets the definition of an endangered species under the Act. We
find that threatened species status is not appropriate for these 21
species, as the threats are already occurring rangewide and are not
localized, and because the threats are ongoing and expected to continue
into the future. In addition, the remaining populations of these
species are so small that we cannot conclude they are likely capable of
persisting into the foreseeable future in the face of the current
threats. We, therefore, propose to list these 21 species as endangered
species in accordance with section 3(6) of the Act.
As noted above, the Act defines a threatened species as any species
``that is likely to become endangered throughout all or a significant
portion of its range within the foreseeable future.'' We propose to
list two plant species as threatened species in accordance with section
3(6) of the Act, Cycas micronesica and Tabernaemontana rotensis. Cycas
micronesica occurs on Guam, Rota, and Pagan in the CNMI, as well as on
islands in the nations of Palau and Yap. More than 50 percent of the
known individuals occur on Guam and Rota in the CNMI, and are currently
impacted by the cycad aulacaspis scale, to the extent that botanists
estimate the species could be largely extirpated from these two islands
within 5 years, by 2019. The status of the species on Pagan is unknown,
although only a small population is known from that island. While the
scale has reached the larger islands of Palau, it has not yet reached
the Rock Islands of Palau, or Yap, and these islands may afford some
temporary protection for the remaining individuals while control
methods and biocontrols for the cycad aulacaspis scale are undergoing
research. Due to the rapid spread of the scale and associated high
mortality, however, populations in Palau and Yap remain
[[Page 59409]]
highly vulnerable. Given its relatively greater population size and
distribution on multiple islands, some of which have not yet been
affected by the cycad aulacaspis scale, we conclude that Cycas
micronesica is not currently in danger of extinction, thus endangered
status is not appropriate. However, given the observed rapid spread of
the cycad aulacaspis scale, the likelihood that the scale will soon be
transported to areas that are currently unaffected, and the high
mortality rate experienced by Cycas micronesica upon exposure to the
scale, we conclude that Cycas micronesica is likely to become in danger
of extinction within the foreseeable future. Therefore, on the basis of
the best available scientific and commercial information, we propose
that this species meets the definition of a threatened species under
the Act.
Tabernaemontana rotensis was, until recently, believed to be part
of the wider ranging T. pandacaqui, until genetic studies showed it to
be unique to Guam and Rota. There may be as many as 8,000 individuals
on Guam, but only a few on Rota; however, the threats of habitat
destruction and modification, fire, typhoons, climate change, and
inadequate regulatory mechanisms have a combined impact on all
occurrences, to the extent that we believe it is likely to become in
danger of extinction within the foreseeable future throughout all of
its range. Because Tabernaemontana rotensis species still has a
relatively large number of individuals, even in the face of current
threats, we conclude the species will likely persist into the
foreseeable future. As we do not conclude that Tabernaemontana rotensis
is currently in danger of extinction, endangered status is not
appropriate. However, because the species has been reduced to only a
few individuals on Rota, and the remaining population on Guam is
subject to a suite of ongoing threats as described above, we conclude
that Tabernaemontana rotensis will become in danger of extinction
within the foreseeable future. Therefore, on the basis of the best
available scientific and commercial information, we propose that this
species meets the definition of a threatened species under the Act.
Under the Act and our implementing regulations, a species may
warrant listing if it is endangered or threatened throughout all or a
significant portion of its range. Each of the 23 Mariana Islands
species proposed for listing in this rule is highly restricted in its
range, and the threats occur throughout its range. Therefore, we
assessed the status of each species throughout its entire range. In
each case, the threats to the survival of these species occur
throughout the species' ranges and are not restricted to any particular
portion of those ranges. Accordingly, our assessment and proposed
determination applies to each species throughout its entire range, and
we do not need to further consider the status of each species in a
significant portion of their respective ranges.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness, and
conservation by Federal, State, and local agencies, private
organizations, and individuals. The Act encourages cooperation with the
States and territories and requires that recovery actions be carried
out for all listed species. The protection required by Federal agencies
and the prohibitions against certain activities are discussed, in part,
below.
The primary purpose of the Act is the conservation of endangered
and threatened species and the ecosystems upon which they depend. The
ultimate goal of such conservation efforts is the recovery of these
listed species, so that they no longer need the protective measures of
the Act. Subsection 4(f) of the Act requires the Service to develop and
implement recovery plans for the conservation of endangered and
threatened species. The recovery planning process involves the
identification of actions that are necessary to halt or reverse the
species' decline by addressing the threats to its survival and
recovery. The goal of this process is to restore listed species to a
point where they are secure, self-sustaining, and functioning
components of their ecosystems.
Recovery planning includes the development of a recovery outline
shortly after a species is listed and preparation of a draft and final
recovery plan. The recovery outline guides the immediate implementation
of urgent recovery actions and describes the process to be used to
develop a recovery plan. Revisions of the plan may be done to address
continuing or new threats to the species, as new substantive
information becomes available. The recovery plan identifies site-
specific management actions that set a trigger for review of the five
factors that control whether a species remains endangered or may be
downlisted or delisted, and methods for monitoring recovery progress.
Recovery plans also establish a framework for agencies to coordinate
their recovery efforts and provide estimates of the cost of
implementing recovery tasks. Recovery teams (composed of species
experts, Federal and State agencies, nongovernmental organizations, and
stakeholders) are often established to develop recovery plans. When
completed, the recovery outline, draft recovery plan, and the final
recovery plan will be available on our Web site (http://www.fws.gov/endangered), or from our Pacific Islands Fish and Wildlife Office (see
FOR FURTHER INFORMATION CONTACT).
Implementation of recovery actions generally requires the
participation of a broad range of partners, including other Federal
agencies, States, territories, nongovernmental organizations,
businesses, and private landowners. Examples of recovery actions
include habitat restoration (e.g., restoration of native vegetation),
research, captive propagation and reintroduction, and outreach and
education. The recovery of many listed species cannot be accomplished
solely on Federal lands because their range may occur primarily or
solely on non-Federal lands. To achieve recovery of these species
requires cooperative conservation efforts on all lands.
If these species are listed, funding for recovery actions will be
available from a variety of sources, including Federal budgets, State
programs, and cost share grants for non-Federal landowners, the
academic community, and nongovernmental organizations. In addition,
pursuant to section 6 of the Act, the State(s) of the U.S. Territory of
Guam and the U.S. Commonwealth of the Northern Mariana Islands would be
eligible for Federal funds to implement management actions that promote
the protection or recovery of the 23 species. Information on our grant
programs that are available to aid species recovery can be found at:
http://www.fws.gov/grants.
Although these species are only proposed for listing under the Act
at this time, please let us know if you are interested in participating
in recovery efforts for any of these species. Additionally, we invite
you to submit any new information on these species whenever it becomes
available and any information you may have for recovery planning
purposes (see FOR FURTHER INFORMATION CONTACT).
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as an
endangered or threatened species and with respect to its critical
habitat, if any is designated. Regulations implementing this
interagency cooperation provision of the Act are codified at 50 CFR
part
[[Page 59410]]
402. Section 7(a)(4) of the Act requires Federal agencies to confer
with the Service on any action that is likely to jeopardize the
continued existence of a species proposed for listing or result in
destruction or adverse modification of proposed critical habitat. If a
species is listed subsequently, section 7(a)(2) of the Act requires
Federal agencies to ensure that activities they authorize, fund, or
carry out are not likely to jeopardize the continued existence of the
species or destroy or adversely modify its critical habitat. If a
Federal action may affect a listed species or its critical habitat, the
responsible Federal agency must enter into consultation with the
Service.
For the 23 plants and animals proposed for listing as endangered or
threatened species in this rule, Federal agency actions that may
require consultation as described in the preceding paragraph include,
but are not limited to, actions within the jurisdiction of the Natural
Resources Conservation Service, the U.S. Army Corps of Engineers, the
U.S. Fish and Wildlife Service, and branches of the DOD. Examples of
these types of actions include activities funded or authorized under
the Farm Bill Program, Environmental Quality Incentives Program, Ground
and Surface Water Conservation Program, Clean Water Act (33 U.S.C. 1251
et seq.), Partners for Fish and Wildlife Program, and DOD activities
related to training, facilities construction and maintenance, or other
military missions.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to all endangered and
threatened wildlife and plants. The prohibitions, codified at 50 CFR
17.21 for endangered wildlife, and at 17.61 and 17.71 for endangered
and threatened plants, respectively, apply. For listed wildlife
species, these prohibitions, in part, make it illegal for any person
subject to the jurisdiction of the United States to take (includes
harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or
collect; or to attempt any of these), import, export, ship in
interstate commerce in the course of commercial activity, or sell or
offer for sale in interstate or foreign commerce any listed species.
Under the Lacey Act (18 U.S.C. 42-43; 16 U.S.C. 3371-3378), it is also
illegal to possess, sell, deliver, carry, transport, or ship any such
wildlife that has been taken illegally. Certain exceptions apply to
agents of the Service and State conservation agencies.
With respect to endangered plants, prohibitions outlined at 50 CFR
17.61 make it illegal for any person subject to the jurisdiction of the
United States to import or export, transport in interstate or foreign
commerce in the course of a commercial activity, sell or offer for sale
in interstate or foreign commerce, or to remove and reduce to
possession any such plant species from areas under Federal
jurisdiction. In addition, for endangered plants, the Act prohibits
malicious damage or destruction of any such species on any area under
Federal jurisdiction, and the removal, cutting, digging up, or damaging
or destroying of any such species on any other area in knowing
violation of any State law or regulation, or in the course of any
violation of a State criminal trespass law. Exceptions to these
prohibitions are outlined in 50 CFR 17.62.
With respect to threatened plants, 50 CFR 17.71 provides that all
of the provisions in 50 CFR 17.61 shall apply to threatened plants.
These provisions make it illegal for any person subject to the
jurisdiction of the United States to import or export, transport in
interstate or foreign commerce in the course of a commercial activity,
sell or offer for sale in interstate or foreign commerce, or to remove
and reduce to possession any such plant species from areas under
Federal jurisdiction. In addition, the Act prohibits malicious damage
or destruction of any such species on any area under Federal
jurisdiction, and the removal, cutting, digging up, or damaging or
destroying of any such species on any other area in knowing violation
of any State law or regulation, or in the course of any violation of a
State criminal trespass law. However, there is the following exception
for threatened plants. Seeds of cultivated specimens of species treated
as threatened shall be exempt from all the provisions of 50 CFR 17.61,
provided that a statement that the seeds are of ``cultivated origin''
accompanies the seeds or their container during the course of any
activity otherwise subject to these regulations. Exceptions to these
prohibitions are outlined in 50 CFR 17.72.
We may issue permits to carry out otherwise prohibited activities
involving endangered and threatened wildlife and plant species under
certain circumstances. Regulations governing permits are codified at 50
CFR 17.22 for endangered wildlife and at 17.62 and 17.72 for endangered
and threatened plants, respectively. With regard to endangered
wildlife, a permit must be issued for the following purposes: for
scientific purposes, to enhance the propagation or survival of the
species, and for incidental take in connection with otherwise lawful
activities. With regard to endangered plants, the Service may issue a
permit authorizing any activity otherwise prohibited by 50 CFR 17.61
for scientific purposes or for enhancing the propagation or survival of
endangered plants. With regard to threatened plants, a permit issued
under this section must be for one of the following: scientific
purposes, the enhancement of the propagation or survival of threatened
species, economic hardship, botanical or horticultural exhibition,
educational purposes, or other activities consistent with the purposes
and policy of the Act. Requests for copies of the regulations regarding
listed species and inquiries about prohibitions and permits may be
addressed to U.S. Fish and Wildlife Service, Pacific Region, Ecological
Services, Eastside Federal Complex, 911 NE. 11th Avenue, Portland, OR
97232-4181 (telephone 503-231-6131; facsimile 503-231-6243).
Our policy, as published in the Federal Register on July 1, 1994
(59 FR 34272), is to identify to the maximum extent practicable at the
time a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a proposed
listing on proposed and ongoing activities within the range of species
proposed for listing. The following activities could potentially result
in a violation of section 9 of the Act; this list is not comprehensive:
(1) Unauthorized collecting, handling, possessing, selling,
delivering, carrying, or transporting of the 23 species, including
import or export across State, Territory or Commonwealth lines and
international boundaries, except for properly documented antique
specimens of these taxa at least 100 years old, as defined by section
10(h)(1) of the Act;
(2) Introduction of nonnative species that compete with or prey
upon the nine animal species, such as the introduction of competing,
nonnative plants or animals to the Mariana Islands (U.S. Territory of
Guam and U.S. Commonwealth of the Northern Mariana Islands); and
(3) The unauthorized release of biological control agents that
attack any life stage of the nine animal species.
(4) Impacts to the nine animal species from destruction of habitat,
disturbance from noise (related to military training), and other
impacts from military presence.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Pacific
Islands Fish and Wildlife Office (see FOR FURTHER INFORMATION
[[Page 59411]]
CONTACT). Requests for copies of the regulations concerning listed
animals and general inquiries regarding prohibitions and permits may be
addressed to the U.S. Fish and Wildlife Service, Pacific Region,
Ecological Services, Endangered Species Permits, Eastside Federal
Complex, 911 NE. 11th Avenue, Portland, OR 97232-4181 (telephone 503-
231-6131; facsimile 503-231-6243).
If made final, Federal listing of the 23 species included in this
proposed rule may invoke Commonwealth and Territory listing under CNMI
and Guam Endangered Species laws (Title 85: Sec. 85-30.1-101 and 5 GCA
Sec. 63205, respectively) and supplement the protection available
under other local law. These protections would prohibit take of these
species and encourage conservation by both government agencies.
Further, the governments would be able to enter into agreements with
Federal agencies to administer and manage any area required for the
conservation, management, enhancement, or protection of endangered
species. Funds for these activities could be made available under
section 6 of the Act (Cooperation with the States and Territories).
Thus, the Federal protection afforded to these species by listing them
as endangered species would be reinforced and supplemented by
protection under Territorial and Commonwealth law.
Required Determinations
Clarity of the Rule
We are required by Executive Orders 12866 and 12988 and by the
Presidential Memorandum of June 1, 1998, to write all rules in plain
language. This means that each rule we publish must:
(1) Be logically organized;
(2) Use the active voice to address readers directly;
(3) Use clear language rather than jargon;
(4) Be divided into short sections and sentences; and
(5) Use lists and tables wherever possible.
If you feel that we have not met these requirements, send us
comments by one of the methods listed in ADDRESSES. To better help us
revise the rule, your comments should be as specific as possible. For
example, you should tell us the numbers of the sections or paragraphs
that are unclearly written, which sections or sentences are too long,
the sections where you feel lists or tables would be useful, etc.
National Environmental Policy Act (42 U.S.C. 4321 et seq.)
We have determined that environmental assessments and environmental
impact statements, as defined under the authority of the National
Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.), need not be
prepared in connection with listing a species as an endangered or
threatened species under the Endangered Species Act. We published a
notice outlining our reasons for this determination in the Federal
Register on October 25, 1983 (48 FR 49244).
References Cited
A complete list of references cited in this rulemaking is available
on the Internet at http://www.regulations.gov and upon request from the
Pacific Islands Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Authors
The primary authors of this proposed rule are the staff members of
the Pacific Islands Ecological Services Field Office.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Proposed Regulation Promulgation
Accordingly, we propose to amend part 17, subchapter B of chapter
I, title 50 of the Code of Federal Regulations, as set forth below:
PART 17--[AMENDED]
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; and 4201-4245;
unless otherwise noted.
0
2. Amend Sec. 17.11(h), the List of Endangered and Threatened
Wildlife, as follows:
0
a. By adding an entry for ``Bat, Pacific sheath-tailed'' (Emballonura
semicaudata rotensis), in alphabetical order under Mammals, to read as
set forth below;
0
b. By adding an entry for ``Skink, Slevin's'' (Emoia slevini), in
alphabetical order under Reptiles, to read as set forth below;
0
c. By adding an entry for ``Butterfly, Mariana eight-spot'' (Hypolimnas
octocula mariannensis), ``Butterfly, Mariana wandering'' (Vagrans
egistina), and ``Damselfly, Rota blue'' (Ischnura luta), in
alphabetical order under Insects, to read as set forth below; and
0
d. By adding an entry for ``Snail, fragile tree'' (Samoana fragilis)'',
``Snail, Guam tree'' (Partula radiolata), ``Snail, humped tree''
(Partula gibba), and ``Snail, Langford's tree'' (Partula langfordi), in
alphabetical order under Snails, to read as set forth below.
Sec. 17.11 Endangered and threatened wildlife.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species Vertebrate
-------------------------------------------------------- population where When Critical Special
Historic range endangered or Status listed habitat rules
Common name Scientific name threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mammals
* * * * * * *
Bat, Pacific sheath-tailed Emballonura U.S.A. (Guam, Entire............. E ........... NA NA
(Payesyes). semicaudata Mariana Islands).
rotensis.
* * * * * * *
Reptiles
* * * * * * *
Skink, Slevin's (Guali'ek Halom Emoia slevini....... U.S.A. (Guam, Entire............. E ........... NA NA
Tano). Mariana Islands).
[[Page 59412]]
* * * * * * *
Insects
* * * * * * *
Butterfly, Mariana eight-spot.... Hypolimnas octocula U.S.A. (Guam, Entire............. E ........... NA NA
mariannensis. Mariana Islands).
Butterfly, Mariana wandering..... Vagrans egistina.... U.S.A. (Guam, Entire............. E ........... NA NA
Mariana Islands).
* * * * * * *
Damselfly, Rota blue............. Ischnura luta....... U.S.A. (Mariana Entire............. E ........... NA NA
Islands).
* * * * * * *
Snails
* * * * * * *
Snail, fragile tree (Akaleha).... Samoana fragilis.... U.S.A. (Guam, Entire............. E ........... NA NA
Mariana Islands).
* * * * * * *
Snail, Guam tree (Akaleha)....... Partula radiolata... U.S.A. (Guam)...... Entire............. E ........... NA NA
Snail, humped tree (Akaleha)..... Partula gibba....... U.S.A. (Guam, Entire............. E ........... NA NA
Mariana Islands).
* * * * * * *
Snail, Langford's tree (Akaleha). Partula langfordi... U.S.A. (Mariana Entire............. E ........... NA NA
Islands).
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * *
0
3. Amend Sec. 17.12(h), the List of Endangered and Threatened Plants,
by adding entries for Bulbophyllum guamense, Cycas micronesica,
Dendrobium guamense, Eugenia bryanii, Hedyotis megalantha, Heritiera
longipetiolata, Maesa walkeri, Nervilia jacksoniae, Phyllanthus
saffordii, Psychotria malaspinae, Solanum guamense, Tabernaemontana
rotensis, Tinospora homosepala, and Tuberolabium guamense, in
alphabetical order under Flowering Plants, to read as set forth below.
Sec. 17.12 Endangered and threatened plants.
* * * * *
(h) * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Species
-------------------------------------------------------- Historic range Family Status When Critical Special
Scientific name Common name listed habitat rules
--------------------------------------------------------------------------------------------------------------------------------------------------------
Flowering Plants
* * * * * * *
Bulbophyllum guamense............ Cebello halumtano... U.S.A. (Guam, Orchidaceae........ E ........... NA NA
Mariana Islands).
* * * * * * *
Cycas micronesica................ Fadang.............. U.S.A. (Guam, Cycadaceae......... T ........... NA NA
Mariana Islands).
* * * * * * *
Dendrobium guamense.............. None................ U.S.A. (Guam, Orchidaceae........ E ........... NA NA
Mariana Islands).
* * * * * * *
Eugenia bryanii.................. None................ U.S.A. (Guam)...... Myrtaceae.......... E ........... NA NA
* * * * * * *
Hedyotis megalantha.............. Paudedo............. U.S.A. (Guam)...... Rubiaceae.......... E ........... NA NA
* * * * * * *
Heritiera longipetiolata......... Ufa-halomtano....... U.S.A. (Guam, Malvaceae.......... E ........... NA NA
Mariana Islands).
[[Page 59413]]
* * * * * * *
Maesa walkeri.................... None................ U.S.A. (Guam, Primulaceae........ E ........... NA NA
Mariana Islands).
* * * * * * *
Nervilia jacksoniae.............. None................ U.S.A. (Guam, Orchidaceae........ E ........... NA NA
Mariana Islands).
* * * * * * *
Phyllanthus saffordii............ None................ U.S.A. (Guam)...... Phyllanthaceae..... E ........... NA NA
* * * * * * *
Psychotria malaspinae............ Aplokating-palaoan.. U.S.A. (Guam)...... Rubiaceae.......... E ........... NA NA
* * * * * * *
Solanum guamense................. Bereng-henas U.S.A. (Guam, Solanaceae......... E ........... NA NA
halomtano. Mariana Islands).
* * * * * * *
Tabernaemontana rotensis......... None................ U.S.A. (Guam, Apocynaceae........ T ........... NA NA
Mariana Islands).
* * * * * * *
Tinospora homosepala............. None................ U.S.A. (Guam)...... Menispermaceae..... E ........... NA NA
* * * * * * *
Tuberolabium guamense............ .................... U.S.A. (Guam, Orchidaceae........ E ........... NA NA
Mariana Islands).
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dated: September 16, 2014.
Daniel M. Ashe,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2014-22776 Filed 9-30-14; 8:45 am]
BILLING CODE 4310-55-P