[Federal Register Volume 81, Number 196 (Tuesday, October 11, 2016)]
[Proposed Rules]
[Pages 70282-70308]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-24140]
[[Page 70281]]
Vol. 81
Tuesday,
No. 196
October 11, 2016
Part II
Department of the Interior
-----------------------------------------------------------------------
Fish and Wildlife Service
-----------------------------------------------------------------------
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; Proposed Threatened
Species Status for Sideroxylon reclinatum ssp. austrofloridense
(Everglades Bully), Digitaria pauciflora (Florida Pineland Crabgrass),
and Chamaesyce deltoidea ssp. pinetorum (Pineland Sandmat) and
Endangered Species Status for Dalea carthagenensis var. floridana
(Florida Prairie-Clover); Proposed Rule
Federal Register / Vol. 81 , No. 196 / Tuesday, October 11, 2016 /
Proposed Rules
[[Page 70282]]
-----------------------------------------------------------------------
DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2016-0090;4500030113]
RIN 1018-BB48
Endangered and Threatened Wildlife and Plants; Proposed
Threatened Species Status for Sideroxylon reclinatum ssp.
austrofloridense (Everglades Bully), Digitaria pauciflora (Florida
Pineland Crabgrass), and Chamaesyce deltoidea ssp. pinetorum (Pineland
Sandmat) and Endangered Species Status for Dalea carthagenensis var.
floridana (Florida Prairie-Clover)
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose
threatened species status under the Endangered Species Act of 1973
(Act), as amended, for Sideroxylon reclinatum ssp. austrofloridense
(Everglades bully), Digitaria pauciflora (Florida pineland crabgrass)
and Chamaesyce deltoidea ssp. pinetorum (pineland sandmat), and
endangered species status for Dalea carthagenensis var. floridana
(Florida prairie-clover). All four plants are from south Florida. If we
finalize this rule as proposed, it would extend the Act's protections
to these plants. The effect of this regulation will be to add these
species to the List of Endangered and Threatened Plants.
DATES: We will accept comments received or postmarked on or before
December 12, 2016. 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 25, 2016.
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-R4-ES-2016-0090,
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-R4-ES-2016-0090; U.S. Fish and Wildlife
Service 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: Roxanna Hinzman, Field Supervisor,
U.S. Fish and Wildlife Service, South Florida Ecological Services
Office, 1339 20th Street, Vero Beach, FL 32960, by telephone 772-562-
3909, or by facsimile 772-562-4288. 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 Act, if we determine that
a species is an endangered or threatened species throughout all or a
significant portion of its range, we are required to promptly publish a
proposal in the Federal Register and make a determination on our
proposal within 1 year. Listing a species as an endangered or
threatened species and designations and revisions of critical habitat
can only be completed by issuing a rule.
What this proposed rule does. This document proposes the listing of
the Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
and Chamaesyce deltoidea ssp. pinetorum as threatened species, and
Dalea carthagenensis var. floridana as an endangered species. The four
plants are currently 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 has until now been precluded by other higher
priority listing activities. This proposed rule reassesses all
available information regarding status of and threats to the four
plants.
The basis for our action. Under the Act, we may 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. We have determined that the threats to Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana
consist primarily of habitat loss and modification through urban and
agricultural development, and lack of adequate fire management (Factor
A) and proliferation of nonnative invasive plants, stochastic events
(hurricanes and storm surge), maintenance practices used on roadsides
and disturbed sites, and sea level rise (SLR) (Factor E).
We will seek peer review. We will seek comments from independent
specialists to ensure that our proposed designation is based on
scientifically sound data, assumptions, and analyses. We will invite
these peer reviewers to comment on our listing 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, other concerned governmental
agencies, Native American tribes, the scientific community, industry,
or any other interested parties concerning this proposed rule. We
particularly seek comments concerning:
(1) The four plants' biology, range, and population trends,
including:
(a) Biological or ecological requirements of these plants,
including habitat requirements for establishment, growth, and
reproduction;
(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 the plants, their
habitat, or both.
(2) Factors that may affect the continued existence of these
plants, 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 plants and existing regulations
that may be addressing those threats.
(4) Current or planned activities in the areas occupied by these
plants and
[[Page 70283]]
potential effects (positive or negative) of these activities on these
plants.
(5) Additional information concerning the biological or ecological
requirements of these plants, including pollination and pollinators.
(6) Additional information concerning the current and projected
effects of climate change, including sea level rise, on these plants
and their habitat.
(7) Scientific information or analysis informing whether these
plants more closely meet the definition of an endangered species or of
a threatened species under the Act.
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.
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, South Florida Ecological Services 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 for public hearings must be
received within 45 days after the date of publication of this proposed
rule in the Federal Register (see DATES). 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 will seek the expert
opinions of at least three appropriate and independent specialists
regarding this proposed rule. The purpose of peer review is to ensure
that our listing determination and critical habitat designation are
based on scientifically sound data, assumptions, and analyses. The peer
reviewers will have expertise in the biology, habitat, and conservation
status of these plants, to help inform our determination.
Previous Federal Actions
Digitaria pauciflora was first recognized as a candidate species on
September 27, 1985 (50 FR 39526). The 1990 Candidate Notice of Review
(CNOR) published in the Federal Register on February 21, 1990 (55 FR
6184), included Digitaria pauciflora as a candidate for listing under
the Act. We determined at that time that listing was warranted, but
precluded due to workloads and competing priorities.
Digitaria pauciflora remained on the candidate list as published in
the CNOR in 1993 (58 FR 51144, September 30, 1993). The CNOR was not
published again until October 25, 1999, and it retained Digitaria
pauciflora as a candidate and assigned a listing priority number (LPN)
of 6; the 1999 CNOR first recognized Chamaesyce deltoidea ssp.
pinetorum as a candidate and assigned an LPN of 12 and Dalea
carthagenensis var. floridana as a candidate and assigned an LPN of 3
(64 FR 57534). Candidate species are assigned LPNs based on immediacy
and magnitude of threats, as well as taxonomic status. The lower the
LPN, the higher priority that species is for us to determine
appropriate action using our available resources.
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, and
Dalea carthagenensis var. floridana remained on the candidate list from
2001 to 2004 (66 FR 54808, October 30, 2001; 67 FR 40657, June 13,
2002; 69 FR 24876, May 4, 2004). Sideroxylon reclinatum ssp.
austrofloridense was first recognized May 4, 2004, and was assigned an
LPN of 12 (69 FR 24876, May 4, 2004). We published a finding for
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana in the 2005 CNOR on May 11, 2005 (70 FR
24870), in response to a petition received on May 11, 2004.
All four species remained candidates from 2005 to 2015 (70 FR
24870, May 11, 2005; 71 FR 53756, September 12, 2006; 73 FR 75176,
December 10, 2008; 74 FR 57804, November 9, 2009; 75 FR 69222, November
10, 2010; 76 FR 66370, October 26, 2011; 77 FR 69994, November 21,
2012; 78 FR 70104, November 22, 2013; 79 FR 72450, December 5, 2014; 80
FR 80584, December 24, 2015).
On September 9, 2011, the Service entered into two settlement
agreements regarding species on the candidate list at that time
(Endangered Species Act Section 4 Deadline Litigation, No. 10-377
(EGS), MDL Docket No. 2165 (D.D.C. May 10, 2011)). This proposed
listing rule fulfills the requirements of those settlement agreements
for the 4 plant species.
Background
It is our intent to discuss below only those topics directly
relevant to the listing of Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, and Chamaesyce deltoidea ssp.
pinetorum as threatened species and Dalea carthagenensis var. floridana
as an endangered species in this proposed rule.
Sideroxylon reclinatum ssp. austrofloridense (Everglades bully)
Species Description
Corogin and Judd (2014, pp. 410-412) provide a detailed description
of Sideroxylon reclinatum ssp. austrofloridense. The plant is a single-
to many-stemmed shrub, 3-6 feet (ft) (1-2 meters (m)) tall. The
branches are smooth, slightly bent, and somewhat spiny. The leaves are
thin, oval-shaped, 0.8-2 inches (in) (2-5 centimeters (cm)) long,
evergreen, lance-shaped, and fuzzy on their undersides. The flowers are
in axillary cymes (Long and Lakela 1971, p. 679).
Sideroxylon reclinatum ssp. austrofloridense is distinguished from
the similar subspecies S. reclinatum ssp. reclinatum in Florida by its
leaves, which are persistently pubescent (fuzzy) on their undersides,
rather than smooth or pubescent only along the leaf midvein (Wunderlin
and Hansen 2003, p. 603). Corogin and Judd (2014, p. 404) indicated the
two subspecies are most reliably distinguished by differences in the
micromorphology of the leaf epidermis, and by the extent of
[[Page 70284]]
distribution of S. r. ssp. austrofloridense, which is limited to
extreme southern peninsular Florida.
Taxonomy
The genus Sideroxylon is represented by eight species in Florida.
All of these species were previously assigned to the genus Bumelia.
Sideroxylon reclinatum, the Florida bully, is represented by three
subspecies that range nearly throughout Florida and into neighboring
States. The Everglades subspecies was first recognized by Whetstone
(1985, pp. 544-547) as Bumelia reclinata var. austrofloridense, then
transferred to the genus Sideroxylon (Kartesz and Gandhi 1990, pp. 421-
427). Kartesz and Gandhi (1990, pp. 421-427) made Sideroxylon
reclinatum ssp. austrofloridense a subspecies rather than a variety;
however, in plant nomenclature, the ranks of variety and subspecies are
interchangeable. Sideroxylon reclinatum ssp. austrofloridense is used
in the current treatment of the Florida flora (Wunderlin and Hansen
2016, p. 1).
The Integrated Taxonomic Information System (2016, p. 1) indicates
that the taxonomic standing for Sideroxylon reclinatum ssp.
austrofloridense (Whetstone) Kartesz and Gandhi is accepted. The online
Atlas of Florida Vascular Plants (Wunderlin and Hansen 2016, p. 1) uses
the name S. reclinatum ssp. austrofloridense (Whetstone), as does
NatureServe (2016, p. 1).
Corogin and Judd (2014, p. 408) indicate that Sideroxylon
reclinatum subsp. austrofloridense is differentiated from S. reclinatum
subsp. reclinatum by a set of distinct characters at the
micromorphological level.
The two taxa are also separated eco-geographically. Sideroxylon
reclinatum subsp. austrofloridense is a narrow endemic, restricted to
pine rockland and marl prairie habitats in a well-defined area of
extreme southeastern peninsular Florida. Conversely, Sideroxylon
reclinatum subsp. reclinatum is more wide-ranging, occurring coastally
from southern Georgia west to Louisiana, and throughout Florida as far
south as Broward County in the east, and Collier and Monroe Counties in
the west. The only place where plants of both species overlap is within
Big Cypress National Preserve (BCNP), at the western fringe of
Everglades bully's range (Corrogin and Judd 2014, p. 409).
Climate
The climate of south Florida where Sideroxylon reclinatum ssp.
austrofloridense occurs is classified as tropical savanna and is
characterized by distinct wet and dry seasons and a monthly mean
temperature above 18 degrees Celsius ([deg]C) (64.4 degrees Fahrenheit
([deg]F)) in every month of the year (Gabler et al. 1994, p. 211).
Freezes can occur in the winter months, but are infrequent. Rainfall in
the area where Sideroxylon reclinatum ssp. austrofloridense occurs
varies from an annual average of 153-165 cm (60-65 in) in the northern
portion of the Miami Rock Ridge to an average of 140-153 cm (55-60 in)
in the southern portion. Approximately 75 percent of yearly rainfall
occurs during the wet season from June through September (Snyder et al.
1990, p. 238).
Habitat
Sideroxylon reclinatum ssp. austrofloridense grows in pine rockland
habitat, marl prairie habitat, and within the ecotone between both
habitats (Gann et al. 2006, p. 12; Bradley et al. 2013, p. 4, Gann
2015, p. 31). These habitats are maintained by regular fire, and are
prone, particularly marl prairie, to annual flooding for several months
during the wet season (Gann et al. 2006, p. 13; Bradley et al. 2013, p.
4). Sideroxylon reclinatum ssp. austrofloridense also grows on the
sunny edges of rockland hammock habitat (Gann 2015, p. 412), which is
fire-resistant. Historically, fire served to maintain the boundary
between pine rockland and rockland hammock by eliminating the
encroachment of hardwoods into pine rocklands. Absent natural or
prescribed fire, many pine rocklands have succeeded to rockland hammock
(FNAI 2010, p. 25). Canopy cover on the interior of rockland hammock is
too dense to support herbs and smaller shrub species, such as S. r.
ssp. austrofloridense, that require more sunlight.
Pine Rockland
Pine rockland is characterized by an open canopy of South Florida
slash pine (Pinus elliottii var. densa) with a patchy understory of
tropical and temperate shrubs and palms and a rich herbaceous layer of
mostly perennial species including numerous species endemic to South
Florida. Outcrops of weathered oolitic (small rounded particles or
grains) limestone, known locally as pinnacle rock, are common, and
solution holes may be present. This subtropical, pyrogenic flatland can
be mesic or xeric depending on landscape position and associated
natural communities (Florida Natural Areas Inventory (FNAI) 2010, p.
61).
Pine rockland has an open canopy of South Florida slash pine,
generally with multiple age classes. The diverse, open shrub and
subcanopy layer is composed of more than 100 species of palms and
hardwoods, most derived from the tropical flora of the West Indies
(FNAI 2010, p. 61). Many of these species vary in height depending on
fire frequency, getting taller with time since fire. These include saw
palmetto (Serenoa repens), cabbage palm (Sabal palmetto), silver palm
(Coccothrinax argentata), brittle thatch palm (Thrinax morrisii), wax
myrtle (Myrica cerifera), myrsine (Rapanea punctata), poisonwood
(Metopium toxiferum), locustberry (Byrsonima lucida), varnishleaf
(Dodonaea viscosa), tetrazygia (Tetrazygia bicolor), rough velvetseed
(Guettarda scabra), marlberry (Ardisia escallonioides), mangrove berry
(Psidium longipes), willow bustic (Sideroxylon salicifolium), and
winged sumac (Rhus copallinum). Short-statured shrubs include running
oak (Quercus elliottii), white indigoberry (Randia aculeata), Christmas
berry (Crossopetalum ilicifolium), redgal (Morinda royoc), and
snowberry (Chiococca alba).
Grasses, forbs, and ferns make up a diverse herbaceous layer
ranging from mostly continuous in areas with more soil development and
little exposed rock to sparse where more extensive outcroppings of rock
occur. Typical herbaceous species include bluestems (Andropogon spp.,
Schizachyrium gracile, S. rhizomatum, and S. sanguineum), arrowleaf
threeawn (Aristida purpurascens), lopsided indiangrass (Sorghastrum
secundum), hairawn muhly (Muhlenbergia capillaris), Florida white-top
sedge (Rhynchospora floridensis), pineland noseburn (Tragia saxicola),
devil's potato (Echites umbellata), pineland croton, several species of
sandmats (Chamaesyce spp.), partridge pea (Chamaecrista fasciculata),
coontie (Zamia pumila), maidenhair pineland fern (Anemia adiantifolia),
Bahama brake (Pteris bahamensis), and lacy bracken (Pteridium aquilinum
var. caudatum) (FNAI 2010, p. 62).
Pine rockland occurs on relatively flat, moderately to well drained
terrain from 2 to 7 m (6.5 to 23 ft) above sea level (FNAI 2010, p.
62). The oolitic limestone is at or very near the surface, and there is
very little soil development. Soils are generally composed of small
accumulations of nutrient-poor sand, marl, clayey loam, and organic
debris in depressions and crevices in the rock surface. Organic acids
occasionally dissolve the surface limestone causing collapsed
depressions in the surface rock called solution holes (FNAI 2010, p.
62). Drainage varies according to the porosity of the limestone
substrate, but is generally rapid. Consequently, most
[[Page 70285]]
sites are wet for only short periods following heavy rains. During the
rainy season, however, some sites may be shallowly inundated by slow-
flowing surface water for up to 60 days each year (FNAI 2010, p. 62).
Pine rockland is maintained by regular fire, and susceptible to
other natural disturbances such as hurricanes, frost events, and sea-
level rise (Ross et al. 1994, pp. 144-156). Fires historically burned
on an interval of approximately every 3 to 7 years (FNAI 2010, p. 63)
and were typically started by lightning strikes during the frequent
summer thunderstorms (FNAI 2010, p. 63).
Presently, prescribed fire must be periodically introduced into
pine rocklands to sustain community structure, prevent invasion by
woody species, maintain high herbaceous diversity (Loope and Dunevitz
1981, pp. 5-6; FNAI 2010, p. 63), and prevent succession to rockland
hammock. The amount of woody understory growth is directly related to
the length of time since the last fire. Herbaceous diversity declines
with time since last fire. The ecotone between pine rockland and
rockland hammock is abrupt when regular fire is present in the system.
However when fire is removed, the ecotone becomes more gradual and
subtle as hammock hardwoods encroach into the pineland (FNAI 2010, p.
63).
Marl Prairie
Marl prairie is a sparsely vegetated, grass-dominated community
found on marl substrates in South Florida. Marls are fine white
calcareous muds formed from calcite precipitated by a mixture of green
algae, blue green algae, and diatoms, known as periphyton. It is
seasonally inundated (2 to 4 months) to a shallow depth averaging about
20 cm (8 in). Marl prairie is a diverse community, which may contain
more than 100 species. Most of the marl prairie plant species
contribute little cover and more than 90 percent of the cover is
contributed by only two or three dominant species in any given area
(FNAI 2010, p. 107). Dominants may include one or more of the
following: Gulf hairawn muhly (Muhlenbergia sericea), spreading
beaksedge (Rhynchospora divergens), Florida little bluestem
(Schizachyrium rhizomatum), black bogrush (Schoenus nigricans),
Elliott's lovegrass (Eragrostis elliottii), sand cordgrass (Spartina
bakeri), and a short form of sawgrass (Cladium jamaicense) (Porter, Jr.
1967, pp. 937-942; FNAI 2010, p. 107). (Taxonomy of Schizachyrium and
Muhlenbergia follows treatments in Flora of North America (2007)).
Other characteristic species include southern beaksedge (Rhynchospora
microcarpa), bluejoint panicum (Panicum tenerum), Gulfdune paspalum
(Paspalum monostachyum), rosy camphorweed (Pluchea rosea), starrush
whitetop (Rhynchospora colorata), alligator lily (Hymenocallis
palmeri), arrowfeather threeawn (Aristida purpurascens), and narrowleaf
yellowtops (Flaveria linearis) (Porter, Jr. 1967, pp. 937-942; FNAI
2010, p. 107).
Marl prairie depends on a short hydroperiod of 2 to 4 months.
Longer hydroperiods favor the development of peat and the dominance of
sawgrass; shorter hydroperiods permit the invasion of woody species.
Marl prairie normally dries out during the winter and is subject to
fires at the end of the dry season; the most acres naturally burn in
May (FNAI 2010, p. 108). Fires at this time (in contrast to dormant
season fires) stimulate flowering of the dominant grasses (Main and
Barry 2002, pp. 430-434). The herbaceous species recover rapidly from
fire, and biomass reaches pre-fire levels at the end of 2 years. For
the first 2 years after fire, this community will burn only patchily,
if at all (FNAI 2010, p. 108). Reasons for the presence of dwarf
cypress in some marl prairies and not others are unknown (FNAI 2010, p.
108). Wade et al. (1980, pp. 67-79) estimated dwarf cypress stands in
marl prairie burn about once a decade due to low fire-carrying capacity
of their sparse understory.
Historical Range
All known historical and current records for Sideroxylon reclinatum
ssp. austrofloridense are summarized in table 1. The historical range
of S. reclinatum ssp. austrofloridense is limited to Collier, Miami-
Dade, and Monroe Counties, Florida. In Miami-Dade County, the plant was
known from central and southern Miami-Dade County along the Miami Rock
Ridge, which extends from Long Pine Key in the Everglades northward
through urban Miami to the Miami River. In Monroe County, the plant was
known from BCNP on the mainland, and was collected as far south as Key
Largo, in the Florida Keys. In Collier County, the species has been
recorded only within BCNP. This area constitutes a historical range of
approximately 42 miles (mi) (66 kilometers (km)) (Gann et al. 2002, p.
526; Corogin and Judd 2014, p. 412).
Current Range, Population Estimates, and Status
The current range of Sideroxylon reclinatum ssp. austrofloridense
is BCNP, the Long Pine Key region of Everglades National Park (ENP),
and pine rocklands adjacent to ENP (Hodges and Bradley 2006, p. 42;
Gann et al. 2006, p. 11; K. Bradley, pers. comm. 2007; J. Possley,
pers. comm. 2011a; 2011b; J. Sadle, pers. comm. 2011; Bradley et al.
2013, p. 4; Gann 2015, p. 30). The species is apparently extirpated
from Key Largo. Hodges and Bradley (2006, p. 42) did not find
Sideroxylon reclinatum ssp. austrofloridense in their surveys of pine
rocklands on Key Largo, Big Pine Key, Cudjoe Key, and Lower Sugarloaf
Key. This area constitutes a current range of approximately 42 mi (66
km) (Gann et al. 2002, p. 526; Corogin and Judd 2014, p. 412).
The largest population occurs at Long Pine Key in ENP (Hodges and
Bradley 2006, p. 42; Gann et al. 2006, p. 11; Gann 2015, p. 9). The
most recent information indicates that the baseline abundance estimate
at Long Pine Key based on a log10 abundance estimate is
10,000-100,000 plants (Gann et al. 2006, pp. 9-11; Gann 2015, p. 29).
Recent surveys of ENP have identified 14 occurrences of Sideroxylon
reclinatum ssp. austrofloridense in Long Pine Key, expanding the known
range in ENP (Gann 2015, p. 30).
In Miami-Dade County, outside ENP, pine rocklands tracts are orders
of magnitude smaller and exist in a matrix of agricultural, commercial,
and residential development. Possley and McSweeney (2005, p. 1)
observed approximately 73 plants at Larry and Penny Thompson Park,
within the Richmond Pine Rocklands. Possley (Fairchild Tropical Botanic
Garden (FTBG), pers. comm. 2011a; 2011b) found extant populations at
Quail Roost Pineland (two plants), Navy Well Pineland Preserve (four
plants), and Sunny Palms Pinelands (two plants). The species had been
observed in pine rocklands at Grant Hammock, and Pine Ridge Sanctuary
(Bradley et al. 2013, p. 1). The species no longer occurs at the Nixon-
Smiley Preserve.
Bradley et al. (2013, pp. 1-8) conducted surveys in the Gum Slough
region of Lostmans Pines in BCNP and reported finding Sideroxylon
reclinatum ssp. austrofloridense to have limited distribution within
the study area. Seventeen plants were counted within pine rockland
plots that were associated with marl prairie habitats (Bradley et al.
2013, p. 4).
[[Page 70286]]
Table 1--Summary of the Status and Trends of the Known Occurrences of Sideroxylon Reclinatum ssp.
Austrofloridense
----------------------------------------------------------------------------------------------------------------
Most recent
Population Ownership population Status Trend
estimate (Year)
----------------------------------------------------------------------------------------------------------------
Everglades National Park..... National Park 10,000- 100,000 Extant.......... Increasing.
Service. (2013).
Big Cypress National Preserve National Park 17 (2013)....... Extant.......... Insufficient data.
Service.
Larry Penny Thompson Park.... Miami-Dade 73 (2005)....... Extant.......... Insufficient data.
County.
Nixon-Smiley Preserve........ Miami-Dade 0 (Unknown)..... Extirpated...... ...........................
County.
Navy Wells Pineland Preserve. Miami-Dade 4 (2011)........ Extant.......... Insufficient data.
County.
Sunny Palms Pineland......... Miami-Dade 2 (2011)........ Extant.......... Insufficient data.
County.
Pine Ridge Sanctuary......... Private......... Unknown......... Extant.......... Insufficient data.
Lucille Hammock.............. Miami-Dade 11-100 (2007)... Extant.......... Insufficient data.
County.
South Dade Wetlands.......... Miami-Dade Unknown (2007).. Extant.......... Insufficient data.
County.
Natural Forest Community #P- Private......... 2-10 (2007)..... Extant.......... Insufficient data.
300.
Natural Forest Community #P- Private......... 11-100 (2007)... Extant.......... Insufficient data.
310.
Quail Roost Pineland......... Miami-Dade 2 (2011)........ Extant.......... Insufficient data.
County.
Grant Hammock................ Unknown......... Unknown Extirpated...... ...........................
(Unknown).
Key Largo.................... Unknown......... No estimate Extirpated...... ...........................
(1948).
----------------------------------------------------------------------------------------------------------------
Biology
Life History and Reproduction
Little is known about the life history of Sideroxylon reclinatum
ssp. austrofloridense, including pollination biology, seed production,
and dispersal (Gann 2015, p. 31). Reproduction is sexual, with new
plants generated from seeds. The species produces flowers from April to
May, and fruit ripen from June to July (Corogin and Judd 2014, pp. 410-
412). The plants can stand partial inundation with fresh water for a
portion of the year, but do not tolerate salinity.
Fire Ecology and Demography
There have been no detailed studies of Sideroxylon reclinatum ssp.
austrofloridense relationship towards fire; however, periodic fire is
extremely important to maintaining habitat for this species (Corogin
and Judd 2014, p. 414). Therefore, historical declines have been
partially attributed to habitat loss from fire suppression or
inadequate fire management (ENP 2014, p. 173).
Digitaria pauciflora (Florida pineland crabgrass)
Species Description
Digitaria pauciflora is a small perennial clump-grass, appearing
blue-green to gray with reddish-brown stems, typically 0.5-1 m (1.5-3
ft) tall (Small 1933, p. 51). The leaves form a subtle zig-zag pattern
as the leaf blades come off the stem at an angle. The leaf blades are
7-18 cm (2.8-7.1) in) long, 1.0-2.2 mm (0.04-0.08 in) wide, and number
2-8 per stem. Both the lower and upper surface and stems are hairy but
become glabrous (smooth or hairless) with age. The nodes are mostly
glabrous, the sheath auricles (an ear-like projection at the base of
the leaf) are 1.5 mm (0.06 in) long, and the sheaths are hairy but
becoming glabrous with age. The ligule (a small bract located at the
leaf-stem junction) is 1.5-2.0 mm (0.06-0.08 in) long. The flowers are
dull green, very small, and are borne on wispy spikes on the ends of
the leafy stems, with usually only a few flower clusters forming per
clump of grass. The lemma (a tiny bract adjacent to the flower) of
upper floret (flower) is purple. Stolons (aboveground horizontal stems)
are not present, but the plant produces rhizomes (belowground
horizontal stems) that allow for vegetative spread (Webster and Hatch,
1990, pp. 161-162). Digitaria pauciflora is known to reproduce sexually
(Bradley and Gann 1999, p. 50), with fruit production in the fall
(Wendelberger and Maschinski 2006, p. 3).
Taxonomy
Digitaria pauciflora was first described in 1928 based on specimens
collected in 1903 (Bradley and Gann 1999, p. 49). Small (1933, pp. 50-
51) later placed it in the genus Syntherisma. Subsequent authors
(Hitchcock 1935, p. 561; Webster & Hatch 1990, p. 161; Wunderlin 1998)
have retained it in the genus Digitaria (Bradley and Gann 1999, p. 49).
The online Atlas of Florida Vascular Plants uses the name Digitaria
pauciflora (Wunderlin and Hansen 2016, p. 1), the Integrated Taxonomic
System (ITIS 2016, p. 1), NatureServe (2016, p. 1), and the Florida
Department of Agriculture and Consumer Services (FDACS) (Coile and
Garland 2003, p. 19) indicates that its taxonomic status is accepted.
We have carefully reviewed all taxonomic data to determine that
Digitaria pauciflora is a valid taxon. The only synonym is Syntherisma
pauciflora (Hitchcock) Hitchcock ex Small (ITIS 2016, p. 1).
Climate
The climate of south Florida where Digitaria pauciflora occurs is
classified as tropical savanna, as described above for Sideroxylon
reclinatum ssp. austrofloridense.
Habitat
Digitaria pauciflora occurs predominantly within the seasonally
flooded ecotone between pine rockland and marl prairie, although the
species may overlap somewhat into both habitats (Bradley and Gann 1999,
p. 49; Fellows et al. 2002, p. 79). Plants can withstand inundation
with fresh water for one to several months each year (ENP 2014, p.
172). These habitats are maintained by regular fire, and are prone,
particularly marl prairie, to annual flooding for several months during
the wet season (Gann et al. 2006, p. 13). Pine rocklands and marl
prairies are described in detail above for Sideroxylon reclinatum ssp.
austrofloridense.
Historical Range
All known historical and current records for Digitaria pauciflora
are summarized in table 2. The historical range of D. pauciflora
consists of central and southern Miami-Dade County along the Miami Rock
Ridge, from the
[[Page 70287]]
southern Miami to Long Pine Key region of ENP, a range of approximately
42 mi (67.6 km) (Bradley and Gann 1999, p. 49). Specimens of D.
pauciflora were collected early in the twentieth century throughout
Miami-Dade County.
D. pauciflora was absent from collections from 1939 until 1973,
when it was rediscoverd at Long Pine Key in Everglades National Park
(Bradley and Gann 1999, p. 49). D. pauciflora has subsequently been
encountered consistently within Long Pine Key (Bradley and Gann 1999,
p. 49).
A single Digitaria pauciflora plant was discovered in 1995 within
marl prairie habitat at the Martinez Pinelands in the Richmond Pine
Rocklands, an area of Miami-Dade County that retains the largest
contiguous areas of pine rockland habitat outside of the Everglades.
However, this plant has since disappeared (Herndon 1998, p. 88; Bradley
and Gann 1999, p. 49; Gann 2015, p. 142). Three other historical
occurrences in Miami-Dade County have been documented: (1) a site
between Cutler and Longview Camp (last observed in 1903); (2) Jenkins
Homestead (date unspecified); and (3) South Miami (last observed in
1939) (K. Bradley, pers. comm. 2007); however, little is known
regarding the status of these populations. The species was not found
during a 2-year project to survey and map rare and exotic plants along
Florida Department of Transportation (FDOT) right-of-ways within Miami-
Dade and Monroe Counties (Gordon et al. 2007, pp. 1, 38).
Current Range, Population Estimates, and Status
The current range of Digitaria pauciflora includes ENP and BCNP
(Bradley and Gann 1999, p. 49; Gann et al. 2006, p. 3; Bradley, pers.
comm. 2005a; Gann 2015, p. 142). Ongoing surveys suggest the species
occurs throughout Long Pine Key of ENP (Gann et al. 2006, p. 7; 2015,
p. 144; Gann 2015, p. 144) and is much wider-ranging than previously
known in ENP. Joyce Maschinski (FTBG, pers. comm. 2007) characterized
the populations within ENP as abundant.
In 2002, Bradley et al. (2013, p. 2) discovered Digitaria
pauciflora within the Lostmans Pines region of BCNP in Monroe County.
This discovery represented the first known D. pauciflora occurrence
outside Miami-Dade County (FNAI 2007, p. 191). The species is widely
distributed within Lostmans Pines (Bradley et al. 2013, pp. 1-8).
Subsequent surveys for the species within BCNP have documented up to
nine occurrences, some of which contain an estimated 500-600 plants
(Maschinski et al. 2003, p. 141). Bradley et al. (2013, pp. 1-8)
conducted surveys in the Gum Slough region of Lostmans Pines and
indicated that the species is widely distributed within the study area.
A total of 2,365 plants was counted within pineland and sawgrass based
survey plots (Bradley et al. 2013, pp. 3-4). The range-wide population
estimate for D. pauciflora is 1,000-10,000 individuals at Long Pine Key
(Gann 2015, p. 142) and >10,000 individuals within BCNP (K. Bradley,
pers. comm. 2007). Large-scale stochastic events such as wildfire and
flooding can drastically reduce the size of D. pauciflora populations.
For example, in the spring months of 2016, wildfires in areas occupied
by D. pauciflora likely reduced populations in ENP. The populations
will likely rebound; however, regeneration could be severely hampered,
based on the amount and duration of flooding during the region's late
summer storm season. While Digitaria pauciflora populations remain
abundant within ENP and BCNP, these areas represent only half of the
species' historical range (Bradley and Gann 1999, p. 25; Gann 2015, p.
167). While D. pauciflora was known to occur throughout Miami-Dade
County, all other populations are likely extirpated.
Table 2--Summary of the Status and Trends of the Known Occurrences of Digitaria Pauciflora
----------------------------------------------------------------------------------------------------------------
Most recent
Population Ownership population Status Trend
estimate
----------------------------------------------------------------------------------------------------------------
Everglades National Park....... National Park 1,000-10,000 Extant............ Stable.
Service. (2007).
Big Cypress National Preserve.. National Park >10,000 (2007).... Extant............ Stable.
Service.
Martinez Pineland.............. Miami-Dade County. 0 (1999).......... Extirpated. ...................
Cutler and Longview Camp....... Unknown........... Unknown (1903).... Extirpated. ...................
Jenkins Homestead.............. Unknown........... Unknown (date Extirpated. ...................
unspecified).
South Miami.................... Unknown........... Unknown (1939).... Extirpated. ...................
----------------------------------------------------------------------------------------------------------------
Biology
Life History and Reproduction
Little is known about the life history of Digitaria pauciflora,
including pollination biology, seed production, and dispersal.
Reproduction is sexual, with new plants generated from seeds (Bradley
and Gann, 1999, p. 53). The species produces flowers from summer to
late fall on both new and older growth; some plants have been observed
to finish seeding as late as December (Fellows et al. 2002, p. 2; Gann
2015, p. 172). Plants can also spread clonally via rhizomes (Webster
and Hatch, 1990, pp. 161-162). The plants can stand partial inundation
with fresh water for a portion of the year, but do not tolerate
salinity.
Fire Ecology and Demography
Digitaria pauciflora population demographics and longevity have not
been studied (Bradley and Gann, 1999, p. 53; Fellows et al. 2002, p.
2). There have been no studies of the plant's relationship to fire;
however, periodic fire is extremely important to maintaining habitat
for this species (Bradley and Gann, 1999, p. 53; ENP 2014, p. 226).
Therefore, historical declines have been partially attributed to
habitat loss from fire suppression or inadequate fire management. Gann
(2015, p. 142) indicates that the species shows patch dynamics,
colonizing new areas and undergoing local extinctions with high rates
of turnover. Plants with `flashy' or `boom and bust' demographic
patterns are more susceptible to stochastic extinction events. ENP has
burned populations of D. pauciflora during the wet and dry season, and
both appear suitable to maintain populations of the plant (ENP 2014, p.
226).
Chamaesyce deltoidea spp. pinetorum (pineland sandmat)
Species Description
Chamaesyce deltoidea ssp. pinetorum is an ascending to erect
perennial herb. The stems are villous (hairy), and often reddish. The
leaf blades range from kidney-shaped or triangle-shaped and elliptic to
oval. The involucres (a cup-like structure enclosing the flowers) are 1
mm long, and pubescent, and possess green, even-edged glands with very
narrow appendages. The fruit is a 2-mm broad, pubescent capsule. The
seeds are 1 mm long, transversely wrinkled, and yellowish in color
(Small 1933, p. 795).
[[Page 70288]]
C. deltoidea ssp. pinetorum is known to reproduce sexually (Bradley and
Gann 1999, p. 25). Fruit production is year-round, with a peak in the
fall (Wendelberger and Maschinski 2006, p. 2).
Taxonomy
Chamaesyce deltoidea ssp. pinetorum was first described by Small in
1905, based on specimens collected in eastern Miami-Dade County (Small
1905, pp. 429-430). Initially, Small referred to these specimens as C.
pinetorum but recognized that it was closely related to Chamaesyce
deltoidea. Herndon (1993, pp. 38-51) included C. pinetorum within the
C. deltoidea complex, which is composed of three other taxa, two
occurring further north on the Miami Rock Ridge, and one occurring on
Big Pine Key in the lower Florida Keys (Monroe County). The three taxa
on the Miami Rock Ridge have distinct, but adjacent ranges.
Subsequently, Herndon (1993, pp. 38-51) has placed all four taxa at the
same taxonomic level, treating each as a distinct subspecies under
Chamaesyce deltoidea (C. deltoidea ssp. pinetorum; C. deltoidea ssp.
serpyllum, C. deltoidea ssp. adhaerens; C. deltoidea ssp. deltoidea).
Chamaesyce deltoidea ssp. deltoidea and C. deltoidea ssp. adhaerens
occur north of known C. deltoidea ssp. pinetorum populations, while
Chamaesyce deltoidea ssp. serpyllum is endemic to Big Pine Key.
Wunderlin and Hansen (2016, p. 1) follow Herndon's treatment in using
C. deltoidea ssp. pinetorum. Some modern authors place the genus
Chamaesyce into the genus Euphorbia sensu lato (Yang and Berry 2011,
pp. 1486-1503). Gann (2015, p. 168) indicates that if the pineland
sandmat is placed into the genus Euphorbia, the correct name is
Euphorbia deltoidea ssp. pinetorum.
The online Atlas of Florida Vascular Plants uses the name
Chamaesyce deltoidea ssp. pinetorum (Small) Herndon (Wunderlin and
Hansen 2016, p. 1). NatureServe (2016, p. 1) and FDACS (Coile and
Garland 2003, p. 11) indicate that C. deltoidea ssp. pinetorum is
accepted. However, the Integrated Taxonomic System (ITIS 2016, p. 1)
accepts Euphorbia deltoidea ssp. pinetorum as the scientific name for
the species (Gann 2015, p. 168). We have carefully reviewed all
taxonomic data and have determined that C. deltoidea ssp. pinetorum is
a valid taxon.
Climate
The climate of south Florida where Chamaesyce deltoidea ssp.
pinetorum occurs is classified as tropical savanna, as described above
for Sideroxylon reclinatum ssp. austrofloridense.
Habitat
Chamaesyce deltoidea ssp. pinetorum occurs in pine rocklands
(Bradley and Gann 1999, p. 24). Pine rocklands are maintained by
regular fire, and are prone to annual flooding for several months
during the wet season (Gann et al. 2006, p. 13). However, Gann (2015,
p. 169), indicates that C. deltoidea ssp. pinetorum generally occurs in
higher elevation pine rocklands at Long Pine Key in ENP, in areas
rarely subject to flooding. Pine rockland habitat is described in
detail above in the Habitat section for Sideroxylon reclinatum ssp.
austrofloridense.
Historical Range
All known historical and current records for Chamaesyce deltoidea
ssp. pinetorum are summarized in table 3. Chamaesyce deltoidea ssp.
pinetorum occurred historically only within the southern portion of the
Miami Rock Ridge, from the Richmond Pine Rocklands of southern Miami to
the Long Pine Key region of Everglades National Park, a range of
approximately 42 mi (67.6 km) (Bradley and Gann 1999, p. 24). C.
deltoidea ssp. pinetorum has been encountered consistently within Long
Pine Key, as well as in several County-owned conservation lands
adjacent to the ENP (Gann 2015, p. 167).
Current Range, Population Estimates, and Status
The current range of Chamaesyce deltoidea ssp. pinetorum is similar
to the historical range, although 98 percent of the pine rocklands (the
species' only habitat) outside of the ENP has been lost to development
(Kernan and Bradley 1996, p. 2). The total population size of
Chamaesyce deltoidea ssp. pinetorum is estimated to be between 14,500-
146,000 individuals, with the majority of the population occurring on
Long Pine Key (Bradley and Gann 1999, p. 25; Gann 2015, p. 167).
However, while Chamaesyce deltoidea ssp. pinetorum is most abundant
within ENP, pine rockland fragments outside of the Everglades represent
about half the species' extant range (Bradley and Gann 1999, p. 25;
Bradley pers. comm. 2007; Gann 2015, p. 167). Elsewhere in Miami-Dade
County, a 2011 survey of the privately owned Pine Ridge Sanctuary
confirmed the plant remains at this site (FNAI 2011, p. 5). A recent
survey of Larry and Penny Thompson Park located no individuals (J.
Possley, FTBG, pers. comm. 2011c).
Table 3--Summary of the Status and Trends of the Known Occurrences of Chamaesyce deltoidea ssp. pinetorum
----------------------------------------------------------------------------------------------------------------
Most recent
Population Ownderhip population Status Trend
estimate
----------------------------------------------------------------------------------------------------------------
Everglades National Park..... National Park 10,000-100,000 Extant.......... Increasing.
Service. (2011).
Florida City Pineland........ Miami-Dade 100-1,000 (2007) Extant.......... Increasing.
County.
Navy Wells................... Miami-Dade 1,000-10,000 Extant.......... Insufficient data.
County. (2007).
Navy Wells #2................ Miami-Dade 100-1,000 (2007) Extant.......... Insufficient data.
County.
Navy Wells #39............... Miami-Dade 1,000-10,000 Extant.......... Insufficient data.
County. (2007).
Palm Drive Pineland.......... Miami-Dade 10-100 (2007)... Extant.......... Insufficient data.
County.
Pine Ridge Sanctuary......... Private......... 10-100 (2011)... Extant.......... Insufficient data.
Rock Pit #39................. Miami-Dade 11-1,000 (2007). Extant.......... Insufficient data.
County.
Seminole Wayside Park........ Miami-Dade 100-1,000 (2007) Extant.......... Insufficient data.
County.
Fuchs Hammock Addition....... Miami-Dade 11-100 (2007)... Extant.......... Insufficient data.
County.
Sunny Palms Pineland......... Miami-Dade 100-1,000 (2007) Extant.......... Insufficient data.
County.
Larry and Penny Thompson Park Miami-Dade 0 (2011)........ Extirpated...... Insufficient data.
County.
John Kunkel Small Pineland... Institute for Present (2006).. Extant.......... Insufficient data.
Regional
Conservation.
Natural Forest Community Private......... 11-100 (2007)... Extant.......... Insufficient data.
[NFC] #P330.
[[Page 70289]]
Natural Forest Community Private......... 1,001-10,000 Extant.......... Insufficient data.
#P338. (2007).
Natural Forest Community Private......... 11-100 (2007)... Extant.......... Insufficient data.
#P339.
Natural Forest Community Private......... 11-100 (2007)... Extant.......... Insufficient data.
#P347.
Natural Forest Community Private......... 101-1,000 (2007) Extant.......... Insufficient data.
#P411.
Natural Forest Community Private......... 11-100 (2007)... Extant.......... Insufficient data.
#P413.
Natural Forest Community Private......... 11-100 (2007)... Extant.......... Insufficient data.
#P416.
Natural Forest Community Private......... 1,001-10,000 Extant.......... Insufficient data.
#P445. (2007).
----------------------------------------------------------------------------------------------------------------
Biology
Life History and Reproduction
Little is known about the life history of Chamaesyce deltoidea ssp.
pinetorum. Reproduction is sexual, but little is known about the
reproductive biology and ecology of the species (Bradley and Gann 1999,
p. 25; Gann 2015, p. 167). Herndon (1998, pp. 13-14) studied the life
history and population trends of C. deltoidea ssp. pinetorum and found
up to 88 percent of plants survived more than 3 years, showing that it
is a somewhat long-lived taxon. Herndon (1998, pp. 13-14) hypothesized
that some of the plants that had been recorded as dead may have instead
been in a cryptic phase (Gann 2015, p. 167). The extensive root system
of C. deltoidea ssp. pinetorum also suggests that it is a long-lived
plant (Maschinski et al. 2003, p. 179). Pollinators are unknown; other
species of Chamaesyce are completely reliant on insects for pollination
and seed production, while others are self-pollinating (Maschinski et
al. 2003, p. 179; Gann 2015, p. 168). Pollinators may include bees,
flies, ants, and wasps (Ehrenfeld 1979, p. 95; Gann 2015, p. 168).
Dispersal is unknown for Chamaesyce deltoidea ssp. pinetorum; however,
many seed capsules in similar Chamaesyce species are explosively
dehiscent, a form of dispersal that flings seeds far from the parent
plant (Maschinski et al., p. 179; Gann 2015, p. 168). This species is
known to flower and fruit year round (Wendelberger and Maschinski 2006,
p. 2). Peaks in fruiting for C. deltoidea ssp. pinetorum occur in the
fall and are stimulated by fire (Wendelberger and Maschinski 2006, p.
2). The plants can stand partial inundation with fresh water for a
portion of the year, but do not tolerate salinity.
Fire Ecology and Demography
There have been no studies of Chamaesyce deltoidea ssp. pinetorum
population demographics. However, the species is not shade tolerant,
and it requires periodic low-intensity fires to reduce competition by
woody species to maintain habitat for this species (Bradley and Gann,
1999, p. 26; ENP 2014, p. 170). Therefore, historical declines have
been partially attributed to habitat loss from fire suppression or
inadequate fire management.
Dalea carthagenensis var. floridana (Florida prairie-clover)
Species Description
Dalea carthagenensis var. floridana is a short-lived (less than 7
years) perennial shrub 2.6-9.8 ft (0.8-3.0 m) tall with a light-brown
woody stem and non-woody, light-brown or reddish branches. The leaves
are composed of 9-15 oval, gland-tipped leaflets, and are gland-dotted
on the underside. The flowers are in small loose heads at ends of
hairy, glandular stalks, less than 0.4 in long. The flower color is
white and maroon; each of the petals is different lengths and shapes.
The fruit is a small one-seeded pod, mostly enclosed by the hairy,
gland-dotted calyx (bracts at base of each flower) (adapted from Long
and Lakela 1971, p. 478; Bradley and Gann 1999, p. 42; Maschinski et
al. 2014, p. 44).
Taxonomy
Chapman (1886, p. 102) was the first to report this taxon in
Florida, calling it the tropical Dalea domingensis, based on specimens
collected on Key Biscayne. Small (1913, p. 89) accepted this
characterization but included the taxon in the genus Parosela, making
the plant P. domingensis. Rydberg (1920, p. x) renamed the plant,
calling it Parosela floridana, and this name was retained by Small
(1933, pp. 694-695). Clausen (1946a, p. 85) reviewed the taxonomy of
Florida and West Indian Dalea and considered them all to be the same
species. Clausen (1946a, p. 85) also found that the name D. domingensis
was a homonym of D. emphysodes, and published the name D. emphysodes
ssp. domingensis. Clausen (1946b, p. 572) later discovered that his use
of the name D. emphysodes was in error, and renamed the plants D.
carthagenensis ssp. domingensis. Long and Lakela (1971, p. 478)
accepted this usage. Barneby (1977), in a monograph of the genus, also
found that Florida plants were distinct from West Indian plants, citing
differences in leaf characters, naming the Florida species D.
carthagenensis var. floridana. Wunderlin (1998) has followed this
treatment.
The Integrated Taxonomic Information System (2016, p. 1) indicates
that the taxonomic standing for Dalea carthagenensis var. floridana
(Rydb.) Barneby is accepted. The online Atlas of Florida Vascular
Plants (Wunderlin and Hansen 2016, p. 1) uses the name D.
carthagenensis var. floridana, as does NatureServe (2016, p. 1). FDACS
uses the name Dalea carthagenensis and notes that D. carthagenensis
var. floridana is endemic (Coile and Garland 2003, p. 17). In summary,
there is consensus that D. carthagenensis var. floridana is a distinct
taxon. We have carefully reviewed the available taxonomic information
to reach the conclusion that D. carthagenensis var. floridana is a
valid taxon.
Climate
The climate of south Florida where Dalea carthagenensis var.
floridana occurs is classified as tropical savanna
[[Page 70290]]
as described above for Sideroxylon reclinatum ssp. austrofloridense.
Habitat
Dalea carthagenensis var. floridana grows in pine rockland,
rockland hammock, marl prairie, coastal berm, and in the ecotones
between these habitats (Bradley and Gann 1999, p. 43). The species may
also occur along roadsides within these habitats (Gann et al. 2006, p.
10). Pine rockland and marl prairie habitat are described in detail
above in the Habitat section for Sideroxylon reclinatum ssp.
austrofloridense.
Roadsides
Roadsides are a potentially important habitat for Dalea
carthagenensis var. floridana (Bradley and Gann 1999, p. 43). Where
endemics such as D. carthagenensis var. floridana are found on
shoulders, the ground cover is dominated mostly by native herbs and
grasses where exotic lawn grasses have not been planted. Maintaining
the roadsides in this condition through regular mowing, without
planting sod, should continue to provide suitable habitat for Dalea
carthagenensis var. floridana (Bradley 2006, p. 37).
Rockland Hammock
Rockland hammock is a species-rich tropical hardwood forest on
upland sites in areas where limestone is very near the surface and
often exposed. The forest floor is largely covered by leaf litter with
varying amounts of exposed limestone and has few herbaceous species.
Rockland hammocks typically have larger, more mature trees in the
interior, while the margins can be almost impenetrable in places with
dense growth of smaller shrubs, trees, and vines. Typical canopy and
subcanopy species include Bursera simaruba, Lysiloma latisiliquum
(false tamarind), Coccoloba diversifolia (pigeon plum), Sideroxylon
foetidissimum (false mastic), Ficus aurea (strangler fig), Piscidia
piscipula (Jamaican dogwood), Ocotea coriacea (lancewood), Drypetes
diversifolia, Simarouba glauca (paradisetree), Sideroxylon salicifolium
(willow bustic), Krugiodendron ferreum (black ironwood), Exothea
paniculata (inkwood), Metopium toxiferum, and Swietenia mahagoni (West
Indies mahogany). Mature hammocks may be open beneath a tall, well-
defined canopy and subcanopy. More commonly, in less mature or
disturbed hammocks, dense woody vegetation of varying heights from
canopy to short shrubs is often present. Species that generally make up
the shrub layers within rockland hammock include several species of
Eugenia (stoppers), Thrinax morrisii and T. radiata (thatch palms),
Amyris elemifera (sea torchwood), Ardisia escallonioides (marlberry),
Psychotria nervosa (wild coffee), Chrysophyllum oliviforme (satinleaf),
Sabal palmetto (cabbage palm), Guaiacum sanctum (lignum-vitae), Ximenia
americana (tallow wood), Colubrina elliptica (soldierwood),
Pithecellobium unguis-cati (cat claw blackbead) and Pithecellobium
keyense (Florida keys blackbead), Coccoloba uvifera (sea grape), and
Colubrina arborescens (greenheart). Vines can be common and include
Toxicodendron radicans (eastern poison ivy), Smilax auriculata (earleaf
greenbrier), Smilax havanensis (Everglades greenbrier), Parthenocissus
quinquefolia (Virginia creeper), Hippocratea volubilis (medicine vine),
and Morinda royoc (redgal). The typically sparse, short shrub layer may
include Zamia pumila (coontie) and Acanthocereus tetragonus (triangle
cactus). Herbaceous species are occasionally present and generally
sparse in coverage. Characteristic species include Lasiacis divaricata
(smallcane), Oplismenus hirtellus (basketgrass), and many species of
ferns (FNAI 2010, p. 24).
Rockland hammock occurs on a thin layer of highly organic soil
covering limestone on high ground that does not regularly flood, but it
is often dependent upon a high water table to keep humidity levels
high. Rockland hammocks are frequently located near wetlands; in the
Everglades they can occur on organic matter that accumulates on top of
the underlying limestone (FNAI 2010, p. 25).
Rockland hammock is susceptible to fire, frost, canopy disruption,
and ground water reduction. Rockland hammock can be the advanced
successional stage of pine rockland, especially in cases where rockland
hammock is adjacent to pine rockland. In such cases, when fire is
excluded from pine rockland for 15 to 25 years, it can succeed to
rockland hammock vegetation. Historically, rockland hammocks in south
Florida evolved with fire in the landscape. Fire most often
extinguished near the edges when it encountered the hammock's moist
microclimate and litter layer. However, rockland hammocks are
susceptible to damage from fire during extreme drought or when the
water table is lowered. In these cases, fire can cause tree mortality
and consume the organic soil layer (FNAI 2010, p. 25).
Rockland hammocks are also sensitive to the strong winds and storm
surge associated with infrequent hurricanes. Canopy damage often
occurs, which causes a change in the microclimate of the hammock.
Decreased relative humidity and drier soils can leave rockland hammocks
more susceptible to fire. Rockland hammock can transition into glades
marsh, mangrove swamp, salt marsh, coastal rock barren, pine rockland,
maritime hammock, or marl prairie (FNAI 2010, p. 26).
The sparsely vegetated edges or interior portions laid open by
canopy disruption are the areas of rockland hammock that have light
levels sufficient to support Dalea carthagenensis var. floridana.
However, the dynamic nature of the habitat means that areas not
currently open may become open in the future as a result of canopy
disruption from hurricanes, while areas currently open may develop more
dense canopy over time, eventually rendering that portion of the
hammock unsuitable for Dalea carthagenensis var. floridana.
Coastal Berm
Coastal berms are landscape features found along low-energy
coastlines in south Florida and the Florida Keys. Coastal berm is a
short forest or shrub thicket found on long, narrow, storm-deposited
ridges of loose sediment formed by a mixture of coarse shell fragments,
pieces of coralline algae, and other coastal debris. These ridges
parallel the shore and may be found on the seaward edge or landward
edge of the mangroves or farther inland depending on the height of the
storm surge that formed them. They range in height from 0.30 to 3.05 m
(1 to 10 ft). Structure and composition of the vegetation is variable
depending on height and time since the last storm event. The most
stable berms may share some tree species with rockland hammocks, but
generally have a greater proportion of shrubs and herbs. Tree species
may include Bursera simaruba (gumbo limbo), Coccoloba uvifera
(seagrape), Coccothrinax argentata (silver palm), Guapira discolor
(blolly), Drypetes diversifolia (milkbark), Genipa clusiifolia (seven
year apple), and Metopium toxiferum (poisonwood). Characteristic tall
shrub and short tree species include Eugenia foetida (Spanish stopper),
Ximenia americana (hog plum), Randia aculeata (white indigoberry),
Pithecellobium keyense (Florida Keys blackbead), and Sideroxylon
celastrinum (saffron plum). Short shrubs and herbs include Hymenocallis
latifolia (perfumed spiderlily), Capparis flexuosa (bayleaf capertree),
Lantana involucrata (buttonsage), and Rivina humilis
[[Page 70291]]
(rougeplant). More seaward berms or those more recently affected by
storm deposition may support a suite of plants similar to beaches,
including shoreline Sesuvium portulacastrum (sea purslane), Distichlis
spicata (saltgrass), and Sporobolus virginicus (seashore dropseed), or
scattered to dense shrub thickets with Conocarpus erectus (buttonwood),
stunted Avicennia germinans (black mangrove), Rhizophora mangle (red
mangrove), Laguncularia racemosa (white mangrove), Suriana maritima
(bay cedar), Manilkara jaimiqui (wild dilly), Jacquinia keyensis
(joewood), and Borrichia frutescens (bushy seaside oxeye) (Florida
Natural Areas Inventory (FNAI) 2010a, p. 1).
Coastal berms are deposited by storm waves along low-energy coasts.
Their distance inland depends on the height of the storm surge. Tall
berms may be the product of repeated storm deposition. Coastal berms
that are deposited far enough inland and remain long-undisturbed may in
time succeed to hammock. This is a structurally variable community that
may appear in various stages of succession following storm disturbance,
from scattered herbaceous beach-colonizing plants to a dense stand of
tall shrubs (FNAI 2010a, p. 2).
Historical Range
All known historical and current records for Dalea carthagenensis
var. floridana are summarized in table 4. The historical range of D.
carthagenensis var. floridana includes Miami-Dade, Monroe, Collier, and
Palm Beach Counties (Gann et al. 2015, pp. 25-26). There have been no
reports of this plant from Palm Beach County since 1918 (Bradley and
Gann 1999, p. 42). In Miami-Dade County, the species has been
extirpated from a number of historical locations, including Castellow
Hammock, ENP, the Coral Gables area, pinelands south of the Miami
River, and Cox Hammock (Bradley and Gann 1999, pp. 42-43; Maschinski et
al. 2014, p. 39). Gann et al. (2002, pp. 408-411) accounted for
essentially every herbarium specimen and reliable sighting. Gann (2015,
pp. 25-26) did not find D. carthagenensis var. floridana in ENP, and it
is presumed to be extirpated at this location. One of the previous
records at ENP was originally misidentified and has recently been
confirmed as a specimen of Aeschynomene pratensis (J. Sadle, NPS, pers.
comm. 2014). The other ENP herbarium specimen was correctly identified,
but the plant is currently considered to be extirpated from the
historical location (J. Sadle, NPS, pers. comm. 2014).
Current Range, Population Estimates, and Status
The current range of Dalea carthagenensis var. floridana includes
BCNP (Monroe and Collier Counties), three Miami-Dade County
conservation areas, and three unprotected lands within the Cutler Bay
region of Miami-Dade County (Maschinski et al. 2014, p. 39)
In 1999, Dalea carthagenensis var. floridana was rediscovered
within BCNP (Bradley and Gann 1999, p. 42). Maschinski et al. (2014, p.
31) subsequently surveyed the four extant populations on BCNP, finding
them at two locations. An area north of Oasis Visitor Center contained
236 plants (of various ages) and represents the largest extant
population within BCNP. The second extant population was in the
Pinecrest region (along Loop Road) of BCNP, an historic location within
the Park; however, only 17 plants were encountered. The species was not
found at 11-Mile Road, or at a second location along Loop Road during
the surveys.
Maschinski et al. (2014, pp. 31-34) have extensively surveyed
extant Dalea carthagenensis var. floridana populations at Charles
Deering Estate, R. Hardy Matheson Preserve, and Crandon Park within
Miami-Dade County over the past decade.
During 2003 to 2007, the population at Charles Deering Estate
ranged from between 50 and 80 individuals, with the number of seedlings
ranging from 3 to 54. However, beginning in 2008, Maschinski et al.
(2014, p. 33) have documented pulses in seedling establishment. In
2010, the total population size (seedlings and woody plants) was 356
individuals. The majority of these were seedlings and basal re-sprouts
from a fire that affected approximately one-third of the population
(Maschinski et al. 2010, p. 24). A 2014 survey found 347 plants,
suggesting the population remains stable (Maschinski et al. 2015, p.
30).
The population at R. Hardy Matheson Preserve had declined from 31
plants in 2004 to just 1 woody plant and 3 seedlings in 2008. However,
the population increased to 330 and 200 seedlings in 2009 and 2010,
respectively. The most recent surveys indicated stable populations of
98 and 307 individuals, in 2014 and 2015, respectively (Maschinski et
al. 2010, p. 30; 2014, p. 34).
In 2003, Dalea carthagenensis var. floridana was discovered within
coastal uplands at Crandon Park for the first time since 1966
(Maschinski et al. 2010, p. 28). The population at Crandon Park appears
to be stable; however, it is highly localized to a small area of
approximately 145 m\2\ (Possley and Maschinski 2009, p. 10). During
2007, FTBG initiated a demographic study of the species. Sampling plots
found 200 plants of various sizes, resulting in a population estimate
of 966 plants at the site (J. Maschinski, pers. comm. 2007; Possley and
Maschinski 2009, p. 10). Subsequent surveys have shown the population
to vary considerably, possibly due to a short lifespan or plant
dormancy (Possley and Maschinski 2009, p. 10). Surveys at Crandon Park
identified 288 and 168 individuals, in 2014 and 2015, respectively
(Maschinski et al. 2015, p. 32). Additional known populations within
Miami-Dade County are summarized in table 4.
Table 4--Summary of the Status and Trends of the Known Occurrences of Dalea carthagenensis var. floridana
----------------------------------------------------------------------------------------------------------------
Most recent
Population Ownership population Status Trend
estimate
----------------------------------------------------------------------------------------------------------------
Everglades National Park..... National Park ................ Extirpated ...........................
Service. (1964).
Big Cypress National National Park 236 (2013)...... Extant.......... Insufficient data.
Preserve, North of Oasis Service.
Visitor Center.
Big Cypress National National Park 0 (2013)........ Extirpated Insufficient data.
Preserve, 11-Mile Road. Service. (2014).
Big Cypress National National Park 17 (2013)....... Extant.......... Insufficient data.
Preserve, Pinecrest. Service.
Charles Deering Estate....... Miami-Dade 347 (2014)...... Extant.......... Stable.
County.
[[Page 70292]]
Virginia Key (reintroduction) City of Miami... 4 (2010)........ Extant.......... Insufficient data.
R. Hardy Matheson Preserve... Miami-Dade 307 (2015)...... Extant.......... Stable.
County.
Crandon Park................. Miami-Dade 168 (2015)...... Extant.......... Stable.
County.
Strawberry Fields Hammock Private......... 17 (2014)....... Extant.......... Insufficient data.
(next to Natural Forest
Community).
HRS, Inc..................... Private......... 21 (2014)....... Extant.......... Insufficient data.
Florida Power and Light Florida Power 2-10 (2007)..... Extant.......... Insufficient data.
property. and Light.
Coral Gables area............ Private......... ................ Extirpated ...........................
(1967).
Cox Hammock.................. Private......... ................ Extirpated ...........................
(1930).
Castellow Hammock Preserve... Miami-Dade ................ Extirpated ...........................
County. (1975).
Pineland South of Miami River Unknown......... Unknown......... Unknown. ...........................
Palm Beach County............ Private......... ................ Extirpated ...........................
(1918).
----------------------------------------------------------------------------------------------------------------
Biology
Life History and Reproduction
Dalea carthagenensis var. floridana appears to be a short-lived
(less than 7 years) perennial with a persistent seed bank (Maschinski
et al. 2014, p. 45). The species produces flowers from October to
March, and fruit ripen from November to April. The seed maturation
period is January to May, with a peak in February and March. Larger
plants can produce more than 500 seeds. Seedling recruitment varies
widely from year to year, with lower recruitment in drier years.
Seedlings and juveniles experience rapid growth in their first 2 years
(Maschinski et al. 2014, p. 45). The plants can stand partial
inundation with fresh water for a portion of the year, but do not
tolerate salinity.
Maschinski et al. (2014, p. 41) used ongoing survey data from the
Crandon Park population to conduct a preliminary population viability
analysis (PVA). The population at Crandon Park declined by 33 percent
from 2007 to 2009. High seedling recruitment increased numbers in 2010,
which stabilized the population until 2014, when a pulse of high
recruitment occurred. The demographic study indicated that 3 years had
declining population growth and 4 years were stable or increasing, a
cyclic pattern characteristic of short-lived species. The PVA indicated
that the external cues (temperature and soil moisture) required to
break dormancy positively influenced Dalea carthagenensis var.
floridana population dynamics. However, if coupled with seedling
mortality, serious population decline resulted. Low winter temperature
coupled with average rainfall resulted in high seedling recruitment and
good seedling survival; however, if high rainfall followed cold winter
temperatures, as was noted for winter 2010, seedling mortality was high
(Maschinski et al. 2014, p. 41).
Fire Ecology and Demography
There have been no studies of Dalea carthagenensis var. floridana
relationship to fire; however, periodic fire is extremely important to
maintaining habitat for this species (Maschinski et al. 2014, p. 47).
Therefore, historical declines have been partially attributed to
habitat loss from fire suppression or inadequate fire management.
Summary of Biological Status and Threats
The Act directs us to determine whether any species is an
endangered species or a threatened species because of any factors
affecting its continued existence. In this section, we summarize the
biological condition of each of the plant species and its resources,
and the influences on such, to assess the species' overall viability
and the risks to that viability.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana have experienced substantial destruction, modification, and
curtailment of their habitat and range (see Background, above).
Specific threats to these plants included in this factor include
habitat loss, fragmentation, and modification caused by development
(i.e., conversion to both urban and agricultural land uses) and
inadequate fire management. Each of these threats and its specific
effects on these plants are discussed in detail below.
Human Population Growth, Development, and Agricultural Conversion
The modification and destruction of the habitats that support
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana has been extreme in most areas of Miami-Dade and Monroe
Counties, thereby reducing the plants' current range and abundance in
Florida. The pine rockland community of south Florida, in which these
species primarily occur, is critically imperiled locally and globally
(FNAI 2010, p. 62). Destruction of pine rocklands and rockland hammocks
has occurred since the beginning of the 1900s. Extensive land-clearing
for human population growth, development, and agriculture in Miami-Dade
and Monroe Counties has altered, degraded, or destroyed thousands of
acres of these once-abundant ecosystems.
In Miami-Dade County, development and agriculture have reduced pine
rockland habitat by 90 percent in mainland south Florida. Pine rockland
habitat in Miami-Dade County, including ENP, was reduced to about 11
percent of its natural extent, from approximately 74,000 ha (183,000
ac) in the early 1900s, to only 8,140 ha (20,100 ac) in 1996 (Kernan
and Bradley 1996, p. 2). The largest remaining intact pine rockland
(approximately 2,313 ha (5,716
[[Page 70293]]
ac)) is Long Pine Key in ENP. Outside of ENP, only about 1 percent of
the pine rocklands on the Miami Rock Ridge have escaped clearing, and
much of what is left are small remnants scattered throughout the Miami
metropolitan area, isolated from other natural areas (Herndon 1998, p.
1). Habitat loss continues to occur in these plants' range, and most
remaining suitable habitat has been negatively altered through human
activity (illegal clearing, dumping), preclusion of fire, and
introduction of nonnative species.
Significant remaining pine rockland habitat occurs on private lands
and publicly owned lands that are not dedicated to or managed for
conservation. Species occurrences and suitable habitat remaining on
these lands are threatened by habitat loss and degradation, and threats
are expected to accelerate with increased development. The human
population within Miami-Dade County is currently greater than 2.4
million people, and the population is expected to grow to more than 4
million by 2060, an annual increase of roughly 30,000 people (Zwick and
Carr 2006, p. 20). Some of the known populations of Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana occur
on public conservation lands. Miami-Dade County has developed a network
of publicly owned conservation lands within Miami-Dade County, but
prescribed fire is lacking at many of these sites. ENP and BCNP
actively manage their respective pine rockland habitat with prescribed
fire (tables 1-4). However, any extant populations of these plants or
suitable habitat that may occur on non-conservation public or private
land, such as within the Richmond Pine Rocklands, are vulnerable to
habitat loss directly from development or indirectly by lack of
management.
The marl prairie habitat that also supports Sideroxylon reclinatum
ssp. austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana has similarly been
destroyed by the rapid development of Miami-Dade and Monroe Counties.
At least some of the occurrences reported from this habitat may be the
result of colonization that occurred after the habitat was artificially
dried-out due to local or regional drainage. Marl prairie on non-
conservation public or private land remains vulnerable to development,
which could lead to the loss of populations of the species.
Sideroxylon reclinatum ssp. austrofloridense occurs in numerous
pine rocklands outside of ENP within Miami-Dade County, most of which
are impacted be some degree by development. Two privately owned sites
in Miami-Dade County supporting Sideroxylon reclinatum ssp.
austrofloridense are vulnerable to habitat loss from development. Eight
sites that support the species are public land, which provides for some
management and protection. However, one population on public land, the
county-owned Nixon-Smiley Preserve, is extirpated due to inadequate
management.
Both extant populations of Digitaria pauciflora are located at ENP
and BCNP, which are public lands managed for conservation. However, D.
pauciflora is extirpated from four sites outside ENP and BCNP, which
comprise half of the species' historical range (Bradley and Gann 1999,
p. 25; Gann 2015, p. 167). Outside the protected lands of ENP and BCNP,
Digitaria pauciflora occurred throughout Miami-Dade County, including
as recently as 1995 within the pine rockland and marl prairie habitats
of the Martinez Pineland. Martinez Pineland is adjacent to several
other remnant pine rocklands that form the largest contiguous area of
pine rockland habitat in Miami-Dade County. However, D. pauciflora has
since disappeared (Herndon 1998, p. 88; Bradley and Gann 1999, p. 49)
from Martinez Pineland, and plans are being reviewed for development of
private portions (see discussion of Richmond Pine Rocklands, below).
Gordon et al. (2007, pp. 1, 38) did not document other extant D.
pauciflora populations during surveys to map rare and exotic plants
along FDOT right-of-ways within Miami-Dade and Monroe Counties. Three
other historical occurrences in Miami-Dade County had been documented;
however, no population estimates were made prior to these areas being
destroyed by habitat loss.
Eight populations of Chamaesyce deltoidea ssp. pinetorum located on
private land are vulnerable to habitat loss due to development. Ten
extant populations occur on public land and are largely protected from
development. A historical population of Chamaesyce deltoidea ssp.
pinetorum within Larry and Penny Thompson Park (also part of the
Richmond Pine Rocklands) has been extirpated due to lack of prescribed
fire (J. Possley, FTBG, pers. comm. 2011).
Dalea carthagenensis var. floridana has been extirpated from a
number of historical locations within Miami-Dade County, including ENP
for unknown reasons, and by development at Castellow Hammock, in the
Coral Gables area, the pinelands south of the Miami River, and Cox
Hammock (Bradley and Gann 1999, pp. 42-43; Maschinski et al. 2014, p.
39). In addition, there have been no reports of this species from Palm
Beach County since 1918, and this area is now densely developed
(Bradley and Gann 1999, p. 42). Six populations occur on public lands
and are protected from development. Three extant populations occur on
private land and are vulnerable to habitat loss from development.
Currently, there are plans to develop 55 ha (137 ac) of the largest
remaining parcel of pine rockland habitat in Miami-Dade County, the
Richmond Pine Rocklands, with a shopping center and residential
construction (Ram 2014, p. 2). Bradley and Gann (1999, p. 4) called the
345-ha (853-ac) Richmond Pine Rocklands, ``the largest and most
important area of pine rockland in Miami-Dade County outside of
Everglades National Park.'' Although both Digitaria pauciflora and
Chamaesyce deltoidea ssp. pinetorum have been extirpated from Richmond
Pine Rocklands, populations of Sideroxylon reclinatum ssp.
Austrofloridense, along with numerous other federally listed species,
still occur there.
The Miami-Dade County Department of Environmental Resources
Management has completed a management plan for portions of the Richmond
Pine Rocklands under a grant from the Service and is leading the
restoration and management of the Richmond Pine Rocklands (Bradley and
Gann 1999, p. 4). The developer has proposed to enter into a Habitat
Conservation Plan in conjunction with their plans to develop their
portion of the site and was required by Miami-Dade County Natural
Forest Community (NFC) regulations to set aside and manage 17 ha (43
ac) of pine rockland and associated habitats. A second project that
would result in the loss of pine rockland habitat has been proposed for
the Richmond Pine Rocklands. It includes expanding the Miami Zoo
complex to develop an amusement park and commercial entities. These
development projects will result in the loss of pine rockland habitat
that maintains a population of Sideroxylon reclinatum ssp.
austrofloridense as well as several federally listed species, and may
preclude future recovery options for the four plants (such as
compromising the land managers ability to burn within Richmond Pine
Rocklands).
Habitat Fragmentation
The remaining pine rocklands in the Miami metropolitan area are
severely
[[Page 70294]]
fragmented and isolated from each other. Habitat fragmentation reduces
the size of plant populations, and increases spatial isolation of
remnants. Barrios et al. (2011, p. 1062) investigated the effects of
fragmentation on a threatened pine rockland plant, Angadenia berteroi
(pineland golden trumpet), and found that abundance and fragment size
were positively related. Possley et al. (2008, p. 385) studied the
effects of fragment size on species composition in south Florida pine
rocklands, and found that plant species richness and fragment size were
positively correlated (although some small fragments supported nearly
as many species as the largest fragment). Composition of fragmented
habitat typically differs from that of intact forests, as isolation and
edge effects increase leading to increased abundance of disturbance-
adapted species (weedy species, nonnative invasive species) and lower
rates of pollination and propagule dispersal (Laurence and Bierregaard
1997, pp. 347-350.; Noss and Csuti 1997, pp. 284-299).
The degree to which fragmentation threatens the dispersal abilities
of Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana is unknown. In the historical landscape, where pine rockland
occurred within a mosaic of wetlands, water may have acted as a
dispersal vector for all pine rockland seeds. In the current fragmented
landscape, this type of dispersal would no longer be possible for any
of the Miami-Dade populations, because they exist in isolated habitat
patches surrounded by miles of unsuitable habitat (agriculture and
urban development) on every side. While additional dispersal vectors
may include animals and (in certain locations) mowing equipment, it is
likely that fragmentation has effectively reduced these plants' ability
to disperse.
While pollination research has not been conducted for Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana,
research regarding other species and ecosystems provides valuable
information regarding potential effects of fragmentation to these
plants. Effects of fragmentation may include changes to the pollinator
community as a result of limitation of pollinator-required resources
(e.g., reduced availability of rendezvous plants, nesting and roosting
sites, and nectar/pollen); these changes may include changes to
pollinator community composition, species abundance and diversity, and
pollinator behavior (Rathcke and Jules 1993, pp. 273-275; Kremen and
Ricketts 2000, p. 1227; Harris and Johnson 2004, pp. 30-33). As a
result, plants in fragmented habitats may experience lower visitation
rates, which in turn may result in reduced seed production of the
pollinated plant (which may lead to reduced seedling recruitment),
reduced pollen dispersal, increased inbreeding, reduced genetic
variability, and ultimately reduced population viability (Rathcke and
Jules 1993, p. 275; Goverde et al. 2002, pp. 297-298; Harris and
Johnson 2004, pp. 33-34).
The effects of fragmentation on fire go beyond edge effects and
include reduced likelihood and extent of fires, and altered behavior
and characteristics (e.g., intensity) of those fires that do occur.
Habitat fragmentation encourages the suppression of naturally occurring
fires, and has prevented fire from moving across the landscape in a
natural way, resulting in an increased amount of habitat suffering from
these negative impacts. High fragmentation of small habitat patches
within an urban matrix discourages the use of prescribed fire as well
due to logistical difficulties (see Fire Management, below).
Forest fragments in urban settings are also subject to increased
likelihood of certain types of human-related disturbance, such as the
dumping of trash (Chavez and Tynon 2000, p. 405) and illegal clearing.
The many effects of habitat fragmentation may work in concert to
threaten the local persistence of a species, especially of small
populations (see discussion below); when a species' range of occurrence
is limited, as with these four plants, threats to local persistence
increase extinction risk.
Fire Management
One of the primary threats to Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana is habitat
modification and degradation through inadequate fire management, which
includes both the lack of prescribed fire and suppression of natural
fires. Where the term ``fire-suppressed'' is used below, it describes
degraded pine rockland conditions resulting from a lack of adequate
fire (natural or prescribed) in the landscape. Historically, frequent
(approximately twice per decade), lightning-induced fires were a vital
component in maintaining native vegetation and ecosystem functioning
within south Florida pine rocklands (see Status Assessment, above). A
period of just 10 years without fire may result in a marked decrease in
the number of herbaceous species due to the effects of shading and
litter accumulation (FNAI 2010, p. 63). Exclusion of fire for
approximately 25 years will likely result in gradual hammock
development over that time period, leaving a system that is very fire
resistant if additional pre-fire management (e.g., mechanical hardwood
removal) is not undertaken.
Today, natural fires are unlikely to occur or are likely to be
suppressed in the remaining, highly fragmented pine rockland habitat.
The suppression of natural fires has reduced the size of the areas that
burn, and habitat fragmentation has prevented fire from moving across
the landscape in a natural way. Without fire, successional climax from
pine rockland to rockland hammock takes 10 to 25 years, and
displacement of native species by invasive nonnative plants often
occurs. All occurrences of Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana are affected by some
degree of inadequate fire management, with the primary threat being
shading by hardwoods (Bradley and Gann 1999, p. 15; Bradley and Gann
2005, page numbers not applicable). Shading may also be caused by a
fire-suppressed (and, in some cases, planted) pine canopy that has
evaded the natural thinning effects that fire has on seedlings and
smaller trees. Gann (2013, pers. comm.) indicates this is also a threat
to pine rockland habitat on the Miami Rock Ridge. Understory plants
such as Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana are shaded out after just 10 years
without fire, by hardwoods and nonnatives alike.
Whether the dense canopy is composed of pine, hardwoods,
nonnatives, or a combination, seed germination and establishment are
inhibited in fire-suppressed habitat due to accumulated leaf litter,
which also changes soil moisture and nutrient availability (Hiers et
al. 2007, pp. 811-812). This alteration to microhabitat can also
inhibit seedling establishment as well as negatively influence flower
and fruit production (Wendelberger and Maschinski 2009, pp. 849-851),
thereby reducing sexual reproduction in fire-adapted species such as
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana (Geiger 2002, pp. 78-79, 81-83).
[[Page 70295]]
After an extended period of inadequate fire management in pine
rocklands, it becomes necessary to control invading native hardwoods
mechanically, since excess growth of native hardwoods would result in a
hot fire, which can cause mortality of pines and destroys the
rootstocks and seed banks of other native plants. Mechanical treatments
cannot entirely replace fire because pine trees, understory shrubs,
grasses, and herbs all contribute to an ever-increasing layer of leaf
litter, covering herbs and preventing germination, as discussed above.
Leaf litter will continue to accumulate even if hardwoods are removed
mechanically. In addition, the ashes left by fires provide important
post-fire nutrient cycling, which is not provided via mechanical
removal.
The impacts of fire on Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana are not entirely
understood. Fire is critical in maintaining the open understory and
species diversity in pine rocklands and marl prairies where these
species occur, as well as to reduce populations of nonnative plant
species. Fire maintains the ecotone (transition) between saw grass
marsh, pine rockland, and rockland hammock habitats where S. reclinatum
ssp. austrofloridense grows.
Some natural mortality of Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana may occur from fire,
especially more intense fires. S. reclinatum ssp. austrofloridense and
C. deltoidea ssp. pinetorum grow in wet marl soils and soil deposits
within cracks in the limestone bedrock, which provides protection to
the roots and allows plants to resprout following fire. C. deltoidea
ssp. pinetorum, in particular, possesses a well-developed rootstock
that is protected from fire (ENP 2014, p. 203). Herndon (1998, p. 28)
pointed out that the life history of C. deltoidea ssp. pinetorum
includes a cryptic stage, making interpretation of mortality of
aboveground parts difficult.
Currently, limited information is available on differences in
mortality or long-term population impacts of Sideroxylon reclinatum
ssp. austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana resulting from wet
or dry season burns. Indirect evidence suggests that burning in either
season is suitable to maintain populations of S. reclinatum ssp.
austrofloridense, D. pauciflora, and C. deltoidea ssp. pinetorum in
pine rocklands. Prescribed fire in ENP was originally conducted during
the dry season. Fire management was gradually shifted to wet-season
burning in an effort to better mimic natural lightning-ignited fire
patterns. As a result, pinelands and marl prairies in ENP where S.
reclinatum ssp. austrofloridense, D. pauciflora, and C. deltoidea ssp.
pinetorum occur have been burned in both the wet season and dry season.
Long-term maintenance of populations in those areas indicates that
either practice will sustain populations of these species.
Federal (Service, NPS), State (Florida Department of Environmental
Protection (FDEP), Florida Fish and Wildlife Conservation Commission
(FWC), and County (Miami-Dade DERM) land managers, and nonprofit
organizations (Institute for Regional Conservation (IRC)) implement
prescribed fire on public and private lands within the ranges of
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana. While management of some County conservation lands includes
regular burning, other lands remain severely fire-suppressed. Even in
areas under active management, some portions are typically fire-
suppressed. Nevertheless, all of these sites retain a contingent of
native species and a seedbank capable of responding to fire.
While ENP, BCNP, and various Miami-Dade County conservation lands
(e.g., Navy Wells Pineland Preserve) each attempt to administer
prescribed burns, the threat of inadequate fire management still
remains. The pine rocklands in the Long Pine Key region of ENP remained
largely fire-suppressed for the past decade as the Park updated its
fire management plan. Although prescribed fire was returned to Long
Pine Key in early 2016, many areas retained substantial amounts of
unburned understory vegetation. As a result, despite reintroduction of
a fire regime, several large-scale wildfires ignited during the spring
months of 2016, which burned up to 50 percent of the pine rocklands in
Long Pine Key. Ultimately, this combination of prescribed burns and
natural fires (if not too hot or lasting too long) is likely to improve
conditions for Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, and Chamaesyce deltoidea ssp. pinetorum populations within
ENP. For example, at 3 to 6 months post-burn, these species appear to
be recolonizing burned areas (Sadle, pers. comm. 2016; Salvato, pers.
obs. 2016). However, this chain of events also demonstrated the threat
that prolonged or insufficient fire management may pose to local
populations of an imperiled species, even on public conservation lands.
Implementation of a prescribed fire program in Miami-Dade County
has been hampered by a shortage of resources, and by logistical
difficulties and public concern related to burning next to residential
areas. Many homes have been built in a mosaic of pine rockland, so the
use of prescribed fire in many places has become complicated because of
potential danger to structures and smoke generated from the burns.
Nonprofit organizations such as IRC have similar difficulties in
conducting prescribed burns due to difficulties with permitting and
obtaining the necessary permissions as well as hazard insurance
limitations (Gann 2013, pers. comm.). Few private landowners have the
means and/or desire to implement prescribed fire on their property, and
doing so in a fragmented urban environment is logistically difficult
and may be costly. One of the few privately owned pine rocklands that
is successfully managed with prescribed burning is Pine Ridge
Sanctuary, located in a more agricultural (less urban) matrix of Miami-
Dade, which was last burned in November 2010 (Glancy 2013, pers. comm.)
and retains populations of both Sideroxylon reclinatum ssp.
austrofloridense and Chamaesyce deltoidea ssp. pinetorum. Similarly,
extant populations of Dalea carthagenensis var. floridana within the
privately owned Charles Deering Estate and County-owned Crandon Park,
are managed with fire.
Conservation Efforts To Reduce the Present or Threatened Destruction,
Modification, or Curtailment of Habitat or Range
Miami-Dade County Environmentally Endangered Lands Covenant Program
In 1979, Miami-Dade County enacted the Environmentally Endangered
Lands (EEL) Covenant Program, which reduces taxes for private
landowners of natural forest communities (NFCs; pine rocklands and
tropical hardwood hammocks) who agree not to develop their property and
manage it for a period of 10 years, with the option to renew for
additional 10-year periods (Service 1999, p. 3-177). Although these
temporary conservation easements provide valuable protection for their
duration, they are not considered under Factor D, below, because they
are voluntary agreements and not regulatory in nature. Miami-Dade
County currently has approximately 59 pine rockland properties enrolled
in this program,
[[Page 70296]]
preserving 69.4 ha (172 ac) of pine rockland habitat (Johnson 2012,
pers. comm.). The program also has approximately 21 rockland hammocks
properties enrolled in this program, preserving 20.64 ha (51 ac) of
rockland hammock habitat (Joyner 2013b, pers. comm.). The vast majority
of these properties are small, and many are in need of habitat
management such as prescribed fire and removal of nonnative invasive
plants. Thus, while EEL covenant lands have the potential to provide
valuable habitat for these plants and reduce threats in the near term,
the actual effect of these conservation lands is largely determined by
whether individual land owners follow prescribed EEL management plans
and NFC regulations (see Local under Factor D).
Fee Title Properties
In 1990, Miami-Dade County voters approved a 2-year property tax to
fund the acquisition, protection, and maintenance of natural areas by
the EEL Program. The EEL Program purchases and manages natural lands
for preservation. Land uses deemed incompatible with the protection of
the natural resources are prohibited by current regulations; however,
the County Commission ultimately controls what may happen with any
County property, and land use changes may occur over time (Gil 2013,
pers. comm.). To date, the Miami-Dade County EEL Program has acquired a
total of approximately 313 ha (775 ac) of pine rockland, and 95 ha (236
ac) of rockland hammocks (Guerra 2015 pers. comm.; Gil 2013, pers.
comm.). The EEL Program also manages approximately 314 ha (777 ac) of
pine rocklands and 639 ha (1,578 ac) of rockland hammocks owned by the
Miami-Dade County Parks, Recreation and Open Spaces Department,
including some of the largest remaining areas of pine rockland habitat
on the Miami Rock Ridge outside of ENP (e.g., Larry and Penny Thompson
Park, Zoo Miami pinelands, and Navy Wells Pineland Preserve), and some
of the largest remaining areas of rockland hammocks (e.g., Matheson
Hammock Park, Castellow Hammock Park, and Deering Estate Park and
Preserves).
Conservation efforts in Miami's EEL Preserves have been under way
for many years. In Miami-Dade County, conservation lands are and have
been monitored by FTBG and IRC, in coordination with the EEL Program,
to assess habitat status and determine any changes that may pose a
threat to or alter the abundance of these species. Impacts to habitat
via nonnative species and natural stochastic events are monitored and
actively managed in areas where the taxon is known to occur. These
programs are long term and ongoing in Miami-Dade County; however,
programs are limited by the availability of annual funding. In
particular, fire management remains inadequate at many sites.
Since 2005, the Service has funded IRC to facilitate restoration
and management of privately owned pine rockland habitats in Miami-Dade
County. These programs included prescribed burns, nonnative plant
control, light debris removal, hardwood management, reintroduction of
pines where needed, and development of management plans. One of these
programs, called the Pine Rockland Initiative, includes 10-year
cooperative agreements between participating landowners and the
Service/IRC to ensure restored areas will be managed appropriately
during that time. Although most of these objectives have been achieved,
IRC has not been able to conduct the desired prescribed burns, due to
logistical difficulties as discussed above (see Fire Management).
Connect To Protect Program
FTBG, with the support of various Federal, State, local, and
nonprofit organizations, has established the ``Connect to Protect
Network.'' The objective of this program is to encourage widespread
participation of citizens to create corridors of healthy pine rocklands
by planting stepping stone gardens and rights-of-way with native pine
rockland species, and restoring isolated pine rockland fragments. By
doing this, FTBG hopes to increase the probability that pollination and
seed dispersal vectors can find and transport seeds and pollen across
developed areas that separate pine rockland fragments to improve gene
flow between fragmented plant populations and increase the likelihood
that these plants will persist over the long term. Although these
projects may serve as valuable components toward the conservation of
pine rockland species and habitat, they are dependent on continual
funding, as well as participation from private landowners, both of
which may vary through time.
National Park Service Lands
The NPS General Management Plans (GMPs) for ENP (NPS 2015) and BCNP
(BCNP 2008) serve to protect, restore, and maintain natural and
cultural resources at the ecosystem level. Although these GMPs are not
regulatory, and their implementation is not mandatory, they do include
conservation measures for Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, or Dalea
carthagenensis var. floridana.
Summary of Factor A
We have identified a number of threats to the habitat of the
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana that have operated in the past, are impacting these species
now, and will continue to impact them in the future. Habitat loss,
fragmentation, and degradation and associated pressures from increased
human population are major threats; these threats are expected to
continue, placing these plants at greater risk. Sideroxylon reclinatum
ssp. austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana may be impacted when
pine rocklands are converted to other uses or when lack of fire causes
the conversion to hardwood hammocks or other unsuitable habitats.
On public lands, including Service, NPS, and Miami-Dade County-
owned lands, implementation of prescribed fire has not been sufficient
because of legal constraints (permitting requirements) and inadequate
funding. Any populations of these four plants found on private property
could be destroyed due to lack of protection. Although efforts are
being made to conserve natural areas and apply prescribed fire, most
pine rocklands remain in poor fire condition, and the long-term effects
of large-scale and wide-ranging habitat modification, destruction, and
curtailment will last into the future, while ongoing habitat loss due
to population growth, development, and agricultural conversion
continues to pose a threat to these species outside of conservation
lands.
Therefore, based on the best information available, we have
determined that the threats to Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana from habitat
destruction, modification, or curtailment are occurring throughout the
entire range of these species and are expected to continue into the
future.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The best available data do not indicate that overutilization for
commercial, recreational, scientific, or
[[Page 70297]]
educational purposes are a threat to Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, or Dalea carthagenensis var. floridana. Threats to these
plants related to other aspects of recreation and similar human
activities (i.e., not related to overutilization) are discussed in
Factor E.
Factor C. Disease or Predation
No diseases or incidences of predation have been reported for
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, or Dalea carthagenensis var.
floridana.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
Under this factor, we examine whether threats to these plants that
are discussed under the other factors are continuing due to an
inadequacy of an existing regulatory mechanism. Section 4(b)(1)(A) of
the Act requires the Service to take into account ``those efforts, if
any, being made by any State or foreign nation, or any political
subdivision of a State or foreign nation, to protect such species. . .
.'' In relation to Factor D, we interpret this language to require the
Service to consider relevant Federal, State, and tribal laws,
regulations, and other such mechanisms that may minimize any of the
threats we describe in threat analyses under the other four factors, or
otherwise enhance conservation of the species. We give strongest weight
to statutes and their implementing regulations and to management
direction that stems from those laws and regulations. An example would
be State governmental actions enforced under a State statute or
constitution or Federal action under statute.
Having evaluated the impact of the threats as mitigated by any such
conservation efforts, we analyze under Factor D the extent to which
existing regulatory mechanisms address the specific threats to the
species. Regulatory mechanisms, if they exist, may reduce or eliminate
the impacts from one or more identified threats. In this section, we
review existing Federal, State, and local regulatory mechanisms to
determine whether they effectively reduce or remove threats to
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana.
Federal
Populations of Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana within the Everglades and ENP and BCNP
are protected by NPS regulations at 36 CFR 2.1, which prohibit visitors
from harming or removing plants, listed or otherwise, from ENP or BCNP.
However, the regulation does not address actions taken by NPS that
cause mortality, or habitat loss or modification. NPS regulations do
not require the application of prescribed fire or voluntary recovery
actions for listed species.
In addition to occurring on ENP and BCNP, Sideroxylon reclinatum
ssp. austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana may occur (we do not
have recent surveys) on Federal lands within the Richmond Pine
Rocklands, including lands owned by the U.S. Coast Guard and the
National Oceanic and Atmospheric Association (NOAA; small portion of
Martinez Pineland). There are no Federal protections for candidate
species, including these four plants, on these properties. Otherwise,
these plants occur primarily on State, County, or private land (Tables
1-4), and development of these areas will likely require no Federal
permit or other authorization. Therefore, projects that affect them are
usually not analyzed under the National Environmental Policy Act (NEPA)
(42 U.S.C. 4321 et seq.).
State
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana are listed on the Sate of Florida's Regulated Plant Index as
endangered under Chapter 5B-40, Florida Administrative Code. This
listing provides little or no habitat protection beyond the State's
Development of Regional Impact process, which discloses impacts from
projects, but provides no regulatory protection for State-listed plants
on private lands.
Florida Statutes 581.185 sections (3)(a) and (b) prohibit any
person from willfully destroying or harvesting any species listed as
endangered or threatened on the Index, or growing such a plant on the
private land of another, or on any public land, without first obtaining
the written permission of the landowner and a permit from the Florida
Department of Plant Industry. The statute further provides that any
person willfully destroying or harvesting; transporting, carrying, or
conveying on any public road or highway; or selling or offering for
sale any plant listed in the Index as endangered must have a permit
from the State at all times when engaged in any such activities.
However, subsections (8)(a) and (b) of the statute waive State
regulation for certain classes of activities for all species on the
Regulated Plant Index, including the clearing or removal of regulated
plants for agricultural, forestry, mining, construction (residential,
commercial, or infrastructure), and fire-control activities by a
private landowner or his or her agent. On the other hand, section (10)
of the statute provides for consultation similar to section 7 of the
Federal Act for listed species by requiring the Department of
Transportation to notify the FDACS and the Endangered Plant Advisory
Council of planned highway construction at the time bids are first
advertised, to facilitate evaluation of the project for listed plant
populations, and to ``provide for the appropriate disposal of such
plants'' (i.e., transplanting).
Local
In 1984, Section 24-49 of the Code of Miami-Dade County established
regulation of County-designated NFCs, which include both pine rocklands
and tropical hardwood hammocks. These regulations were placed on
specific properties throughout the county by an act of the Board of
County Commissioners in an effort to protect environmentally sensitive
forest lands. The Miami-Dade County Department of Regulatory and
Economic Resources has regulatory authority over NFCs and is charged
with enforcing regulations that provide partial protection on the Miami
Rock Ridge. Miami-Dade Code typically allows up to 20 percent of a pine
rockland designated as NFC to be developed, and requires that the
remaining 80 percent be placed under a perpetual covenant. In certain
circumstances, where the landowner can demonstrate that limiting
development to 20 percent does not allow for ``reasonable use'' of the
property, additional development may be approved. NFC landowners are
also required to obtain an NFC permit for any work, including removal
of nonnatives within the boundaries of the NFC on their property. The
NFC program is responsible for ensuring that NFC permits are issued in
accordance with the limitations and requirements of the code and that
appropriate NFC preserves are established and maintained in conjunction
with the issuance of an NFC permit. The NFC program currently regulates
[[Page 70298]]
approximately 600 pine rockland or pine rockland/hammock properties,
comprising approximately 1,200 ha (3,000 ac) of habitat (Joyner 2013a,
pers. comm.).
Although the NFC program is designed to protect rare and important
upland (non-wetlands) habitats in south Florida, this regulatory
strategy has limitations. For example, in certain circumstances where
landowners can demonstrate that limiting development to 20 percent does
not allow for ``reasonable use'' of the property, additional
development may be approved. Furthermore, Miami-Dade County Code
provides for up to 100 percent of the NFC to be developed on a parcel
in limited circumstances for parcels less than 2.02 ha (5 ac) in size
and requires coordination with the landowner only if the landowner
plans to develop property or perform work within the NFC designated
area. As such, the majority of the existing private forested NFC
parcels consists of isolated fragments, without management obligations
or preserve designation, as development has not been proposed at a
level that would trigger the NFC regulatory requirements. Often,
nonnative vegetation over time begins to dominate and degrade the
undeveloped and unmanaged NFC landscape until it no longer meets the
legal threshold of an NFC, which requires the land to be dominated by
native vegetation. When development of such degraded NFCs is proposed,
Miami-Dade County Code requires delisting of the degraded areas as part
of the development process. Property previously designated as NFC is
removed from the list even before development is initiated because of
the abundance of nonnative species, making it no longer considered to
be jurisdictional or subject to the NFC protection requirements of
Miami-Dade County Code (Grossenbacher 2013, pers. comm.).
Summary of Factor D
Currently, Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana are found on Federal, State, and County
lands; however, there is no regulatory mechanism in place that provides
substantive protection of actual habitat or of potentially suitable
habitat at this time. NPS regulations provide some protection at ENP
and BCNP sites, whichprotect the largest and best managed populations.
State regulations provide protection against trade, but allow private
landowners or their agents to clear or remove species on the Florida
Regulated Plant Index. State Park regulations provide protection for
plants within Florida State Parks. The NFC program in Miami is designed
to protect rare and important upland (non-wetlands) habitats in south
Florida; however, this regulatory strategy has several limitations (as
described above) that reduce its ability to protect S. reclinatum ssp.
austrofloridense, D. pauciflora, C. deltoidea ssp. pinetorum, and D.
carthagenensis var. floridana and their habitats.
Although most populations of Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana are afforded some
level of protection because they are on public conservation lands,
existing regulatory mechanisms have not led to a sufficient reduction
of threats posed to these plants by a wide array of sources (see
discussions under Factors A and E).
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Other natural or manmade factors affect Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana to varying degrees,
including the spread of nonnative invasive plants, potentially
incompatible management practices (such as mowing and herbicide use),
direct impacts to plants from recreation and other human activities,
small population size and isolation, climate change, and the related
risks from environmental stochasticity (extreme weather) on small
populations. Each of these threats and its specific effect on these
species are discussed in detail below.
Nonnative Plant Species
Nonnative invasive plants compete with native plants for space,
light, water, and nutrients, and make habitat conditions unsuitable for
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana, which prefer open conditions. Bradley and Gann (1999, pp.
13, 71-72) indicated that the control of nonnative plants is one of the
most important conservation actions for the four plants and a critical
part of habitat maintenance.
Nonnative plants have significantly affected pine rocklands, and
negatively impact all occurrences of Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana to some degree
(Bradley 2006, pp. 25-26; Bradley and Gann 1999, pp. 18-19; Bradley and
Saha 2009, p. 25; Bradley and van der Heiden 2013, pp. 12-16). As a
result of human activities, at least 277 taxa of nonnative plants have
invaded pine rocklands throughout south Florida (Service 1999, p. 3-
175). Schinus terebinthifolius (Brazilian pepper) and Neyraudia
neyraudiana (Burma reed) affect these species (Bradley and Gann 1999,
pp. 13, 72). Brazilian pepper, a nonnative tree, is the most widespread
and one of the most invasive species. It forms dense thickets of
tangled, woody stems that completely shade out and displace native
vegetation (Loflin 1991, p. 19; Langeland and Craddock Burks 1998, p.
54). Lygodium microphyllum (Old World climbing fern) is also a serious
threat throughout south Florida.
Nonnative plants in pine rocklands can also affect the
characteristics of a fire when it does occur. Historically, pine
rocklands had an open, low understory where natural fires remained
patchy with low temperature intensity. S. ssp. austrofloridense, D.
pauciflora, C. deltoidea ssp. pinetorum, and D. carthagenensis var.
floridana thrive under this fire regime. However, dense infestations of
Neyraudia neyraudiana and Schinus terebinthifolius cause higher fire
temperatures and longer burning periods.
These nonnative species occur throughout the ranges of the four
plants. In ENP and BCNP, invasives tend to be fewer due to the
insularity of these sites and the NPS's control programs. Nevertheless,
most areas require annual treatments to remove incipient invasions.
Management of nonnative invasive plants in pine rocklands in Miami-Dade
County is further complicated because the vast majority of pine
rocklands are small, fragmented areas bordered by urban development.
Areas near managed pine rockland that contain nonnative species can act
as a seed source of nonnatives allowing them to continue to invade the
surrounding pine rockland (Bradley and Gann 1999, p. 13).
Nonnative plant species are also a concern on private lands, where
often they are not controlled due to associated costs, lack of
interest, or lack of knowledge of detrimental impacts to the ecosystem.
Undiscovered populations of Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana on private lands
could certainly be at risk. Overall, active management is necessary to
control for nonnative
[[Page 70299]]
species and to protect unique and rare habitats where these plants
occur (Snyder et al. 1990, p. 273).
Mowing
While no studies have investigated the effect of mowing on
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, or Dalea carthagenensis var.
floridana, research has been conducted on the federally endangered
Linum carteri var. carteri (which also occurs in pine rocklands). The
study found significantly higher densities of plants at the mown sites
where competition with other plants is decreased (Maschinski et al.
2007, p. 56). However, plants growing on mown sites were shorter, which
may affect fruiting magnitude. While mowing did not usually kill adult
plants, it could delay reproduction if it occurred prior to plants
reaching reproductive status (Maschinski et al. 2007, pp. 56-57). If
such mowing occurs repeatedly, reproduction of those plants would be
entirely eliminated. Maschinski et al. (2008, p. 28) recommended
adjusting the timing of mowing to occur at least 3 weeks after
flowering is observed to allow a higher probability of adults setting
fruit prior to the mowing event. With flexibility and proper
instructions to land managers and ground crews, mowing practices could
be implemented in such a way as to scatter seeds and reduce competition
with little effect on population reproductive output for the year
(Maschinski et al. 2008, p. 28). The exact impacts of mowing also
depend on the timing of rainfall prior to and following mowing, and the
numbers of plants in the population that have reached a reproductive
state.
Recreation and Other Human Activities
Recreational use of off-road vehicles (ORV) is a threat to
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora, and
Dalea carthagenensis var. floridana occurrences within BCNP (K. Bradley
et al. 2013, p. 3). Operators frequently veer off established trails,
and plants can be harmed or destroyed (Bradley and Gann 1999, p. 43).
BCNP manages ORV access using a permit system, regulations, and
designated trails. However, there are over 1,000 miles of ORV trails in
BCNP, and only one enforcement officer (Pernas pers. comm., 2016),
making enforcement of designated ORV trails a challenge. Current aerial
imagery from the Lostman's Pine area of BCNP, where Digitaria
pauciflora occurs, shows a criss-cross pattern of multiple ORV trails
through the area. The Service is working with BCNP to determine the
extent to which ORVs are affecting all three species at this site,
particularly D. pauciflora, since it is one of only two sites where the
species is known to exist. Damage from ORV use has also been documented
for Dalea carthagenensis var. floridana within the Charles Deering
Estate (J. Possley, pers. comm. 2008, 2009).
Dalea carthagenensis var. floridana at the R. Hardy Matheson
Preserve is also impacted by illegal mountain biking (Bradley and Gann
1999, pp. 43-45). In the past, this pineland fragment was heavily used
by mountain bikers. In response Miami-Dade County has erected fencing
to protect this site, which appears to have reduced this threat
(Bradley and Gann 1999, p. 43).
Effects of Small Population Size and Isolation
Endemic species whose populations exhibit a high degree of
isolation are extremely susceptible to extinction from both random and
nonrandom catastrophic natural or human-caused events. Species that are
restricted to geographically limited areas are inherently more
vulnerable to extinction than widespread species because of the
increased risk of genetic bottlenecks, random demographic fluctuations,
effects of climate change, and localized catastrophes such as
hurricanes and disease outbreaks (Mangel and Tier 1994, p. 607; Pimm et
al. 1988, p. 757). These problems are further magnified when
populations are few and restricted to a very small geographic area, and
when the number of individuals is very small. Populations with these
characteristics face an increased likelihood of stochastic extinction
due to changes in demography, the environment, genetics, or other
factors (Gilpin and Soule 1986, pp. 24-34).
Small, isolated populations, such as those in fragmented habitat,
often exhibit reduced levels of genetic variability, although the
ultimate effect of these changes is dependent on a plant's specific
life history, reproductive system, and interaction with pollinators and
dispersal vectors (which may themselves be affected by fragmentation)
(Young et al. 1996, p. 413). While research results clearly indicate
that isolation/fragmentation has population genetic consequences for
plants, consequences are varied and for some species there may be a
``fragmentation threshold'' below which genetic variation is not lost
(Young et al. 1996, p. 416). No such studies have been conducted for
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana, so whether these plants exhibit such a threshold is not
known.
Reduced genetic variability generally diminishes a species'
capacity to adapt and respond to environmental changes, thereby
decreasing the probability of long-term persistence (e.g., Barrett and
Kohn 1991, p. 4; Newman and Pilson 1997, p. 361). Very small plant
populations may experience reduced reproductive vigor due to
ineffective pollination or inbreeding depression. Isolated individuals
have difficulty achieving natural pollen exchange, which limits the
production of viable seed. The problems associated with small
population size and vulnerability to random demographic fluctuations or
natural catastrophes are further magnified by synergistic (interaction
of two or more components) effects with other threats, such as those
discussed above (Factors A and C). Tables 1, 2, 3, and 4 above list the
population sizes and the geographic ranges for S. reclinatum ssp.
austrofloridense, D. pauciflora, C. deltoidea ssp. pinetorum, and D.
carthagenensis var. floridana. For example, table 2 lists Digitaria
pauciflora as having 2 extant populations (ENP and BCNP), one estimated
at 1,000-10,000 plants and the other with greater than 10,000 plants.
The Service does not consider these as small populations; however, a
large wildfire or severe flooding could be catastrophic. As shown in
2016, D. pauciflora was impacted by fire in ENP and flooding in ENP and
BCNP, proving that the small geographic extent of the existing
populations is not sufficient to eliminate the risk posed by large-
scale disturbances.
Effects of Climate Change
Climatic changes, including sea level rise (SLR), are major threats
to the flora of south Florida, including Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, or Dalea carthagenensis var. floridana. Our analyses under
the Act include consideration of ongoing and projected changes in
climate. With regard to our analysis for Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, or Dalea carthagenensis var. floridana, downscaled
projections suggest that SLR is the largest climate-driven challenge to
low-lying coastal areas in the subtropical ecoregion of southern
Florida (U.S. Climate Change Science Program (USCCSP) 2008, pp. 5-31,
5-32).
[[Page 70300]]
The long-term record at Key West shows that sea level rose on
average 0.229 cm (0.090 in) annually between 1913 and 2013 (NOAA 2013,
p. 1). This equates to approximately 22.9 cm (9.02 in) over the last
100 years. IPCC (2008, p. 28) emphasized it is very likely that the
average rate of SLR during the 21st century will exceed the historical
rate. Heat trapped by greenhouse gases causes atmospheric warming, but
the ocean is a vast heat sink where most of the increased heat energy
is stored. As the water increases in temperature, its volume expands.
Due to the thermal dynamic properties of water, as projected
temperatures increase, so does the volume of the ocean, and the rate of
expansion. As a result, most models show a dramatic increase in the
rate of SLR rise by mid-century. The IPCC Special Report on Emission
Scenarios (2000, entire) presented a range of scenarios based on the
computed amount of change in the climate system due to various
potential amounts of anthropogenic greenhouse gases and aerosols in
2100. Each scenario describes a future world with varying levels of
atmospheric pollution leading to corresponding levels of global warming
and corresponding levels of SLR. The IPCC Synthesis Report (2007,
entire) provided an integrated view of climate change and presented
updated projections of future climate change and related impacts under
different scenarios.
Subsequent to the 2007 IPCC Report, the scientific community has
continued to model SLR. Recent peer-reviewed publications indicate a
movement toward increased acceleration of SLR. Observed SLR rates are
already trending along the higher end of the 2007 IPCC estimates, and
it is now widely held that SLR will exceed the levels projected by the
IPCC (Rahmstorf et al. 2012, p. 1; Grinsted et al. 2010, p. 470). Taken
together, these studies support the use of higher end estimates now
prevalent in the scientific literature. Recent studies have estimated
global mean SLR of 1-2 m (3.3-6.6 ft) by 2100 as follows: 0.75-1.90 m
(2.5-6.2 ft; Vermeer and Rahmstorf 2009, p. 21530), 0.8-2.0 m (2.6-6.6
ft; Pfeffer et al. 2008, p. 1342), 0.9-1.3 m (3.0-4.3 ft; Grinsted et
al. 2010, pp. 469-470), 0.6-1.6 m (2.0-5.2 ft; Jevrejeva et al. 2010,
p. 4), and 0.5-1.40 m (1.6-4.6 ft; National Resource Council 2012, p.
2).
Other processes expected to be affected by projected warming
include temperatures, rainfall (amount, seasonal timing, and
distribution), and storms (frequency and intensity) (discussed more
specifically under Environmental Stochasticity, below). The
Massachusetts Institute of Technology (MIT) modeled several scenarios
combining various levels of SLR, temperature change, and precipitation
differences with human population growth, policy assumptions, and
conservation funding changes (see Alternative Future Landscape Models,
below). All of the scenarios, from small climate change shifts to major
changes, indicate significant effects on coastal Miami-Dade County.
Decades prior to inundation, pine rocklands are likely to undergo
vegetation shifts related to climate change, triggered by changes to
hydrology (wetter), salinity (higher) and increasing vulnerability to
storm surge (pulse events causing massive erosion and salinization of
soils) (Saha et al.2011, p. 82). Hydrology has a strong influence on
plant distribution in these and other coastal areas (IPCC 2008, p. 57).
Such communities typically grade from saltwater to brackish to
freshwater species. From the 1930s to 1950s, increased salinity of
coastal waters contributed to the decline of cabbage palm forests in
southwest Florida (Williams et al. 1999, pp. 2056-2059), expansion of
mangroves into adjacent marshes in the Everglades (Ross et al. 2000,
pp. 101, 111), and loss of pine rockland in the Keys (Ross et al. 1994,
pp. 144, 151-155). In one Florida Keys pine rockland with an average
elevation of 0.89 m (2.9 ft), Ross et al. (1994, pp. 149-152) observed
an approximately 65 percent reduction in an area occupied by South
Florida slash pine over a 70-year period, with pine mortality and
subsequent increased proportions of halophytic (salt-loving) plants
occurring earlier at the lower elevations. During this same time span,
local sea level had risen by 15 cm (6.0 in), and Ross et al. (1994, p.
152) found evidence of groundwater and soil water salinization.
Extrapolating this situation to pine rocklands on the mainland is
not straightforward, but indications are that similar changes to
species composition could arise if current projections of SLR occur and
freshwater inputs are not sufficient to prevent salinization.
Furthermore, Ross et al. (2009, pp. 471-478) suggested that
interactions between SLR and pulse disturbances (e.g., storm surges)
can cause vegetation to change sooner than projected based on sea level
alone. Alexander (1953, pp. 133-138) attributed the demise of pinelands
on northern Key Largo to salinization of the groundwater in response to
SLR. Patterns of human development will also likely be significant
factors influencing whether natural communities can move and persist
(IPCC 2008, p. 57; USCCSP 2008, p. 7-6).
The Science and Technology Committee of the Miami-Dade County
Climate Change Task Force (Wanless et al. 2008, p. 1) recognized that
significant SLR is a very real threat to the near future for Miami-Dade
County. In a January 2008 statement, the committee warned that sea
level is expected to rise at least 0.9-1.5 m (3-5 ft) within this
century (Wanless et al. 2008, p. 3). With a 0.9-1.2 m (3-4 ft) rise in
sea level (above baseline) in Miami-Dade County, spring high tides
would be at about 6 to 7 ft; freshwater resources would be gone; the
Everglades would be inundated on the west side of Miami-Dade County;
the barrier islands would be largely inundated; storm surges would be
devastating; landfill sites would be exposed to erosion contaminating
marine and coastal environments. Freshwater and coastal mangrove
wetlands will not keep up with or offset SLR of 2 ft per century or
greater. With a 5-ft rise (spring tides at nearly +8 ft), the land area
of Miami-Dade County will be extremely diminished (Wanless et al. 2008,
pp. 3-4).
Drier conditions and increased variability in precipitation
associated with climate change are expected to hamper successful
regeneration of forests and cause shifts in vegetation types through
time (Wear and Greis 2012, p. 39). Although this issue has not been
well studied, existing pine rocklands have probably been affected by
reductions in the mean water table. Climate changes are also forecasted
to extend fire seasons and the frequency of large fire events
throughout the Coastal Plain (Wear and Greis 2012, p. 43). These
factors will likely cause an increase in wildfires and exacerbate
complications related to prescribed burning (i.e., less predictability
related to rainfall, fuel moisture, and winds) or other management
needed to restore and maintain habitat for the four plants. While
restoring fire to pine rocklands is essential to the long-term
viability of Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana populations, increases in the scale,
frequency, or severity of wildfires could have negative effects on
these plants considering their general vulnerability due to small
population size, restricted range, few occurrences, and relative
isolation. Big, hot wildfires can destroy essential habitat features of
pine rockland habitat. In addition, hot burns with long residence times
(which are more likely under wildfire conditions)
[[Page 70301]]
can also sterilize the soil seed bank and cause a demographic crash in
plant populations.
Alternative Future Landscape Models
To accommodate the large uncertainty in SLR projections,
researchers must estimate effects from a range of scenarios. Various
model scenarios developed at MIT and GeoAdaptive Inc. have projected
possible trajectories of future transformation of the south Florida
landscape by 2060 based upon four main drivers: climate change, shifts
in planning approaches and regulations, human population change, and
variations in financial resources for conservation. The scenarios do
not account for temperature, precipitation, or species habitat shifts
due to climate change, and no storm surge effects are considered. The
current MIT scenarios range from an SLR of 0.09-1.0 m (0.3-3.3 ft) by
2060 (Vargas-Moreno and Flaxman 2010, pp. 1-6).
Based on the most recent estimates of anticipated SLR, the upward
trend in recent projections toward the higher range of earlier SLR
estimates (discussed above), and the data available to us at this time,
we evaluated potential effects of SLR using the current ``high'' range
MIT scenario as well as comparing elevations of remaining pine rockland
fragments and extant and historical occurrences of Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana. The
``high'' range (or ``worst case'') MIT scenario assumes high SLR (1 m
(3.3 ft) by 2060), low financial resources, a ``business as usual''
approach to planning, and a doubling of human population.
The rate of SLR will increase as time passes. This is due to
atmospheric and ocean warming and the thermal expansion properties of
water. In SLR models the rate of sea level rise is projected to
increase dramatically around mid-century.
Most populations of Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, and Chamaesyce deltoidea ssp. pinetorum occur at
elevations less than 2 m (6.6 ft) above sea level, making these species
highly susceptible to increased storm surges and related impacts
associated with SLR. Areas of the Miami Rock Ridge in Miami-Dade County
(located to the east of ENP and BCNP) are higher elevation (maximum of
7 m [22 ft] above sea level) than those in BCNP (FNAI 2010, p. 62).
However, plant communities along South Florida's low-lying coasts are
organized along a mild gradient in elevation, transitioning from
mangroves at sea level to salinity-intolerant interior habitats,
including pine rocklands and hardwood hammocks within an elevation
change of 2 m (6.5 ft) above sea level. As a result, a rise of 1 m (3.3
ft) in sea level is expected to render coastal systems susceptible to
increased erosion and cause these areas to transition from upland
forest habitats to saline wetland habitats.
Prior to the onset of sustained inundation, there will be
irreversible changes in vegetation composition within these habitats.
Shifts in habitat toward hydric and saline ecosystems may occur decades
in advance of full inundation, rendering the habitat unsuitable for
salt-intolerant species including S. reclinatum ssp. austrofloridense,
D. pauciflora, C. deltoidea ssp. pinetorum, and D. carthagenensis var.
floridana (Saha et al.2011, p. 82). As interior habitats become more
saline there will be a reduction in freshwater inflows to the estuarine
portions of ENP and BCNP, accelerating losses in salinity-intolerant
coastal plant communities (Saha et al. 2011, p. 105), such as S.
reclinatum ssp. austrofloridense, D. pauciflora, C. deltoidea ssp.
pinetorum, or D. carthagenensis var. floridana.
Actual impacts may be greater or less than anticipated based upon
the high variability of factors involved (e.g., SLR, human population
growth) and assumptions made, but based on the current ``high'' range
MIT scenario, pine rocklands, marl prairies and associated habitats
along the coast in central and southern Miami-Dade County would become
inundated. The ``new'' sea level would occur at the southern end of the
Miami Rock Ridge (the eastern edge of the Everglades). However, in
decades prior to the fully anticipated sea level rise, changes in the
water table and increased soil salinity from partial inundation and
storm surge will result in vegetation shifts within BCNP, ENP, and
conservation lands on the southern Miami Rock Ridge. Inundation will
result in pine rocklands gaining increased marl prairie
characteristics. Marl prairies, in turn, will transition to sawgrass or
more hydric conditions, due to increased inundation.
As a result, species such as Digitaria pauciflora and Sideroxylon
reclinatum ssp. austrofloridense, which are most abundant within the
ecotone between pine rocklands and marl prairies, will gradually
decline as these habitat types merge and eventually disappear. Under
this scenario, by 2060, all extant populations of Digitaria pauciflora,
as well as the largest populations of Sideroxylon reclinatum ssp.
austrofloridense and Dalea carthagenensis var. floridana, would likely
be lost or significantly impacted by shifts in vegetation communities.
Populations of Sideroxylon reclinatum ssp. austrofloridense, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana would
likely remain only at the highest elevations along the Miami Rock
Ridge. In addition, many existing pine rockland fragments are projected
to be developed for housing as the human population grows and adjusts
to changing sea levels under this scenario.
Further or Additional Impacts Expected Beyond 2060
Further direct losses to extant populations of all four plants are
expected due to habitat loss and modification from SLR through 2100. We
analyzed existing sites that support populations of the four plants
using the National Oceanic and Atmospheric Administration (NOAA) Sea
Level Rise and Coastal Impacts viewer. Below we discuss general
implications of sea level rise within the range of projections
discussed above on the current distribution of these species. The NOAA
tool uses 1-foot increments. Our analysis is based on 0.91 m (3 ft) and
1.8 m (6 ft) of SLR.
Based on a higher SLR of 1.8 m (6 ft), as projected by NOAA, much
larger portions of urban Miami-Dade County, including conservation
areas, such as Navy Wells Pineland Preserve, will be inundated by 2100.
Under such a 1.8-meter SLR projection, both extant populations of D.
pauciflora in ENP and BCNP would be almost entirely inundated by 2100,
and the species will be extinct. Several extant occurrences of
Sideroxylon reclinatum ssp. austrofloridense, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana would also be lost.
The western part of urban Miami-Dade County would also be inundated
(barring creation of sea walls or other barriers), creating a virtual
island of the Miami Rock Ridge.
Following a 1.8-m (6-ft) rise in sea level, approximately 75
percent of presently extant pine rocklands on the Miami Rock Ridge
would still remain above sea level. However, an unknown percentage of
remaining pine rockland fragments would be negatively impacted by water
table and soil salinization, which would be further exacerbated due to
isolation from mainland fresh water flows.
Projections of SLR above 1.8 m (6 ft) indicate that very little
pine rockland would remain, with the vast majority either being
inundated or experiencing
[[Page 70302]]
vegetation shifts, resulting in the extirpation of all known
populations of Digitaria pauciflora, Sideroxylon reclinatum ssp.
austrofloridense, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana.
Environmental Stochasticity
Endemic species whose populations exhibit a high degree of
isolation and narrow geographic distribution, such as Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana, are
extremely susceptible to extinction from both random and nonrandom
catastrophic natural or human-caused events. Small populations of
species, without positive growth rates, are considered to have a high
extinction risk from site-specific demographic and environmental
stochasticity (Lande 1993, pp. 911-927).
The climate of southern Florida is driven by a combination of
local, regional, and global events, regimes, and oscillations. There
are three main ``seasons'': (1) the wet season, which is hot, rainy,
and humid from June through October; (2) the official hurricane season
that extends one month beyond the wet season (June 1 through November
30), with peak season being August and September; and (3) the dry
season, which is drier and cooler, from November through May. In the
dry season, periodic surges of cool and dry continental air masses
influence the weather with short-duration rain events followed by long
periods of dry weather.
Florida is considered the most vulnerable State in the United
States to hurricanes and tropical storms (Florida Climate Center,
http://coaps.fsu.edu/climate_center). Based on data gathered from 1856
to 2008, Klotzbach and Gray (2009, p. 28) calculated the climatological
probabilities for each State being impacted by a hurricane or major
hurricane in all years over the 152-year timespan. Of the coastal
States analyzed, Florida had the highest climatological probabilities,
with a 51 percent probability of a hurricane (Category 1 or 2) and a 21
percent probability of a major hurricane (Category 3 or higher). From
1856 to 2015, Florida actually experienced 109 hurricanes and 36 major
hurricanes. While not every hurricane will pass over south Florida,
given the low population sizes and restricted ranges of Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana
within locations prone to storm influences, these species are at
substantial risk from hurricanes, storm surges, and other extreme
weather. Depending on the location and intensity of a hurricane or
other severe weather event, it is possible that the plants could become
extirpated or extinct.
Hurricanes, storm surge, and extreme high tide events are natural
events that can negatively impact these four plants. Hurricanes and
tropical storms can modify habitat (e.g., through storm surge) and have
the potential to destroy entire populations, physically washing them
away or leaving soil too saline for them to persist. Climate change may
lead to increased frequency and duration of severe storms (Golladay et
al. 2004, p. 504; McLaughlin et al. 2002, p. 6074; Cook et al. 2004, p.
1015). Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, or Dalea
carthagenensis var. floridana experienced these disturbances
historically, but had the benefit of more abundant and contiguous
habitat to buffer them from extirpations. With most of the historical
habitat having been destroyed or modified, the few remaining
populations of these species could face local extirpations due to
stochastic events.
Other processes to be affected by climate change, related to
environmental stochasticity, include temperatures, rainfall (amount,
seasonal timing, and distribution), and storms (frequency and
intensity). Temperatures are projected to rise from 2-5 [deg]C (3.6-9
[deg]F) for North America by the end of this century (IPCC 2007, pp. 7-
9, 13). These factors will likely cause an increase in wildfires and
exacerbate complications related to prescribed burning or other
management needed to restore and maintain habitat for the four plants.
Based upon modeling, Atlantic hurricane and tropical storm frequencies
are expected to decrease (Knutson et al. 2008, pp. 1-21). By 2100,
there should be a 10-30 percent decrease in hurricane frequency.
Hurricane frequency is expected to drop due to more wind shear impeding
initial hurricane development. However, hurricane winds are expected to
increase by 5-10 percent, which will increase storm surge heights. This
is due to more hurricane energy being available for intense hurricanes.
In addition to climate change, weather variables are extremely
influenced by other natural cycles, such as El Ni[ntilde]o Southern
Oscillation with a frequency of every 4-7 years, solar cycle (every 11
years), and the Atlantic Multi-decadal Oscillation. All of these cycles
influence changes in Floridian weather. The exact magnitude, direction,
and distribution of all of these changes at the regional level are
difficult to project.
Freezing Temperatures
Occasional freezing temperatures that occur in south Florida pose a
risk to Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, or Dalea
carthagenensis var. floridana, causing damage or death to individual
plants. Under normal circumstances, occasional freezing temperatures
would not result in a significant impact to populations of these
plants; however, the small size of some populations means the loss from
freezing events of even a few individuals can reduce the viability of
the population.
Hydrology and Everglades Restoration
Hydrology is a key ecosystem component that affects rare plant
distributions and their viability (Gann et al. 2006, p. 4).
Historically, sheet flow from Shark River Slough and Taylor Slough did
not reach the upland portions of Long Pine Key, but during the wet
season increased surface water flow in sloughs generated a rise in
ground water across the region (Gann et al. 2006, p. 4). Water flow
through Long Pine Key was originally concentrated in marl prairies,
traversing in a north-south direction; however, construction of the
main ENP road dissected Long Pine Key in an east-west direction,
thereby impeding sheet flow across this area (Gann et al. 2006, p. 4).
Water was either impounded to the north of the main ENP road or
diverted around the southern portion of Long Pine Key through Taylor
Slough and Shark River Slough (Gann et al. 2006, p. 4). As artificial
drainage became more widespread, however, regional groundwater supplies
declined.
While projects designed to restore the historical hydrology of the
Everglades and other natural systems in southern Florida, including ENP
and BCNP (collectively known as the Comprehensive Everglades
Restoration Plan (CERP)), are beneficial to the Everglades ecosystem,
some may produce collateral impacts to extant pine rockland, marl
prairies, and associated habitats within the region through inundation
or increased hydroperiods. The effects of changes in regional hydrology
through restoration may have impacts on the four plant species and
their habitats. Sadle (2012, pers. comm.) suggested various CERP
projects (such as C-111 spreader canal; L-31N seepage barrier),
specifically the operation of pumps and associated detention areas
along the ENP
[[Page 70303]]
boundary, may influence (through excessive water discharges) select
portions of eastern Long Pine Key. Increased and longer-duration
hydroperiods within the pine rockland and marl prairie habitats where
these species occur may lead to a reduction in the amount of suitable
habitat, a potential reduction in the area occupied and a reduction in
the number of individuals found in ENP and BCNP. It is unclear to what
extent this may occur, if at all. In an effort to establish a baseline
assessment of future hydrologic modifications, long-term monitoring
transects and plots for Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, and Chamaesyce deltoidea ssp. pinetorum were
established in Long Pine Key between 2003 and 2008 (Gann 2015, p. 169).
Conservation Efforts To Reduce Other Natural or Manmade Factors
Affecting Continued Existence
NPS, the Service, Miami-Dade County, and the State of Florida have
ongoing nonnative plant management programs to reduce threats on public
lands, as funding and resources allow. In Miami-Dade County, nonnative,
invasive plant management is very active, with a goal to treat all
publicly owned properties at least once a year and more often in many
cases. IRC and FTBG conduct research and monitoring in various natural
areas within Miami-Dade County and the Florida Keys for various
endangered plant species and nonnative, invasive species. For the four
plants, monitoring detects declines that lead to small population size,
changes in habitat due to SLR, and declines due to stochastic events.
For nonnatives, monitoring is an integral part of efforts to detect and
control invasive plant and animal species.
Summary of Factor E
We have discussed threats from other natural or manmade factors
including: nonnative invasive plants, management practices (such as
mowing and herbicide use), recreation (including ORV use), effects from
small population size and isolation, limited geographic range, and
stochastic events including hurricanes, storm surges, and wildfires.
Additionally, these plants are particularly vulnerable to the effects
of climate change, including SLR, as changes in the water table,
increased soil salinity from partial inundation, and storm surge will
likely result in vegetation shifts in the decades prior to the fully
anticipated sea level rise. Some of these threats (e.g., nonnative
species) may be reduced on public lands due to active programs by
Federal, State, and County land managers. Many of the remaining
populations of these plants are small and geographically isolated, and
genetic variability is likely low, increasing the inherent risk due to
overall low resilience of these plants. The threats act together to
impact populations of Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, or Dalea
carthagenensis var. floridana.
Cumulative Effects of Threats
When two or more threats affect populations of Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana, the
effects of those threats could interact or become compounded, producing
a cumulative adverse effect that is greater than the impact of either
threat alone. The most obvious cases in which cumulative adverse
effects would be significant are those in which small populations
(Factor E) are affected by threats that result in destruction or
modification of habitat (Factor A), ORV damage (Factor E), or
stochastic events, such as hurricanes, storm surges, wildfires (Factor
E). The limited distributions and/or small population sizes of many
populations of S. reclinatum ssp. austrofloridense, D. pauciflora, C.
deltoidea ssp. pinetorum, and D. carthagenensis var. floridana make
them extremely susceptible to the detrimental effects of further
habitat modification, degradation, and loss, as well as other
anthropogenic threats. Mechanisms leading to the decline of S.
reclinatum ssp. austrofloridense, D. pauciflora, C. deltoidea ssp.
pinetorum, and D. carthagenensis var. floridana, as discussed above,
range from local (e.g., agriculture) to regional (e.g., development,
fragmentation, nonnative species) to global influences (e.g., effects
of climate change, SLR). The synergistic effects of threats, such as
impacts from hurricanes on a species with a limited distribution and
small populations, make it difficult to predict population viability.
While these stressors may act in isolation, it is more probable that
many stressors are acting simultaneously (or in combination) on
populations of S. reclinatum ssp. austrofloridense, D. pauciflora, C.
deltoidea ssp. pinetorum, and D. carthagenensis var. floridana, making
them more vulnerable.
Proposed Determination
We have carefully assessed the best scientific and commercial data
available regarding the past, present, and future threats to
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana.
Sideroxylon reclinatum ssp. austrofloridense
Nine of 11 extant populations are located on publicly owned
conservation lands. This includes 10,000-100,000 plants at ENP, and a
small population at BCNP, where prescribed fire implementation has
improved, and nonnative plant control efforts are adequate to
beneficially manage habitat for native species. In contrast, in the
scattered small populations on Miami-Dade habitat fragments,
representing half of the species' historical range, habitat management
currently is not adequate due to the inability to conduct prescribed
fire. Increasing temperatures and changes in precipitation patterns
associated with climate change will likely cause an increase in
wildfires and exacerbate complications related to prescribed burning or
other management needed to restore and maintain habitat for the
species. In the current, fragmented landscape, dispersal and genetic
exchange for any of these smaller Miami-Dade populations is unlikely,
because they exist in isolated habitat patches surrounded by miles of
unsuitable habitat (agriculture and urban development). Two privately
owned sites in Miami supporting extant populations are vulnerable to
development. The largest populations (ENP and BCNP) are vulnerable to
hydrologic changes related to Everglades restoration projects and SLR.
SLR projections suggest future inundation and modification to the
majority of Sideroxylon reclinatum ssp. austrofloridense habitat in ENP
and BCNP by 2060. Decades prior to inundation, however, pine rocklands,
marl prairies, and associated habitats within ENP and BCNP will undergo
habitat transitions toward wetter, salt-tolerant plant communities,
hydrological changes, and increasing vulnerability to storm surge.
Although the effects of SLR within urban Miami-Dade fragments may be
less severe, these pine rocklands will, at a minimum, experience
partial inundations and vegetation shifts. In addition, many existing
Miami-Dade pine rockland fragments are projected to be developed for
housing as the human population grows and adjusts to changing sea
levels under this scenario.
Digitaria pauciflora
Only two of five historical Digitaria pauciflora locations are
extant. They are located in BCNP (>10,000 plants) and
[[Page 70304]]
ENP (1,000-10,000 plants) on publicly owned conservation lands where
habitat management (prescribed fire and nonnative plant control) is
ongoing and includes addressing a backlog of long-unburned sites that
could result in larger wildfires if burns are not implemented. In
addition, although we do not have evidence of direct impacts, given the
mapped overlap of ORV trails with Digitaria pauciflora locations, ORV
use in BCNP has likely resulted in damage to Digitaria pauciflora
plants and habitat. The scattered small populations that once occurred
in Miami-Dade habitat fragments, representing the remainder of the
species' historical range, are extirpated, and current habitat
management does not allow for prescribed fire to be conducted on a
consistent basis. Increasing temperatures and changes in precipitation
patterns associated with climate change will likely cause an increase
in wildfires and exacerbate complications related to prescribed burning
or other management needed to restore and maintain habitat for the
species.
Digitaria pauciflora previously occurred within the Richmond Pine
Rocklands, an area that retains the largest remaining contiguous
privately and publicly owned pine rocklands in Miami-Dade County,
outside of ENP. In terms of restoring the species' historical range,
the Richmond Pine Rocklands would serve as one of the most important
sites in Miami-Dade County for recovery efforts (i.e., reintroduction).
The largest populations (ENP and BCNP) are vulnerable to hydrological
changes related to Everglades restoration projects and SLR.
SLR projections suggest future partial inundation and modification
to the majority of D. pauciflora habitat by 2060. Decades prior to
inundation, however, pine rocklands, marl prairies, and associated
habitats within ENP and BCNP will undergo habitat transitions toward
wetter, salt-tolerant plant communities, hydrological changes, and
increase in vulnerability to storm surge. Although the effects of SLR
within urban Miami-Dade fragments may be less severe, these pine
rocklands will, at a minimum, experience partial inundations and
vegetation shifts. In addition, many existing Miami-Dade pine rockland
fragments are projected to be developed for housing as the human
population grows and adjusts to changing sea levels under this
scenario.
Chamaesyce deltoidea ssp. pinetorum
Eleven of 20 extant populations are located on publicly owned
conservation lands. This includes 10,000-100,000 plants at ENP and
1,000 plants at Navy Wells pineland, where habitat management
(prescribed fire and nonnative plant control) is ongoing, and includes
addressing a backlog of long-unburned sites that could result in larger
wildfires if burns are not implemented. In contrast, in the scattered
small populations on Miami-Dade habitat fragments, representing half of
the species' historical range, current habitat management does not
allow for prescribed fire to be conducted on a consistent basis.
Increasing temperatures and changes in precipitation patterns
associated with climate change will likely cause an increase in
wildfires and exacerbate complications related to prescribed burning or
other management needed to restore and maintain habitat for the
species. In the current, fragmented landscape, dispersal and genetic
exchange for any of these smaller Miami-Dade populations is unlikely,
because they exist in isolated habitat patches surrounded by miles of
unsuitable habitat (agriculture and urban development). Eight privately
owned sites in Miami supporting extant populations are vulnerable to
development, two of which support 1,000-10,000 plants each. The largest
population (Long Pine Key, ENP) is vulnerable to hydrological changes
related to Everglades restoration projects and SLR.
SLR projections suggest future inundation and modification to the
majority of Chamaesyce deltoidea spp. pinetorum habitat by 2060.
Decades prior to inundation, however, pine rocklands, marl prairies,
and associated habitats within ENP and BCNP will undergo habitat
transitions toward wetter, salt-tolerant plant communities,
hydrological changes, and increasing vulnerability to storm surge.
Although the effects of SLR within urban Miami-Dade fragments may be
less severe, these pine rocklands will, at a minimum, experience
partial inundations and vegetation shifts. In addition, many existing
Miami-Dade pine rockland fragments are projected to be developed for
housing as the human population grows and adjusts to changing sea
levels under this scenario.
Dalea carthagenensis var. floridana
Six of 9 extant populations are located on publicly owned
conservation lands. This total includes 253 plants at BCNP (Monroe
County), where prescribed fire and nonnative plant control efforts are
adequate to beneficially manage habitat for native species. The two
other largest populations occur in Miami-Dade County and consist of 347
plants at Charles Deering Estate, and 307 plants at R. Hardy Matheson
Preserve, where current habitat management does not allow for
prescribed fire to be conducted on a consistent basis. Higher
temperatures and changes in precipitation patterns associated with
climate change will likely cause an increase in wildfires and
exacerbate complications related to prescribed burning or other
management needed to restore and maintain habitat for the species. In
the current, fragmented landscape, dispersal and genetic exchange
between Miami-Dade populations is unlikely, because they exist in
isolated habitat patches surrounded by miles of unsuitable habitat
(agriculture and urban development). Three privately owned sites in
Miami supporting extant populations are vulnerable to development, two
of which support 17 and 21 plants each. The population within BCNP is
vulnerable to hydrological changes related to Everglades restoration
projects and SLR.
Numerous populations of all plants have been extirpated from these
species' historical ranges, and the primary threats of habitat
destruction and modification resulting from human population growth and
development, agricultural conversion, and inadequate fire management
(Factor A); competition from nonnative, invasive species (Factor E);
changes in climatic conditions, including SLR and changes in hydrology
(Factor E); and natural stochastic events, including hurricanes, storm
surges, and wildfires (Factor E) are threats for the existing
populations. Existing regulatory mechanisms have not reduced or removed
threats impacting the four plants from the other factors (see Factor D
discussion). These threats are ongoing, rangewide, and expected to
continue in the future. A significant percentage of populations of the
four plants are relatively small and isolated from one another, and
their ability to recolonize suitable habitat is unlikely without human
intervention, if at all. The threats have had and will continue to have
substantial adverse effects on Sideroxlyon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana and their habitats.
Although attempts are ongoing to alleviate or minimize some of these
threats at certain locations, all populations appear to be impacted by
one or more threats.
The Act defines an endangered species as ``any species which is in
danger of extinction throughout all or a significant portion of its
range'' and a threatened species as ``any species
[[Page 70305]]
which is likely to become an endangered species within the foreseeable
future throughout all or a significant portion of its range.'' We find
that Dalea carthagenensis var. floridana is presently in danger of
extinction throughout its entire range due to the immediacy and
severity of threats currently impacting the species. The risk of
extinction is high because there are few (9) extant populations and the
majority of the populations are small and isolated, and have limited to
no potential for recolonization. Therefore, on the basis of the best
available scientific and commercial information, we propose to list
Dalea carthagenensis var. floridana as an endangered species in
accordance with sections 3(6) and 4(a)(1) of the Act. We find that a
threatened species status is not appropriate for this species because
of the contracted range and small population size of Dalea
carthagenensis var. floridana and because of the current magnitude and
severity of the threats on the plant. Because the species is already in
danger of extinction throughout its range, a threatened species status
is not appropriate.
Sideroxlyon reclinatum ssp. austrofloridense, Digitaria pauciflora,
and Chamaesyce deltoidea ssp. pinetorum face threats similar to Dalea
carthagenensis var. floridana. However, we find that endangered species
status is not appropriate for these three species. While we have
evidence of threats under Factors A and E affecting the species, large
populations of these three species are protected and actively managed
at ENP and BCNP (Sideroxylon reclinatum ssp. austrofloridense, ENP
(10,000-100,000 plants); Digitaria pauciflora, BCNP (>10,000 plants),
and ENP (1,000-10,000 plants); and Chamaesyce deltoidea ssp. pinetorum
ENP (10,000-100,000 plants)). Short- and medium-term threats to these
three species in these protected areas are being addressed. On the
other hand, SLR is projected to have profound negative effects on the
habitat of these plants in the foreseeable future. Therefore, based on
the best available information, we find that Sideroxlyon reclinatum
ssp. austrofloridense, Digitaria pauciflora, and Chamaesyce deltoidea
ssp. pinetorum are likely to become endangered species within the
foreseeable future throughout all or a significant portion of its
range, and we propose to list these species as threatened species in
accordance with sections 3(20) and 4(a)(1) of the Act.
Significant Portion of the Range
Because we have determined that we are proposing to list
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora, and
Chamaesyce deltoidea ssp. pinetorum as threatened species and Dalea
carthagenensis var. floridana as an endangered species throughout all
of their ranges, no portion of their ranges can be ``significant'' for
purposes of the definitions of ``endangered species'' and ``threatened
species.'' See the Service's SPR Policy (79 FR 37578, July 1, 2014).
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, Tribal, and local agencies, private
organizations, and individuals. The Act encourages cooperation with the
States and other countries and calls for recovery actions to be carried
out for 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 calls for 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 also identifies
recovery criteria for review of when a species may be ready for
downlisting or delisting, 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. If these
species are listed, a 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 South Florida Ecological Service
Field 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, Tribes, 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 private, State, and Tribal 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 of Florida would be
eligible for Federal funds to implement management actions that promote
the protection or recovery of the four plants. Information on our grant
programs that are available to aid species recovery can be found at:
http://www.fws.gov/grants.
Although Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana 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 these species. Additionally, we
invite you to submit any new information on these plants 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
[[Page 70306]]
this interagency cooperation provision of the Act are codified at 50
CFR part 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.
Federal agency actions within these species' habitat that may
require conference or consultation or both as described in the
preceding paragraph and include management and any other landscape-
altering activities on Federal lands administered by the U.S. Fish and
Wildlife Service, National Park Service, and Department of Defense;
issuance of section 404 Clean Water Act permits by the Army Corps of
Engineers; construction and management of gas pipeline and power line
rights-of-way by the Federal Energy Regulatory Commission; construction
and maintenance of roads or highways by the Federal Highway
Administration; and disaster relief efforts conducted by the Federal
Emergency Management Agency.
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, the prohibitions outlined at 50
CFR 17.71 include all of the provisions in 50 CFR 17.61 that apply to
endangered plants, with one exception: seeds of cultivated specimens of
species treated as threatened shall be exempt from all 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.
Preservation of native flora of Florida (Florida Statutes 581.185)
sections (3)(a) and (b) provide limited protection to species listed in
the State of Florida Regulated Plant Index including Sideroxylon
reclinatum ssp. austrofloridense, Digitaria pauciflora, Chamaesyce
deltoidea ssp. pinetorum, and Dalea carthagenensis var. floridana as
described under Factor D, The Inadequacy of Existing Regulatory
Mechanisms. Federal listing increases protection for these plants by
making violations of section 3 of the Florida Statute punishable as a
Federal offense under section 9 of the Act. This provision provides
increased protection from unauthorized collecting and vandalism for the
plants on State and private lands, where they might not otherwise be
protected by the Act, and increases the severity of the penalty for
unauthorized collection, vandalism, or trade in these plants.
The Service acknowledges that it cannot fully address some of the
natural threats facing Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana (e.g., hurricanes, storm surge) or even
some of the other significant, long-term threats (e.g., climatic
changes, SLR). However, through listing, we provide protection to the
known populations and any new population of these plants that may be
discovered (see discussion below). With listing, we can also influence
Federal actions that may potentially impact this plant (see discussion
below); this protection is especially valuable if these plants are
found at additional locations.
We may issue permits to carry out otherwise prohibited activities
involving endangered plants under certain circumstances. Regulations
governing permits are codified at 50 CFR 17.62 and 17.72. With regard
to endangered plants, the Service may issue a permit authorizing any
activity otherwise prohibited by 50 CFR 17.61 and 17.72 for scientific
purposes or for enhancing the propagation or survival of endangered
plants.
It is our policy, as published in the Federal Register on July 1,
1994 (59 FR 34272), 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. Based on the best available information, the
following actions are unlikely to result in a violation of section 9,
if these activities are carried out in accordance with existing
regulations and permit requirements; this list is not comprehensive:
(1) Import any such species into, or export any such species from,
the United States;
(2) Remove and reduce to possession any such species from areas
under Federal jurisdiction; maliciously damage or destroy any such
species on any such area; or remove, cut, dig up, or damage or destroy
any such species on any other area in knowing violation of any law or
regulation of any State or in the course of any violation of a State
criminal trespass law;
(3) Deliver, receive, carry, transport, or ship in interstate or
foreign commerce, by any means whatsoever and in the course of a
commercial activity, any such species;
(4) Sell or offer for sale in interstate or foreign commerce any
such species;
(5) Introduce any nonnative wildlife or plant species to the State
of Florida that competes with or preys upon Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana;
(6) Release any unauthorized biological control agents that attack
any life stage of Sideroxylon reclinatum ssp. austrofloridense,
Digitaria pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana; or
(7) Engage in unauthorized manipulation or modification of the
habitat of Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum, and Dalea
carthagenensis var. floridana on Federal lands.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Field
Supervisor of the Service's South Florida Ecological Services Office
(see FOR FURTHER INFORMATION CONTACT). Requests for copies of
regulations regarding listed species and inquiries about prohibitions
and permits should be addressed to the U.S. Fish and Wildlife Service,
Ecological Services Division, Endangered Species Permits, 1875 Century
Boulevard, Atlanta, GA 30345 (Phone 404-679-7140; Fax 404-679-7081).
If Sideroxylon reclinatum ssp. austrofloridense, Digitaria
pauciflora, Chamaesyce deltoidea ssp. pinetorum,
[[Page 70307]]
and Dalea carthagenensis var. floridana are listed under the Act, the
State of Florida's Endangered Species Act (Florida Statutes 581.185) is
automatically invoked, which would also prohibit take of these plants
and encourage conservation by State government agencies. Further, the
State may enter into agreements with Federal agencies to administer and
manage any area required for the conservation, management, enhancement,
or protection of endangered species (Florida Statutes 581.185). Funds
for these activities could be made available under section 6 of the Act
(Cooperation with the States). Thus, the Federal protection afforded to
these plants by listing them as threatened or endangered species would
be reinforced and supplemented by protection under State law.
Activities that the Service believes could potentially harm these
four plants include, but are not limited to:
(1) Actions that would significantly alter the hydrology or
substrate, such as ditching or filling. Such activities may include,
but are not limited to, road construction or maintenance, and
residential, commercial, or recreational development.
(2) Actions that would significantly alter vegetation structure or
composition, such as clearing vegetation for construction of
residences, facilities, trails, and roads.
(3) Actions that would introduce nonnative species that would
significantly alter vegetation structure or composition. Such
activities may include, but are not limited to, residential and
commercial development, and road construction.
(4) Application of herbicides, or release of contaminants, in areas
where these plants occur. Such activities may include, but are not
limited to, natural resource management, management of right of ways,
residential and commercial development, and road construction.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Service's
South Florida Ecological Services Field Office (see FOR FURTHER
INFORMATION CONTACT).
Critical Habitat
Section 3(5)(A) of the Act defines critical habitat as ``(i) the
specific areas within the geographical area occupied by the species, at
the time it is listed . . . on which are found those physical or
biological features (I) essential to the conservation of the species
and (II) which may require special management considerations or
protection; and (ii) specific areas outside the geographical area
occupied by the species at the time it is listed upon a determination
by the Secretary that such areas are essential for the conservation of
the species. Section 3(3) of the Act defines conservation as to use and
the use of all methods and procedures which are necessary to bring any
endangered species or threatened species to the point at which the
measures provided pursuant to the Act are no longer necessary.''
Section 4(a)(3) of the Act, as amended, and implementing
regulations (50 CFR 424.12), require that, to the maximum extent
prudent and determinable, the Secretary will designate critical habitat
at the time the species is determined to be an endangered or threatened
species. Our regulations (50 CFR 424.12(a)(1)) state that the
designation of critical habitat is not prudent when one or both of the
following situations exist:
(1) The species is threatened by taking or other human activity,
and identification of critical habitat can be expected to increase the
degree of threat to the species, or
(2) Such designation of critical habitat would not be beneficial to
the species.
There is currently no imminent threat of take attributed to
collection or vandalism under Factor B for these species, and
identification and mapping of critical habitat is not expected to
initiate any such threat. Therefore, in the absence of finding that the
designation of critical habitat would increase threats to a species, if
there are any benefits to a critical habitat designation, a finding
that designation is prudent is warranted. Here, the potential benefits
of designation include: (1) Triggering consultation under section 7 of
the Act, in new areas for actions in which there may be a Federal nexus
where it would not otherwise occur because, for example, it is
unoccupied; (2) focusing conservation activities on the most essential
features and areas; (3) providing educational benefits to State or
county governments or private entities; and (4) preventing people from
causing inadvertent harm to these species.
Because we have determined that the designation of critical habitat
will not likely increase the degree of threat to the species and may
provide some measure of benefit, we determine that designation of
critical habitat is prudent for Sideroxylon reclinatum ssp.
austrofloridense, Digitaria pauciflora, Chamaesyce deltoidea ssp.
pinetorum, and Dalea carthagenensis var. floridana.
Our regulations (50 CFR 424.12(a)(2)) further state that critical
habitat is not determinable when one or both of the following
situations exists: (1) information sufficient to perform required
analysis of the impacts of the designation is lacking; or (2) the
biological needs of the species are not sufficiently well known to
permit identification of an area as critical habitat. On the basis of a
review of available information, we find that critical habitat for
Sideroxylon reclinatum ssp. austrofloridense, Digitaria pauciflora,
Chamaesyce deltoidea ssp. pinetorum, and Dalea carthagenensis var.
floridana is not determinable because the specific information
sufficient to perform the required analysis of the impacts of the
designation is currently lacking.
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 proposed 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, 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).
Government-to-Government Relationship With Tribes
No Native American tribes are affected by the proposed rule.
[[Page 70308]]
References Cited
A complete list of references cited in this rulemaking is available
on the Internet at http://www.regulations.gov at Docket No. FWS-R4-ES-
2016-0090 and upon request from the South Florida Ecological Services
Field Office (see FOR FURTHER INFORMATION CONTACT).
Authors
The primary authors of this proposed rule are the staff members of
the South Florida 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--ENDANGERED AND THREATENED WILDLIFE AND PLANTS
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; 4201-4245; unless
otherwise noted.
0
2. In Sec. 17.12(h) add entries for ``Chamaesyce deltoidea ssp.
pinetorum'', ``Dalea carthagenensis var. floridana'', ``Digitaria
pauciflora'', and ``Sideroxylon reclinatum ssp. austrofloridense'' to
the List of Endangered and Threatened Plants in alphabetical order
under Flowering Plants to read as set forth below:
Sec. 17.12 Endangered and threatened plants.
* * * * *
(h) * * *
----------------------------------------------------------------------------------------------------------------
Listing citations and
Scientific name Common name Where listed Status applicable rules
----------------------------------------------------------------------------------------------------------------
FLOWERING PLANTS
* * * * * * *
Chamaesyce deltoidea ssp. Pineland sandmat.. Wherever found......... T [Federal Register
pinetorum. citation of the final
rule].
* * * * * * *
Dalea carthagenensis var. Florida prairie- Wherever found......... E [Federal Register
floridana. clover. citation of the final
rule].
* * * * * * *
Digitaria pauciflora........... Florida pineland Wherever found......... T Federal Register
crabgrass. citation of the final
rule].
* * * * * * *
Sideroxylon reclinatum ssp. Everglades bully.. Wherever found......... T [Federal Register
austrofloridense. citation of the final
rule].
* * * * * * *
----------------------------------------------------------------------------------------------------------------
Dated: September 29, 2016.
Stephen Guertin
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2016-24140 Filed 10-7-16; 8:45 am]
BILLING CODE 4333-15-P