2009 Federal Register, 74 FR 44238; Centralized Library: U.S. Fish and Wildlife Service

[Federal Register: August 27, 2009 (Volume 74, Number 165)]
[Proposed Rules]
[Page 44237-44267]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr27au09-29]

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Part III

Department of the Interior

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Fish and Wildlife Service

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50 CFR Part 17

Endangered and Threatened Wildlife and Plants; Designation of Critical
Habitat for Ambrosia pumila (San Diego ambrosia); Proposed Rule

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

[Docket No. FWS-R8-ES-2009-0054; 92210-1117-0000-B4]

50 CFR Part 17

RIN 1018-AW20

Endangered and Threatened Wildlife and Plants; Designation of
Critical Habitat for Ambrosia pumila (San Diego ambrosia)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to
designate critical habitat for Ambrosia pumila (San Diego ambrosia)
under the Endangered Species Act of 1973, as amended (Act). In total,
approximately 802 acres (ac) (324 hectares (ha)) of land are being
proposed for designation as critical habitat. The proposed critical
habitat is located in Riverside and San Diego Counties, California.

DATES: We will consider comments we receive on or before October 26,
2009. We must receive requests for public hearings, in writing, at the
address shown in the FOR FURTHER INFORMATION CONTACT section by October
13, 2009.

ADDRESSES: You may submit comments by one of the following methods:
Federal eRulemaking Portal: http://
www.regulations.gov. Follow the instructions for submitting comments to
Docket No. FWS-R8-ES-2009-0054.
U.S. mail or hand-delivery: Public Comments Processing,
Attn: FWS-R8-ES-2009-0054; Division of Policy and Directives
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive,
Suite 222; Arlington, VA 22203.
We will post all comments on http://www.regulations.gov. This
generally means that we will post any personal information you provide
us (see the Public Comments section below for more information).

FOR FURTHER INFORMATION CONTACT: Jim Bartel, Field Supervisor, U.S.
Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 6010
Hidden Valley Road, Suite 101, Carlsbad, CA 92011; telephone (760) 431-
9440; facsimile (760) 431-5901. If you use a telecommunications device
for the deaf (TDD), call the Federal Information Relay Service (FIRS)
at (800) 877-8339.

SUPPLEMENTARY INFORMATION:

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 government
agencies, the scientific community, industry, or other interested party
concerning this proposed rule. We particularly seek comments
concerning:
(1) The reasons why we should or should not designate habitat as
``critical habitat'' under section 4 of the Endangered Species of 1973,
as amended (Act) (16 U.S.C. 1531 et seq.), including whether there are
threats to the species from human activity, the degree of which can be
expected to increase due to the designation, and whether that increase
in threat outweighs the benefit of designation such that the
designation is not prudent.
(2) Specific information that may assist us in clarifying or
identifying more specific primary constituent elements (PCEs). There is
a lack of specific information available regarding what constitutes
physical and biological features essential to the conservation of this
species. Additionally, the available information does not identify a
consistent pattern in specific life-history requirements and habitat
types where Ambrosia pumila is found. For these reasons, the PCEs in
this proposed rule are broad and based on our assessment of the
ecosystem settings in which the species has most frequently been
detected and our best assessment regarding its life history requisites.
We specifically seek information that may assist us in defining those
physical and biological features essential to the conservation of the
species which may require special management considerations or
protection, or in identifying specific areas outside the geographical
area occupied by the species at the time it was listed that may be
essential to the conservation of the species. In particular, answers to
the following questions may be helpful to clarify or identify more
specific PCEs of Ambrosia pumila habitat:
Does the species reproduce via seed? If so, does the
species rely on some aspect of its environment to trigger seed
germination?
What are the key factors determining why the species
occupies the particular areas it occupies (but not other areas with the
same habitat type)? For example, what role does proximity to waterways
or vernal pools play?
(3) The appropriateness of designating critical habitat for this
species. If the broad essential physical and biological features
proposed for Ambrosia pumila habitat cannot be defined more
specifically, or we cannot reasonably identify essential habitat for
this species based on our evaluation of information received, it may be
difficult to identify specific areas as critical habitat for this
species. This may be the case if specific information regarding what
constitutes essential habitat for this species cannot be obtained, or
if the data obtained suggest that the species can effectively carry out
all necessary life functions in a range of habitat types and conditions
(i.e., there may not be specific habitat features essential to the
conservation of the species).
(4) Specific information on:
The amount and distribution of Ambrosia pumila habitat
included in this proposed rule,
What areas occupied at the time of listing that contain
features essential for the conservation of the species should we
include or exclude in the designation and why, and
What areas not occupied at the time of listing are
essential to the conservation of the species and why.
(5) How the proposed critical habitat boundaries could be refined
to more closely circumscribe the areas identified as essential. We also
seek recommendations to improve the methodology used to delineate the
areas proposed as critical habitat; especially comments regarding how
we might more accurately estimate the additional surface area beyond
the visible surface area covered by the aerial stems that we need to
include for each occurrence of Ambrosia pumila in the critical habitat
designation to ensure that habitat areas do not exclude unseen
underground portions of A. pumila plants (see step number 4 in the
Methods section below).
(6) Land use designations and current or planned activities in the
areas proposed as critical habitat and their possible impacts on the
species and the proposed critical habitat.
(7) Any probable economic, national security, or other relevant
impacts of designating any area that may be included in the final
designation. We are particularly interested in any impacts on small
entities, and the benefits of including or excluding areas that exhibit
these impacts.
(8) Any issues with the exclusions being considered under section
4(b)(2) of the Act as part of this proposed designation, or reasons why
any proposed critical habitat not considered for exclusions should be
excluded.
(9) Any special management considerations or protections that the
proposed critical habitat may require.
(10) Whether we could improve or modify our approach to designating

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critical habitat in any way to provide for greater public participation
and understanding, or to better accommodate public concerns and
comments.
(11) Whether the benefit of an exclusion of any particular area
outweighs the benefit of inclusion under section 4(b)(2) of the Act, in
particular for those areas covered by the Western Riverside County
Multiple Species Habitat Conservation Plan (Western Riverside MSHCP),
and Subarea Plans (City of San Diego and County of San Diego) under the
San Diego Multiple Species Conservation Program (MSCP), and specific
reasons why.
(12) Whether the benefit of excluding the area proposed as critical
habitat within the City of Oceanside in San Diego County (Subunit 4C)
under section 4(b)(2) of the Act outweighs the benefit of including
this area as critical habitat, and specific reasons why. The City of
Oceanside is working on a Subarea Plan under the Northwestern San Diego
County Multiple Habitat Conservation Plan (MHCP) in cooperation with
the Service.
Our final determination concerning critical habitat for Ambrosia
pumila will take into consideration all written comments and comments
received during a public hearing, should one be requested, and any
additional information we receive during the public comment period.
These comments will be included in the public record for this
rulemaking. Our final determination will also incorporate all comments
requested of peer reviewers and received during the comment period.
Finally, our final determination concerning critical habitat will
consider all written comments and any additional information we receive
during the comment period for the draft Economic Analysis (DEA). On the
basis of peer reviewer and public comments, we may, during the
development of our final determination, find that areas within those
proposed do not meet the definition of critical habitat, that some
modifications to the described boundaries are appropriate, or that
areas are not appropriate for exclusion under section 4(b)(2) of the
Act.
You may submit your comments and materials concerning this proposed
rule by one of the methods listed in the ADDRESSES section.
We will post your entire comment--including your personal
identifying information--on http://www.regulations.gov. If you provide
personal identifying information in addition to the required items
specified in the previous paragraph, such as your street address, phone
number, or e-mail address, 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.
Comments and materials we receive, as well as supporting
documentation we used in preparing this proposed rule, will be
available for public inspection at http://www.regulations.gov, or by
appointment, during normal business hours, at the U.S. Fish and
Wildlife Service, Carlsbad Fish and Wildlife Office (see FOR FURTHER
INFORMATION CONTACT).
You may obtain copies of the proposed rule by mail from the
Carlsbad Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT)
or by visiting the Federal eRulemaking Portal at http://
www.regulations.gov.

Background

It is our intent to discuss only those topics directly relevant to
the designation of critical habitat in this proposed rule. This rule
incorporates new information on the biology, distribution, and
abundance of Ambrosia pumila that we did not discuss in the 2002 final
listing rule for this species (67 FR 44372). For more information on A.
pumila, refer to that final listing rule, which was published in the
Federal Register on July 2, 2002.

Previous Federal Actions

Ambrosia pumila was listed as an endangered species on July 2, 2002
(67 FR 44372). Designation of critical habitat was found to be prudent
in the proposed (64 FR 72993; December 29, 1999) and final listing
rules, but was deferred due to budgetary constraints and higher listing
priorities. The Center for Biological Diversity filed a complaint in
the U.S. District Court for the Southern District of California on
December 19, 2007, challenging failure of the Service to designate
critical habitat for four endangered plants, including A. pumila
(Center for Biological Diversity v. United States Fish and Wildlife, et
al., Case No. 07-CV-2378 NLS). The April 11, 2008, settlement agreement
stipulates that the Service shall submit a determination as to whether
it is prudent to designate critical habitat for A. pumila, and if
prudent, a proposed critical habitat designation to the Federal
Register for publication on or before August 20, 2009, and submit a
final critical habitat designation to the Federal Register for
publication on or before August 19, 2010. In this proposed critical
habitat rule, we reaffirm that determination of critical habitat for A.
pumila is prudent. However, we may revisit our prudency determination
following additional review and consideration of information we receive
during the public comment period.

Species Description

Ambrosia is a genus comprising 35 to 50 wind-pollinated annual and
perennial plant species in the Asteraceae (sunflower) family. Members
of this genus occur predominantly in the Western Hemisphere, especially
North America. Species are generally found in arid or semiarid areas,
while some are weeds of cultivated fields or strand species of Pacific
and Caribbean beaches (Payne 1976, p. 169).
Ambrosia pumila is a clonal herbaceous perennial. Individual stems
are generally 5 to 30 centimeters (cm) (2 to 12 inches (in)) tall, but
may grow to 50 cm (20 in), and are densely covered with short hairs.
The leaves are two to four times pinnately divided into many small
segments and are covered with short, soft, gray-white, appressed (lying
flat on surface) hairs. The species has separate male and female
flowers on the same plant (monoecious). The male flowers have no
petals, are yellow to translucent, and are borne in clusters on
terminal flower stalks. The female flowers have no petals and are
yellowish-white. Female flowers are in clusters in the axils of the
leaves below the male flower clusters (Nuttall 1840, pp. 344-345; Gray
1882, p. 217; Munz 1935, p. 544; Keck 1959, p. 1103; Ferris 1960, p.
148; Munz 1974, p. 112; Beauchamp 1986, p. 94; Payne 1993, p. 194).
Female flowers produce a dry, single-seeded fruit called an achene.
References to seeds in this document refer to the single-seeded fruits.
Ambrosia pumila spreads vegetatively by means of slender, branched,
underground root-like rhizomes from which new aboveground stems (aerial
stems or ramets) arise each year (Nuttall 1840, p. 344; Munz 1974, p.
112; Payne 1993, p. 194). This growth pattern results in numerous
aerial stems interconnected by a system of rhizomes, called a clone.
All aerial stems growing from the same root system are genetically
identical and represent a single individual A. pumila plant (called a
genet) (Harper 1977, p. 26). Growing rhizomes extend underground beyond
the aboveground limit of the aerial stems into adjacent suitable
habitat, allowing rhizomes of adjacent individuals to intermingle. The
underground interconnections can break or disintegrate, resulting in
aerial stems that are genetically identical but physically separate
(McGlaughlin and Friar 2007, p. 319). The extent to which

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rhizomes are capable of spreading has been observed only in individuals
translocated to previously unoccupied sites. For example, A. pumila
individuals transplanted on the San Diego National Wildlife Refuge in
January 2008 were documented to produce new stems several inches away
within 10 months (by November 2008). Additionally, A. pumila
individuals transplanted in 1997 to an unoccupied site at Pilgrim Creek
just south of Marine Corps Base Camp Pendleton in San Diego County were
documented to produce new stems up to 70 in (178 cm) from the original
stems within 2 years (by 1999) (Johnson et al. 1999, p. 3).
Because of the clonal nature of Ambrosia pumila's growth, it is not
possible to directly determine the number of genetically distinct
plants present in an area simply by counting stems (McGlaughlin and
Friar 2007, p. 320). McGlaughlin and Friar's (2007, p. 323) analysis of
clonality in A. pumila determined that the aerial stem-to-genet ratio
is roughly 10-to-1 on average (about 1 genet for every 10 aerial stems
counted in a patch (cluster of stems)). A patch constitutes a spatially
distinct cluster of stems within an occurrence, whereas an occurrence
constitutes a group of individuals separated from the next nearest
group of individuals by a distance greater than or equal to 0.25 mile
(mi) (0.40 kilometer (km)).

Habitat

Ambrosia pumila occurs primarily on upper terraces of rivers and
drainages (Beauchamp 1986, p. 94; Johnson et al. 1999, p. 1;
McGlaughlin and Friar 2007, p. 321; California Natural Diversity
Database data report for A. pumila 2008 (CNDDB 2008)); however, several
patches of the plant occur within the watershed of a large vernal
(ephemeral) pool in the Skunk Hollow preserve in Riverside County
(Dudek 2003, p. P-326; CNDDB 2008). Within these areas, the species is
found in open grassland of native and nonnative plant species, and
openings in coastal sage scrub (Johnson et al. 1999, p. 1; Dudek 2000,
p. 18; Dudek 2003, p. P-330; CNDDB 2008), and primarily on sandy loam
or clay soils (Johnson et al. 1999, p. 1; Dudek 2000, p. 18; CNDDB
2008; USDA 2008). The species may also be found in ruderal habitat
types (disturbed communities containing a mixture of native and
nonnative grasses and forbs) such as fire fuel breaks and edges of dirt
roadways (Beauchamp 1986, p. 94; Payne 1993, p. 194; CNDDB 2008).
Nonnative grassland and ruderal habitat types provide adequate habitat
for A. pumila; however, nonnative plants can out-compete A. pumila
plants for resources in some situations if not managed. Occurrences are
disjunct (generally 1 or more miles (1.6 or more km) apart) and most
locations have been subjected to disturbance such as nonnative plant
invasion, mining activities, development, grading, and human
encroachment on foot, horses, or vehicles (CNDDB 2008).
It is unclear why Ambrosia pumila consistently occurs in areas near
waterways such as upper terraces of rivers or other water bodies. The
areas where the species is found do not necessarily provide high levels
of soil moisture, and A. pumila is adapted to dry conditions (Keck
1959, p. 1103; Munz 1974, p. 112; Dudek 2000, Appendix A; CNLM 2008, p.
18). Additionally, Service biologists have observed green (that is, not
desiccated) aerial stem shoots of A. pumila after small amounts of
precipitation and after other vegetation in the observed area had
desiccated. Ambrosia pumila may require periodic flooding for dispersal
of seeds and roots dislodged during flooding, seed germination, or some
other segment of its life cycle. Further, areas subject to periodic
flooding appear to be less amenable to competing nonnative and native
plants.

Life History

The reproductive biology of Ambrosia pumila has not been studied to
the same extent as the more common Ambrosia species, such as A.
artemisiifolia (common ragweed) and A. trifida (giant ragweed) (Dudek
2000, p. 16). Thus, little is known about its pollination system, seed
production, seed dispersal, and germination (Dudek 2000, p. 16; Dudek
2003, p. P-331; McGlaughlin and Friars 2007, p. 320).
Aerial stems of Ambrosia pumila sprout from their underground
rhizomes in early spring after winter rains, and flower between May and
October (Keck 1959, p. 1103). Recently, however, Service biologists
observed aerial stems sprouting under dry conditions in late fall
(Folarin 2008, pers. comm.). The plants senesce after the growing
season, leaving the root system in place from which new aerial stems
may sprout when environmental conditions are appropriate (Keck 1959, p.
1103).
Ambrosia pumila is presumed to be wind-pollinated because most
other species of Ambrosia are wind-pollinated, and because biological
pollinators have not been observed visiting A. pumila flowers (Johnson
et al. 1999, p. 4; Dudek 2000, p. 16; Dudek 2003, p. P-331).
Alternatively, pollinator(s) of A. pumila may have been extirpated
(Dudek 2003, p. P-331). The species is presumed to be capable of self-
pollination and of being self-fertile (i.e., self-compatible, where
pollen from an individual plant can fertilize an ovule on the same
plant, resulting in production of viable seed) because other species of
Ambrosia are capable of self-pollination (Payne 1976, pp. 171-172). The
configuration of the male flowers in relation to the female flowers
also implies opportunity for self-pollination (Dudek 2000, p. 16).
However, studies are needed to determine whether viable seed is
produced through self-pollination in this species (Johnson et al. 1999,
p. 4; Dudek 2000, p. 16; Dudek 2003, p. P-332; McGlaughlin and Friars
2007, p. 329).
Ambrosia pumila is thought to have limited sexual reproductive
output due to low production of viable seed (Johnson et al. 1999, pp.
1-5; Dudek 2000, pp. 16-17; Dudek 2003, pp. P-331-P-332). Low seed
production in this species is inferred by the lack of fertile fruits on
all but a few preserved A. pumila museum specimens (Wallace 1999, pers.
comm.), and field observers have found seed production in A. pumila to
be low (Dudek 2000, p. 17; Dudek 2003, p. P-332). Specific germination
requirements of A. pumila seed are unknown. A 1998 germination study
using 22 A. pumila seeds of unknown viability collected from 3 sites at
Mission Trails Regional Park did not result in any germination of
seedlings (Dudek 2000, Appendix B). The lack of germination could have
been due to the seeds being nonviable or to inappropriate germination
conditions. Regardless of what proportion of A. pumila seeds are
viable, low seed production implies that little sexual reproduction is
occurring in this species. Low levels of sexual reproduction is not an
unusual condition in clonal plant species (Sackville et al. 1987, p.
54). This reduced sexual reproduction may negatively impact the ability
of the species to adapt to rapid environmental change or environmental
change over the long term, which is especially deleterious to a rare
species with disjunct occurrences such as A. pumila (Dudek 2000, p. 17;
Dudek 2003, p. P-332).
The dispersal strategy of Ambrosia pumila is unknown. Ambrosia
pumila seeds lack structures that facilitate dispersal by wind or
passing animals (Nuttall 1840, p. 344; Payne 1993, p. 194). The species
may depend on periodic flooding of nearby waterways for dispersal of
seeds and rhizomes that can produce new aerial stems (Dudek 2003, p. P-
332). The longevity of individual plants is also unknown,

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although plants with clonal growth patterns tend to be long-lived
(Watkinson and White 1985, pp. 44-45; Tanner 2001, p. 1980). Finally,
the longevity of seeds and potential for buried seed banks to develop
in the soil is unknown.

Genetics

Little is known about genetic diversity or genetic distribution of
Ambrosia pumila across its range. McGlaughlin and Friar (2007)
conducted a genetic study of A. pumila to address conservation and
management of the species. They found that each population they
examined contained multiple genetically distinct individuals, but no
individuals that occurred in more than one population. Therefore, they
concluded that in order to maintain a level of genetic diversity
capable of responding to variable ecological conditions, conservation
of the species should involve the protection and maintenance of as many
populations of A. pumila as possible (McGlaughlin and Friar 2007, pp.
319 and 329).

Geographic Range and Status

Ambrosia pumila is distributed in southern California from
northwestern Riverside County, south through western San Diego County,
to northwestern Baja California, Mexico (CNDDB 2008). It is generally
found at or below elevations of 1600 feet (ft) (487 meters (m)) in
Riverside County, and 600 ft (183 m) in San Diego County (CNDDB 2008).
When listed as endangered under the Act in 2002, 15 occurrences of A.
pumila were known in the United States: 3 in Riverside County and 12 in
San Diego County (67 FR 44372; July 2, 2002). As noted previously, the
term ``occurrence'' as used in this proposed critical habitat rule is
defined as one or more A. pumila plants more than 0.25 mi (0.40 km)
from another individual or group of individuals (Bittman 2002, in
litt.). More than 80 percent of the occupied sites identified in the
final listing rule were concentrated in the following 6 areas:
Near Alberhill about 2.1 mi (3.5 km) to the northwest of
the Nichols Road site in Riverside County;
Along Nichols Road in the City of Lake Elsinore, Riverside
County;
Near the Skunk Hollow vernal pool in southwestern
Riverside County;
Adjacent to State Route 76 in northern San Diego County;
Mission Trails Regional Park, in the City of San Diego,
San Diego County; and
San Diego National Wildlife Refuge near the unincorporated
community of Jamul in southern San Diego County.
According to information used to develop the final listing rule (67
FR 44372; July 2, 2002), roughly 44 ac (18 ha)) of habitat in San Diego
County was occupied by this species in 12 occurrences. This habitat
estimate only includes areas where A. pumila stems were found in the 5
to 10 years prior to listing in 2002. Similar area estimate data were
unavailable for the 3 occurrences in Riverside County.
Since this species was listed, one occurrence was identified in
Riverside County about 1 mile (1.6 km) south of Skunk Hollow along San
Diego aqueduct, from a survey report (AMEC 2006, pp. 12-13; CNDDB
2008), and one occurrence was identified in unincorporated San Diego
County on the west side of State Route 76, south of Olive Hill Road
(see ``Criteria Used to Identify Critical Habitat'' below). Also since
listing, we determined that one occurrence, on the west side of
Interstate 15 just north of Lake Hodges and south of Via Rancho Parkway
in San Diego County, previously identified as extirpated or not viable
in the final listing rule is now extant and viable.
The documented range of Ambrosia pumila in Mexico at the time of
listing extended from Cabo Colonet south to Lake Chapala in north-
central Baja California, Mexico (Burrascano and Hogan 1996, p. 8). Two
of these three occurrences were confirmed by David Hogan, formerly with
the Southwest Center for Biological Diversity (now Center for
Biological Diversity), and Cindy Burrascano of the California Native
Plant Society (CNPS), San Diego Chapter (Burrascano and Hogan 1996, p.
8). Although additional occurrences may have existed in Baja
California, the species was not considered to be widespread at the time
of listing due to the lack of appropriate habitat and impacts from
agriculture and urban development, especially near the coast
(Burrascano and Hogan1996, p. 8).
All currently known occurrences are believed to have been present
at the time of listing because plants with clonal growth patterns tend
to be long-lived (Watkinson and White 1985, pp. 44-45; Tanner 2001, p.
1980). Although stems may die and portions of the rhizome may
disintegrate over time, except under extreme conditions enough of the
rhizome survives from one growing season to the next to support
continued growth of an individual plant. Also, because the plants
produce very few if any seeds, the ability of the plant to disperse
into and colonize previously unoccupied areas is diminished. Since this
species was listed, no additional occurrences were documented in
Mexico; the occurrences along the west coast of Baja California between
Cabo Colonet and the U.S.-Mexico border are rapidly disappearing due to
recreational development and agriculture (Dudek 2003, p. P-330).

Critical Habitat

Background

Critical habitat is defined in section 3(5)(A) of the Act as:
(1) The specific areas within the geographical area occupied by the
species, at the time it is listed in accordance with the provisions of
section 4 of the Act, on which are found those physical or biological
features
(a) Essential to the conservation of the species, and
(b) Which may require special management considerations or
protection; and
(2) Specific areas outside the geographical area occupied by the
species at the time it is listed, upon a determination by the Secretary
of the Interior that such areas are essential for the conservation of
the species.
Conservation, as defined under section 3 of the Act, means the use
of all methods and procedures that are necessary to bring an endangered
or threatened species to the point at which the measures provided
pursuant to the Act are no longer necessary. Such methods and
procedures include, but are not limited to, all activities associated
with scientific resources management such as research, census, law
enforcement, habitat acquisition and maintenance, propagation, live
trapping and transplantation, and in the extraordinary case where
population pressures within a given ecosystem cannot otherwise be
relieved, may include regulated taking.
Critical habitat receives protection under section 7 of the Act
through the prohibition against Federal agencies carrying out, funding,
or authorizing activities that result in the destruction or adverse
modification of critical habitat. Section 7(a)(2) requires consultation
on Federal actions that may affect critical habitat. The designation of
critical habitat does not affect land ownership or establish a refuge,
wilderness, reserve, preserve, or other conservation area. Such
designation does not allow the government or public to access private
lands. Such designation does not require implementation of restoration,
recovery, or enhancement measures by the landowner. Where a landowner

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seeks or requests Federal agency funding or authorization for an
activity that may affect a listed species or critical habitat, the
consultation requirements of section 7(a)(2) would apply, but even in
the event of a destruction or adverse modification finding, the Federal
action agency's and the applicant's obligation is not to restore or
recover the species, but to implement reasonable and prudent
alternatives to avoid destruction or adverse modification of critical
habitat.
To be considered for inclusion in a critical habitat designation,
habitat within the geographical area occupied by the species at the
time of listing must contain physical and biological features that are
essential to the conservation of the species, and be included only if
those features may require special management considerations or
protection. Critical habitat designations identify, to the extent known
using the best scientific data available, habitat areas that provide
essential life cycle needs of the species; that is, areas on which the
physical and biological features are found laid out in the appropriate
quantity and spatial arrangement essential to the conservation of the
species. Under the Act and regulations at 50 CFR 424.12, we can
designate as critical habitat areas outside the geographical area
occupied by the species at the time it is listed only when we determine
that those areas are essential for the conservation of the species and
that designation limited to those areas occupied at the time of listing
would be inadequate to ensure the conservation of the species.
Section 4 of the Act requires that we designate critical habitat on
the basis of the best scientific and commercial data available.
Further, our Policy on Information Standards Under the Endangered
Species Act (published in the Federal Register on July 1, 1994 (59 FR
34271)), the Information Quality Act (section 515 of the Treasury and
General Government Appropriations Act for Fiscal Year 2001 (Pub. L.
106-554; H.R. 5658)), and our associated Information Quality
Guidelines, provide criteria, establish procedures, and provide
guidance to ensure that our decisions are based on the best scientific
data available. They require our biologists, to the extent consistent
with the Act and with the use of the best scientific data available, to
use primary and original sources of information as the basis for
recommendations to designate critical habitat.
When we are determining which areas should be proposed as critical
habitat, our primary source of information is generally the information
developed during the listing process for the species. Additional
information sources may include the recovery plan for the species,
articles in peer-reviewed journals, conservation plans developed by
States and counties, scientific status surveys and studies, biological
assessments, or other unpublished materials and expert opinion or
personal knowledge.
Habitat is dynamic, and species may move from one area to another
over time. We recognize that climate change may cause changes in the
arrangement of occupied habitat patches. Current climate change
predictions for terrestrial areas in the Northern Hemisphere indicate
warmer air temperatures, more intense precipitation events, and
increased summer continental drying (Field et al. 1999, pp. 1-3; Hayhoe
et al. 2004, p. 12422; Cayan et al. 2005, p. 6; Intergovernmental Panel
on Climate Change 2007, p. 11). However, predictions of climatic
conditions for smaller subregions such as California remain uncertain.
It is unknown at this time if climate change in California will result
in a warmer trend with localized drying, higher precipitation events,
or other effects. Thus, the information currently available on the
effects of global climate change and increasing temperatures does not
make sufficiently precise estimates of the location and magnitude of
the effects, so we are unable to determine what, if any, additional
areas would be needed. However, we recognize that critical habitat
designated at a particular point in time may not include all of the
habitat areas that we may later determine are necessary for the
recovery of the species. For these reasons, a critical habitat
designation does not signal that habitat outside the designated
critical habitat area is unimportant or may not be required for
recovery of the species.
Areas that are important to the conservation of the species, but
are outside the critical habitat designation, will continue to be
subject to conservation actions implemented under section 7(a)(1) of
the Act. Areas that support populations are also subject to the
regulatory protections afforded by the section 7(a)(2) jeopardy
standard, as determined on the basis of the best available scientific
information at the time of the agency action. Federally funded or
permitted projects affecting listed species outside their designated
critical habitat areas may still result in jeopardy findings in some
cases. Similarly, critical habitat designations made on the basis of
the best available information at the time of designation will not
control the direction and substance of future recovery plans, habitat
conservation plans (HCPs), or other species conservation planning
efforts if information available at the time of these planning efforts
calls for a different outcome.

Physical and Biological Features

In accordance with section 3(5)(A)(i) of the Act and regulations at
50 CFR 424.12, in determining which areas within the geographical area
occupied by the species at the time of listing to propose as critical
habitat, we consider the physical and biological features that are
essential to the conservation of the species and that may require
special management considerations or protection. Those features are the
primary constituent elements (PCEs) laid out in the appropriate
quantity and spatial arrangement for the conservation of the species.
The PCEs include, but are not limited to:
(1) Space for individual and population growth and for normal
behavior;
(2) Food, water, air, light, minerals, or other nutritional or
physiological requirements;
(3) Cover or shelter;
(4) Sites for breeding, reproduction, and rearing (or development)
of offspring; and
(5) Habitats that are protected from disturbance or are
representative of the historical, geographical, and ecological
distributions of a species.
Little is known about the habitat specificity and characteristics
of this species. Therefore, the PCEs for Ambrosia pumila are based on
our assessment of the ecosystem settings in which the species has most
frequently been detected.

Space for Individual and Population Growth and for Normal Behavior

Clonal Growth--Rhizome Spread and New Aerial Stems
Individual Ambrosia pumila plants spread by underground rhizomes to
produce a group of genetically identical aerial stems--a clone. Growing
rhizomes extend underground beyond the extent of the aerial stems into
adjacent suitable habitat, and rhizomes of adjacent plants likely
intermingle to a degree. The distance rhizomes extend beyond the
standing aerial stems is difficult to measure because of the difficulty
in investigating an intact, underground rhizome system.
The extent and configuration of the visible portion (aerial stems)
of A. pumila patches can change from one growing season to the next
(Martin 2005, p. 3; City of San Diego 2008a, p.

[[Page 44243]]

1). For example, see Figure 4 in Martin 2005, in which patches of A.
pumila are shown to change in shape and size (up to several square
meters) from 2000 to 2005, with some patches not producing any stems in
2005 (some of the patches that did not produce stems in 2005 were
observed to produce stems in 2008 (Folarin 2008, pers. comm.)). These
changes in patch size and shape are perhaps due to differences in
available moisture or competition from other plants (Martin 2005, p. 3;
City of San Diego 2008a, p. 1). Based on these and other observations,
we conclude that the rhizome system of a group of A. pumila stems
likely occupies a greater underground area than occupied by the stems
above ground at any given time, with aerial stems produced only where
conditions are appropriate. Thus, to ensure that a habitat area does
not exclude unseen underground portions of A. pumila plants, the area
needs to include additional surface area beyond the visible surface
area covered by the aerial stems.
Germination of Seeds and Spread of Seedlings
It is unclear to what extent and with what frequency Ambrosia
pumila reproduces by seed. Presuming at least low rates of sexual
reproduction, space is needed for new plants to germinate, grow, and
spread. However, we are not aware of any research that would provide
the information needed to assess the species' germination and seedling
needs.

Food, Water, Air, Light, Minerals, or Other Nutritional or
Physiological Requirements

Water
Specific water needs of the species are unknown. Ambrosia pumila is
adapted to dry conditions which occur annually throughout its range
(Keck 1959, p. 1103; Munz 1974, p. 112; Dudek 2000, Appendix A; CNLM
2008, p. 18). Service biologists have observed green (not desiccated)
aerial stem shoots after small amounts of precipitation and after
annual vegetation in the area had desiccated, implying that either A.
pumila requires less water than other grassland plants, that the
underground perennial rhizome system has some capacity to store enough
water to sustain growth, or both (Folarin 2008, pers. comm.).
Additionally, we believe that periodic flooding may be necessary to
some segment of the plant's life history (such as seed germination,
dispersal of seeds and rhizomes) or to maintain some essential aspect
of its habitat, because of the indicator that the plant is always found
on river terraces or within the watersheds of vernal pools.
Light
Ambrosia pumila is limited to open or low-growing plant
communities, which implies that the species is not shade-tolerant
(Dudek 2000, pp. 18-19). Ambrosia pumila stems amid taller vegetation
obtain adequate sunlight by growing taller (etiolation) and more
slender compared to those in more open areas (Dudek 2000, p. 19), which
also implies the species is not shade-tolerant.
Soil
Ambrosia pumila is found primarily on sandy loam or clay soils
including (but not limited to) the Placentia (sandy loam), Diablo
(clay), and Ramona (sandy loam) series (Dudek 2000, Appendix A; CNDDB
2008). These soil types likely are particularly conducive to the growth
and persistence of A. pumila because it is rarely found growing on
other substrate types (such as gravel).
Chemical soil attributes and other abiotic and biotic
characteristics have been measured and documented for Ambrosia pumila
occurrences at Skunk Hollow (Riverside County), and Mission Trails
Regional Park and San Diego National Wildlife Refuge (San Diego County)
(Dudek 2000, Appendix A; CNLM 2008, pp. 6-7, 12, and 18), including pH,
percent organic matter, soil moisture, and elemental composition. These
measurements did not provide consistent results across the range of the
species; thus, we are unable to make generalizations as to needs of the
species as far as soil attributes are concerned.
Temperature
We have seen no reports of data on the tolerance of Ambrosia pumila
to climatic extremes. Temperature is thought to potentially play a role
in inducing (or prohibiting) seed germination (Johnson 1999, p. 5),
although there is limited information at this time as to whether this
species reproduces via seed.

Sites for Breeding, Reproduction, or Rearing (or Development) of
Offspring

As stated above under the ``Life History'' section, little is known
about sexual reproduction in Ambrosia pumila. Because occurrences are
consistently found on the upper terraces of rivers and other waterways,
periodic flooding of these waterways likely plays or likely has played
a role in the life history of the plant. For example, Johnson (1999, p.
5) postulated that A. pumila seeds may require soaking in flood waters
or scarification as they are churned about with debris in flood waters
to germinate. Additionally, A. pumila may depend on floods to disperse
rhizomes and seeds (Dudek 2003, p. P-332) and to create space for new
stems by removing or limiting the growth of competitors.
Presuming Ambrosia pumila is wind-pollinated, as discussed in the
``Life History'' section above, the species requires sufficient airflow
through inflorescences to pick up and carry pollen (McGlaughlin and
Friars 2007, p. 329). This is another reason (in addition to not being
shade-tolerant) that A. pumila may require habitat containing primarily
low-growing plants--low-growing plants do not block or dramatically
reduce airflow to plants of A. pumila's stature, which is generally
less than 12 in (30 cm) tall (McGlaughlin and Friars 2007, p. 329).
Ambrosia pumila is presumed to be self-compatible (an individual
can produce viable seed using its own pollen), but this aspect of the
species' reproductive strategy has not been well examined. In a recent
study, another Ambrosia species previously thought to be self-
compatible was found not to be self-compatible (Friedman and Barrett
2008, p. 4). If A. pumila likewise is not self-compatible, genetically
distinct individuals in close proximity to one another may be crucial
to maintaining sexual reproduction in the species (McGlaughlin and
Friars 2007, p. 329).

Habitats Protected from Disturbance or Representative of the
Historical, Geographical, and Ecological Distributions of the Species

Ambrosia pumila occurs most frequently on upper terraces of rivers
(flat or gently sloping areas of 0 to 42 percent slopes are typical for
terraces on which A. pumila occurrences are found, near, but not
directly adjacent to, the river channel) and other drainages in western
Riverside County, western San Diego County, and northwestern Baja
California (Beauchamp 1986, p. 94; Johnson et al. 1999, p. 1;
McGlaughlin and Friar 2007, p. 321; CNDDB 2008). These areas are or
have been associated with a natural flood disturbance regime. The
species is primarily associated with grassland and ruderal communities,
and openings in coastal sage scrub (Johnson et al. 1999, p. 1; Dudek
2000, p. 18; Dudek 2003, p. P-330; CNDDB 2008). In Riverside County, A.
pumila occurs in ruderal and nonnative grassland communities adjacent
to creeks and other smaller drainages (for example, Temescal
(Alberhill) Creek and Santa Gertrudis Creek) (Dudek 2003, p. P-326;

[[Page 44244]]

CNDDB 2008). Ambrosia pumila also occurs in nonnative grassland
community adjacent to and within the watershed of Skunk Hollow vernal
pool in Riverside County (Dudek 2003, p. P-326; CNDDB 2008). In San
Diego County, A. pumila is more often found adjacent to larger
waterways (for example, San Luis Rey River, San Diego River, and
Sweetwater River), although the species is also often found associated
with smaller drainages and washes (CNDDB 2008).
Occurrences in Riverside County are found at much higher elevation
than in San Diego County. For example, the occurrence at Skunk Hollow
in Riverside County is 1,350 ft (411 m) above sea level, while the
occurrences at Mission Trails Regional Park and San Diego National
Wildlife Refuge in San Diego County are about 315 ft and 360 ft (96 m
and 110 m) above sea level, respectively (CNLM 2008, p. 7)).
The documented range of Ambrosia pumila in Mexico at the time of
listing extended from Cabo Colonet south to Lake Chapala in north-
central Baja California. We have no information regarding additional
occurrences in Mexico, or the physical and biological features
essential to the conservation of the species there.

Primary Constituent Elements for Ambrosia pumila

Under the Act and its implementing regulations, we are required to
identify the known physical and biological features, called primary
constituent elements (PCEs), within the geographical area occupied by
Ambrosia pumila at the time of listing that are essential to the
conservation of the species and which may require special management
considerations or protection. Again, the physical and biological
features are those PCEs laid out in a specific spatial arrangement and
quantity determined to be essential to the conservation of the species.
Because not much is known about the specific needs and characteristics
of this species, the PCEs are based on observed traits of the habitat
types in which the species is most often found. All areas we are
proposing as critical habitat for A. pumila were occupied at the time
the species was listed, occur within the species' historical geographic
range, and contain physical and biological features to support at least
one life-history function.
Based on the above needs and our current knowledge of the life
history, biology, and ecology of Ambrosia pumila, and the
characteristics of the areas where the species is known to occur, we
have identified two PCEs for A. pumila:
1. Sandy loam or clay soils (regardless of disturbance status),
including (but not limited to) the Placentia (sandy loam), Diablo
(clay), and Ramona (sandy loam) soil series that occur on near (but not
directly adjacent to) a river, creek, or other drainage, or within the
watershed of a vernal pool, and that occur on an upper terrace (flat or
gently sloping areas of 0 to 42 percent slopes are typical for terraces
on which A. pumila occurrences are found).
2. Grassland or ruderal habitat types, or openings within coastal
sage scrub, on the soil types and topography described in PCE 1, that
provide adequate sunlight, and airflow for wind pollination.
Based on our current knowledge of the needs of the species, we
believe the need for space for individual and population growth and
normal behavior is met by PCE 2, and areas for reproduction, water,
light, and soil are provided by PCEs 1 and 2. These areas provide
nutrients, moisture, and proximity to water features that provide
periodic flooding presumed necessary for the plant's persistence.
With this proposed designation of critical habitat, we intend to
conserve the physical and biological features that are essential to
support the life-history functions that are the basis for the proposal.
All units and subunits proposed in this rule as critical habitat
contain sufficient PCEs in the appropriate quantity and spatial
arrangement to provide for one or more of the life-history functions of
A. pumila.
We are soliciting public comment for information to help us more
specifically identify PCEs and essential habitat for Ambrosia pumila.
There is a lack of available information regarding what constitutes
essential habitat for this species. Additionally, the available
information does not identify a consistent pattern in specific life-
history requirements and habitat types where Ambrosia pumila is found.
For these reasons, the PCEs in this proposed rule are broad and based
on our assessment of the ecosystem settings in which the species has
most frequently been detected and speculation regarding its life
history. We specifically seek information that may assist us in
defining those physical and biological features essential to the
conservation of the species which may require special management
considerations or protection, or in identifying specific areas outside
the geographical area occupied by the species at the time it was listed
that may be essential to the conservation of the species (see questions
2 and 3 in the Public Comments section).

Special Management Considerations or Protection

When designating critical habitat, we assess whether the physical
and biological features within the geographical area occupied by the
species at the time of listing contain features that are essential to
the conservation of the species and that may require special management
considerations or protection. All areas proposed for designation as
critical habitat will require some level of management to address the
current and future threats to the physical and biological features
essential to the conservation of Ambrosia pumila. In all units, special
management will be required to ensure that the habitat is able to
provide for the growth and reproduction of the species.
Researchers estimate that Ambrosia pumila historically was known
from over 50 locations in San Diego and Riverside Counties, but the
number of extant occurrences has been dramatically reduced as much of
its habitat has been impacted by human activities (Burrascano and Hogan
1997, p. 7; Dudek 2000, p. 17; CNDDB 2008). A detailed discussion of
threats to A. pumila and its habitat can be found in the final listing
rule (67 FR 44372). The primary threats impacting the physical and
biological features essential to the conservation of A. pumila that may
require special management considerations or protection within the
proposed critical habitat include, but are not limited to, the
following (67 FR 44372):
Habitat destruction caused by urban development, including
highway and utility corridor construction and maintenance, highway
expansion, and development of recreational facilities (such as golf
courses and campgrounds). These activities can remove the PCEs by
removing soil (by grading) and changing Ambrosia pumila habitat to
urban land, which is unsuitable for the species.
Soil compaction caused by the creation of trails by
hikers, horses, and vehicles. Ambrosia pumila appears to be tolerant to
some level of disturbance caused by trail creation and use; it is often
found in the disturbed areas along margins of dirt trails. However, it
is found less often on trails, implying that although the appropriate
soil type might be present, soil compaction can alter the physical
characteristics of the soil such that the soil can no longer support
growth of the plant.

[[Page 44245]]

Habitat alteration caused by nonnative plant species that
may, if present in large enough numbers, change the plant community to
the extent that A. pumila plants can no longer receive adequate
sunlight and airflow.
Alteration of hydrology and floodplain dynamics (such as
channelization and water diversions) (an additional threat not
discussed in the listing rule), which can change the frequency of
flooding in occupied areas or eliminate periodic flooding presumed
necessary for the plant's persistence altogether, or change groundwater
levels that could change the plant community to the extent that A.
pumila plants can no longer receive adequate sunlight and airflow.
Special management considerations or protection are required within
critical habitat areas to address these threats. Management activities
that could ameliorate these threats include fencing Ambrosia pumila
occurrences and providing signage to discourage encroachment by hikers,
horses, and off road vehicle users; control of nonnative plants using
methods shown to be effective (for examples, see CNLM 2008); guiding
the design of development projects to avoid impacts to A. pumila
habitat; and restoring and maintaining hydrology and floodplain
dynamics of waterways associated with A. pumila occurrences where
feasible.
The designation of critical habitat does not imply that lands
outside of critical habitat do not play an important role in the
conservation of Ambrosia pumila. Federal activities that may affect
areas outside of critical habitat are still subject to review under
section 7 of the Act if they may affect A. pumila. The prohibitions of
section 9 of the Act applicable to listed plant species also continue
to apply both inside and outside of designated critical habitat.

Criteria Used To Identify Critical Habitat

As required by section 4(b) of the Act, we used the best scientific
and commercial data available in determining areas within the
geographical area occupied at the time of listing that contain the
features essential to the conservation of Ambrosia pumila, and areas
outside of the geographical area occupied at the time of listing that
are essential to the conservation of A. pumila, or both. All essential
areas were occupied at the time of listing, as discussed below. As a
result, we are not currently proposing any areas outside the
geographical area presently occupied by A. pumila because we have
determined that including only occupied areas in critical habitat is
sufficient for the conservation of the species. In San Diego County,
where the pattern of extirpated occurrences reflects a loss of
occurrences from each of the watersheds in which the species occurs
rather than a complete loss from those watersheds, the areas occupied
at the time of listing include the known historical range of the
species (CNDDB 2008). In Riverside County, the loss of an occurrence
near the Riverside Airport reflects a loss to the geographical extent
of the range in that county (Provance and Sanders 2001, p. 47).
We also reviewed available information that pertains to the habitat
requirements of this species, although A. pumila has not been well
studied and little is known about its habitat specificity,
characteristics, and breeding system. Additionally, data from different
information sources at times conflict, further complicating the task of
discerning the specific habitat requirements of the species. We used
numerous sources of information, such as materials and data included in
reports submitted to the Service during section 7 consultations and
other project reviews, and by biologists holding section 10(a)(1)(A)
recovery permits; research published in peer-reviewed articles and
presented in academic theses and agency reports; regional Geographic
Information System (GIS) coverages for area calculations and mapping;
and data collected in the field by Service biologists.
We are proposing to designate critical habitat in areas that we
determined were occupied by the species at the time of listing, and
that contain the PCEs in the quantity and spatial arrangement to
support life history functions essential to the conservation of the
species. This includes two areas occupied by occurrences detected after
Ambrosia pumila was listed. We have concluded that these areas were
occupied at the time the species was listed because individuals of
species with a clonal growth habit like A. pumila are usually long-
lived (Watkinson and White 1985, pp. 44-45; Tanner 2001, p. 1980). The
occurrence near Santa Gertrudis Creek was found during a survey for a
subtransmission line project in 2006 (AMEC 2006, p. 12). The occurrence
at the intersection of State Route 76 and Olive Hill Road was found
during a general survey for A. pumila in 2006 (CNDDB 2008). To our
knowledge, the areas had not been surveyed for A. pumila previously,
and we have no reason to believe the plant was imported or had
dispersed into these areas from other areas after A. pumila was listed.
The occurrences identified since listing likely were in existence for
many years and were only recently detected due to increased awareness
of this species.
We are also proposing to designate critical habitat in some areas
where A. pumila was thought to be extirpated or where, though extant,
A. pumila was not considered viable at the time of listing. We
conducted surveys of historical occurrences as part of the background
research for this proposed rule. We found one documented occurrence
area east of Lake Hodges in San Diego County that was thought to be
extirpated or nonviable because the occurrence had not been seen since
1999, and because records did not contain sufficient information to
locate the occurrence site. Our survey found this site does contain a
viable occurrence of A. pumila and meets the criteria set out in this
rule for A. pumila critical habitat. The site was located after the
species was listed and found to contain a large population of A.
pumila. We are not proposing to designate any areas outside the
geographical area occupied by the species at the time of listing, and
all of the areas we are proposing to designate are currently occupied
by the species. All units and subunits proposed contain the PCEs
believed to be essential to the conservation of this species.

Methods

As required by section 4(b)(1)(A) of the Act, we use the best
scientific and commercial data available in trying to determine areas
that contain the features that are essential to the conservation of
Ambrosia pumila. We used the best scientific data available to select
areas that we believe may possess those physical and biological
features essential to the conservation of the species, and that may
require special management considerations or protection.
After identifying the PCEs, we followed these steps to delineate
critical habitat:
(1) We identified areas occupied by Ambrosia pumila at the time of
listing as extant occurrences, where an occurrence is defined as an
occupied habitat area separated by 0.25 mi (0.40 km) or more from the
next nearest occupied habitat area.
(2) We determined that due to the lack of specific information
regarding the needs of the species, we are unable to identify specific
areas outside the geographical area occupied by the species at the time
it was listed that may be essential to the conservation of the species.

[[Page 44246]]

(3) We removed all areas where the species occurs in habitat of low
quality for growth and propagation (such as pavement areas or cracks
within paved areas). Although occupied, we believe these occurrences
are not capable of providing for the full life-history requirements of
this species and are not likely to contribute to its long-term
conservation; therefore, we did not consider these locations as
containing essential features as habitat and did not include them in
critical habitat.
(4) To define an outer boundary for each patch that captures the
existing underground rhizome system (which extends beyond the visible
aerial stems of plants within each occurrence), we added the average
distance between the visible (aerial stems) portions of each Ambrosia
pumila patch and the next nearest patch to the limits of the visible
portion of each patch. Using GIS data, we found the average distance
between clusters of stems in adjacent patches to be approximately 1,181
ft (260 m), and we added this distance to the visible outer limit of
each occurrence to delineate the presumed expanse of the occurrence
that also includes the underground rhizomes.
(5) We removed any area within the outer boundary of an occurrence
where habitat type was not grassland, ruderal, or coastal sage scrub.
We describe how we implemented each of the steps above in detail
below.
(1) We identified all occurrences of Ambrosia pumila--those known
to exist at the time of listing and those detected since listing. We
compiled data from the following sources to create our database of A.
pumila occurrences: (1) Data used in the 2002 listing rule for A.
pumila (67 FR 44372; July 2, 2002); (2) the California Natural
Diversity Database occurrence data report for A. pumila and
accompanying GIS records (CNDDB 2008, pp. 1-49); (3) the data from the
Consortium of California Herbaria and accompanying Berkeley Mapper GIS
records (Consortium of California Herbaria 2008, pp. 1-5); (4) the
Western Riverside County Multiple Species Habitat Conservation Plan
(Western Riverside County MSHCP) species GIS database; and (5) the
Carlsbad Fish and Wildlife Office's internal species GIS database,
which includes the species data used for the San Diego Multiple Species
Conservation Program (MSCP) and the San Diego Multiple Habitat
Conservation Plan (MHCP), reports from section 7 consultations, and
Service observations of A. pumila (CFWO internal species GIS database).
As discussed in detail earlier in this section, we consider all extant
occurrences to have been in existence at the time of listing. We used
these data to delineate GIS polygons around Ambrosia pumila
occurrences.
We reviewed the data that we compiled to ensure its accuracy. We
checked each data point in our database to ensure that it represented a
site documented by a herbarium voucher or observation of Ambrosia
pumila and was not a duplicate voucher or observation of another
occurrence in the database. Duplicates were removed from our database.
Secondly, we checked each data point to ensure that it was correctly
mapped. Data points that did not match the description for the original
herbarium collection or observation were remapped in the correct
location, if possible. We removed observations where the location could
not be determined from available data or site visits.
We then determined which areas are currently occupied. For areas
where we have past occupancy data for Ambrosia pumila, we assumed the
area remains occupied unless: (1) Three or more surveys for the species
did not find A. pumila; (2) the site was significantly disturbed (for
example, converted to development) since the last observation of the
species at that location; or (3) specific location information for the
site was lacking, and field surveys carried out in conjunction with
this proposed critical habitat determination could not locate the
occurrence.
(2) We determined that there are no specific areas outside the
geographical area occupied by the species at the time it was listed
that are essential to the conservation of the species. Information
found during the Service's research in connection with this proposed
action indicated that the geographical area occupied by the species at
the time it was listed provides sufficient resources for the
conservation of the species. We do not have sufficient information
regarding the specific needs of the species to determine if any
unoccupied areas are essential for the conservation of the species.
(3) We removed areas where Ambrosia pumila occurs in habitat of low
quality for growth and propagation (such as pavement areas or cracks
within paved areas). Although occupied, we did not consider these
locations for critical habitat, as these occurrences are not likely to
contribute to the long-term conservation of the species. We made this
determination using site descriptions in the California Natural
Diversity Database, talking to Service biologists, other researchers,
and land managers familiar with the areas in question, and visiting and
evaluating sites in person.
(4) We estimated the distance that the root system of an occurrence
likely extends beyond the aboveground extent of the occurrence by
measuring the distance of each GIS polygon representing an Ambrosia
pumila patch to the nearest neighboring patch. As mentioned above, an
occurrence is defined by CNDDB as an occupied habitat area separated by
0.25 mi (0.40 km) or more from next nearest occupied habitat area. A
patch is defined herein as a distinct cluster of stems within an
occurrence. We estimated the average distance of underground rhizome
expansion beyond the aboveground aerial stems as 1,181 ft (260 m). We
expanded the outer boundary of the above-ground extent of each
occurrence by 1,181 ft (260 m) to account for the underground rhizome
system extending beyond the area occupied by visible stems. We believe
this method adequately captures the extent of individual occurrences.
(5) We removed any areas within the expanded outer boundary of an
occurrence where habitat type was not grassland, ruderal, or open areas
within coastal sage scrub habitat, using the habitat types assigned to
relevant areas in our GIS database, and personal observations of sites
by Service biologists and other researchers or land managers.
Based on the results of this methodology, we are proposing to
designate 7 units that include 8 subunits as critical habitat for
Ambrosia pumila. After applying the above criteria and methods, we
mapped the critical habitat unit boundaries at each of these seven
units as GIS polygons around known occurrences. Critical habitat
boundaries were delineated as polygons encompassing the extent of
habitat believed to contain the physical and biological features
essential to the conservation of the species that may require special
management considerations or protection.
When determining the proposed critical habitat boundaries, we made
every effort to avoid including developed areas such as lands occupied
by buildings, paved areas, and other structures that lack PCEs for
Ambrosia pumila. The scale of the maps we prepared under the parameters
for publication within the Code of Federal Regulations may not reflect
the exclusion of such developed areas. Any developed structures and the
land under them inadvertently left inside critical habitat boundaries
shown on the maps of this proposed critical habitat are excluded by
text in this rule and are not proposed for critical habitat
designation. Therefore, if the critical habitat is

[[Page 44247]]

finalized as proposed, Federal actions involving these lands would not
trigger section 7 consultation with respect to critical habitat and the
requirement of no adverse modification unless the specific actions
would affect the species or PCEs in adjacent critical habitat.
We are soliciting public comment for information that may assist us
in defining those physical and biological features essential to the
conservation of the species which may require special management
considerations or protection, or in identifying specific areas outside
the geographical area occupied by the species at the time it was listed
that may be essential to the conservation of the species (see questions
2 and 3 in the Public Comments section).

Proposed Critical Habitat Designation

We determined that approximately 802 ac (324 ha) meet our
definition of critical habitat for Ambrosia pumila, including lands
under Federal, State, other government, and private ownership. We are
proposing 7 units that include 8 subunits as critical habitat for A.
pumila. Table 1 identifies the approximate area of each proposed
critical habitat unit and subunit by landownership.

Table 1--Proposed critical habitat units for Ambrosia pumila.
Area estimates reflect all land within critical habitat unit boundaries.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Location (California Natural Federally Owned Land State or Local Government Owned Land Privately Owned Land Total Area
Diversity Database(CNDDB) ---------------------------------------------------------------------------------------------------------------------------------------------------------------
Occurrence Number) acres hectares acres hectares acres hectares acres hectares
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
RIVERSIDE COUNTY
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 1: Temescal Creek watershed -- -- 23.4 9.5 88.4 35.8 111.8 45.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1A. Alberhill (\*\) -- -- 23.4 9.5 18.0 7.3 41.4 16.8
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1B. Nichols Road (44) -- -- -- -- 70.4 28.5 70.4 28.5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 2: Skunk Hollow Vernal Pool -- -- -- -- 118.1 47.8 118.1 47.8
watershed (22)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 3: Santa Gertrudis Creek -- -- -- -- 32.5 13.2 32.5 13.2
watershed (55)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SUBTOTAL: -- -- 23.4 9.5 239.0 96.8 262.4 106.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SAN DIEGO COUNTY
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 4: San Luis Rey River -- -- 2.4 1.0 102.5 41.5 104.9 42.5
watershed
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4A. Calle de la Vuelta (43) -- -- -- -- 29.6 12.0 29.6 12.0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4B. Olive Hill Road (16) -- -- 0.3 0.1 34.8 14.1 35.0 14.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
4C. Jeffries Ranch (45) -- -- 2.2 0.9 38.1 15.4 40.3 16.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 5: San Dieguito River -- -- 15.8 6.4 5.3 2.2 21.2 8.6
watershed - Lake Hodges (14)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 6: San Diego River -- -- 171.5 69.4 26.4 10.7 197.8 80.1
watershed - Mission Trails
Regional Park (12)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 7: Sweetwater River 145.5 58.9 12.6 5.1 57.1 23.1 215.2 87.1
watershed
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
7A. Jamul Road (1) -- -- 2.5 1.0 36.4 14.7 38.9 15.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
7B. San Diego National Wildlife 117.6 47.6 -- -- 15.0 6.1 132.5 53.6
Refuge (48)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
7C. Steele Canyon Bridge (34) 27.9 11.3 10.1 4.1 5.8 2.3 43.7 17.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SUBTOTAL: 145.5 58.9 202.3 81.9 191.3 77.4 539.1 218.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
TOTAL 145.5 58.9 225.7 91.4 430.4 174.2 801.6 324.4
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\*\ Occurrence not entered in CNDDB.
\**\Values in this table may not sum due to rounding.

The areas we are proposing as critical habitat currently provide
all habitat components necessary to meet the primary biological needs
of Ambrosia pumila, as defined by the physical and biological features
essential to the conservation of the species. These areas constitute
our best assessment of areas determined to be occupied at the time of
listing that contain the PCEs for A. pumila that may require special
management considerations or protection. We are not proposing any
unoccupied areas or areas outside of the species' historical range
because we

[[Page 44248]]

determined that occupied lands within the species' historical range are
sufficient for the conservation of A. pumila. Each unit and subunit
includes suitable habitat that will allow for population growth and
growth of aerial stems from parts of the root system.
Presented below are brief descriptions of all subunits and reasons
why they meet the definition of critical habitat for Ambrosia pumila.
The subunits are listed in order geographically north to south and east
to west.

Unit 1: Temescal Creek Watershed

Unit 1 is located in western Riverside County and consists of two
subunits totaling approximately 23 ac (10 ha) of County-owned land, and
88 ac (36 ha) of private land, for a total of approximately 112 ac (45
ha) (values do not sum due to rounding).
Subunit 1A: Alberhill
Subunit 1A is located near Alberhill, north of Lake Elsinore and
just west of Interstate Highway 15 in Riverside County, California.
This subunit is near the northern base of Alberhill Mountain, east of
Lake Street, and south of Temescal Creek (also called Alberhill Creek).
Subunit 1A consists of approximately 23 ac (10 ha) of County owned
land, and 18 ac (7 ha) of privately owned land, for a total of
approximately 41 ac (17 ha). This subunit (along with subunit 1B)
represents the northernmost occurrence of this species, which is
geographically situated to assist this species expand its range
northward. Like all other extant occurrences, this subunit is also
essential to the conservation of this species because of its
contribution to the genetic diversity of the species (McGlaughlin and
Friar 2007, p. 329). This subunit was occupied at the time of listing
and remains occupied. Subunit 1A contains physical and biological
features that are essential to the conservation of A. pumila, including
sandy loam or clay soils located on an upper terrace of a water source,
which provide nutrients, moisture, and periodic flooding presumed
necessary for the plant's persistence (PCE 1); and ruderal habitat
type, which allows adequate sunlight and airflow for A. pumila (PCE 2).
The physical and biological features essential to the conservation of
the species in this subunit may require special management
considerations or protection to address threats from nonnative plant
species in situations where nonnative species are outcompeting A.
pumila for resources, and from human encroachment that occurs in the
area. The County-owned portions of Subunit 1A are conserved and are
being managed for the County by the Western Riverside County Regional
Conservation Authority in accordance with Western Riverside MSHCP
guidelines. Please see the ``Special Management Considerations or
Protection'' section of this proposed rule for a discussion of the
threats to A. pumila habitat and potential management considerations.
Subunit 1B: Nichols Road
Subunit 1B is located about 2.1 mi (3.5 km) southeast of Subunit 1A
(Alberhill), on the north and south sides of Nichols Road, in Riverside
County, California. This subunit is near the southeastern base of
Alberhill Mountain, just west of Durant Road and Temescal Creek.
Subunit 1B consists of approximately 70 ac (28 ha) of privately owned
land. This subunit was occupied at the time of listing and remains
occupied, and is essential to the conservation of this species because
this subunit (along with subunit 1A) represents the northernmost
occurrences of this species, which is geographically situated to
potentially assist this species expand its range northward. Like all
other extant occurrences, this subunit is also essential to the
conservation of this species because of its contribution to the genetic
diversity of the species (McGlaughlin and Friar 2007, p. 329). However,
due to impacts from unauthorized grading and disking, and a permitted
road realignment project, A. pumila within this subunit may be in
imminent danger of extirpation. Subunit 1B contains physical and
biological features that are essential to the conservation of Ambrosia
pumila, including sandy loam or clay soils located on an upper terrace
of a water source, which provide nutrients, moisture, and periodic
flooding presumed necessary for the plant's persistence (PCE 1), and
ruderal habitat type, which allows adequate sunlight and airflow for A.
pumila (PCE 2). The physical and biological features essential to the
conservation of the species in this subunit may require special
management considerations or protection to address threats from
nonnative plant species in situations where nonnative species are
outcompeting A. pumila for resources, and from activities (grading,
construction, human encroachment) that occur in the area. Please see
the ``Special Management Considerations or Protection'' section of this
proposed rule for a discussion of the threats to A. pumila habitat and
potential management considerations.

Unit 2: Skunk Hollow Vernal Pool Watershed

Unit 2 is located in the Barry Jones (Skunk Hollow) Wetland
Mitigation Bank in unincorporated Riverside County. The mitigation bank
is located east of the City of Murrieta and is loosely bounded by
Browning Street on the north, the edge of an unnamed canyon on the
east, Murrieta Hot Springs Road on the south, and Pourroy Avenue on the
west. Unit 2 consists of approximately 118 ac (48 ha) of privately
owned land managed by Center for Natural Lands Management. This unit,
like all other extant occurrences, is essential to the conservation of
Ambrosia pumila because of its contribution to the genetic diversity of
the species (McGlaughlin and Friar 2007, p. 329). This unit was
occupied at the time of listing and remains occupied. Unit 2 contains
physical and biological features that are essential to the conservation
of A. pumila, including sandy loam or clay soils located on an upper
terrace of a water source, which provide nutrients, moisture, and
periodic flooding presumed necessary for the plant's persistence (PCE
1), and annual grassland habitat type, which allows adequate sunlight
and airflow for A. pumila (PCE 2). The physical and biological features
essential to the conservation of the species in this subunit require
continued special management considerations or protection to address
threats from nonnative plant species in situations where nonnative
species are outcompeting A. pumila for resources, and human
encroachment. The Center for Natural Lands Management is providing
needed management by maintaining fencing around the area to protect the
area from encroachment, and carrying out research to determine the best
method for control of nonnative plant species on-site. Please see the
``Special Management Considerations or Protection'' section of this
proposed rule for a discussion of the threats to A. pumila habitat and
potential management considerations.

Unit 3: Santa Gertrudis Creek Watershed (55)

Unit 3 is located about 1 mile (1.6 km) southwest of Unit 2, along
the San Diego Aqueduct, south of the intersection of Chandler and Suzi
Roads and north of Santa Gertrudis Creek in Riverside County. Unit 3
consists of approximately 32 ac (13 ha) of privately owned land. This
unit was occupied at the time of listing and remains occupied, and,
like all other extant

[[Page 44249]]

occurrences, is essential to the conservation of this species because
of its contribution to the genetic diversity of the species
(McGlaughlin and Friar 2007, p. 329). Unit 3 contains physical and
biological features that are essential to the conservation of A.
pumila, including sandy loam or clay soils located on an upper terrace
of a water source, which provide nutrients, moisture, and periodic
flooding presumed necessary for the plant's persistence (PCE 1), and
ruderal habitat type, which allows adequate sunlight and airflow for A.
pumila (PCE 2). The physical and biological features essential to the
conservation of the species in this unit may require special management
considerations or protection to address threats from nonnative plant
species in situations where nonnative species are outcompeting A.
pumila for resources, human encroachment, and utility maintenance
activities. Please see the ``Special Management Considerations or
Protection'' section of this proposed rule for a discussion of the
threats to A. pumila habitat and potential management considerations.

Unit 4: San Luis Rey River Watershed

Unit 4 is located in northwestern San Diego County and consists of
three subunits of approximately 2 ac (1 ha) of State or local
government owned land and approximately 103 ac (41 ha) of privately
owned land, for a total of approximately 105 ac (42 ha).
Subunit 4A: Calle de la Vuelta
Subunit 4A is located near junction of State Route 76 and Calle de
la Vuelta in unincorporated San Diego County. Subunit 4A consists of
approximately 30 ac (12 ha) of privately owned land. This subunit was
occupied at the time of listing and remains occupied, and, like all
other extant occurrences, is essential to the conservation of this
species because of its contribution to the genetic diversity of the
species (McGlaughlin and Friar 2007, p. 329). Subunit 4A contains
physical and biological features that are essential to the conservation
of Ambrosia pumila, including sandy loam or clay soils located on an
upper terrace of a water source, which provide nutrients, moisture, and
periodic flooding presumed necessary for the plant's persistence (PCE
1), and ruderal habitat type, which allows adequate sunlight and
airflow for A. pumila (PCE 2). The physical and biological features
essential to the conservation of the species in this subunit may
require special management considerations or protection to address
threats from nonnative plant species in situations where nonnative
species are outcompeting A. pumila for resources, human encroachment,
road maintenance activities, and future widening of State Route 76.
Please see the ``Special Management Considerations or Protection''
section of this proposed rule for a discussion of the threats to A.
pumila habitat and potential management considerations.
Subunit 4B: Olive Hill Road
Subunit 4B is located on the west side of State Route 76, south of
Olive Hill Road in unincorporated San Diego County. Subunit 4B consists
of approximately 0.3 ac (0.1 ha) of State or local government owned
land and approximately 35 ac (14 ha) of privately owned land, for a
total of approximately 35 ac (14 ha) (values do not sum due to
rounding). The occurrence in this subunit was considered extirpated at
the time of listing, but has since been found to be extant. Like all
other extant occurrences, it is essential to the conservation of this
species because of its contribution to the genetic diversity of the
species (McGlaughlin and Friar 2007, p. 329). Subunit 4B contains
physical and biological features that are essential to the conservation
of Ambrosia pumila, including sandy loam or clay soils located on an
upper terrace of a water source, which provide nutrients, moisture, and
periodic flooding presumed necessary for the plant's persistence (PCE
1), and grassland habitat type which allow adequate sunlight and
airflow for A. pumila (PCE 2). The physical and biological features
essential to the conservation of the species in this subunit may
require special management considerations or protection to address
threats from nonnative plant species in situations where nonnative
species are outcompeting A. pumila for resources, human encroachment,
road maintenance activities, and future widening of State Route 76.
Please see the ``Special Management Considerations or Protection''
section of this proposed rule for a discussion of the threats to A.
pumila habitat and potential management considerations.
Subunit 4C: Jeffries Ranch
Subunit 4C is located approximately 0.7 mile (1.1 km) southwest of
Bonsall Bridge, adjacent to the south side of State Route 76 in the
City of Oceanside, San Diego County. Subunit 4C consists of
approximately 2 ac (1 ha) of State or local government owned land and
approximately 38 ac (15 ha) of privately owned land, for a total of
approximately 40 ac (16 ha). This subunit was occupied at the time of
listing and remains occupied, and, like all other extant occurrences,
is essential to the conservation of this species because of its
contribution to the genetic diversity of the species (McGlaughlin and
Friar 2007, p. 329). Subunit 4C contains physical and biological
features that are essential to the conservation of Ambrosia pumila,
including sandy loam or clay soils located on an upper terrace of a
water source, which provide nutrients, moisture, and periodic flooding
presumed necessary for the plant's persistence (PCE 1), and nonnative
grassland habitat type, which allows adequate sunlight and airflow for
A. pumila (PCE 2). The physical and biological features essential to
the conservation of the species in this subunit may require special
management considerations or protection to address threats from
nonnative plant species in situations where nonnative species are
outcompeting A. pumila for resources, human encroachment, road and
utility maintenance activities, future widening of State Route 76, and
potential development. Please see the ``Special Management
Considerations or Protection'' section of this proposed rule for a
discussion of the threats to A. pumila habitat and potential management
considerations.

Unit 5: San Dieguito River Watershed--Lake Hodges

Unit 5 is located on the west side of Interstate 15, just north of
Lake Hodges and south of Via Rancho Parkway in San Diego County. Unit 5
consists of approximately 16 ac (6 ha) of local government owned land
and approximately 5 ac (2 ha) of privately owned land, for a total of
approximately 21 ac (9 ha) (values do not sum due to rounding). This
unit was occupied at the time of listing, remains occupied, and, like
all other extant occurrences, is essential to the conservation of this
species because of its contribution to the genetic diversity of the
species (McGlaughlin and Friar 2007, p. 329). Unit 5 contains physical
and biological features that are essential to the conservation of
Ambrosia pumila, including sandy loam or clay soils located on an upper
terrace of a water source, which provide nutrients, moisture, and
periodic flooding presumed necessary for the plant's persistence (PCE
1), and nonnative grassland habitat type, which allows adequate
sunlight and airflow for A. pumila (PCE 2). The physical and biological
features essential to the conservation of the species in this unit

[[Page 44250]]

may require special management considerations or protection to address
threats from nonnative plant species in situations where nonnative
species are outcompeting A. pumila for resources, human encroachment,
utility maintenance activities, and potential development. Please see
the ``Special Management Considerations or Protection'' section of this
proposed rule for a discussion of the threats to A. pumila habitat and
potential management considerations.

Unit 6: San Diego River Watershed--Mission Trails Regional Park

Unit 6 is located in Mission Trails Regional Park in the City of
San Diego. This unit includes three areas: (1) South of Old Mission Dam
and Father Junipero Serra Trail and west of Simeon Drive; (2) north of
Old Mission Dam and the San Diego River, and northwest of Simeon Drive;
and (3) immediately east of Kumeyaay Campground, north of Mission Gorge
Road, east of Bushy Hill Drive, and south of the San Diego River. Unit
6 consists of approximately 172 ac (69 ha) of land owned and managed by
the City of San Diego, and approximately 26 ac (11 ha) of privately
owned land, for a total of 198 ac (80 ha). This unit was occupied at
the time of listing and remains occupied, and like all other extant
occurrences, is essential to the conservation of this species because
of its contribution to the genetic diversity of the species
(McGlaughlin and Friar 2007, p. 329). Unit 6 contains physical and
biological features that are essential to the conservation of A.
pumila, including sandy loam or clay soils located on an upper terrace
of a water source, which provide nutrients, moisture, and periodic
flooding presumed necessary for the plant's persistence (PCE 1), and
nonnative grassland habitat type, which allows adequate sunlight and
airflow for A. pumila (PCE 2). The physical and biological features
essential to the conservation of the species in this unit may require
special management considerations or protection to address threats from
nonnative plant species in situations where nonnative species are
outcompeting A. pumila for resources, and human encroachment. Please
see the ``Special Management Considerations or Protection'' section of
this proposed rule for a discussion of the threats to A. pumila habitat
and potential management considerations.

Unit 7: Sweetwater River Watershed

Unit 7 is located in southwestern San Diego County and consists of
three subunits containing approximately 146 ac (60 ha) of federally
owned land (San Diego National Wildlife Refuge), approximately 13 ac (5
ha) of State or local government owned land, and approximately 57 ac
(23 ha) of privately owned land, for a total of approximately 215 ac
(87 ha) (values do not sum due to rounding).
Subunit 7A: Jamul Road
Subunit 7A is located southeast of the City of El Cajon at and near
junction of Jamul Road and Steele Canyon Road, on the north and south
sides of Jamul Road. Subunit 7A consists of approximately 2 ac (1 ha)
of State or local government owned land, and approximately 36 ac (15
ha) of privately owned land, for a total of approximately 39 ac (16 ha)
(values do not sum due to rounding). This subunit was occupied at the
time of listing and remains occupied, and, like all other extant
occurrences, is essential to the conservation of this species because
of its contribution to the genetic diversity of the species
(McGlaughlin and Friar 2007, p. 329). Subunit 7A contains physical and
biological features that are essential to the conservation of A.
pumila, including sandy loam or clay soils located on an upper terrace
of a water source, which provide nutrients, moisture, and periodic
flooding presumed necessary for the plant's persistence (PCE 1), and
nonnative grassland habitat type, which allows adequate sunlight and
airflow for A. pumila (PCE 2). The physical and biological features
essential to the conservation of the species in this subunit may
require special management considerations or protection to address
threats from nonnative plant species in situations where nonnative
species are outcompeting A. pumila for resources, alterations of site
hydrology, and off-highway-vehicle use. Please see the ``Special
Management Considerations or Protection'' section of this proposed rule
for a discussion of the threats to A. pumila habitat and potential
management considerations.
Subunit 7B: San Diego National Wildlife Refuge
Subunit 7B is located primarily on the San Diego National Wildlife
Refuge, south of Sweetwater River between Rancho San Diego Golf Course
and the hills to the south, and on the north and south sides of a dirt
trail adjoining the end of Par Four Drive in unincorporated San Diego
County. Subunit 7B consists of approximately 118 ac (48 ha) of Federal
land owned and managed by the Fish and Wildlife Service and
approximately 15 ac (6 ha) of privately owned land, for a total of
approximately 133 ac (54 ha). This subunit was occupied at the time of
listing and remains occupied, and is essential to the conservation of
this species because of its contribution to the genetic diversity of
the species (McGlaughlin and Friar 2007, p. 329). Subunit 7B contains
physical and biological features that are essential to the conservation
of A. pumila, including sandy loam or clay soils located on an upper
terrace of a water source, which provide nutrients, moisture, and
periodic flooding presumed necessary for the plant's persistence (PCE
1), and nonnative grassland habitat type, which allows adequate
sunlight and airflow for A. pumila (PCE 2). The physical and biological
features essential to the conservation of the species in this subunit
may require special management considerations or protection on
privately owned lands, and continued management and protection on
federally owned lands to address threats from nonnative plant species
in situations where nonnative species are outcompeting A. pumila for
resources, and human encroachment. Please see the ``Special Management
Considerations or Protection'' section of this proposed rule for a
discussion of the threats to A. pumila habitat and potential management
considerations.
Subunit 7C: Steele Canyon Bridge
Subunit 7C is located mainly on the east side of State Route 94 on
a slope between a concrete-lined ditch and a fence adjacent and
parallel to State Route 94, approximately 0.7 mile (1.1 km) southeast
of Subunit 7B, in unincorporated San Diego County. A small portion of
the subunit is located on the opposite side of State Route 94 just
south of Steele Canyon Bridge in a split-rail exclosure. Subunit 7C
consists of approximately 28 ac (11 ha) of federally owned land managed
by the Fish and Wildlife Service, approximately 10 ac (4 ha) of State
(California Department of Transportation) and local (County of San
Diego) government owned land, and approximately 6 ac (2 ha) of
privately owned land, for a total of approximately 44 ac (18 ha)
(values do not sum due to rounding). This subunit was occupied at the
time of listing and remains occupied. Like all other extant
occurrences, it is essential to the conservation of this species
because of its contribution to the genetic diversity of the species
(McGlaughlin and Friar 2007, p. 329). Subunit 7C contains physical and
biological features that are essential to the conservation of Ambrosia
pumila, including sandy loam or clay soils located on an upper terrace
of a water source, which provide

[[Page 44251]]

nutrients, moisture, and periodic flooding presumed necessary for the
plant's persistence (PCE 1), and nonnative grassland habitat type,
which allows adequate sunlight and airflow for A. pumila (PCE 2). The
physical and biological features essential to the conservation of the
species in this subunit may require special management considerations
or protection on State, local government, and privately owned lands,
and continued management and protection on federally owned lands to
address threats from nonnative plant species in situations where
nonnative species are outcompeting A. pumila for resources, and human
encroachment. Please see the ``Special Management Considerations or
Protection'' section of this proposed rule for a discussion of the
threats to A. pumila habitat and potential management considerations.

Effects of Critical Habitat Designation

Section 7 Consultation

Section 7(a)(2) of the Act requires Federal agencies, including the
Service, to ensure that actions they fund, authorize, or carry out are
not likely to destroy or adversely modify critical habitat. Decisions
by the 5th and 9th Circuit Courts of Appeal have invalidated our
definition of ``destruction or adverse modification'' (50 CFR 402.02)
(see Gifford Pinchot Task Force v. U.S. Fish and Wildlife Service, 378
F. 3d 1059 (9th Cir 2004) and Sierra Club v. U.S. Fish and Wildlife
Service et al., 245 F.3d 434, 442F (5th Cir 2001)), and we do not rely
on this regulatory definition when analyzing whether an action is
likely to destroy or adversely modify critical habitat. Under the
statutory provisions of the Act, we determine destruction or adverse
modification on the basis of whether, with implementation of the
proposed Federal action, the affected critical habitat would remain
functional (or retain the current ability for the PCEs to be
functionally established) to serve its intended conservation role for
the species (Service 2004a, p.3). Section 7(a)(2) of the Act requires
Federal agencies, including the Service, to evaluate their actions with
respect to any species that is endangered or threatened and with
respect to its critical habitat, if any is proposed or designated.
Regulations implementing 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
us 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. Conference reports provide
conservation recommendations to assist the agency in eliminating
conflicts that may be caused by the proposed action. We may issue a
formal conference report if requested by a Federal agency. Formal
conference reports on proposed critical habitat contain an opinion that
is prepared according to 50 CFR 402.14, as if critical habitat were
designated. We may adopt the formal conference report as the biological
opinion when the critical habitat is designated, if no substantial new
information or changes in the action alter the content of the opinion
(see 50 CFR 402.10(d)). The conservation recommendations in a
conference report or opinion are advisory.
If a species is listed or critical habitat is designated, 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 such a species or to destroy or adversely modify
its critical habitat. If a Federal action may affect a listed species
or its critical habitat, the responsible Federal agency (action agency)
must enter into consultation with us. As a result of this consultation,
we document compliance with the requirements of section 7(a)(2) through
our issuance of:
1. A concurrence letter for Federal actions that may affect, but
are not likely to adversely affect, listed species or critical habitat;
or
2. A biological opinion for Federal actions that may affect, and
are likely to adversely affect, listed species or critical habitat.
An exception to the concurrence process referred to in (1) above
occurs in consultations involving National Fire Plan projects. In 2004,
the U.S. Forest Service and the U.S. Bureau of Land Management (BLM)
reached agreements with the Service to streamline a portion of the
section 7 consultation process (BLM-ACA 2004, pp. 1-8; FS-ACA 2004, pp.
1-8). The agreements allow the U.S. Forest Service and the Bureau of
Land Management the opportunity to make ``not likely to adversely
affect'' determinations for projects implementing the National Fire
Plan. Such projects include prescribed fire, mechanical fuels
treatments (thinning and removal of fuels to prescribed objectives),
emergency stabilization, burned area rehabilitation, road maintenance
and operation activities, ecosystem restoration, and culvert
replacement actions. The U.S. Forest Service and the Bureau of Land
Management must insure staff is properly trained, and both agencies
must submit monitoring reports to the Service to determine if the
procedures are being implemented properly and effects on endangered
species and their habitats are being properly evaluated. As a result we
do not believe the alternative consultation processes being implemented
as a result of the National Fire Plan will differ significantly from
those consultations being conducted by the Service.
If we issue a biological opinion concluding that a project is
likely to jeopardize the continued existence of a listed species or
destroy and/or adversely modify critical habitat, we also provide
reasonable and prudent alternatives to the project, if any are
identifiable. We define ``reasonable and prudent alternatives'' at 50
CFR 402.02 as alternative actions identified during consultation that:
Can be implemented in a manner consistent with the
intended purpose of the action,
Can be implemented consistent with the scope of the
Federal agency's legal authority and jurisdiction,
Are economically and technologically feasible, and
Would, in the Director's opinion, avoid jeopardizing the
continued existence of the listed species or destroying or adversely
modifying critical habitat.
Reasonable and prudent alternatives can vary from slight project
modifications to extensive redesign or relocation of the project. Costs
associated with implementing a reasonable and prudent alternative are
similarly variable.
Regulations at 50 CFR 402.16 require Federal agencies to reinitiate
consultation on previously reviewed actions in instances where we have
listed a new species or subsequently designated critical habitat that
may be affected and the Federal agency has retained discretionary
involvement or control over the action (or the agency's discretionary
involvement or control is authorized by law). Consequently, Federal
agencies may sometimes need to request reinitiation of consultation
with us on actions for which formal consultation has been completed, if
those actions with discretionary involvement or control may affect
subsequently listed species or designated critical habitat.
Federal activities that may affect Ambrosia pumila or its
designated critical habitat require section 7 consultation under the
Act. Activities on State, Tribal, local, or private lands requiring a
Federal permit (such as a

[[Page 44252]]

permit from the U.S. Army Corps of Engineers under section 404 of the
Clean Water Act (33 U.S.C. 1251 et seq.) or a permit from us under
section 10 of the Act) or involving some other Federal action (such as
funding from the Federal Highway Administration, Federal Aviation
Administration, or the Federal Emergency Management Agency) are subject
to the section 7 consultation process. Federal actions not affecting
listed species or critical habitat, and actions on State, Tribal,
local, or private lands that are not federally funded, authorized, or
permitted, do not require section 7 consultations.

Application of the Adverse Modification Standard

The key factor related to the adverse modification determination is
whether, with implementation of the proposed Federal action, the
affected critical habitat would continue to serve its intended
conservation role for the species, or would retain its current ability
for the PCEs to be functionally established. Activities that may
destroy or adversely modify critical habitat are those that alter the
physical and biological features (PCEs) to an extent that appreciably
reduces the conservation value of critical habitat for Ambrosia pumila.
Generally, the conservation role of the A. pumila proposed critical
habitat units is to support the various life-history needs and provide
for the conservation of the species.
Section 4(b)(8) of the Act requires us to briefly evaluate and
describe in any proposed or final regulation that designates critical
habitat those activities involving a Federal action that may destroy or
adversely modify such habitat, or that may be affected by such
designation. Activities that may destroy or adversely modify critical
habitat may also jeopardize the continued existence of the species.
Activities that, when carried out, funded, or authorized by a
Federal agency, may adversely affect critical habitat and therefore
should result in consultation for Ambrosia pumila include actions that
would adversely affect the species' exposure to adequate moisture,
nutrients, sunlight, airflow, and periodic flooding. For example:
(1) Actions that would alter the configuration of the water sources
associated with Ambrosia pumila habitat or the upper terraces where A.
pumila habitat is found. Such activities could include, but are not
limited to, water impoundment, stream channelization, water diversion,
water withdrawal, and development activities. These activities could
alter the biological and physical features that provide the appropriate
habitat for A. pumila by altering or eliminating flooding events that
this species may rely on for dispersal, seed germination, and control
of competitors; reducing or increasing the availability of groundwater
that may result in a shift of habitat type to a community unsuitable
for A. pumila (shrub- or tree-dominated habitat, which would inhibit
exposure to needed sunlight and airflow); or causing increased erosion
that could remove soils appropriate for A. pumila growth.
(2) Activities that remove soils appropriate for A. pumila growth
such as plowing or grading, or activities that change the
characteristics of soils so that A. pumila growth is impeded, such as
soil compaction due to hiking and vehicle use also adversely affect
critical habitat.
We consider all of the units and subunits proposed as critical
habitat to contain features essential to the conservation of Ambrosia
pumila. All units are within the geographic range of the species, were
occupied at the time of listing, and are currently occupied by A.
pumila. To ensure that their actions do not jeopardize the continued
existence of A. pumila, Federal agencies already consult with us on
activities in areas currently occupied by A. pumila, or in unoccupied
areas if the species may be affected by their actions.

Exemptions

Application of Section 4(a)(3) of the Act

The Sikes Act Improvement Act of 1997 (Sikes Act) (16 U.S.C. 670a)
required each military installation that includes land and water
suitable for the conservation and management of natural resources to
complete an integrated natural resources management plan (INRMP) by
November 17, 2001. An INRMP integrates implementation of the military
mission for the installation with stewardship of the natural resources
found on the base. Each INRMP includes:
An assessment of the ecological needs on the installation