Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Astralagus brauntonii and Pentachaeta lyonii, 68982-69019 [05-22191]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 70, Number 217 (Thursday, November 10, 2005)]
[Proposed Rules]
[Pages 68982-69019]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-22191]



[[Page 68981]]

-----------------------------------------------------------------------

Part III





Department of the Interior





-----------------------------------------------------------------------



Fish and Wildlife Service



-----------------------------------------------------------------------



50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Designation of Critical 
Habitat for Astralagus brauntonii and Pentachaeta lyonii; Proposed Rule

Federal Register / Vol. 70, No. 217 / Thursday, November 10, 2005 / 
Proposed Rules

[[Page 68982]]


-----------------------------------------------------------------------

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AU51


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for Astralagus brauntonii and Pentachaeta lyonii

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
designate critical habitat for Astralagus brauntonii (Braunton's milk-
vetch) and Pentachaeta lyonii (Lyon's pentachaeta) pursuant to the 
Endangered Species Act of 1973, as amended (Act). For A. brauntonii, 
approximately 3,638 acres (ac) (1,471 hectares (ha)) fall within the 
boundaries of the proposed critical habitat designation. The proposed 
critical habitat for A. brauntonii is located in Ventura, Los Angeles, 
and Orange Counties, California. For P. lyonii, approximately 4,212 
acres (ac) (1,703 hectares (ha)) fall within the boundaries of the 
proposed critical habitat designation. The proposed critical habitat 
for P. lyonii is located in Ventura and Los Angeles Counties, 
California.

DATES: We will accept comments from all interested parties until 
January 9, 2006. We must receive requests for public hearings, in 
writing, at the address shown in the ADDRESSES section by December 27, 
2005.

ADDRESSES: If you wish to comment, you may submit your comments and 
materials concerning this proposal by any one of several methods:
    1. You may submit written comments and information to Diane Noda, 
Field Supervisor, U.S. Fish and Wildlife Service, Ventura Fish and 
Wildlife Office (VFWO), 2493 Portola Road, Suite B, Ventura, CA 93003.
    2. You may hand-deliver written comments to our VFWO, at the above 
address.
    3. You may send comments by electronic mail (e-mail) to 
fw82plantsch@fws.gov. For directions on how to submit electronic filing 
of comments, please see the ``Public Comments Solicited'' section.
    4. You may fax your comments to 805/644-3958.
    Comments and materials received, as well as supporting 
documentation used in the preparation of this proposed rule, will be 
available for public inspection, by appointment, during normal business 
hours at our VFWO at the above address.

FOR FURTHER INFORMATION CONTACT: Diane Noda, Field Supervisor, VFWO, at 
the above address (telephone 805/644-1766; facsimile 805/644-3958).

SUPPLEMENTARY INFORMATION:

Public Comments Solicited

    We intend that any final action resulting from this proposal will 
be as accurate and as effective as possible. Therefore, comments or 
suggestions from the public, other concerned governmental agencies, the 
scientific community, industry, or any other interested party 
concerning this proposed rule are hereby solicited. Comments 
particularly are sought concerning:
    (1) The reasons any habitat should or should not be determined to 
be critical habitat as provided by section 4 of the Act, including 
whether the benefit of designation will outweigh any threats to the 
species due to designation;
    (2) Specific information on the amount and distribution of 
Astralagus brauntonii and Pentachaeta lyonii habitat, and what areas 
that were occupied at the time of listing and that contain the features 
that are essential to the conservation of the species, should be 
included in the designations and why and what areas that were not 
occupied at the time of listing are essential to the conservation of 
the species and why;
    (3) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat;
    (4) Any foreseeable economic, national security, or other potential 
impacts resulting from the proposed designation and, in particular, any 
impacts on small entities;
    (5) Additional information on areas in Orange County which could be 
excluded in the final designation;
    (6) Whether our approach to designating critical habitat could be 
improved or modified in any way to provide for greater public 
participation and understanding, or to assist us in accommodating 
public concerns and comments.
    (7) Whether the following should be included as a primary 
constituent element (PCE) for Astragalus brauntonii: Plant communities 
in areas that are >=600 m in diameter, which is the minimum size needed 
to support associated insect pollinators (e.g., bees and wasps), and 
seed dispersers (e.g., insects and small mammals), and
    (8) Whether the following should be included as a PCE for 
Pentachaeta lyonii: Plant communities in areas that are >=600 m in 
diameter, which is the minimum size needed to support associated insect 
pollinators, specifically bees, wasps, and flies.
    If you wish to comment, you may submit your comments and materials 
concerning this proposal by any one of several methods (see ADDRESSES 
section). Please submit Internet comments to fw82plantsch@fws.gov in 
ASCII file format and avoid the use of special characters or any form 
of encryption. Please also include ``Attn: Braunton's milk-vetch and 
Lyon's pentachaeta'' in your e-mail subject header and your name and 
return address in the body of your message. If you do not receive a 
confirmation from the system that we have received your Internet 
message, contact us directly by calling our VFWO at phone number 805/
644-1766. Please note that the Internet address fw82plantsch@fws.gov 
will be closed out at the termination of the public comment period.
    Our practice is to make comments, including names and home 
addresses of respondents, available for public review during regular 
business hours. Individual respondents may request that we withhold 
their home addresses from the rulemaking record, which we will honor to 
the extent allowable by law. There also may be circumstances in which 
we would withhold from the rulemaking record a respondent's identity, 
as allowable by law. If you wish us to withhold your name and/or 
address, you must state this prominently at the beginning of your 
comment. However, we will not consider anonymous comments. We will make 
all submissions from organizations or businesses, and from individuals 
identifying themselves as representatives or officials of organizations 
or businesses, available for public inspection in their entirety. 
Comments and materials received will be available for public 
inspection, by appointment, during normal business hours at the above 
address.

Designation of Critical Habitat Provides Little Additional Protection 
to Species

    In 30 years of implementing the Act, the Service has found that the 
designation of statutory critical habitat provides little additional 
protection to most listed species, while consuming significant amounts 
of available conservation resources. The Service's present system for 
designating critical habitat has evolved since its original statutory 
prescription into a process that provides little real conservation 
benefit, is driven by litigation and the courts rather than biology, 
limits our ability to

[[Page 68983]]

fully evaluate the science involved, consumes enormous agency 
resources, and imposes huge social and economic costs. The Service 
believes that additional agency discretion would allow our focus to 
return to those actions that provide the greatest benefit to the 
species most in need of protection.

Role of Critical Habitat in Actual Practice of Administering and 
Implementing the Act

    While attention to and protection of habitat is paramount to 
successful conservation actions, we have consistently found that, in 
most circumstances, the designation of critical habitat is of little 
additional value for most listed species, yet it consumes large amounts 
of conservation resources. Sidle (1987) stated, ``Because the Act can 
protect species with and without critical habitat designation, critical 
habitat designation may be redundant to the other consultation 
requirements of section 7.'' Currently, only 470 species, or 37.5 
percent of the 1,253 listed species in the U.S. under the jurisdiction 
of the Service, have designated critical habitat.
    We address the habitat needs of all 1,253 listed species through 
conservation mechanisms such as listing, section 7 consultations, the 
Section 4 recovery planning process, the Section 9 protective 
prohibitions of unauthorized take, Section 6 funding to the States, and 
the Section 10 incidental take permit process. The Service believes 
that it is these measures that may make the difference for the 
conservation of many species.
    We note, however, that the August 6, 2004 Ninth Circuit judicial 
opinion, (Gifford Pinchot Task Force v. United States Fish and Wildlife 
Service) found our definition of adverse modification was invalid. In 
response to the decision, the Director has provided guidance to the 
Service based on the statutory language. In this rule, our analysis of 
the consequences and relative costs and benefits of the critical 
habitat designation is based on application of the statute consistent 
with the 9th Circuit's ruling and the Director's guidance.

Procedural and Resource Difficulties in Designating Critical Habitat

    We have been inundated with lawsuits for our failure to designate 
critical habitat, and we face a growing number of lawsuits challenging 
critical habitat determinations once they are made. These lawsuits have 
subjected the Service to an ever-increasing series of court orders and 
court-approved settlement agreements, compliance with which now 
consumes nearly the entire listing program budget. This leaves the 
Service with little ability to prioritize its activities to direct 
scarce listing resources to the listing program actions with the most 
biologically urgent species conservation needs.
    The consequence of the critical habitat litigation activity is that 
limited listing funds are used to defend active lawsuits, to respond to 
Notices of Intent (NOIs) to sue relative to critical habitat, and to 
comply with the growing number of adverse court orders. As a result, 
listing petition responses, the Service's own proposals to list 
critically imperiled species, and final listing determinations on 
existing proposals are all significantly delayed.
    The accelerated schedules of court ordered designations have left 
the Service with almost no ability to provide for adequate public 
participation or to ensure a defect-free rulemaking process before 
making decisions on listing and critical habitat proposals due to the 
risks associated with noncompliance with judicially-imposed deadlines. 
This in turn fosters a second round of litigation in which those who 
fear adverse impacts from critical habitat designations challenge those 
designations. The cycle of litigation appears endless, is very 
expensive, and in the final analysis provides relatively little 
additional protection to listed species.
    The costs resulting from the designation include legal costs, the 
cost of preparation and publication of the designation, the analysis of 
the economic effects and the cost of requesting and responding to 
public comment, and in some cases the costs of compliance with the 
National Environmental Policy Act (NEPA). None of these costs result in 
any benefit to the species that is not already afforded by the 
protections of the Act enumerated earlier, and they directly reduce the 
funds available for direct and tangible conservation actions.

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat in this proposed rule. For more 
information on the taxonomic history and description of Astralagus 
brauntonii and Pentachaeta lyonii, refer to the final listing rule 
published in the Federal Register on January 29, 1997 (62 FR 4172). It 
is our intent in this document to reiterate and discuss only those 
topics directly relevant to the development and designation of critical 
habitat or relevant information obtained since the final listing.
    Astragalus brauntonii is a short-lived perennial herb in the 
Fabaceae (Pea family); a thick taproot gives rise to stems that reach a 
height of 5 feet (ft) (1.5 meters (m)), making it one of the tallest 
species in the genus. It is associated with chaparral and coastal sage 
scrub plant communities and generally occurs along the tops of knolls 
ranging from 800 to 2,100 ft (244 to 640 m) in elevation (Fotheringham 
and Keeley 1998; CNDDB 2003; B. Landis, in litt. 2005). Common species 
associated with chaparral communities in this region of California are 
Adenostoma fasciculatum (chamise), Ceanothus spp. (California lilac), 
Arctostaphylos spp.(manzanita), Salvia spp. (sage), Eriogonum 
fasciculatum (California buckwheat), Malosma laurina (laurel sumac), 
Rhus ovata (sugar bush), and Yucca whipplei (yucca) (Hanes 1988). 
Common species associated with coastal sage scrub are Artemisia 
californica (California sagebrush), sages, California buckwheat, Rhus 
integrifolia (lemonade berry), Encelia californica (encelia), and 
Isocoma menziesii (goldenbush) (Mooney 1988). Chaparral and coastal 
sage scrub communities interdigitate with each other, with coastal sage 
scrub occurring on sites with less seasonal moisture availability, such 
as on lower slopes of the mountains facing the ocean interrupted by 
chaparral on higher, more mesic slopes, and then a reoccurrence of 
coastal sage scrub on the rain shadow lower slopes of the mountain 
interior (Mooney 1988). Both of these communities occur within a 
Mediterranean-type climate that is characterized by mild, wet winters 
and hot, dry summers. The chaparral shrubs in particular have developed 
low tissue water content and are thus prone to wildfires, particularly 
during the extreme conditions of the hot, dry ``Santa Ana'' winds 
(Beyers and Wakeman 2000). Under such conditions, fires may rapidly 
burn thousands of hectares of chaparral and coastal sage scrub. 
Patterns of fire occurrence for a period of 60 years in the Santa 
Monica Mountains reveal that, on average, most of the Santa Monica 
Mountains have burned three to 5 times in that period, with an average 
fire return interval ranging from 12.4 to 20.7 years (Radtke et al. 
1982). Many of the species that comprise the chaparral and coastal sage 
scrub communities are well adapted to regenerate after fire, either 
through the release of a dormant seed bank whose germination is 
stimulated by fire, or in other species, through

[[Page 68984]]

basal burl sprouting (Hanes 1971, Keeley and Zedler 1978).
    Like many other Astragalus species, A. brauntonii is self-fertile, 
and also produces seed through cross-pollination (Fotheringham and 
Keeley 1998). Insect visitors to A. brauntonii (i.e., likely 
pollinators) include megachilid bees (Family Megachilidae), and 
bumblebees (Family Apidae; Fotheringham and Keeley 1998). The resulting 
s eeds of A. brauntonii are enclosed in dense hairy pods, that may 
attach to the fur of mammals or automobile and bicycle tires, which may 
serve as a dispersal mechanism (B. Landis, pers. comm. 2005). Insects, 
rodents, and other small mammals are known to eat seeds and other parts 
of the plant (B. Landis, in litt. 2005), and this may also disperse 
seeds. The seeds require heat or physical scarification (breaking, 
scratching, or mechanically altering the seed coat) to germinate, and 
disturbances such as fire, and rainfall or flooding, which ``wash'' the 
seeds downhill are known to stimulate germination (Fotheringham and 
Keeley 1998). Human activities that disturb the soil such as mechanical 
scraping of soil (e.g., during road or trail maintenance) are also 
known to stimulate germination. The plants may produce a large number 
of seeds before dying back, depositing a seed ``bank'' in the soil that 
may remain dormant for many years until the next disturbance event. 
This aspect of their life history makes it difficult to determine the 
distribution and threats to the species. A portion of the habitat that 
is being proposed for designation in this rule was burned by wildfires 
during the month of October 2005; the spring season of 2006 will offer 
an opportunity to survey some of these areas for post-fire germination 
of A. brauntonii.
    A. brauntonii occurs in very small populations in five disjunct 
geographic areas in Ventura, Los Angeles, and Orange Counties, 
California. These areas include: (1) Simi Hills in eastern Ventura and 
western Los Angeles Counties; (2) eastern Santa Monica Mountains in Los 
Angeles County; (3) western Santa Monica Mountains near Pacific 
Palisades, Los Angeles County; (4) San Gabriel Mountains in Monrovia, 
Los Angeles County; and (5) Santa Ana Mountains in Orange County. At 
the time of listing in 1997, there were approximately 13 known 
occurrences of A. brauntonii in four geographic areas (areas 1, 3, 4, 
and 5). Currently, there are 20 known occurrences of A. brauntonii. 
Seven new occurrences were reported since the time of listing; six of 
these are in the Simi Hills (area 1), and one is in the eastern Santa 
Monica Mountains (area 2). The eastern Santa Monica Mountains 
occurrence, which represents a small range expansion for the species, 
was discovered along a ridgetop after a prescribed fire stimulated 
germination of dormant seeds, resulting in hundreds of plants. This 
population is approximately 8 miles (mi) (13 kilometers (km)) from the 
nearest known occurrence, which only consisted of one plant last seen 
in 1984 and is presumed to be extinct.
    The number of reported individual plants within each occurrence 
varies widely by year, with the largest number of individuals often 
reported soon after a disturbance and then declining until the next 
disturbance event. Land use activities that result in frequent 
disturbances, such as yearly road maintenance where plants occur, may 
contribute to the decline of populations by removing plants before they 
replenish the seed bank. Fire suppression may contribute to the decline 
of populations because they become crowded out by shrubs and nonnative 
plants. Other known threats to the species include cattle grazing and 
equestrian and foot traffic, which may result in trampling of plants.
    The most significant threat to the species, however, is direct loss 
of plants from urban development. Urban development also results in 
indirect effects to the species, including habitat fragmentation, which 
reduces gene flow between sites, reduction in insect pollinators, and 
increases in nonnative plants (Conservation Biology Institute 2000). 
All known occurrences are in the direct vicinity of urban areas. Six of 
these occur on private lands, eight on local agency lands (city and 
regional parks), four on State lands (Topanga State Park, Chino Hills 
State Park, and Coal Canyon Ecological Reserve), and two on Federal 
lands (Santa Monica Mountains National Recreation Area).
    Pentachaeta lyonii is an annual herb in the Asteraceae (Sunflower 
family). Its yellow flower heads bloom in the late spring (April to 
June) on stems that grow up to 48 centimeters (cm) (18 inches (in)) 
tall. It occurs in saddles between hills, on the tops of small knolls, 
or in flat areas at the base of slopes at elevations ranging from 280 
to 2,060 ft (85 to 628 m) (Fotheringham and Keeley 1998, CNDDB 2003). 
It occurs within pocket grasslands underlain by clay soils that mosaic 
with chaparral and coastal sage scrub communities that are fire-
adapted, although seeds do not require fire-related cues (such as heat, 
smoke, and charates) to germinate (Keeley and Baer-Keeley 1992, Keeley 
1995). The chaparral and coastal sage scrub communities are similar to 
those described above for Astragalus brauntonii. The pocket grasslands 
are comprised of native and nonnative grasses including Nassella 
pulchra (purple needlegrass), Avena spp. (wild oat), and Bromus spp. 
(bromes); and herbs such as Brassica spp. (mustard), Erodium spp. 
(filaree), Stylocline spp. (nest straw), and Plantago erecta 
(plantain).
    Pentachaeta lyonii is self-incompatible, meaning that it is 
dependent on cross-pollination for effective seed set (Fotheringham and 
Keeley 1998). Known pollinators of P. lyonii include digger bees 
(Family Apidae), andrenid bees (Andrena sp.), and megachilid bees 
(Ashmeadiella californica californica); (Fotheringham and Keeley 1998, 
Braker and Verhoeven 1998). The resulting single-seeded fruits have 
deciduous pappus which would limit their dispersal by wind; however, 
the fruits most likely are attractive to small mammals which could 
disperse them through caching.
    P. lyonii only occurs in the Santa Monica Mountains in eastern 
Ventura and western Los Angeles Counties and in the western Simi Hills 
in Ventura County. Based on historical records, it once occurred on the 
Palos Verdes Peninsula and on Santa Catalina Island; the species has 
not been seen at these locations since 1910 and 1855, respectively, and 
is assumed to be extirpated. At the time of listing in 1997, there were 
29 known occurrences of P. lyonii (62 FR 4172). Four of these are 
reported to have been extirpated since the time of listing, although 
the habitat remains (CNDDB 2005). Five new occurrences were reported 
since the time of listing; four of these are in the Santa Monica 
Mountains and one is in the western Simi Hills along Montclef Ridge. 
Currently, there are 30 known occurrences of P. lyonii, 21 of these are 
on private lands, eight on local agency lands (i.e., city and regional 
parks and a water district), and one on Federal lands (Santa Monica 
Mountains National Recreation Area).
    Alteration and destruction of habitat and direct removal of plants 
resulting from urban development remain the greatest threats to P. 
lyonii. Indirect effects of urban development include habitat 
fragmentation, which reduces gene flow between sites, reduction in 
insect pollinators, and changes to the structure and composition of 
pocket grassland communities that displace P. lyonii (i.e., 
introduction of competitive weeds, changes in local hydrology, and 
increased gopher activity) (Conservation Biology Institute 2000). Most 
of the known occurrences are in the direct

[[Page 68985]]

vicinity of urban areas, and the majority of plants occur on private 
lands.

Previous Federal Actions

    For more information on previous Federal actions concerning A. 
brauntonii and P. lyonii, refer to the final listing rule published in 
the Federal Register on January 29, 1997 (62 FR 4172). At the time of 
listing, we found the designation of critical habitat for both species 
to be not prudent. In September 1999, we published a recovery plan for 
A. brauntonii and P. lyonii (USFWS 1999). On January 27, 2003, our 
decision not to designate critical habitat for A. brauntonii and P. 
lyonii was challenged in Center for Biological Diversity v. Norton 
(Case No. 03-CV-0198-IEG (S.D.Cal.). On July 28, 2003, the Court 
entered a settlement agreement, in which the Service agreed to submit 
for publication a proposal to withdraw the existing ``not prudent'' 
determination together with a new proposed critical habitat 
determination for both species by November 1, 2005.

Prudency Determination

    Section 4(a)(3) of the Act and its implementing regulations (50 CFR 
424.12) require that, to the maximum extent prudent and determinable, 
we designate critical habitat at the time a species is listed as 
endangered or threatened. Our regulations at 50 CFR 424.12(a)(1) state 
that the designation of critical habitat is not prudent when one or 
both of the following situations exist: (1) the species is threatened 
by taking or other activity and the identification of critical habitat 
can be expected to increase the degree of threat to the species or (2) 
such designation of critical habitat would not be beneficial to the 
species. In our January 29, 1997, final rule (62 FR 4172), we 
determined that designation of critical habitat for A. brauntonii and 
P. lyonii was not prudent based on the first reason. Specifically, we 
stated that publication of precise maps and descriptions of critical 
habitat would make these plants more vulnerable to incidents of 
vandalism which could contribute to the decline of the species; 
therefore, such designation would provide little conservation benefit 
over that provided by listing.
    In addition, for A. brauntonii, we stated that designation of 
critical habitat could lead to overcollection by curiosity seekers as a 
result of increased publicity, especially because its striking 
appearance makes it vulnerable to casual collection. However, in the 
past few years, several of our determinations that the designation of 
critical habitat would not be prudent have been overturned by court 
decisions. For example, in Conservation Council for Hawaii v. Babbitt, 
the United States District Court for the District of Hawaii ruled that 
the Service could not rely on the ``increased threat'' rationale for a 
``not prudent'' determination without specific evidence of the threat 
to the species at issue (2 F. Supp. 2d 1280 [D. Hawaii 1998]). 
Additionally, in Natural Resources Defense Council v. U.S. Department 
of the Interior, the United States Court of Appeals for the Ninth 
Circuit ruled that the Service must balance, in order to invoke the 
``increased threat rationale,'' the threat against the benefit to the 
species of designating critical habitat (113 F. 3d 1121, 1125 [9th Cir. 
1997]).
    We have reconsidered our evaluation of the threats posed by 
vandalism and overcollection in the prudency determination. Since the 
time of listing in 1997, we have gathered information indicating that 
populations of A. brauntonii and P. lyonii continue to be directly and 
indirectly affected by destruction and alteration of habitat due to 
residential development. However, we have no credible information that 
these two species have been threatened from vandalism and 
overcollection. Accordingly, we withdraw our previous determination 
that the designation of critical habitat is not prudent for A. 
brauntonii and P. lyonii. We determine that the designation of critical 
habitat is prudent for A. brauntonii and P. lyonii. At this time, we 
have sufficient information necessary to identify specific areas which 
contain features essential to the conservation of the two species and 
are therefore proposing critical habitat (see ``Methods'' sections 
below for a discussion of information used in our reevaluation).

Critical Habitat

    Critical habitat is defined in section 3 of the Act as--(i) the 
specific areas within the geographical area occupied by a species, at 
the time it is listed in accordance with the Act, on which are found 
those physical or biological features (I) that are essential to the 
conservation of the species and (II) which may require special 
management considerations or protection; and (ii) specific areas 
outside the geographical area occupied by a species at the time it is 
listed, upon a determination that such areas have features that are 
essential for the conservation of the species. ``Conservation'' means 
the use of all methods and procedures that are necessary to bring an 
endangered or a threatened species to the point at which listing under 
the Act is no longer necessary.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against destruction or adverse modification of 
critical habitat with regard to actions carried out, funded, or 
authorized by a Federal agency. Section 7 requires consultation on 
Federal actions that are likely to result in the destruction or adverse 
modification of 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 government or public access to private lands.
    To be included in a critical habitat designation, the habitat 
within the area occupied by the species at the time of listing must 
first have features that are ``essential to the conservation of the 
species.'' Critical habitat designations identify, to the extent known 
using the best scientific and commercial data available, habitat areas 
that provide necessary life cycle needs of the species (i.e., areas on 
which are found the PCEs, as defined at 50 CFR 424.12(b)).
    Habitat occupied at the time of listing may be included in critical 
habitat only if the essential features thereon may require special 
management or protection. Thus, we do not include areas where existing 
management is sufficient to conserve the species. (As discussed below, 
such areas may also be excluded from critical habitat pursuant to 
section 4(b)(2).) Accordingly, when the best available scientific and 
commercial data do not demonstrate that the conservation needs of the 
species so require, we will not designate critical habitat in areas 
outside the geographical area occupied by the species at the time of 
listing. An area currently occupied by the species but that was not 
known to be occupied at the time of listing will likely have features 
that are essential to the conservation of the species and, therefore, 
will be included in the critical habitat designation.
    The Service's Policy on Information Standards Under the Endangered 
Species Act, published in the Federal Register on July 1, 1994 (59 FR 
34271), and Section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658) 
and the associated Information Quality Guidelines issued by the 
Service, provide criteria, establish procedures, and provide guidance 
to ensure that decisions made by the Service represent the best 
scientific and commercial data available. They require Service 
biologists, to the extent consistent with the Act and with the use of 
the best

[[Page 68986]]

scientific and commercial data available, to use primary and original 
sources of information as the basis for recommendations to designate 
critical habitat. When determining which areas are critical habitat, a 
primary source of information is generally the listing package for the 
species. Additional information sources 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. All information is used in 
accordance with the provisions of Section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658) and the associated Information Quality Guidelines 
issued by the Service.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Habitat is often 
dynamic, and species may move from one area to another over time. 
Furthermore, we recognize that designation of critical habitat may not 
include all of the habitat areas that may eventually be determined to 
be necessary for the recovery of the species. For these reasons, 
critical habitat designations do not signal that habitat outside the 
designation is unimportant or may not be required for recovery.
    Areas that support populations, but are outside the critical 
habitat designation, will continue to be subject to conservation 
actions implemented under section 7(a)(1) of the Act and to the 
regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available information 
at the time of the 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, or 
other species conservation planning efforts if new information 
available to these planning efforts calls for a different outcome.

Methods

    As required by section 4(b)(1)(A) of the Act, we used the best 
scientific and commercial data available in determining areas that 
contain the features that are essential to the conservation of A. 
brauntonii and P. lyonii. We have also reviewed available information 
that pertains to the habitat requirements of these species. This 
includes information from Service documents, including the final rule 
listing these taxa as endangered (62 FR 4172; January 29, 1997) and the 
recovery plan (USFWS 1999); information from the California Natural 
Diversity Database (CNDDB 2003); data in reports submitted during 
section 7 consultations and by biologists holding section 10(a)(1)(A) 
recovery permits; recent biological surveys; regional Geographic 
Information Systems (GIS) coverages; information from research 
published in peer-reviewed articles and presented in agency reports; 
aerial photos; and discussions with botanical experts. We designated no 
areas outside the geographic area presently occupied by the species.
    We used agency and academic reports to describe the ecology, 
habitat, and pollination biology of A. brauntonii and other related 
Astragalus species (Carroll 1987; Karron 1987; Fotheringham and Keeley 
1998; Gathmann and Tscharntke 2002). We used agency and academic 
reports to describe the ecology, habitat, and pollination biology of P. 
lyonii (Belnap 1990; Keeley and Baer-Keeley 1992; Keeley 1995; Braker 
and Verhoeven 1998; Fotheringham and Keeley 1998; Gathmann and 
Tscharntke 2002).
    We also reviewed the criteria by which the Service identified in 
the final recovery plan that A. brauntonii and P. lyonii would be 
conserved to the point at which the protections of the Act are no 
longer necessary (Service 1999). The criteria for delisting A. 
brauntonii include: (1) full protection and management of all sites 
that were known at the time of listing with the primary intention of 
preserving the populations in perpetuity; (2) seed collected from all 
populations is stored at a certified Center for Plant conservation 
botanical garden; (3) reliable seed germination and propagation 
techniques for the species are understood; and (4) monitoring shows 
that populations are self-sustaining over a minimum of 15 years or 
longer.
    The criteria for delisting P. lyonii include: (1) Full protection 
and management of 20 populations of 10,000 individuals or more with the 
primary intention of preserving the populations in perpetuity; (2) 
monitoring shows that populations are self-sustaining over a minimum of 
15 years or longer; (3) seed collected from all populations is stored 
at a certified Center for Plant Conservation botanic garden; and (4) 
reliable seed germination and propagation techniques for the species 
are understood.

Primary Constituent Elements

    The Service below identifies those essential physical and 
biological features necessary to bring A. brauntonii and P. lyonii to 
the point where the protections of the Act are no longer necessary.
    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12, in determining which areas to propose as critical 
habitat, we are required to base critical habitat designations on the 
best scientific data available and to consider those physical and 
biological features (primary constituent elements (PCEs)) that are 
essential to the conservation of the species, and that may require 
special management considerations and protection. These include, but 
are not limited to: space for individual and population growth and for 
normal behavior; food, water, air, light, minerals, or other 
nutritional or physiological requirements; cover or shelter; sites for 
breeding, reproduction, and rearing (or development) of offspring; and 
habitats that are protected from disturbance or are representative of 
the historic geographical and ecological distribution of a species.
    The specific PCEs required for A. brauntonii and P. lyonii habitat 
are derived from the physical and biological features that are 
essential to the conservation of a species as described below.

Astragalus brauntonii

Space for Individual and Population Growth, Including Sites for 
Germination, Pollination, Reproduction, and Seed Bank
    Where a dormant seed bank is present, A. brauntonii establishes 
quickly after disturbance events that remove other plant competitors 
and stimulate dormant seeds to germinate (Fotheringham and Keeley 
1998). Individual plants have a lifespan of two to three years, 
although some individuals may live up to five years, and then plants 
may not be visible again until the next disturbance event (Fotheringham 
and Keeley 1998).
    Insect pollinators of A. brauntonii are polylectic, meaning that 
they utilize several plant species within an area (Karron 1987), and 
may need a variety of plants to sustain populations of pollinators. 
Insect visitors include megachilid bees and bumblebees (Fotheringham 
and Keeley 1998). Gathmann and Tscharntke (2002) determined that 
maximum foraging

[[Page 68987]]

distance of several species of solitary bees was positively correlated 
with body length. The body length of megachilid bees ranges 6-12 
millimeters (mm) (0.24-0.47 in). Based on the linear regression model 
calculated by Gathmann and Tscharntke (2002), the maximum foraging 
distance of megachilid bees is 150-600 m (492-1,968 ft). The body 
length of bumblebees (Bombus sp.) ranges 13-25 mm (0.51-0.98 in), 
giving them a maximum foraging distance of 600-1,200 m (1,968-3,937 ft) 
(Gathmann and Tscharntke 2002).
Areas That Provide the Basic Requirements for Growth (Such as Water, 
Light, and Minerals)
    A. brauntonii may be limited to carbonate limestone soils derived 
from marine substrates (Mistretta 1992, Fotheringham and Keeley 1998, 
Betsey Landis, California Native Plant Society, in litt. 2005). It 
occasionally occurs on non-carbonate soils at down-wash sites near 
other known occurrences, although survivorship of plants may be reduced 
on non-carbonate soils (Fotheringham and Keeley 1998; B. Landis, in 
litt. 2005).
    Habitat of A. brauntonii has been described as scrub dominated by 
chaparral with a high overall percentage (<80%) of vegetative cover, 
however, the species does not tolerate shading and is associated with 
bare ground directly around the plant (Carroll 1987, Fotheringham and 
Keeley 1998). Common species associated with chaparral communities in 
this region of California are chamise (Adenostoma fasciculatum), 
California lilacs (Ceanothus spp.), manzanitas (Arctostaphylos spp.), 
sages (Salvia spp.), California buckwheat (Eriogonum fasciculatum), 
laurel sumac (Malosma laurina), sugar bush (Rhus ovata), and yucca 
(Yucca whipplei) (Hanes 1988). Common species associated with coastal 
sage scrub are California sagebrush (Artemisia californica), sages, 
California buckwheat, lemonade berry (Rhus integrifolia), encelia 
(Encelia californica), and goldenbush (Isocoma menziesii) (Mooney 
1988). It may persist on sites where microsite conditions inhibit or 
are hostile to shrub growth, or it may be gradually crowded out by more 
robust and tough-woody chaparral plants until the next disturbance 
event that removes plant cover (Carroll 1987, Fotheringham and Keeley 
1998).
    Based on our current knowledge of the life history, biology, and 
ecology of the species and the requirements of the habitat to sustain 
the essential life history functions of the species, we have determined 
that the PCEs of critical habitat for A. brauntonii are:
    (1) Carbonate limestone soils derived from marine sediment;
    (2) Low proportion (<10%) of shrub cover directly around the plant; 
and
    (3) Periodic disturbances that stimulate seed germination (e.g., 
fire, flooding) and reduce vegetative cover.

Pentachaeta lyonii

Space for Individual and Population Growth, Including Sites for 
Germination, Pollination, Reproduction, and Seed Bank
    P. lyonii is an annual plant that may exhibit large fluctuations in 
population size between years (Keeley and Baer-Keeley 1992). Population 
boundaries are also known to exhibit annual fluctuations, although the 
plants may generally remain within core areas that contain suitable 
microsite characteristics (Keeley and Baer-Keeley 1992). The presence 
of deciduous pappus bristles on the seeds indicates that the plant does 
not exhibit long-distance dispersal by wind, as do many other species 
in this family, reducing the likelihood of colonization of new areas 
and contributing to the limited distribution (Keeley and Baer-Keeley 
1992; Fotheringham and Keeley 1998). P. lyonii seeds may persist in the 
soil during dry spells, although the species does not maintain a long-
term seed bank (Fotheringham and Keeley 1998) because the seeds are 
small and do not contain large reserves of endosperm (energy source) to 
support the embryo until later germination.
    P. lyonii is not capable of self-pollination, but is dependent upon 
insect pollinators for successful seed production (Fotheringham and 
Keeley 1998). Pollinators of P. lyonii include digger bees, andrenid 
bees, and megachilid bees (Braken and Verhoeven 1998; Fotheringham and 
Keeley 1998). These insect pollinators are polylectic, meaning that 
they utilize several plant species within an area (Braken and Verhoeven 
1998), and may need a variety of plants to sustain populations of 
pollinators. Based on the linear regression model calculated by 
Gathmann and Tscharntke (2002), the maximum foraging distance of digger 
bees (body length 13-19 mm; 0.51-0.75 in) is approximately 600 m (1,968 
ft), and the maximum foraging distance of megachilid bees (body length 
6-12 mm; 0.24-0.47 in) is 150-600 m (492-1,968 ft). The maximum 
foraging distance of andrenid bees is 260-500 m (853-1,640 ft) 
(Gathmann and Tscharntke 2002).
    Areas That Provide the Basic Requirements for Growth (Such as 
Water, Light, and Minerals)
    P. lyonii tends to occur on rocky clay soils of volcanic origin 
(Baier & Associates 1991; Impact Sciences 2003). It has been recorded 
in areas with a large percentage of bare ground (>60%), a low 
proportion of vegetative cover (<25%), and it does not compete well 
with dense annual grasses or shrubs (Keeley 1995, Fotheringham and 
Keeley 1998). P. lyonii will persist in stable populations without 
disturbance if site conditions such as exposed soils that exhibit a 
microbiotic crust (Belnap 1990) inhibit invasion by shrubs and annual 
grasses, or it may require periodic disturbances to remove plant 
competitors (Fotheringham and Keeley 1998). The chaparral and coastal 
sage plant communities are described in the background section of this 
rule. The pocket grasslands within these shrub communities that support 
P. lyonii are comprised of native and nonnative grasses, including 
purple needlegrass (Nassella pulchra), wild oat (Avena spp.), and 
bromes (Bromus spp.); as well as a variety of herbs (see Background 
section).
    Based on our current knowledge of the life history, biology, and 
ecology of the species and the requirements of the habitat to sustain 
the essential life history functions of the species, we have determined 
that the PCEs of P. lyonii are:
    (1) Clay soils of volcanic origin;
    (2) Exposed soils that exhibit a microbiotic crust which may 
inhibit invasion by other plant competitors; and
    (3) Low proportion of total vegetative cover (<25%).

Criteria Used To Identify Critical Habitat

    We are proposing to designate critical habitat on lands that were 
occupied at the time of listing and contain the PCEs that have features 
that are essential to the conservation of A. brauntonii and P. lyonii. 
In a few instances, we are also proposing to designate occupied areas 
that were identified after listing, but that we have determined to be 
essential to the conservation of A. brauntonii and P. lyonii.

Astragalus brauntonii

    The long-term probability of the conservation of A. brauntonii is 
dependent upon the protection of existing population sites and 
surrounding areas that may contain a dormant seed bank, and the 
maintenance of ecologic functions within and between sites. Important 
ecologic functions include connectivity

[[Page 68988]]

between populations within close geographic proximity to facilitate 
pollinator activity, habitat of sufficient size and quality to maintain 
pollinators and seed dispersers, and the ability to allow or manage for 
appropriate periodic ground disturbances in order to stimulate dormant 
seeds within the soil to germinate.
    All known occurrences of A. brauntonii were selected because they 
are essential to the conservation of the species. Plants only occur in 
very small populations in disjunct areas, making the species 
particularly vulnerable to extinction because a population that becomes 
extirpated is unlikely to reestablish from other areas.
    We used a multi-step process to map proposed critical habitat 
units. First, we mapped all CNDDB records of A. brauntonii in a GIS 
format. These data consist of polygons depicting the results of field 
surveys for A. brauntonii. Additional records from recent surveys that 
are not in the CNDDB database were also mapped in a GIS format. We then 
expanded the boundaries of these mapped locations outward from the edge 
of each population by a distance of 300 m (984 ft) to provide for 
pollinator habitat and support associated pollinator species. Studies 
by Steffan-Dewenter and Tscharnthke (1999) have shown that if 
pollinator habitat within 1,000 m (3,280 ft) of some host plants is 
eliminated, seed set of some plant species may be decreased by as much 
as 50 percent. Additional studies have shown that degradation of 
pollinator habitat is likely to have a negative effect on pollinator 
species (Jennersten 1988; Rathcke and Jules 1993). Using a distance of 
300 m (984 ft) around each population, the minimum distance from one 
edge of the proposed habitat to the other would be 600 m (1,968 ft). As 
discussed in the PCEs section, known pollinators of A. brauntonii 
include megachilid bees and bumblebees. Based on body length, foraging 
ranges are approximately 150-600 m (492-1,968 ft) for megachilid bees 
and 600-1,200 m (1,968-3,937 ft) for bumblebees (Gathmann and 
Tscharntke 2002). We chose 600 m (1,968 ft) as the minimum distance 
from one edge of the habitat to the other as necessary to support both 
megachilid bees and bumblebees because 600 m is the minimum foraging 
range for bumblebees, and megachilid bees also fall within this 
foraging range. Because A. brauntonii seeds can be dormant for long 
periods of time, this approach may also include areas where an unknown 
seed bank occurs.
    Then, we connected areas that were within 600 m (1,968 ft) of each 
other because it is the distance between populations that could be 
traversed by important insect pollinators. We did this to facilitate 
genetic exchange and connectivity between populations. Plant 
communities between these areas would also support insect pollinators 
and seed dispersers of A. brauntonii, and may also contain unknown A. 
brauntonii plants and/or a dormant seed bank.
    The proposed critical habitat is designed to provide sufficient 
habitat to maintain self-sustaining populations of A. brauntonii 
throughout its range and provide those habitat components that have 
features that are essential for the conservation of the species. These 
habitat components provide for: (1) individual and population growth, 
including sites for germination, pollination, reproduction, pollen and 
seed dispersal, and seed bank; (2) intervening areas that allow gene 
flow and provide connectivity between occupied areas; and (3) areas 
that provide basic requirements for growth, such as appropriate soil 
type and vegetative cover.

Pentachaeta lyonii

    The long-term probability of the conservation of P. lyonii is 
dependent upon the protection of existing population sites and 
surrounding areas, and the maintenance of ecologic functions such as 
connectivity between populations within close geographic proximity to 
facilitate pollinator activity. Extant occurrences not known to be 
occupied at the time of listing of P. lyonii were selected as essential 
to the conservation of the species because the plant exhibits large 
annual fluctuations in population size, and there is no evidence that 
it maintains a dormant seed bank, making it particularly vulnerable to 
extinction.
    We used a multi-step process to map proposed critical habitat 
units. First, we mapped all CNDDB records of P. lyonii in a GIS format. 
These data consist of polygons depicting the results of field surveys 
for P. lyonii. Additional records from recent surveys that are not in 
the CNDDB database were also mapped in a GIS format. We then expanded 
the boundaries of these mapped locations outward from the edge of each 
population by a distance of 300 m (984 ft) to provide for pollinator 
habitat and support associated pollinator species. Using a distance of 
300 m (984 ft) around each population, the minimum distance from one 
edge of the proposed habitat to the other would be 600 m (1,968 ft). As 
discussed in the PCEs section, known pollinators of P. lyonii include 
digger bees, megachilid bees and andrenid bees. Based on body length, 
foraging ranges are approximately 600 m (1,968 ft) for digger bees, 
150-600 m (492-1,968 ft) for megachilid bees and 260-500 m (853-1,640 
ft) for andrenid bees (Gathmann and Tscharntke 2002). We chose 600 m 
(1,968 ft) as the minimum distance from one edge of the habitat to the 
other as necessary to support all of the associated insect pollinators 
because 600 m is the foraging range for digger bees, and megachilid 
bees and andrenid bees also fall within this foraging range. Population 
boundaries are known to fluctuate, so this approach may also include 
areas into which populations could expand.
    Then, we connected areas that were within 600 m (1,968 ft) of each 
other because it is the distance between populations that could be 
traversed by important insect pollinators. We did this to facilitate 
genetic exchange and connectivity between populations. Plant 
communities between these areas would also support insect pollinators 
of P. lyonii, and may also contain unknown P. lyonii plants.
    The proposed critical habitat is designed to provide sufficient 
habitat to maintain self-sustaining populations of P. lyonii throughout 
its range and provide those habitat components that have features that 
are essential for the conservation of the species. These habitat 
components provide for: (1) Individual and population growth, including 
sites for germination, pollination, reproduction, pollen and seed 
dispersal, and seed bank; (2) intervening areas that allow gene flow 
and provide connectivity between occupied areas; and (3) areas that 
provide basic requirements for growth, such as appropriate soil type 
and vegetative cover.
    Section 10(a)(1)(B) of the Act authorizes us to issue permits for 
the take of listed species incidental to otherwise lawful activities. 
An incidental take permit application must be supported by a habitat 
conservation plan (HCP) that identifies conservation measures that the 
permittee agrees to implement for the species to minimize and mitigate 
the impacts of the requested incidental take. We often exclude non-
Federal public lands and private lands that are covered by an existing 
operative HCP and executed implementation agreement (IA) under section 
10(a)(1)(B) of the Act from designated critical habitat because the 
benefits of exclusion outweigh the benefits of inclusion as discussed 
in section 4(b)(2) of the Act. We are aware of some efforts to conserve 
habitat for these species. However, at this point in time, we are 
unaware of any completed HCPs that have been done within the

[[Page 68989]]

areas that we are proposing for critical habitat. Before completion of 
the final rule, however, we will evaluate any HCPs brought to our 
attention during the comment period.
    When determining proposed critical habitat boundaries, we made 
every effort to avoid proposing the designation of developed areas such 
as buildings, paved areas, boat ramps and other structures that lack 
PCEs for A. brauntonii and P. lyonii. Any such structures inadvertently 
left inside proposed critical habitat boundaries are not considered 
part of the proposed unit. This also applies to the land on which such 
structures sit directly. Therefore, Federal actions limited to these 
areas would not trigger section 7 consultations unless they affect the 
species and/or PCEs in adjacent critical habitat.

Special Management Considerations or Protections

    When designating critical habitat, we assess whether the areas 
determined to be occupied at the time of listing and which contain the 
PCEs may require special management considerations or protections. We 
have also considered how designation highlights habitat that needs 
special management consideration or protection.
    Many of the known occurrences of A. brauntonii and P. lyonii are 
threatened by direct and indirect effects from habitat fragmentation 
and loss resulting from urban development. Threats to A. brauntonii 
include road maintenance, weed control, and fire suppression, which 
could result in improper disturbance frequencies, competition from 
nonnative plant species, cattle grazing, and recreation activities such 
as off-road vehicle use and equestrian and foot traffic. Threats to P. 
lyonii include weed control, mowing, and discing associated with fire 
suppression activities, competition from nonnative plant species, 
cattle grazing, and recreation activities such as off-road vehicle use 
and equestrian and foot traffic. These threats may require special 
management.

Proposed Critical Habitat Designation

Astragalus brauntonii

    We are proposing six units as critical habitat for A. brauntonii. 
The critical habitat areas described below constitute our best 
assessment at this time of areas determined to be occupied at the time 
of listing, contain the PCEs and that may require special management, 
and those additional areas that were not occupied at the time of 
listing but were found to be essential to the conservation of A. 
brauntonii. The units proposed as critical habitat are listed in Table 
1 below:

                                           Table 1.--Critical Habitat Units Proposed for Astragalus brauntonii
                            [Area estimates reflect all land within critical habitat boundaries, acres (ac) (hectares (ha))]
--------------------------------------------------------------------------------------------------------------------------------------------------------
            Critical habitat unit and subunit                   Federal             State           Local agency         Private             Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unit 1: Northern Simi Hills (Ventura Co.)................        0 ac (0 ha)              0 (0)             10 (4)          461 (187)          471 (191)
    Unit 1a..............................................              0 (0)              0 (0)             10 (4)           186 (75)           196 (79)
    Unit 1b..............................................              0 (0)              0 (0)              0 (0)            80 (32)            80 (32)
    Unit 1c..............................................              0 (0)              0 (0)              0 (0)           118 (48)           118 (48)
    Unit 1d..............................................              0 (0)              0 (0)              0 (0)            77 (32)            77 (32)
Unit 2: Southern Simi Hills (Ventura and Los Angeles Co.)           211 (85)              0 (0)        386 (156.5)          531 (214)      1,128 (455.5)
    Unit 2a..............................................              0 (0)              0 (0)           235 (95)           217 (88)          452 (183)
    Unit 2b..............................................              0 (0)              0 (0)            1 (0.5)              0 (0)            1 (0.5)
    Unit 2c..............................................              0 (0)              0 (0)           150 (61)             23 (9)           173 (70)
    Unit 2d..............................................           121 (49)              0 (0)              0 (0)              0 (0)           121 (49)
    Unit 2e..............................................            90 (36)              0 (0)              0 (0)            67 (27)           157 (63)
    Unit 2f..............................................              0 (0)              0 (0)              0 (0)           224 (90)           224 (90)
Unit 3: Santa Monica Mountains (Los Angeles Co.).........           183 (74)              0 (0)              0 (0)            60 (24)           243 (98)
Unit 4: Pacific Palisades Unit (Los Angeles Co.).........              0 (0)          485 (196)              0 (0)            92 (37)          577 (233)
Unit 5: Monrovia (Los Angeles Co.).......................              0 (0)              0 (0)          267 (108)            64 (26)          331 (134)
Unit 6: Coal Canyon (Orange Co.).........................              0 (0)          632 (256)              0 (0)          257 (104)          889 (360)
                                                          --------------------
        Total............................................          394 (159)        1,117 (452)        663 (268.5)        1,465 (592)    3,639 (1,471.5)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We present brief descriptions of all units, and reasons why they 
have the features that are essential for the conservation of A. 
brauntonii, below.
Unit 1: Northern Simi Hills Unit
    This unit is located south of Simi Valley in the northern Simi 
Hills in Ventura County and consists of 10 ac (4 ha) of local agency 
land (Rancho Simi Parks and Recreation Department) and 460 ac (186 ha) 
of private lands. It is divided into four subunits mapped from 
occurrences, all of which were identified after the time of listing; 
they all occur within 1.5 mi (2.5 km) of each other. This unit, 
inclusive of the four subunits, is located within the same 
physiographic area (the Simi Hills) as Unit 2, which is comprised of 
sites that were known to support A. brauntonii at the time of listing. 
Unit 1 represents a slightly northward range expansion of the species 
(2.1 mi (3.3 km) to the north), which is essential because the entire 
range of the species should be included to prevent range collapse of 
the species. These subunits contain features that are essential to the 
conservation of the species, specifically habitat that provides the 
space for A. brauntonii to complete its life cycle, including 
germination, reproduction, and storage of a seed bank. All four 
subunits are now known to be occupied. Threats that may require special 
management in this unit include road maintenance, which could result in 
disturbances that are too frequent, preventing establishment or 
replenishment of the seed bank, or fire suppression, that could result 
in disturbances that are too infrequent and thereby does not allow the 
removal of the shrub cover that is preventing germination of new 
plants. Other threats which may require special management include 
invasion of nonnative plants

[[Page 68990]]

which could crowd out A. brauntonii, cattle grazing, and recreation 
activities such as equestrian and foot traffic, which could result in 
trampling of plants.
    Subunit 1a: This subunit consists of 10 ac (4 ha) of local agency 
land in Challenger Park owned by Rancho Simi Parks and Recreation 
Department and 186 ac (75 ha) of private land. It occurs along Bus 
Canyon. This subunit contains at least three of the PCEs (2, 3, and 4); 
it is unknown if it contains PCE 1. This subunit is essential because 
A. brauntonii is extremely limited in distribution and has a very small 
overall population size, making it necessary to include every known 
occurrence. This subunit supports a population as evidenced by three 
plants that were observed in three separate locations in 1998.
    Subunit 1b: This subunit consists of 80 ac (32 ha) of private land 
that may be threatened by urban development. It occurs near the end of 
Peter Place Road in Simi Valley, which is north of Bus Canyon at the 
edge of an urban development. This subunit contains at least three of 
the PCEs (2, 3, and 4); it is unknown if it contains PCE 1. This 
subunit is essential because A. brauntonii is extremely limited in 
distribution and has a very small overall population size, making it 
necessary to include every known occurrence. This subunit supports a 
population of at least three plants that were observed in 2000.
    Subunit 1c: This subunit consists of 118 ac (48 ha) of private land 
within dedicated open space managed by the Bridle Path Homeowner's 
Association. It occurs along a ridge between Bus Canyon and Runkel 
Canyon above a fire road. This subunit contains all four of the PCEs. 
This subunit is essential because A. brauntonii is extremely limited in 
distribution and has a very small overall population size, making it 
necessary to include every known occurrence. This subunit supports a 
population of approximately 66 plants observed in 2004.
    Subunit 1d: This subunit consists of 77 ac (32 ha) of private land 
owned by Rocketdyne. This subunits contains at least three of the PCEs 
(2, 3, and 4); it is unknown if it contains PCE 1. This subunit is 
essential because A. brauntonii is extremely limited in distribution 
and has a very small overall population size, making it necessary to 
include every known occurrence. This subunit supports a population of 
at least three plants found in a single location.
Unit 2: Southern Simi Hills Unit
    This unit is located along the southern Simi Hills in Ventura and 
Los Angeles Counties and consists of 211 ac (85 ha) of Federal lands, 
386 ac (156.5 ha) of local agency lands (Conejo Open Space Conservation 
Authority (COSCA), City of Thousand Oaks, and Rancho Simi Parks and 
Recreation Department), and 531 ac (214 ha) of private land. This unit 
is divided into six subunits mapped from records known at the time of 
listing and occurrences identified after listing. These subunits are 
all within 3.2 mi (5.2 km) of each other and occur along the southern 
perimeter of the geologic Chatsworth Formation. Overall, these subunits 
provide connectivity between several occurrences known at the time of 
listing, and represent the southernmost portion of the species' range 
within the Simi Hills. Threats that may require special management in 
this unit include road and trail maintenance that could result in 
disturbances that are too frequent, preventing establishment or 
replenishment of the seed bank, or fire suppression, which could result 
in disturbances that are too infrequent, preventing germination of new 
plants. Other threats which may require special management include 
invasion of shrubs and nonnative plants, which could crowd out A. 
brauntonii, edge effects from urban development, and recreation 
activities such as off-road vehicles and equestrian and foot traffic, 
which could result in trampling of plants.
    Subunit 2a: This subunit consists of 235 ac (95 ha) of local agency 
lands designated as open space in Oak Brook Regional Park and owned and 
managed by COSCA, and 217 ac (88 ha) of private land. It includes smal