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

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A06-9089

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** November 14, 2006
- **Citation:** 71 FR 66374

## Text

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 Astragalus brauntonii and Pentachaeta lyonii

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), are designating critical habitat for the
Astragalus 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 3,300 acres (ac) (1,337 hectares (ha)) fall within the boundaries of the critical habitat designation. The critical habitat for
A. brauntonii
is located in Ventura, Los Angeles, and Orange Counties, California. For
P. lyonii
, approximately 3,396 ac (1,372 ha) fall within the boundaries of the critical habitat designation. The critical habitat for
P. lyonii
is located in Ventura and Los Angeles Counties, California.

DATES:

This rule becomes effective on December 14, 2006.

ADDRESSES:

Comments and materials received, as well as supporting documentation used in the preparation of this final rule, are available for public inspection, by appointment, during normal business hours, in the branch of Endangered Species, at the Ventura Fish and Wildlife Office, 2493 Portola Road, Suite B, Ventura, CA 93003. The final rule, economic analysis, and map are also available on the Internet at
http://www.fws.gov/ventura.

FOR FURTHER INFORMATION CONTACT:

Diane Noda, Field Supervisor, Ventura Fish and Wildlife Office, at the address in
ADDRESSES
(telephone 805/644-1766; facsimile 805/644-3958). Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339, 7 days a week and 24 hours a day.

SUPPLEMENTARY INFORMATION:

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

Attention to and protection of habitat are paramount to successful conservation actions. The role that designation of critical habitat plays in protecting habitat of listed species, however, is often misunderstood. As discussed in more detail below in the discussion of exclusions under section 4(b)(2) of the Act, there are significant limitations on the regulatory effect of designation under section 7(a)(2) of the Act. In brief, (1) designation provides additional protection to habitat only where there is a federal nexus; (2) the protection is relevant only when, in the absence of designation, destruction or adverse modification of the critical habitat would in fact take place (in other words, other statutory or regulatory protections, policies, or other factors relevant to agency decision-making would not prevent the destruction or adverse modification); and (3) designation of critical habitat triggers the prohibition of destruction or adverse modification of that habitat, but it does not require specific actions to restore or improve habitat.

Currently, only 476 species, or 36 percent of the 1,311 listed species in the United States under the jurisdiction of the Service, have designated critical habitat. We address the habitat needs of all 1,311 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, the section 10 incidental take permit process, and cooperative, nonregulatory efforts with private landowners. The Service believes that it is these measures that may make the difference between extinction and survival for many species.

In considering exclusions of areas originally proposed for designation, we evaluated the benefits of designation in light of
Gifford Pinchot Task Force
v.
United States Fish and Wildlife Service, 378 F.3d 1059 (9th Cir 2004) (hereinafter Gifford Pinchot).
In that case, the Ninth Circuit invalidated the Service's regulation defining “destruction or adverse modification of critical habitat.” In response, on December 9, 2004, the Director issued guidance to be considered in making section 7 adverse modification determinations. This critical habitat designation does not use the invalidated regulation in our consideration of the benefits of including areas in this final designation. The Service will carefully manage future consultations that analyze impacts to designated critical habitat, particularly those that appear to be resulting in an adverse modification determination. Such consultations will be reviewed by the Regional Office prior to finalizing to ensure that an adequate analysis has been conducted that is informed by the Director's guidance.

On the other hand, to the extent that designation of critical habitat provides protection, that protection can come at significant social and economic cost. In addition, the mere administrative process of designation of critical habitat is expensive, time-consuming, and controversial. The current statutory framework of critical habitat, combined with past judicial interpretations of the statute, make critical habitat the subject of excessive litigation. As a result, critical habitat designations are driven by litigation and courts rather than biology, and made at a time and under a time frame that limits our ability to obtain and evaluate the scientific and other information required to make the designation most meaningful.

In light of these circumstances, 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.

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 limited ability to provide for 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, and is expensive, thus diverting resources from conservation actions that may provide relatively more benefit to imperiled 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; U.S.C. 4371 et seq.). These costs, which are not required for many other conservation actions, 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 rule. For more information on
Astragalus brauntonii
and
Pentachaeta lyonii,
refer to the proposed critical habitat published in the
Federal Register
on November 10, 2005 (70 FR 68982), and the final listing rule published on January 29, 1997 (62 FR 4172).

Previous Federal Actions

For more information concerning previous Federal actions concerning
Astragalus brauntonii
and
Pentachaeta lyonii
, refer to the proposed designation of critical habitat published in the
Federal Register
on November 10, 2005 (70 FR 68982). 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. On November 10, 2005, we published a proposed rule to designate approximately 3,638 ac (1,471 ha) of critical habitat in 6 units in Ventura, Los Angeles, and Orange Counties, California, for
A. brauntonii
, and approximately 4,212 ac (1,703 ha) of critical habitat in 7 units in Ventura and Los Angeles Counties, California for
P. lyonii
(70 FR 68982). On July 21, 2006, we published a notice announcing the availability of the draft economic analysis (DEA), and reopening of the public comment period (71 FR 41410). This comment period closed on August 21, 2006.

Summary of Comments and Recommendations

We requested written comments from the public on the proposed designation of critical habitat for
Astragalus brauntonii
and
Pentachaeta lyonii
in the proposed rule published on November 10, 2005 (70 FR 68982). We also contacted appropriate Federal, State, and local agencies; scientific organizations; and other interested parties and invited them to comment on the proposed rule. The initial comment period ended January 9, 2006. We published newspaper notices on July 6, 2006, in the Ventura County Star, Ventura, California; and in the Yorba Linda Star, Orange County, California, inviting public comment on the economic analysis and proposed critical habitat designation. We did not receive any requests for a public hearing.

During the comment period that opened on November 10, 2005, and closed on January 9, 2006, we received 10 comments directly addressing the proposed critical habitat designation: 5 from peer reviewers, 1 from a Federal agency, and 4 from organizations or individuals. During the comment period that opened on July 21, 2006, and closed on August 21, 2006, we received five comments directly addressing the proposed critical habitat designation and the draft economic analysis. Of these latter comments, one was from a Federal agency, one was from a State agency, and three were from organizations or individuals. Fourteen commenters supported the designation of critical habitat for
Astragalus brauntonii
and
Pentachaeta lyonii
, and one commenter did not express support or opposition to the designation but requested that the lands under their ownership be excluded from the designation of critical habitat under section 4(b)(2) of the Act. All comments and new information relating to the proposed critical habitat designation for
A. brauntonii
and
P. lyonii
are addressed in the following summary and incorporated into the final rule as appropriate.

Peer Review

In accordance with our policy published on July 1, 1994 (59 FR 34270), we solicited expert opinions from seven knowledgeable individuals with scientific expertise that included familiarity with the species, the geographic region in which the species occurs, and conservation biology principles. We received responses from five of the peer reviewers. The peer reviewers generally concurred with our methods and conclusions and provided additional information, clarifications, and suggestions to improve the final critical habitat rule. Peer reviewer comments are addressed in the following summary and incorporated into the final rule as appropriate.

We reviewed all comments received from the peer reviewers and the public for substantive issues and new information regarding critical habitat for
Astragalus brauntonii
and
Pentachaeta lyonii
, and address them in the following summary.

Peer Reviewer Comments

1.
Comment:
A peer reviewer disagreed with our assertion that fire suppression was a threat to
Astragalus brauntonii
and
Pentachaeta lyonii.
He stated that despite efforts to suppress fires in coastal southern California, the present frequency of fires, which is every 15 years or less, is substantially higher than historically, which is thought to be every 50 to 100 years. This current fire frequency has resulted in displacing native shrubs with non-native grasses that are competitively superior to
A. brauntonii
and
P. lyonii.
Therefore, he recommended that management of critical habitat areas emphasize the need for preventing excessive fires.

Our Response:
We agree that excessive fires should be prevented in critical habitat areas. We note that
Astragalus brauntonii
responds favorably to fire because it triggers germination of dormant seeds. However, if fires are too frequent, this benefit may be outweighed by the risk of conversion to non-native grasslands. We recognize that the long dormant period for seeds suggests that frequent fires are not necessary to ensure persistence, and thus frequent fires should not be encouraged. Instead, the management goal should be to maintain those conditions to which the species is adapted. Contrary to the reviewer's assertion, we did not list fire suppression as a threat to
Pentachaeta lyonii.
Invasion of non-native plants and annual grasses is a major threat to both species, and therefore, excessive fires should be prevented in critical habitat for
both species.
We have removed fire suppression as a threat to
A. brauntonii
in the final designation.

2.
Comment:
A peer reviewer disagreed with the Service's statement that “critical habitat provides relatively little additional protection to listed species,” because designation of critical habitat includes information about the primary constituent elements the species needs for persistence and

recovery. This information can be used by Federal and non-Federal agencies to develop a basic landscape scale long-term conservation strategy for the species.

Our Response:
The section referenced by the reviewer is intended to be a general statement regarding our position on the designation of critical habitat. As discussed in the preamble of this and other critical habitat designation rules, we believe that, in most cases, conservation mechanisms provided through section 7, the section 4 recovery planning process, the section 9 protective prohibitions of unauthorized take, section 6 funding to the States, the section 10 incidental take permit process, and cooperative programs with private and public landowners and Tribes provide greater incentives and conservation benefits than does the designation of critical habitat. Furthermore, while we agree critical habitat designations include species specific information that can be used by Federal and non-Federal agencies to develop a basic landscape scale long-term conservation strategy for a species, agencies may obtain similar types of information from other Service documents, such as species recovery plans.

3.
Comment:
A peer reviewer commented that the proposed critical habitat rule did not discuss the Incidental Take permit for
Pentachaeta lyonii
pursuant to Fish and Game Code Section 1081 that is currently being processed for the Lake Sherwood Area Plan in Ventura County. The peer reviewer stated that most of the western portion of Unit 3c is addressed in the plan.

Our Response:
We are aware of the State of California's pending Incidental Take permit for the Lake Sherwood Area Plan. However, as of this final designation, the plan is not finished and thus has not yet been approved. Therefore, we did not consider the potential impacts of the proposed activities on
Pentachaeta lyonii
or critical habitat within the Lake Sherwood Area Plan for this designation.

4.
Comment:
A peer reviewer stated that we did not include in our records a location of
Astragalus brauntonii
that occurs on the “old Ahmanson property.”

Our Response:
The reviewer is referring to occurrence number 29 in the California Natural Diversity Database (CNDDB) record for
Astragalus brauntonii.
The exact location of this occurrence is not known. After careful review and inquiries to several individuals who are familiar with the occurrences for this species, we have concluded that this occurrence is probably incorrect and may not exist. We welcome any further information about this occurrence.

5.
Comment:
A peer reviewer stated that the “historic Stunt Ranch site” should be included for recovery purposes for potential reintroduction. The reviewer is referring to occurrence number 3 in the CNDDB database record for
Pentachaeta lyonii.

Our Response:
We did not include this occurrence because it currently does not appear to be suitable habitat for
Pentachaeta lyonii.
The species has not been present on the site since it burned in 1993. The soil in that area has been heavily disturbed by gophers, and this has made the area very favorable for non-native annual grasses. Despite the fact that this occurrence was not included in critical habitat, we recognize that there may be reintroduction potential for this site, and would consider this a valid recovery effort for the species.

6.
Comment:
A peer reviewer thought that the designation of critical habitat for
Astragalus brauntonii
should be postponed until the portions of proposed critical habitat that were burned by a wildfire in 2005 (subunits 1a-1d and subunits 2a-2f) could be surveyed. The fires may have stimulated dormant seeds of
A. brauntonii
in areas where the plant was not known to occur. The purpose of these surveys would be to determine if there are additional areas that contain
A. brauntonii
for inclusion into critical habitat.

Our Response:
We were unable to postpone designation of critical habitat to wait for the results of post-fire surveys because a July 28, 2003, settlement agreement and resulting court order mandated that we propose critical habitat by November 1, 2005, and finalize the critical habitat designation by November 1, 2006. However, we did fund post-fire surveys for
Astragalus brauntonii
in those areas that were burned. The results of those surveys revealed several new locations of
A. brauntonii
outside of proposed critical habitat. One location was found along a firebreak extending up to 2,297 feet (ft) (700 meters (m)) from subunit 2a in Oakbrook Regional Park, and at least four new locations were found between subunits 2d and 2e. These locations are within areas similar in habitat, and within the known distribution of the species. This highlights the difficulty in determining every occurrence of the species because the locations of dormant seeds may be unknown until a disturbance occurs. However critical habitat does not reflect every population or occurrence of
A. brauntonii.
We are designating habitat that we have determined contains the physical and biological features essential to the conservation of the species arranged in the quantity and spatial characteristics necessary for conservation (see section titled “Critical Habitat” below for more information on the determination of critical habitat).

7.
Comment:
A peer reviewer thought that PCE 1 for
Astragalus brauntonii
, which was “carbonate limestone soils derived from marine sediment,” was not the best description of the soil type associated with the plant. A recent study in which soil samples were taken at most locations of
A. brauntonii
revealed that the plant occurs in areas with calcium carbonate soils (a broader range of soils), and not necessarily where soils are derived from limestone (Landis 2005). The reviewer suggested that the original PCE could lead researchers to only look for
A. brauntonii
in soils that are obviously derived from limestone.

Our Response:
We have changed this PCE by removing the reference to limestone soils and adding calcium carbonate to the soils description. This change is also reflected in “Areas that Provide the Basic Requirements for Growth (Such as Water, Light, and Minerals).”

8.
Comment:
A peer reviewer commented that he is aware of occurrences of
Astragalus brauntonii
between Units 3 and 4 but is unable to disclose the locations because he entered into a “confidentiality clause” with the clients that commissioned surveys.

Our Response:
We are not entirely surprised that additional populations occur in the area between units 3 and 4, because this intervening area has similar features and PCEs to the two units. The Service has made a diligent effort to gather all sources of information concerning the distribution of this species, including surveys and other studies, biological assessments, other unpublished materials, and the personal knowledge of experts. Our proposed critical habitat was based on the best information available to us at the time.

9.
Comment:
A peer reviewer wanted to know why there were discussions of 4 PCEs for
Astragalus brauntonii
and
Pentachaeta lyonii
throughout the proposed rule, but only 3 PCEs were listed in the PCE section of the proposed rule.

Our Response:
Only three PCEs were included in the proposed rule. The reference to 4 PCEs in the proposed rule

was an error, which has been corrected in this final rule.

10.
Comment:
One peer reviewer suggested that a population viability analyses would assist us in designing critical habitat units that are large enough to assure persistence of sufficiently sized populations. Another peer reviewer thought that most of the units are too small and should be increased in size to reduce potential impacts of Argentine ant invasions on pollinators. Argentine ants are associated with manmade structures, and research has shown that they reduce native arthropod populations (e.g., bees and wasps) up to 656 ft (200 m) from their nests. The peer reviewer commented that Argentine ants could threaten the persistence of the plants because they would be expected to displace the pollinator community and suggested that we should include an additional “ant buffer” of 656 ft (200 m) around each unit, which would make the minimum unit size about 180 ac (73 ha).

Our Response:
We used the best scientific information available for this designation, and the Service does not typically conduct population viability analyses to assist in determining critical habitat. We acknowledge the potential indirect negative impacts of Argentine ants on the pollinators of these plant species and agree that a 656-ft (200-m) distance from the nearest edge of manmade structure may reduce any potential impacts. The impacts of Argentine ants on a rare native plant were discussed in a study by Conservation Biology Institute (2000). However, critical habitat, within the geographical range occupied by the species at the time it was listed, is defined by those physical and biological features essential to the conservation of the species (see Primary Constituent Elements section) which may require special management or protection. Physical and biological features essential to the conservation means PCEs arranged in the quantity and spatial characteristics necessary for conservation of the species. Critical habitat is not intended to create a preserve or other conservation area, or to include buffers in order to reduce impacts from manmade structures. The potential direct and indirect impacts to critical habitat and listed plants as a result of development of manmade structures would presumably be addressed through section 7 or other regulatory means. Therefore, while we recognize the reviewer's position, we believe that any identifiable impacts will be addressed through other regulatory means.

Comments From the State

Section 4(i) of the Act states, “the Secretary shall submit to the State agency a written justification for failure to adopt regulations consistent with the agency's comments or petition.” California Department of Fish and Game (CDFG) provided the following comments concerning the proposed critical habitat designation for
Astragalus brauntonii
and
Pentachaeta lyonii.

11.
Comment:
CDFG provided several corrections to our habitat description for
Pentachaeta lyonii.
They stated that
P. lyonii
is not always confined to flat slopes but is known to occur on slopes 20-30 percent or greater, and said it can occur on thin volcanic surface soils underlaid by near-surface volcanic rock, and in localized flat areas on steep slopes, dirt hiking trails, and old roadbeds.

Our Response:
We based our habitat description on the best available information to us at the time, but acknowledge that
Pentachaeta lyonii
may occur in a broader range of habitat preferences than was described in the proposed critical habitat.

12.
Comment:
CDFG stated that PCE 2 for
Astragalus brauntonii
, “Low proportion (<10%) of shrub cover directly around the plant,” was not entirely correct because the species may persist in the form of dormant seeds within mature stands of chaparral between episodes of fire. Therefore, occupied habitat would only contain PCE 2 at some points in successional time.

Our Response:
We recognize that
Astragalus brauntonii
occurrences may not contain PCE 2 all of the time, but this PCE is essential for the plant to be able to complete a necessary life history component—seed germination and plant growth. It is not necessary for all three PCEs to be present at a site at all times for it to be considered critical habitat.

13.
Comment:
CDFG said that we were incorrect in stating that
Pentachaeta lyonii
does not maintain a dormant seed bank, and that the species responds to favorable growing conditions with dramatic increases in population numbers and occupied acreage, suggesting that the species maintains some type of seed bank between years.

Our Response:
Keeley (1995) found that seeds buried more that
1/4
inch under the soil for more than 6 months did not germinate, leading to his conclusion that the species does not maintain a dormant seed bank. However, in a later study, he acknowledged that seeds likely remain dormant during drought years (Fotheringham and Keeley 1998), and hypothesized that seeds may need to be buried less than
1/4
inch to germinate following long-term dormancy periods. This hypothesis contradicted his previous conclusion that the species does not maintain a seed bank. We have corrected the final rule to reflect this information.

14.
Comment:
CDFG employees have observed
Pentachaeta lyonii
in habitat that does not appear to contain a biotic crust, so biotic crust should not be considered essential for all populations. In this critical habitat designation, PCE 2 is listed as “Exposed soils that exhibit a microbiotic crust which may inhibit invasion by other plant competitors.”

Our Response:
Although there has not been a specific study on biotic crusts and
Pentachaeta lyonii
, the habitat of this species was characterized in the listing rule by “a low percentage of total plant cover and exposed soils with a microbiotic crust, partially assisting with reducing competition with other species.” Crusts can be seen at many occupied sites of
P. lyonii
, and it is believed that these crusts reduce the ability of other plants to invade areas where
P. lyonii
occurs. We believe that this is an important PCE because it highlights a special management consideration for this species, which is that disturbance of the soil's surface crust should be avoided to prevent invasion by other plant species. We recognize that not every occurrence may contain microbiotic crusts, and it is not necessary for all three PCEs to be present at a site for it to be considered critical habitat.

15.
Comment:
CDFG noted that the minimum distance from one edge of a proposed unit to the other edge is insufficient to reduce potential adverse edge effects. They stated that Argentine ants, which are associated with manmade structures, are known to reduce native arthropod populations, including known insect pollinators of these species, such as bees and wasps. According to research, a distance of 328-656 ft (100-200 m) from the urban edge to core habitat is needed to ensure that core habitats remain free of Argentine ants.

Our Response:
As discussed in our response to comment 10, we acknowledge that there is the potential for indirect negative impacts of Argentine ants associated with manmade structures on the pollinators of these plant species, and agree that an additional 328-656 ft (100-200 m) distance beyond the proposed units and from the nearest urban edge may reduce

these impacts. However, in defining critical habitat, we believe that we have identified those areas that contain the PCEs essential to the conservation of the species which may require special management considerations or protections. The potential direct and indirect impacts to critical habitat and listed plants as a result of development of manmade structures would presumably be addressed through section 7 or other regulatory means.

16.
Comment:
CDFG commented that the true distribution of
Astragalus brauntonii
is not known because of the species' dormant seeds that may persist undetected in the soil for many years, and recommended using soil and geologic maps to capture additional potentially suitable habitat in the vicinity of known locations.

Our Response:
We included additional suitable habitat up to 935 ft (285 m) from known occurrences in order to capture areas that are likely to contain an undetected seed bank and to allow for genetic exchange between patches. We did not include habitat beyond the 935 ft (285 m) distance, because those areas are not known to be occupied by the species nor do we have evidence to support that this habitat is essential to the conservation of the species. We recognize that designation of critical habitat may not include all of the habitat areas that may ultimately be necessary for the recovery of the species, and therefore, critical habitat designations do not signal that habitat outside the designation is unimportant or not required for recovery.

17.
Comment:
CDFG commented that many of the units for both species lack connectivity to other units; suggested connecting units where there is potentially suitable geology or soils; and gave specific examples of units that could be connected.

Our Response:
We connected occurrences that were within 1,968 ft (600 m) of each other into single units to allow for genetic exchange between populations. We did not connect occurrences beyond that distance because they were not likely to be genetically connected. In some cases, units closer than 1,968 ft (600 m) from each other were not connected because the intervening habitat was developed and lacked the PCEs.

Public Comments on the Process of Designating Critical Habitat

18.
Comment:
One commenter stated that the “historic Stunt Ranch site” should be included for recovery purposes for potential reintroduction. This commenter is referring to occurrence number 3 in the CNDDB database record for
Pentachaeta lyonii.

Our Response:
As explained in our response to peer review comment 5, we did not include this occurrence because it currently does not appear to be suitable habitat for
Pentachaeta lyonii.
Despite the fact that this occurrence was not included in critical habitat, we recognize that there may be reintroduction potential for this site, and would consider reintroduction to be a valid recovery effort for the species.

19.
Comment:
One commenter disagreed with the Service's statement that “critical habitat provides relatively little additional protection to listed species” and asserted that critical habitat designations include information about the primary constituent elements the species needs for persistence and recovery. This information can be used by Federal and non-Federal agencies to develop a basic landscape scale long-term conservation strategy for the species.

Our Response:
As discussed in our response to peer review comment 2, the section referenced by the commenter is intended to be a general statement regarding our position on the designation of critical habitat. Although it is our position that the conservation and recovery of listed species are better served through other conservation mechanisms, we agree with the commenter's assertion that the information contained in this designation can be used to develop long-term conservation strategies for the species.

20.
Comment:
Several commenters thought that many of the units for both species were too small for a variety of reasons. They commented that we failed to account for areas needed for pollinator reproduction, which are different from pollinator foraging areas and may require larger patch sizes to support the pollinator population. One commenter asserted that additional area is needed to provide for pollinator persistence and pollinator linkages between populations of
Pentachaeta lyonii
, and that the minimum size needed to ensure persistence depends on local habitat conditions and the degree of isolation between patch sizes. The commenter noted that
P. lyonii
requires a low proportion of vegetative cover to persist, suggesting that patches should be larger to contain enough flowering plants to support pollinators. Similarly, a commenter thought critical habitat should be enlarged and merged to include appropriate soils and potential habitat and provide opportunities for pollinator dispersal. In the opinion of the commenter, this would provide corridors of connectivity, reducing habitat fragmentation and genetic isolation. Larger areas would also better support populations that shift in time and space, allow for ecosystem processes (including fire or fire-like disturbances) to function at appropriate scales, and minimize edge effects.

Our Response:
We generally agree with the conservation biology principles and rationale presented by the commenters. However, the Act states that critical habitat is “the specific areas within the geographical area occupied by the species * * * on which are found those physical or biological features essential to the conservation of the species” (i.e., PCEs (see Primary Constituent Elements section)). Furthermore, based on the Act, we only designate critical habitat in areas outside the geographical area occupied by the species at the time of listing when the best available information indicates that it is essential to the conservation of the species.

We used the best scientific information available to determine the necessary habitat to ensure persistence of individual populations. In order to reduce fragmentation and preserve genetic connectivity, we connected populations within 1,968 ft (600 m) of each other because they are likely to be visited by the same pollinators. We also designated suitable habitat to allow for important life-history functions such as seed dispersal and presence of pollinators, and included areas that likely contain a seed bank and/or unmapped patches within populations. We believe that our critical habitat design captures the areas essential to the conservation to the species based on the best scientific information currently available. We believe that by capturing entire populations within single critical habitat units and by connecting populations within 1,968 ft (600 m) of each other into single units, the species will persist and pollination will continue.

21.
Comment:
One commenter thought that surveys should be conducted for
Astragalus brauntonii
and
Pentachaeta lyonii
because of a wildfire that burned areas within the known distribution of the species, and any additional locations discovered should be included in critical habitat.

Our Response:
As discussed in our response to comment 6, we were unable to postpone our proposed designation of critical habitat further to incorporate the results of these surveys, although we funded post-fire surveys for
Astragalus brauntonii
in those areas that were burned and found additional locations

of the species. We determined that the fire did not burn within the known distribution of
Pentachaeta lyonii
, so there was no need for post-fire surveys.

22.
Comment:
One commenter thought that PCE 1 for
Astragalus brauntonii,
“carbonate limestone soils derived from marine sediment,” was not the best description of the soil type associated with the plant. A recent study in which soil samples were taken at locations of
A. brauntonii
revealed that the plant occurs with calcium carbonate soils (a broader range of soils), and not necessarily with limestone-derived soils (Landis 2005). The PCE as originally proposed could lead researchers to only look for
A. brauntonii
on soils that are obviously derived from limestone.

Our Response:
As stated in our response to comment 7, we have changed this PCE by removing the reference to limestone soils and adding calcium carbonate to the soils description. This change is also reflected in “Areas that Provide the Basic Requirements for Growth (Such as Water, Light, and Minerals)”.

23.
Comment:
Two commenters thought that an occurrence of
Astragalus brauntonii
located within the City of Oak Park should have been included within critical habitat because it contains the largest known seed bank in the Simi Hills. The commenters noted that inclusion of this occurrence, if a 3,281-ft (1,000-m) zone to protect pollinator habitat was incorporated, would link units 2c and 2d. In addition, one of the commenters stated that a “Rare Plant Conservation Plan” is in effect in the Oak Park area that covers three tiny preserves within open space and a “demonstration garden” that contains
A. brauntonii,
on land owned and managed by the Rancho Simi Recreation and Parks District. The commenter states that the plan does not adequately ensure the conservation and persistence of
A. brauntonii,
and should not be used as a basis to exclude this occurrence from critical habitat.

Our Response:
The commenters are referring to occurrence 20 in the CNDDB record for
Astragalus brauntonii.
We did not include this occurrence because it does not contain the PCEs. A large portion of this occurrence was removed by Rancho Simi Recreation and Parks District to create a city park, other portions were removed by urban development, and very small remaining portions are surrounded by or directly adjacent to urban development. It is difficult to determine the size of a seed bank, and there is no clear evidence that this occurrence contains the largest known seed bank in the Simi Hills, although small numbers of plants and a seed bank may remain within open space areas along the periphery of developed areas. Remaining portions of this occurrence are almost completely surrounded by urban development; therefore, we would be unable to link units 2c and 2d because we do not intentionally include developed areas such as buildings, paved areas, and other areas that lack the PCEs. Because this occurrence does not contain the PCEs, we did not evaluate the existing conservation plan as a basis for excluding this occurrence from critical habitat.

24.
Comment:
Several commenters identified portions of
Pentachaeta lyonii
populations that were not included in the designation (e.g., in subunit 2a, and Unit 4), and also thought that intervening habitat between subunits should have been included (e.g., between subunits 2b and 2c, and between the two parts of subunit 3c).

Our Response:
We do not intentionally include developed areas such as buildings, paved areas, and other areas that lack the PCEs in our critical habitat designations. Based on aerial photos of those areas (PhotoMapper 3.50, AirPhoto USA, NW Los Angeles Map 1999), we determined that those portions of populations and intervening habitat were previously removed by urban development.

25.
Comment:
A commenter thought we should have included
Pentachaeta lyonii
occurrences 9 and 19 from the CNDDB records in critical habitat.

Our Response:
We only included extant occurrences that contain the PCEs within critical habitat. We did not include occurrence 9 within the nearby Unit 7 (Malibu Lake unit) because, based on the CNDDB records, this occurrence has been extirpated since 1992. We did not include occurrence 19 because three of the four patches of
Pentachaeta lyonii
within this occurrence were removed by construction of a golf course. The fourth and only remaining patch is within approximately a 500 square-foot (46-square-meter) area, and is surrounded by the golf course. We believe that this remaining occurrence contains a population size of fewer than 10 individuals and may have even been extirpated. This location lacks the PCEs and has little recovery or conservation value; therefore, it was not included in the critical habitat designation.

26.
Comment:
There were several suggestions of simple management strategies for protecting both species that would not result in economic hardship on any jurisdiction or management agency, as well as suggestions for additional new criteria for delisting. For
Astragalus brauntonii,
suggested management techniques include: Lifting the blade of bulldozers at least 18 inches in the air when clearing roads or creating firebreaks; using weed-whackers to clear weeds around the plant; and leaving cut stalks and seedpods on the side of the road rather than removing
A. brauntonii
plant material. For
Pentachaeta lyonii,
suggested management techniques include routing roads around critical habitat areas and controlling non-native weeds invading critical habitat areas without the use of herbicides and without disturbing the soil. For both species, suggested management techniques include not transplanting plants as a conservation tool because both species are dependent on specific soil characteristics and performing road maintenance, fuel modification, and other management activities after fruiting.

Our Response:
We have incorporated some of the management strategies into the section titled “Special Management Considerations or Protections” in this rule. We may also provide these suggestions, in the form of best management practices, to local agencies when we provide technical assistance regarding ways to reduce impacts to listed species, and to Federal agencies through the section 7 consultation process. The suggested new criteria for delisting are valid recovery actions that we may attempt to accomplish in future recovery actions for the species. These criteria may also be incorporated into a revised recovery plan at some point in the future.

27.
Comment:
One commenter thought that the proposed critical habitat only maintains both species at their current level with no opportunity for recovery because we do not propose unoccupied suitable habitat. Other commenters thought that we should have included unoccupied suitable habitat on land owned by the National Park Service (NPS) or by local open space agencies because they represent opportunities for population expansion for the species. They noted that an experimental population of
Pentachaeta lyonii
was recently introduced at Paramount Ranch on NPS land, illustrating the potential for reintroductions into other areas.

Our Response:
We disagree with the commenter that our proposal and designation do not provide opportunities for recovery of the species. Our critical habitat designation noted the fact that both plants occur in patchy distributions both physically and temporally. In order to incorporate

entire populations, we conducted a nearest neighbor analysis and determined that the average distance between patches of plants was 275 m (902 ft) for
Pentachaeta lyonii
and 285 m (935 ft) for
Astragalus brauntonii.
Therefore, in areas where the habitat was contiguous and PCEs were present, we included suitable habitat up to 275 m (902 ft) and 285 m (935 ft) from known patches of
P. lyonii
and
A. brauntonii,
respectively, to ensure that we captured the entire population (including the seed bank) within one critical habitat unit and minimized fragmentation. Furthermore, where we had populations within 600 m (1,968 ft) of one another and the habitat was contiguous and contained the PCEs, we connected those populations together in one unit to facilitate genetic exchange between populations through pollinator activity. We expect that these areas contain a seed bank, and/or additional suitable habitat for population expansion through seed dispersal. Both of these strategies capture recovery opportunities for the species and, through these strategies, we believe we have captured the entire area necessary to ensure persistence of the species. For further information, please refer to the “Criteria Used to Identify Critical Habitat” section. Although we did not designate specific areas of unoccupied habitat for potential reintroductions, we believe that this can be an important recovery tool for
P. lyonii,
particularly on Federal Lands, and we support these types of actions. We recognize that designation of critical habitat may not include all of the habitat areas that are necessary for the recovery of the species, and therefore, critical habitat designations do not signal that habitat outside the designation is unimportant or not required for recovery.

28.
Comment:
A researcher commented that we were incorrect in stating that
Pentachaeta lyonii
does not maintain a dormant seed bank. Surveys conducted in multiple years at the same site show large fluctuations in population size, and this would likely be impossible unless the species maintains a seed bank for at least 5 to 10 years.

Our Response:
As discussed in our response to comment 13 from the State, we have corrected the final rule to reflect this information.

29.
Comment:
A researcher commented that the role of biotic crusts is unsupported by data and that this should not be used for PCE 2 for
Pentachaeta lyonii
because it suggests that crust is a required element for
P. lyonii
habitat. In the proposed designation, PCE 2 was listed as “Exposed soils that exhibit a microbiotic crust which may inhibit invasion by other plant competitors.”

Our Response:
As discussed in our response to comment 14, we recognize that not every occurrence may contain microbiotic crusts, and it is not necessary for all three PCEs to be present at a site for it to be considered critical habitat.

30.
Comment:
A researcher commented that PCE 3 for
Pentachaeta lyonii
should focus on the presence of bare ground rather than on proportion of vegetative cover. In the proposed designation, PCE 3 was listed as “low proportion of total vegetative cover (<25%).” The commenter asserted that this PCE can be misleading because, based on research,
P. lyonii
is found in areas with 20 to 60 percent cover of native vegetation at a larger scale (i.e., 538 to 2,153 square foot patch sizes (50 to 200 square meter)). Although the species can be found in areas with a larger proportion of total vegetative cover, there needs to be small openings of bare ground for the plant to grow in (i.e., > 10% bare ground on a small scale of less than approximately 3 ft (1 m) because it does not compete well with other species. In addition, the researcher found that plant litter accumulation associated with annual grass invasion reduces
P. lyonii
populations. The commenter indicated that this finding further highlights that bare ground is an essential component of this species' habitat.

Our Response:
We agree with the researcher's comment, and have changed
P. lyonii
PCE 3 to read: “a mosaic of bare ground (>10%) patches in an area with less than 60 percent cover.” We believe this more accurately reflects the physical and biological needs essential to the conservation of the species.

31.
Comment:
A researcher commented that we should have a PCE that addresses habitat quality based on presence of
Pentachaeta lyonii
-associated native plant species and the absence of non-native invasive plants.
P. lyonii
habitat that is in decline shows increased presence of non-native species, build-up of litter cover and loss of bare ground, and slow loss of associated species.

Our Response:
We agree that presence of non-native invasive plants indicates poor habitat quality for
Pentachaeta lyonii,
and that presence of some associated native species can be a good indicator of good habitat quality, and this concept was discussed in the proposed and final rule. However, we believe that PCEs 2 and 3 adequately capture habitat quality, because it is unlikely that either PCE would exist if the unit became overtaken with non-native invasive plants.

Comments Related to the Draft Economic Analysis

32.
Comment:
Two commenters stated that economic analysis overestimates the cost of critical habitat designation because it will affect real estate development on private lands only where there is a Federal nexus. Such a nexus will not exist for most projects in the area proposed as critical habitat.

Our Response:
We recognize that real estate development on private lands does not come under the purview of the section 7 consultation process unless there is a Federal nexus. However, it is difficult to predict which future actions may bare a Federal nexus. The methodology of the analysis quantifies future costs when it is possible to isolate and measure them and then calculates the economic surplus resulting from future activities that may take place within proposed critical habitat. This approach avoids speculation about regulatory impacts. It is, however, possible to calculate the value added from development activities within areas of critical habitat. By using this methodology, we believe we have appropriately captured potential costs to the real estate development sector.

33.
Comment:
One commenter stated that costs that occurred prior to designation should not be included in the cost of critical habitat designation.

Our Response:
Based on the 10th Circuit Court's ruling in
New Mexico Cattle Growers Association
v.
U.S. Fish and Wildlife Service, 248 F.3d 1277, 128 (10th Cir. 2001)
the Service conducts a full analysis of all the economic impacts of a critical habitat designation, regardless of whether those impacts are attributable co-extensively to other causes. Accordingly, here, the economic analysis specifies that it considers the future economic impacts associated with critical habitat designation and past costs that have resulted from efforts to conserve the species within areas of critical habitat. As explained in section III.1, past costs are defined as costs that occurred between when the species was listed under the Endangered Species Act and the present. These past costs are not attributable to critical habitat.

34.
Comment:
One commenter suggested that past development projects in areas of critical habitat should be analyzed to determine the limitations on development arising from critical habitat.

Our Response:
The economic analysis uses consultation history to determine how many future development projects

will have a Federal nexus and what the recommended restriction on development will be. For both species in question, the number of available consultations on private development projects is highly limited or nonexistent. The available evidence, however, suggests that total avoidance of the species has been required in the past; for example, the 1999 consultation with Lennar Homes referenced in the report.

35.
Comment:
One commenter stated that that local zoning and other restrictions limit the pace of development, thus reducing the costs of critical habitat.

Our Response:
We agree that local regulation plays a large role in determining the timing and intensity of development. The development projections from the Southern California Association of Governments (SCAG) that form the basis of the economic modeling incorporate these restrictions.

36.
Comment:
One commenter stated that there are many additional benefits of critical habitat designation beyond just the conservation of habitat for the listed species, and that these should be included in the economic analysis.

Our Response:
In the context of a critical habitat designation, the primary purpose of the rulemaking (i.e., the direct benefit) is to designate areas in need of special management that contain the features that are essential to the conservation of listed species.

The designation of critical habitat may result in two distinct categories of benefits to society: (1) Use; and (2) non-use benefits. Use benefits are simply the social benefits that accrue from the physical use of a resource. Visiting critical habitat to see endangered species in their natural habitat would be a primary example. Non-use benefits, in contrast, represent welfare gains from “just knowing' that a particular listed species” natural habitat is being specially managed for the survival and recovery of that species. Both use and non-use benefits may occur unaccompanied by any market transactions.

A primary reason for conducting this analysis is to provide information regarding the economic impacts associated with a proposed critical habitat designation. Section 4(b)(2) of the Act requires the Secretary to designate critical habitat based on the best scientific data available after taking into consideration the economic impact, and any other relevant impact, of specifying any particular area as critical habitat. Economic impacts can be both positive and negative and by definition, are observable through market transactions.

Where data are available, the analysis attempt to recognize and measure the net economic impact (i.e., the increased regulatory burden less any discernable offsetting market gains), of species conservation efforts imposed on regulated entities and the regional economy.

Under Executive Order 12866, OMB directs Federal agencies to provide an assessment of both the social costs and benefits of proposed regulatory actions. OMB's Circular A-4 distinguishes two types of economic benefits: direct benefits and ancillary benefits. Ancillary benefits are defined as favorable impacts of a rulemaking that are typically unrelated, or secondary, to the statutory purpose of the rulemaking. In the context of critical habitat, the primary purpose of the rulemaking (i.e., the direct benefit) is the potential to enhance conservation of the species. The published economics literature has documented that social welfare benefits can result from the conservation and recovery of endangered and threatened species. In its guidance for implementing Executive Order 12866, OMB acknowledges that it may not be feasible to monetize, or even quantify, the benefits of environmental regulations due to either an absence of defensible, relevant studies or a lack of resources on the implementing agency's part to conduct new research. Rather than rely on economic measures, the Service believes that the direct benefits of the proposed rule are best expressed in biological terms that can be weighed against the expected cost impacts of the rulemaking.

We have accordingly considered, in evaluating the benefits of excluding versus including specific areas, the biological benefits that may occur to a species from designation (see below, Exclusions Under section 4(b)(2) of the Act), but these biological benefits are not addressed in the economic analysis.

37.
Comment:
One commenter stated that Section 9 of the ESA is flawed, and allows extirpation of plants in areas outside federal jurisdiction. The comment asserts that critical habitat is important to the conservation of the species by prohibiting take, requiring mitigation and facilitating the development of recovery plans.

Our Response:
Critical habitat does not prohibit take of plants on private lands, or require mitigation for private activities. Critical Habitat only affects private activities when a project requires a Federal permit, approval or funding. The Act requires the Service to develop recovery plans independent of critical habitat designations.

38.
Comment:
One commenter thought that the cost estimated in the economic analysis was too high because it includes costs attributable to listing as opposed to costs of critical habitat designation. A second commenter asserted that it was unlawful to report the coextensive costs of conserving the species and that only the incremental costs resulting from critical habitat should be reported.

Our Response:
The primary purpose of the economic analysis is to estimate the potential economic impacts associated with the designation of critical habitat for these two species. We interpret the Act to require that the economic analysis include all of the economic impacts associated with the conservation of the species, which may include some of the effects associated with listing. We note that the Act generally requires critical habitat to be designated at the time of listing, and if we had conducted an economic analysis at that time, the impacts associated with listing would not be readily distinguishable from those associated with critical habitat designation.

39.
Comment:
One commenter indicated that the majority of lands designated as critical habitat are already conserved as open space and thus not likely to be developed.

Our Response:
We agree that a significant amount of land within the areas proposed as critical habitat has been conserved as open space via long-term agreements. We have detailed these agreements for each unit of proposed critical habitat. Projected development in the economic analysis is limited to areas that fall outside these conservation commitments.

40.
Comment:
One commenter asserted that SCAG projections are inadequate since they fail to consider local zoning requirements and capture only the potential for development in various regions.

Our Response:
The SCAG development projections are the best information available on the extent, timing and placement of real estate development in the Los Angeles metropolitan region. These forecasts are based on aggregate projections of economic activity and employment, as well as location-specific factors such as zoning and other local factors.

41.
Comment:
One commenter stated that the costs presented in Table 1 of the Draft Economic Analyses are overstated because portions of proposed critical habitat are public lands.

Our Response:
The totals presented in Table 1 are associated with development occurring on private land only.

42.
Comment:
One public comment stated that there is a discrepancy in the “Surplus per Developed Acre” between Table 1 and the text.

Our Response:
Table 1 is correct, however, the corresponding figure presented in the text ($2,714,359) is not. This has been corrected in the final economic analysis.

43.
Comment:
One commenter stated that the small business analyses are incomplete.

Our Response:
These sections have been expanded in the final economic analyses.

44.
Comment:
One commenter stated that it is unclear how the IMPLAN (economic modeling software) analyses calculated such a high number when the designation of critical habitat does not prevent development.

Our Response:
The regional economic analysis considers the secondary effects of housing construction within the areas proposed as critical habitat. We note, however, that estimated secondary effects are small when considered as a fraction of the total contribution of the housing industry to the Southern California economy.

45.
Comment:
One commenter stated that it is unclear how the IMPLAN Analyses evaluates the secondary effects of critical habitat designation on other industries.

Our Response:
Section V Regional Economic Impacts contains an explanation of how IMPLAN, which is an input-output model, computes indirect and induced effects. See also Table 3, which breaks down the secondary effects of designation to each industry.

46.
Comment:
One commenter asserted that the costs presented in Table 1 are significantly higher than they should be because they are associated with the designation on public and private lands.

Our Response:
The costs presented in the reports are estimated based on the private land projected for development, not the public and private land proposed for critical habitat designation.

47.
Comment:
One commenter stated that there are other discrepancies between the text and Table 1, including the “Projected Households”.

Our Response:
Table 1 presents the projected households, which is consistent with the projected households in the text. Table 3 presents the households allowed by zoning, which is also consistent with the zoning allowances in the text.

48.
Comment:
One commenter requested to be excluded under 4(b)(2) of the Act based on economic impacts of critical habitat on their property. The landowner owns the property within the proposed Unit 6 for
Pentachaeta lyonii
and has proposed to develop 81 residential units on the property.

Our Response:
Section 4(b)(2) of the Act requires the Secretary to designate critical habitat based on the best scientific data available after taking into consideration the economic impact, impact on national security, and any other relevant impact, of specifying any particular area as critical habitat. We received additional information from the landowner in a Memorandum, dated March 3, 2006, which estimated that the lost revenue as a result of critical habitat on their proposed development, if they avoided impacts to the species, would be approximately $78 million. As a result, Unit 6 in its entirety has been excluded from the final rule. See Exclusions Under Section 4(b)(2) of the Act section below for more details.

Summary of Changes From Proposed Rule

(1) We modified our criteria for delineating the outer boundaries of each unit resulting in minor reductions in unit sizes. In the proposed rule, the outer boundaries of each unit or subunit extended to 984 ft (300 m) on all sides of each mapped patch, which would presumably incorporate the minimum size habitat necessary to support associated insect pollinators. However,
A. brauntonii
and
P. lyonii
are known to be pollinated by several insect pollinators, and nonspecific pollinators are not a Primary Constituent Element (PCE) for either species. Upon further consideration, we felt we needed to better define and map the critical habitat boundaries. In looking at the mapping information from all mapped records (i.e., from the CNDDB database and from records collected from other sources), we noticed that the distribution of plants was often patchy, both at any one moment in time and over time. In other words, the plants were often expressed at different locations within a single area or population. This evidence supports the presence of a seed bank. In order to define when patches were within a single population and include areas with a seed bank, we conducted a nearest neighbor analysis for both species using all available mapped occurrences. To do this, we used GIS to determine the distance from the centroid of each mapped occurrence or “patch” to the centroid of the nearest mapped occurrence. We determined that the average distance between patches within populations was 935 ft (285 m) for
Astragalus brauntonii
and 902 ft (275 m) for
Pentachaeta lyonii
. Therefore, in the final designation, we designated additional suitable habitat up to 935 ft (285 m) from each mapped patch of
A. brauntonii
to incorporate the patchy expression of populations in space and over time, include unmapped patches within populations, incorporate the existing seed bank, and include areas for seed dispersal and genetic exchange through pollinator activity. For
P. lyonii
, we designated additional suitable habitat up to 902 ft (275 m) from each mapped patch to incorporate the patchy expression of the plant in space and time, include unmapped patches within populations, incorporate the existing seed bank, and include areas for seed dispersal and genetic exchange through pollinator activity. See the Criteria Used to Identify Critical Habitat section for details on the revised criteria. Table 1 for
A. brauntonii
and Table 3 for
P. lyonii
shows the proposed and final acreages of each unit that were changed based on the new criteria.

(2) We made corrections on ownership of lands within several units. The ownership of subunit 1c for
Pentachaeta lyonii
was misidentified as being entirely owned by Calleguas Municipal Water District. We determined that, in the proposed rule, the ownership of the land within this subunit is 49 ac (19 ha) of private land and only 2 ac (1 ha) of land owned by Calleguas Municipal Water District. After applying the revised criteria, in this final rule, the entire unit (33 ac (13 ha)) is on private land. The ownership of subunit 2b for
P. lyonii
was misidentified as 31 ac (13 ha) owned by Conejo Open Space Conservation Agency (COSCA), and 16 ac (6 ha) of private land; after identifying the correct ownership and applying the revised criteria, 22 ac (9 ha) is owned by COSCA and 18 ac (7 ha) is on private land. The ownership of subunit 1d for
Astragalus brauntonii
was misidentified as being owned by Rocketdyne. However, Rocketdyne sold this property to Boeing. In addition, it was determined that a small portion of this subunit is owned by a local agency. After identifying the correct ownership and applying the revised criteria, 68 ac (27 ha) is owned by Boeing and 2 ac (1 ha) is owned by a local agency (Santa Monica Mountains Conservancy). The ownership of subunit 2a for
A. brauntonii
was misidentified as 235 ac (95 ha) owned by COSCA, and 217 ac (88 ha) of private land; after identifying the correct ownership and applying the revised criteria, 118 ac (48 ha) is owned by the State, 221 ac (89 ha) is owned by COSCA, and 71 ac (29 ha) is on private land.

(3) We corrected the reference to soils in PCE 1 for
Astragalus brauntonii
from “carbonate limestone soils derived from marine sediment” to “calcium carbonate soils derived from marine sediment,” because we believe that this is a more accurate description of the soil type. A recent study in which soil samples were taken at most locations of
A. brauntonii
revealed that the plant occurs in areas with calcium carbonate soils (a broader range of soils), and not necessarily where soils are derived from limestone (Landis 2005). This correction is also reflected in the discussion of Areas that Provide the Basic Requirements for Growth (Such as Water, Light, and Minerals).

(4) We changed PCE 3 for
Pentachaeta lyonii
from “low proportion of total vegetative cover (<25%)” to “a mosaic of bare ground (>10%) patches in an area with less than 60 percent cover,” because we believe that this is a more accurate and complete description of the habitat. This is based on a recent habitat study of the species conducted by Santa Monica Mountains National Recreation Area. This correction is also reflected in the discussion of Areas that Provide the Basic Requirements for Growth (Such as Water, Light, and Minerals).

(5) We changed PCE 3
Astragalus brauntonii
from “periodic disturbances that stimulate seed germination (e.g., fire, flooding, erosion) and reduce vegetative cover” to “chaparral and coastal sage scrub communities characterized by periodic disturbances that stimulate seed germination (e.g., fire, flooding, erosion) and reduce vegetative cover,” because we believe that a PCE should not be a physical process, but a habitat condition that occurs in part as a result of the physical process. The revised PCE allows for easier identification of its presence because it would be expected to be present at any point in time, whereas the original PCE is more difficult to identify because it occurs only periodically.

(6) We excluded Unit 6 for
Pentachaeta lyonii
(223 ac (94 ha)) under section 4(b)(2) of the Act from the final critical habitat designation based on economic impacts to the landowner. See Exclusions Under Section 4(b)(2) of the Act section for a detailed discussion.

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) essential to the conservation of the species and (II) that 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, as defined under section 3 of the Act, means to use and the use of all methods and procedures that are necessary to bring any endangered species or threatened species to the point at which the measures provided pursuant to the Act are no longer necessary. 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 be otherwise relieved, may include regulated taking.

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. Section 7 is a purely protective measure and does not require implementation of restoration, recovery, or enhancement measures.

To be included in a critical habitat designation, the habitat within the area occupied by the species 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 data available, habitat areas that provide essential life cycle needs of the species (i.e., areas on which are found the primary constituent elements, 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. Areas outside of the geographic area occupied by the species at the time of listing may only be included in critical habitat if they are essential for the conservation of the species. Accordingly, when the best available scientific data do not demonstrate that the conservation needs of the species require additional areas, 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 was not known to be occupied at the time of listing will likely, but not always, be essential to the conservation of the species and, therefore, typically 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 data available. They require Service 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 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.

Primary Constituent Elements

In accordance with section 3(5)(A)(i) of the Act and regulations at 50 CFR 424.12, in determining which areas to designate as critical habitat, we consider those physical and biological features (PCEs) that are essential to the conservation of the species, and within areas occupied by the species at the time of listing, 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 distributions of a species.

The specific PCEs required for
Astragalus brauntonii
and
Pentachaeta lyonii
are derived from the physical and biological features that are essential to the conservation of the species as described below.

Astragalus brauntonii

Space for Individual and Population Growth, Including Sites for Germination, Pollination, Reproduction, and Seed Bank

Seeds of
Astragalus brauntonii
are enclosed in dense hairy pods and require heat or physical scarification (breaking, scratching, or mechanically altering the seed coat) to germinate. Disturbances such as fire, erosion, and human activities such as mechanical scraping of soil (e.g., during road or trail maintenance) are known to stimulate germination (Fotheringham and Keeley 1998). Each seed pod produces between three and six seeds, and each plant may support upwards of several hundred flowers (Barneby 1964). Therefore, plants may produce a large number of seeds before dying back, depositing a seed “bank” in the soil that has the ability to remain dormant for many years until the next disturbance. Plant seeds are frequently dispersed by a variety of vectors, some which result in short-distance dispersal, and others which result in long-distance dispersal (Cain
et al.
2000; Nathan and Muller-Landau 2000). Because the seeds of
A. brauntonii
have no specialized adaptations to facilitate seed dispersal by wind, it is likely that most seed fall within a short distance of the parent plant (Cain
et al.
2000). Long-distance dispersal, however, is likely achieved by water (during rainstorms), and by transport of seeds by wildlife. Seeds from species within the Fabaceae family are known to be transported by small seed-eating mammals, including ground squirrels (
Citellus
sp.) pocket mice (
Perognathus
sp.), kangaroo rats (
Dipodomys
sp.), and birds, including quail (
Lophortyx
sp.) (Martin
et al.
1961). Small mammals facilitate seed dispersal through consumption and elimination of undigested seed and through seed caching (Cain
et al.
2000; Sieg 1987).

The presence of a persistent seed bank makes it difficult to determine the complete distribution of the species at any one point in time. Where a dormant seed bank is present,
Astragalus brauntonii
establishes quickly after a disturbance that removes other plant competitors and stimulates germination of dormant seeds (Fotheringham and Keeley 1998). Individual plants have a lifespan of two to three years, although some individuals may live five years or more if conditions are favorable, and then plants may not be visible again until the next disturbance (Fotheringham and Keeley 1998).

Like many other
Astragalus
species,
Astragalus brauntonii
is self-fertile, and also produces seed through cross-pollination (Fotheringham and Keeley 1998). Insect pollinators of
A. brauntonii
are polylectic, meaning that they utilize several plant species within an area (Karron 1987), and a variety of plants may be necessary to sustain populations of pollinators. Insect visitors include megachilid bees and bumblebees (Fotheringham and Keeley 1998). Gathmann and Tscharntke (2002) determined that maximum foraging distance of several species of solitary bees was positively correlated with body length. The body length of megachilid bees ranges 0.24-0.47 inches (in) (6-12 millimeters (mm)). Based on the linear regression model calculated by Gathmann and Tscharntke (2002), the maximum foraging distance of megachilid bees is 492-1,968 ft (150-600 m). The body length of bumblebees (
Bombus
sp.) ranges 0.51-0.98 in (13-25 mm), giving them a maximum foraging distance of 1,968-3,937 ft (600-1,200 m) (Gathmann and Tscharntke 2002). Therefore, known pollinators of
P. lyonii
have the ability to pollinate individual plants up to 1,968 ft (600 m) from the pollen source, suggesting that genetic connectivity can occur between populations that are up to 1,968 ft (600 m) apart from each other.

Areas That Provide the Basic Requirements for Growth (Such as Water, Light, and Minerals)

Astragalus brauntonii
may be limited to shallow calcium carbonate 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
Astragalus 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). It may persist for several years 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). 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). The above-ground expression of
A. brauntonii
populations are patchy over time and space as a result of the dormant seed

bank and dynamic habitat conditions and physical processes where it occurs.

Primary Constituents for Astragalus brauntonii

Pursuant to our regulations, we are required to identify the known physical and biological features (PCEs) essential to the conservation of
Astragalus brauntonii
. All areas designated as critical habitat for
A. brauntonii
are occupied, within the species' historic geographic range, and contain sufficient PCEs to support at least one life history function.

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 for
Astragalus brauntonii
are:

(1) Calcium carbonate soils derived from marine sediment;

(2) Low proportion (<10%) of shrub cover directly around the plant; and

(3) Chaparral and coastal sage scrub communities characterized by periodic disturbances that stimulate seed germination (e.g., fire, flooding, erosion) and reduce vegetative cover.

This designation is designed for the conservation of those areas containing PCEs necessary to support the life history functions that were the basis for the proposal. Because not all life history functions require all the PCEs, not all critical habitat will contain all of the PCEs.

Units are designated based on sufficient PCEs being present to support one or more of the species's life history functions. Some units contain all PCEs and support multiple life processes, while some units contain only a portion of the PCEs necessary to support the species' particular use of that habitat. Where a subset of the PCEs is present at the time of designation, this rule protects those PCEs and thus the conservation function of the habitat.

Pentachaeta lyonii

Space for Individual and Population Growth, Including Sites for Germination, Pollination, Reproduction, and Seed Bank

Pentachaeta lyonii
is an annual plant that may exhibit large fluctuations in population size between years (Keeley and Baer-Keeley 1992). Population boundaries exhibit annual fluctuations, although the plants generally remain within core areas that contain suitable microsite characteristics (Keeley and Baer-Keeley 1992). Each flower produces 30 or more seed heads, and each seed head produces 20 to 40 seeds; therefore, in a favorable year, an individual plant may produce on the order of 1,000 seeds. The seeds likely persist in the soil for several years during extended dry spells (Fotheringham and Keeley 1998). Plant seeds are frequently dispersed by a variety of vectors, some which result in short-distance dispersal, and others which result in long-distance dispersal (Cain
et al.
2000; Nathan and Muller-Landau 2000). 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 by this method (Keeley and Baer-Keeley 1992; Fotheringham and Keeley 1998). Long-distance dispersal, however, is likely achieved by transport of seeds by wildlife. Seeds from species within the Asteraceae family are known to be transported by small seed-eating mammals, including ground squirrels (Citellus sp.) pocket mice (Perognathus sp.), kangaroo rats (Dipodomys sp.), and birds, including quail (Lophortyx sp.) (Martin
et al.
1961). Small mammals facilitate seed dispersal through consumption and elimination of undigested seed and through seed caching (Cain
et al.
2000; Sieg 1987).

Pentachaeta 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 pollinators are polylectic, meaning that they utilize several plant species within an area (Braken and Verhoeven 1998), and a variety of plants are necessary to sustain pollinator populations. Based on the linear regression model calculated by Gathmann and Tscharntke (2002), the maximum foraging distance of digger bees (body length 0.51-0.75 in; 13-19 mm) is approximately 1,968 ft (600 m), and the maximum foraging distance of megachilid bees (body length 0.24-0.47 in; 6-12 mm) is 492-1,968 ft (150-600 m). The maximum foraging distance of andrenid bees is 853-1,640 ft (260-500 m) (Gathmann and Tscharntke 2002). Therefore, known pollinators of
P. lyonii
have the ability to pollinate individual plants up to 1,968 ft (600 m) from the pollen source, suggesting that genetic connectivity occurs between populations that are up to 1,968 ft (600 m) apart from each other.

Areas That Provide the Basic Requirements for Growth (Such as Water, Light, and Minerals)

Pentachaeta 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 similar to those described above for
Astragalus brauntonii
. 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.

Primary Constituents for Pentachaeta lyonii

Pursuant to our regulations, we are required to identify the known physical and biological features (PCEs) essential to the conservation of
Pentachaeta lyonii.
All areas designated as critical habitat for
P. lyonii
are occupied, within the species' historic geographic range, and contain sufficient PCEs to support at least one life history function.

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 for
Pentachaeta 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) A mosaic of bare ground (>10%) patches in an area with less than 60 percent cover.

This designation is designed for the conservation of the PCEs necessary to support the life history functions that were the basis for the proposal. Because not all life history functions require all the PCEs, not all critical habitat will contain all of the PCEs.

Units are designated based on sufficient PCEs being present to support one or more of the species's life history functions. Some units contain all PCEs and support multiple life processes,

while some units contain only a portion of the PCEs necessary to support the species' particular use of that habitat. Where a subset of the PCEs is present at the time of designation, this rule protects those PCEs and thus the conservation function of the habitat.

Criteria Used To Identify Critical Habitat

As required by section 4(b)(1)(A) of the Act, we use the best scientific and commercial data available in determining areas that contain the features that are essential to the conservation of
Astragalus brauntonii
and
Pentachaeta 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 CNDD (2003); data in reports submitted during section 7 consultations; recent biological surveys; regional 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
Astragalus 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
Pentachaeta lyonii
(Belnap 1990; Keeley and Baer-Keeley 1992; Keeley 1995; Braker and Verhoeven 1998; Fotheringham and Keeley 1998; Gathmann and Tscharntke 2002).

We designated critical habitat on lands that were occupied at the time of listing, are currently known to be occupied, and contain sufficient PCEs to support life history functions essential for the conservation of
Astragalus brauntonii
and
Pentachaeta lyonii
, and may be in need of special management considerations or protections. In a few instances, we designated occupied areas that were identified after listing, but which we determined to be essential to the conservation of
A. brauntonii
and
P. lyonii.

We reevaluated the proposed designations based on public comment, peer review, the economic analysis of the proposed rule, public comments on the economic analysis, and other available and new information to ensure that the designation accurately reflects habitat containing the physical and biological features essential to the conservation of
Astragalus brauntonii
and
Pentachaeta lyonii.

Astragalus brauntonii

We designated critical habitat for
Astragalus brauntonii
—supporting areas that were known to be occupied at the time of listing and contain the features essential to the conservation of the species. We also designated occurrences not known to be occupied at the time of listing but which are currently occupied, and were determined to be essential to the conservation of the species. We included occurrences not known to be occupied at the time of listing because this species is extremely limited in distribution and often occurs in very small disjunct populations, making it particularly vulnerable to extinction. According to Noss
et al.
(1997), a species distributed across multiple sites within its range is less susceptible to extinction than another similar species confined to far fewer sites. As a result, being restricted to small, isolated locations makes the species more vulnerable to threats such as loss of genetic variation, extremely small or declining population sizes, and increased vulnerability to stochastic (i.e., random or less predictable) events. Inclusion of all known occurrences that still contain the PCEs was deemed necessary in this instance to reduce fragmentation and helps to maintain genetic connectivity between populations and increase the chance of recolonization from neighboring patches if one patch becomes extirpated.

We designated critical habitat for
Astragalus brauntonii
in areas that contained known populations and additional surrounding suitable habitat that likely supports unmapped or unknown patches present but missed during surveys within populations, and likely incorporates the existing seed bank. We included patches of surrounding suitable habitat, using the method described below, around known plant locations because of the difficulty of knowing the full distribution given the long dormancy of this species' seed bank and the aboveground expression of the plant in different portions of the species' range over time. Inclusion of this surrounding suitable habitat allows for necessary life history functions such as seed dispersal, support of associated insect pollinators, and appropriate periodic ground disturbances in order to stimulate dormant seeds within the soil to germinate. We also connected units within close geographic proximity to each other to maintain genetic connectivity between populations, reduce fragmentation, and to include contiguous habitat for pollinators and seed dispersal. A detailed description of how we determined areas appropriate for inclusion follows.

We used a multi-step process to map critical habitat units. First, we mapped all CNDDB records of
Astragalus brauntonii
in a GIS format. These data consist of polygons (figures made up of several line segments) depicting the results of field surveys for
A. brauntonii.
Additional records from recent surveys that are not in the CNDDB records were also mapped in a GIS format. To determine areas where unmapped or unknown patches within populations are likely to occur, and to include areas that contain an unknown or unexpressed seed bank, we measured the distance from the centroid of each known occurrence or “patch” to the centroid of the nearest neighboring patch, and found that the average distance between nearest patches was 935 ft (285 m). Therefore, we included additional suitable habitat up to 935 ft (285 m) from known occurrences to incorporate entire populations that are patchy in time and space.

Then, we connected areas that were within 1,968 ft (600 m) of each other, because this is the distance between populations that could be traversed by important insect pollinators, and this approach allows for genetic exchange and connectivity between populations and reduces fragmentation. As discussed in the PCEs section, known pollinators of
Astragalus brauntonii
include megachilid bees and bumblebees. Based on body length, foraging ranges are approximately 492-1,968 ft (150-600 m) for megachilid bees and 1,968-3,937 ft (600-1,200 m) for bumblebees (Gathmann and Tscharntke 2002). We chose 1,968 ft (600 m) as the maximum distance to connect known populations because 1,968 ft (600 m) is the minimum foraging range for bumblebees, and megachilid bees also fall within this foraging range. Plant communities between these areas would also support insect pollinators and seed dispersers of
A. brauntonii,
and may also contain unknown or unmapped populations and/or a dormant seed bank.

Pentachaeta lyonii

We designated critical habitat for areas that support occurrences of
Pentachaeta lyonii
that were known to be occupied at the time of listing and contain the features essential to the conservation of the species. We also designated occurrences not known to be

occupied at the time of listing but which are currently occupied; however, these occurrences are within the geographic range of occurrences known to be occupied at the time of listing and contain the features essential to the conservation of the species. With the exception of Unit 6, we included all known occurrences that still contain the PCEs because this species is extremely limited in distribution, and patches exhibit large annual fluctuations in population numbers and area, making it particularly vulnerable to extinction. According to Noss
et al.
(1997), a species distributed across multiple sites within its range is less susceptible to extinction than another similar species confined to far fewer sites. As a result, being restricted to small, isolated locations makes the species more vulnerable to threats such as loss of genetic variation, extremely small or declining population sizes, and increased vulnerability to stochastic (i.e., random or less predictable) events. Inclusion of all known occurrences, with the exception of Unit 6, that still contain the PCEs reduces fragmentation, maintains genetic connectivity between populations, and increases the chance of recolonization from neighboring patches if one patch becomes extirpated.

We designated critical habitat for
Pentachaeta lyonii
in areas that contained known populations and additional surrounding suitable habitat that likely includes unmapped or unknown patches present but missed during surveys within populations, and incorporates the existing seed bank. We included surrounding habitat around known plant locations, using the method described below, because the boundaries of patches fluctuate between years, and this species' ability to maintain a seed bank during extended dry spells makes it difficult to know the full distribution of the species. Inclusion of surrounding suitable habitat allows for support of associated insect pollinators. We also connected units within close geographic proximity to each other to maintain genetic connectivity between populations, reduce fragmentation, and include contiguous habitat for pollinators and allow for population boundaries to expand.

We used a multi-step process to map critical habitat units. First, we mapped all CNDDB records of
Pentachaeta 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 records were also mapped in a GIS format. To determine areas where unmapped or unknown patches within populations are likely to occur, and to include areas that contain an unknown or unexpressed seed bank, we measured the distance from the centroid of each known occurrence or “patch” to the centroid of the nearest neighboring patch, and found that the average distance between nearest patches was 902 ft (275 m). Therefore, we included additional suitable habitat up to (902 ft (275 m) from known occurrences. Population boundaries are known to fluctuate, so this approach also includes areas into which populations could expand.

Then, we connected areas that were within 1,968 ft (600 m) of each other because this is the distance between populations that could be traversed by important insect pollinators, and this approach allows for genetic exchange and connectivity between populations and reduces fragmentation. As discussed in the PCEs section, known pollinators of
Pentachaeta lyonii
include digger bees, megachilid bees, and andrenid bees. Based on body length, foraging ranges are approximately 1,968 ft (600 m) for digger bees, 492-1,968 ft (150-600 m) for megachilid bees and 853-1,640 ft (260-500 m) for andrenid bees (Gathmann and Tscharntke 2002). We chose 1,968 ft (600 m) as the maximum distance to connect known populations because 1,968 ft (600 m) is the foraging range for digger bees, and megachilid bees, and andrenid bees also fall within this foraging range. Plant communities between these areas would also support insect pollinators, include areas for population boundaries to expand, and may also contain unknown or unmapped populations and/or a seed bank.

When determining final critical habitat boundaries, we made every effort to avoid including developed areas such as buildings, paved areas, and other structures that lack PCEs for
Astragalus brauntonii
and
Pentachaeta lyonii.
Because of their small scale, the maps prepared under the parameters for publication within the
Code of Federal Regulations
may not reflect the exclusion of such developed areas. Any such structures and the land under them inadvertently left inside critical habitat boundaries shown on the maps of this final rule have been excluded by text and are not designated as critical habitat. Therefore, Federal actions limited to these excluded areas would not trigger section 7 consultation, unless they affect the species and/or primary constituent elements in adjacent critical habitat.

We are designating critical habitat in areas that contain sufficient primary constituent elements (PCEs) to support life history functions essential for the conservation of the species. Lands are proposed for designation based on sufficient PCEs being present to support the life processes of the species. Some lands contain all PCEs and support multiple life processes. Some lands contain only a portion of the PCEs necessary to support the particular use of that habitat.

A brief discussion of each area designated as critical habitat is provided in the unit descriptions below. Additional detailed documentation concerning the essential nature of these areas is contained in our supporting record for this rulemaking.

Special Management Considerations or Protections

When designating critical habitat, we assess whether the areas determined to be occupied at the time of listing and containing the PCEs may require special management considerations or protections. As discussed in the listing rule, throughout our proposed rule published on November 10, 2006 (70 FR 68982), and in this final rule, most of the known occurrences of
Astragalus brauntonii
and
Pentachaeta lyonii
occur within the direct vicinity of urban areas and are threatened by direct and indirect effects of habitat fragmentation and loss resulting from urban development. The most significant threat to both species is direct loss of plants from urban development. In addition, indirect effects associated with urban development include habitat fragmentation, which reduces gene flow between sites; reduction in insect pollinators; increases in nonnative plants and animals; and changes in local hydrology that affect plant communities (Conservation Biology Institute 2000).

Known threats to both species include but are not limited to: Weed control such as herbicide application, mowing, and direct removal of plants; increased fire frequencies associated with human activities that contribute to the conversion of native shrubland to grassland; competition from nonnative plant species; and cattle grazing and recreational activities such as off-road vehicle use and equestrian and foot traffic that results in trampling of plants. Other known threats specific to
Astragalus brauntonii
include land use activities that result in frequent disturbances and removal of plants before they replenish the seed bank, such as yearly road maintenance. Other known threats specific to
Pentachaeta lyonii
include soil-disturbing activities such as discing associated with fire suppression activities and changes to

the structure and composition of pocket grassland communities that displace
P. lyonii
(i.e., introduction of nonnative annual grasses, changes in local hydrology, and increased gopher activity). As such, we believe that each area designated as critical habitat may require some level of management and/or protection to address the current and future threats to the species. Threats specific to each unit that may require special management considerations or protection are further discussed in the Unit Descriptions section.

Critical Habitat Designation

We are designating 3,300 ac (1337 ha) within six units as critical habitat for
Astragalus 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, that contain the PCEs and may require special management, and those additional areas that were not known at the time of listing but were found to be essential to the conservation of
A. brauntonii.
With the exception of Units 1 and 3, all areas not known at the time of listing are within the same geographic areas and part of the same populations as those areas known at the time of listing. For reasons described previously (see Criteria Used To Identify Critical Habitat section), we have determined that inclusion of all known locations that still contain the PCEs, including those not known at the time of listing, is essential to the conservation of the species because this species is extremely limited in distribution, has a very small overall population size, and often occurs in very small disjunct populations, making it particularly vulnerable to extinction (Noss
et al.
1997). Inclusion of these populations reduces fragmentation, prevents range collapse of the species, maintains genetic connectivity between populations, and increases the chance of recolonization from neighboring populations if one patch becomes extirpated (Noss
et al.
1997).

Table 1 shows the proposed and final critical habitat units for
Astragalus brauntonii.
Table 2 shows the approximate area designated as critical habitat for
A. brauntonii
by land ownership.

Table 1.—Proposed and Final Critical Habitat Units for Astragalus brauntonii (ac (ha))

Critical habitat units/subunits
County

Proposed rule
(Nov. 10, 2005)
ac (ha)

Final rule
ac (ha)

Unit 1: Northern Simi Hills
Ventura
471 (191)
434 (175)

Subunit 1a

196 (79)
183 (74)

Subunit 1b

80 (32)
73 (29)

Subunit 1c

118 (48)
108 (44)

Subunit 1d

77 (32)
70 (28)

Unit 2: Southern Simi Hills
Ventura/Los Angeles
1,128 (456)
1,019 (414)

Subunit 2a

452 (183)
410 (166)

Subunit 2b

1 (0.5)
1 (0.5)

Subunit 2c

173 (70)
144 (58)

Subunit 2d

121 (49)
111 (45)

Subunit 2e

157 (63)
146 (60)

Subunit 2f

224 (90)
207 (84)

Unit 3: Santa Monica Mountains
Los Angeles
243 (98)
228 (93)

Unit 4: Pacific Palisades
Los Angeles
577 (233)
505 (205)

Unit 5: Monrovia
Los Angeles
331 (134)
282 (114)

Unit 6: Coal Canyon
Orange
889 (360)
832 (336)

Total

3,639 (1,472)
3,300 (1,337)

Table 2.—Approximate Acreage by Land Ownership Categories Within Critical Habitat Units/Subunits for Astragalus brauntonii (ac (ha))

Critical habitat unit and subunit
Federal
State
Local agency
Private
Total

Unit 1: Northern Simi Hills
0 (0)
0 (0)
21 (9)
413 (166) 4
34 (175)

Subunit 1a
0 (0)
0 (0)
19 (8)
164 (66)
183 (74)

Subunit 1b
0 (0)
0 (0)
0 (0)
73 (29)
73 (29)

Subunit 1c
0 (0)
0 (0)
0 (0)
108 (44)
108 (44)

Subunit 1d
0 (0)
0 (0)
2 (1)
68 (27)
70 (28)

Unit 2: Southern Simi Hills
196 (80)
118 (48)
427 (173)
278 (113)
1,019 (414)

Subunit 2a
0 (0)
118 (48)
221 (89)
71 (29)
410 (166)

Subunit 2b
0 (0)
0 (0)
1 (0.5)
0 (0)
1 (0.5)

Subunit 2c
0 (0)
0 (0)
144 (58)
0 (0)
144 (58)

Subunit 2d
111 (45)
0 (0)
0 (0)
0 (0)
111 (45)

Subunit 2e
85 (35)
0 (0)
61 (25)
0 (0)
146 (60)

Subunit 2f
0 (0)
0 (0)
0 (0)
207 (84)
207 (84)

Unit 3: Santa Monica Mountains
172 (70)
0 (0)
0 (0)
56 (23)
228 (93)

Unit 4: Pacific Palisades
0 (0)
439 (178)
0 (0)
66 (27)
505 (205)

Unit 5: Monrovia
0 (0)
0 (0)
218 (88)
64 (26)
282 (114)

Unit 6: Coal Canyon
0 (0)
589 (238)
0 (0)
243 (98)
832 (336)

Total
368 (150)
1,146 (464)
666 (270)
1,120 (453)
3,300 (1,337)

We present brief descriptions of all units, and reasons why they meet the definition of critical habitat for
Astragalus 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 21 ac (9 ha) of local agency land (Rancho Simi Recreation and Parks District) and 413 ac (166 ha) of private lands. It is divided into four subunits mapped from occurrences identified after the time of listing but currently occupied; all occur within 1.5 mi (2.5 km) of each other. Unit 1, inclusive of the four subunits, is located within the same physiographic area (the Simi Hills) as Unit 2. This unit is essential because it represents a previously unknown portion of the species' range north of Unit 2, and inclusion of multiple populations within the entire range increases a species' chance of persistence (Noss
et al.
1997). These subunits are occupied and contain one or more of the PCEs. Threats that may require special management in this unit include road maintenance, which could result in disturbances that are too frequent and prevent replenishment of the seed bank, invasion of nonnative plants 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 19 ac (8 ha) of local agency land in Challenger Park owned by Rancho Simi Recreation and Parks District and 164 ac (66 ha) of private land within dedicated open space managed by the Bridle Path Homeowner's Association. It occurs along Bus Canyon. This subunit contains at least two of the PCEs (2 and 3); whether it contains PCE 1 is unknown. This subunit supports a population as evidenced by three plants observed in three separate locations in 1998.

Subunit 1b:
This subunit consists of 73 ac (29 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 two of the PCEs (2 and 3); whether it contains PCE 1 is unknown. This subunit supports a population of at least three plants observed in 2000.

Subunit 1c:
This subunit consists of 108 ac (44 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 of the PCEs. This subunit supports a population of approximately 66 plants observed in 2004.

Subunit 1d:
This subunit consists of 68 ac (27 ha) of private land owned by Boeing and 2 ac (1 ha) of local agency lands (Santa Monica Mountains Conservancy). This subunit contains at least two of the PCEs (2 and 3); whether it contains PCE 1 is unknown. Several hundred plants were reported at this location after a fire in 2006 (Lopez 2006).

Unit 2: Southern Simi Hills Unit

This unit is located along the southern Simi Hills in Ventura and Los Angeles Counties and consists of 196 ac (80 ha) of Federal lands, 118 ac (48 ha) of State land, 427 ac (173 ha) of local agency lands (Conejo Open Space Conservation Authority (COSCA), City of Thousand Oaks, Santa Monica Mountains Conservancy, and Rancho Simi Recreation and District), and 278 ac (113 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 contain all of the PCEs, provide connectivity between several occurrences known at the time of listing, and represent the southernmost portion of the species' range within the Simi Hills. Inclusion of these subunits reduces fragmentation, maintains genetic connectivity between populations, and increases the chance of recolonization from neighboring populations if one patch becomes extirpated (Noss
et al.
1997). Threats that may require special management in this unit include road and trail maintenance that could result in disturbances that are too frequent and prevent replenishment of the seed bank, invasion of nonnative plants that could crowd out
Astragalus 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 118 ac (48 ha) of State land managed by COSCA, 221 ac (89 ha) of local agency lands designated as open space in Oakbrook Regional Park and owned and managed by COSCA, and 71 ac (29 ha) of private land. This subunit is mapped from occurrences known at the time of listing and it contains all of the PCEs. It includes small numbers of plants found in several locations along a ridge; we believe a seed bank exists within and between known occurrences because the locations are near each other and the habitat is contiguous between them and close enough for genetic connectivity through insect pollination.

Subunit 2b:
This subunit consists of 1 ac (0.5 ha) of local agency land owned by the City of Thousand Oaks. This subunit occurs within a Southern California Edison easement and adjacent to a trail in Conejo Open Space District surrounded by a residential neighborhood. It is mapped from an occurrence identified after listing and it contains all of the PCEs. Despite the small size of the subunit, it likely contains a relatively large population; approximately 68 plants were observed at this location in 2003. The population is enclosed by permanent fencing, and the area receives periodic vegetation clearing for fire control.

Subunit 2c:
This subunit consists of 144 ac (58 ha) of local agency land in Oak Canyon Community Park owned and managed by Rancho Simi Recreation and Parks District. This subunit is mapped from an occurrence known at the time of listing and it contains all of the PCEs. It includes plants found in several locations along both sides of Medea Creek and contains a relatively large area. Approximately 400 plants were observed in this area in 1993, although few plants have been observed since then. This subunit is threatened by additional park development, which may require special management.

Subunit 2d:
This subunit consists of 111 ac (45 ha) of Federal land within the Santa Monica Mountains National Recreation Area. It includes plants that were found at two separate locations on both sides of Palo Comado Canyon, and is mapped from an occurrence known at the time of listing. Fewer than 30 plants were observed in this area in 1987, and fewer than 10 plants at a time have been observed since then, however, the unit continues to remain occupied and contains a seed bank. This subunit contains all of the PCEs.

Subunit 2e:
This subunit consists of 85 ac (35 ha) of Federal land within the Santa Monica Mountains National Recreation Area, and 61 ac (25 ha) of local agency land owned and managed as open space by Santa Monica Mountains Conservancy. This subunit is located on the east side of Cheseboro Canyon in an area that is relatively isolated from urban development. It is mapped from an occurrence identified after listing. Approximately 30 plants were observed at this location in 2000, hundreds of plants were observed

during post-fire surveys in 2006, and this subunit contains all of the PCEs.

Subunit 2f:
This subunit consists of 207 ac (84 ha) of private land located east of the City of Chatsworth along Dayton Canyon in the eastern Simi Hills. It is mapped from one occurrence known at the time of listing and additional occurrences identified since the time of listing, although these occurrences are within the same population. A portion of one of the populations was removed during development in 1999. This subunit contains all of the PCEs. Approximately 14 plants were observed in this area in 1999, and 27 plants were observed during post-fire surveys in 2006.

Unit 3: Santa Monica Mountains Unit

This unit is located in the eastern Santa Monica Mountains in upper Zuma Canyon, north of Point Dume in Los Angeles County. It consists of 172 ac (70 ha) of Federal land within the Santa Monica Mountains National Recreation Area, and 56 ac (23 ha) of private land. It includes an area where more than 300 plants were found in 1999 after a prescribed burn, and the entire unit is mapped from an occurrence identified after listing. This unit contains all of the PCEs, is occupied, is the only known location in the western Santa Monica Mountains, and represents the western edge of the species' range. We also believe this area supports a large seed bank based on the observed post-fire germination that occurred here in 1999. This unit is essential because it represents a previously unknown portion of the species' range, and inclusion of multiple populations within the entire range increases a species' chance of persistence (Noss
et al.
1997). Threats that may require special management in this unit include road maintenance that could result in disturbances that are too frequent, preventing establishment or replenishment of the seed bank.

Unit 4: Pacific Palisades Unit

This unit is located in the Santa Ynez Canyon north of Pacific Palisades in Los Angeles County and consists of 439 ac (178 ha) of State lands within Topanga State Park and 66 ac (27 ha) of private land. It includes plants found in three separate locations that are part of a single population complex, and is mapped from occurrences known at the time of listing. This is thought to be a large population; over 1,000 plants were observed at one of these locations in 1998. That site is cleared annually for a powerline and fuel break, a disturbance that likely causes large numbers of plants to germinate each year. This unit contains all of the PCEs, represents the eastern edge of the species' range within the Santa Monica Mountains, provides connectivity between the three separate locations, is a relatively large good-quality site, and the area likely incorporates a large existing seed bank. Threats that may require special management in this unit include road maintenance that could result in disturbances that are too frequent, preventing establishment or replenishment of the seed bank, and growth of nonnative plants that could crowd out
Astragalus brauntonii
.

Unit 5: Monrovia Unit

This unit is located in the San Gabriel Mountains in the City of Monrovia in Los Angeles County and consists of 218 ac (88 ha) of local agency land owned by the City of Monrovia and managed as open space (Monrovia Wilderness Preserve) and 64 ac (26 ha) of private land. It includes plants found in several locations that are part of a single population complex, and is mapped from an occurrence known at the time of listing. This is a large population; approximately 700 plants were observed in this area in 2004. This unit contains all of the PCEs, represents a unique and disjunct (separated) piece of the species' range, is a relatively large, good-quality site, and the area likely incorporates a large existing seed bank. Threats that may require special management in this unit include maintenance of fire roads, the growth of nonnative plants that could crowd out
Astragalus brauntonii
, and recreation activities such as foot and bicycle traffic, which could result in trampling of plants.

Unit 6: Coal Canyon Unit

This unit is located south of the City of Yorba Linda in Coal Canyon and Gypsum Canyon in Orange County and consists of 589 ac (238 ha) of State land (Chino Hills State Park and California Department of Fish and Game—Coal Canyon Ecological Reserve) and 243 ac (98 ha) of private land. This unit includes plants found in several locations that are part of a large population complex, and is mapped from occurrences known at the time of listing. This population was very small and declining until a fire in 2003, after which more than 5,000 plants were reported. This unit contains all of the PCEs, represents a disjunct portion of the species' range, is a relatively large area isolated from urban development, and provides genetic connectivity between plants found at several locations within the unit. We also believe the s

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A06-9089. Public record. Not legal advice.