# Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Acanthomintha ilicifolia (San Diego thornmint)

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3AE8-19194

## Record

- **Collection:** Federal Register
- **Document type:** Rule
- **Published:** August 26, 2008
- **Citation:** 73 FR 50454

## Text

DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[FWS-R8-ES-2007-0007; 92210-1117-0000-B4]
RIN 1018-AU86

Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for
Acanthomintha ilicifolia
(San Diego thornmint)

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Final rule.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), are designating critical habitat for
Acanthomintha ilicifolia
(San Diego thornmint) under the Endangered Species Act of 1973, as amended (Act). In total, approximately 671 acres (ac) (272 hectares (ha)) of land in San Diego County, California, fall within the boundaries of the critical habitat designation.

DATES:

This rule becomes effective on September 25, 2008.

ADDRESSES:

The final rule, final economic analysis, and map of critical habitat are available on the Internet at
http://www.regulations.gov.
Supporting documentation we used in preparing this final rule will be available for public inspection, by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office, 6010 Hidden Valley Road, Carlsbad, CA 92011; telephone 760-431-9440; facsimile 760-431-5901.

FOR FURTHER INFORMATION CONTACT:

Jim Bartel, Field Supervisor, U.S. Fish and Wildlife Service, Carlsbad Fish and Wildlife Office (see
ADDRESSES
); telephone 760-431-9440; facsimile 760-431-5901. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

It is our intent to discuss only those topics directly relevant to the designation of critical habitat for
Acanthomintha ilicifolia
in this final rule. For more information on the taxonomy, biology, and ecology of
A. ilicifolia,
refer to the final listing rule published in the
Federal Register
on October 13, 1998 (63 FR 54938), and the proposed critical habitat rule published in the
Federal Register
on March 14, 2007 (72 FR 11946). We did not receive any new information pertaining to the species description, life history, distribution, ecology, or habitat of
A. ilicifolia
following the publication of the proposed designation of critical habitat for this species; therefore, please refer to the documents listed above for a complete detailed discussion of this species.

Acanthomintha ilicifolia
is an annual member of the mint family in the genus
Acanthomintha.
This plant ranges in height from 2 to 6 inches (in) (5 to 15 centimeters (cm)) and has white, two-lipped, tubular flowers with rose-colored markings on the lower lip (Jokerst 1993, p. 713). Members of this genus have paired leaves and several sharp, spiny bracts (modified leaves) below whorled flowers.
Acanthomintha ilicifolia
can be distinguished from other members of the genus by its flower, which has hairless anthers and style.

Acanthomintha ilicifolia
usually occurs on heavy clay soils in open areas surrounded by shrubby vegetation. These openings are generally found within coastal sage scrub, chaparral, and native grassland of coastal San Diego County and south to San Telmo in northern Baja California, Mexico (Beauchamp 1986, p. 175; Reiser 2001, pp. 3-5).
Acanthomintha ilicifolia
is frequently associated with gabbro soils, which are derived from igneous rock, and gray calcareous clays derived from soft calcareous sandstone (Oberbauer and Vanderwier 1991, pp. 208-209). This species is endemic to San Diego County, California, and northwestern Baja California, Mexico, and grows on open clay lenses described as friable, meaning that these soils have a loose, crumbly texture.

Previous Federal Actions

On August 10, 2004, the Center for Biological Diversity and California Native Plant Society challenged our failure to designate critical habitat for this species as well as four other plant species (
Center for Biological Diversity
v.
Norton,
C-04-3240 JL (N. D. Cal.)). In a settlement agreement dated December 21, 2004, we agreed to submit for publication in the
Federal Register
a proposed designation of critical habitat, if prudent and determinable, on or before February 28, 2007, and a final determination by February 28, 2008. We published a proposed critical habitat designation for
Acanthomintha ilicifolia
in the
Federal Register
on March 14, 2007 (72 FR 11946). As part of that 2007 proposed designation, we determined that it was prudent to designate critical habitat for this species (72 FR 11946; March 14, 2007). We accepted public comments on the proposed designation for 60 days, ending May 14, 2007.

On November 27, 2007, we published a notice announcing the availability of the draft economic analysis (DEA) and reopening the public comment period on the proposed rule (72 FR 66122). This comment period closed on December 27, 2007. In light of new information received, we requested an extension of the due date of the final critical habitat rule. On April 16, 2008, the extension request was granted allowing us to open an additional comment period. On May 13, 2008, we opened a third comment period on the DEA and the proposed rule. This comment period closed on June 12, 2008 (73 FR 27483). Please refer to the “Previous Federal Actions” section of the proposed critical habitat rule for
Acanthomintha ilicifolia
, which published in the
Federal Register
on March 14, 2007 (72 FR 11946), for a discussion of additional Federal actions that occurred prior to the proposed designation of critical habitat for this species. This final rule complies with the December 21, 2004, settlement agreement and April 16, 2008, extension.

Summary of Comments and Recommendations

We requested written comments from the public on the proposed designation of critical habitat for
Acanthomintha ilicifolia
in the proposed rule that published on March 14, 2007 (72 FR 11946), and in the notice of availability of the draft EA published in the
Federal Register
on November 27, 2007 (72 FR 66122). We received significant information during the second comment period; therefore, we opened a third comment period on the proposed rule and the draft EA. The third comment period opened on May 13, 2008, and closed June 12, 2008 (73 FR 27483). We contacted appropriate Federal, State, and local agencies; scientific organizations; and other interested parties and invited them to comment on the proposed rule and the draft EA.

During the comment period that opened on March 14, 2007, and closed on May 14, 2007, we received two comments directly addressing the proposed critical habitat designation. One comment was from a Federal agency and the other was from a non-governmental organization. During the second comment period open from November 27, 2007 to December 27, 2007, we received four comment letters. Of these latter comments, one was from a Federal agency, one was from a local government, one was from a peer

reviewer, and one was from an organization. We did not receive any additional comments during the third comment period. All comments received were grouped into general issue categories relating to the proposed designation of critical habitat for
Acanthomintha ilicifolia
, and are addressed in the following summary and incorporated into this final rule as appropriate. We did not receive requests for a public hearing or comments on the draft EA.

Peer Review

In accordance with our policy published on July 1, 1994 (59 FR 34270), we solicited expert opinions from five knowledgeable individuals with scientific expertise that included familiarity with the species, the geographic region where the species occurs, and conservation biology principles. We received a response from one peer reviewer. The peer reviewer agreed with our characterization of the known physical and biological features for
Acanthomintha ilicifolia
.

We reviewed all comments we received from the peer reviewer and the public for substantive issues and new information regarding critical habitat for
Acanthomintha ilicifolia
. The comments are addressed in the following summary.

Peer Reviewer Comments

Comment 1:
The peer reviewer concurred with our characterization of the known physical and biological features that are essential to the conservation of this species based on extensive research on
Acanthomintha ilicifolia
. Additionally, the peer reviewer highlighted several areas of interest that have not been studied at this time, but may provide more information on the physical and biological features essential for the survival of
A. ilicifolia
. The topics that the peer reviewer indicated require further research include population genetics, pollinator studies, and additional soil studies. The peer reviewer stated that additional population genetics studies of
A. ilicifolia
could show that some populations display greater genetic diversity, or that some genetic characters are contained in only one or two populations. Additionally, the peer reviewer indicated that studies are needed to determine habitat requirements for pollinators and to understand the effect that habitat fragmentation may have on
A. ilicifolia
.

Our Response:
We agree with the peer reviewer's assessment of information needs for
Acanthomintha ilicifolia
. We used the best available scientific and commercial data to designate critical habitat for this species. The peer reviewer's comments support the designation, and the peer reviewer did not identify any significant data that we did not consider. We look forward to working with stakeholders, researchers, and other organizations to study the important issues identified by the peer reviewer. The California Department of Fish and Game is funding a study on the pollinators of
A. ilicifolia
. This and other future projects will help us to better understand the conservation needs of this species.

Comment 2:
The peer reviewer applauded and reiterated the importance of our inclusion of newly discovered populations of
Acanthomintha ilicifolia
in the proposed critical habitat. The peer reviewer also commented that our criterion for population stability is reasonable and further tracking of population dynamics may help refine this criterion. The peer reviewer supported our inclusion of up to 500 ft (152 m) of habitat adjacent to mapped occurrences where the habitat is contiguous with occupied habitat and supports the physical and biological features essential to the conservation of this species. The peer reviewer indicated these areas capture unmapped clay soil patches, minimize the effects of fragmentation, and help alleviate our lack of specific knowledge regarding pollinators for this species by minimizing the encroachment of irrigated areas that support nonnative insect fauna (which may compete with native insect pollinators or affect the hydrology that supports
A. ilicifolia
).

Our Response:
We appreciate the peer reviewer's positive evaluation of our criteria used to identify critical habitat.

Comment 3:
The peer reviewer commented that we should not exclude the area within the pending Encinitas subarea plan under the Multiple Habitat Conservation Plan (MHCP) as proposed. The peer reviewer indicated this plan has not progressed towards completion at a timely rate and that until a conservation plan has been developed, we should designate the area as critical habitat.

Our Response:
Following the publication of the proposed rule, we reevaluated the City of Encinitas' pending habitat conservation plan (HCP) subarea plan under the MHCP in San Diego County, California. We concluded that, at this time, the City of Encinitas' subarea plan is not complete and progress on the completion has slowed. However, the majority of subunit 1C is part of the Manchester Avenue Mitigation Bank and is actively managed for
Acanthomintha ilicifolia
(Spiegelberg 2005, p. 1-33). Preservation and management of the Manchester Avenue Mitigation Bank is independent of the completion of the City of Encinitas' subarea plan. We determined that the benefits of excluding the lands within the Manchester Avenue Mitigation Bank outweigh the benefits of including these lands in a critical habitat designation and that their exclusion will not result in extinction of this species. Therefore, we excluded 70 ac (28 ha) of subunit 1C under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion), and we designated the remaining 9 ac (4 ha) of private lands outside the Manchester Avenue Mitigation Bank as critical habitat.

Public Comments

Comment 4:
One commenter stated that at a minimum, all occupied habitat needs to be designated as critical habitat. The commenter stated the definitions of “recovery” and “conservation” are synonymous, and therefore, any critical habitat designation must include all areas the Service finds essential to the conservation (i.e., recovery) of the species. This commenter reiterated that
Acanthomintha ilicifolia
is widely scattered in a discontinuous distribution, and stated that this type of distribution can lead to a high level of within-species genetic diversity. The commenter stated that it is essential to conserve within-species diversity represented by occurrences on varying soil types as well as geographically distinct populations. The commenter stated that within-species diversity helps species preserve their ability to respond to diseases, climate change, pollution, and other current and future threats. The commenter concluded that in the face of uncertainty, designation of all occupied habitat, regardless of ownership, is legally necessary to conserve this species.

Our Response:
We agree with the commenter that the term conservation is defined in the Act as using all methods and procedures necessary to bring any listed species to the point at which the measures provided under the Act are no longer necessary (i.e., recovery). The provisions within section 4 of the Act require the Secretary to determine whether a species is endangered or threatened based on threats to the species, and therefore, recovery is linked to the alleviation of threats to the species.

The Act defines critical habitat as the specific areas within the geographical area occupied by the species at the time it is listed on which are found those physical and biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection; and specific areas outside the geographical area occupied by the species at the time it is listed upon a determination by the Secretary that such areas are essential for the conservation of the species. We believe that our proposed and final designations accurately capture all areas essential to the conservation of
Acanthomintha ilicifolia
as required by the Act. The areas delineated as critical habitat in this final rule: (1) Support populations that occur on rare or unique habitat within the species' range; (2) support the largest known populations of
A. ilicifolia
; and (3) support the most stable populations of
A. ilicifolia
. Further, this final designation identifies threats to the physical and biological features essential to the conservation of the species within each subunit and identifies special management considerations or protection needed to alleviate those threats and thereby will contribute to the recovery of
A. ilicifolia
. Although there is no recovery plan for this species, we believe that recovery for
A. ilicifolia
can be achieved through the implementation of conservation measures to protect the physical and biological features on the areas occupied by this species that meet the definition of critical habitat (see the “Special Management Considerations or Protection” section for details about the type of management needed for this species).

The commenter stated that we need to include all occupied habitat in order to conserve the species' geographic and genetic diversity. Species and plant communities that are protected across their ranges are expected to have lower likelihoods of extinction (Soule and Simberloff 1986; Scott
et al.
2001, pp. 1297-1300); our criteria identified multiple locations across the entire range of the species as essential habitat to prevent range collapse. Genetic variation in plants can result from the effects of population isolation and adaptation to locally distinct environments (Lesica and Allendorf 1995, pp. 754-757; Fraser 2000, pp. 49-51; Hamrick and Godt 1996, pp. 291-295); and our criteria identified populations that occur on rare or unique habitat within the species' range in order to capture the range of plant communities, soil types, and environmental gradients in which
Acanthomintha ilicifolia
is found to preserve the genetic variation that may result from adaptation to local environmental conditions, as documented in other plant species (e.g., see Hamrick and Godt 1996, pp. 299-301; Millar and Libby 1991, pp. 150, 152-155). Locations that possess unique ecological characteristics are those that represent the full range of environmental variability where
A. ilicifolia
have evolved, and, therefore, are likely to promote the adaptation of this species to different environmental conditions. We believe we captured the within-species diversity that the commenter is referring to by including areas that support populations on rare or unique habitat types, the largest known populations of
A. ilicifolia
, and the most stable populations of
A. ilicifolia
. At this time, no one has investigated the genetic structure of this species; however, if such genetic studies are conducted for this species in the future, we may revise this critical habitat designation if we determine that this final designation does not adequately represent the species' range of genetic diversity.

Our designation relies on the best available scientific information to capture the geographic range of the species. The commenter did not specifically identify any geographically distinct populations that we did not capture in our designation. Our criteria do not capture populations where we had information indicating that the habitat had been lost to development and, therefore, the populations were likely extirpated. Furthermore, our criteria limited the designation to areas where we had data indicating the location of a known population and demographic or specific habitat data to assess its importance to the overall conservation of this species. As described above, our designation includes areas that support populations of
Acanthomintha ilicifolia
on rare or unique habitat types, the largest known populations of
A. ilicifolia
, and the most stable populations of
A. ilicifolia
, thereby capturing species' diversity. We determined that designating these areas, each of which was occupied at the time of listing and contains the physical and biological features essential to the conservation of
A. ilicifolia
fulfills the plant's biological needs and is adequate to conserve this species (for a more detailed discussion see the “Criteria Used To Identify Critical Habitat” section). We concluded that there are no areas outside the geographical area occupied by the species at the time of listing essential to the conservation of the species and, therefore, consistent with section 3(5)(c) of the Act, we did not include the entire geographical area currently occupied by this species.

We recognize that our designation does not encompass all known occurrences of this species; however, we believe that our criteria and the designation are adequate to provide for the conservation and recovery of this species throughout its extant range. Although there is no recovery plan for this species, we believe that recovery for
A. ilicifolia
can be achieved through the implementation of conservation measures to protect the physical and biological features in the areas occupied by this species that meet the definition of critical habitat (see the “Special Management Considerations or Protection” section for details about the type of management needed for this species).

The commenter expressed concern that the proposed designation may not capture all areas necessary to allow
Acanthomintha ilicifolia
to respond to diseases, climate change, pollution, and other current and future threats. As stated above, the designation identifies all known threats to the physical and biological features essential to the conservation of the species in each individual subunit and identifies special management considerations or protection needed to alleviate those threats. We recognize these threats may change in the future; however, we base our critical habitat designations on the information available at the time of the designation and do not speculate as to what areas may be found essential if better information became available or what areas may become essential over time. The commenter did not include any specific data on future threats to the features essential to this species nor are we aware of any studies that include additional information that we did not consider. Should additional data become available concerning future threats, we may revise this critical habitat designation if it is determined that the designation did not capture an area essential to the conservation of the species based on the identification of additional threats.

Comment 5:
One commenter stated that the Act specifically allows critical habitat designations to include areas both within and outside the geographical area occupied by the species at the time it is listed as well as currently unoccupied habitat in order to capture all areas essential to the recovery of listed species. The commenter continued to state that the proposed designation of critical habitat

for
Acanthomintha ilicifolia
fails to meet the government's legal requirements to promote recovery of
A. ilicifolia
.

Our Response:
We agree with the commenter that the Act does provide the flexibility to include areas within the designation that were not occupied at the time a species was listed (including currently unoccupied habitat) if those areas are determined to be essential to the conservation of the species. We evaluated all known occurrences of
Acanthomintha ilicifolia
for inclusion in our proposed critical habitat designation and identified two subunits in the proposed rule, 3E and 4D, for inclusion in the designation that were not known to be occupied at the time the species was listed. We now consider subunits 3E and 4D to be occupied at the time of listing. Even though these occurrences were not discovered until after the species was listed in 1998, over 1,000 plants were recorded at each of these sites when they were first discovered. We believe the large population size indicates that the occurrences were established for several years because the seeds of
A. ilicifolia
do not disperse in large numbers and any new population of
A. ilicifolia
would likely start out small and take several years to reach a population size greater than 1,000 plants. In our proposed rule, we did not identify any areas outside the geographical area occupied by
A. ilicifolia
as essential for the conservation of this species. As discussed in response to comment 4, we believe our proposed rule and this final designation of critical habitat meet the requirements of the Act and are consistent with 50 CFR 424.12(e). We are not designating any areas outside the geographical area occupied by this species as we believe this designation is adequate to ensure the conservation of the species.

We recognize the designation of critical habitat may not include all habitat areas that may eventually be determined to be necessary for the species' recovery. Critical habitat designations do not signal that habitat outside the designation is unimportant or may not be required for recovery. Areas outside the critical habitat designation will continue to be subject to conservation actions implemented under section 7(a)(1) of the Act and regulatory protections afforded by the section 7(a)(2) jeopardy standard and the prohibitions of section 9 of the Act. Critical habitat designations based on 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.

Comment 6:
One commenter stated that the proposed exclusions, which if finalized will exclude over 67 percent of occupied habitat, violate the principles of the Act, and are not legal because excluding areas from a critical habitat designation will not promote the recovery of this species as is required by the Act. The commenter noted that, because all the units identified in the proposed rule are described as requiring special management considerations to conserve the primary constituent elements, that all units must be designated.

Our Response:
Section 4(a)(3)(A) of the Act generally mandates that the Secretary designate any habitat which is considered to be critical habitat, as defined in section 3(5)(A), concurrently with listing and provides that such designations may be revised thereafter as appropriate. Section 4(b)(2) of the Act further requires that in making critical habitat designations, the Secretary take into account the economic impact, the impact on national security, and any other relevant impact of specifying any particular area as critical habitat. The Secretary may exclude any area from critical habitat if he determines that the benefits of exclusion outweigh the benefits of specifying such area as part of the critical habitat, unless he determines that the failure to designate such area as critical habitat will result in the extinction of the species concerned. Therefore, consistent with the Act, we must consider the relevant impacts of designation on those areas that are determined to meet the definition of critical habitat using the best scientific data available prior to finalizing a critical habitat designation.

After determining all areas that meet the definition of critical habitat under section 3(5)(A) of the Act, we considered the economic impact, the impact on national security, and other relevant impacts of specifying any particular area as critical habitat. In this final designation, we recognize that designating critical habitat in areas where we have partnerships with landowners that have led to conservation and management of
Acanthomintha ilicifolia
on non-Federal lands has a relevant perceived impact to those landowners and a relevant impact to future partnership and conservation efforts on non-Federal lands. Based on these relevant impacts, we evaluated the benefits of designating those particular areas as critical habitat against the benefits of excluding the areas from the designation, and we determined that the benefits of excluding a portion of subunits 1A and 1C and all of subunits 1B, 2A, 2B, 2C, 2D, 3A, 3B, 4A, 4B, 4C, and 4D outweigh the benefits of including these areas in the final critical habitat designation and that the exclusion of these areas will not result in extinction of this species. Therefore, these exclusions are in full compliance with the Act. We also concluded that the conservation and management that will occur on the non-Federal lands we are excluding will contribute to the recovery of this species even though the Act does not require that areas excluded from a critical habitat designation contribute to recovery of a species, but rather that the benefits analysis demonstrate that the benefits of exclusion outweigh the benefits of inclusion and that the exclusion will not result in the extinction of the species. For a complete analysis and discussion of the exclusions, please refer to the “Exclusions Under Section 4(b)(2) of the Act” section below.

Comment 7:
One commenter specifically questioned the ability of the San Diego Multiple Habitat Conservation Program (MHCP) and the San Diego Multiple Species Conservation Program (MSCP) to prevent extinction of this species, therefore questioning our determination that excluding these areas would not lead to the extinction of
Acanthomintha ilicifolia
. The commenter stated that habitat conservation plans (HCPs), like the MHCP and MSCP, are often ineffective conservation vehicles. The commenter listed three studies and stated that the studies conclude that species covered by multiple-species HCPs may be less likely to be recovered than those outside such HCPs. The commenter goes on to state that the MHCP and MSCP are in relatively early stages of implementation and are untested. The commenter states there are substantial questions as to whether these HCPs will provide sufficient habitat or species conservation for
A. ilicifolia
. The commenter stated that designating critical habitat in areas covered by the MHCP and MSCP would not undermine those HCPs and that the additional protection that a critical habitat designation provides would be especially beneficial if project proponents in those areas elect not to follow the guidelines set forth in the HCPs, suggesting that designating critical habitat would provide a useful and needed “safety net.” The commenter requested that we reconsider

our proposed exclusion of non-Federal lands covered by the MHCP and MSCP.

Our Response:
We reevaluated our proposed exclusions of non-Federal land covered by the MHCP and MSCP. Although the commenter grouped the two HCPs together, we evaluated the proposed exclusion of each HCP separately in relation to the comments.

We reevaluated our proposed exclusion of non-Federal land covered by the MHCP under the approved Carlsbad Habitat Management Plan (HMP) and the draft Encinitas subarea plan. The MHCP is a framework plan that has been in place for 5 years and is structured to be implemented through the approval of individual, constituent subarea plans.

The City of Carlsbad received an incidental take permit based on the Carlsbad HMP, an individual subarea plan under the MHCP framework plan on November 9, 2004. All 59 ac (24 ha) of land that meet the definition of critical habitat within the boundaries of the Carlsbad HMP are already conserved under the Carlsbad HMP. In addition to the two areas that we proposed as critical habitat in the Carlsbad HMP, there are other populations of
A. ilicifolia
that are conserved under the subarea plan. Not all areas placed in conservation are actively managed under the plan at this time; however, we believe the Carlsbad HMP conserves
A. ilicifolia
within its boundaries. According to the Service's biological opinion for the Carlsbad HMP, coverage of
Acanthomintha ilicifolia
under this plan is contingent upon compliance with the conservation measures outlined in the HMP (i.e., a funded management plan in place) and the completion of the San Marcos subarea plan under the MHCP. However, we did not identify any lands in San Marcos that meet the definition of critical habitat as described in the “Criteria Used to Identify Critical Habitat” section. As a result, we analyzed the exclusion of subunits 1A and 1B in more detail and concluded that exclusion is appropriate because the essential habitat under the Carlsbad HMP is conserved. Management plans were developed and are being implemented for conserved lands in both of these subunits, although some management differs between these two areas because these management plans were developed over different periods of time (i.e., the management plan for subunit 1A was developed after the Carlsbad HMP was completed, whereas the management plan for lands within subunit 1B was developed prior to development of the Carlsbad HMP). Regardless, conservation and management of
A. ilicifolia
in these subunits is occurring and we believe it is contributing to the conservation of the species. Overall, the extent of habitat preservation and management that has taken place through implementation of the Carlsbad HMP since it was permitted in 2004 is significant, and demonstrates the City of Carlsbad's commitment to fully implement this HCP.

A detailed accounting of preservation, conservation, and management requirements of the Carlsbad HMP can be found in the “Exclusions Under Section 4(b)(2) of the Act” section. The comprehensive framework of the subarea plan and area-specific management plans developed as areas are preserved under the subarea plan contain requirements to conserve and adaptively manage
Acanthomintha ilicifolia
habitats and provide for the conservation of this species' primary constituent elements (PCEs), thereby contributing to the recovery of this species. The Carlsbad HMP provides for management and monitoring for
A. ilicifolia
at several sites, including habitat in subunit 1A that is currently actively managed by the Center for Natural Lands Management. Activities that benefit
A. ilicifolia
in subunit 1A include mapping and census projects, removal of nonnative invasive species, and the restoration of areas degraded by past human use (Tierra Data, Inc. 2005, p. 34-63; Carlsbad HMP 2004, p. D-97). Land in subunit 1B was permanently preserved prior to the creation of the HMP. Management of the conserved land in subunit 1B is the responsibility of the homeowners' associations who own the open space in this subunit. These lands are signed and fenced and considered part of Carlsbad's habitat preserve.

The Encinitas subarea plan under the MHCP is not complete, and significant progress has not occurred towards its completion. Therefore, we are not excluding from the final designation essential habitat within the draft Encinitas subarea plan.

We also reevaluated our proposed exclusion of non-Federal land covered by approved subarea plans under the MSCP. The MSCP is a framework plan that has been in place for 10 years. Both the City and the County of San Diego received incidental take permits for their individual subarea plans under the MSCP framework plan. Approximately 948 ac (383 ha) of land that meet the definition of critical habitat are within the City and County subarea plan boundaries under the MSCP. The MSCP subarea plans provide for the conservation of
Acanthomintha ilicifolia
through the establishment of preserve lands within the Multi-Habitat Planning Area (MHPA) (City) and Pre-Approved Mitigation Areas (PAMA) (County). In 10 years of implementing the subarea plans, approximately 787 ac (319 ha), or 83 percent, of lands that meet the definition of critical habitat are conserved. Although some areas placed in conservation are not yet fully managed under the plans, we believe the subarea plans under the MSCP will conserve essential habitat of
A. ilicifolia within the subarea plan boundaries.
The extent of habitat preservation and management that has taken place through implementation of the MSCP subarea plans is significant, and demonstrates the City's and County's commitments to fully implement their subarea plans.

The commenter indicated concern that species may more likely recover outside of HCPs and questioned the habitat and species conservation provided by the MSCP for
Acanthomintha ilicifolia.
The subarea plans under the MSCP contain requirements to monitor and adaptively manage
A. ilicifolia
habitats and provide for the conservation of this species' PCE. The framework and area-specific management plans required under the subarea plans are comprehensive and address a broad range of management needs at the preserve and species levels that are intended to reduce the threats to covered species and thereby contribute to the recovery of the species. These plans include the following: (1) Fire management; (2) public access control; (3) fencing and gates; (4) ranger patrol; (5) trail maintenance; (6) visitor/interpretive and volunteer services; (7) hydrological management; (8) signage and lighting; (9) trash and litter removal; (10) access road maintenance; (11) enforcement of property and/or homeowner requirements; (12) removal of invasive species; (13) nonnative predator control; (14) species monitoring; (15) habitat restoration; (16) management for diverse age classes of covered species; (17) use of herbicides and rodenticides; (18) biological surveys; (19) research; and (20) species management conditions (MSCP 1998).

Eight major populations of
Acanthomintha ilicifolia
are included within preserve lands under the approved MSCP subarea plans, each of which will be conserved from 80 to 100 percent, with 85 percent overall coverage. A detailed accounting of preservation, conservation, and management requirements can be found in the “Exclusions Under Section 4(b)(2) of the Act” section. In sum, all but 89 ac (36 ha) of the total 948 ac (383 ha)

of lands that meet the definition of critical habitat within the MSCP plan area are conserved or otherwise assured of conservation. Consistent with the narrow endemics requirements of the MSCP, the remaining 89 ac (36 ha) will be surveyed for
A. ilicifolia
prior to any development occurring on these lands. Under the City of San Diego's subarea plan, impacts to narrow endemic plants, including
A. ilicifolia,
inside the MHPA will be avoided and outside the MHPA will be protected by: (1) Avoidance; (2) management; (3) enhancement; and/or (4) transplantation to areas identified for preservation (City of San Diego 1997, p. 105-106; Service 1997, p. 15). Under the County of San Diego's subarea plan, narrow endemic plants, including
A. ilicifolia,
will be conserved under the Biological Mitigation Ordinance using a process that: (1) Requires avoidance to the maximum extent feasible; (2) allows for a maximum 20 percent encroachment into a population if total avoidance is not feasible; and (3) requires mitigation at the 1:1 to 3:1 (in kind) for impacts if avoidance and minimization of impacts would result in no reasonable use of the property (County of San Diego (BMO) 1997, p. 11; Service 1998, p. 12). These measures will ameliorate any habitat loss within the 89 ac (36 ha) of lands that are not currently preserved or otherwise assured of conservation under the MSCP, by requiring in situ conservation or mitigation of impacts to
A. ilicifolia and its habitat.
Although some losses may occur to this species, the preservation, conservation, and management of
A. ilicifolia
required under the City and County MSCP subarea plans ensures the long-term conservation of this species and its habitat within the plan areas.

We evaluated the relevant impacts of designating critical habitat within areas covered by the City and County MSCP subarea plans and determined that the benefits of excluding non-Federal lands covered by the MSCP outweigh the benefits of specifying those areas as critical habitat and determined that excluding these lands will not lead to the extinction of
Acanthomintha ilicifolia.
Therefore, we excluded all non-Federal lands covered by the City and County subarea plans under the MSCP from this final designation (please see “Exclusions Under Section 4(b)(2) of the Act” section below for a detailed analysis).

The commenter also expressed concern that HCPs are ineffective conservation vehicles. We respectfully disagree. Numerous processes are incorporated into HCPs that provide for Service oversight of implementation to ensure compliance with the provisions to protect
Acanthomintha ilicifolia.
For example, the MSCP imposes annual reporting requirements and provides for Service review and approval of proposed subarea plan amendments and preserve boundary adjustments and for Service review and comment on projects during the California Environmental Quality Act review process. The Service also chairs the MSCP Habitat Management Technical Committee and the Monitoring Subcommittee (MSCP 1998, p. 5-11—5-23). The Carlsbad HMP also incorporates many processes to ensure the Service an active role in implementation of the HCP. For example, Habitat Management Plans, reviewed and approved by the Service, must be developed for each preserve area within the Carlsbad HMP, and monitoring and management objectives must be established for each preserve. Progress towards meeting these objectives is measured through the submission of annual reports. There are also regular coordination meetings between the Service and the City of Carlsbad to discuss on-going conservation issues. Both the MSCP subarea plans and the Carlsbad HMP must account annually for the progress they are making in assembling conservation areas. The Service must receive annual reports that include, both by project and cumulatively, the habitat acreage destroyed and conserved within the HCPs. This accounting process ensures that habitat conservation proceeds in rough proportion to habitat loss and in compliance with the MSCP subarea plans and, the Carlsbad HMP, and the plans' associated implementing agreements.

The commenter did not provide copies of the citations that they stated conclude that multi-species HCPs are not likely to contribute to the recovery of listed species, nor did the commenter identify any examples of projects that may not comply with the Carlsbad HMP or the City and County MSCP subarea plans by impacting
Acanthomintha ilicifolia.
In light of our summary above, we continue to believe that implementation of the Carlsbad HMP and the City and County MSCP subarea plans will benefit
A. ilicifolia
recovery, and we believe there is adequate oversight of these plans to ensure compliance.

Comment 8:
One commenter supported our exclusion of lands covered by the MSCP and requested that we exclude proposed critical habitat areas within the pending North County MHCP in San Diego County. The commenter stated that the designation of critical habitat in these areas may have a negative effect on entities pursuing the MHCP and deter the completion of the plan.

Our Response:
At this time, the HCP for northern San Diego County (North County MHCP) is being developed and a draft plan is not available for public review. We understand the commenters' concern that a designation of critical habitat in areas that may be addressed in the future by the North County MHCP may have a negative effect on entities pursuing the HCP and deter its completion. This concern is consistent with our discussion of conservation partnerships in the “Exclusions Under Section 4(b)(2) of the Act” section of this final rule. However, we also recognize that there is a regulatory and recovery benefit to designating critical habitat in areas that are not protected through existing management or conservation plans. Exclusions under section 4(b)(2) of the Act must be considered on a case-by-case basis. Because a draft of the northern San Diego County MHCP has not been released for public comment or formally evaluated by the Service, it is not clear that this framework plan will adequately address the conservation and recovery needs of
Acanthomintha ilicifolia.

Nor is it clear
which areas will actively develop subarea plans under the North County MHCP. Therefore, we cannot presently determine that the regulatory and recovery benefits of a critical habitat designation in these areas would be minimized by the measures provided under this future plan. Therefore, we did not exclude lands that may be covered under this plan from critical habitat (the portion of subunit 1A owned by the County of San Diego). However, if this designation is revised in the future, we will re-evaluate for potential exclusion areas conserved under the plan. In the meantime, we are committed to continue working with all partners to the North County MHCP to minimize any additional regulatory burden attributable to this critical habitat designation.

Comment 9:
One commenter questioned discussion in the proposed rule concerning critical habitat designations and public perceptions, stating that we did not present any empirical or quantitative evidence to support our claim that landowners fear a decline in property value due to real or perceived restrictions on land-use options and that participants in pending HCPs or other conservation plans may abandon the planning process in part due to perceived additional regulatory compliance with a critical habitat designation. The commenter noted that the MSCP and MHCP and their

respective subarea plans were presumably approved only after a public education program that would have explained the consequences of having listed species on private property. The commenter further stated that if the MSCP and MHCP function as promised by the proposed rule, critical habitat designation should create few or no additional burdens for permittees and finally that the Service inappropriately considers an exclusion as an “either-or” situation with regard to HCP implementation. The commenter stated that critical habitat and habitat conservation plans can coexist.

Our Response:
The proposed designation cites several studies that have examined the issue of conservation of threatened and endangered species on private lands to support our discussion of the impacts to non-Federal landowners (Wilcove
et al.
1996; Bean 2002; Conner and Mathews 2002; James 2002; Koch 2002; Brook
et al.
2003). As discussed in detail in the “Conservation Partnerships on Non-Federal Lands” section below, at least 80 percent of endangered or threatened species occur either partially or solely on private lands (Crouse
et al.
2002). Although many non-Federal landowners derive satisfaction from contributing to listed species recovery, many private landowners are wary of the possible consequences of attracting endangered species to their property. Mounting evidence suggests that some regulatory actions by the Federal Government, while well-intentioned and required by law, can (under certain circumstances) have unintended negative consequences for the conservation of species on private lands (Wilcove
et al.
1996; Bean 2002; Conner and Mathews 2002; James 2002; Koch 2002; Brook
et al.
2003). Many landowners fear a decline in their property value due to real or perceived restrictions on land-use options where threatened or endangered species are found (Main
et al.
1999; Brook
et al.
2003). According to some researchers, the designation of critical habitat on private lands significantly reduces the likelihood that landowners will support and carry out conservation actions (Main
et al.
1999; Bean 2002; Brook
et al.
2003). Such voluntary conservation actions may be particularly important for listed plant species that are not subject to the take prohibition under section 9 of the Act or the incidental take permitting requirements of section 10(a)(1)(B) of the Act. For this reason, we actively encourage participants developing HCPs under section 10 of the Act to include measures that address the conservation of listed plant species in their plans even though such measures are not required. Designating critical habitat for plant species on lands voluntarily protected in an HCP or other conservation management plan could undermine our efforts. Therefore, we believe the judicious use of excluding specific areas of non-federally owned lands from critical habitat designations can contribute to species recovery and provide a superior level of conservation than critical habitat alone.

Furthermore, our proposed critical habitat designations often draw significant public comment on the real and perceived impacts of the designation to Federal and non-Federal landowners. We received significant comments on multiple rules concerning impacts to private and non-Federal lands covered by HCPs and other land management conservation plans, including comment on this rule stating that the designation of critical habitat in areas covered by HCPs may have a negative effect on entities pursuing an HCP and may deter the completion of pending subarea plans under either the MSCP or MHCP (see Comment 8). As discussed in response to Comment 7 above and in the “Conservation Partnerships on Non-Federal Lands” section below, we continue to recognize that designating critical habitat in areas where we have partnerships with landowners that have led to conservation or management of listed species on non-Federal lands has a relevant perceived impact to landowners and a relevant impact to future partnership and conservation efforts on non-Federal lands.

Finally, we agree with the commenter that implementing a signed and permitted HCP is not an “either-or” situation when determining whether to designate an area that meets the definition of critical habitat as critical habitat. Rather, as stated in section 4(b)(2) of the Act, the Secretary shall designate critical habitat, or make revisions thereto, on the basis of the best available data
and after
(emphasis added) taking into consideration the economic impact, the impact on national security, and any other relevant impact, of specifying any particular area as critical habitat. The Secretary may exclude an area from critical habitat if he determines that the benefits of such exclusion outweigh the benefits of specifying such area as part of the critical habitat. We agree with the commenter that designation of an area covered by an HCP should create few or no additional regulatory burdens for permittees, and our analyses of the benefits of including areas covered by an HCP demonstrates how the regulatory benefit of inclusion is small. And while we agree that critical habitat and habitat conservation plans can coexist, we recognize that the designation has a relevant real impact to future partnerships and conservation efforts on non-Federal lands and a perceived impact to those landowners already in partnership with us. We consider that impact in weighing the benefits of inclusion against the benefits of exclusion on a case-by-case basis to determine if exclusion of those lands is appropriate.

Comment 10:
One commenter objected to the discussion in the proposed rule concerning the inundation of lawsuits relative to critical habitat and suggested that litigation would be unnecessary or unsuccessful if the Service complied with the law. The commenter suggested that policymakers make choices that avoid compliance with the Act's critical habitat requirements and underfund species and habitat conservation programs, starving the Service of funds and staff. The commenter concluded that compliance with the law would be a more fiscally, biologically, and legally responsible choice.

Our Response:
We removed the discussion of litigation-driven workload from this final rule. We believe this final rule is scientifically sound and compliant with the Act and our implementing regulations.

Comment 11:
One commenter indicated that portions of subunit 1A are developed or used for agriculture and do not have the potential to support
Acanthomintha ilicifolia
. The commenter provided a map depicting the areas they believe do not support this species and requested that we remove these lands from critical habitat.

Our Response:
We reassessed the areas described by the commenter. We removed the lands in subunit 1A that do not contain the PCE, including active agricultural fields, navigational aids associated with McClellen-Palomar Airport, a dirt maintenance road, and development areas in the City of Carlsbad. We remapped the boundary of subunit 1A, and verified that the revised subunit contains the features essential to the conservation of species which may require special management considerations or protection. As a result of the changes described above, we removed 26 ac (11 ha) that do not support
A. ilicifolia
and do not contain the PCE, resulting in 62 ac (25 ha) designated as critical habitat within subunit 1A.

Comment 12:
One commenter provided information on the management of lands owned by the

Center for Natural Lands Management (CNLM). The commenter indicated that portions of subunits 1A and 1C are owned by the CNLM, and are managed and monitored for
Acanthomintha ilicifolia
on an annual basis. Funding for the perpetual management of these sites is obtained from a monetary endowment. The CNLM prepared a Property Analysis Record (PAR) to determine how much money is needed to manage and monitor
A. ilicifolia
on these lands. The commenter indicated that the CNLM reduces the threats to
A. ilicifolia
by managing weeds, erecting fences, closing trails, and distributing educational literature to the public. Additionally, the commenter indicated that high school students are involved with annual monitoring for this species and that an entomologist is working to determine potential pollinators for
A. ilicifolia
on lands in subunit 1C.

Our Response:
We appreciate the detailed information provided by the commenter, and we incorporated this information as appropriate into the final rule.

Comments From Other Federal Agencies

Comment 13:
The U.S. Forest Service (USFS) commented that laws, regulations, policies, and current Land Management Plan (LMP) direction currently in place provide protection at least equivalent to the protection that critical habitat designation would provide. The agency stated that the LMP in place at the Cleveland National Forest (CNF) incorporates management direction that provides sufficient protection and management for
Acanthomintha ilicifolia
and its habitat, and that the section 7 consultation on the LMP resulted in the Service coming to a similar conclusion, resulting in the issuance of a non-jeopardy biological opinion. Additionally, the Cleveland National Forest (CNF) has a Species Management Guide for
A. ilicifolia
that provides for exclusion of grazing, recreation, development, and soil disturbance (USFS 1991). The USFS commented that due to management and conservation standards, there should not be any reason to adversely modify the habitat's primary constituent elements for
A. ilicifolia
on the CNF. Furthermore, they commented that designation of critical habitat on CNF lands would not provide any additional benefit to the conservation of the species or its habitat since all site-specific projects proposed by the CNF are subject to section 7(a)(2) consultation with the Service and that designation would unnecessarily add to their analysis burden by requiring CNF to make a determination of effect regarding critical habitat when consulting under section 7 of the Act. The USFS acknowledged their responsibility to conserve and recover listed species and that they will continue to provide necessary management, regardless of critical habitat designation.

Our Response:
We determined that the lands identified on the CNF contain the physical and biological features essential to the conservation of
Acanthomintha ilicifolia
and meet the definition of critical habitat (see “Criteria Used to Identify Critical Habitat” section below). We acknowledge that the LMP for CNF will benefit
A. ilicifolia
and its habitat, and that the CNF has completed many of the actions outlined in the 1991 Management Guide (USFS 1991) to avoid and minimize impacts to
A. ilicifolia
. The LMP contains general provisions for conservation of this species and the Management Guide suggests specific management and conservation actions that should address known threats to this species on USFS lands. However, the LMP is a guidance document and does not require or assure funding for management actions outlined in the plan. Additionally, the LMP does not preclude projects from occurring outside of the framework of the plan that could negatively impact areas designated as critical habitat.

The Secretary has the discretion to exclude an area from critical habitat under section 4(b)(2) of the Act after taking into consideration the economic impact, the impact on national security, and any other relevant impact if he determines that the benefits of such exclusion outweigh the benefits of specifying such area, unless he determines that the exclusion would result in the extinction of the species concerned. We considered the request from the USFS that we exclude their lands because it would unnecessarily add work in the future to determine the effect regarding critical habitat for actions on their lands and the fact that they already completed consultation under Section 7(a)(2) of the Act on the LMP.

As part of our section 7 consultation with the USFS on the LMP, the USFS already consulted on various activities carried out on national forest lands including: Roads and trail management; recreation management; special use permit administration; administrative infrastructure; fire and fuels management; livestock grazing and range management; minerals management; and law enforcement. In our 2005 biological opinion on the LMP, we determined that implementation of the plan was not likely to jeopardize the continued existence of
Acanthomintha ilicifolia
. Since critical habitat has not been previously proposed or designated for this species, it is anticipated that consultation with the USFS regarding the LMP will be reinitiated. However, because the USFS has already consulted with us on potential impacts to the species related to activities outlined in the LMP, the USFS can supplement its analysis for those activities already analyzed in the LMP with the additional analysis required for critical habitat areas. We do not believe that this additional analysis would place an undue burden on the USFS in this case.

Based on the record before us, we elected not to exclude these lands and are designating lands identified on the CNF that meet the definition of critical habitat and are essential to the conservation of
Acanthomintha ilicifolia
. We will continue to consider on a case-by-case basis in future critical habitat rules whether to exclude specific lands from such designation when we determine that the benefits of such exclusion outweigh the benefits of their inclusion.

Comment 14:
One commenter indicated that the critical habitat proposal, if finalized, may adversely affect the Federal Aviation Administration's (FAA's) and San Diego County's ability to continue to operate McClellan-Palomar Airport in a safe and efficient manner because navigational aides (e.g., lights, maintenance road to access navigational aides) are within the area proposed as subunit 1A.

Our Response:
As stated above in our response to comment 11 above, we removed the lands in subunit 1A that do not contain the PCE, including all active agricultural fields, lands containing navigational aides associated with McClellen-Palomar Airport, a dirt maintenance road, and development areas in the City of Carlsbad. We remapped the boundary of subunit 1A, and we have verified that this area meets the definition of critical habitat. Based on currently available information, we believe that we have removed all existing navigational aides from the designated critical habitat. Additionally, we do not believe that regular maintenance of any navigational aides that we are currently unaware of, but have been inadvertently included in the designation, will adversely modify critical habitat. We are committed to working with the FAA and staff of McClellen-Palomar Airport to ensure that the designation of critical habitat does not impact the future safe and efficient operation of the airport.

Summary of Changes From the Proposed Rule

In our March 14, 2007, proposed rule we identified 1,936 acres (ac) (783 hectares (ha)) of essential habitat for
Acanthomintha ilicifolia
in four units and seventeen subunits (72 FR 11946). At that time we proposed to exclude 1,302 ac (527 ha) under section 4(b)(2) of the Act (72 FR 11946; March 14, 2007). As we continued work on the proposed designation, we made two types of changes that affected the total area considered to meet the definition of critical habitat (what we will refer to as “essential habitat”). First, we corrected simple mapping errors; for example, in one case we tallied a single piece of land twice in calculating the total number of acres thought to be essential habitat. Second, we removed areas that did not qualify as essential habitat either because they were developed and degraded or because they did not contain the PCE and were not otherwise considered essential. Table 1 depicts the changes made to the proposed rule published on March 14, 2007, and indicates how much area was removed (or added as was the case for some of the corrections) for each of the two reasons discussed above. As we continued work on the designation, we notified the public of new information we were using to make changes to the critical habitat (72 FR 66122, November 27, 2007; 73 FR 27483, May 13, 2008). However, Table 1 and this discussion focus on the changes from the March 14, 2007, proposed rule (72 FR 11946) to this final rule. The details related to these changes are explained below.

Table 1—Areas Proposed as Critical Habitat (72 FR 11946, March 14, 2007), Area Removed or Added as a Correction, Area Removed as Non-Essential Habitat, and Final Critical Habitat Designation

Critical habitat unit/subunit

Essential
habitat in
the March 14, 2007
proposed rule *

Area
subtracted or
added as a
correction *

Area removed because it was not essential habitat *

Essential
habitat as
of this final rule *

Unit 1: Northern San Diego County:

1A. Palomar Airport
88 ac (36 ha)

26 ac (11 ha)
62 ac (25 ha).

1B. Southeast Carlsbad
73 ac (29 ha)

16 ac (6 ha)
57 ac (23 ha).

1C. Manchester
92 ac (37 ha)

13 ac (5 ha)
79 ac (32 ha).

Unit 2: Central San Diego County:

2A. Los Peñasquitos Canyon
63 ac (25 ha)

63 ac (25 ha).

2B. Sabre Springs
52 ac (22 ha)
Subtracted: 0 ac (1 ha)

52 ac (21 ha).

2C. Sycamore Canyon
306 ac (124 ha)

306 ac (124 ha).

2D. Slaughterhouse Canyon
77 ac (31 ha)

77 ac (31 ha).

Unit 3: Viejas Mountain and Poser Mountain:

3A. Viejas Mountain
33 ac (13 ha)

1 ac (<1 ha)
32 ac (13 ha).

3B. Viejas Mountain
208 ac (84 ha)

15 ac (6 ha)
193 ac (78 ha).

3C. Viejas Mountain
318 ac (128 ha)

42 ac (16 ha)
276 ac (112 ha).

3D. Viejas Mountain
82 ac (33 ha)

82 ac (33 ha).

3E. Poser Mountain
34 ac (14 ha)

34 ac (14 ha).

3F. Poser Mountain
163 ac (66 ha)

8 ac (3 ha)
155 ac (63 ha).

Unit 4: Southern San Diego County:

4A. McGinty Mountain
18 ac (7 ha)
Added: 2 ac (1 ha)

20 ac (8 ha).

4B. McGinty Mountain
220 ac (89 ha)
Subtracted: 72 ac (29 ha)

148 ac (60 ha).

4C. McGinty Mountain
27 ac (11 ha)
Added: 1 ac (0 ha)

28 ac (11 ha).

4D. Hollenbeck Canyon
84 ac (34 ha)

84 ac (34 ha).

Total
1,936 ac (783 ha) **
Subtracted: 69 ac (29 ha)
121 ac (48 ha)
1,748 ac (707 ha).

* The values in this table do not represent an actual conversion of acres to hectares.

** The sum of the values in this column is 1,938 ac (783 ha), whereas the value given for the total in the Table 1 of the March 14, 2007,
Federal Register
notice was 1,936 ac (783 ha). This difference is due to rounding and the conversion of values from acres to hectares on a subunit-by-subunit basis rather than for the critical habitat as a whole.

(1) In the proposed rule (72 FR 11946; March 14, 2007), we proposed to exclude a total of 95 ac (38 ha) of private lands in subunits 3C, 3D, and 3F from the final critical habitat designation under section 4(b)(2) of the Act. We believed these lands were within the planning boundary for the County of San Diego approved subarea plan under the San Diego MSCP. However, the private lands in subunits 3C, 3D, and 3F are not within the planning boundary for the County of San Diego subarea plan under the MSCP; therefore, consideration for exclusion under that HCP was inappropriate. All lands that meet the definition of critical habitat in subunits 3C, 3D, and 3F are now designated as critical habitat.

(2) In the proposed rule (72 FR 11946; March 14, 2007), the maps and boundary descriptions of subunits 4A and 4B were delineated correctly; however, the area estimates were incorrect. The correct area for subunit 4A is 20 ac (8 ha) rather than 18 ac (7 ha), and the correct area for subunit 4B is 148 ac (60 ha) rather than 220 ac (89 ha) (see Table 1). Non-Federal lands in subunits 4A and 4B are excluded from critical habitat, and the federally owned lands in subunit 4A are designated as critical habitat.

(3) In the proposed rule (72 FR 11946; March 14, 2007), we did not identify that subunit 4A contained 2 ac (1 ha) of federally owned land, and subunit 4C contained 1 ac (<1 ha) of federally owned land. Both of these subunits include land in the Service's San Diego National Wildlife Refuge (SDNWR). We proposed to exclude all non-Federal lands in subunits 4A and 4C from the final designation based on the benefits provided to
Acanthomintha ilicifolia
by the County of San Diego subarea plan under the MSCP. While we are excluding all private and non-Federal public lands covered by the subarea plan in this final rule, this exclusion

does not apply to Federal lands; therefore, we are designating 3 ac (1 ha) on the SDNWR in Unit 4.

(4) We re-evaluated the areas proposed as critical habitat based on more up-to-date aerial imagery, field visits, and the most recent version of the HabiTrak database (i.e., a database that shows areas lost to development in the area covered by the MSCP). We determined that some areas proposed as critical habitat no longer contain the PCE. Therefore, we removed these areas from critical habitat. Below we describe the specific areas that we removed from critical habitat:

(a) Subunit 1A, Palomar Airport—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 88 ac (36 ha). After re-evaluating this area, we found that approximately 26 ac (11 ha) do not contain the PCE, including all active agricultural fields, lands containing navigational aides associated with McClellen-Palomar Airport, a dirt maintenance road, and development areas in the City of Carlsbad (see Table 1). As a result, we determined that 62 ac (25 ha) meet the definition of critical habitat in subunit 1A. Of the 62 ac (25 ha), we are designating 60 ac (24 ha) as critical habitat, and we are excluding 2 ac (1 ha) from critical habitat under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section).

(b) Subunit 1B, Southeast Carlsbad—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 73 ac (30 ha). After re-evaluating this area, we found that approximately 16 ac (7 ha) are regularly maintained wildland-urban interface and do not support the PCE for
Acanthomintha ilicifolia
; therefore, we removed these 16 ac (7 ha) from critical habitat (see Table 1). As a result, we determined that 57 ac (23 ha) meet the definition of critical habitat in subunit 1B. We are excluding all of the 57 ac (7 ha) from critical habitat under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section).

(c) Subunit 1C, Manchester—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 92 ac (37 ha). After re-evaluating this area, we found that approximately 13 ac (5 ha) are fragmented by suburban development or are too steep to support the PCE for
Acanthomintha ilicifolia
; therefore, we removed these 13 ac (5 ha) from critical habitat (see Table 1). As a result, we determined that 79 ac (32 ha) meet the definition of critical habitat in subunit 1C. Of the 79 ac (32 ha) that meet the definition of critical habitat, we are designating 9 ac (4 ha) as critical habitat, and we are excluding 70 ac (28 ha) from critical habitat under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section).

(d) Subunit 3A, Viejas Mountain—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 33 ac (13 ha). After re-evaluating this area, we found that approximately 1 ac (<1 ha) is developed and no longer supports the PCE for
Acanthomintha ilicifolia
; therefore, we removed this 1 ac (<1 ha) from critical habitat (see Table 1). As a result, we determined that 32 ac (13 ha) meet the definition of critical habitat in subunit 3A. We are excluding all of the 32 ac (13 ha) from critical habitat under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section).

(e) Subunit 3B, Viejas Mountain—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 208 ac (84 ha). After re-evaluating this area, we found that approximately 15 ac (6 ha) are developed and no longer support the PCE for
Acanthomintha ilicifolia
; therefore, we removed these 15 ac (6 ha) from critical habitat (see Table 1). As a result, we determined that 193 ac (78 ha) meet the definition of critical habitat in subunit 3B. Of the 193 ac (78 ha) that meet the definition of critical habitat in subunit 3B, we are designating 52 ac (21 ha) as critical habitat, and we are excluding 141 ac (57 ha) from critical habitat under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section).

(f) Subunit 3C, Viejas Mountain—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 318 ac (128 ha). After re-evaluating this area, we found that approximately 42 ac (16 ha) are impacted by rural development and do not contain the PCE; therefore, we removed these 42 ac (16 ha) from critical habitat (see Table 1). As a result, we determined that 276 ac (112 ha) meet the definition of critical habitat in subunit 3C. We are designating all of the 276 ac (112 ha), which are federally owned, as critical habitat.

(g) Subunit 3F, Poser Mountain—In the proposed rule (72 FR 11946; March 14, 2007), we indicated that this subunit contained 163 ac (66 ha). After re-evaluating this area, we found that approximately 8 ac (3 ha) are impacted by rural development or agricultural activities and do not contain the PCE; therefore, we removed these 8 ac (3 ha) from critical habitat (see Table 1). As a result, we determined that 155 ac (63 ha) meet the definition of critical habitat in subunit 3F. We are designating the 155 ac (63 ha), all of which are federally owned, as critical habitat.

(5) In the proposed rule (72 FR 11946; March 14, 2007), we proposed the exclusion of lands in subunit 1A and 1B covered by the Carlsbad Habitat Management Plan (HMP) under the MHCP from the designation of critical habitat under section 4(b)(2) of the Act. Upon further analysis of the Carlsbad HMP, we found that coverage of
Acanthomintha ilicifolia
under this HCP is contingent on compliance with the conservation measures outlined in the HMP (i.e., a funded management plan in place) and the completion of the San Marcos subarea plan under the MHCP. We announced that we were reconsidering this exclusion in our May 13, 2008,
Federal Register
notice (73 FR 27483); we did not receive public comments on this subject. However, we did not identify any lands in San Marcos that meet the definition of critical habitat as described in the “Criteria Used to Identify Critical Habitat” section. Therefore, we analyzed the exclusion of subunit 1A and 1B in more detail and concluded that exclusion is appropriate because the essential habitat under the Carlsbad HMP is conserved and has management in place (see “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion). We are designating the remaining 60 ac (24 ha) of land owned by the County of San Diego in subunit 1A because it is not covered by the Carlsbad HMP.

(6) In the proposed rule (72 FR 11946; March 14, 2007), we proposed the exclusion of lands in subunit 1C covered by the pending Encinitas subarea plan under the MHCP from the designation of critical habitat under section 4(b)(2) of the Act. At this time, the Encinitas subarea plan under the MHCP has not been completed. However, the majority of subunit 1C is part of the Manchester Avenue Mitigation Bank and is actively managed for
Acanthomintha ilicifolia
(Spiegelberg 2005, p. 1-33). We determined that the benefits of excluding lands within the conservation bank area from critical habitat designation outweigh the benefits of including the area, and that their exclusion will not result in extinction of this species. Therefore, we are excluding 70 ac (28 ha) of subunit 1C under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion),

and we are designating the remaining 9 ac (4 ha) of private lands outside the Manchester Avenue Mitigation Bank as critical habitat (see “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion).

(7) In the proposed rule (72 FR 11946; March 14, 2007), we proposed the exclusion of non-Federal lands covered by the City of San Diego subarea plan under the MSCP in subunits 2A and 2B and the exclusion of non-Federal lands covered by the County of San Diego subarea plan under the MSCP in subunits 2C, 2D, 3A, 3B, 4A, 4B, 4C, and 4D from the designation of critical habitat under section 4(b)(2) of the Act. In this final rule, we determined that the benefits of exclusion outweigh the benefits of inclusion of these lands and that their exclusion will not result in extinction of this species. Therefore, we excluded all non-Federal lands in subunits 2A and 2B covered by the City of San Diego subarea plan and all non-Federal lands in subunits 2C, 2D, 3A, 3B, 4A, 4B, 4C, and 4D covered by the County of San Diego subarea plan, under section 4(b)(2) of the Act (see “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion). Federally owned lands in subunits 3B, 4A, and 4C are designated as critical habitat.

(8) In our March 14, 2007, proposed rule (72 FR 11946), we indicated that all subunits except 3E and 4D were known to be occupied by the species at the time of listing (October 13, 1998). We now consider subunits 3E and 4D to have been occupied at the time of listing. Even though these occurrences were not discovered until after the species was listed in 1998, over 1,000 plants were recorded at each of these sites when they were first discovered in 2000 and 2001, respectively. We believe the large population size indicates that the occurrences were established for several years prior to their discovery and were established at the time the species was listed.
Acanthomintha ilicifolia
seeds do not disperse in large numbers and any new population of
A. ilicifolia
would likely start out small and take several years to reach a population size greater than 1,000 plants. Therefore, since these large populations were discovered 2 to 3 years after listing, we consider all subunits proposed or designated as critical habitat to have been occupied at the time of listing (see “Criteria Used To Identify Critical Habitat” section). We designated critical habitat in subunit 3E, and we excluded subunit 4D as discussed above.

(9) We made two corrections to our description of the PCE. First, in the proposed rule (72 FR 11946; March 14, 2007), we omitted grassland vegetation as one of the vegetation types in which
Acanthomintha ilicifolia
is commonly found. This information was discussed in the proposed rule, but was inadvertently left out of the PCE. We included it in the PCE in this final rule. Second, in the proposed rule (72 FR 11946; March 14, 2007), we indicated that deep fissures in the clay soils associated with
A. ilicifolia
are approximately 2 feet (60 cm) deep. However, there are only observational discussions and no formal studies on this topic. We broadened the statement on this habitat feature in the PCE to state that the fissures in the soil range in depth from approximately 1 to 2 feet (30 to 60 cm).

As a result of the removals and corrections outlined above, a total of approximately 1,748 ac (707 ha) meets the definition of critical habitat and is considered essential habitat for
Acanthomintha ilicifolia
. We are excluding approximately 1,077 ac (435 ha) of essential habitat under section 4(b)(2) of the Act because we determined that the benefits of excluding those lands from the critical habitat designation outweigh the benefits of including them in the designation (see “Exclusions Under Section 4(b)(2) of the Act” section) . In conclusion, we are designating 671 ac (272 ha) of land in San Diego County as critical habitat for
A. ilicifolia
in this final rule.

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

(a) Essential to the conservation of the species and

(b) Which may require special management considerations or protection; and

(ii) Specific areas outside the geographical area occupied by a species at the time it is listed, upon a determination that such areas are essential for the conservation of the species.

Conservation, as defined under section 3 of the Act, means the use of all methods and procedures that are necessary to bring any endangered or threatened species to the point at which the measures provided under 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, or transplantation.

Critical habitat receives protection under section 7 of the Act through the prohibition against Federal agencies carrying out, funding, or authorizing the destruction or adverse modification of critical habitat. Section 7(a)(2) of the Act requires consultation on Federal actions that may affect critical habitat. The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other conservation area. Such designation does not allow the government or public to access private lands. Such designation does not require implementation of restoration, recovery, or enhancement measures by private landowners. Where a landowner requests Federal agency funding or authorization for an action that may affect a listed species or critical habitat, the consultation requirements of section 7(a)(2) would apply, but even in the event of a destruction or adverse modification finding, the landowner's obligation is not to restore or recover the species, but to implement reasonable and prudent alternatives to avoid destruction or adverse modification of critical habitat.

For inclusion in a critical habitat designation, habitat within the geographical area occupied by the species at the time it was listed must contain the physical or biological 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 those physical and biological features laid out in the appropriate quantity and spatial arrangement for the conservation of the species).

Occupied habitat that contains the features essential to the conservation of the species meets the definition of critical habitat only if those features may require special management considerations or protection.

Under the Act, we can designate unoccupied areas as critical habitat only when we determine that the best available scientific data demonstrate that the designation of that area is essential for the conservation of the species.

Section 4 of the Act requires that we designate critical habitat on the basis of the best scientific and commercial data available. Further, our Policy on Information Standards Under the

Endangered Species Act (published in the
Federal Register
on July 1, 1994 (59 FR 34271)), the Information Quality Act (section 515 of the Treasury and General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), and our associated Information Quality Guidelines provide criteria, establish procedures, and provide guidance to ensure that our decisions are based on the best scientific data available. They require our biologists, to the extent consistent with the Act and with the use of the best scientific data available, to use primary and original sources of information as the basis for recommendations to designate critical habitat.

When we are determining which areas should be designated as critical habitat, our primary source of information is generally the information developed during the listing process for the species. Additional information sources may include the recovery plan for the species, articles in peer-reviewed journals, conservation plans developed by States and counties, scientific status surveys and studies, biological assessments, or other unpublished materials and expert opinion or personal knowledge. In the case of
Acanthomintha ilicifolia
, several botanists and land managers conducted field assessments and management experiments that were helpful in identifying the areas that meet the definition of critical habitat. There is no recovery plan for
A. ilicifolia
.

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 we may eventually determine, based on scientific data not now available to the Service, are necessary for the recovery of the species. For these reasons, a critical habitat designation does not signal that habitat outside the designated area is unimportant or may not be required for recovery of the species.

Areas that support populations, but are outside the critical habitat designations, will continue to be subject to conservation actions we implement under section 7 of the Act. They are also subject to the regulatory protections afforded by the section 7(a)(2) jeopardy standard, as determined on the basis of the best available scientific information at the time of the Federal agency action. Federally funded or permitted projects affecting listed species outside their designated critical habitat areas may still result in jeopardy findings in some cases. Similarly, critical habitat designations made on the basis of the best available information at the time of designation will not control the direction and substance of future recovery plans, habitat conservation plans (HCPs), or other species conservation planning efforts if information available at the time of these planning efforts calls for a different outcome.

Primary Constituent Elements

In accordance with section 3(5)(A)(i) of the Act and the regulations at 50 CFR 424.12, in determining which areas occupied by the species at the time of listing to designate as critical habitat, we consider the physical and biological features essential to the conservation of the species that may require special management considerations or protection to be the PCEs laid out in the appropriate quantity and spatial arrangement for the conservation of the species. These physical and biological features include, but are not limited to:

(1) Space for individual and population growth and for normal behavior;

(2) Food, water, air, light, minerals, or other nutritional or physiological requirements;

(3) Cover or shelter;

(4) Sites for breeding, reproduction, or rearing (or development) of offspring; and

(5) Habitats that are protected from disturbance or are representative of the historic, geographical, and ecological distributions of a species.

We derived the specific primary constituent element required for
Acanthomintha ilicifolia
from its biological needs, as described in the proposed critical habitat rule published in the
Federal Register
on March 14, 2007 (72 FR 11946), and below.

Space for Individual and Population Growth and Normal Behavior

Acanthomintha ilicifolia
occurs on isolated patches of clay soils derived from gabbro and soft calcareous sandstone substrates (Oberbauer and Vanderwier 1991, pp. 208-209). The soils derived from gabbro substrates are red to dark brown clay soils, and those derived from soft calcareous sandstone are gray clay soils. These patches of clay soils are called “clay lenses.” In San Diego County, California, and northern Baja California, Mexico, clay lenses are known to support a variety of narrow endemic (restricted to a specific geographic area) plants. Clay lenses tend to have an open or unpopulated look because many common species cannot tolerate living on these clay soils. Clay lenses are typically devoid of woody, perennial shrubs (Oberbauer and Vanderwier 1991, pp. 208-209) (PCE). Shrubs have difficulty surviving on these soils because in the rainy winter months these soils become saturated with water and the large root systems of shrubs are not able to get oxygen (Oberbauer and Vanderwier 1991, pp. 208-209). Another reason it is difficult for shrubs to take root and become established on the clay soil is because as the soils become saturated with water they expand and when the soils dry they contract and crack. The harsh conditions that clay soils exhibit make clay lenses a difficult microhabitat for annual native plants to grow on, which limits the number and density of common native plants on clay lenses. Due to the absence of most common native vegetation from clay lenses, the areas where
A. ilicifolia
occurs appear as open areas surrounded by areas populated by denser vegetation.

In addition to the characteristics discussed above, the texture and structure of the clay lenses are essential for supporting the seedling establishment and growth of
Acanthomintha ilicifolia
. This soil provides many small pockets and deeper fissures where seeds from
A. ilicifolia
become lodged as they fall from decomposing plants (Bauder and Sakrison 1999, p. 28). The seeds stay in the soils until the temperatures become cooler in the winter months and the soil becomes saturated with the winter rains (Bauder and Sakrison 1997, p. 28-29). The seedlings then germinate and grow to mature plants. These plants do best when they are not crowded or shaded by other plants (Bauder and Sakrison 1999, p. 12). The loose, crumbly texture of the soil provides the proper substrate to hold the seed bank and allow for root growth.

Clay lenses are generally inhabited by a specific flora that consists of forbs, native grasses, and geophytes (perennial plants propagated by buds on underground bulbs, tubers, or corms, such as lilies, iris, and onions) (Oberbauer and Vanderwier 1991, pp. 208-209), which are better adapted to the harsh conditions mentioned above. Native plant species that characterize the vegetation found with
Acanthomintha ilicifolia
on clay lenses include
Hesperevax sparsiflora
var.
sparsiflora
(erect evax),
Harpagonella palmeri
(Palmer's grappling-hook),
Convolvulus simulans
(bindweed),
Apiastrum angustifolium
(mock parsley), and
Microseris douglasii
ssp.
platycarpha
(small flowered microseris) (Bauder
et al.
1994, pp. 9-10; McMillan 2006, p. 1; Vinje 2006b, pp. 1-2).

Clay lenses generally form on gentle slopes. An analysis of 20 sites where

Acanthomintha ilicifolia
was observed found that the slopes range from 0 to 25 degrees, with the majority of the sites having slopes below 20 degrees (Bauder
et al.
1994, pp. 10-11). This study found that many thriving, natural populations were on slopes that faced southeast, south, southwest, and west (Bauder
et al.
1994, pp. 10-11). Using GIS, we found that the known populations of
A. ilicifolia
range in elevation from sea level to 3,000 ft (914 m).
Acanthomintha ilicifolia
occurs on soils mapped as Las Posas, Olivenhain, Redding, Huerhuero, Altamont, Cieneba, and Linne (Service GIS database; soils described by Bowman 1973, pp. 22-24, 38-40, 54-55, 61-64, 67-68, and 71-72).

Water and Hydrology

The loose, crumbly clay soils that support
Acanthomintha ilicifolia
act like a sponge and are saturated by winter rains. The saturation of these soils allows for seeds of
A. ilicifolia
to imbibe with water and germinate in the cool winter months of the Mediterranean-type climate (Bauder and Sakrison, 1997, p. 32). As such, the species requires a natural hydrological regime to reproduce. However, we do not have specific information on the hydrological regime that this species requires, other than the general characteristics of a Mediterranean-type climate; therefore, we did not include hydrological regime as a primary constituent element.

Reproduction and Pollination

The breeding system of
Acanthomintha ilicifolia
has not been studied, but it has been determined that other members of the genus
Acanthomintha
are self-compatible (Steeck 1995, pp. 27-33). A 1996 study (Bauder and Sakrison 1997, p. 38) found that several insect species visited the flowers and moved from plant to plant. These insects represented possible pollinators of
A. ilicifolia
; however, none were thought to represent species-specific pollinators (Bauder and Sakrison 1997, p. 39). Since we do not have information on any species-specific pollinators that visit
A. ilicifolia
, we did not include pollinators as a primary constituent element.

Primary Constituent Element for Acanthomintha ilicifolia

Within the geographical area known to be occupied by
Acanthomintha ilicifolia, at the time of listiing we must identify the physical and biological features that may require
special management considerations or protection.

In this case, we identified one PCE with multiple parts. All areas designated as critical habitat for
Acanthomintha ilicifolia
are occupied, occur within the species' historic geographic range, and contain the PCE required to support at least one life history function. The data provided in the PCE is summarized from existing scientific data. It is important to note that the variable amounts and timing of precipitation in southern California do not result in favorable conditions for
A. ilicifolia
in every year.

Based on the above needs and 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 determined that the PCE for
Acanthomintha ilicifolia
is:

Clay lenses that provide substrate for seedling establishment and space for growth and development of
Acanthomintha ilicifolia
that are:

(a) Within chaparral, grassland, and coastal sage scrub;

(b) On gentle slopes ranging from 0 to 25 degrees;

(c) Derived from gabbro and soft calcareous sandstone substrates with a loose, crumbly structure and deep fissures approximately 1 to 2 feet (30 to 60 cm); and

(d) Characterized by a low density of forbs and geophytes, and a low density or absence of shrubs.

This designation encompasses those areas containing the PCE necessary to support one or more of the species' life history functions laid out in the appropriate quantity and spatial arrangement for the conservation of the species. All units and subunits in this designation contain the PCE and support multiple life processes. As stated in the “Criteria Used To Identify Critical Habitat” section of this rule, we believe that we can conserve
Acanthomintha ilicifolia
through the designation of critical habitat within its extant range and are not including any areas outside of the geographical area occupied by the species.

Special Management Considerations or Protection

When designating critical habitat, we assess whether the occupied areas contain features that are essential to the conservation of the species and that may require special management considerations or protection.

As stated in the final listing rule, threats to
Acanthomintha ilicifolia
include trampling and grazing, the presence of exotic plant species, off-road vehicles (ORVs), mining, and urbanization (63 FR 54938). Through our review of the existing data on
A. ilicifolia
, we conclude that the threats listed in the final listing rule continue to impact this species and its essential physical and biological features.

Urban development near
Acanthomintha ilicifolia
populations may alter the habitat characteristics required by this species. The destruction of habitat can change the slope and aspect of a site, making it uninhabitable for
A. ilicifolia
(PCE 1(b)). The close proximity of development to populations of
A. ilicifolia
may affect other aspects of the site. For example, increased water runoff from developments may erode the clay lense and change the topography of the site (Bauder
et al.
1994, p. 23) (PCE 1(b and c)).

The introduction of exotic plant species such as
Centaurea melitensis
can drastically change the species present in (PCE 1(a)), and eliminate the open character of, the clay lense habitat (PCE 1(d)).
Centaurea melitensis
has been shown, in field and greenhouse experiments, to negatively effect the biomass (growth) and seed production (reproduction) of
Acanthomintha ilicifolia
(Bauder and Sakrison 1999, p. 16). Populations of
A. ilicifolia
that are close to urbanized areas or in areas that are heavily grazed generally have a high density of exotic plant species (PCE 1(a)). In disturbed soils,
C. melitensis
is a common weed. When this and other exotic plant species become established, they can out-compete
A. ilicifolia
for light, water, nutrients, and space.
Acanthomintha ilicifolia
often grows larger and at a higher density when competition with exotic weeds is reduced (Bauder and Sakrison 1999, pp. 12-16; Vinje 2007, p. 10).

The final listing rule (63 FR 54938) discusses the impacts of ORV activity and trampling. In recent years, the impacts associated with the use of mountain bikes have been documented to cause similar impacts (Vinje 2006a, p. 1). Trampling, ORV activity, and mountain bike use in
Acanthomintha ilicifolia
habitat can compact the loose, crumbly soils (PCE 1(c)). Repeated travel over a trail or track degrades the habitat of
A. ilicifolia
in two ways: (1) By displacing soil; and (2) by compacting soil. These activities, in turn, can destroy individual plants and can reduce the amount of water that can percolate into the soil, thus reducing the plant's ability to grow and reproduce.

Mining is documented as a threat at two sites known to support
Acanthomintha ilicifolia
(63 FR 54938; Bauder
et al.
1994, p. 17). Mining can alter many aspects of
A. ilicifolia

habitat. Heavy machinery can compact or remove clay lenses (PCE 1(c)) or alter the slope of an area (PCE 1(b)). The grading of large areas adjacent to
A. ilicifolia
habitat can make those areas vulnerable to invasion by exotic plant species and lead to the subsequent crowding and shading of
A. ilicifolia
habitat (PCE 1(d)). These impacts may in turn lead to the disruption of the growth and reproduction of
A. ilicifolia
.

The protection of habitat for
Acanthomintha ilicifolia
from development is the first measure of protection needed for populations of this species (PCE 1(a)). The control of exotic plant species, the maintenance and enhancement of clay lense habitat, the control of incompatible and often illegal activities such as off-road vehicle use and other unauthorized recreational impacts, and careful oversight of adjacent activities such as mining, will help to ensure the long-term conservation for
A. ilicifolia
and the physical and biological features essential for the conservation of the species.

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 the specific occupied areas that contain the features essential to the conservation of species which may require special management considerations or protection, as well as when determining if any specific areas outside the geographical area occupied by the species are essential to the conservation of the species. We only designate areas outside the geographical area occupied by a species when a designation limited to its present range would be inadequate to ensure the conservation of the species (50 CFR 424.12(e)).

Species and plant communities that are protected across their ranges are expected to have lower likelihoods of extinction (Soule and Simberloff 1986; Scott
et al.
2001, pp. 1297-1300); therefore, essential habitat should include multiple locations across the entire range of the species to prevent range collapse and contribute to recovery of the species. Conserving habitat variability throughout the range of this species is important to capture the range of habitat diversity and, potentially, genetic variability, the preservation of which is likely to ensure the conservation of those
Acanthomintha ilicifolia
occurrences that are most likely to persist under future environmental conditions and to contribute to species recovery. Genetic variation generally results from the effects of population isolation and adaptation to locally distinct environments (Lesica and Allendorf 1995, pp. 754-757; Fraser 2000, pp. 49-51; Hamrick and Godt 1996, pp. 291-295). We sought to include the range of ecological conditions in which
A. ilicifolia
is found to preserve the genetic variation that may result from adaptation to local environmental conditions, as documented in other plant species (e.g., see Hamrick and Godt 1996, pp. 299-301; Millar and Libby 1991, pp. 150, 152-155). Locations that possess unique ecological characteristics are those that represent the full range of environmental variability where
A. ilicifolia
has evolved, and therefore, are likely to promote the adaptation of the species to different environmental conditions and contribute to species recovery.

All critical habitat subunits discussed in this designation are occupied by the species. Occupied areas were determined from survey data and element occurrence data in the California Natural Diversity Database (CNDDB) (CNDDB 2006). For the purpose of this designation, we assumed that each element occurrence represents a population of
Acanthomintha ilicifolia
, except in cases where there are several element occurrences located within 1 mile (1.6 km) of each other and the habitat is not fragmented by manmade features. In these cases, we considered the group of element occurrences as a single population. Examples of this include the Manchester Avenue Mitigation Bank in Encinitas (element occurrence (EO) 28, EO 42, and EO 54), McGinty Mountain near Jamul (EO 21, EO 22, and EO 30), and Viejas and Poser Mountains near Alpine (EO 12, EO 50, EO 51, EO 62, EO 73, EO 74, and EO 75).

Using GIS data in the areas identified as occupied by this species as a guide, we identified the areas that contained the physical and biological features essential to the conservation of
Acanthomintha ilicifolia
(the PCE). To map the areas that meet the definition of critical habitat, we identified areas that contain the PCE in the quantity and spatial distribution essential for the conservation of this species using the following criteria: (1) Support populations that occur on rare or unique habitat within the species' range; (2) support the largest known populations of
A. ilicifolia;
or (3) support the most stable populations of
A. ilicifolia
. These criteria are explained in greater detail below. Areas containing the PCE and that meet at least one of the above criteria were considered to meet the definition of critical habitat. We included adjacent areas up to 500 ft (128 m) that contained habitat for
A. ilicifolia
to capture the full extent of each population including the seed bank, as this species fluctuates annually in population density and spatial distribution. Data from past survey efforts and recent field work conducted by Service biologists frequently found occurrences of
A. ilicifolia
located outside the exact areas where this species was mapped (Bauder et al. 1994, pp. 14-15; CNDDB 2006, pp. 11, 28-29, and 70; Service unpublished data 2006).

The resulting areas meet the definition of critical habitat. To evaluate locations occupied by this species we used the CNDDB (CNDDB 2006, pp. 1-74), a survey of
A. ilicifolia
habitat and populations by Bauder
et al.
(1994, pp. 7-23), biological surveys (City of San Diego 2000, pp 2-6; City of San Diego 2001, pp. 1-10; City of San Diego 2003, pp. 1-11; City of San Diego 2004, pp. 1-7; City of San Diego 2005, pp. 1-5; Conservation Biology Institute 2002, p. A3-1; County of San Diego 2002, p. 17; Dudek and Associates, Inc. 2006, Appendix A, pp. 3-4; Helix Environmental Planning, Inc. 2002, p. 6; REC Consultants, Inc. 2004, figure 5), and interviews with botanists working on this species (Kelley 2005, p. 1; McMillan 2006, p. 1; Vinje 2006b, pp. 1-2).

The first criterion we used to identify critical habitat is any area that supports a population in rare or unique habitat within the species' range. The majority of areas that currently support
Acanthomintha ilicifolia
are on dark brown to reddish brown clay soils derived from gabbro substrates. Historically,
A. ilicifolia
also occurred on gray clay soils that are derived from soft calcareous sandstone substrates. Conserving unique habitats for
A. ilicifolia
may help to reduce the risk of extinction for this species as it may capture remaining ecological diversity within the range of the species and contribute to the recovery of this species. This ecological diversity may be reflected in genetic diversity; however, at this time, no one has investigated the genetic structure of this species. The only remaining population on the calcareous clay soil type is northeast of the intersection of Palomar Airport Road and El Camino Real, in the City of Carlsbad.

The second criterion we used to identify critical habitat is any area that supports one of the largest known populations of
Acanthomintha ilicifolia
. The CNDDB includes data for this species that date back to 1978. Populations of this species range from

just a few individuals to several thousand plants. The majority of the known populations range from 50 to 2,000 plants. Yet, there are four populations that stand out as the largest, each having greater than 25,000 plants. These large populations are vital for the conservation of this species and occur within large blocks of open space that are less likely to be impacted by edge effects associated with the smaller populations in highly urbanized areas. Therefore, the conservation of these large populations will increase the persistence of the species across its range and the overall recovery of this species. The four largest populations and the estimated population at each location are: Sycamore Canyon, 31,000 plants; Slaughterhouse Canyon, 60,000 plants; Viejas and Poser Mountains, 29,650 plants; and Hollenbeck Canyon, 100,000 plants. These four populations represent approximately 75 percent of the total known plants of this species.

The third criterion we used to identify critical habitat is any area that supports one of the most stable populations of
Acanthomintha ilicifolia
. For the purpose of this critical habitat designation, we defined the most stable populations as those that contained more than 1,000 plants at least once during the period for which we have survey data. We evaluated the population data from the CNDDB and determined that populations with more than 1,000 plants at some time had the ability to rebound following years with low population numbers. Therefore, we considered populations with more than 1,000 plants to have a high probability of persisting into the future and contributing to the conservation of the species. Although these areas are not free from exotic plant competitors, these populations have persisted over time without being out-competed by the exotic plant species present. This may partially be a result of the low density of exotic plant species at these locations and, in some cases, the management of exotic plant species. All of the areas that meet criterion two also meet criterion three. Five additional areas have populations of
A. ilicifolia
that meet criterion three: the southeast portion of the City of Carlsbad; the Manchester Avenue Mitigation Bank; Los Peñasquitos Canyon; Sabre Springs; and McGinty Mountain. These areas support the most stable populations of
A. ilicifolia
.

All 10 areas that we identified as meeting the criteria for critical habitat contain the PCE essential for the conservation of this species. These areas support the only population on calcareous clay soil, the largest populations, and the most stable populations of
Acanthomintha ilicifolia
. Application of these criteria captures the physical and biological features essential to the conservation of the species in the appropriate quantity and spatial arrangement and represents the range of environmental variability for this species. Although a genetic analysis of
A. ilicifolia
is not available, these criteria likely capture the full breadth of important habitat types and are expected to protect the genetic variability of this species. The identified habitat areas, if managed for threats to the physical and biological features, are adequate to ensure the conservation of
A. ilicifolia
.

When determining the critical habitat boundaries for this final rule, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because such lands lack the PCE for
Acanthomintha ilicifolia
. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed lands. Any such structures and the land under them inadvertently left inside critical habitat boundaries shown on the maps of this critical habitat rule have been excluded by text in this final rule. Therefore, a Federal action involving these lands would not trigger section 7 consultation with respect to critical habitat and the requirement of no adverse modification unless the specific action may affect adjacent critical habitat.

Final Critical Habitat Designation

We are designating approximately 671 ac (272 ha) of critical habitat for
Acanthomintha ilicifolia
in three of the four units proposed as critical habitat with a total of 10 subunits. Table 2 outlines the areas that meet the definition of critical habitat, the areas excluded from this final critical habitat, and the area designated as critical habitat. Table 2 also shows a breakdown of the critical habitat based on the ownership of these areas. The critical habitat areas we describe below constitute our current best assessment of areas designated as critical habitat for
A. ilicifolia
. In this section, we did not discuss the details of the areas that are excluded from critical habitat under section 4(b)(2) of the Act. For more information on the areas that are excluded, please see the “Exclusions Under Section 4(b)(2) of the Act” section.

Table 2—Areas That Meet the Definition of Critical Habitat for Acanthomintha ilicifolia, Areas Excluded From This Final Critical Habitat, and Areas Designated as Critical Habitat; Including the Ownership of Each Area

Critical habitat unit
Land ownership
Area that meets the definition of critical habitat
Area excluded from final critical habitat
Area designated as critical habitat

Unit 1: Northern San Diego County:

1A. Palomar Airport
Private
2 ac (1 ha)
2 ac (1 ha)
0 ac (0 ha).

State/Local
60 ac (24 ha)
0 ac (0 ha)
60 ac (24 ha).

1B. Southeast Carlsbad
Private
57 ac (23 ha)
57 ac (23 ha)
0 ac (0 ha).

1C. Manchester
Private
79 ac (32 ha)
70 ac (28 ha)
9 ac (4 ha).

Unit 2: Central San Diego County:

2A. Los Peñasquitos Canyon
State/Local
63 ac (25 ha)
63 ac (25 ha)
0 ac (0 ha).

2B. Sabre Springs
Private
1 ac (<1 ha)
1 ac (<1 ha)
0 ac (0 ha).

State/Local
51 ac (21 ha)
51 ac (21 ha)
0 ac (0 ha).

2C. Sycamore Canyon
Private
30 ac (12 ha)
30 ac (12 ha)
0 ac (0 ha).

State/Local
276 ac (112 ha)
276 ac (112 ha)
0 ac (0 ha).

2D. Slaughterhouse Canyon
Private
77 ac (31 ha)
77 ac (31 ha)
0 ac (0 ha).

Unit 3: Viejas Mountain and Poser Mountain:

3A. Viejas Mountain
Private
32 ac (13 ha)
32 ac (13 ha)
0 ac (0 ha).

3B. Viejas Mountain
Private
141 ac (57 ha)
141 ac (57 ha)
0 ac (0 ha).

Federal
52 ac (21 ha)
0 ac (0 ha)
52 ac (21 ha).

3C. Viejas Mountain
Federal
276 ac (112 ha)
0 ac (0 ha)
276 ac (112 ha).

3D. Viejas Mountain
Private
50 ac (20 ha)
0 ac (0 ha)
50 ac (20 ha).

Federal
32 ac (13 ha)
0 ac (0 ha)
32 ac (13 ha).

3E. Poser Mountain
Federal
34 ac (14 ha)
0 ac (0 ha)
34 ac (14 ha).

3F. Poser Mountain
Federal
155 ac (63 ha)
0 ac (0 ha)
155 ac (63 ha).

Unit 4: Southern San Diego County:

4A. McGinty Mountain
Private
18 ac (7 ha)
18 ac (7 ha)
0 ac (0 ha).

Federal
2 ac (1 ha)
0 ac (0 ha)
2 ac (1 ha).

4B. McGinty Mountain
Private
141 ac (57 ha)
141 ac (57 ha)
0 ac (0 ha).

State/Local
7 ac (3 ha)
7 ac (3 ha)
0 ac (0 ha).

4C. McGinty Mountain
Private
27 ac (11 ha)
27 ac (11 ha)
0 ac (0 ha).

Federal
1 ac (<1 ha)
0 ac (0 ha)
1 ac (<1 ha).

4D. Hollenbeck Canyon
Private
23 ac (9 ha)
23 ac (9 ha)
0 ac (0 ha).

State Local
61 ac (25 ha)
61 ac (25 ha)
0 ac (0 ha).

Total

1,748 ac (707 ha) *
1,077 ac (435 ha) *
671 ac (272 ha) *.

* Values in this table may not sum due to rounding and the conversion of values from acres to hectares.

Unit Descriptions

Unit 1: Northern San Diego County

Unit 1 is located in northern San Diego County, California. The area was occupied at the time of listing, is currently occupied, and contains the features essential to the conservation of
Acanthomintha ilicifolia
that may require special management considerations or protection for
A. ilicifolia
. The habitat in Unit 1 is gently sloping and occurs in the north coastal portion of San Diego County. The habitat included in this unit provides for the conservation of populations of this species that are at the lowest elevations where this species is found. These areas represent coastal terrace terrain and, therefore, are edaphically and ecologically distinct from the other units of critical habitat (subunit 1A) (see “Criteria Used to Identify Critical Habitat” section criterion 1). This unit contains some of the most stable populations of
A. ilicifolia
(subunits 1B and 1C) (see “Criteria Used to Identify Critical Habitat” section criterion 3). Below, we present a brief description of subunits designated as critical habitat in this unit.

Subunit 1A, Palomar Airport

Subunit 1A is located in Carlsbad, California, northeast of the intersection of Palomar Airport Road and El Camino Real. Subunit 1A consists of 60 ac (24 ha) of land owned by the County of San Diego. Subunit 1A meets our selection criteria because it supports a population on a unique soil type (see “Criteria Used to Identify Critical Habitat” section criterion 1). This is the only area where
A. ilicifolia
is still known to occupy calcareous clay soils. The features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from exotic plant species and unauthorized recreational activities.

A portion of the land that meets the definition of critical habitat in this area (2 ac (1 ha)) is covered by the Carlsbad HMP of the San Diego MHCP. We excluded the portion of critical habitat covered by the Carlsbad HMP from critical habitat because we determined the benefits of excluding these lands outweigh the benefits of including these lands in a critical habitat designation. Furthermore, exclusion of these lands will not result in the extinction of this species (see Table 3 and “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion).

Subunit 1B, Southeast Carlsbad

Subunit 1B is located in Carlsbad, California, east of Calle Acervo and west of Paseo Esmerado. All lands within this subunit (57 ac (23 ha)) are covered by the Carlsbad HMP of the San Diego MHCP. We excluded the lands covered by the Carlsbad HMP under the MHCP in this subunit because we determined that the benefits of excluding these lands outweigh the benefits of including these lands in a critical habitat designation. Furthermore, exclusion of these lands will not result in the extinction of this species (see Table 3 and “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion).

Subunit 1C, Manchester

Subunit 1C is located in Encinitas, California, northeast of the intersection of Manchester Avenue and South El Camino Real. Subunit 1C consists of 9 ac (4 ha) of private land. Subunit 1C meets our selection criteria because it supports one of the most stable populations of
Acanthomintha ilicifolia
(criterion 3). The features essential to the conservation of the species in this subunit may require special management considerations or protection to address threats from exotic plant species and unauthorized recreational activities.

The majority of the land that meets the definition of critical habitat in this area (70 ac (28 ha)) is in the Manchester Avenue Mitigation Bank. The Manchester Avenue Mitigation Bank is owned and managed by the Center for Natural Lands Management (CNLM). There is long-term management in place on this site to conserve several sensitive species, including
Acanthomintha ilicifolia
(Spiegelberg 2005, p. 1). We excluded the portion of critical habitat covered by the Manchester Habitat Conservation Area Management Plan (Spiegelberg 2005) from critical habitat because we determined that the benefits of excluding these lands outweigh the benefits of including these lands in a critical habitat designation; exclusion of these lands will not result in the extinction of this species (see Table 3 and “Exclusions Under Section 4(b)(2)

of the Act” section of this final rule for a detailed discussion of this exclusion).

Unit 2: Central San Diego County

Unit 2 is located in an east-west line starting in the County of San Diego on private land east of the Sycamore Canyon/Goodan Ranch Preserve (subunit 2D), occurring on County-owned open space in the Sycamore Canyon/Goodan Ranch Preserve (subunit 2C), occurring on City of San Diego-owned land in Los Peñasquitos Canyon near the border or the City of San Diego and the City of Poway (subunit 2B), and occurring in Peñasquitos Canyon Preserve (subunit 2A). The unit was occupied at the time of listing, is currently occupied, and contains the features essential to the conservation of
Acanthomintha ilicifolia
that may require special management considerations or protection for
A. ilicifolia
. This unit contains some of the largest populations of
A. ilicifolia
(subunits 2C and 2D) (criterion 2) and some of the most stable populations of
A. ilicifolia
(subunits 2A and 2B) (criterion 3). All lands that meet the definition of critical habitat in Unit 2 are covered by either the City of San Diego subarea plan (subunits 2A and 2B) or the County of San Diego subarea plan (subunits 2C and 2D) under the San Diego MSCP and are excluded from the designation. We determined that the benefits of excluding these lands outweigh the benefits of including these lands in the designation and that exclusion of these lands will not result in the extinction of this species (see Table 3 and “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion).

Unit 3: Viejas Mountain and Poser Mountain

Unit 3 is located in San Diego County, California, on Viejas Mountain and Poser Mountain. The area was occupied at the time of listing, is currently occupied, and contains the features essential to the conservation of
Acanthomintha ilicifolia
that may require special management considerations or protection for
A. ilicifolia
. Unit 3 is divided into six subunits, five of which are designated as critical habitat. Due to the proximity of the occurrences in this area and the fact that the habitat is not fragmented by any manmade barriers, we consider these occurrences to be a single population of
A. ilicifolia
. Unit 3 is designated as critical habitat because it supports one of the largest recorded populations of the species (criterion 2). This population is estimated to have greater than 25,000 plants based on the maximum number of plants observed at the different CNDDB element occurrences (EO 12, 6,650 plants in 1991 (subunit 3F); EO 50, 5,600 plants in 1994 (subunit 3B); EO 51, 8,300 plants in 2003 (subunit 3C); EO 62, 1,115 plants in 2000 (subunit 3C); EO 73, 8,750 plants in 1997; and EO 74, 2,000 plants in 2000 (subunit 3E)). The habitat in unit 3 is more mountainous than the other units and provides for the conservation of this species at the highest elevations where this species is found. Therefore, this unit is ecologically distinct from the other units of critical habitat and provides for the largest population of
A. ilicifolia
as measured by the area occupied by the species. Below, we present a brief description of subunits designated as critical habitat in this unit.

Subunit 3A, Viejas Mountain

Subunit 3A is located east of Peutz Valley Road on the western flank of Viejas Mountain. All lands that meet the definition of critical habitat in this area (32 ac (13 ha)) are covered by the County of San Diego subarea plan of the San Diego MSCP. We excluded the lands covered by the County of San Diego subarea plan in this subunit because we determined that the benefits of excluding these lands outweigh the benefits of including these lands in a critical habitat designation. Furthermore, exclusion of these lands will not result in the extinction of this species (see Table 3 and “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion).

Subunit 3B, Viejas Mountain

Subunit 3B is located east of Alpine, California, and north of Interstate 8 on the western slope Viejas Mountain. Subunit 3B consists of 52 ac (21 ha) of land in the Cleveland National Forest (CNF) owned by the U.S. Forest Service (USFS). This subunit was occupied by the species at the time of listing and is currently occupied. Subunit 3B meets our selection criteria because this subunit is part of one of the largest recorded populations of
Acanthomintha ilicifolia
(criterion 2). The features essential to the conservation of the species in this subunit may require special management considerations or protection to address the threat from exotic plant species and recreational activities.

The privately owned lands that meet the definition of critical habitat in this area (141 ac (57 ha)) are covered by the County of San Diego subarea plan of the San Diego MSCP. We excluded the lands covered by the County of San Diego subarea plan in this subunit because we determined that the benefits of excluding these lands outweigh the benefits of including these lands in a critical habitat designation and that exclusion of these lands will not result in the extinction of this species (see Table 3 and “Exclusions Under Section 4(b)(2) of the Act” section of this final rule for a detailed discussion of this exclusion).

Subunit 3C, Viejas Mountain

Subunit 3C is located east of Alpine, California, and north of Interstate 8 on southern slope of Viejas Mountain. Subunit 3C consists of 276 ac (112 ha) of land in the CNF owned by the USFS. This subunit was occupied by the species at the time of listing and is currently occupied. Subunit 3C meets our selection criteria because this subunit is part of one of the largest recorded populations of
Acanthomintha ilicifolia
(criterion 2). The features essential to the conservation of the species in this subu

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3AE8-19194. Public record. Not legal advice.