Federal Register: Part V [50 CFR Part 17]

DEPARTMENT OF THE INTERIOR

CFR Citation: 50 CFR Part 17

RIN ID: RIN 1018-AI77

NOTICE: Part V

DOCUMENT ACTION: Final rule.

SUBJECT CATEGORY: Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Astragalus magdalenae var. peirsonii (Peirson's milk-vetch)

DATES: This rule becomes effective on September 3, 2004.

DOCUMENT SUMMARY: We, the U.S. Fish and Wildlife Service (Service), designate critical habitat for the federally threatened Astragalus magdalenae var. peirsonii (Peirson's milkvetch) pursuant to the Endangered Species Act of 1973, as amended (Act). We designate a total of approximately 21,836 acres (ac) (8,848 hectares (ha)) of critical habitat in Imperial County, California.

SUMMARY: Interior Department, Fish and Wildlife Service,

SUPPLEMENTAL INFORMATION

Please see the proposed rule for critical habitat for Astragalus magdalenae var. peirsonii for a discussion on critical habitat providing little additional protection to species, role of critical habitat in implementing the Act, and the procedural and resource difficulties in designating critical habitat (68 FR 46143).

Background

For a general discussion of the role of critical habitat in implementing the Act, background information on the biology of Astragalus magdalenae var. peirsonii, and a description of previous Federal actions, including our determination that designating critical habitat for this species is prudent, please see our August 5, 2003, proposed rule (68 FR 46143). On November 15, 2001, the Center for Biological Diversity and California Native Plant Society filed a lawsuit in the U.S. District Court for the Southern District of California challenging our determination not to designate critical habitat for eight desert plants, including Astragalus magdalenae var. peirsonii (Center for Biological Diversity et al. v. Norton, No. 01 CV 2101). A second lawsuit also asserting the same challenge was filed on November 21, 2001, by the Building Industry Legal Defense Fund (Building Industry Legal Defense Fund v. Norton, No. 01 CV 2145). On July 1, 2002, the court ordered the Service to complete a review of the prudency determination and, if prudent, to finalize critical habitat for the plant on or before July 28, 2004. On April 6, 2004, we published a notice of availability of the draft economic analysis for the designation of critical habitat and reopened the comment period for the proposed rule and draft economic analysis. This second comment period closed on May 6, 2004.

Summary of Comments and Recommendations

We requested written comments from the public on the proposed designation of critical habitat for Astragalus magdalenae var. peirsonii in the proposed rule published on August 5, 2003 (68 FR 46143). We also contacted appropriate Federal, State, and local agencies; scientific organizations; and other interested parties and invited them to comment on the proposed rule. During the comment period that opened on August 5, 2003, and closed on October 6, 2003, we received 23 comment letters directly addressing the proposed critical habitat designation: 2 from peer reviewers, 1 from a Federal agency, and 20 from organizations or individuals. During the comment period that opened on April 6, 2004, and closed on May 6, 2004, we received 10 comment letters directly addressing the proposed critical habitat designation and the draft economic analysis. Of these latter comments, 1 was from a peer reviewer, 1 from a Federal agency, and 8 were from organizations. Eighteen commenters supported the designation of critical habitat for A. magdalenae var. peirsonii and six opposed the designation. Nine letters included comments or information, but did not express support or opposition to the proposed critical habitat designation. Comments received were grouped into three general issues specifically relating to the proposed critical habitat designation for A. magdalenae var. peirsonii, and are addressed in the following summary and incorporated into the final rule as appropriate. We did not receive any requests for a public hearing.

Peer Review

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

Peer Review Comments

Comment 1: One commenter supported the model used to propose critical habitat for Astragalus magdalenae var. peirsonii, but pointed to the need for using metapopulation approaches, experimental approaches, and data from ecologically similar species. The commenter suggested future approaches for modeling, monitoring, and research.

Our Response: We agree that having the results of these modeling and research efforts would improve the process of delineating critical habitat, however, such data is not available. The suggested approaches also may have a benefit in developing a recovery plan or management and conservation plans for Astragalus magdalenae var. peirsonii.

Comment 2: The proposed rule cites the finding by Romspert and Burk (1979) that older plants were the primary seed producers and that plants that become reproductive in the first season do not make significant contributions to the seed bank. However, Phillips and Kennedy (2002) concluded that firstyear plants can have a significant effect on the seed bank.

Our Response: Firstyear plants that flower and set seeds likely contribute to the seed bank. In a comparison between the mean number of fruits from older and younger plants, Phillips and Kennedy (2002) found that older plants had a mean of 171.5 fruits compared with an estimated 5 fruits for firstyear plants. With an average of 14 seeds per fruit (Barneby 1964, TOA 2001), younger plants could produce 70 seeds while older plants could produce almost 2400 seeds per plant. Consequently, both older and younger plants that
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flower and set seeds are needed to maintain the population.

Comment 3: One commenter indicated a seed bank analysis should have been completed for areas included in critical habitat on the basis of the probability of seeds being present in areas contiguous to, and having habitat continuity with, areas where Astragalus magdalenae var. peirsonii plants have been known to occur.

Our Response: We considered the work by Phillips and Kennedy (2002, 2003) on the seed bank for A. magdalenae var. peirsonii in assessing areas to include as critical habitat. Their work suggests that the seed bank is present in areas contiguous to and having habitat continuity where A. magdalenae var. peirsonii is known to occur. Their work further supported the inclusion of gaps between transects and cells in the essential habitat model where no standing plants of A. magdalenae var. peirsonii were observed.

Comment 4: The critical habitat map should be revised to include only substantial occurrences of the plant, not isolated occurrences, and connections between these areas. The proposed boundaries appear to include the entire dune system and much unoccupied, unfavorable habitat, particularly in Subunit C and Subunit D.

Our Response: Please see our responses to Public Comments Issues 1 and 2.
Public Comments

Issue 1: Biological Justification and Methodology

Comment 1: One commenter indicated we apparently identified all areas that may be occupied by Astragalus magdalenae var. peirsonii and included them in the proposed critical habitat designation without identifying why they are essential to the conservation of the species.

Our Response: We did not identify and propose critical habitat for all areas that may be occupied by Astragalus magdalenae var. peirsonii. For example, portions of the areas between Subunits A and B (south of Highway 78), between Subunits B and Subunits C and D (north and south of Interstate 8), and between Subunits C and D likely support low densities of standing plants, root crowns, or seed bank where the habitat is suitable. The gaps between Subunits A, B, C, and D were not proposed as critical habitat because these areas were not considered essential to the conservation of A. magdalenae var. peirsonii. We also state in the proposed rule that ``Outlier occurrences evidenced only by WESTEC 1977 were not included because of the age of the report and the lack of substantiation by more recent BLM surveys.'' (68 FR 46149). For the areas that were proposed as critical habitat, we provide a discussion of the essential habitat model and the use of the model to determine and justify those areas essential to the conservation of A. magdalenae var. peirsonii. See also our response to Comment 4.

Comment 2: One commenter suggested that areas where plants have not been mapped should be excluded.

Our Response: In the proposed rule, we state that ``Surveys conducted by BLM indicate variability in occurrences of standing plants from year to year'' and ``if standing plants were not found in a particular grid cell during a survey, but were recorded as present'' in that same grid cell in other survey years, we concluded that the grid cell was occupied (68 FR 46150). Not unexpectedly, gaps occur between transects because they were randomly selected across the length of the Algodones Dunes. We analyzed the gaps between transects to determine whether to include the intervening areas in the development of the essential habitat model. We state in the proposed rule that ``grid squares where this plant has not been encountered are included as critical habitat if they are contiguous with grid squares where the plant has been found and possess the primary constituent elements'' (68 FR 46151). Moreover, surveys conducted by Thomas Olson and Associates (TOA) (2001) filled in gaps between BLM's surveyed transects and grid cells. Thus, we proposed and designated critical habitat where plants were not mapped.

Comment 3: Various commenters indicated we should have included all of the Algodones Dunes.

Our Response: Astragalus magdalenae var. peirsonii has a limited distribution within the Algodones Dunes. Certain areas within the Algodones Dunes, such as areas characterized by desert pavement or by creosote bush scrub, do not support A. magdalenae var. peirsonii. The gaps between Subunits A, B, C, and D were not proposed as critical habitat because these areas were not considered essential to the conservation of A. magdalenae var. peirsonii (see response to Comment 1). Developed areas, OffHighway Vehicle (OHV) staging areas, and disturbed areas along roadways were not proposed as critical habitat because these limited areas no longer support an intact active sand dune system with natural expanses of slopes and swales (see response to Comment 6). Consequently, the entire Algodones Dunes was not proposed or designated as critical habitat.

Comment 4: Commenters indicated the proposed critical habitat does not adequately provide for habitat connectivity and recovery by not including large, wellconnected reserves. They stated that we should have followed conservation biology principles of reserve design to provide corridors for connectivity among the critical habitat subunits, or included all of the current and historical range of A. magdalenae var. peirsonii in critical habitat.

Our Response: Consistent with the principles of conservation biology, Subunits A and B are relatively large contiguous blocks of habitat that encompass the most important areas identified by our essential habitat model. Moreover, we stated in the proposed rule that ``Based on observations of unimpeded sand and wind movement across existing paved roads, we did not expect that the paved roads would represent a barrier to the dispersal of the fruits and seeds of Astragalus magdalenae var. peirsonii,'' (68 FR 46150) and the ``discontinuities associated with the highways are likely traversed occasionally by mature fruits dispersed by the wind as well as by pollinators.'' (68 FR 46152). Therefore, we do not believe that we need to provide, in the critical habitat designation, corridors for connectivity among the critical habitat Subunits A and B or that our designation of critical habitat does not follow the principles of conservation biology.

Comment 5: The proposed rule did not adequately explain why areas were excluded, including unoccupied habitat, developed areas, OHV staging areas, disturbed areas along roadways, areas between the southern areas (Subunit C and Subunit D), and areas connecting the southern and northern subunits.

Our Response: We did not propose critical habitat in areas that did not meet the definition of critical habitat under section 3(5)(A) of the Act. Developed areas, OHV staging areas, and disturbed areas along roadways were not proposed as critical habitat because these limited areas no longer support an intact active sand dune system with natural expanses of slopes and swales. For example, we state in the proposed rule that ``Significant impacts from OHV use on A. magdalenae var. peirsonii have been observed at and near OHV staging areas'' (68 FR 46145) and we believe these OHV staging areas no longer provide the primary constituent elements for this species. The areas between Subunits C and D and areas
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connecting the northern subunit (Subunit A) and southern subunits (Subunits B, C, and D) were not proposed as critical habitat because these areas were not considered essential to the conservation of A. magdalenae var. peirsonii. See our response to Comment 4 for our explanation that these areas were not essential to the conservation of A. magdalenae var. peirsonii.

Comment 6: One commenter expressed the opinion that, although OHVs may destroy individual plants, the ``churning'' by OHVs aids the propagation of seeds.

Our Response: The commenter did not provide any additional information or data to support their opinion that ``churning'' by OHVs aids in the propagation of seeds. We were unable to incorporate this suggestion in the final rule.

Comment 7: No genetic information or population size estimates are included in the proposed rule. There is no ``correct'' demographic model that incorporates the spatial and temporal complexity exhibited by Astragalus magdalenae var. peirsonii.

Our Response: Critical habitat designations are based on the best available information. Genetic information, population size estimates, and demographic models are not currently available. If this type of information became available, it would be helpful in the development of a recovery plan and management and conservation plans for this species.

Comment 8: One commenter stated Astragalus magdalenae var. peirsonii is not in danger of going extinct and grows in several other areas. The commenter provided a Web site printout suggesting this species may occur in or near Joshua Tree National Park.

Our Response: Astragalus magdalenae var. peirsonii is listed as a ``threatened'' species. The term ``threatened species'' means any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. In contrast, the term ``endangered species'' means any species which is in danger of extinction throughout all or a significant portion of its range. A search of official Web sites for Joshua Tree National Park and the National Park Service provides no known locations of this plant on any National Park Service lands. Two plant lists for Joshua Tree National Monument (now Park) also did not reference this plant. The Algodones Dunes is the only location where we have confirmed the current existence of A. magdalenae var. peirsonii in the United States.

Comment 9: The acreages for each of the critical habitat subunits were not provided in the proposed rule.

Our Response: We have included the acreages for each subunit in the final critical habitat designation.

Issue 2: Legal and Procedural

Comment 10: The North Algodones Dune Wilderness is a 32,000acre preserve for Astragalus magdalenae var. peirsonii, which should be considered in all decisions about critical habitat and listing for species found in the wilderness area. Subunit A should be removed from critical habitat because it is included in the wilderness area and already protected from most human contact. Subunit B, which includes the middle dune areas that have intense management efforts, other areas of habitat considered marginal for A. magdalenae var. peirsonii, and areas having only small stands of the species also should be removed from critical habitat designation.

Our Response: The North Algodones Dune Wilderness was designated a wilderness area to protect a number of rare and endemic plant and animal species, including Astragalus magdalenae var. peirsonii. The existence of A. magdalenae var. peirsonii in this designated wilderness area was considered when listing this species as threatened rather than endangered, as was originally proposed (57 FR 19844). Management of the North Algodones Dune Wilderness takes the form of ``minimal and subtle onsite controls and restrictions'' BLM (2003). The wilderness area is essential for the survival of Astragalus magdalenae var. peirsonii., however, the area is not specifically managed for this plant. The North Algodones Dune Wilderness was not excluded from the critical habitat designation because the habitat within the Wilderness meets the definition of critical habitat and is not otherwise appropriate for exclusion under 4(b)(2). See Comments 1 and 5 for the basis for other areas being included or excluded in the critical habitat designation.

Comment 11: The BLM's Recreation Area Management Plan (RAMP) does not address the speciesspecific management needs and measures for Astragalus magdalenae var. peirsonii.

Our Response: As noted in the proposed rule, the RAMP does not include active management for Astragalus magdalenae var. peirsonii. Consequently, BLM lands covered by the RAMP are included in the critical habitat designation. The RAMP includes an intensive monitoring program for A. magdalenae var. peirsonii that is being implemented by BLM. Based on this monitoring program, management needs for this species will be better understood. The RAMP outlines the management of the Imperial San Dunes Recreation Area to maximize recreational opportunities. Monitoring of Peirson's milkvetch is a component of this RAMP.

Comment 12: The Bureau of Reclamation stated that a 1milelong, 1,000footwide area along AllAmerican Canal in Critical Habitat Subunit D should be exempted from the critical habitat designation. The Bureau of Reclamation received a Biological and Conference Opinion of the AllAmerican Canal Lining Project, dated February 9, 1996.

Our Response: Subunit D was not carried forward to the final designation of critical habitat because of the relatively small size and separation from the other critical habitat subunits. We considered the most important areas for Astragalus magdalenae var. peirsonii to extend along the central westerly spine of the Algodones Dunes. The previously proposed Subunit D was located along the easterly edge of the main sand dune formations at the southern end of the Algodones Dunes. In general, low numbers of Astragalus magdalenae var. peirsonii were found in the vicinity of the former Subunit D. The previously proposed Subunit D was also divided by the AllAmerican Canal (Canal), with the majority of the subunit occurring northeast of the Canal. The Canal likely acts as a barrier to the dispersal of windblown seed and seed capsules, thereby isolating the northeast section of the former Subunit D from the rest of the Algodones Dunes. Thus, we determined that subunit D is not essential to the conservation of Astragalus magdalenae var. peirsonii. While this area is not designated as critical habitat, Federal agencies still have the requirement to consult with the Service under section 7 of the Act for their actions that may affect Astragalus magdalenae var. peirsonii.

Comment 13: Since all existing data show no historic or recent decline in the species, what constitutes recovery of the species?

Our Response: The data collected by BLM demonstrates a high degree of annual variability in the number of Astragalus magdalenae var. peirsonii plants observed during their surveys. The high variability is influenced by several factors, including rainfall patterns within the Algodones Dunes. For example, BLM counted 5,064 plants in 1998 (higher than average rainfall) and 942 plants in 1999 and 86 plants in 2000 (both years with lower than average rainfall) along these transects. [[Page 47333]]
Astragalus magdalenae var. peirsonii has apparently been extirpated from Borrego Valley in eastern San Diego County, not having been seen there since 1959 and not located in 1978 surveys (Spolsky 1978). The periodically low numbers and restricted range of A. magdalenae var. peirsonii make it vulnerable to threats discussed in the final rule listing this plant. BLM has initiated a largescale monitoring program for A. magdalenae var. peirsonii that will provide valuable information on population trends for this species (BLM 2003).

Recovery is defined in our regulations (50 CFR 402.02) as ``improvement in the status of listed species to the point at which listing is no longer appropriate under the criteria set out in section 4(a)(1) of the Act.'' The reasons for listing A. magdalenae var. peirsonii are detailed in the proposed (57 FR 19844) and final (63 FR 53596) rules to list the species as threatened. To achieve recovery, the threats must be eliminated, reduced, or managed to the extent that the status of A. magdalenae var. peirsonii no longer meets the definition of threatened (i.e., in danger of becoming endangered in the foreseeable future throughout all or a significant portion of its range). Objective and measurable criteria included in a recovery plan are used to determine when a species has recovered and can be delisted. A draft recovery plan for A. magdalenae var. peirsonii is currently in preparation.

Comment 14: Two commenters expressed concern that the detailed legal descriptions used to define the areas proposed for inclusion in critical habitat do not allow easy comprehension of the critical habitat boundaries.

Our Response: Our regulations (50 CFR 17.94(b) and 50 CFR 424.12(c)) set forth the requirements for describing areas included in a critical habitat designation. Although maps are included, such maps are provided for reference purposes only to guide Federal agencies and other interested parties in locating the general critical habitat boundaries. Critical habitat subunits must be described by specific limits using reference points found on standard topographic maps of the area. We are required to provide legal definitions of the boundaries. The boundaries for critical habitat are provided as Universal Transverse Mercator (UTM) North American Datum coordinates that describe the critical habitat boundaries.

Comment 15: Determination of critical habitat should be postponed until completion of the status review announced in the 90day finding (68 FR 52784) on a petition to delist Astragalus magdalenae var. peirsonii.

Our Response: Notice of the 12month finding on a petition to delist Astragalus magdalenae var. peirsonii was published on June 4, 2004 (69 FR 31523). After reviewing the best scientific and commercial information available, we found that the petitioned action was not warranted. Astragalus magdalenae var. peirsonii is retained as a threatened species under the Act.

Comment 16: One commenter expressed the opinion that the proposed critical habitat represents a closure of the area to OHVs and constitutes a ``taking.'' Several commenters also seemed to believe that the designation would result in these areas being closed to OHVs and other human activity.

Our Response: Proposed or final designation of critical habitat does not of itself require that an area, including any of the BLM management areas within the Algodones Dunes, be closed to any particular activity. In the case of Federal lands, which constitute the overwhelming majority of the proposed and designated critical habitat, or federally funded or permitted activities, the designation requires the Federal agency in question to consult with the Service under section 7 of the ESA as to whether any activity which might adversely modify the critical habitat would in fact do so.

A section 7 consultation on the impact of BLM management of the Dunes, including the RAMP, on the Astragalus magdalenae var. peirsonii, and a conference on the proposed critical habitat, has been underway for some time. However, as of the date of this designation of critical habitat, it has not been concluded. We therefore do not know whether any closures might result from the consultation and conference, or whether there might be subsequent litigation, which might lead to closures of some or all of the area. All we can say at this time is that the designation of critical habitat does not of itself require closures to OHV or other human uses.

On the other hand, the designation does not affect land ownership or establish a refuge, wilderness, reserve, preserve or other type of conservation area. It does not affect activities on private land unless the landowner requires a Federal permit, funding or other assistance to conduct the activity. We prepared a Takings Implications Assessment for the proposed and final designations of critical habitat for Astragalus magdalenae var. peirsonii as required by Executive Order 12630 (``Government Actions and Interference with Constitutionally Protected Private Property Rights''). These assessments concluded that the designation of critical habitat did not pose significant takings implications.

Comment 17: One comment letter recommended we provide more maps showing clearer details of proposed critical habitat, the historic range of Astragalus magdalenae var. peirsonii, and a detailed political map of the area.

Our Response: The maps we publish are limited by the printing capabilities of the Federal Register and the Code of Federal Regulations. We can provide more accurate maps on request, as well as answer questions regarding particular areas. Please contact the Carlsbad Fish and Wildlife Office (see ADDRESSES section above) for assistance.

Comment 18: One commenter expressed neither support nor opposition to the proposed designation of critical habitat, but requested a ``plan'' and map for the proposed critical habitat.

Our Response: We do not develop management plans or recovery plans for designated critical habitat. The proposed and final rules include maps and legal descriptions of the critical habitat. See the response to Comment 17 regarding availability of more detailed maps.

Comment 19: One commenter recommended that we give full consideration to the threats from OHVs in the final rule.

Our Response: Critical habitat designation identifies areas essential to the conservation of the species that may require special management considerations (see Comment 1). Critical habitat does not directly address threats to the species. Instead, Federal agencies must consult with the Service on their actions that may affect critical habitat and ensure that their actions do not destroy or adversely modify critical habitat.

Issue 3: Economic Issues

Comment 20: One commenter stated the ``economic analysis'' in the notice of proposed rulemaking was incomplete and inadequate. Other commenters indicated the economic analysis must be included in the proposed rule, and the proposed rule should be revised to include an economic analysis and published again for review. Commenters were concerned that the public would not be able to comment on the economic analysis.

Our Response: The proposed rule did not contain an economic analysis. As is our usual practice because of the urgency of court orders the proposal indicated that we would announce the
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availability of the draft economic analysis at a later date and would at that time seek public review and comment on the draft economic analysis. We published a notice of availability for the economic analysis in the Federal Register on April 6, 2004. That notice also reopened the comment period on the proposed rule and the draft economic. The comment period closed on May 6, 2004.

Comment 21: Commenters suggested that the benefits, such as non consumptive uses, resulting from the designation of critical habitat to protect Astragalus magdalenae var. peirsonii should be taken into account.

Our Response: We are unable to quantify the benefits of non consumptive uses resulting from critical habitat. While the ISDRA offers opportunities for nonOHV recreation, such as hiking and horseback riding, historical use patterns indicate that the number of individuals participating in these activities is far less than those involved in OHVbased recreation. As such, the analysis focuses on economic impacts to OHV enthusiasts and OHVrelated businesses. The published economics literature has documented that real social welfare benefits can result from the conservation and recovery of endangered and threatened species. Regional economies and communities can benefit from the preservation of healthy populations of endangered and threatened species, and the habitat on which these species depend.

In Executive Order 12866, the Office of Management and Budget (OMB) directs Federal agencies to provide an assessment of costs and benefits of proposed regulatory actions. However, in its guidance for implementing Executive Order 12866, OMB acknowledges that often it may not be feasible to monetize, or even quantify, the benefits of environmental regulations. Where benefits cannot be quantified, OMB directs agencies to describe the benefits of a proposed regulation qualitatively. Given the limitations associated with estimating the benefits of critical habitat for Astragalus magdalenae var. peirsonii, the Service believes that the benefits of critical habitat are best expressed in biological terms that can be weighed against the expected cost impacts of the rulemaking. Thus, we have qualitatively described the benefits in the final rule and we have not used the benefits of nonconsumptive uses in our economic analysis.

Comment 21: One commenter objected to a statement that the proposed rule would not impose a cost on the OHV industry.

Our Response: The economic analysis considered a No Closure Scenario (BLM Management Areas are not closed to OHV recreation as a result of critical habitat) and a Closure Scenario (BLM Management Areas are closed to OHV recreation as a result of critical habitat) to estimate the economic costs of designating critical habitat. Under the No Closure Scenario, the annual efficiency impacts associated with future Astragalus magdalenae var. peirsonii protection associated with administrative and project modification costs only (such as a Federal agency compliance with section 7 of the Act) would be approximately $0.6 million. Under the No Closure Scenario, losses to OHV users would be zero.

Under the Closure Scenario, the efficiency effects would be associated with administrative costs, project modification costs, and consumer surplus losses to OHV users. That is, efficiency effects would be the sum of the administrative and project modification costs ($0.57 million) and the consumer surplus contribution associated with the affected regions. If all of the areas designated as critical habitat within the Imperial Sand Dunes Recreation Area (ISDRA) were closed to OHV use, the efficiency effects would range from $9.5 million per year to $10.5 million per year ($0.57 million per year in administrative and project modification costs plus consumer surplus impacts ranging from $8.9 million per year to $9.9 million per year) (2003 dollars). If all of the areas designated as critical habitat within the ISDRA were closed to OHV use, the regional economy would see an upper bound reduction in output of $55 million to $124 million in year 2013 (2003 dollars), and a potential loss in employment of 1,207 to 2,585 jobs. If no closures were to take place, the lower bound regional economic impact would be zero.

For the regulatory flexibility analysis, we identified the OHV industry as being the only small entities that could be affected by the designation of critical habitat. The designation of critical habitat only affects Federal agencies that must consult on impacts to critical habitat under section 7 of the Act. An analysis of past section 7 consultations revealed that business activities of the OHV industry have not directly triggered section 7 consultations in the past and are unlikely to trigger future section 7 consultations. Therefore, we concluded that critical habitat would not create new costs for small entities to comply with the designation.

Comment 22: One commenter believes that the range of forecast economic impacts is too wide (i.e., scenarios in the DEA range from no closure to blanket closures of certain areas).

Our Response: Given the uncertainty in the nature and scope of future limitations of OHV use in the Imperial Sand Dunes Recreation Area (ISDRA) associated with PMV conservation measures, the analysis provides impact measures under a range of scenarios, from no closures to complete closure. As proposed in the 2003 Biological Opinion issued by the Service on management of the ISDRA, BLM has initiated an extensive monitoring program for the PMV. BLM proposes to reinitiate consultation with the Service in four years based on information obtained from monitoring or studies. BLM also proposes to reinitiate sooner than four years if the PMV population in any Management Area falls to 50 percent of the baseline level in a subsequent year with comparable rainfall at or above the longterm mean (Service, 2003). This future consultation has the potential to result in additional management actions to protect the PMV, although currently no actions are anticipated that would reduce OHV opportunities or adversely impact the regional economy. Given uncertainties related to future management decisions and biological factors, narrowing the range of potential scenarios is not possible at this time. As a result, the analysis can be used to determine the social welfare and regional economic impacts that might occur under a range of potential future management actions related specifically to closure scenarios. Both technical reviewers of the draft report concluded that this approach is appropriate given the uncertainty associated with future policy decisions.

Comment 23: Several commenters note that the analysis underestimates expenditures made by ISDRA visitors. Commenters provide estimates of expenditures per trip ranging from $1,000 to $2,000.

Our Response: The analysis recognizes that OHV users incur large triprelated expenses when visiting the ISDRA. However, the highend estimates reported by several commenters may not represent the average of expenditures across all groups who visit the dunes, and overstates the expenditures made by the average visitor within the two counties included in the analysis.

The $265 to $515 per trip expenditure range used in the analysis is derived from an American Sand Association newsletter (dating May 2003), and is
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intended to represent an average across the hundreds of thousands of trips taken to the ISDRA each year. Clearly some visitors spend more; however, the range used is intended to represent an average. More important, the expenditure range applied in the DEA is used to represent expenditures by visitors solely within Imperial and Yuma Counties. BLM and OHV stakeholder groups indicate that many ISDRA visitors purchase goods and services outside of Imperial and Yuma Counties (e.g. gas, groceries, supplies, and equipment are purchased within counties of origin featured in Exhibit 31 of the report).

The report's trip expenditure assumptions are similar to estimates used in an economic study conducted by BLM in its Final Environmental Impact Statement for the Imperial Sand Dunes Recreation Area Management Plan (May 2003). The BLM study's estimate of $260 in expenditures per household OHV trip is taken from a California Department of Parks and Recreation OffHighway Vehicle study. This estimate is assumed to represent the portion of expenditures spent within the local economy, consisting of Imperial and Yuma Counties. The highend expenditureper trip estimates provided by commenters likely do not represent purchases made entirely within the counties modeled in the analysis.

Technical reviewers of the DEA note that visitor expenditure estimates are critical to estimating the regional economic impacts and support the assumptions employed within the DEA. Moreover, expenditures generated by applying the $250$515 range to estimated number of ISDRA trips per year are reasonable when viewed in the context of the local economy. While overall estimates of expenditures per trip remain unchanged from the DEA, the final report has been revised to include discussion of the highend trip expenditures incurred by ISDRA OHV users (Section 4.1.5).

Comment 24: Several commenters note that analysis does not address impacts to OHV and OHVrelated equipment manufacturers within Imperial and Yuma Counties.

Our Response: BLM and OHV user groups have indicated that most ISDRA visitors purchase OHVs and other recreational vehicles in areas outside of Imperial and Yuma Counties (i.e. in counties of origin depicted in Exhibit 31). The analysis recognizes, however, that OHV businesses within Imperial and Yuma Counties benefit directly from OHV recreation at the ISDRA. Section 3.2.2 states, ``Several businesses that operate within Imperial and Yuma Counties are dependent on the recreational activities that occur within the ISDRA * * * major towns in the counties have a number of small businesses that sell OHVs and OHV accessories and services and market to both local and tourist populations. In addition, a number of small businesses exist within the geographical boundaries of the ISDRA itself, catering exclusively to dune visitors. Any reduction in visitation is likely to adversely impact these local businesses''.

Potential impacts to local businesses selling OHV equipment, supplies and services in Imperial and Yuma counties are examined in the analysis of regional economic impacts (Exhibit 413). In 2003, direct expenditures incurred by ISDRA recreators on OHV equipment, supplies, and services are estimated to be $69.2 million (on average $194.60 per trip multiplied by an estimated 355,704 trips). Information on the number of ISDRA visitors who live in and purchase OHVs and OHVrelated vehicles within Imperial and Yuma Counties is not available. Therefore, data do not exist to accurately estimate potential reductions in OHV purchases made within Imperial and Yuma Counties given possible changes in ISDRA management. The report, however, does recognize the potential for impacts to these regional OHV retailers.

While overall cost estimates remain unchanged from the DEA, the report has been revised to incorporate additional information on OHV. Specifically, local governments and OHV groups have provided information on OHV retailers within Imperial and Yuma Counties.

Comment 25: Several commenters stated that the report underestimates or excludes expenditures incurred through purchasing OHVs and OHVrelated equipment, including trailers, haulers, specialized dune transportation equipment.

Our Response: The above response describes why potential economic impacts to regional OHV retailers were not quantified in the analysis. While overall cost estimates within the report remain unchanged, Section 3.2.1 of the report has been revised to describe additional information on investment in OHV equipment.

Comment 26: One commenter questioned whether the regional economic analysis incorporates impacts to permitted vendors within the ISDRA.

Our Response: The analysis addresses potential impacts of decreased expenditures in industries related to OHV recreation by utilizing IMPLAN, a software package that translates initial changes in expenditures into changes in demand for inputs to affected sectors. The sectors examined include fuel, food, camping supplies, medical goods and services sales and equipment repairs within Imperial and Yuma Counties. To the extent that permitted vendors are included as part of these sectors and are taxed by local governments, impacts to them are captured in the regional economic impact analyses of these industries.

Comment 27: One commenter notes that current closures in the Algodones Dunes are creating an adverse economic impact that is not being defined within this draft report.

Our Response: The analysis addresses impacts from past and current closures. Section 4.1.6, ``Summary of Past Impacts'', provides estimates of consumer losses and regional economic impacts stemming from the 2001 temporary closures.

Comment 28: Several commenters note that the report underestimates lost revenues within Imperial and Yuma Counties. One commenter notes that a former BLM economic study underestimated economic contributions associated with ISDRA visitation. Another commenter states that the textbox in the Executive Summary underestimates the economic contribution of the ISDRA to Imperial County.

Our Response: The analysis calculates a range of economic contributions associated with ISDRA visitation assuming high and low visitation projections and high and low expenditures per trip. The report first calculates the economic contribution of the entire ISDRA and then attempts to distinguish contributions associated with visitation in areas proposed as critical habitat. Exhibit ES6, Figure 42 and Exhibit 414 summarize contributions of OHVrelated
expenditures and contributions by each management area and proposed critical habitat. The value generated by Glamis alone within Yuma County is as high as $17.36 million per year. Placed in the context of both counties' annual taxable sales, regional economic contributions of the ISDRA comprise a sizable portion of the two counties' economies.

The textbox within the Executive Summary examines the current economic value generated by OHV use within the Glamis Management Area relative to the county's revenues. Total expenditures generated from OHV use within the entire ISDRA in 2003 can be calculated by multiplying current visitation by assumed expenditures per trip. Exhibit 414 also provides total
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expenditures generated by the entire ISDRA by management area assuming 2013 visitation. The textbox has been clarified to highlight the focus on the Glamis Management Area.

Comment 29: Several commenters note that the estimated impacts should be placed in the context of OHVrelated business sales and not the entire region's economy. One commenter requests that the analysis include a definition of ``significant'' when comparing reported economic impacts on local economies. Another commenter notes that sales taxes lost to the region would equate to a 5 percent loss in workforce and small businesses that rely on OHV recreation would cease to exist. Finally, one commenter notes that the analysis does not adequately address how the estimated job losses (of up to 2,585 jobs) will impact a region that already experiences high unemployment.

Our Response: Response to comments above addresses potential impacts to small businesses in the twocounty area. The analysis has been revised to include estimated losses as a percent of OHVrelated businesses and sales, specifically sales within the retail trade, accommodation, and food services sectors within the two counties (Exhibits ES5 and 417). In addition, Section 4.2.6 within the report has been revised to further discuss how potential losses in revenues, employment, and taxes may impact the local economies. Note that Section 3.1.4 within the report describes the high unemployment rates prevalent in both counties and major cities within the region.

Comment 30: Several commenters note that the economic analysis does not address potential impacts to OHV trailer manufacturing and OHV accessory businesses that exist outside of Imperial and Yuma Counties. One commenter notes that OHV recreation provides approximately $9 billion to California's economy and that since the ISDRA is the most heavily used OHV area in the state, potential closures would be far greater than those estimated in the economic analysis.

Our Response: The report recognizes that OHV businesses operating outside of the primary study area (Imperial and Yuma Counties) have the potential to be impacted by any limitations on OHV activity within the ISDRA, provided that limitations discourage users from purchasing OHVs and related equipment (Section 3, paragraph 89). These potential impacts are difficult to analyze as no data exist to model where OHV enthusiasts from the greater California and Arizona region purchase vehicles and other equipment, and how these purchases will change in response to closures within the ISDRA.

First, as stated in paragraph 89, ``OHVrelated businesses located outside of Yuma and Imperial Counties may experience a lesser impact than those within these counties, since OHV enthusiasts may decide to visit other OHV areas in California, Arizona, and neighboring states.'' Technical reviewers of the report agree that if an area is closed, the visitor may not give up OHV recreational experiences but instead may seek other places to visit. By not taking into account this behavioral phenomenon, generated impact estimates could be greatly overestimated.

Second, while OHV and related equipment manufacturers may experience impacts within the greater California and Arizona area, these impacts are anticipated to be small relative to the overall size of these counties' economies. As stated in paragraph 89, ``This analysis does not quantify the expenditures OHV users make on vehicles or related equipment because these purchases are likely made over a broader geographic area.'' Potential changes in OHVrelated expenditures are not expected to have a significant impact outside of Imperial and Yuma Counties, because the majority of these counties are large, with diverse economies (e.g. Los Angeles).

Finally, losses to businesses within the twocounty area from decreased ISDRA visitation are unlikely to be replaced by expenditures on other goods and services of the same order of magnitude. However, impacts to OHVrelated businesses in other areas (e.g. origin counties) will likely be offset by expenditures on other goods and services in those regions, even if OHV use declines.

The most recent OHV survey conducted by the California OffHighway Motor Vehicle Recreation Division in 2002 estimates the annual economic impact of OHV recreation in California at $3.049 billion (CA Off Highway Motor Vehicle Recreation Division, 2001). The extent that use limitations within the ISDRA discourage OHV users from the greater economic study area from purchasing OHVs and OHVrelated equipment, OHV businesses within the broader geographic area are likely to be impacted.

Comment 31: One commenter notes that decreases in revenues within Imperial and Yuma Counties as a result OHVuse restrictions may increase revenues in other counties that provide sand dune opportunities that do not host rare species.

Our Response: The analysis acknowledges within Section 3 that, ``* * * OHVrelated businesses located outside of Yuma and Imperial may experience a lesser impact than those within these counties, since OHV enthusiasts may decide to visit other OHV areas in California, Arizona, and neighboring states''. Exhibit 38 within the report provides examples of substitute sites available to OHV users and notes this occurrence as a key assumption in Exhibit ES7. However, with over 83,000 acres currently open to OHV use and 132,870 acres available once the temporary closures are lifted, the ISDRA remains one of the largest dune systems available for motorizedrecreation in the region. Three sites, Ocotillo Wells, Superstition Mountain, and Dumont Dunes, closest to the ISDRA provide for recreation.

While decreased expenditures within Imperial and Yuma Counties may be offset by increased expenditures, though difficult to quantify, in other OHV areas, understanding potential impacts to this region is critical to understanding the potential impacts of any changes in OHV use at the ISDRA. Several businesses that operate within the region rely heavily on income generated by OHVbased recreation. Reduced visitation resulting in revenue, employment and tax losses may pose considerable burdens to local communities.

Comment 32: One commenter noted that visitation is not evenly distributed throughout the ISDRA: the inner areas of the dunes are the most popular, and the inner areas are what draw visitors to the dunes. Another commenter notes that the analysis inflates impacts by assuming visitation is evenly distributed within each management area when ``highest use areas were already excluded''. Another commenter notes that assuming visitation is evenly distributed within each management area is unrealistic because of ``the known distributional patterns of motorized recreation over the OHV accessible areas of the dunes''.

Our Response: The analysis recognizes that highuse, developed, staging, and camping areas that are unlikely to contribute to the conservation of the species have been excluded from the proposed designation. The analysis also agrees that the inner portions of the dunes may be more attractive to some users (Sections 2.3.1; Section 4, paragraph 121; and Section 4.1.1). However, while the inner portions of the dunes may draw many users to the dunes, these areas are more remote and are therefore likely to experience less intensive
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visitation (i.e., such visitation may require specialized equipment).

It is not possible, using existing data, to predict the percentage of OHV users who visit areas of the ISDRA that are proposed for critical habitat. Lacking detailed data and user patterns and to offset conflicting attitudes towards visitation distribution, the report models visitation based on BLM visitor counts and assumes an equitable distribution of visitation within each management area. To the extent that areas proposed for designation are less or more popular with OHV users, this analysis could overstate or understate impacts by over or underestimating the number of trips that could be affected by the designation.

Comment 33: One commenter suggests that any potential limitations on OHV use may displace visitation to other parts of the season (users might spread usage over other times, resulting in similar usage and economic expenditures). Another commenter notes that the analysis cannot assume lasting impacts of any future closures on visitation levels within the ISDRA.

Our Response: The analysis recognizes that OHV limitations in the past may have resulted in a redistribution of visitation over the recreation season. Section 4.1.1 states that that in the years subsequent to the temporary 2001 closures, BLM ``documented an increase in visitation during traditionally offpeak weekends, likely a result of OHV recreationists seeking a lesscrowded ISDRA experience * * * whether visitation to the ISDRA declined as a result of the closures is debated.''

Data are not available to model intertemporal substitution by ISDRA visitors given closure of one or more of the management areas. To determine the economic impact of past limitations on OHV recreation, the analysis assumes that OHVusers who would otherwise recreate at the closed ISDRA management areas would limit or refrain from visits to the dunes. Thus, the analysis can be used to understand the upperbound social welfare and regional economic impacts under a variety of closure scenarios.

Comment 33: Several commenters note that ISDRA visitation actually increased rather than declined subsequent to the 2001 closures and that it is erroneous to conclude that visitation declined by 15 percent due to the closures particularly since visitation fluctuates based on weather and other factors.

Our Response: The report acknowledges in Section 4.1.4 that the reported change in ISDRA visitation between 2001 and 2002 is not likely due to actual increased visitation but rather to refined counting methodologies employed by BLM. The analysis states that ``prior to 2002, BLM extrapolated visitation by employing ontheground and fly over estimates of vehicles during peak weekends. In 2002, BLM installed underground vehicle counters at each major ISDRA entrance point. Accordingly, accurate visitation data by management area prior to the 2002 recreation season is not available.''

The report also recognizes in Section 4.1.4, that fluctuations in annual visitation reflect a variety of factors, including economic and weather conditions. While BLM did not observe a drop in visitation subsequent to the closures, users within the OHV community expressed that visitation levels were likely impacted. The 15 percent reduction was therefore assumed to represent visitation in the areas slated for temporary closure. To understand the maximum social welfare and regional economic impacts of a closure, the DEA assumed that under closures OHV users who preferred to recreate in the closed areas would choose to not visit the dunes or make fewer trips per year. In Exhibit 48, this assumption of a 15 percent reduction is listed as a key assumption employed in the analysis of past economic impacts.

Comment 35: One commenter notes that the DEA does not consider economic costs associated with managing OHV activities at the ISDRA, including law enforcement required during highuse weekends. Another commenter notes that the analysis overlooks costs inflicted upon public safety by OHV use. Finally, a commenter remarks that it is incorrect to assume that closures are associated with cost savings to public agencies. (CNPS, BN, BLM)

Our Response: The analysis addresses costs associated with the public provision of onsite services at the ISDRA within Section 3.2.3. As stated:

Accommodating the millions of visitors that visit the ISDRA each year requires the provision of additional services and onsite infrastructure by both BLM and local government agencies * * * (m)oreover, the high visitation that occurs at the ISDRA during holiday weekends between March and October necessitates the provision of additional enforcement and emergency services. During highuse holiday weekends, BLM employs as many as 100 officers from state, local, and federal agencies to patrol the dunes. In the ISDRA Business Plan, BLM anticipates incurring annual costs of up to $3.12 million related to law enforcement ($500,000), emergency ($280,000), and additional holiday staffing ($2.34 million) * * * The Imperial County Sheriff's Office has also led a coalition of law enforcement agencies over the past three years to enforce legal behavior and provide for public safety at the dunes. In December 2003, the Sheriff's Office was granted approximately $750,000 for OHV law enforcement and emergency services at the ISDRA by the California OffHighway Motor Vehicle Recreation Commission. Any reduction in future visitation at the ISDRA is potentially associated with public costs savings in expenditures related to providing onsite
infrastructure, enforcement, and emergency services at the dunes. However, data are not available to estimate the extent of these cost savings; as such, these cost savings are not monetized in this analysis.

Comment 37: Two commenters noted that the substitute sites listed in Figure 32 do not provide recreational opportunities provided by the ISDRA in terms of acres available for dune recreation and distance from point of origin. One commenter specified that comparable alternatives should be limited a 250 mile radius from Los Angeles or Phoenix, cities from where the majority of ISDRA users originate.

Our Response: Substitute sites were compiled from a variety of sources, including published documents and personal communication with ISDRA dune users. As visitors from the ISDRA originate from a broad geographic area, the analysis assumed a broad distribution of OHV recreation. Figure 32 has been revised to incorporate updated information on types of recreational opportunities offered by the alternative OHV recreation areas (e.g. whether sites offer dunebased recreation). Information on potential substitute sites for OHV recreation within the region is provided as a basis for comparison and does not impact cost estimates presented in the report.

Comment 38: Several comments noted that the report fails to address or minimizes the economic contribution of nonOHV recreation, overlooking the fact that nonOHV recreation may be precluded by OHV use due to safety concerns. One commenter also requested that the analysis address contributions of recreational activities associated with botanical opportunity.

Our Response: The report acknowledges the presence of nonOHV related recreational activities within the ISDRA, including hiking, horseback riding, conservation activities, and some commercial activities including filming (as stated in paragraph 6 and Section 2.3). While the ISDRA offers opportunities for nonOHV recreation, BLM has noted that these activities occur infrequently relative to OHV based recreation. Based on historical use patterns within areas open to nonmotorized recreation, nonOHV related
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activities are expected to remain relatively modest in the future.

While nonmotorized recreation is precluded in OHVrecreation areas due to safety concerns, it is difficult to determine whether closures to OHVuse would generate similar levels of visitation and expenditures by nonOHV recreational activities. Given the current disparity between the number of nonOHV trips and OHV based trips, nonOHV recreation given closures to OHVuse would likely draw several order of magnitude less visitation.

Comment 39: One commenter notes that the number of acres available to OHV use within the ISDRA reported in Figure 38 is misleading. The report presents 83,560 acres available to OHV use and the commenter notes that number should reflect acreage prior to the temporary closures, or 132,870 acres.

Our Response: Figure 38 has been revised to incorporate both temporary and permanent acreage numbers (83,560 and 132,870 acres available for OHV use).

Summary of Changes From the Proposed Rule

In the development of our final designation of critical habitat for Astragalus magdalenae var. peirsonii, we reviewed comments received on the proposed designation of critical habitat. In addition to minor clarifications and incorporation of additional information on the biology of A. magdalenae var. peirsonii, we made the following changes to the proposed designation:
(1) We did not include Subunit D in the final designation of critical habitat. Because of its relatively small size and separation from the other subunits, we do not consider it essential to the conservation of the taxon.
(2) We excluded portions of Subunit B and all of Subunit C from the final designation of critical habitat under section 4(b)(2) of the Act. (3) We modified the primary constituent elements to include the associated coadapted psammophytic (sandloving) scrub plant community that supports the whitefaced digger bee (Habropoda spp.), the primary pollinator of Astragalus magdalenae var. peirsonii (Porter 2003b). Critical Habitat

Please see the proposed rule for critical habitat for Astragalus magdalenae var. peirsonii for a general discussion on sections 3, 4, and 7 of the Act in relation to critical habitat (68 FR 46143). Methods

As required by section 4(b)(2) of the Act and regulations at 50 CFR 424.12, we used the best scientific and commercial information available to determine areas that contain the physical and biological features that are essential for the conservation of Astragalus magdalenae var. peirsonii. This included information from our own documents on this plant and related taxa; available information that pertains to the biology and habitat requirements of this taxon, including data from research and survey observations, such as WESTEC (1977), BLM surveys conducted from 1998 to 2002 (Willoughby 2000, 2001), TOA (2001), and Phillips and Kennedy (2002, 2003); the California Natural Diversity Database (2003); peerreviewed journal articles and book excerpts regarding A. magdalenae var. peirsonii, similar species, or more generalized issues of conservation biology; unpublished biological documents; site visits; and discussions with botanical experts regarding A. magdalenae var. peirsonii and related species.

The areas designated as critical habitat are occupied by Astragalus magdalenae var. peirsonii as demonstrated by repeated surveys by BLM (Willoughby 2000, 2001), and independently confirmed by other surveys (TOA 2001; Phillips and Kennedy 2002, 2003). This plant may be present as standing plants, persisting as perennial root crowns in the sand, or as seed bank in the sand. During any given year, the suitable habitat for A. magdalenae var. peirsonii may be occupied by various combinations of these three life history phases. These surveys confirm the continuity of habitat for A. magdalenae var. peirsonii along the northwesttosoutheast axis of the Algodones Dunes. The dynamics of dune morphology, local rainfall patterns and amounts, spatial distribution of the seed bank, and seed scarification each contribute to the patchy or mosaic nature of the distribution of standing plants of A. magdalenae var. peirsonii. Local rainfall patterns and amounts are likely to cause shifts in the proportions of these three life history phases. All areas designated as critical habitat contain at least one of the primary constituent elements and have been determined to be essential to the conservation of the species.

The most extensive survey of the Algodones Dunes was conducted in 1977 (WESTEC 1977). This survey used 66 transects that ran across the dunes from west to east. The presence and relative abundance of standing plants of Astragalus magdalenae var. peirsonii and four other rare psammophytic scrub species were recorded along these transects. In 1998, BLM began surveying for rare plants in the dunes repeating the methodology used by WESTEC in their 1977 survey. BLM surveyed 34 of the original 66 transects and employed a different abundance measure. The BLM conducted these surveys for 5 consecutive years (1998, 1999, 2000, 2001, and 2002) recording the presence and abundance of the rare plant taxa along these transects.

To determine the general range of Astragalus magdalenae var. peirsonii in the Algodones Dunes, we used survey information from published and unpublished documents and maps including WESTEC (1977), BLM (Willoughby 2000, 2001), and TOA (2001). WESTEC (1977) devised a grid system overlay for the Algodones Dunes. Each quadrant of the grid was approximately 0.45 mi (0.72 km) on a side. BLM reproduced this grid system to present data from their subsequent annual surveys from 1998 to 2002 (Willoughby 2000, 2001). Both WESTEC and BLM considered a grid square occupied if A. magdalenae var. peirsonii was encountered anywhere within that grid square. For comparison, we also superimposed census data included by TOA (2001) on this same grid system. We produced maps based on WESTEC (1977), BLM (Willoughby 2000, 2001), and TOA (2001) data. Because of the differences in survey methodologies and abundance classes used by these surveys, we considered each of these records to document presence or absence. Due to fluctuations in both the presence and abundance of A. magdalenae var. peirsonii from year to year, we combined the data from multiple years of survey data. Also the various surveys recorded standing plants as the only measure of occupancy, not taking into account a dormant seed bank or root crowns.

The survey efforts discussed above provided us with the data necessary to construct a model showing which regions of the Algodones Dunes represent habitat essential for the conservation of Astragalus magdalenae var. peirsonii. The model that we created used the data collected by the BLM from 1998 to 2002 as the input data and the data collected by WESTEC (1977) and TOA (2001) as a means of verifying the information generated by the mod

FOR FURTHER INFORMATION CONTACT Field Supervisor, Carlsbad Fish and Wildlife Service (telephone 760/4319440; facsimile 760/4319618).