Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat for Astragalus magdalenae var. peirsonii (Peirson's Milk-Vetch), 8748-8785 [08-545]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 31 (Thursday, February 14, 2008)]
[Rules and Regulations]
[Pages 8748-8785]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 08-545]



[[Page 8747]]

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Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



Endangered and Threatened Wildlife and Plants; Revised Designation of 
Critical Habitat for Astragalus magdalenae var. peirsonii (Peirson's 
Milk-Vetch); Final Rule

Federal Register / Vol. 73, No. 31 / Thursday, February 14, 2008 / 
Rules and Regulations

[[Page 8748]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2008-0019; 92210-117-0000-B4]
RIN 1018-AU98


Endangered and Threatened Wildlife and Plants; Revised 
Designation of Critical Habitat for Astragalus magdalenae var. 
peirsonii (Peirson's Milk-Vetch)

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), are 
designating final revised critical habitat for Astragalus magdalenae 
var. peirsonii (Peirson's milk-vetch) under the Endangered Species Act 
of 1973, as amended (Act). In total, approximately 12,105 acres (ac) 
(4,899 hectares (ha)) fall within the boundaries of the revised 
critical habitat designation for A. m. var. peirsonii. The revised 
critical habitat is located in Imperial County, California. We are 
excluding Unit 2 from this revised designation based on the 
disproportionate economic and social impacts associated with the 
designation of this unit relative to the other units designated as 
critical habitat. This final revised designation constitutes a 
reduction of 9,758 ac (3,949 ha) from our 21,863 ac (8,848 ha) previous 
final designation of critical habitat for A. m. var. peirsonii 
published in 2004.

DATES: This rule becomes effective on March 17, 2008.

ADDRESSES: This final rule is available on the Internet at https://
www.regulations.gov. In addition, the final revised rule, economic 
analysis, and maps are available at https://www.fws.gov/carlsbad/. 
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, 6010 
Hidden Valley Road, Carlsbad, CA 92011; telephone 760-431-9440; 
facsimile 760-431-5901. If you use a telecommunications device for the 
deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-
877-8339.

SUPPLEMENTARY INFORMATION: 

Background

    This final rule addresses revised critical habitat for Astragalus 
magdalenae var. peirsonii. For additional information on the taxonomy, 
biology, and ecology of this taxon, refer to the final rule listing the 
taxon as threatened, published in the Federal Register on October 6, 
1998 (63 FR 53596), the proposed and final rules designating critical 
habitat for this taxon published in the Federal Register on August 5, 
2003 (68 FR 46143) and on August 4, 2004 (69 FR 47330), respectively, 
and the proposed rule to revise critical habitat published in the 
Federal Register on July 27, 2007 (72 FR 41258). It is our intention to 
discuss only those topics directly relevant to the revised designation 
of critical habitat in this final revised rule.
    Astragalus magdalenae var. peirsonii is an erect to spreading, 
herbaceous member of the Fabaceae (legume family) (Barneby 1959, p. 
879; 1964, p. 862) that occurs on bowls, swales, and slopes of intact, 
active windblown sand dunes of the Algodones Dunes of Imperial County, 
California and the northeastern Estado de Baja California and Gran 
Desierto of northwestern Sonora, Mexico (Felger 2000, p. 300; 
Spellenberg 1993, p. 598; Willoughby 2005a, p. 2). Please refer to the 
``Primary Constituent Elements'' section below for additional 
discussion on habitat requirements of this taxon. Plants may reach 8 to 
27 inches (in) (20 to 70 centimeters (cm)) in height and develop tap 
roots (Barneby 1964, pp. 863-864) that penetrate deeply to the moister 
sand and that anchor plants in the shifting sand dunes. The root crown 
is often exposed by wind action moving the sand away from the base of 
the plants. Seeds are enclosed in fruits or pods and are either 
dispersed locally by falling out of partly opened fruits on the parent 
plant, ``salt-shaker'' style, or are dispersed further if blown across 
the sand after falling from the parent plant. Thus seeds can be 
transported from one favorable site to another, or remain near the 
parent plant, depending on winds (Phillips et al. 2001, p. 11).
    Seeds require no pre-treatment to induce germination, but 
germination success has been shown to improve dramatically when the 
outer seed coat is scarified (e.g., scratched, chipped) (Porter et al. 
2005, p. 29). Germination appears to be more successful in the cooler 
months of the year when temperatures are less than 86 [deg]F (30 
[deg]C) (Romspert and Burk 1979, pp. 45-46). Therefore, based on our 
current understanding of the taxon's life history, sufficient rain in 
conjunction with cool temperatures and wetter-than-average fall weather 
appears to trigger germination events.
    Depending upon conditions, Astragalus magdalenae var. peirsonii is 
capable of flowering before it is one year old (Barneby 1964, p. 862; 
Romspert and Burk 1979, p. 16; Phillips et al. 2001, p. 10; Phillips 
and Kennedy 2005, p. 22). Porter et al. (2005, pp. 31-32) hypothesized 
that if rains occur early in the growing season, then flowering can 
begin in as little as 3 months after germination. If, on the other 
hand, rains (and germination) do not occur until late February, then 
flowering is delayed until the next rainy season. In dry years, 
individuals die and are not replaced by new seedlings.
    This variability in annual abundance of above-ground plants has 
caused this taxon to be considered variously as an annual (completing 
its life cycle in a year or growing season) or a perennial (living for 
more than 2 years) (Munz 1932, p. 7; Munz 1974, p. 432; Barneby 1959, 
p. 879; Barneby 1964, p. 862; Spellenberg 1993, p. 598; Willoughby 
2001, p. 21). Recent evidence has confirmed that this species is a 
short-lived perennial (Phillips et al. 2001, p. 10; Porter et al. 2005, 
pp. 31, 34). This taxon likely depends on the production of seeds in 
wetter years and the persistence of the seed bank from previous years 
to survive until appropriate conditions for germination occur again. 
Porter et al. (2005, p. 29) identified the primary dormancy mechanism 
in Astragalus magdalenae var. peirsonii as the impermeability of the 
seed coat to water and demonstrated little loss of viability in seeds 
stored for 5 years. This dormancy mechanism is consistent with species 
having a seed bank (Given 1994, p. 67). Dispersed seeds in a given year 
that do not germinate during the subsequent growing season become part 
of the soil seed bank (Given 1994, p. 67).

Species Distribution and Abundance

    In the United States, Astragalus magdalenae var. peirsonii is 
restricted to about 53,000 ac (21,500 ha) in a narrow band running 40 
miles (mi) (64 kilometers (km)) northwest to southeast along the 
western portion of the Algodones Dunes of eastern Imperial County, 
California, which is the largest sand dune field in North America. 
Astragalus magdalenae var. peirsonii has also been documented from the 
Gran Desierto of Sonora, Mexico (Felger 2000, p. 300) from an area 
south and southeast of the Sierra Pinacate lava

[[Page 8749]]

field, but the Service has no additional information on the size of the 
population or extent of area occupied (63 FR 53599). The taxon was 
noted from the Borrego Valley, California, by Barneby (1959, p. 879) 
but no verified, reproducing population exists (Porter et al. 2005, pp. 
9-10). Other observations from Yuma, Arizona, and San Felipe, Baja 
California, Mexico, were based on misidentified specimens (see Porter 
et al. 2005, pp. 9-10, and Phillips et al. 2001, p. 7, for detailed 
accounts).
    The Algodones Dunes (Dunes) are one of the largest sand dune fields 
in North America, extending about 40 mi (64 km), trending from 
northwest to southeast (Norris and Norris 1961, p. 608). Please refer 
to the 2003 proposed critical habitat rule for a more detailed 
discussion on the geomorphology of the Dunes (68 FR 46143). These dunes 
are often referred to as the Imperial Sand Dunes, a designation derived 
from their inclusion in the Imperial Sand Dunes Recreation Area (ISDRA) 
established by the Bureau of Land Management (BLM). The majority of the 
Dunes is managed by BLM within 8 management areas, of which 7 are 
occupied by Astragalus magdalenae var. peirsonii (Mammoth Wash, North 
Algodones Wilderness, Glamis, Gecko, Adaptive Management Area (AMA), 
Ogilby, and Buttercup). The State of California and private individuals 
own some small inholdings in the Mammoth Wash management area.
    The ISDRA is the most popular off-highway vehicle (OHV) area in the 
southwest United States, with a specified major focus to ensure that 
OHV recreation opportunities are continuously available while 
responding to increased need for protection of plant and animal species 
in the Dunes (BLM 2003, pp. 1-3). As a result of a settlement agreement 
reached in 2000, the BLM agreed to establish 5 interim closure areas 
within the Dunes, temporarily closing these areas to OHV recreation 
(see Index Map in ``Rule Promulgation'' section). These temporary 
closures are currently still in place.
    The Dunes are in one of the driest and hottest regions in the 
United States. The rainfall is often described as scattered or patchy 
with amounts differing from place to place and from year to year, with 
areas to the northwest being generally dryer than those to the 
southeast (Willoughby 2001, p. 20). Romspert and Burk (1979, p. 11) 
reported average yearly rainfall during the period 1941-1970 was 2.6 in 
(66 millimeters (mm)). Average yearly rainfall between 1997 and 2002 at 
seven weather stations in the vicinity of the Dunes ranged from a low 
of 0.1 in (3.3 mm) during the 2001-2002 growing season to a high of 6.1 
in (155 mm) in the 1997-1998 growing season (Willoughby 2004, p.13). 
Average yearly rainfall between 2002 and 2006 at two weather stations 
on the Dunes ranged from a low of 0.2 in (5.3 mm) during the 2005-2006 
growing season to a high of 4.8 in (122 mm) during the 2004-2005 
growing season (Willoughby 2006, p.18).
    The distribution and abundance of Astragalus magdalenae var. 
peirsonii has been recorded during several ongoing survey efforts. As 
discussed in the 2004 final critical habitat rule (69 FR 47330), the 
1977 dunes-wide survey for A. m. var. peirsonii and four other rare 
psammophytic (sand-loving) scrub species (WESTEC 1977) was considered 
the most extensive survey of the Dunes conducted at that time. The BLM 
conducted rare plant surveys for 5 consecutive years from 1998 through 
2002, generally repeating the methodology used by WESTEC in its 1977 
survey (Willoughby 2001, p. iii). Raw data from the 2001 and 2002 
surveys were provided by the BLM to the Service for use in the 
development of the 2004 final critical habitat rule. However, a written 
report of the 2001 and 2002 surveys (Willoughby 2004) was completed in 
October 2004, after the publication of the August 4, 2004, final 
critical habitat rule. As also discussed in the 2004 final critical 
habitat rule, Phillips and Kennedy (2002, 2003) conducted surveys for 
A. m. var. peirsonii from 2001 through 2003. Since publication of the 
2004 final critical habitat rule, both the BLM (Willoughby 2005a, 
2005b, 2006) and Phillips and Kennedy (2004, 2005, 2006) continued to 
conduct annual surveys for this species through 2006. Table 1 below 
summarizes all of the various survey efforts, including the number of 
sampling points or transects and the effective area surveyed by each 
effort as well as the estimated population by the survey methodology 
and the actual number of plants counted.

       Table 1.--Comparison of Survey Data Collected for Astragalus magdalenae var. peirsonii in the Dunes; Data Taken From 13 Unpublished Reports
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                                                                               Number of plants      Estimated          Number of        Effective area
                    Year                                 Surveyor                  counted           population          samples              *ac)
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1977........................................  WESTEC........................                N/A                N/A              1,611             53,000
1998........................................  BLM \1\.......................              5,064                N/A                542             53,000
1999........................................  BLM \1\.......................                942                N/A                542             53,000
2000........................................  BLM \1\.......................                 86                N/A                542             53,000
2001........................................  BLM \1\.......................              5,930                N/A                542             53,000
2002........................................  BLM \1\.......................              2,297                N/A                542             53,000
2001........................................  Phillips \2\..................         \3\ 71,926                N/A                127           ~ 35,000
2001........................................  Phillips \2\..................             30,771                N/A                 25                138
2003........................................  Phillips \2\..................             33,202                N/A                 25                138
2005........................................  Phillips \2\..................             77,922        \4\ 173,328                 25                138
2006........................................  Phillips \2\..................              1,233          \4\ 2,035                 25                138
2004........................................  BLM \1\.......................             25,798            286,374             37,169             53,000
2005........................................  BLM \1\.......................            739,805          1,831,076            123,488             53,000
2006........................................  BLM \1\.......................                761             83,451                775             53,000
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\1\ BLM reports cited as Willoughby.
\2\ Phillips reports cited as Phillips et al. or Phillips and Kennedy.
\3\ Reconnaissance of unspecified area.
\4\ Estimated population for 60 specific sample sites.

    Since different methodologies and survey effort were used by the 
BLM as compared to Phillips and Kennedy, it is difficult to compare the 
annual estimates of dunes-wide species abundance reported from the two

[[Page 8750]]

different survey efforts. Early surveys conducted by WESTEC in 1977 
(WESTEC 1977) and by BLM from 1998 through 2002 (Willoughby 2001, 2004) 
incorporated a methodology [whereby plants encountered along transects 
were qualitatively indexed to an abundance value] and represented in 
quadrants measuring 0.45 mi (0.72 km) on each side. Analysis of these 
coarse, dune-wide surveys could only provide relative comparisons of 
mean abundance values between years. In 2004, the BLM embarked on a new 
sampling methodology that sampled a larger portion of the Dunes in 
greater detail (Willoughby 2005a, pp. 1-5). Unlike previous surveys, 
the recent BLM surveys were scientifically and statistically designed 
to estimate the standing Astragalus magdalenae var. peirsonii 
population (Willoughby 2005a, 2005b, 2006). Data were compiled in 
adjacent 82 foot x 82 foot (ft) (25 meters x 25 meters (m)) cells along 
2.5-3.1 mi (4-5 km) transects covering the full length of the Dunes, 
and all micro-habitats were sampled along each transect (Willoughby 
2005b, pp. 1-3). Within these 82 ft x 82 ft (25 m x 25 m) cells, 
surveyors noted: The total number of plants; age class of plants; 
number of seedlings; number of flowering versus non-flowering plants; 
number of plants exhibiting damage from OHVs; and the number of plants 
showing damage from other sources (Willoughby 2005b, p. 3). The recent 
BLM surveys also increased the number of sample transects to 135 in 
2004, and to 510 for the spring 2005 surveys (Willoughby 2005b). In 
2006, the BLM used a randomized sample of 2005 known occupied cells 
during the very dry winter and spring of 2006 to yield a population 
estimate for the 2005-2006 survey year (Willoughby 2006, p. 6). Both 
the WESTEC and BLM surveys effectively covered the entire Dunes and 
thus encompassed all management areas containing Astragalus magdalenae 
var. peirsonii (Willoughby 2005a, p. 2).
    By comparison, Phillips et al. (2001, p. 6) counted individual 
Astragalus magdalenae var. peirsonii from 127 specific locations 
covering an unspecified area of about 35,000 ac (14,165 ha) (Phillips 
and Kennedy 2002, Appendix A). Phillips and Kennedy (2002, 2003, 2004, 
2005, 2006) then established 25 monitoring sites from these 127 
locations for their multi-year survey effort, which had an effective 
area of about 138 ac (56 ha).
    The disparity between these three survey methods and the data 
collected makes it difficult to assess status and trends of the 
Astragalus magdalenae var. peirsonii population. However, we consider 
the surveys conducted by BLM to be the most extensive and precise 
effort to determine overall population abundance and distribution for 
this species because this effort effectively covered the entire Dunes 
and thus encompassed all management areas containing Astragalus 
magdalenae var. peirsonii, and because the amount of data gathered in 
2005 was the result of an exceptionally good rainfall year and 
extraordinary monitoring effort. We agree with the BLM that the 2005 
survey effort represents the best estimate to date of distribution and 
abundance of the species on the Dunes (Willoughby 2006, p. v). The 
2005-2006 survey year was an exceptionally dry year, with no A. m. var. 
peirsonii germination reported (Willoughby 2006, p. vi).
    While direct comparison of annual estimates of Astragalus 
magdalenae var. peirsonii abundance reported by BLM and Phillips and 
Kennedy is difficult due to differences in survey methodologies and 
effort used by the surveyors, some comparisons can be made which 
illustrate the wide variation in numbers of standing individuals found 
in any given year and in any given area of the Dunes depending on 
abundance and distribution of rainfall. If we compare BLM data from 
1998 with BLM 2000 data, and compare Phillips and Kennedy's 2001 data 
with their 2003 data, we see the annual variation in species abundance 
at occupied sites. Along the same series of west to east transects, BLM 
counted a total of 5,064 plants in 1998, a heavy rainfall year, and 86 
plants in 2000, a low rainfall year (Willoughby 2004, p. 36). The 
record of steep decline of the cohort counted by Phillips et al. in 
2001 was tracked by Phillips and Kennedy (2002, p. 18), who reported 
that only 26 percent of the plants seen in spring of 2001 were present 
in late 2001. Phillips and Kennedy (2003, p. 12) also reported that 
only 0.26 percent of the plants counted in spring 2001 survived to 
spring 2003.
    This wide variation in numbers of standing individuals is also 
evident when comparing results of the BLM's dunes-wide surveys 
conducted in 2004, 2005, and 2006. In 2004, estimated dunes-wide 
abundance was 286,374 plants (5.5 plants/ac (13.5/ha)) (Willoughby 
2005a, p. 37). In 2005, estimated dunes-wide abundance was 1,831,076 
plants (39.8 plants/ac (86/ha)) (Willoughby 2005b, pp. 9-11). In 2006, 
estimated dunes-wide abundance was 83,451 plants (1.6 plants/ac (3.9/
ha)) (Willoughby 2006, p. vi). Differences in densities (plants per 
acre) are likely due to differences in rainfall between years. An above 
average amount of rainfall was recorded during the 2004-2005 growing 
season, resulting in the greatest abundance of plants to date, while 
the 2005-2006 growing season was considered an exceptionally dry year, 
resulting in zero reported germination. Density in 2004 may have also 
been decreased due to higher average monthly maximum temperatures 
recorded during the survey period, potentially impacting germination 
(Willoughby 2005a, p. 12).
    In any given year, Astragalus magdalenae var. peirsonii may be 
present as standing plants, as a ``soil seed bank'' in the sand dunes, 
or as plants persisting as perennial root crowns in the sand dunes. 
During any given year, the suitable habitat for A. m. var. peirsonii 
may be occupied by various combinations of these three life history 
phases. The dynamics of dune morphology, local rainfall patterns and 
amounts, and the spatial distribution of the soil seed bank contribute 
to the patchy or mosaic nature of the distribution of standing plants 
of A. m. var. peirsonii. As discussed above, local rainfall patterns 
and amounts are likely to cause shifts in the proportions of these 
three life history phases.
    This species was federally listed as threatened due to threats of 
increasing habitat loss from OHV use and associated recreational 
development, destruction of plants, and lack of protection afforded the 
plant under State law (63 FR 53596). Impacts to individual plants and 
their habitat associated with OHV activities and recreation development 
continue to be the primary threat to this species in the United States. 
Please refer to the final listing rule (63 FR 53596) for a detailed 
discussion of the threats to the species and to the ``Special 
Management Considerations or Protection'' section of this final revised 
rule for a more detailed discussion on threats to this species' 
habitat.

Previous Federal Actions

    On August 4, 2004, we published a final rule designating 
approximately 21,863 ac (8,848 ha) of critical habitat for Astragalus 
magdalenae var. peirsonii in Imperial County, California (69 FR 47330). 
Following publication of the final rule, a lawsuit was filed against 
the BLM and the Service alleging, among other violations related to 
protection of A. m. var. peirsonii and desert tortoise (Gopherus 
agassizii), that the Service did not properly consider and weigh the 
benefits and costs associated with designating critical habitat for A. 
m. var. peirsonii. The lawsuit was filed by the Center for Biological 
Diversity, Sierra

[[Page 8751]]

Club, Public Employees for Environmental Responsibility, and Desert 
Survivors (Center for Biological Diversity et al., Plaintiffs v. Bureau 
of Land Management et al., Defendants, and American Sand Association, 
et al., Defendant Intervenors, case 3:03-cv-02509). In a September 25, 
2006, order and injunction regarding final relief, the court ordered 
the Service to submit for publication a new final critical habitat rule 
to the Federal Register no later than February 1, 2008. In addition, 
the Court ordered that the August 4, 2004, final critical habitat 
designation remain in full regulatory force and effect pending 
completion of the new final critical habitat rule for A. m. var. 
peirsonii. When effective, this final revised rule replaces the August 
4, 2004, final critical habitat designation.
    On July 27, 2007 (72 FR 41258), we published a notice in the 
Federal Register announcing: (1) The availability of the proposed rule 
to designate approximately 16,108 ac (6,519 ha) of land within Imperial 
County, California, as revised critical habitat for Astragalus 
magdalenae var. peirsonii; (2) the availability of the draft economic 
analysis (DEA) of the proposed rule to revise critical habitat for 
public review; and (3) the scheduling of public hearings on the 
proposed critical habitat designation and DEA. Public hearings were 
conducted on August 23, 2007, in Carlsbad, California. The public 
comment period closed on September 25, 2007.

Summary of Comments and Recommendations

    We requested written comments from the public on the proposed rule 
to revise critical habitat for Astragalus magdalenae var. peirsonii and 
the associated DEA published on July 27, 2007 (72 FR 41258). During the 
comment period, we requested all interested parties to submit comments 
or information related to the proposed revision to the critical habitat 
designation, including, but not limited to, the following: Unit 
boundaries, species occurrence information and distribution, land use 
designations that may affect critical habitat, potential economic 
effects of the proposed designation, benefits associated with critical 
habitat designation, areas considered but not proposed for designation 
and the associated rationale for the non-inclusion or exclusion of 
these areas, and methods used to designate critical habitat.
    We also contacted appropriate Federal and State agencies, County 
governments, elected officials, and other interested parties through 
telephone calls, letters, and news releases sent by facsimile, U.S. 
mail, or electronic mail, and invited them to comment on the proposed 
revised rule and the associated DEA. We also invited public comment 
through the publication of a notice in the San Diego Union-Tribune. In 
addition, we held two public hearings on August 23, 2007, from 1 p.m. 
to 3 p.m. and from 6 p.m. to 8 p.m. in Carlsbad, California. 
Transcripts of these hearings are available for inspection (see 
ADDRESSES).
    During the comment period that opened on July 27, 2007, and closed 
on September 25, 2007, we received 61 comments directly addressing the 
proposed revised critical habitat designation and the DEA: 3 from peer 
reviewers, 1 from a Federal agency (BLM), and 57 from organizations or 
individuals. We received no comments from State or local agencies.

Peer Review

    In accordance with our policy published on July 1, 1994 (59 FR 
34270), we solicited expert opinions from seven knowledgeable 
individuals with scientific expertise that included familiarity with 
the species, the geographic region in which the species occurs, and 
conservation biology principles. We received responses from three of 
the peer reviewers. The peer reviewers were generally supportive of the 
designation of critical habitat. Most, however, recommended adjusting 
the proposed critical habitat boundaries and altering management 
strategies to provide for better coexistence of OHV recreation and 
Astragalus magdalenae var. peirsonii survival and recovery.
    We reviewed all comments received from the peer reviewers and the 
public for substantive issues and new information regarding critical 
habitat for Astragalus magdalenae var. peirsonii. All comments received 
were grouped into general issue categories relating to the proposed 
rule to revise critical habitat for A. m. var. peirsonii and are 
addressed in the following summary and incorporated into this final 
revised rule as appropriate.

Peer Reviewer Comments

    Comment 1: One peer reviewer suggested the entire Dunes system 
should be designated critical habitat since Astragalus magdalenae var. 
peirsonii grows throughout the dune system.
    Our Response: 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 or 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 describe all areas meeting 
the definition of critical habitat for Astragalus magdalenae var. 
peirsonii. Application of the of the criteria described below (see 
``Criteria Used to Identify Critical Habitat'' section of the proposed 
rule and this final rule) captures areas supporting the physical and 
biological features that are essential to the conservation of the 
species, identified as the primary constituent elements (PCEs) laid out 
in the appropriate quantity and spatial arrangement essential for the 
conservation of the species. Thus, not all areas supporting the 
identified PCEs will meet the definition of critical habitat. We did 
not designate the entire dune system as critical habitat because we do 
not believe that the entire dune system meets the definition of 
critical habitat for Astragalus magdalenae var. peirsonii. Areas 
outside the proposed 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.
    Comment 2: According to one peer reviewer, the most populous site 
in the Dunes in terms of number of plants found during a 2004-05 survey 
was along the International Boundary in the southern portion of Subunit 
4 (Phillips and Kennedy 2005). The third and fourth most populous sites 
were also in this subunit. Because these sites have been systematically 
excluded from BLM surveys, the commenter recommended that a Geographic 
Information System (GIS) specialist should determine if these three 
sites are included in the proposed critical habitat, and if not, adjust 
the boundaries to include them.
    Our Response: After reviewing the GIS data, we have determined that 
the survey sites referenced by Phillips and Kennedy 2005 are within the 
boundaries of the critical habitat designation.
    Comment 3: One reviewer questioned the necessity of including 92 
percent of the Astragalus magdalenae var. peirsonii populations within 
the critical habitat designation to maintain species viability. The 
reviewer further suggested that using a lower percentage of

[[Page 8752]]

captured populations may allow for more intervening areas between 
designated areas of critical habitat, where pass-through routes for 
OHVs could be placed.
    Our Response: Including 92 percent of the Astragalus magdalenae 
var. peirsonii population observed in 2005 was not one of the criteria 
of the proposed critical habitat designation; rather, it was a result 
of applying the methodology outlined in the proposed rule. OHV usage 
patterns were not taken into consideration when proposing revisions to 
critical habitat for A. m. var. peirsonii. The most appropriate 
locations for OHV pass-through routes may be determined by the BLM as 
part of their management plan.
    Comment 4: One reviewer expressed concern that designating all of 
Subunit 3A and the northern portion of Subunit 3B as critical habitat 
could result in greater impacts to Astragalus magdalenae var. peirsonii 
than are now taking place. The reviewer stated that those areas 
received little relative OHV use from 1998 through 2001 (Willoughby 
2001), and predicted the formation of ``sand highways,'' as currently 
observed around existing closure stakes, which may increase disturbance 
if critical habitat designation results in closures to OHV use in those 
areas.
    Our Response: We will work with the BLM to avoid or minimize these 
potential impacts during future section 7 consultations, as 
appropriate, and recommend the BLM take these potential impacts into 
consideration when developing their management plans.
    Comment 5: One peer reviewer stated that according to McGrann et 
al. (2005), moderate to high levels of OHV use can significantly 
decrease the abundance of Astragalus magdalenae var. peirsonii 
seedlings, while low levels of OHV use does not significantly affect A. 
m. var. peirsonii. The reviewer suggested that the entire dune system 
could be opened to OHV use if a management scheme were put in place 
reducing the number of OHV recreationists using the Dunes to low levels 
that would not significantly affect A. m. var. peirsonii.
    Our Response: On Federal land, it is the responsibility of the 
appropriate land management agency to develop and implement resource 
management plans. Comments and suggestions regarding resource 
management in the Dunes should be directed to the BLM. As part of 
developing and implementing a recovery strategy for a listed species, 
we do consider site-specific management strategies important to the 
conservation of the species and we also work with land owners, 
managers, researchers, and others to develop and implement them, as 
appropriate, as part of the recovery process.
    Comment 6: One peer reviewer stated that reproductive success of 
Astragalus magdalenae var. peirsonii is not dependent upon the presence 
of flowering plants between bowls (hollows among the dunes), and that 
no basis was presented in the proposed rule for the assumption that 
areas between bowls are important for maintaining gene flow within the 
population. According to this reviewer, the growing season of 2004 to 
2005 was the first season since 2000 that showed plants growing in any 
quantity on ridges and other features between the bowls that constitute 
the main habitat of A. m. var. peirsonii. The reviewer was concerned 
whether pass-through routes for OHVs could be designated within 
critical habitat in areas that are normally unoccupied without impeding 
gene flow.
    Our Response: The most appropriate locations for OHV pass-through 
routes through designated critical habitat may be determined by the BLM 
as part of their management plan if deemed necessary. We do not concur 
with the reviewer's suggestion that because areas between bowls are not 
consistently occupied by Astragalus magdalenae var. peirsonii plants, 
they may be less important for maintaining gene flow within the 
population. Gene flow is influenced by the movement of pollinators and 
the wind dispersal of fruit and seeds. It is not necessary that 
Astragalus magdalenae var. peirsonii plants be present in an area for 
that area to be important to gene flow.
    Comment 7: One peer reviewer suggested consideration should be 
given to associated habitat and taxa necessary for the accumulation of 
nitrogen-containing compounds when designating critical habitat for 
Astragalus magdalenae var. peirsonii. The presence of detritivores such 
as termites, herbivores, and woody debris, such as that from Croton 
wigginsii and Eriogonum deserticola, should be present in sufficient 
quantities to allow for the continued support of this species in areas 
that have been designated critical habitat when sufficient rainfall is 
available.
    Our Response: The psammophytic scrub plant community that supports 
detritivores and other biota, of which Astragalus magdalenae var. 
peirsonii is a component, is included as a PCE in the rule. The need to 
preserve this community was considered in our analysis. While we did 
not specifically analyze the role detritivores play in providing 
mineral resources to A. m. var. peirsonii, we believe that the 
associated psammophytic scrub plant community within designated 
critical habitat should support detritivores in sufficient quantities 
to provide the necessary mineral resources for A. m. var. peirsonii.
    Comment 8: One peer reviewer pointed out that given the constant 
shifting of the Dunes, the Dunes are relatively non-static; therefore, 
critical habitat designated in 2007 may not be as viable in 2015 
because the depth of available Astragalus magdalenae var. peirsonii 
seed and the aspect of bowls may change over time. The reviewer 
suggested that we allow for the dynamic nature of the dune landscape by 
designating critical habitat units that are ``oriented slightly NW to 
SE from proposed positions'' in some instances.
    Our Response: Astragalus magdalenae var. peirsonii is adapted to 
the non-static nature of the Dunes. If the aspect of bowls changes over 
time without changing geographic position, they likely would remain 
within critical habitat. Critical habitat can also be revised if new 
information indicates changes in the distribution of essential features 
have occurred (this current rule is such a revision).
    Comment 9: One peer reviewer commented that Phillips and Kennedy 
(2005) documented plants germinating and flowering in the first growing 
season twice over the past seven years. The reviewer suggested we cite 
this data-based conclusion rather than the Porter et al. (2005) 
hypothesis on page 41259 of the proposed rule (72 FR 41258: July 27, 
2007).
    Our Response: Phillips and Kennedy (2005) were cited in the 
proposed critical habitat (see 72 FR 41259, third column, second full 
paragraph, first sentence). We believe that both citations are 
relevant.
    Comment 10: One reviewer noted that reference to the existence of a 
seed bank for Astragalus magdalenae var. peirsonii is made on numerous 
occasions in the proposed rule, but Phillips and Kennedy's (2002, 2006) 
two reports detailing studies of the seed bank are not cited. The 
reviewer suggested that these reports either be acknowledged, or a 
reason presented for their exclusion.
    Our Response: Although the two studies in question do provide 
valuable information regarding the seed bank of Astragalus magdalenae 
var. peirsonii, we determined that it was not appropriate to cite 
either study in relation to the specific statements referenced in the 
rule.
    Comment 11: One reviewer recommended that the Service form an

[[Page 8753]]

advisory committee comprised of representatives from affected agencies 
and advocacy groups with the goal of developing a critical habitat 
designation.
    Our Response: Through our rulemaking process, we have solicited 
input from affected agencies and advocacy groups via our request for 
comments on the proposed critical habitat designation and during the 
public hearings. All comments received have been considered and 
incorporated into the final critical habitat rule as appropriate. 
Therefore, we believe we have appropriately sought and considered the 
opinions of all interested parties during the promulgation of this 
revised rule.
    Comment 12: All three peer reviewers offered recommendations 
intended to improve management of the Dunes to allow coexistence of 
Astragalus magdalenae var. peirsonii and OHV use in coordination with 
the critical habitat designation, or to alter the proposed critical 
habitat designation based on dune management considerations.
    Our Response: On Federal land, it is the responsibility of the 
appropriate land management agency to develop and implement resource 
management plans. Comments and suggestions regarding resource 
management in the Dunes should be directed to the BLM. As part of 
developing and implementing a recovery strategy for a listed species, 
we do consider site-specific management strategies important to the 
conservation of the species and work with landowners, managers, 
researchers, and others to develop and implement such strategies, as 
appropriate, as part of the recovery process.

Public Comments

    Comment 13: A number of commenters asserted that scientific 
evidence supports the hypothesis that OHV activity does not harm 
Astragalus magdalenae var. peirsonii populations. Some commenters cited 
personal observations that the habitat has changed little during their 
history of visitation and that OHV users deliberately avoid A. m. var. 
peirsonii because of damage to tires.
    Our Response: The commenters did not provide any additional 
scientific information or data to support the hypothesis that OHV 
activity does not harm Astragalus magdalenae var. peirsonii 
populations. The best scientific information suggests that OHV use can 
damage A. m. var. peirsonii habitat (Groom et al. 2007). Groom et al. 
(2007, p.132) demonstrated that OHV impact reduced the survival of 
small A. m. var. peirsonii individuals by 33 percent over a 3 month 
period. Further, this study indicated that within the Dunes, areas open 
to OHV use supported 4 to 5 times fewer plants than areas closed to OHV 
use (Groom et al. 2007, p. 130). However, in the relatively short time 
frame that A. m. var. peirsonii has been monitored, populations of the 
plant appear to persist in areas of OHV use, perhaps because OHV users 
tend to avoid A. m. var. peirsonii as asserted by the commenter. 
Further monitoring may show whether this persistence will continue over 
time and which factors, including avoidance, influence A. m. var. 
peirsonii persistence.
    Comment 14: One commenter asserted the proposed revised rule did 
not include all the best available science. Specifically the commenter 
asserted the proposed revised rule did not: (1) Incorporate data from 
monitoring other than those collected during 2004-2005; in particular 
no data was considered from the highest precipitation season (1997-
1998); (2) take into consideration that more conservative design and 
implementation of conservation plans are required for species whose 
numbers are not stable (cited Noss et al. 1997); (3) take into 
consideration the hypothesis that genetically similar plants may not be 
able to produce viable seeds, and therefore populations must maintain a 
``large number of individuals'' (cited Porter et al. 2005); and (4) 
take into consideration the transient or shifting nature of Astragalus 
magdalenae var. peirsonii habitat distribution. The commenter asserted 
the Dunes are documented to migrate in a southeasterly direction 16 to 
66 ft (5 to 20 m) per year (cited Porter et al. 2005); therefore, the 
proposed critical habitat may not include the primary constituent 
elements (PCEs) in 100 years.
    Our Response: Regarding the commenter's first assertion, we did 
take into consideration the 1998 data, but found the 2004 to 2005 data 
to be more appropriate for use in our critical habitat model. For 
example, the 2005 study more intensively sampled areas found to be 
occupied in the 1998 study, and distribution information had a finer 
geographic resolution (provided more spatial detail). Also, average 
annual rainfall during both sample seasons was approximately double the 
annual average in the ISDRA (which includes approximately 167,000 ac 
(67,582.50 ha) of the Dunes), and when data from all 1997-2005 surveys 
are overlaid on proposed revisions to critical habitat, all higher 
density distribution areas within sample sites appear to be captured. 
It is not likely that final revisions to critical habitat would have 
been altered by inclusion of data from years other than 2005. In the 
proposed revision to critical habitat (72 FR 41258; July 27, 2007), we 
cited Willoughby's 2001 report with 1997 to 1998 survey data 5 times; 
in the background section regarding variability in annual abundance of 
above-ground plants, rainfall variability, and data availability, we 
specifically stated that this information was considered in our 
methodology. Regarding the commenter's second assertion, although we do 
consider conservation and recovery standards when designing critical 
habitat, critical habitat is not a conservation plan. The design and 
implementation of conservation initiatives will be addressed by those 
charged with management of Dunes lands (e.g., the BLM). Regarding the 
commenter's third assertion, although Porter et al. (2005) did conclude 
that a ``large number of individuals'' must be maintained because of 
the need for high genetic diversity at the self-incompatibility loci 
(location of genes on the DNA strand), he did not give any quantitative 
estimate of what was meant by ``large.'' Porter also concluded that the 
number of individuals present in the ISDRA is ``quite high,'' and the 
number of individuals is not as important as the genetic diversity of 
individuals present. No information provided by Porter (2005) indicates 
that areas not included in proposed revisions to critical habitat (72 
FR 41258; July 27, 2007) contain individuals with higher genetic 
diversity, or that densities we used as criteria for including areas in 
the critical habitat designation were too low. Regarding the 
commenter's fourth assertion, future recovery plans, habitat 
conservation plans, or other species conservation planning efforts will 
take into consideration changes in the distribution of essential 
features, if new information indicates such changes have occurred. 
Critical habitat can also be revised if new information indicates 
changes in the distribution of critical habitat have occurred (this 
current rule is such a revision). We do not believe it is prudent to 
predict dune position 100 years into the future, especially considering 
changes in temperatures, precipitation amounts, wind patterns, and 
extreme weather, including droughts, heavy precipitation, and climate 
change predicted globally (IPCC 2007, pp. 8-9) and in southern 
California (Field et al. p. 52; Seager et al. 2007, p. 1181).
    Comment 15: One commenter alleged the proposed revised rule is 
flawed because it does not include all occupied habitat, and does not 
include any unoccupied habitat. Specifically: (1) No

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scientific justification was given for the use of 100 plants per 2.5-ac 
(1-ha) density as a criterion for inclusion; (2) the 328 ft (100 m) 
distance between 2.5 ac (1 ha) core areas does not take into 
consideration the distance Astragalus magdalenae var. peirsonii 
inflated seedpods can disperse; (3) the area required to assure species 
persistence and recovery depends on numerous other attributes besides 
density (cited Burgman et al. 2001); and (4) recent science indicates 
occupied habitat containing populations on the periphery of the range 
of the species is essential to long-term species survival, especially 
with regard to preservation of local genetic diversity (cited Leppig 
and White 2006, Gapare et al. 2005, Channell and Lomolino 2000, Lammi 
et al. 1999) and global climate change (cited Safriel et al. 1994).
    Our Response: Regarding the commenter's first statement, we are not 
aware of any published scientific information providing quantified 
density requirements for this species, and no such information was 
provided by the commenter. As discussed in the ``Summary of Changes 
from the Previously Designated Critical Habitat and 2007 Proposed 
Revised Rule'' section below, the reference to 100 plants/ha was an 
error in the proposed rule, and the actual density used was 480 plants/
ha. Since no established density criteria exist for Astragalus 
magdalenae var. peirsonii, we chose the 480 plants/ha based on the 
qualitative observation that it captured the majority of large clusters 
of standing plants and the belief that these densities are likely to be 
correlated with high-quality habitat characteristics (e.g., suitable 
dune morphology, soil moisture) and high-density seed banks. We also 
note that this density only applied to cells selected in the first 
criterion as a starting point for inclusion, and was not exclusive of 
adjacent, potentially lower density areas. We subsequently expanded 
each cell to a size 16 times greater. The first criterion captured 
approximately half of the 2005 observed population, while after all 
subsequent criteria were applied, approximately 92 percent had been 
captured.
    Regarding the commenter's second statement, we agree the potential 
distance seeds can be dispersed is greater than 328 ft (100 m); 
however, we aggregated the 2.5-ac (1-ha) core areas within 328 ft (100 
m) of each other to maintain unoccupied space for wind dispersal of 
seeds between occupied dune bowls. This 328 ft (100 m) distance is a 
Dunes-wide approximation of the average distance between aggregated 
core areas.
    Regarding specific comments 3 and 4, these comments, and all 
scientific papers cited by the commenter, are based on the density or 
importance of distinct biological populations on the periphery of a 
species' range and do not apply to Astragalus magdalenae var. peirsonii 
in the context of this rule. The entire range of A. m. var. peirsonii 
within the ISDRA appears to function as a single population with a 
semi-continuous distribution (includes movement areas, a semi-
continuous distribution of standing plants) composed of spatially 
clustered, but not isolated, ``colonies'' (Porter 2005, p. 14, 21). 
Even colonies not connected by habitat for adult growth (for example, 
separated by a highway) would not be independent biological populations 
unless the non-growth habitat area significantly reduced genetic 
exchange among colonies. Although Porter (2005, p. 17) sampled 30 
``populations,'' the word population in that context refers to 
statistical, not biological, populations.
    Comment 16: One commenter asserted that the proposed rule is flawed 
because it fails to address all primary constituent elements (PCEs). 
Specifically: (1) Habitat for the white-faced digger bee (Habropoda 
pallida, the most common pollinator), the digger wasp, or the European 
honeybee should have been included, because pollination is required in 
order for Astragalus magdalenae var. peirsonii to set viable seeds 
(cited Porter 2005); and (2) by removing core areas over 1,312 ft (400 
m) from higher density core areas, the proposal fails to include areas 
containing the PCE ``intervening areas for gene flow and connectivity 
within the population.'' The commenter asserted that basic conservation 
biology principles dictate the need for large connected areas of 
habitat that support essential ecological functions such as pollinator 
habitat and seed dispersal (cited Noss et al. 1997). The commenter 
stated that although data on forage distances for native pollinators 
are not available, studies of other solitary bees found a foraging 
distance ranged from 492 to 1,969 ft (150 to 600 m) (cited Gathmann and 
Tscharntke 2002) and the median foraging range of the European honeybee 
is 3.8 mi (6.1 km) (cited Beekman and Ratnieks 2000).
    Our Response: Primary constituent element number 2 as defined in 
the proposed revised rule states that habitat for insect pollinators, 
particularly the white-faced digger bee, is required for reproduction 
of Astragalus magdalenae var. peirsonii, and we believe the proposed 
revised critical habitat incorporates sufficient habitat to support 
these pollinator species. The information regarding pollinator movement 
distances appears to suggest that all areas within those distances from 
an occurrence of A. m. var. peirsonii should be included in critical 
habitat. We considered this approach, but concluded that doing so would 
include large areas of unoccupied habitat that are not essential to the 
conservation of A. m. var. peirsonii, because based on the best 
scientific information available to us, sufficient habitat exists to 
support pollinators within the designated critical habitat units. We 
agree that basic conservation biology principles support the value of 
connected areas of habitat of suitable size for supporting essential 
ecological functions such as pollinator habitat and seed dispersal. We 
believe this final revised critical habitat designation constitutes 
sufficient areas of connected habitat to support seed dispersal and 
pollination, and therefore does not violate basic conservation biology 
principles.
    Comment 17: One commenter expressed the belief that the Service's 
biological methodology was sound and the criteria were appropriate. 
They stated the 16,106 ac (6,518 ha) of proposed critical habitat is 
``more than adequate'' to protect Astragalus magdalenae var. peirsonii 
and ensure species' recovery.
    Our Response: We appreciate the comment in support of this revised 
designation of critical habitat for Astragalus magdalenae var. 
peirsonii.
    Comment 18: One commenter expressed the opinion that recreational 
use does not appear to negatively affect pollination of Astragalus 
magdalenae var. peirsonii by white-faced digger bees.
    Our Response: Please see response to comment 13 above. Because the 
commenter did not provide any additional information or data to support 
their opinion, we were unable to consider the validity of the claim.

Comments Related to Legal and Procedural Issues

    Comment 19: A number of commenters expressed concern regarding 
continued or additional closures of dune areas to OHV activity. In some 
cases it appeared they believed critical habitat designation was 
equivalent to closure, in other cases the designation would mandate 
additional or expanded closures, and in a few cases commenters were 
apparently confused regarding the reason for existing closures.
    Our Response: Current closures in the ISDRA are not a result of 
critical habitat designation; they are a result of legal

[[Page 8755]]

proceedings and administrative actions taken by the BLM that pre-date 
the current critical habitat designation (69 FR 47330; August 4, 2004). 
Critical habitat designation does not establish a refuge, wilderness 
reserve, preserve, or other conservation area. If a project that 
requires Federal funding, permitting, or authorization (such as 
management actions by the BLM) is planned in designated critical 
habitat, and the Federal agency (such as BLM) determines the project 
may affect Astragalus magdalenae var. peirsonii or its critical 
habitat, the agency responsible for providing the funding or permit is 
required, in consultation with the Service, to ensure that the project 
will not jeopardize the continued existence of the species or adversely 
modify critical habitat. We assume that BLM will take the critical 
habitat designation into consideration during their revised ISDRA 
planning process, as well as other relevant factors. Areas within a 
critical habitat designation, particularly occupied areas (all in this 
case), are already subject to regulatory protections afforded by the 
section 7(a)(2) jeopardy standard of the Act.
    Comment 20: A number of commenters suggested management strategies 
to reduce the threat of OHV impacts to Astragalus magdalenae var. 
peirsonii.
    Our Response: Please see response to comment 5.
    Comment 21: One commenter asserted that because the proposed 
critical habitat did not include all recently occupied habitats, it 
does not meet the recovery standard of critical habitat designation. 
The commenter asserted that species recovery standards must be met by 
critical habitat designations, not just species extinction thresholds 
needed to meet the jeopardy standard.
    Our Response: Please see response to comment 1. We do not concur 
with the commenter's assertion that all recently occupied habitats need 
to be designated as critical habitat in order to achieve recovery of 
the species.
    Comment 22: One commenter stated they were opposed to any 
exclusions of essential habitat based on coverage by management plans. 
They stated that all essential habitat needs special management because 
it is subject to impacts from motorized vehicle recreation, even in 
wilderness areas where closure violations occur, and the District Court 
in Arizona found that existence of a management plan is proof that an 
area qualifies as critical habitat (cited Center for Biological 
Diversity, et al. v. Norton, 240 F. Supp. 2d 1090, 1099).
    Our Response: No exclusions based on management plans were proposed 
or made in this final rule.

Comments From Other Federal Agencies

    Comment 23: One commenter stated that Fall weather does not have to 
be wetter than average to trigger germination; all that is required is 
a single rainfall event sufficient to induce germination (approximately 
1 in (2.5 cm)), so Fall rainfall could still be below the Fall average. 
The commenter recommended we alter the assertion in 72 FR 41259, column 
3, paragraph 2, last sentence (``* * * based on our current 
understanding of the taxon's life history, sufficient rain in 
conjunction with cool temperatures and wetter-than-average Fall weather 
appears to trigger germination events'') to reflect this point in the 
final rule.
    Our Response: By ``germination event,'' we meant germination of a 
large number of Astragalus magdalenae var. peirsonii seeds at the same 
time. Thus, the statement in the proposed revised critical habitat rule 
is correct. While it may not require wetter-than-average Fall weather 
to trigger germination of some Astragalus magdalenae var. peirsonii 
seeds, wetter-than-average Fall weather is likely necessary to produce 
a mass germination event.
    Comment 24: One commenter stated that there is no evidence that 
wind-driven sand provides the primary mechanism for seed scarification. 
The commenter stated that seeds usually have their hard seed coats 
rendered permeable by high summer temperatures or fire. In citing 
Baskin and Baskin (1989) as support for this statement, the commenter 
recommended we alter the statement in 72 FR 41263, column 3, paragraph 
3, sentence 1 of the proposed revised rule to reflect this point in the 
final rule.
    Our Response: It has been shown that wind-driven sand does scarify 
Astragalus magdalenae var. peirsonii seeds (Porter et al. 2005, p. 29); 
however, heat may be a contributing factor as well. We will consider 
this information in future management recommendations.
    Comment 25: One commenter requested that we clarify the use of the 
word ``higher'' on 72 FR 41268 of the proposed rule which reads, 
``Habitat within these subunits [Subunits 1A and 1B in the Mammoth Wash 
management area] contains a higher density of standing plants and is 
likely to support a large seed bank based on our analysis of BLM's 2004 
survey data in addition to containing the PCEs required by the 
species.''
    Our Response: We clarified this statement in this final rule to 
indicate that the habitat within Subunits 1A and 1B contained a higher 
density of standing Astragalus magdalenae var. peirsonii plants than 
areas adjacent to and outside of Subunits 1A and 1B based on our 
analysis of BLM's 2005 survey data.

Comments Related to the Draft Economic Analysis

Geographic Scope of Analysis

    Comment 26: Several commenters believe that the Draft Economic 
Analysis (DEA) underestimates impacts because it fails to consider 
impacts outside of Imperial and Yuma Counties. Commenters noted that 
most visitors to the ISDRA do not come from the local area. Another 
commenter asserted that the DEA overstates regional economic impacts 
because there is no evidence that people visiting the ISDRA are 
purchasing their groceries or a significant portion of their ORV 
equipment and supplies in Imperial or Yuma County.
    One commenter also provided additional information on the 
geographic and economic scope of the sand-recreation industry. 
Specifically, the commenter provided a summary by location of 488 
advertisers that support the American Sand Association to demonstrate 
that only a small proportion of these businesses and associations are 
located in Imperial and Yuma Counties. This commenter also provided 
anecdotal evidence to support the fact that businesses outside of 
Imperial and Yuma Counties are likely to be affected by the proposed 
critical habitat. This commenter also noted that there are ``practical 
and sound theoretical reasons'' for limiting the geographic scope of 
the regional economic analysis to Imperial and Yuma Counties.
    Our Response: In the DEA, as in the 2004 Economic Analysis, the 
focus of the analysis is on the two counties that are expected to bear 
the greatest impact of any reduced visitation by OHV enthusiasts to the 
ISDRA, relative to overall economic activity in these counties (see 
Section 3.3.2 of the DEA). Thus, any change in sales resulting from 
changes in ISDRA visitation would be expected to have a 
disproportionate effect on these economies. This study area was chosen 
based on information in the 2003 Final Environmental Impact Study 
(FEIS) of the BLM's Recreation Area Management Plan (RAMP) and 
discussion with the American Sand Association (ASA), Imperial County 
Board of Supervisors, and the Brawley

[[Page 8756]]

Chamber of Commerce. Additional text related to this issue has been 
added to the Final Economic Analysis (FEA) in Section 3.3.3.

Expenditure Estimates

    Comment 27: Several commenters believe the per-vehicle trip 
expenditure estimate is understated because it does not include 
equipment purchases. Various commenters believe that the DEA failed to 
account for investment in high-value dune recreation equipment and 
specialty parts. Several commenters stated that if additional 
restrictions are imposed on duning activity as a result of the proposed 
critical habitat, this equipment will lose its value and no 
reinvestment in such assets will occur. One commenter asserted that the 
potential loss of revenue for the sheet metal fabrication industry will 
go into the billions of dollars, and two commenters provided 
information regarding the 2006 Sand Sports Super Show as support for 
the magnitude of the industry likely to be affected.
    Our Response: Potential impacts on OHV sales are difficult to 
assess, as no data exist to model where OHV enthusiasts from the 
greater California and Arizona region purchase vehicles and other 
equipment, or how these purchases will change in response to reduced 
access within the ISDRA. As discussed in Section 3.3.2 of the DEA, 
given this uncertainty, the analysis applies a range of estimated 
average per-vehicle trip expenditures. The estimated range of 
expenditures ($279-$544 in 2007 dollars) represents average 
expenditures within the study area, and incorporates information from 
OHV user groups, including the ASA and the Off Road Business 
Association (OBRA).
    The analysis recognizes the possibility that capital expenditures 
on OHV equipment could be impacted by limitations on OHV activity 
within the ISDRA. As shown in Exhibit 3-6 of the DEA, a portion (36 
percent to 38 percent) of the expenditures per vehicle trip falls into 
the category of ``OHV Equipment Supplies and Services.'' The 
apportionment of the estimated expenditures per vehicle trip was based 
on a survey of OHV users conducted for the California Department of 
State Parks and Recreation (CADSPR). In a recent survey of ISDRA 
visitors (Haas/Collins 2006), respondents indicated that approximately 
21 percent of expenditures were for ``Vehicle Maintenance and Repair.'' 
Although this figure is somewhat lower than the 36 to 38 percent 
applied in the DEA, the Haas/Collins expenditure category excludes 
expenditures on ``OHV equipment supplies.'' While overall cost 
estimates within the report remain unchanged, Section 3.2 of the FEA 
has been revised to provide additional information on investment in OHV 
equipment.
    Comment 28: Various commenters provided information on what they 
consider ``average'' per trip expenditures ranging from $350-$450. One 
commenter stated his group represents about $1 million per year at the 
ISDRA, not including travel and food. Another commenter states Exhibit 
3-6 on page 3-16 of the DEA underestimates the cost of fuel per trip.
    Our Response: As discussed in Section 3.3.2, the DEA was based on 
the best available information on expenditures by visitors to the 
ISDRA. The estimated range of expenditures per vehicle trip to the 
ISDRA ($279-$544 in 2007 dollars) represents average expenditures 
within the study area (defined as Imperial and Yuma Counties), based on 
information from OHV user groups, including the ASA and OBRA. The per-
trip expenditure information provided in public comment falls within 
the range of expenditures estimated in the DEA. As explained in Exhibit 
3-6, O