Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Callippe Silverspot Butterfly and the Behren's Silverspot Butterfly and Threatened Status for the Alameda Whipsnake

Summary

The Fish and Wildlife Service (Service) determines endangered status pursuant to the Endangered Species Act of 1973, as amended (Act) for the callippe silverspot butterfly (Speyeria callippe callippe) and Behren's silverspot butterfly (Speyeria zerene behrensii) and threatened status for the Alameda whipsnake (Alameda striped racer) (Masticophis lateralis euryxanthus). The callippe silverspot butterfly is found at two sites on grasslands in the San Francisco Bay area. Behren's silverspot butterfly is found within coastal terrace prairie at one site in southern Mendocino County. These butterflies are imperiled by overcollecting, urban development, alien plant invasion and competition, and excessive livestock grazing. The Alameda whipsnake occurs in the northern coastal scrub and chaparral habitats of Contra Costa and Alameda counties. This snake and its associated habitat are threatened by fire suppression and related wildfire problems associated with lack of fuel reduction, urban development, genetic isolation, and excessive livestock grazing. This rule implements Federal protection and recovery provisions afforded by the Act for these animals.

Full text

SUMMARY: The Fish and Wildlife Service (Service) determines endangered 
status pursuant to the Endangered Species Act of 1973, as amended (Act) 
for the callippe silverspot butterfly (Speyeria callippe callippe) and 
Behren's silverspot butterfly (Speyeria zerene behrensii) and 
threatened status for the Alameda whipsnake (Alameda striped racer) 
(Masticophis lateralis euryxanthus). The callippe silverspot butterfly 
is found at two sites on grasslands in the San Francisco Bay area. Behren's silverspot butterfly is found within coastal terrace 
prairie at one site in southern Mendocino County. These butterflies are 
imperiled by overcollecting, urban development, alien plant invasion 
and competition, and excessive livestock grazing. The Alameda whipsnake 
occurs in the northern coastal scrub and chaparral habitats of Contra 
Costa and Alameda counties. This snake and its associated habitat are 
threatened by fire suppression and related wildfire problems associated 
with lack of fuel reduction, urban development, genetic isolation, and 
excessive livestock grazing. This rule implements Federal protection 
and recovery provisions afforded by the Act for these animals.

DATES: Effective December 5, 1997.

ADDRESSES: The complete file for this rule is available for public 
inspection, by appointment, during normal business hours, at the 
Sacramento Field Office, U.S. Fish and Wildlife Service, 3310 El Camino 
Ave., Suite 130, Sacramento, California 95821.

FOR FURTHER INFORMATION CONTACT: Mike Westphal or Diane Windham, staff 
biologists, at the above address or by telephone (916/979-2725).

SUPPLEMENTARY INFORMATION:

Background

    The callippe silverspot butterfly (Speyeria callippe) is a member 
of the brush foot family (Nymphalidae). The animal was described by 
J.A. Boisduval (1852) from specimens collected during the month of June 
by Pierre Lorquin in San Francisco, California (dos Passos and Grey 
1947). It is a medium sized butterfly with a wingspan of approximately 
5.5 centimeters (cm) (2.2 inches (in)). The upper wings are brown with 
extensive black spots and lines, and the basal areas are extremely 
melanic (dark-colored). Wing undersides are brown, orange-brown, and 
tan with black lines and distinctive black and bright silver spots. 
Basal areas of the wings and body are densely pubescent (hairy).
    The discal area on the upper hind wings of the callippe silverspot 
butterfly is a darker, more extensive yellow than on the related 
Lilian's silverspot butterfly (Speyeria callippe liliana). The callippe 
silverspot butterfly is larger and has a darker ground color with more 
melanic areas on the basal areas of the wings than Comstock's 
silverspot butterfly (Speyeria callippe comstocki), another related 
taxon.
    The callippe silverspot butterfly is found in native grassland and 
associated habitats (Thomas Reid Associates 1982; Steiner 1990; 
Mattoon, in litt., November 22, 1992). The females lay their eggs on 
the dry remains of the larvae foodplant, Johnny jump-up (Viola 
pedunculata), or on the surrounding debris (Arnold 1981, Thomas Reid 
Associates 1982). Within about 1 week of hatching the larvae eat their 
egg shells. The caterpillars wander a short distance and spin a silk 
pad upon which they pass the summer and winter. The larvae are dark 
colored with many branching sharp spines on their backs.
    The caterpillars immediately seek out the foodplant upon 
termination of their diapause in the spring. In May, after having gone 
through five instars, each larva forms a pupa within a chamber of 
leaves drawn together with silk. Adults emerge in about 2 weeks and 
live for approximately 3 weeks. Depending upon environmental 
conditions, the flight period of this single-brooded butterfly ranges 
from mid-May to late July. The adults exhibit hilltopping behavior, a 
phenomenon in which males and virgin or multiple-mated females seek a 
topographic summit on which to mate (Shields 1967).
    Arnold (1983, 1985) conducted taxonomic studies on the subspecies 
of Speyeria callippe using wing characters. He concluded that the 
species consisted of 3 subspecies rather than the widely recognized and 
accepted 16 subspecies. Based on his study, the range of Speyeria 
callippe callippe would extend from Oregon to southern California and 
east into the Great Basin (Arnold 1985). A comprehensive analysis of 
this species found that the original classification remains more 
appropriate and that subspecies callippe is restricted to the San 
Francisco Bay region (Hammond 1986; Murphy undated). The Service 
recognizes the conclusions of Hammond (1986) and the distribution of 
the callippe silverspot butterfly as described by Sterling Mattoon (S. 
Mattoon, in litt., November 22, 1992).
    The callippe silverspot butterfly is known from 14 historic 
populations in the San Francisco Bay region. The historic range of the 
callippe silverspot butterfly includes the inner Coast Ranges on the 
eastern shore of San Francisco Bay from northwestern Contra Costa 
County south to the Castro Valley area in Alameda County (S. Mattoon, 
in litt., November 22, 1992). On the west side of the Bay, it ranged 
from San Francisco south to the vicinity of La Honda in San Mateo 
County. Five colonies, including the one located at Twin Peaks in San 
Francisco have been extirpated for a variety of reasons. Currently, 
extant colonies are known only from private land on San Bruno Mountain 
in San Mateo County, and a city park in Alameda County (S. Mattoon, in 
litt., November 22, 1992).
    Behren's silverspot butterfly (Speyeria zerene behrensii) is also a 
member of the brush foot family (Nymphalidae). William H. Edwards 
described this taxon in 1869 based on an adult male collected by an 
unknown lepidopterist in Mendocino, California (Edwards 1869, dos 
Passos and Grey 1947). It is a medium-sized butterfly with a wingspan 
of approximately 5.5 cm (2.2 in). The upper surfaces are golden brown 
with numerous black spots and lines. Wing undersides are brown, orange-
brown, and tan with black lines and distinctive silver and black spots. 
Basal areas of the wings and body are densely pubescent.
    Behren's silverspot butterfly is similar in appearance to two other 
subspecies of Speyeria zerene (Howe 1975, Hammond 1980, McCorkle and 
Hammond 1988). The Oregon silverspot butterfly (Speyeria zerene 
hippolyta), federally listed as threatened, has lighter basal suffusion 
on the upper sides of the wings than Behren's silverspot butterfly. 
Another related taxon, the endangered Myrtle's silverspot butterfly 
(Speyeria zerene myrtleae) is larger in size and also lighter in color 
than Speyeria zerene behrensii.
    Behren's silverspot butterfly inhabits coastal terrace prairie 
habitat. The life history of Behren's silverspot butterfly is similar 
to the callippe silverspot butterfly. The females lay their eggs in the 
debris and dried stems of the larval foodplant, violet (Viola adunca) 
(McCorkle 1980, McCorkle and Hammond 1988). Upon hatching, the 
caterpillars wander a short distance and spin a silk pad upon which 
they pass the fall and winter. The larvae are dark-colored with many 
branching, sharp spines on their backs. The caterpillars immediately 
seek out the foodplant upon termination of their diapause in the 
spring. They pass through five instars before forming a pupa within a 
chamber of leaves that they draw together with silk. The adults emerge 
in about 2 weeks and live for approximately 3 weeks. Depending upon 
environmental conditions, the flight period of this single-brooded 
butterfly ranges from July to August. Adult males patrol open areas in 
search of newly emerged females.
    The historic range of Behren's silverspot butterfly extends from 
the mouth of the Russian River in Sonoma County northward along the 
immediate coast to southern Mendocino County in the vicinity of Point 
Arena (S. Mattoon, in litt., August 4, 1989). Six historic populations 
are known from coastal terrace prairie and associated habitats. The single extant population is located on private land near Point 
Arena in Mendocino County.
    The Alameda whipsnake (Alameda striped racer) (Masticophis 
lateralis euryxanthus) is a member of the family Colubridae (Stebbins 
1985). It was described by William J. Riemer (1954) from a total of six 
specimens collected in the vicinity of Berkeley, Alameda County, and 
near Somersville, Contra Costa County, and from Mount Diablo, Contra 
Costa County, California. The Alameda whipsnake is a slender, fast-
moving, diurnal snake with a narrow neck and a relatively broad head 
with large eyes. The dorsal surface is colored sooty black with a 
distinct yellow-orange stripe down each side. The anterior portion of 
the ventral surface is orange-rufous colored, the midsection is cream 
colored, and the posterior and tail are pinkish. Adults range in length 
from 91 to 122 cm (3 to 4 feet (ft)).
    The Alameda whipsnake inhabits the inner Coast Ranges in western 
and central Contra Costa and Alameda counties (Jennings 1983, McGinnis 
1992, Swaim 1994). Urban development has fragmented the originally 
continuous range of the whipsnake into five populations centered in the 
(1) Sobrante Ridge, Tilden/Wildcat Regional Parks area to the Briones 
Hills, in Contra Costa County (Tilden-Briones population); (2) Oakland 
Hills, Anthony Chabot area to Las Trampas Ridge, in Contra Costa County 
(Oakland-Las Trampas population); (3) Hayward Hills, Palomares area to 
Pleasanton Ridge, in Alameda County (Hayward-Pleasanton Ridge 
population); (4) Mount Diablo vicinity and the Black Hills, in Contra 
Costa County (Mount Diablo-Black Hills population); and (5) Wauhab 
Ridge, Del Valle area to the Cedar Mountain Ridge, in Alameda County 
(Sunol-Cedar Mountain population). These populations all occur on 
private or public, non-Federal, land.
    Due to the fragmentation of the range of the Alameda whipsnake, 
little or no interchange occurs among the five populations. The ability 
of the whipsnake to interchange among the first three populations 
described above is contingent on their dispersing over the Caldecott 
Tunnel in Contra Costa County and under Highway 580 in Alameda County 
at the Eden Canyon interchange, the Dublin Boulevard undercrossing, or 
where San Lorenzo Creek passes under the highway. The ability of the 
Alameda whipsnake to interchange between the Hayward-Pleasanton Ridge 
and Sunol-Cedar Mountain populations depends on their dispersing along 
Alameda Creek in Alameda County and crossing under Highway 680 where 
the creek passes under the highway, or crossing under the highway at 
Scott's Corner along Vallecitos Creek, or where two unnamed tributaries 
to Arroyo de la Laguna cross under Highway 680 north of Scott's Corner. 
The Mount Diablo-Black Hills population has no path for dispersal to 
any of the other populations.
    The Alameda whipsnake is distinguished from the chaparral whipsnake 
(Masticophis lateralis lateralis) by its sooty black dorsum, by wider 
yellow-orange stripes that run laterally down each side, the lack of a 
dark line across the rostral, an uninterrupted light stripe between the 
rostral and eye, and the virtual absence of spotting on the venter of 
the head and neck.
    The Alameda whipsnake is typically found in northern coastal scrub, 
coastal sage scrub and chaparral plant communities (Ornduff 1974, Swaim 
1994), but may also occur in adjacent grasslands and oak and oak/bay 
woodlands (Swaim 1994). They demonstrate a preference for open-canopy 
stands and habitats with woody debris and exposed rock outcrops, and 
they tend to be found on southeast, south, and southwest facing slopes 
(Swaim 1994). This extremely fast-moving snake holds its head high off 
the ground to peer over grass or rocks for potential prey and is an 
active diurnal predator. Its diet includes lizards, small mammals, 
snakes, and nesting birds.
    Radiotelemetry data suggest that Alameda whipsnakes can occupy home 
ranges varying in size from 1.9 to 8.7 hectares (ha) (5.0 to 21.5 acres 
(ac)). Home ranges of marked snakes overlapped (Swaim 1994). Some 
animals were recorded to have moved over 1.8 kilometers (km) (1 mile 
(mi)) while crisscrossing their areas (McGinnis 1992).
    Alameda whipsnakes breed from March through June, with mating 
appearing to occur near the hibernacula of the female (Swaim 1994). 
Whipsnakes lay clutches of 6 to 11 eggs, May through July (Stebbins 
1985), and the young hatch and emerge in the late-summer to early-fall 
(Swaim 1994).

Previous Federal Action

    A proposed rule to list the callippe silverspot butterfly as 
endangered with critical habitat was published on July 3, 1978 (43 FR 
28938). The critical habitat portion of this proposal was withdrawn by 
the Service on March 6, 1979 (44 FR 12382) because of procedural and 
other substantive changes in the Act by the amendments of 1978. The 
Service again published a proposed rule to designate critical habitat 
for the callippe silverspot butterfly on March 28, 1980 (45 FR 20503). 
The proposal to list the callippe silverspot butterfly and the 
reproposal of critical habitat were withdrawn on September 30, 1980 (45 
FR 64607) because the Act amendments of 1978 required that the final 
rule for the species be completed within 2 years after the date of 
publication of the proposal to list it as endangered or threatened. 
This insect was listed as a category 2 candidate species in the Animal 
Notice of Review on May 22, 1984 (49 FR 21664) and January 6, 1989 (54 
FR 554). Category 2 species were those taxa for which the Service had 
data that indicated listing was possibly appropriate, but for which 
substantial data on their biological vulnerability and threats was not 
currently available to support issuance of proposed listing rules. The 
callippe silverspot butterfly was listed as a category 1 species in the 
Animal Notice of Review on November 21, 1991 (56 FR 58804), because of 
increased threats from overcollecting (see Factor B in the ``Summary of 
Factors Affecting the Species'' section of this rule). Category 1 
species were those taxa for which the Service had on file sufficient 
information on biological vulnerability and threats to support proposed 
listing rules. As announced in a notice published in the February 28, 
1996, Federal Register (61 FR 7596), the designation of multiple 
categories of candidates has been discontinued, and only former 
category 1 species are now recognized as candidates for listing 
purposes.
    Ms. Dee Warenycia petitioned the Service to list the callippe 
silverspot butterfly as an endangered species in a letter dated January 
14, 1991, which was received on January 22, 1991. The Service completed 
a status review and determined that sufficient information existed to 
propose the species for listing. The 12-month petition finding was 
published on February 4, 1994, with the proposed rule (59 FR 5377).
    On March 20, 1975, Behren's silverspot butterfly was listed as one 
of 42 insects whose status was being reviewed for listing as either 
endangered or threatened by the Service (40 FR 12691). This insect was 
listed as a category 2 species in the Animal Notice of Review on May 
22, 1984 (49 FR 21664), and January 6, 1989 (54 FR 554). Dr. Dennis 
Murphy of Stanford University petitioned the Service to list Behren's 
silverspot butterfly as an endangered species in a letter dated June 
28, 1989, which was received on June 29, 1989. The Service determined 
that the petition contained substantial information indicating that the 
action requested may be warranted and published notice of the 90-day finding on November 1, 1990 (55 FR 
46080). It was listed as a category 1 species in the Animal Notice of 
Review on November 21, 1991 (56 FR 58804), on the basis of significant 
increases in habitat loss and threats occurring throughout its range. 
The 12-month petition finding was published with the proposed rule to 
list the species on February 4, 1994 (59 FR 5377).
    On September 18, 1985, the Service published the Vertebrate 
Wildlife Notice of Review (50 FR 37958) which included the Alameda 
whipsnake as a category 2 candidate species for possible future listing 
as endangered or threatened. The January 6, 1989, Animal Notice of 
Review (54 FR 554) solicited information on its status as a category 2 
candidate species. The Alameda whipsnake was moved to category 1 in the 
November 21, 1991, Animal Notice of Review (56 FR 58804) on the basis 
of significant increases in habitat loss and threats occurring 
throughout its range. On February 4, 1994, the Service published a 
proposed rule in the Federal Register (59 FR 5377) to list the Alameda 
whipsnake as an endangered species.
    The processing of this final rule follows the Service's listing 
priority guidance published in the Federal Register on December 5, 1996 
(61 FR 64475). This guidance clarifies the order in which the Service 
will process rulemakings following two related events--(1) the lifting, 
on April 26, 1996, of the moratorium on final listings imposed on April 
10, 1995 (Public Law 104-6), and (2) the restoration of significant 
funding for listing through passage of the Omnibus Budget 
Reconciliation Act following severe funding constraints imposed by a 
number of continuing resolutions between November 1995 and April 1996. 
Under this guidance, highest priority (Tier 1) is given to processing 
emergency listings, and second highest priority (Tier 2) is given to 
resolving the listing status of outstanding proposed listings. The 
third highest priority (Tier 3) is assigned to resolving the 
conservation status of candidate species and processing administrative 
findings on petitions to add species to the lists or reclassify species 
from threatened to endangered status. The lowest priority (Tier 4) is 
given to processing critical habitat determinations, delistings, and 
other types of reclassifications. Processing of this final rule is a 
Tier 2 action.

Summary of Comments and Recommendations

    In the February 4, 1994, proposed rule (59 FR 5377) and associated 
notifications, all interested parties were requested to submit factual 
information that might assist the Service in determining whether these 
taxa warrant listing. Appropriate State and Federal agencies, county 
governments, scientific organizations, and other interested parties 
were contacted and requested to comment. Notices of this proposal were 
published in the San Francisco Chronicle and San Mateo Times on 
February 8, 1994, and the Oakland Tribune on February 10, 1994.
    During the comment period, the Service received comments from 16 
commenters. Six commenters supported the listing of all three taxa. 
Five commenters supported the listing of the callippe silverspot. The 
East Bay Regional Park District (EBRPD) supported the listing of the 
Alameda whipsnake. One commenter provided information on conservation 
methods for the callippe silverspot, but did not express an opinion on 
the listing. Letters from the City of Danville, California Department 
of Parks and Recreation (CDPR), and the U.S. National Biological Survey 
(now the Biological Resources Division of the U.S. Geological Survey) 
provided additional information on the Alameda whipsnake but did not 
express an opinion on the listing. No public hearing was requested.
    On November 1, 1996, the Service published in the Federal Register 
(61 FR 56501) a notice reopening the comment period for 30 days for 
these taxa. The basis for this reopening was the length of time that 
had elapsed since closure of the initial comment period, changing 
procedural and biological circumstances, and the need to review the 
best scientific information available during the decision-making 
process. Specifically, the Service requested information regarding--(1) 
the known or potential effects of fire suppression and general fire 
management practices on the Alameda whipsnake and its habitat; (2) any 
other threats to these taxa; and (3) the size, number, or distribution 
of populations of these taxa. During the 30-day reopened comment 
period, the Service received comments from 10 entities and individuals. 
One commenter stated that the listing of the callippe silverspot 
butterfly would not be beneficial. Two commenters supported listing of 
all three taxa and one commenter expressed no opinion on the listing of 
all three taxa. The remaining letters mentioned only the Alameda 
whipsnake, with two supporting the listing, one opposing the listing, 
and three expressing no opinion. In accordance with the Service policy 
on peer review, published in the Federal Register on July 1, 1994 (59 
FR 34270), the opinions of three independent scientists were also 
solicited. No responses were received from these specialists.
    The Service has reviewed all of the written comments described 
above. New information received since publication of the proposed rule 
is incorporated in the ``Background'' and ``Summary of Factors 
Affecting the Species'' sections of this final rule. The issues raised 
in comments received and the Service's responses are summarized as 
follows:
    Issue 1: One commenter disagreed that the Alameda whipsnake would 
not be impacted by construction and operation of the proposed Los 
Vaqueros Reservoir. The commenter stated that the snake would be 
adversely affected by the reservoir project if there are historic 
records of the snake from the areas that would be inundated.
    Service Response: The quarrying operations for the Los Vaqueros 
project will not be undertaken at the location first proposed for the 
project, where an Alameda whipsnake was observed (Jones and Stokes 
1992). The Service is not aware of any records showing that this 
species had ever occurred in the inundation zone.
    Issue 2: One commenter stated that feral pigs (Sus scrofa) prey on 
snakes and other wildlife.
    Service Response: The Service has incorporated this information in 
this final rule.
    Issue 3: One commenter believed that commercial collecting of the 
Alameda whipsnake was an overstated threat and contended that this was 
incorrectly used as a justification for not designating critical 
habitat. Another commenter stated that the location of the callippe 
silverspot butterfly population at San Bruno Mountain was well known to 
butterfly collectors. He asserted that the threat of collecting was not 
a justification for determining that designation of critical habitat is 
not prudent for the callippe silverspot butterfly.
    Service Response: Under section 4(a)(3)(A) of the Act and 50 CFR 
424.12, the Secretary must designate critical habitat if such 
designation is prudent and determinable. Section 4(b)(2) of the Act 
further states that any area may be excluded from critical habitat if 
it is determined that the benefits of such exclusion outweigh the 
benefits of specifying such area as part of the critical habitat. In 
the case of the Alameda whipsnake and callippe silverspot butterfly, the Service 
believes that designation of critical habitat for these species would 
confer little, if any, conservation benefit to these species beyond 
that provided by listing. Application of the statute and its 
regulations are described in more detail in the ``Critical Habitat'' 
section of this rule.
    Issue 4: Several commenters contended that the failure of the San 
Bruno Mountain Habitat Conservation Plan (HCP) is the primary cause of 
the decline of the callippe silverspot butterfly.
    Service Response: In 1982, a Section 10(a)(1)(B) incidental take 
permit was issued to the cities of Brisbane, Daly City, South San 
Francisco, and the County of San Mateo for the endangered mission blue 
butterfly (Icaricia icarioides missionensis), San Bruno elfin butterfly 
(Incisalia mossii bayensis), and San Francisco garter snake (Thamnophis 
sirtalis tetrataenia). This permit and HCP is described in the 
``Available Conservation Measures'' section of this rule. The Service 
is not aware of any documented evidence or data showing that the 
callippe silverspot butterfly is declining as a result of the San Bruno 
Mountain HCP. However, the HCP does not regulate collecting threats to 
the callippe silverspot butterfly or other butterfly species inhabiting 
San Bruno Mountain. Listing the callippe silverspot butterfly will 
provide this species with regulatory protection from collection and 
other impacts.
    Issue 5: One commenter thought that designation of San Bruno 
Mountain as critical habitat for the callippe silverspot butterfly 
would lead to increased levels of environmental review and greater 
protection for the species.
    Service Response: Critical habitat extends additional protection to 
listed species through section 7 of the Act by requiring that Federal 
agencies ensure that any actions they fund, authorize, or carry out do 
not destroy or adversely modify critical habitat. However, because 
development activities on callippe silverspot butterfly habitat on San 
Bruno Mountain have already been completed, designation of critical 
habitat would not provide additional benefits to the species. A section 
10(a)(1)(B) HCP currently protects habitat in the area.
    Issue 6: One commenter was concerned that particulate matter from 
vehicle exhaust and quarry operations may pose a significant threat to 
the callippe silverspot butterfly.
    Service Response: The adult and early stages of the callippe 
silverspot butterfly and other lepidopterans may be prone to injury and 
mortality from dust because their respiratory apparatus (spiracles) are 
easily clogged. The Service is concerned that high levels of dust from 
quarry operations on San Bruno Mountain may adversely affect the 
butterflies in areas immediately bordering this location.
    Issue 7: One commenter claimed that the three species are being 
used by environmentalists as ``roadblocks'' to economic uses of private 
property. Another commenter stated that public lands should be managed 
for productivity and sustainability and that the economic impact, 
customs, traditions and culture of local communities should be 
considered during the listing process.
    Service Response: Under section 4(a)(1)(A) of the Act, a listing 
determination must be based solely on the best scientific and 
commercial data available. The legislative history of this provision 
clearly states the intent of Congress to ``ensure'' listing decisions 
are ``based solely on biological criteria and to prevent non-biological 
considerations from affecting such decisions'' (H.R. Rep. No. 97-835, 
97th Cong. 2d Sess. 19 (1982)). As further stated in the legislative 
history, ``* * * economic considerations have no relevance to 
determinations regarding the status of species * * *.'' Because the 
Service is specifically precluded from considering economic impacts, 
either positive or negative, in a decision on listing any species, the 
Service does not evaluate or consider the economic impacts of listing 
these species.
    Section 2(a)(3) of the Act recognizes that species of fish, 
wildlife, and plants are of esthetic, ecological, educational, 
historical, recreational, and scientific value to the Nation and its 
people. The Service recognizes that the species included in this 
listing have esthetic, ecological, education, historical and scientific 
value.
    Issue 8: One commenter thought it would be prudent for the Service 
to indicate the percentage of Alameda whipsnake habitat lost since 
1971, the year the species was listed as ``threatened'' under the 
California Endangered Species Act, to document the level of protection 
afforded the species with State listing.
    Service Response: The Service mapped Alameda whipsnake habitat that 
was extant in 1970 and identified areas where conversion and 
encroachment into potential habitat had occurred from then until 1996. 
To the extent determinable from aerial photographs and slides, projects 
impacting habitat during the 1970-1996 period were mapped. Such 
projects included road construction and widening, subdivision 
construction and expansion, and brush removal. Approximately 25 
projects in Alameda County and 41 projects in Contra Costa County 
either converted or encroached upon chaparral in the 1970-1996 period. 
The extent of conversion and encroachment ranged from approximately 0.8 
to 2.0 ha (2 to 5 ac) to approximately 8 to 20 ha (20 to 50 ac) for 
larger projects. Freeway construction and residential and commercial 
development have added dispersal barriers measuring up to 4.8 km (3.0 
mi) wide. The Service's conclusion, from this review, was that regional 
development has significantly fragmented the remaining Alameda 
whipsnake populations and that natural genetic exchange between the 
five remaining populations is unlikely.
    A precise assessment of the amount of habitat loss is difficult, 
because Alameda whipsnakes are known to use adjacent habitats at a high 
level (McGinnis 1992), and may be found at distances up to 
approximately 500 meters (1,640 feet) from scrub and chaparral habitat 
and utilize riparian habitat as a corridor (Swaim 1994). The 
substantial amount of habitat loss documented by the Service brings 
into question the effectiveness of current regulatory protection which 
is further discussed under factor D in the ``Summary of Factors'' 
section of this rule.
    The issues raised in comments received during the 30 days that the 
comment period was reopened and the Service's responses to these issues 
are summarized as follows:
    Issue 9: Several commenters noted the benefits of fuels management 
for snake habitat maintenance and public safety. One commenter noted 
the difficulty in conducting prescribed burns near residential 
communities. Another commenter recommended that the Service explicitly 
recognize the tradeoff between protecting individual snakes from 
mortality during fuels management and the benefits of maintaining long-
term suitable habitat conditions. The commenter further noted that 
restrictions on fuels treatment activities should meet appropriate 
standards for reasonableness, given the critical need to provide for 
public safety.
    Service Response: The subject of the effects of fire suppression 
and general fire management practices on the Alameda whipsnake and its 
habitat was a factor in deciding to reopen the comment period. The 
Service is concerned that fire suppression has had, and continues to 
have, negative impacts on habitat for the Alameda whipsnake. Fire suppression is discussed in 
depth under factor E of the ``Summary of Factors'' section of this 
rule. The Service also recognizes the need for efficient fire control 
in urban areas and would work with appropriate management agencies to 
develop fuels management plans that protect the public while affording 
the maximum practicable conservation benefit to Alameda whipsnakes.
    Issue 10: One commenter expressed concern that the proposed rule to 
list these taxa may not have complied with the regulatory policies 
announced by the Department of the Interior on July 1, 1994. In 
particular, the commenter expressed concern that the listing proposal 
had not been subjected to peer review, as required by the Notice of 
Policy Statement published in the Federal Register on that date (59 FR 
34270).
    Service Response: The proposed rule to list these taxa was 
published on February 4, 1994 (59 FR 5377), predating the Service's 
formal policy on peer review made final on July 1, 1994 (59 FR 34270). 
However, the list of interested parties to whom the Service sent the 
proposed rule for comment included several experts on the life history, 
taxonomy, and ecology of the taxa proposed for listing. During the 
reopened comment period discussed above in the ``Previous Federal 
Actions'' section, the opinions of three independent specialists were 
solicited in accordance with this policy. No responses were received 
from these specialists.
    Issue 11: One commenter noted that because California has 
experienced severe fires during the past several years, fire 
suppression may not be a threat to the Alameda whipsnake.
    Service Response: Several areas of California, particularly 
southern California, have recently experienced wildfires. Within the 
range of the Alameda whipsnake, however, there have been few large 
wildfires within the last 10 years with the notable exception of the 
Oakland Hills firestorm of 1991. Although this fire occurred within the 
range of the species, the burned areas were mostly located in developed 
portions of the Oakland Hills that did not contain habitat suitable for 
the whipsnake. Fire suppression practices that do not include 
controlled burning can lead to severe fires that damage both urban and 
wildlife areas, whereas controlled burning can benefit both wildlife 
habitat and reduce the risk of catastrophes such as the 1991 fire. Fire 
suppression is discussed in detail under factor E of the ``Summary of 
Factors'' section of this rule.
    Issue 12: One commenter was concerned over the method by which 
information was gathered on private property.
    Service Response: The Service is not aware of any information that 
was gathered without the permission of the property owner. Information 
was obtained from Environmental Impact Reports or Statements that are 
required under the California Environmental Quality Act (CEQA) or 
National Environmental Protection Act, reports and data summaries 
prepared by State agencies and independent scientists, information 
submitted during public comment periods, and other information 
published in the scientific journals or available in student 
dissertations.
    Issue 13: One commenter stated that the Service did not use sound 
scientific information as indicated by its use of phrases such as ``may 
be threatened.''
    Service Response: Section 4(b)(a)(A) of the Act requires that 
listing determinations be based on the best scientific and commercial 
data available. The Service has relied on the best available scientific 
and commercial data in making this listing determination. The data upon 
which this determination is based were collected by the petitioners and 
qualified scientists. The phrase ``may be threatened,'' in particular, 
is used to indicate that a potential threat may become an actual one in 
the foreseeable future. The Service believes that it is sound and 
responsible science to acknowledge a lack of absolute certainty when 
that is the case.
    Issue 14: One commenter asked what scientific information was used 
to determine what constitutes ``inappropriate grazing levels.''
    Service Response: The final rule includes livestock grazing as one 
of many factors affecting the species, and ranks it as a contributing 
factor, rather than as a major factor. Indeed, this final rule states 
that some grazing could help to keep other plants from outcompeting the 
butterflies' host plants. Studies on Alameda whipsnakes that have been 
equipped with radiotelemetry units have shown that the whipsnake 
forages in grassland between stands of scrub. Livestock grazing that 
significantly reduces or eliminates plant cover in these grasslands 
would lead to an increased loss of snakes and their prey to other 
predators. The Service believes that livestock grazing, if 
appropriately managed, can benefit both the Alameda whipsnake and the 
two species of butterflies.
    Issue 15: One commenter stated that involvement of State and local 
governments, as well as all types of land users, should be required 
prior to listing a species.
    Service Response: To solicit comments from the public, a notice of 
the February 4, 1994, proposed rule (59 FR 5377) was published in the 
San Francisco Chronicle and San Mateo Times on February 8, 1994, and in 
the Oakland Tribune on February 10, 1994. In addition, appropriate 
State agencies, county governments, Federal agencies, scientific 
organizations, and other interested parties were contacted and 
requested to comment. On November 1, 1996 (61 FR 56501), the Service 
reopened for public comment the proposed listing of the three species 
with a closing date of December 2, 1996, to allow further comments from 
the public.
    Issue 16: One commenter stated that the expense of amending the San 
Bruno Mountain HCP to permit incidental take of callippe silverspot 
butterflies would preclude other habitat management activities.
    Service Response: The Service will work with the permit holders 
involved in the San Bruno Mountain HCP to ensure that the process of 
amending their Section 10(a)(1)(B) permit will not cause undue 
diversion of funding from other habitat management activities.

Summary of Factors Affecting the Species

    After a thorough review and consideration of all information 
available, the Service has determined that the callippe silverspot 
butterfly (Speyeria callippe callippe) and Behren's silverspot 
butterfly (Speyeria zerene behrensii) should be classified as 
endangered species, and the Alameda whipsnake (Masticophis lateralis 
euryxanthus) should be classified as a threatened species. Procedures 
found at section 4(a)(1) of the Act and regulations (50 CFR part 424) 
implementing the listing provisions of the Act were followed. A species 
may be determined to be endangered or threatened due to one or more of 
the five factors described in section 4(a)(1). These factors and their 
application to the callippe silverspot butterfly (Speyeria callippe 
callippe), Behren's silverspot butterfly (Speyeria zerene behrensii), 
and Alameda whipsnake (Masticophis lateralis euryxanthus) are as 
follows:

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Habitat or Range

    The primary causes of the decline in the callippe silverspot 
butterfly and Behren's silverspot butterfly is the loss and degradation of habitat 
from human activities, including off-road vehicle use, trampling by 
hikers and equestrians, inappropriate levels of livestock grazing, and 
invasive exotic vegetation. Off-road vehicles and uncontrolled off-
trail foot traffic pose a threat to the colonies of the two butterfly 
species. These activities could harass, injure, or kill individuals of 
the two species by trampling or crushing the early life stages, the 
foodplants of the larvae, or the adults' nectar sources. The Behren's 
silverspot butterfly also is imperiled by residential and commercial 
development.
    The callippe silverspot butterfly was once considerably more 
widespread in the San Francisco Bay area, and at least five populations 
of this species have been eliminated by urban development and other 
causes. The species was known historically from 14 sites in San Mateo, 
Alameda, Sonoma, and Solano counties, only 2 of which are still extant. 
One of the known extant populations of the callippe silverspot 
butterfly is located in a city park in Alameda County. This colony is 
small and likely to be imperiled by anthropogenic and natural causes 
(S. Mattoon, in litt., November 22, 1992). The population at San Bruno 
Mountain in San Mateo County is largely protected against further loss 
of habitat, which will remain undeveloped in perpetuity by virtue of 
the San Bruno Mountain HCP (Thomas Reid Associates 1982; S. Mattoon, in 
litt., November 22, 1992). However, overcollection of specimens by 
lepidopterists at San Bruno Mountain and at sites where hybrids can be 
found in Solano County continues to pose a threat (see Factor B).
    Behren's silverspot butterfly has been extirpated from a 
significant portion of its former range, which extended from the mouth 
of the Russian River in Sonoma County north to southern Mendocino 
County. One of the six historically known colonies was eliminated by a 
housing development (S. Mattoon, in litt., August 7, 1989). Currently, 
this species is known from a single locality near Point Arena in 
Mendocino County (Sally DeBecker, Pacific Gas and Electric, in litt., 
1990). The site is subject to grazing by livestock. Although no 
development plans have been proposed for this site, urban development 
is occurring in the vicinity. No specimens have been observed at the 
sites of the other historically known colonies since 1987.
    The current threats to the habitat of the Alameda whipsnake are 
urban development and associated impacts due to increased population 
densities, inappropriate grazing practices, and alteration of suitable 
habitat from fire suppression (see factor E below for a full discussion 
of the effects of fire suppression on Alameda whipsnake habitat). The 
central and western portions of Alameda and Contra Costa counties are 
highly urbanized and continue to be subject to increased urbanization. 
Habitat fragmentation from urban development and associated highway and 
road construction has led to isolation of the five populations by 
wholly preventing or severely reducing movement of individuals between 
areas of suitable habitat as described earlier in this rule. These 
activities have also reduced the total amount of suitable habitat 
available for the Alameda whipsnake. Swaim (1994) listed 55 historical 
localities for this species, of which only 25 are considered to be 
extant.
    McGinnis (1992) documented colonies scattered throughout the range 
of the snake that are likely to be adversely impacted by various 
residential developments. In addition, the Service has identified 
numerous housing developments that threaten the Alameda whipsnake 
populations. Some housing developments in Alameda County will further 
fragment habitat areas of the Hayward-Pleasanton Ridge population. 
These developments include the proposed 200 ha (500 ac) Schaefer Ranch 
Project with approximately 474 homes, and the 58 ha (146 ac) Hansen 
Ranch Project, both of which could potentially impact suitable habitat 
for the Alameda whipsnake. The Schaefer Ranch contains suitable habitat 
and the adjacent Hansen Ranch is in close proximity to an Alameda 
whipsnake sighting (California Department of Fish and Game (CDFG), in 
litt., February 13, 1996). In addition, the proposed dedication of 
approximately 64 ha (161 ac) of the Schaefer Ranch project to the EBRPD 
will increase public use and associated recreational impacts to habitat 
of the Alameda whipsnake. The proximity of urban development will also 
increase the likelihood of predation from domestic and feral cats to 
EBRPD lands that are otherwise protected from development (DelVecchio 
1997) (see factor C below).
    Two other proposed projects to the south affect the Hayward-
Pleasanton Ridge population. The 632 ha (1,580 ac) Hayward 1900 project 
and the 156 ha (391 ac) Bailey Ranch are adjacent housing developments 
along Walpert Ridge in Hayward (Planning Collaborative 1995, City of 
Hayward 1996). Both the Walpert Ridge and the Bailey Ranch sites have 
habitat occupied by the Alameda whipsnake (McGinnis 1992). In addition, 
contiguous habitat exists between known occupied habitat to the west 
and east of the Bailey Ranch and Hayward 1900 development projects. 
Although Bailey Ranch has proposed mitigation to offset impacts to the 
Alameda whipsnake, both developments will further impact and fragment 
the Hayward-Pleasanton Ridge population. Hayward 1900 has proposed open 
space but is planning to construct trails and vineyards in the proposed 
open space (Planning Collaborative 1995). Vineyards, associated 
agricultural land uses, and trails could eliminate and fragment 
whipsnake habitat and further restrict the movement of snakes.
    Within the Oakland-Las Trampas population, several proposed 
developments may impact Alameda whipsnakes and their habitat. Several 
of these proposed projects are located contiguous to the east side of 
Las Trampas Regional Wilderness and contain habitat known to be 
occupied by Alameda whipsnakes. The proposed 9 ha (22 ac) Rossmoor 
Neighborhood Nine Project would result in the direct loss of snake 
habitat and could potentially impact mitigation habitat previously 
provided to offset impacts from an earlier phase of the project (CDFG, 
in litt., November 25, 1995). The proposed expansion of the Oakland Zoo 
could potentially impact suitable snake habitat (K. Swaim and S. 
McGinnis, Hayward State University, pers. comm., 1996). Some of these 
projects have, or may, set aside suitable habitat for the Alameda 
whipsnake, preserved either as open space or as mitigation for habitat 
losses associated with the project. Although these proposed 
developments may mitigate for impacts to Alameda whipsnakes, the 
undeveloped hillsides that support chaparral growth will be subject to 
increased fire suppression due to the close proximity of urban 
development. This fire suppression will result in habitat degradation 
and an increased probability of catastrophic wildfires as discussed 
under factor E below.
    The Mount Diablo-Black Hills, Tilden-Briones, and Sunol-Cedar 
populations are indirectly threatened by urban development. The Mount 
Diablo-Black Hills population will be adversely affected by the urban 
expansion of the cities of Pittsburg, Oakley, Brentwood, and Antioch. 
These cities are projected to expand by over 40,000 units, which will 
result in increased visitation and associated impacts to nearby EBRPD parks and Mt. Diablo State Park. 
Specific developments such as the 115-unit Clayton Ranch (412 ha (1,030 
ac)) and 5,200-unit Cowell Ranch (1,709 ha (4,272 ac)) will expose the 
eastern flank of the Mt. Diablo-Black Hills population to these 
indirect impacts of urbanization. The Mt. Diablo-Black Hills population 
is also subject to increased urban impacts on the south side from the 
proposed Dougherty Valley (2,400 ha (6,000 ac)) and Tassajara Valley 
(1,600 ha, (4,000 ac)) projects, which total over 17,000 units. The 
Tilden-Briones population will be subject to increased population 
pressure from the north by the approved 800-unit Franklin Canyon (392 
ha (980 ac)) projects (Mooers, 1996). Additional developments are 
approved or proposed adjacent to the Sunol-Cedar population in the 
rapidly growing areas near Dublin and Pleasanton in Alameda County. 
These projects will increase human disturbance from recreational use on 
regional and state parks, and as urban development encroaches into the 
current open space buffers between existing developments and whipsnake 
habitat on public lands, the threat of predation and harassment from 
domestic and feral cats increases (Coleman et al. 1997). Predation 
threats are discussed in more detail under factor C below.
    The past and ongoing fragmentation of Alameda whipsnake habitat 
makes some populations of this species more vulnerable to extinction. 
The Tilden-Briones and Oakland-Las Trampas populations occupy a narrow, 
interrupted band of ridgetop chaparral dividing the heavily urbanized 
Oakland/Berkeley region to the west from the rapidly urbanizing Highway 
680 corridor to the east (USGS 1997). Habitat patches with high ratios 
of edge to interior are known to provide less value for some species 
than round or square patches provide (Jimerson and Hoover 1991; 
Saunders et al. 1991). In fragmented habitats, species most prone to 
extinction are those that depend on native vegetation, require 
combinations of different habitat types, require large territories, and 
exist at low densities (Saunders et al. 1991). Alameda whipsnakes have 
been shown to be associated with native Diablan sage scrub, to forage 
in adjacent grasslands, and to migrate along riparian corridors. While 
the home range of the Alameda whipsnake, estimated to vary between 2 
and 9 ha (5 and 20 ac), is not large compared to that of some animals, 
the narrow habitats of the Tilden-Briones and Oakland-Las Trampas 
populations, less than 1.6 km (1 mi) wide in some places, may impose a 
significant constraint on the species. Few individuals have been 
captured during trapping studies conducted over thousands of trap days, 
indicating that Alameda whipsnakes may be sparse even in suitable 
habitat (Swaim 1994). These factors may combine to cause Alameda 
whipsnakes to be vulnerable to extinction in small habitat patches 
resulting from habitat fragmentation.

B. Overutilization for Commercial, Recreational, Scientific or 
Educational Purposes

    The callippe silverspot butterfly and Behren's silverspot butterfly 
are highly prized by insect collectors. Although no studies 
specifically document the impact of the removal of individuals on 
natural populations of either butterfly species, based on studies of 
another endangered nymphalid butterfly (Gall, 1984a and 1984b) and a 
lycaenid butterfly (Duffey 1968), both butterflies are vulnerable to 
impacts from collection due to their isolated, possibly small 
populations. Butterfly collectors have been observed on San Bruno 
Mountain (S. Stern, in litt., June 21, 1994). Some of these specimens 
are being traded for other butterfly taxa or are being held by the 
collectors in anticipation of their greater value should the species be 
listed. The Service also is aware of reports that Behren's silverspot 
butterfly is actively sought by amateur lepidopterists. Both collecting 
from small colonies and scientific studies that repeatedly handle and 
mark individuals (particularly of females and in years of low 
abundance) could seriously damage the populations through loss of 
individuals and the resulting loss of genetic variability within the 
population (Singer and Wedlake 1981, Gall 1984b, Murphy 1988). 
Collection of females dispersing from a colony also can reduce the 
probability that new colonies will be founded. Collectors pose a threat 
because they may be unable to recognize when they are depleting 
butterfly colonies below the thresholds of survival or recovery, 
especially when they lack appropriate biological training or when they 
visit the area for a short period of time (Collins and Morris 1985).
    An extensive commercial trade has been documented for the callippe 
silverspot butterfly and the Behren's silverspot butterfly, as well as 
for other imperiled and rare butterflies (U.S. Attorney's Office 1994, 
United States v. Richard J. Skalski, Thomas W. Kral, and Marc L. 
Grinnell, Case No. CR932013, 1993). The Service is concerned that 
issuance of a final rule for these animals that is not effective 
immediately upon publication will result in greatly intensified level 
of collecting and commercial trade in the callippe silverspot butterfly 
and Behren's silverspot butterfly. Because of the immediate threat 
posed by these on-going activities, the Service finds that good cause 
exists for this rule to take effect immediately upon publication in 
accordance with 5 U.S.C. 553(d)(3).
    The Alameda whipsnake does not appear to be particularly popular 
among reptile collectors; however, Federal listing could raise the 
value of the animals within reptilian trade markets and increase the 
threat of unauthorized collection above current levels (K. McCloud, 
U.S. Fish and Wildlife Service, Law Enforcement Division, pers. comm., 
1994 and 1996). Even limited interest in the species among reptile 
collectors could pose a serious threat to smaller populations of the 
snake.

C. Disease or Predation

    It appears that predation or disease do not pose a significant 
threat to the callippe silverspot butterfly or Behren's silverspot 
butterfly. The potential impact of disease on the Alameda whipsnake is 
unknown.
    A number of native and exotic mammals and birds are known or likely 
to be predators of the Alameda whipsnake including the California 
kingsnake (Lampropeltis getula californiae), raccoon (Procyon lotor), 
striped skunk (Mephitis mephitis), opossum (Didelphis virginianus), 
coyote (Canis latrans), gray fox (Vulpes cinereoargenteus), and hawk 
(Buteo species). Urbanization can lead to increased numbers and access 
to habitat by native predators, leading to increased levels of 
predation on native fauna (Goodrich and Buskirk 1995). The recent 
introduction of the red fox (Vulpes vulpes), a species not native to 
this region of the State, poses an additional threat to the Alameda 
whipsnake. In situations where Alameda whipsnake habitat has become 
fragmented, isolated, and otherwise degraded by human activities, 
increased predatory pressure may become excessive, especially where 
alien species, such as rats (Rattus species), feral pigs (Sus scrofa), 
and feral and domestic cats (Felis domestica) and dogs (Canis 
familiaris) are introduced. These additional threats become 
particularly acute where urban development immediately abuts Alameda 
whipsnake habitat. A growing movement to maintain feral cats in 
parklands is an additional potential threats from predation on wildlife (Coleman et al. 1997, Roberto 1995). 
The EBRPD is currently facing public pressure to allow private 
individuals to maintain feral cats on park lands (DelVecchio 1997). 
Although the actual impact of predation on Alameda whipsnakes under 
such situations has not been studied, feral cats are know to prey on 
reptiles, including yellow racers (Hubbs 1951), a fast, diurnal snake 
closely related to the Alameda whipsnake (Stebbins 1985). Predation 
pressure on Alameda whipsnakes may increase from maintained colonies of 
feral cats in Alameda whipsnake habitat.

D. The Inadequacy of Existing Regulatory Mechanisms

    The callippe silverspot butterfly and Behren's silverspot butterfly 
are not specifically protected under any Federal, State or local law. 
The California Endangered Species Act (CESA) does not provide 
protection to insects (sections 2062, 2067 and 2068, Fish and Game 
Code). Although the San Bruno Mountain HCP provides protection from 
habitat destruction, butterfly collectors have been observed on San 
Bruno Mountain (S. Stern, in litt., June 21, 1994) and unauthorized 
collection remains an ongoing threat. The extent of illegal trade in 
these and other butterfly species and the potential threat poaching 
poses to small populations is discussed in detail under factor B above.
    The California Environmental Quality Act (CEQA) requires a full 
public disclosure of the potential environmental impact of proposed 
projects. The public agency with primary authority or jurisdiction over 
the project is designated as the lead agency and is responsible for 
conducting a review of the project and consulting with other agencies 
concerned with resources affected by the project. Section 15065 of the 
CEQA guidelines requires a finding of significance if a project has the 
potential to ``reduce the number or restrict the range of a rare or 
endangered plant or animal.'' Species that are eligible for listing as 
rare, threatened, or endangered but are not so listed are given the 
same protection as those species that are officially listed with the 
State. Once significant impacts are identified, the lead agency has the 
option to require mitigation for effects through changes in the project 
or to decide that overriding considerations make mitigation infeasible. 
In the latter case, projects may be approved that cause significant 
environmental damage, such as destruction of endangered species. 
Protection of listed species through CEQA is, therefore, at the 
discretion of the lead agency. The CEQA provides that, when overriding 
social and economic considerations can be demonstrated, project 
proposals may go forward, even in cases where the continued existence 
of the species may be jeopardized, or where adverse impacts are not 
mitigated to the point of insignificance. In addition, proposed 
revisions to CEQA guidelines, if made final, may weaken protections for 
threatened, endangered, and other sensitive species.
    The CEQA and CESA afford the Alameda whipsnake some conservation 
benefits. The animal was listed as a threatened species by the State of 
California in 1971 (CDFG 1987). Although these State laws provide a 
measure of protection to the species, resulting in the formulation of 
mitigation measures to reduce or offset impacts for projects proposed 
in certain areas of Alameda whipsnake habitat, these laws are not 
adequate to protect the species in all cases. Further, only State, and 
not Federal, agencies are required to consult under CESA. In response 
to a comment on the proposed rule, the Service mapped Alameda whipsnake 
habitat that was extant in 1970 and identified areas where conversion 
and encroachment into suitable habitat has occurred since the State 
listed the Alameda whipsnake as threatened in 1971. Based upon this 
analysis, the Service has determined that approximately 25 projects in 
Alameda County, and approximately 41 projects in Contra Costa County, 
either converted or encroached upon suitable habitat from 1970 to 1996. 
The extent of conversion and encroachment ranged from approximately 2 
to 5 ac to approximately 20 to 50 ac for larger projects. Although some 
of these projects were required to set aside and preserve suitable 
habitat for the Alameda whipsnake as open space or as mitigation for 
habitat losses associated with the project, many of these preserved 
areas remain threatened by fire suppression practices and catastrophic 
wildfire for the reasons identified and discussed in factor E below.
    With appropriate management, areas of open space managed by the 
EBRPD, East Bay Municipal Utilities District (EBMUD), and Mount Diablo 
State Park, conservation strategies for Alameda whipsnake may be 
developed. Although these public lands include substantial areas 
occupied by the whipsnake, the quality of the habitat continues to 
decline because of surrounding urban encroachment. Urban encroachment 
also exacerbates the habitat fragmentation problems, and greatly 
restricts the ability of these agencies to conduct effective fire 
management practices that have the potential to sustain suitable 
habitat for the Alameda whipsnake and prevent catastrophic wildfires.

E. Other Natural or Man-Made Factors Affecting Their Continued 
Existence

    The use of insecticides would threaten the callippe silverspot 
butterfly and the Behren's silverspot butterfly if use occurred in 
proximity to occupied habitat. Silverspot butterfly larvae are 
extremely sensitive to pesticides, and even the accumulation of runoff 
in the soil after spraying has proven lethal to the larvae of members 
of the genus Speyeria (Mattoon et al. 1971). However, the Service is 
not aware of plans to apply insecticides or pesticides on or near the 
habitat occupied by either of these two species.
    Livestock grazing could threaten the two butterfly species if it 
occurs at harmful levels, such that the vegetation is overgrazed and 
the foodplants and nectar sources of these butterflies are eliminated 
or greatly reduced in abundance. Grazing animals can also trample the 
larval foodplants and adult nectar sources. Significant reduction or 
loss of these food sources could threaten the population viability of 
these butterflies. However, some livestock grazing could keep other 
plants from outcompeting the butterflies' host plants.
    McGinnis (1992) has suggested that grazing has impacted the habitat 
of the Alameda whipsnake in many areas east of the Coast Range. 
Livestock grazing that significantly reduces or eliminates shrub and 
grass cover can be detrimental to this snake. Many snake species, 
including the Alameda whipsnake, avoid such open areas because of the 
increased danger from predators and the lack of prey (McGinnis 1992).
    The invasion of California's native grassland and coastal prairie 
by alien plants has adversely affected native flora and fauna. Numerous 
non-native species have invaded these plant communities (Heady 1988, 
Heady et al. 1988). Introduced alien plants, such as iceplant 
(Carprobrotus sp.), gum trees (Eucalyptus spp.), and gorse (Ulex 
europaeus), often outcompete and supplant native vegetation. In the 
absence of control and eradication programs, invasive alien plants may 
eliminate the remaining native plants, including the host plants of 
Behren's and callippe silverspot butterflies. Adequate levels of Viola 
species are especially critical for the long term survival of populations of these 
butterflies (S. Mattoon, in litt., August 4, 1989, and November 22, 
1992). Non-native plants may also replace native vegetation in habitat 
for the Alameda whipsnake, potentially degrading the habitat and 
reducing the prey base. Radiotelemetry data indicate that Alameda 
whipsnakes tend to avoid dense stands of eucalyptus (Swaim 1994).
    Periodic fires can be an important factor in maintaining the 
grassland and coastal prairie habitat of the callippe silverspot 
butterfly and the Behren's silverspot butterfly. Without fire, 
succession will eliminate the foodplants of the larvae of the two 
butterflies (Orsak 1980, Hammond and McCorkle 1984). Periodic cool, 
fast-moving fires appear important for the maintenance of the habitat 
of these two species. Dead grass and other vegetation from previous 
years may not decay quickly enough and may gradually accumulate to form 
a thick layer of thatch that smothers violets. The larvae of the 
silverspot butterflies may survive fires that move rapidly through 
grassland habitats, whereas hotter, slow-moving brush and woodland 
fires may kill them (Orsak 1980, Hammond and McCorkle 1984). In 
addition, under windy conditions, fast-moving grassland fires burn in 
patches that leave ``islands'' of unburned habitat where any 
butterflies present are not harmed.
    The Alameda whipsnake is threatened directly and indirectly by the 
effects of fire suppression. Fire suppression exacerbates the effects 
of wildfires through the buildup of fuel (underbrush and woody debris), 
creating conditions for slow-moving, hot fires as described above. The 
highest intensity fires occur in the summer and early fall when 
accumulated fuel is abundant and dry. During this period, hatchling and 
adult Alameda whipsnakes are aboveground (Swaim 1994), and populations 
are likely to sustain the heaviest losses from fires. The development 
of a closed scrub canopy also results in a buildup of flammable fuels 
over time (Parker 1987, Rundel 1987). Fire suppression has led to the 
encroachment of nonindigenous and ornamental trees into grassland 
habitats, further increasing flammable fuel loads in and around Alameda 
whipsnake habitat.
    Fire suppression can alter the structure of snake habitat by 
allowing plants to establish a closed canopy (Parker 1987) that will 
tend to create relatively cool conditions. Alameda whipsnakes have a 
higher mean active body temperature (33.4 degrees centigrade) and a 
higher degree of body temperature stability (stenothermy) than has been 
documented in any other species of snake under natural conditions 
(Swaim 1994). Alameda whipsnakes apparently can maintain this high, 
stable body temperature by using open and partially open and/or low 
growing shrub communities that provide cover from predators while 
providing a mosaic of sunny and shady areas between which Alameda 
whipsnakes can move to regulate their body temperatures (Swaim 1994). 
Tall, shaded stands of vegetation, such as poison oak (Toxicodendron 
diversilobum), coyote brush (Baccharis pilularis), or other vegetation 
may not provide the optimum temperature gradient for Alameda 
whipsnakes. Survey data show that Alameda whipsnakes are less likely to 
be found where these plant species create a closed canopy (Swaim 1994).
    In addition, many of the native coastal scrub and chaparral plant 
species require periodic fires to stimulate new sprouting, seedling 
recruitment, and seed dispersal (Parker 1987; Keeley 1987, 1992). The 
natural fire frequency necessary to provide this stimulus in this 
habitat type is debated by scientists but ranges from 10 to 30 years 
(Keeley and Keeley 1987, Rundel 1987). Therefore, depending on the rate 
of fuel accumulation, prescribed burns can be conducted in areas where 
fires have been suppressed with a frequency of 10 to 30 years (J. 
Ferreira, CDPR, pers. comm.  

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