[Federal Register Volume 61, Number 101 (Thursday, May 23, 1996)]
[Rules and Regulations]
[Pages 25813-25833]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-12901]



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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AC 34


Endangered and Threatened Wildlife and Plants; Determination of 
Threatened Status for the California Red-Legged Frog

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: The U.S. Fish and Wildlife Service (Service) determines 
threatened status for the California red-legged frog (Rana aurora 
draytonii) pursuant to the Endangered Species Act of 1973, as amended 
(Act). The Service originally proposed to list the California red-
legged frog as endangered, but information obtained during the comment 
period suggests that this taxon is found in more localities within its 
current range than previously identified. The California red-legged 
frog is now found primarily in wetlands and streams in coastal 
drainages of central California. It has been extirpated from 70 percent 
of its former range. The California red-legged frog is threatened 
within its remaining range by a wide variety of human impacts, 
including urban encroachment, construction of reservoirs and water 
diversions, introduction of exotic predators and competitors, livestock 
grazing, and habitat fragmentation. This rule implements the Federal 
protection and recovery provisions afforded by the Act for this 
species.

EFFECTIVE DATE: June 24, 1996.

ADDRESSES: The complete file for this rule is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, 2800 Cottage Way, Room E-1803, Sacramento, 
CA 95825-1846.

FOR FURTHER INFORMATION CONTACT: Karen J. Miller, at the above address 
(916 979-2725).

SUPPLEMENTARY INFORMATION:

Background

    The California red-legged frog (Rana aurora draytonii) is one of 
two subspecies of the red-legged frog (Rana aurora) found on the 
Pacific coast. Rana a. draytonii was first described by Baird and 
Girard in 1852 from specimens collected at or near the City of San 
Francisco in 1841 (Storer 1925, Cochran 1961). The California red-
legged frog is the largest native frog in the western United States 
(Wright and Wright 1949),

[[Page 25814]]

ranging from 4 to 13 centimeters (cm) (1.5 to 5.1 inches (in.)) in 
length (Stebbins 1985). The abdomen and hind legs of adults are largely 
red; the back is characterized by small black flecks and larger 
irregular dark blotches with indistinct outlines on a brown, gray, 
olive, or reddish background color. Dorsal spots usually have light 
centers (Stebbins 1985). Dorsolateral folds are prominent on the back. 
Larvae (tadpoles) range from 14 to 80 millimeters (mm) (0.6 to 3.1 in.) 
in length and the background color of the body is dark brown and yellow 
with darker spots (Storer 1925).
    The historical range of the California red-legged frog extended 
coastally from the vicinity of Point Reyes National Seashore, Marin 
County, California, and inland from the vicinity of Redding, Shasta 
County, California, southward to northwestern Baja California, Mexico 
(Jennings and Hayes 1985, Hayes and Krempels 1986). The northern red-
legged frog (Rana aurora aurora) ranges from Vancouver Island, British 
Columbia, Canada, south along the Pacific coast west of the Cascade 
ranges to northern California (northern Del Norte County). Red-legged 
frogs found in the intervening area (southern Del Norte to northern 
Marin County) exhibit intergrade characteristics of both R. a. aurora 
and R. a. draytonii (Hayes and Krempels 1986). Systematic relationships 
between the two subspecies are not completely understood (Hayes and 
Miyamoto 1984, Green 1985a, Green 1986, Hayes and Krempels 1986). 
However, significant morphological and behavioral differences between 
the two subspecies suggest that they may actually be two species in 
secondary contact (Hayes and Krempels 1986).
    Northern Marin County represents the approximate dividing line 
between R. a. draytonii and the intergrade zone along the coastal range 
(Mark Jennings, National Biological Service, pers. comm., 1993). 
California red-legged frogs found in Nevada (Linsdale 1938, Green 
1985b) were introduced. This rule does not extend the Act's protection 
to any R. aurora in (1) The State of Nevada; (2) Humboldt, Trinity, and 
Mendocino counties, California; (3) Glenn, Lake, and Sonoma counties, 
California, west of the Central Valley Hydrological Basin; or (4) 
Sonoma and Marin counties north and west of the Napa River, Sonoma 
Creek, and Petaluma River drainages, which drain into San Francisco 
Bay, and north of the Walker Creek drainage, which drains to the 
Pacific Ocean.
    Several morphological and behavioral characteristics differentiate 
California red-legged frogs from northern red-legged frogs. Adult 
California red-legged frogs are significantly larger than northern red-
legged frogs by 35 to 40 mm (1.4 to 1.6 in.) (Hayes and Miyamoto 1984). 
Dorsal spots of northern red-legged frogs usually lack light centers 
common to California red-legged frogs (Stebbins 1985), but this is not 
a strong diagnostic character. California red-legged frogs have paired 
vocal sacs and call in air (Hayes and Krempels 1986), whereas northern 
red-legged frogs lack vocal sacs (Hayes and Krempels 1986) and call 
underwater (Licht 1969). Female California red-legged frogs deposit egg 
masses on emergent vegetation so that the egg mass floats on the 
surface of the water (Hayes and Miyamoto 1984). Northern red-legged 
frogs also attach their egg masses to emergent vegetation, but the mass 
is submerged (Licht 1969).
    California red-legged frogs breed from November through March with 
earlier breeding records occurring in southern localities (Storer 
1925). Northern red-legged frogs breed in January to March soon after 
the ice melts (Nussbaum et al. 1983). California red-legged frogs found 
in coastal drainages are rarely inactive (Jennings et al. 1992), 
whereas those found in interior sites may hibernate (Storer 1925).
    The California red-legged frog occupies a fairly distinct habitat, 
combining both specific aquatic and riparian components (Hayes and 
Jennings 1988, Jennings 1988b). The adults require dense, shrubby or 
emergent riparian vegetation closely associated with deep (>0.7 meters 
(m)) still or slow moving water (Hayes and Jennings 1988). The largest 
densities of California red-legged frogs are associated with deep-water 
pools with dense stands of overhanging willows (Salix spp.) and an 
intermixed fringe of cattails (Typha latifolia) (Jennings 1988b). Well-
vegetated terrestrial areas within the riparian corridor may provide 
important sheltering habitat during winter. California red-legged frogs 
estivate in small mammal burrows and moist leaf litter (Jennings and 
Hayes 1994b). California red-legged frogs have been found up to 30 m 
(98 feet (ft)) from water in adjacent dense riparian vegetation for up 
to 77 days (Rathbun et al. 1993, Galen Rathbun, National Biological 
Service, in litt., 1994). Rathbun (in litt., 1994) found that the use 
of the adjacent riparian corridor was most often associated with drying 
of coastal creeks in mid to late summer.
    California red-legged frogs disperse upstream and downstream of 
their breeding habitat to forage and seek estivation habitat. 
Estivation habitat is essential for the survival of California red-
legged frogs within a watershed. Estivation habitat, and the ability to 
reach estivation habitat can be limiting factors in California red-
legged frog population numbers and survival.
    Estivation habitat for the California red-legged frog is 
potentially all aquatic and riparian areas within the range of the 
species and includes any landscape features that provide cover and 
moisture during the dry season within 300 feet of a riparian area. This 
could include boulders or rocks and organic debris such as downed trees 
or logs; industrial debris; and agricultural features, such as drains, 
watering troughs, spring boxes, abandoned sheds, or hay-ricks. Incised 
stream channels with portions narrower than 18 inches and depths 
greater than 18 inches may also provide estivation habitat.
    Egg masses that contain about 2,000 to 5,000 moderate-sized (2.0 to 
2.8 mm (0.08 to 0.11 in.) in diameter), dark reddish brown eggs are 
typically attached to vertical emergent vegetation, such as bulrushes 
(Scirpus spp.) or cattails (Typha spp.) (Jennings et al. 1992). 
California red-legged frogs are often prolific breeders, laying their 
eggs during or shortly after large rainfall events in late winter and 
early spring (Hayes and Miyamoto 1984). Eggs hatch in 6 to 14 days 
(Jennings 1988b). In coastal lagoons, the most significant mortality 
factor in the pre-hatching stage is water salinity (Jennings et al. 
1992). One hundred percent mortality occurs in eggs exposed to salinity 
levels greater than 4.5 parts per thousand (Jennings and Hayes 1990). 
Larvae die when exposed to salinities greater than 7.0 parts per 
thousand (Mark Jennings, National Biological Service, in litt., 1994). 
Larvae undergo metamorphosis 3.5 to 7 months after hatching (Storer 
1925, Wright and Wright 1949, Jennings and Hayes 1990). Of the various 
life stages, larvae probably experience the highest mortality rates, 
with less than 1 percent of eggs laid reaching metamorphosis (Jennings 
et al. 1992). Sexual maturity normally is reached at 3 to 4 years of 
age (Storer 1925, Jennings and Hayes 1985), and California red-legged 
frogs may live 8 to 10 years (Jennings et al. 1992).
    The diet of California red-legged frogs is highly variable. Larvae 
probably eat algae (Jennings et al. 1992). Hayes and Tennant (1985) 
found invertebrates to be the most common food items of adult frogs. 
Vertebrates, such as Pacific tree frogs (Hyla regilla) and California 
mice (Peromyscus californicus), represented over half of the prey mass 
eaten by larger frogs (Hayes and Tennant 1985). Hayes and Tennant 
(1985) found

[[Page 25815]]

juvenile frogs to be active diurnally and nocturnally, whereas adult 
frogs were largely nocturnal. Feeding activity likely occurs along the 
shoreline and on the surface of the water (Hayes and Tennant 1985).
    The California red-legged frog has sustained a 70 percent reduction 
in its geographic range in California as a result of several factors 
acting singly or in combination (Jennings et al. 1992). Habitat loss 
and alteration, overexploitation, and introduction of exotic predators 
were significant factors in the California red-legged frog's decline in 
the early to mid 1900s. It is estimated that California red-legged 
frogs were extirpated from the Central Valley floor before 1960. 
Remaining aggregations (assemblages of one or more individuals, not 
necessarily a viable population) of California red-legged frogs in the 
Sierran foothills became fragmented and were later eliminated by 
reservoir construction, continued expansion of exotic predators, 
grazing, and prolonged drought. Within the Central Valley hydrographic 
basin, only 14 drainages on the Coast Ranges slope of the San Joaquin 
Valley and one drainage in the Sierran foothills are actually known to 
support or may support California red-legged frogs, compared to over 60 
historic locality records for this basin (a 77 percent reduction). The 
pattern of disappearance of California red-legged frogs in southern 
California is similar to that in the Central Valley, except that 
urbanization and associated roadway, large reservoir (introduction of 
exotic predators), and stream channelization projects were the primary 
factors causing population declines. In southern California, California 
red-legged frogs are known from only five locations south of the 
Tehachapi Mountains, compared to over 80 historic locality records for 
this region (a reduction of 94 percent).
    California red-legged frogs are known to occur in 243 streams or 
drainages in 22 counties, primarily in the central coastal region of 
California. The current number of occupied drainages represents 
information obtained during the public comment period and re-evaluation 
of Service records. This re-evaluation resulted in the compilation of a 
threat matrix for all drainages known to support California red-legged 
frogs (U.S. Fish and Wildlife Service 1995). The term ``drainage'' will 
be used to describe named streams, creeks, and tributaries from which 
California red-legged frogs have been observed. For purposes of this 
final rule, a single occurrence of California red-legged frog is 
sufficient to designate a drainage as occupied by, or supporting 
California red-legged frogs. Monterey (32), San Luis Obispo (36), and 
Santa Barbara (36) counties support the greatest number of currently 
occupied drainages. Historically the California red-legged frog was 
known from 46 counties, but the taxon is now extirpated from 24 of 
those counties (a 52 percent reduction in county occurrences). In seven 
of the 22 occupied counties (32 percent), California red-legged frogs 
are known from a single occurrence. The most secure aggregations of 
California red-legged frogs are found in aquatic sites that support 
substantial riparian and aquatic vegetation and lack exotic predators 
(e.g., bullfrogs (Rana catesbeiana), bass (Micropterus spp.), and 
sunfish (Lepomis spp.)). Only three areas within the entire historic 
range of the California red-legged frog may currently support more than 
350 adults, Pescardero Marsh Nature Preserve (San Mateo County), Point 
Reyes National Seashore (Marin County), and Rancho San Carlos (Monterey 
County). The San Francisco Airport drainage location, identified in the 
proposed rule as containing over 350 individuals, is now thought to be 
nearly extirpated. Threats, such as expansion of exotic predators, 
proposed residential development, and water storage projects, occur in 
the majority of drainages known to support California red-legged frogs.

Previous Federal Action

    On January 29, 1992, the Service received a petition from Drs. Mark 
R. Jennings and Marc P. Hayes, and Mr. Dan Holland to list the 
California red-legged frog (Rana aurora draytonii). The petition 
specified endangered or threatened status by distinct drainages 
(watersheds) within the range of the species. On October 5, 1992, the 
Service published a 90-day petition finding (57 FR 45761) that 
substantial information had been presented indicating the requested 
action may be warranted. Public comments were requested and a review of 
the species' status was initiated. The California red-legged frog had 
been included as a Category 1 candidate species in the Service's 
November 21, 1991, Animal Notice of Review (56 FR 58804). Category 1 
candidates (now known simply as candidates) are species for which the 
Service has sufficient information on biological vulnerability and 
threat to support proposals to list them as endangered or threatened. 
On July 19, 1993, the Service published a 12-month finding on the 
petitioned action (58 FR 38553). This finding indicated that listing of 
the California red-legged frog was warranted and that a proposed rule 
would be published promptly. On February 2, 1994 (59 FR 4888), the 
Service published a proposal to list the California red-legged frog as 
an endangered species. Based on new information received during the 
comment period on the proposed rule, the Service now determines the 
California red-legged frog to be a threatened species.

Summary of Comments and Recommendations

    In the February 2, 1994 proposed rule (58 FR 4888) and associated 
notifications, all interested parties were requested to submit factual 
reports or information that might contribute to development of a final 
rule. Appropriate State agencies and representatives, County and City 
governments, Federal agencies and representatives, scientific 
organizations, and other interested parties were contacted and 
requested to comment. Newspaper notices were published in the San 
Francisco Chronicle on February 9, 1994, and the Sacramento Bee on 
February 10, 1994, both of which invited public comment.
    The Service received eight written requests for a public hearing. 
Three requests came from the Mosquito and Vector Control Districts of 
Glenn, Sutter/Yuba, and Butte counties. Additional requests came from 
William Hazeltine, a private consultant; the California Cattlemen's 
Association; the Cambria Community Services District; the United 
Residential Lot Owners of Cambria, Inc.; and Price, Postel, and Parma, 
a Santa Barbara law firm. As a result, the Service published a notice 
of public hearing on April 8, 1994 (59 FR 16792), and reopened the 
comment period until May 27, 1994. Appropriate State agencies and 
representatives, County and City governments, Federal agencies and 
representatives, scientific organizations, and other interested parties 
were contacted regarding the hearing. A newspaper notice of the public 
hearing was published in the Sacramento Bee on April 25, 1994, which 
invited general public comment. A public hearing was conducted at the 
Radisson Hotel in Sacramento, California on May 12, 1994. Testimony was 
taken from 6:00 p.m. to 8:00 p.m. Seventeen individuals testified at 
the hearing.
    During the comment periods, the Service received 72 comments (i.e., 
letters and oral testimony) from 57 individuals or agencies. Of the 31 
commenters that stated a position, 22 (71 percent) supported listing 
and 9 (29 percent) did not.
    Support for the listing was expressed by one State agency 
(California

[[Page 25816]]

Department of Parks and Recreation) and 18 other interested parties. 
Three commenters recommended listing the California red-legged frog as 
threatened. Opposition to the listing was expressed by two mosquito 
abatement or vector control districts and seven other interested 
parties. Of the 26 respondents indicating no position on the listing, 
several expressed concern regarding the impact of listing.
    Written comments and oral statements obtained during the public 
hearing and comment periods are combined in the following discussion. 
Opposing comments and other comments questioning the rule can be placed 
in 10 general groups based on content. These categories of comment, and 
the Service's response to each, are listed below.

Issue 1: Insufficiency of Scientific Data

    Comment: Several commenters stated that insufficient data are 
available to warrant listing of the California red-legged frog. They 
suggested that the distribution of the California red-legged frog is 
more widespread and that many more sites may exist than were reported 
in the proposed rule because surveying within the historic range of the 
taxon has not been complete. One commenter suggested that only easily 
accessible areas on the coast seemed to have been surveyed and if a 
watershed approach had been taken, the range of the species would be 
greater than 30 percent of its historical range. Another commenter 
suggested that many surveys were done in drought years, which would 
bias the data.
    Service Response: The Service mapped the current range of the 
California red-legged frog based on survey results. Wherever a 
watershed was known to support California red-legged frogs, the entire 
watershed was included as being within the species' current range. The 
only watersheds that were not included in their entirety are those in 
the Sierra Nevada where the upper reaches are too high in elevation to 
provide habitat for the California red-legged frog, and portions of 
watersheds located on the Central Valley floor. In the Coast Ranges, 
watersheds lacking information on California red-legged frogs were 
included within the current range of the California red-legged frog 
from Marin County south to Ventura County.
    Over the last 15 years, the petitioners have conducted multiple 
surveys, visiting each survey site a minimum of three times, to 
determine the status of the California red-legged frog throughout its 
entire range. The petitioners rechecked 75 percent of the historic 
sites in the coastal region of the range of the California red-legged 
frog and all suitable habitat within the species historic range in the 
Central Valley and Sierra Nevada foothills including all but one of the 
historic sites. This site was surveyed by another herpetologist, Dave 
Martin (Jennings, pers. comm., 1995). In surveying suitable habitat, 
access to some areas was denied by private landowners. Even so, 
surveyors were able to obtain access to all major drainages within 
their survey area (Jennings, pers. comm., 1995). Many of the surveys 
were conducted between 1986 and 1990, which were considered drought 
years. However, in the majority of cases reasons other than drought 
were considered responsible for the absence of frogs (Jennings, pers. 
comm., 1995). Where drought was thought to be the case, repeat surveys 
were performed in subsequent wet years (Jennings, pers. comm., 1995). 
Approximately half of the sites surveyed were along roadsides and 
easily accessible. The remaining sites were difficult to access, often 
requiring strenuous hikes (Jennings, pers. comm., 1995). Surveying by 
the petitioners and others is ongoing in many portions of the State.
    Surveys conducted by other researchers support the conclusions of 
the petitioners. Extensive surveying has been conducted in years with 
and without drought conditions in Sierran national forests by David 
Martin (University of California, Santa Barbara,, pers. comm., 1994); 
Santa Clara County and the foothills of the western Sierra Nevada 
between Modesto and Fresno by the Coyote Creek Riparian Station (in 
litt., 1993); the Sacramento Valley, San Joaquin Valley and inner Coast 
Ranges by the University of California at Davis (H. Bradley Shaffer, 
University of California, Davis, in litt., 1994); Santa Cruz County by 
the University of California at Santa Cruz (Nauman 1992); Santa Cruz 
and San Mateo counties (Mike Westphal, Coyote Creek Riparian Station, 
1995), and the Point Reyes Peninsula by the National Park Service (Gary 
Fellers, National Biological Service, in litt., 1994).
    As a result of these surveys and additional information received 
during the public comment period following publication of the proposed 
rule, 54 new localities of California red-legged frogs were identified. 
The majority of these sightings, however, are within the current range 
of the California red-legged frog as identified in the proposed rule. 
The exceptions are the discovery of California red-legged frogs in the 
Sierran foothills (Butte County, Pinkard Creek), the Transverse 
mountain range (Los Angeles county near Palmdale), Sulphur Springs 
Creek in Solano County, and Mine Creek in Fresno County; the latter two 
representing minor range extensions to the east. The Service is 
confident that the Central Valley floor, Sierra Nevada foothills, and 
southern California (south of the Tehachapi Mountains) have been 
surveyed sufficiently to draw the conclusion that California red-legged 
frogs have been extirpated or nearly extirpated from these regions. 
These three regions comprise over 70 percent of the California red-
legged frog's historic range.
    Section 4(b)(1)(A) of the Act requires that a listing determination 
be based on the best scientific and commercial data available. The 
Service bases this listing determination on data collected over a 
period of 15 years by the petitioners and numerous other qualified 
herpetologists. All data indicate a downward trend in the range of the 
California red-legged frog and a preponderance of small, fragmented 
aggregations of frogs. The viability of the remaining California red-
legged frog aggregations is threatened by numerous factors which are 
discussed in detail in this rule. The Service maintains, therefore, 
that sufficient data are available to warrant listing the California 
red-legged frog. However, because the Service received significant 
additional information on locations of California red-legged frog 
aggregations within their current range during the comment period, 
listing the taxon as threatened rather than endangered is deemed more 
appropriate.
    Comment: Another commenter stated that the conclusion in the 
proposed rule that 75 percent of the species' remaining range is 
threatened by one or more factors has no basis in scientific fact and 
is not supported by any substantial scientific evidence.
    Service Response: The proposed rule stated that the California red-
legged frog has been extirpated from 75 percent of the historic range 
of the taxon. Because of the inclusion of 54 additional streams or 
drainages known to support California red-legged frogs, the final rule 
has been revised to state that extirpation has occurred in 70 percent 
of the historic range. The commenter misinterpreted the information in 
the proposed rule. The estimate of extirpated range is based on 
information published in the literature and presented to the Service by 
the petitioners and other herpetologists, survey biologists, and 
consultants.
    Comment: One commenter stated that an article in the March 1, 1994, 
San Ramon Valley Times reported that the East Bay Regional Park 
District had not

[[Page 25817]]

surveyed for frogs on its properties. Given that the District comprises 
over 75,000 acres, the commenter believed that this lack of information 
was a significant data gap.
    Service Response: East Bay Regional Park District biologists and 
private consultants in 1990, 1993, and 1994 surveyed an estimated 95 
percent of District properties that could contain California red-legged 
frog habitat (Joseph DiDonato, East Bay Regional Park District, pers. 
comm. and in litt., 1994; Karen Swaim, LSA Associates, Inc., in litt., 
1994). California red-legged frogs were found in 5 of 53 District 
parks. Included in the survey results were 8 streams or drainages not 
previously known to be inhabited by California red-legged frogs.
    Comment: One commenter stated that the information on California 
red-legged frog locations in Alameda County is probably not complete. 
The commenter contended that California red-legged frogs are probably 
not as rare in Alameda County as purported in the proposed rule.
    Service Response: California red-legged frogs are known from 21 
drainages in the county. Many other drainages in the county that have 
been surveyed by the East Bay Regional Park District and LSA 
Associates, Inc. harbor only bullfrogs. Of the 22 counties known to 
support aggregations of California red-legged frogs, Alameda County 
ranks ninth in total number of drainages supporting the taxon. Over 
half of the known frog aggregations in the county, however, are 
threatened by various factors including exotic predators, urban 
development, off-road vehicles, and grazing. While it is possible that 
some California red-legged frog locations have yet to be discovered, 
the Service believes it is unlikely that California red-legged frogs 
inhabit more than the 21 known drainages in Alameda County.
    Comment: One commenter stated that the Service's data on locations 
of California red-legged frogs does not match information contained in 
the California Department of Fish and Game Natural Diversity Database 
(NDDB).
    Service Response: The researchers who petitioned the Service to 
list this species and the Service have reviewed all data available from 
the NDDB regarding locations of California red-legged frogs. The NDDB 
currently contains approximately 122 records of California red-legged 
frogs. The petitioners have determined current and historic range of 
the taxon from 1,205 museum records and 250 records from other sources 
coupled with extensive field checking of records. All locations 
identified in the NDDB prior to 1992 were field checked by the 
petitioners. All new locations identified in the NDDB from 1992 to the 
present have been added to the Service's analysis of the current range 
of the California red-legged frog. These additional records have not 
appreciably extended the currently known range of the taxon.
    Comment: Several commenters noted that the proposed rule indicated 
uncertainty in biology, life cycle, habitat requirements, and predators 
of the California red-legged frog, including identifying where frogs 
overwinter, where post-metamorphic frogs feed, what larvae eat, and 
site specific predators. The commenters believed that listing of the 
taxon was not warranted until these data gaps were filled.
    Service Response: The Service has relied on the best available 
scientific and commercial data in making this listing determination. 
The Service concurs that many aspects of the biology, predator-prey 
interactions, and microhabitat requirements of the California red-
legged frog are not completely understood. This is true for most 
species of wildlife, including common species that have been studied 
extensively. Sufficient knowledge of the biology and habitat 
requirements of the California red-legged frog exists to identify 
suitable habitats for the taxon, and document population sizes, 
threats, and its status over time. It is this latter information along 
with the scientific and commercial information that is used in 
determining whether or not to list a species under section 4(a) of the 
Act. A complete understanding of the biology and microhabitat 
requirements of a listed species are most important in the recovery 
process. However, a significant delay in listing a species due to 
large, long-term biological or ecological research efforts could 
compromise the survival of the California red-legged frog.
    Comment: Several commenters stated that the proposed rule cites 
livestock grazing as a major factor in the decline of the California 
red-legged frog, but fails to offer site-specific examples of habitat 
degradation and ``take'' of the species as a result of grazing. One 
commenter thought that the Service, therefore, could not restrict 
grazing practices in any way if the species is listed.
    Service Response: The proposed rule includes livestock grazing as 
one of many factors affecting the California red-legged frog, and ranks 
it as a contributing factor, rather than as a major factor. No site 
specific studies have been done that document the decline and 
disappearance of California red-legged frogs once grazing is introduced 
into an area. Most evidence on the effects of grazing on the California 
red-legged frog is circumstantial. However, extensive research has been 
done on the effects of livestock grazing on the aquatic environment. As 
stated in the proposed rule, the petitioners found that grazing 
occurred at all historic sites known to support California red-legged 
frogs in the Central Valley hydrologic basin. Combining this 
information with information about the habitat preferences of the 
California red-legged frog leads to the logical conclusion that 
grazing, where it has dramatically altered California red-legged frog 
habitat, has played a role in the decline of this taxon.
    Comment: One commenter stated that the petition to list the 
California red-legged frog relies heavily on personal observations, 
personal communications, and unpublished data. Although the Service is 
required to base listings on the ``best available data'', the commenter 
believed that such information did not meet the definition of 
scientific data because they would be impossible to verify. Three 
commenters recommended that the proposed listing action be halted and a 
comprehensive, unbiased scientific review of the status of the 
California red-legged frog be initiated and published.
    Service Response: The researchers who petitioned the Service to 
list the California red-legged frog are acknowledged experts on this 
taxon as evidenced by numerous peer reviewed publications on the 
subject. The majority of the personal observations cited in the 
petition refer to specific aspects of California red-legged frog 
biology, which is relevant to the species' management, but less 
important in determining species' status. Many of the references to 
unpublished data in the petition refer to distribution and status 
information that had been collected by the petitioners as part of their 
ongoing research to follow the status of the California red-legged 
frog. Much of their status information is supported by surveys 
conducted by numerous other qualified herpetologists. The Service, 
therefore, finds that the data presented by the petitioners are 
credible and have been verified by other experts in the field.
    Comment: Several commenters requested that prior to listing the 
California red-legged frog, the Service quantify impacts to the various 
life stages of the frog caused by storm damage repair, flood control 
efforts, reservoir creation, diking and ditching,

[[Page 25818]]

regular road maintenance, disease, livestock grazing, off-road vehicle 
use, timber harvest, predation by native and non-native predators, 
competition, ultraviolet radiation, water quality, agricultural 
practices, recreation, reproductive interference, drought, wildfires, 
flooding, and natural population fluctuations.
    Service Response: Section 4(a)(1) of the Act requires the Service 
to evaluate threats to the species. The Service is unable to quantify 
how each of the above individual threats has impacted the California 
red-legged frog. Many threats work synergistically to cause population 
declines. Thus, the effect of each threat cannot be quantified 
separately. The above factors are believed to contribute to significant 
population declines. Completing research in all these areas prior to 
listing the California red-legged frog could seriously compromise its 
survival because of lengthy time periods needed to quantify impacts. 
Further research in these areas, however, would aid the Service in 
future recovery actions for this species.
    Comment: One commenter recommended that the Service delineate the 
current range and habitat locations of the California red-legged frog 
in San Joaquin County prior to listing.
    Service Response: The Service has delineated the current range and 
specific habitat locations of California red-legged frogs in San 
Joaquin County. Two locations of the California red-legged frog occur 
in San Joaquin County, both in western portions of the county. The 
distribution map for the California red-legged frog includes all 
portions of western San Joaquin County that lie on the east slope of 
the coast range, west of Highway 580.
    Comment: One commenter recommended that the Service quantify 
California red-legged frog population numbers in lotic and lentic 
habitat and establish management and recovery programs for each habitat 
type prior to listing the taxon.
    Service Response: A recovery plan will be prepared for the 
California red-legged frog after the taxon is listed. Completion of the 
above recommended research would be most appropriate during the 
recovery process for the California red-legged frog.

Issue 2: Causes for California Red-Legged Frog Decline

    Comment: Several commenters suggested that ultraviolet-B (UV-B) 
radiation or estrogen mimics, which have been implicated in the current 
observed worldwide decline in amphibians, may be significant causes of 
observed declines in the range and numbers of California red-legged 
frogs.
    Service Response: The Service has reviewed the paper by Blaustein 
et al. (1994) regarding the possible effect of UV-B radiation on the 
eggs of three amphibian species, the Pacific treefrog (Pseudacris 
regilla), western toad (Bufo boreas), and Cascade frog (Rana cascadae). 
Our review focused on results reported for the Cascade frog, because 
this species is most closely related to the California red-legged frog. 
Results of tests on Cascade frog eggs from two sites showed mixed 
results. One site showed that hatching success of R. cascadae was 
greater under sunlight lacking UV-B than under unfiltered sunlight. At 
the second site, however, the hatching success under UV-B blocking 
filters was not significantly different from success under unfiltered 
sunlight. Thus, these data do not present sufficient evidence of a 
correlation between UV-B radiation and hatching success in the related 
Cascade frog.
    Because UV-B radiation would have greater adverse effects at higher 
elevations, the Cascade frog, which is a higher elevation species than 
the California red-legged frog, would be expected to be more severely 
affected by UV-B radiation, if indeed this is an important factor. 
Also, because the California red-legged frog attaches its egg masses to 
aquatic vegetation and prefers aquatic habitats with overhanging 
vegetation, the effects of UV-B radiation would be expected to be less 
than for the Cascade frog, whose eggs are typically laid in shallow 
open water (Nussbaum et al. 1983). In addition, the majority of the 
observed decline in the California red-legged frog occurred prior to 
the late 1970's, which is when noticeable declines in amphibian species 
began in western North America (M. Jennings, pers. comm, 1994).
    A number of recent studies address certain contaminants that 
disrupt biological processes by mimicking the effects of naturally 
produced hormones, such as the female hormone estrogen (Raloff 1994). 
This phenomenon has been implicated in the recent worldwide decline in 
amphibians. Several studies have been done on reptiles, including the 
American alligator (Alligator mississippiensis) and red-eared slider 
turtle (Pseudemys scripta elegans). To our knowledge, no studies have 
been done on amphibians. The potential effects of estrogen mimics on 
California red-legged frogs are unknown. In addition, the majority of 
the observed decline in the California red-legged frog occurred prior 
to the late 1970's, which is when noticeable declines in amphibian 
species began in western North America (M. Jennings, pers. comm, 1994).
    Comment: Several commenters stated that evidence suggesting 
mosquitofish (Gambusia affinis) are significant predators of California 
red-legged frog larvae is not strong. The commenters stated that 
infrequent co-occurrence of fish and frogs does not explain potential 
causation. Other factors may be involved in population decline 
including microhabitat features of wetlands, which cannot be 
successfully duplicated in a laboratory setting. Also in a natural 
setting, the vulnerable stage for California red-legged frog tadpoles 
(February through April) normally does not coincide with the time of 
year when mosquitofish numbers are high. Microhabitat usage may not 
overlap. The commenters pointed out that there are sites where 
mosquitofish and California red-legged frogs coexist. One commenter 
objected to the mosquitofish being included as a verified predator of 
California red-legged frogs and especially as an organism more harmful 
than introduced centrarchid fishes or bullfrogs.
    Service Response: The Service is aware of only one study that has 
indicated that in laboratory settings mosquitofish prey on the larvae 
of California red-legged frogs (Schmieder and Nauman 1994). However, 
there is a strong correlation between the absence of California red-
legged frogs and the presence of mosquitofish in the field. The Service 
is aware of several sites where mosquitofish and California red-legged 
frogs are currently coexisting. This evidence suggests that the 
relationship between mosquitofish and California red-legged frogs is 
complex. Additional research clearly is needed to more fully understand 
how these two species interact. The final rule has been revised to 
reflect current knowledge on this issue. The Service cannot determine 
whether mosquitofish are harmful to California red-legged frogs.
    Comment: Several commenters disagreed that mosquitofish could be 
significant predators of California red-legged frogs. They cited 
observations in mosquitofish ponds of mosquitofish numbers decreasing 
as a result of infestations by bullfrogs. These commenters noted that 
no predation of bullfrog tadpoles by mosquitofish was observed.
    Service Response: Mosquitofish would not be expected to prey on 
larval bullfrogs because of the apparent olfactory rejection 
(unpalatability) of bullfrog larvae by predatory fish (Kruse and 
Francis 1977). California red-legged

[[Page 25819]]

frogs lack this olfactory rejection effect, and, therefore, cannot be 
compared to bullfrogs (Schmieder and Nauman 1994).
    Comment: One commenter pointed out that widespread, large scale use 
of mosquitofish in California began in the mid to late 1970's, and 
therefore, could not be responsible for the extirpation of California 
red-legged frogs from the Central Valley floor because frogs were 
extirpated from this region before 1960.
    Service Response: The Service concurs that mosquitofish were not a 
major factor in the decline and disappearance of California red-legged 
frogs from the Central Valley floor. The proposed and final rules point 
to overharvest combined with the loss of over 3,800,000 acres of 
wetlands as the major reasons for extirpation of California red-legged 
frogs from the valley floor (Frayer, et al. 1989). However, significant 
introductions of mosquitofish began in the Central Valley as early as 
1922 (Moyle 1976). Thus it is possible that mosquitofish played a role 
in the decline of California red-legged frogs on the Central Valley 
floor.
    Comment: Two commenters stated that mosquitofish are not 
significant predators of California red-legged frogs because the two 
species coexist in wetlands in Shasta and Colusa counties.
    Service Response: California red-legged frogs were extirpated from 
Shasta and Colusa counties before 1960 (Jennings et al. 1992).
    Comment: Several commenters provided more specific or additional 
information on threats to California red-legged frogs within their 
current range. Several commenters provided information regarding 
potential threats, including road kills, current harvesting of 
California red-legged frogs for food, construction activities, and poor 
management of flood control basins.
    Service Response: These comments have been noted and included in 
this final rule.
    Comment: One commenter stated that massive predation by introduced 
predators, not grazing, is in large part responsible for any observed 
population declines in the California red-legged frog. Similarly, 
another commenter stated that the decline and disappearance of 
California red-legged frogs in the foothill portions of Madera, Fresno, 
and Mariposa counties were due to dispersal of bullfrogs into stock 
ponds, and not due to grazing. The commenter stated that California 
red-legged frogs coexisted with grazing until about 1940, when 
bullfrogs were introduced into the San Joaquin Valley.
    Service Response: Of the identified threats facing the California 
red-legged frog, introduced predators, including bullfrogs, are 
considered to be a significant and widespread threat. Over 50 percent 
of streams and drainages inhabited by California red-legged frogs are 
known to support bullfrogs or other exotic predators in some portion of 
that drainage. Grazing, however, can threaten the California red-legged 
frog where grazing pressure results in dramatic changes in riparian and 
wetland habitat. As discussed in this final rule, California red-legged 
frogs generally prefer densely-shaded wetland habitats, whereas 
bullfrogs prefer more open wetland habitats. Overgrazing in riparian 
areas, therefore, exacerbates the threat of bullfrog expansion by 
creating habitat bullfrogs prefer.
    Comment: One commenter stated that profitable livestock operations 
and high quality riparian habitat areas are not mutually exclusive. The 
commenter points to Point Reyes National Seashore as an example of 
where cattle grazing and California red-legged frogs successfully 
coexist. The commenter stressed that livestock grazing is the only 
economic activity in the region that provides large contiguous areas of 
open space.
    Service Response: The Service concurs that properly managed 
livestock grazing can be compatible with preservation of California 
red-legged frog populations. California red-legged frogs and cattle 
grazing are able to coexist at Point Reyes National Seashore because 
the National Park Service maintains tight control over grazing pressure 
(Gary Fellers, National Biological Service, pers. comm., 1994). The 
Service acknowledges that preservation and proper management of open 
space, especially in riparian areas, is a fundamental requirement in 
the survival and recovery of the California red-legged frog.
    Comment: One commenter stated that the single most devastating 
change in wildlife habitat in California in the last 200 years has been 
urbanization. The commenter thought that the proposed rule had not 
given this factor proper recognition, but instead condemned activities 
such as livestock grazing.
    Service Response: The proposed rule and this final rule do not 
single out livestock grazing as the greatest threat to the California 
red-legged frog, but instead discusses all factors known or likely to 
threaten California red-legged frog populations. The proposed and final 
rules list numerous proposed developments that threaten remaining 
populations of California red-legged frogs. The Service believes 
urbanization, as well as agriculture, have caused substantial changes 
in wildlife habitat in California. This is especially the case in the 
Central Valley, which historically was the stronghold of the California 
red-legged frog.
    Comment: Several commenters stated that climatic conditions (i.e., 
drought and above average rainfall events) were more to blame for 
California red-legged frog declines than human activities, including 
timber harvest and historic commercial harvest of the California red-
legged frog itself. One commenter noted that dramatic declines in 
historic frog harvest information could indicate that the species is 
subject to wide variation in population numbers due to climatic 
conditions rather than an indication of overharvest. The commenter 
requested that an historical survey of the variations in population 
numbers due to climatic changes be undertaken prior to publication of a 
final rule.
    Service Response: The rule includes a discussion of natural 
factors, such as drought and heavy rainfall events, that are known to 
adversely affect California red-legged frog populations. It is 
difficult to separate the effects of natural events from human 
activities when attempting to determine the cause for a population's 
decline in a particular area. A single factor is seldom the cause of 
the decline of a species. Many of the factors discussed in the proposed 
rule and this final rule work synergistically. Regardless of which 
factors resulted in historic population declines, California red-legged 
frog populations in the Central Valley and Sierra Nevada, in 
particular, could not rebound from this decline because at the same 
time their wetland and riparian habitat was being converted to 
agricultural land and urban areas.
    Populations of most species are cyclic in nature, responding to 
such natural factors as weather events, disease, and predation. Natural 
events, however, including long-term drought or extreme rainfall, have 
less of a negative effect overall on a species when that species is 
widely and continuously distributed. Where populations are small, 
fragmented, or isolated by various human-related factors including 
habitat loss, water development, and water diversion, these populations 
are more vulnerable to extirpation by stochastic or random events and 
cumulative effects.
    It is likely that over time, California red-legged frogs 
experienced wide variations in population size as a result of climatic 
events. A historical survey dating back to the early 1900's focusing on 
the variation in frog population

[[Page 25820]]

numbers due to climatic changes is not possible because no range wide 
population information was collected on the California red-legged frog 
dating back that far. If such data existed, conclusions drawn from such 
an historical survey would be tenuous. The many adverse human factors 
that have contributed to California red-legged frog population declines 
since 1900 would cloud any analysis of the effects of drought or high 
rainfall events.
    Comment: One commenter disagreed with the conclusion that pre-1900 
overharvesting of the California red-legged frog in the Central Valley 
led to their decline. The commenter stated that other known historical 
factors were not cited in the proposed rule.
    Service Response: No studies were conducted in the late 1800's or 
early 1900's documenting the cause or causes of declines in California 
red-legged frog populations in the Central Valley. Extremely high 
numbers of California red-legged frogs reported in the San Francisco 
markets followed by a collapse of the market around the turn of the 
century strongly suggests that commercial harvesting had a significant 
effect on California red-legged frog numbers. The Central Valley, and 
particularly the San Joaquin Valley, were reported at the time to be 
prime habitat for the California red-legged frog. The proposed rule and 
this final rule reported all known historical factors that may have 
contributed to the decline of California red-legged frogs in the 
Central Valley. Overharvesting was certainly not the only factor 
impacting California red-legged frog populations. Conversion of over 
3,800,000 acres of wetland and riparian habitats in the Central Valley 
to agricultural land and urban areas began during the same period, 
resulting in the elimination of California red-legged frogs from the 
valley floor before 1960.
    Comment: Several commenters stated that many of the urban 
development projects referred to in the proposed rule in the Central 
Coast region may or may not be constructed during the next 5 or 10 
years.
    Service Response: The Service recognizes that all projects proposed 
are not necessarily completed. This may be due to lack of proper 
permits necessary for construction, or interruption of planning 
efforts. The fact that projects have been proposed presents a future 
threat to California red-legged frog aggregations in the central coast 
region, especially if these projects result in direct or indirect 
riparian habitat degradation.
    Comment: One commenter stated the proposed rule incorrectly 
includes the Cambria Meadows drainage as an area where California red-
legged frog habitat has been directly degraded through stream 
reductions to accommodate new urban growth.
    Service Response: This final rule states that proposed urban and/or 
recreational development could degrade or eliminate California red-
legged frog habitat in Cambria Meadows Creek.
    Comment: One commenter thought that support of the proposed listing 
appeared to rely heavily on conditions reported for the north coast of 
San Luis Obispo County.
    Service Response: Neither the proposed rule nor this final rule 
rely heavily on conditions reported for the north coast of San Luis 
Obispo County in determining the need to list the California red-legged 
frog. San Luis Obispo County contains the third highest number of 
drainages known to support California red-legged frogs. Although 
California red-legged frog aggregations in streams in the county are 
threatened by a variety of factors, many other counties have comparable 
threats that are reported in the proposed and final rule.
    Comment: Several commenters were concerned about the accuracy of 
the conclusions drawn by Rathbun et al. (1991) as cited in the proposed 
rule regarding the combined effects of water extraction and drought on 
populations of California red-legged frogs in lower Santa Rosa Creek. 
Numerous commenters presented data both to support and refute the 
hypothesis that water extractions from Santa Rosa Creek have 
significantly changed its hydrology.
    Service Response: The Service recognizes that controversy exists 
regarding the environmental effects of water extraction from Santa Rosa 
Creek. The information and data presented by the many commenters on 
this subject will be thoroughly reviewed by Service field biologists 
during recovery planning efforts and when consulting on any proposed 
projects that could adversely affect California red-legged frogs in 
Santa Rosa Creek.
    Ground water and surface water supplies in Santa Rosa Creek are 
finite. Unchecked water extraction may exceed input and significantly 
reduce the availability of riparian and aquatic habitat for California 
red-legged frogs in the future. Drought accentuates the effect, and if 
not considered in water planning, overallocation of stream flows and 
overdraft of groundwater resources combined with long-term drought 
could result in permanent elimination of California red-legged frogs 
from all or a large part of the drainage.
    Comment: Several commenters pointed out that although California 
red-legged frogs were absent from lower Santa Rosa Creek during the 
drought (Rathbun et al. 1991), red-legged frogs have been sighted in 
recent years in the lower reaches of the creek, presumably because of 
the above average rainfall in the winter of 1992-1993. California red-
legged frogs, which were known to inhabit upper reaches of the creek 
during the drought years, were presumed to have traveled downstream to 
reoccupy former habitat. One commenter suggested that the Service 
should study an entire watershed prior to concluding that the 
California red-legged frog is threatened in that watershed.
    Service Response: The Service is aware that California red-legged 
frogs occur in the upper reaches of Santa Rosa Creek. Santa Rosa Creek 
is one of 32 drainages in San Luis Obispo County known to provide 
habitat for the California red-legged frog. Neither the Service nor 
Rathbun et al. (1991) have concluded that California red-legged frogs 
have disappeared from Santa Rosa Creek. Rathbun et al. (1991) refers 
only to conditions in the lower portions of the creek and lagoon.
    The Service recognizes that the California red-legged frog is 
capable of repopulating former habitat when rainfall returns. However, 
other factors, including overallocation of water, may exacerbate the 
effects of drought through loss of riparian habitat or increased 
salinity in coastal lagoons. Where appropriate riparian or wetland 
habitat is degraded over the long-term by these hydrologic 
modifications, repopulation by California red-legged frogs in altered 
portions of the drainage is not possible regardless of whether red-
legged frogs occur in upstream reaches. As portions of the drainage 
become unsuitable habitat for California red-legged frogs, isolated 
aggregations of frogs become more susceptible to stochastic extinction. 
The Service is not basing this listing determination on the status of 
the California red-legged frog in any one specific watershed, but 
rather on the continuing population decline and threats to the 
remainder of its range.
    Comment: One commenter noted that California red-legged frogs 
persist in upstream portions of Carmel River despite the fact that 
bullfrogs are found in the lower river and two reservoirs. The 
commenter felt that this evidence refuted the assertion that California 
red-legged frog populations usually disappear from a drainage within 5 
years after a reservoir is built.

[[Page 25821]]

    Service Response: The proposed rule and this final rule state that 
California red-legged frogs generally are extirpated from downstream 
portions of a drainage 1 to 5 years after filling of a reservoir. Hayes 
and Jennings (1988), which is cited as the source of this information, 
does not present this cause and effect relationship as an absolute. The 
authors state that this relationship depends on the size of the 
drainage. In larger drainages, isolated populations can persist 
upstream. This final rule has been revised to clarify this point.
    Comment: One commenter thought that too much emphasis was given to 
the negative impacts of salinity levels in coastal lagoons. Natural 
overwash of salt water into coastal lagoons makes these areas 
unreliable habitat for California red-legged frogs.
    Service Response: The Service acknowledges that coastal lagoons 
provide unreliable habitat for California red-legged frogs because of 
natural salinity changes caused by wave overwash. However, large 
populations of California red-legged frogs do occur in coastal lagoons, 
with Pescadero Marsh supporting one of the largest remaining 
populations. Therefore, the larger lagoon systems should not be 
discounted. Overallocation of stream water resources intensifies the 
effect of drought on coastal lagoon populations, which over the long-
term could result in changes in lagoon vegetation and hydrology that 
are unfavorable to California red-legged frogs.
    Comment: One commenter suggested that competition with tree frogs 
and foothill yellow-legged frogs (Rana boylii) may be a contributing 
factor in the decline of California red-legged frog.
    Service Response: No evidence exists in the literature to support 
the theory that competition between California red-legged frogs and 
Pacific tree frogs or foothill yellow-legged frogs resulted in 
California red-legged frog declines.

Issue 3: Economic and Environmental Effects of Listing

    Comment: Several commenters stated that listing of the California 
red-legged frog may act to limit or curtail existing uses of private 
property, and therefore, a takings implication assessment should be 
made prior to taking any final action.
    Service Response: Regarding Executive Order 12630, Governmental 
Actions and Interference with Constitutionally Protected Property 
Rights, the Attorney General has issued guidelines to the Department of 
the Interior (Department) on implementation of the Executive Order. 
Under these guidelines, a special rule applies when an agency within 
the Department is required by law to act without exercising its usual 
discretion--that is, to act solely upon specified criteria that leave 
the agency no discretion.
    In this context, the Service might be subject to legal challenge if 
it considered or acted upon economic data. In these cases, the Attorney 
General's guidelines state that Takings Implications Assessments (TIAs) 
shall be prepared after, rather than before, the agency makes the 
decision upon which its discretion is restricted. The purpose of TIAs 
in these special circumstances is to inform policy makers of areas 
where unavoidable taking exposures exist. Such TIAs shall not be 
considered in the making of administrative decisions that must, by law, 
be made without regard to their economic impact. In enacting the Act, 
Congress required the Department to list species based solely upon 
scientific and commercial data indicating whether or not they are in 
danger of extinction. The Act does not allow the Service to withhold a 
listing based on concerns regarding economic impact. The provisions of 
the guidelines relating to nondiscretionary actions clearly are 
applicable to the determination of threatened status for the California 
red-legged frog.
    Comment: Several commenters expressed concern about an adverse 
effect of listing the California red-legged frog on the economy. 
Another commenter stated that the economic impact of listing the 
California red-legged frog would be devastating to an already sluggish 
State economy.
    Service Response: Under section 4(b)(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'' that listing 
decisions are ``* * * based solely on biological criteria and to 
prevent nonbiological 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 * * *'' 
Id. at 20. Because the Service is specifically precluded from 
considering economic impacts, either positive or negative, in a final 
decision on a proposed listing, the Service need not evaluate or 
consider the economic impacts of listing this species.
    Comment: One commenter suggested that the researchers who 
petitioned the Service to list this species were using the Endangered 
Species Act as a method of furthering their personal agenda to remove 
livestock from public and private rangeland.
    Service Response: The Service is unaware that the researchers who 
petitioned the Service to list the California red-legged frog have a 
personal agenda to remove livestock from public and private rangeland. 
Management of livestock on rangelands is one of many possible 
alternatives available to address adverse effects of grazing on 
California red-legged frog populations. For example, minor alterations 
in management practices and fencing of key riparian areas are two 
alternatives that preserve grazing opportunities while protecting 
California red-legged frogs.
    Comment: Numerous commenters stated that the Service should 
consider the human health implications of eliminating the use of 
mosquitofish, draining of wetlands, and insecticides to control 
mosquitos.
    Service Response: California red-legged frogs require still or 
slow-moving water with dense emergent and overhanging riparian 
vegetation for survival. Sites with these habitat attributes are often 
at great distances from urban areas and are not regularly stocked with 
mosquitofish or otherwise managed to control mosquitos. Therefore, at 
the majority of remaining sites inhabited by California red-legged 
frogs, mosquito control is not likely to be an issue. Where mosquitos 
are an issue, other biological control methods are available and may be 
more appropriate in California red-legged frog habitat. These methods 
include application of several species of bacteria (Bacillus sp.), and 
more recently, application of a fungus (Lagenidium giganteum), which 
apparently attacks and kills only mosquitos. The Service is willing to 
work with mosquito and vector control districts to minimize conflicts 
between public health and the California red-legged frog.
    The Service concludes that listing the California red-legged frog 
as a threatened species is not likely to hinder efforts of any Mosquito 
and Vector Control Districts to control mosquitos in California.
    Comment: One commenter stated that cessation or curtailment of 
water releases from reservoirs to accommodate the California red-legged 
frog could adversely impact other species, including several species of 
anadromous fish.
    Service Response: If changes in reservoir release schedules are 
needed, the Service, in conjunction with the California Department of 
Fish and Game, will consider the needs of all

[[Page 25822]]

species that could be affected as recommendations are made.

Issue 4: Designation of Critical Habitat

    Comment: Several commenters recommended that the Service designate 
critical habitat for the California red-legged frog so that it would be 
easier for interested parties to locate known and additional 
populations of the species, and thus, contribute to an accurate 
determination of the need for protection. One commenter recommended 
designation of critical habitat as an additional way to protect 
California red-legged frogs on private land. One commenter stated that 
an economic analysis should be conducted prior to designating critical 
habitat.
    Service Response: The Service has determined that designation of 
critical habitat for the California red-legged frog would be more 
detrimental than beneficial to the species. Concern for the potential 
``take'' of the species (as defined in the Act) through acts of 
vandalism has been expressed by the petitioners and other parties (see 
further discussion in ``Summary of Factors Affecting the Species'' 
(Factor B) and ``Critical Habitat'' sections, below). Revealing of the 
precise locations of California red-legged frog habitat, as required 
through critical habitat designation, would make the species more 
vulnerable to vandalism and unauthorized takings. The Service has 
determined that designation of critical habitat is not prudent for the 
California red-legged frog, therefore, preparation of an economic 
analysis is not required. However, the Service has identified recovery 
units for the species.
    Designation of critical habitat would not necessarily provide 
additional protection for California red-legged frog aggregations on 
private land. Critical habitat legally applies only to Federal lands or 
activities on non-federal lands regulated, sponsored, or funded by a 
Federal agency. For example, designation of critical habitat on private 
grazing lands would not provide added protection against the impacts of 
grazing on California red-legged frog habitat because there is no 
federal nexus. Conversely, activities on private lands that are 
authorized, funded or carried out by a Federal agency, such as permit 
actions authorized under section 404 of the Clean Water Act, would 
require consultation with the Service if the activity was expected to 
adversely affect a Federally listed endangered or threatened species. 
This would apply regardless of whether critical habitat was designated 
or not.

Issue 5: National Environmental Policy Act

    Comment: Several commenters stated that the proposal to list the 
California red-legged frog requires preparation of an Environmental 
Impact Statement (EIS) under the National Environmental Policy Act 
(NEPA). Another commenter stated that an Environmental Assessment may 
be necessary to determine the effects of the listing on other native 
species, disease-producing organisms, and humans.
    Service Response: The Service need not prepare environmental 
assessments or environmental impacts statements pursuant to the 
National Environmental Policy Act (NEPA) for reasons outlined in the 
Federal Register on October 25, 1983 (48 FR 49244). Basically the 
listing of a species is exempt as a matter of law from NEPA review. 
Listing decisions are based on biological, not sociological or economic 
considerations. This view was upheld in the court case Pacific Legal 
Foundation v. Andrus, 657 F. 2d 829 (1981).

Issue 6: Alternate Listing Status Recommended

    Comment: Several commenters recommended that the California red-
legged frog be listed as a threatened rather than an endangered species 
in various watersheds because measures are already being taken through 
Federal, State, and/or private efforts to protect California red-legged 
frog habitat, or because the numbers of California red-legged frogs in 
these watersheds are greater and the threats less than in other 
watersheds within the California red-legged frog's distribution. One 
commenter provided examples of specific streams including--(1) Sespe 
Creek, where 31 miles within the Forest Service's Sespe Wilderness Area 
have been designated as Wild and Scenic, and a portion of Sespe Creek 
is included within the Sespe Condor Sanctuary; and (2) Piru Creek, 
where flow releases have been modified to protect the Arroyo 
southwestern toad (Bufo microscaphus californicus), an endangered 
species.
    Service Response: Additional information received during the public 
comment period regarding new locations of California red-legged frogs 
confirmed that the taxon is more widespread within its current range 
than previously thought. The existence of 54 new drainage localities, 
and some drainages with non-imminent threats, indicates that listing as 
a threatened rather than an endangered species is presently more 
appropriate for the California red-legged frog. The species is not now 
in danger of extinction throughout all or a significant portion of its 
range in the near future, however, evidence does indicate that it may 
become endangered.
    The Service acknowledges that a portion of Sespe Creek is 
designated as ``Wild and Scenic'' under the Wild and Scenic River Act, 
16 U.S.C. 1271 et seq., and that activities such as reservoir 
development or channelization, may be prohibited in this area. The 
Service also recognizes that the portion of the creek within the Sespe 
Condor Sanctuary may be protected in certain ways. However, designation 
as such does not eliminate all potential threats to the California red-
legged frog. For example, designation as Wild and Scenic does not 
protect against invasion of bullfrogs or other exotic predators, which 
are known to occur in other portions of Sespe Creek. Planned reservoir 
development downstream of the Wild and Scenic portion of Sespe Creek 
increases the likelihood that bullfrogs and introduced fishes could 
disperse into upstream protected portions of the creek. Also, the Wild 
and Scenic designation does not eliminate recreational uses of the 
creek, including such activities as fishing, camping, mountain biking, 
and horseback riding. The Sespe Creek portion of the Sespe Condor 
Sanctuary is not closed to recreational use by the public.
    On Piru Creek, studies suggest that modified water releases from 
Lake Pyramid over the last four years have resulted in increased Arroyo 
southwestern toad populations (Cat Brown, Fish and Wildlife Service, 
pers. comm., 1994). No research has been conducted to document the 
effect of these flow releases on California red-legged frogs.
    Although the status of the California red-legged frog is not 
uniform throughout its range, the overall picture is one of a 
threatened species. Recovery planning and consultations under section 7 
of the Act will take into account the status of the California red-
legged frog within recovery units of its range (see ``Available 
Conservation Measures'' section).
    Comment: One commenter from Santa Barbara County recommended that 
the California red-legged frog be listed as a threatened species 
because the current range of the California red-legged frog is broad 
and includes most of its historic range. Another commenter thought that 
the current range of the California red-legged frog, which is 300 miles 
north to south, did not fit the definition of an endangered species.
    Service Response: Section 3(20) of the Act defines a threatened 
species as one which is likely to become an

[[Page 25823]]

endangered species within the foreseeable future throughout all or a 
significant portion of its range. Although the current range of the 
California red-legged frog encompasses less than 30 percent of its 
historic distribution, new information received during the public 
comment period suggests that California red-legged frogs are more 
widespread within their current range than previously believed. For 
this reason and the fact that 17 percent of the remaining drainages 
occupied by frogs are not known to be imminently threatened, the 
Service has concluded that the California red-legged frog more 
appropriately meets the definition of a threatened species.
    Comment: Several commenters requested that California red-legged 
frogs in specific drainages of the Central Coast or the entire Central 
Coast be exempt from endangered species status because California red-
legged frogs seem to be adequately managed in this area, have not shown 
population declines, or have fewer exotic species problems.
    Service Response: Section 3(16) the Act defines the term 
``species'' to include any subspecies of fish, wildlife, or plants, and 
any distinct population segment of any species of vertebrate fish or 
wildlife that interbreeds when mature. California red-legged frog 
aggregations in certain drainages of the central coast of California or 
in the entire central coast region do not constitute distinct 
vertebrate population segments. The Service cannot exclude these areas 
and intends to list the taxon as threatened throughout its range.

Issue 7: Research and Education Needs

    Comment: Several commenters recommended the following research 
topics be explored in relation to conservation of the California red-
legged frog: (1) Seasonal utilization of patchy habitats for breeding, 
refugia and estivation; (2) migration timing; (3) estivation timing; 
(4) surveying methodology in marginal habitat; and (5) the effects of 
pesticide and herbicide runoff.
    Service Response: These comments have been noted and will be 
considered during preparation of a recovery plan for the California 
red-legged frog.
    Comment: One commenter committed to assisting the Service with 
cooperative research on mosquitofish/California red-legged frog 
interactions.
    Service Response: The Service concurs fully with the need for 
further research in this area and acknowledges the commenter's 
commitment to this effort.
    Comment: One commenter asked if a program could be developed that 
would allow for variable treatment/management of California red-legged 
frog habitat that was found to produce significant numbers of 
mosquitoes.
    Service Response: Because California red-legged frog habitat is 
variable, it is likely that management programs for mosquitoes will 
also be variable and depend on the situation under review. Research 
into the effects of various methods of mosquito control on California 
red-legged frogs should aid the Service in any recovery planning 
undertaken for the taxon.
    Comment: One commenter recommended a number of ways to educate the 
general public regarding listed species and elicit their support, 
including publishing information in trade journals, posting signs at 
storm drains to discourage dumping of contaminants, reevaluating the 
need for channelized creeks, educating the public regarding the effects 
of bullfrogs on native amphibians, teaching classes in grade schools, 
starting riparian revegetation projects, and encouraging participation 
of landowners by providing incentives.
    Service Response: The comments have been noted. The Service 
welcomes recommendations from the public on how to further the purposes 
of the Endangered Species Act. The Service has implemented many of 
these recommendations in regard to other listed species and will give 
them due consideration in public education programs related to recovery 
of the California red-legged frog.

Issue 8: Systematic Relationships Between Red-legged Frog 
Subspecies

    Comment: Several commenters questioned the Service's exclusion of 
the intergrade zone between the northern red-legged frog (Rana aurora 
aurora) and the California red-legged frog (Rana aurora draytonii) in 
northwestern California. They argued that this segment of the 
subspecies' range does not constitute a distinct population segment 
and, therefore, cannot be excluded from the listing package. One 
commenter suggested that the Service excluded this segment of the 
subspecies' range to make the subspecies distribution seem smaller and 
in greater need of protection.
    Another commenter suggested that the two subspecies are actually 
different populations of the same species displaying morphological 
differences due to climatic and habitat variations. In this case, the 
population numbers and distribution of the species would be much 
greater and the need for listing nonexistent.
    Service Response: The California red-legged frog is a recognized 
subspecies of the red-legged frog (Storer 1925, Cochran 1961, Stebbins 
1985). As discussed in the background section of this rule, the range 
of the California red-legged frog is the vicinity of Point Reyes 
National Seashore, Marin County, California, coastally and from the 
vicinity of Redding, Shasta County, California, inland southward to 
northwestern Baja California, Mexico (Jennings and Hayes 1985, Hayes 
and Krempels 1986). Red-legged frogs found in the intergrade zone from 
northern Marin County to southern Del Norte County are not considered a 
population segment of the California red-legged frog. At this time, 
researchers have not assigned the intergrade zone to either subspecies.
    Among other differences, red-legged frogs within the intergrade 
zone are distinct morphologically from either subspecies of Rana 
aurora. The California red-legged frog possesses paired vocal sacs 
whereas the northern red-legged frog lacks vocal sacs. Most red-legged 
frogs found in the intergrade zone from northern Marin County to 
southern Del Norte County possess only one vocal sac. Based on this 
pronounced morphological difference in red-legged frogs in the 
intergrade zone, some researchers have concluded that the California 
and northern red-legged frogs may be two distinct species, and that the 
intergrade zone represents a zone of secondary contact or hybridization 
between the two species (Hayes and Krempels 1986). Genetic research has 
been proposed to clarify systematic relationships (i.e., to determine 
if R. a. aurora and R. a. draytonii should be classified as two species 
or should remain as subspecies) and allow a more precise identification 
of the northern limits of the geographic distribution of the California 
red-legged frog (Jennings et al. 1992). In addition, habitat within the 
majority of the intergrade zone (moist evergreen/hardwood forest) is 
more indicative of habitat preferred by the northern red-legged frog. 
Thus, if the Service were to assign the intergrade zone to either 
subspecies based on habitat preference alone, the intergrade zone would 
be more appropriately placed within the range of the northern red-
legged frog.
    Comment: One commenter noted that the California Academy of 
Sciences has 66 specimens identified as Rana aurora draytonii that were 
collected from Redwood National Park in Humboldt County between 1911 
and 1940. The commenter stated that more specific identification of 
herpetological subspecies would be needed to

[[Page 25824]]

determine the boundary of California red-legged frogs as far north as 
Del Norte County.
    Service Response: The specimens referred to by the commenter were 
identified as R. a. draytonii in the 1940's based on size, skin 
characteristics, and prominence of dorsolateral folds as described by 
Camp (1917). More recent research (see Hayes and Miyamoto 1984, Hayes 
and Krempels 1986), has identified vocal sac condition as a distinct 
morphological characteristic differentiating the two subspecies. Using 
these new findings, the researchers who petitioned the Service to list 
the species have reviewed the specimens in question and found that they 
should have been identified as intergrades between R. a. aurora and R. 
a. draytonii. As discussed above, research currently underway is 
designed to further refine the northern boundary of the California 
subspecies' range.
    Comment: Another commenter suggested that the listing package 
should only consider red-legged frogs at the species level, and, 
therefore, if red-legged frogs were temporarily eliminated from some 
part of their range in California, frogs from other areas would 
recolonize suitable habitat.
    Service Response: Section 3(15) of the Endangered Species Act 
defines a species to include ``any subspecies of fish or wildlife or 
plants* * *''. Therefore, listing of a recognized subspecies is 
authorized in the Act.
    The ability of red-legged frogs to migrate from one drainage to 
another would be dependent upon the distance, topography and habitat 
type through which the frogs would be required to migrate. Considering 
the Mediterranean climate in California, with its seasonal dryness, it 
is unlikely that red-legged frogs could very successfully migrate long 
distances to repopulate formerly occupied habitat.

Issue 9: Existing Regulatory Mechanisms

    Comment: Several commenters believed that existing regulations 
(i.e., Clean Water Act, California Environmental Quality Act) and 
monitoring by several Federal agencies are providing adequate 
protection for the California red-legged frog, and, therefore, listing 
is not needed.
    Service Response: The Service believes that existing regulatory 
mechanisms do not currently provide adequate protection for the 
California red-legged frog. A discussion of existing regulations can be 
found below in Factor D of the ``Summary of Factors Affecting the 
Species'' section and the ``Available Conservation Measures'' section.

Issue 10: Miscellaneous

    Comment: One commenter pointed out that the Cambria Community 
Services District acts responsibly in protecting Santa Rosa and San 
Simeon Creek, including reductions in pumping during drought periods, 
promoting retrofit programs to reduce water usage, research into 
desalination alternatives and reverse osmosis treatment of wastewater, 
and approval of riparian habitat improvements.
    Service Response: The Service acknowledges the District's efforts 
to protect stream flows and the natural environment of Santa Rosa and 
San Simeon Creeks. However, the Service has identified threats in these 
drainages and other drainages as well.
    Comment: One commenter indicated that mosquito abatement districts 
have modified their mosquitofish planning protocol to carefully 
consider the introduction of mosquitofish in areas inhabited by listed 
species.
    Service Response: The Service acknowledges the program 
modifications made by many mosquito abatement districts to protect 
listed species and their habitat.

Summary of Factors Affecting the Species

    After a thorough review and consideration of all information 
available, the Service has determined that the California red-legged 
frog should be listed as a threatened species. Procedures found at 
section 4 of the Act (16 U.S.C. 1533 et seq.) and regulations (50 CFR 
Part 424) promulgated to implement the listing provisions of the Act 
were followed. A species may be determined to be an endangered or 
threatened species due to one or more of the five factors described in 
section 4(a)(1). These factors and their application to the California 
red-legged frog (Rana aurora draytonii) are as follows:
    A. The present or threatened destruction, modification, or 
curtailment of its habitat or range. Herpetologists have noted the 
decline or extirpation of California red-legged frogs from the San 
Francisco Bay area (Sean J. Barry, University of California, Davis, in 
litt., 1992; Robert C. Stebbins, University of California, Berkeley, in 
litt., 1993; John S. Applegarth, herpetologist, in litt., 1993; Ed Ely, 
herpetologist, in litt., 1993), the Salinas River drainage (Lawrence E. 
Hunt, University of California, Santa Barbara, in litt., 1993), the San 
Luis Obispo, Santa Barbara, and Ventura County area (Aryan I. Roest, 
California Polytechnic State University, San Luis Obispo, in litt., 
1993; Samuel S. Sweet, University of California, Santa Barbara, in 
litt., 1993), southern California (Patrick McMonagle, herpetologist, in 
litt., 1993; John D. Goodman, zoologist, in litt., 1992; Robert B. 
Sanders, San Bernardino County Museum, in litt., 1992; John Stephenson, 
U.S. Forest Service, in litt., 1993; Michael C. Long, Eaton Canyon Park 
Nature Center, in litt., 1992; Joseph F. Copp, herpetologist, in litt., 
1993; Glenn R. Stewart, California Polytechnic University, Pomona, in 
litt., 1993; Robert Fisher, University of California, Davis, in litt., 
1993), central California (Martin R. Brittan, California State 
University, Sacramento, in litt., 1993), and the northern and southern 
Sierra Nevada foothills (Jay Wright, Feather River College, Quincy, in 
litt., 1993; Alan M. McCready, California State University, Sacramento, 
in litt., 1992).
    These observations from herpetologists and data provided by the 
researchers who petitioned the Service to list the species indicate 
that the California red-legged frog has sustained a reduction of over 
70 percent in its historic geographic range in California. Large 
aggregations of greater than 350 adults have been documented from only 
four areas. These areas included Pescadero Marsh Natural Preserve in 
coastal San Mateo County, Point Reyes National Seashore in Marin 
County, canals west of San Francisco International Airport in the San 
Francisco Bay area (Jennings et al. 1992), and Rancho San Carlos in 
Monterey County (Jeff Froke, Rancho San Carlos, in litt., 1994). The 
aggregation west of San Francisco International Airport is now thought 
to be extirpated (U.S. Fish and Wildlife Service, 1995; David Mullen, 
private consultant, pers. comm., 1994).
    Habitat loss and alteration are the primary factors that have 
negatively affected the California red-legged frog throughout its 
range. For example, in the Central Valley of California, over 90 
percent of historic wetlands have been diked, drained, or filled 
primarily for agricultural development and secondarily for urban 
development (U.S. Fish and Wildlife Service, 1978). Wetland 
alterations, clearing of vegetation, and water diversions that often 
accompany agricultural development make aquatic sites unsuitable for 
California red-legged frogs. Urbanization with its associated roadway, 
stream channelization, and large reservoir construction projects has 
significantly altered or eliminated California red-legged frog habitat, 
with the greatest impact occurring in

[[Page 25825]]

southern California. The majority of extant localities are isolated and 
fragmented remnants of larger historical populations.
    Current and future urbanization poses a significant threat to the 
California red-legged frog. Sixty-five drainages (27 percent of the 
known occurrences) are associated with urbanization threats (U.S. Fish 
and Wildlife Service, 1995). Proposed urban developments include the 
East County Area Plan in Alameda County, which involves development of 
up to 52,000 acres, and projects currently proposed in the Ruby Hills/
Arroyo Del Valle watershed and south Livermore Valley; Reservoir Canyon 
ponds in Santa Clara County; Alamo, Shadow, and Brookside Creeks in 
Contra Costa County; the Carmel River in Monterey County; and the Santa 
Ynez River in Santa Barbara County. In Santa Cruz County, a proposed 
commuter rail project linking Santa Cruz to Watsonville could increase 
urban development in southern portions of the county (Patricia O'Keefe, 
R.A.I.L.S., in litt., 1994). In San Luis Obispo County, one of three 
counties with numerous drainages supporting California red-legged 
frogs, proposed residential and/or recreational development adjacent to 
San Simeon, Santa Rosa, San Juan, and Cambria Meadows Creeks and 
Estrella and Salinas Rivers could degrade or eliminate California red-
legged frog habitat. Updates to area plans for the North Coast, San 
Luis Obispo, and Paso Robles/Atascadero areas in San Luis Obispo County 
propose rezoning of over 240,000 acres primarily for urban development. 
Between the cities of Ventura and San Luis Obispo, development already 
has eliminated California red-legged frogs from at least eight 
drainages along the coast (G. Rathbun and M. Jennings, in litt., 1993).
    Loss of habitat and decreases in habitat quality will occur as a 
result of on-site degradation of the stream environment and/or riparian 
corridor, or through modification of instream flow. Where streams or 
wetlands occur in urban areas, the quality of California red-legged 
frog habitat is degraded by a variety of factors. Among these factors 
are introduction of exotic predators, elimination of streambank 
vegetation, collecting, and loss of upland habitat.
    Water projects, which accompany urban and agricultural growth, have 
had a negative effect on California red-legged frogs and their habitat. 
The construction of large reservoirs, such as Lake Oroville, 
Whiskeytown Reservoir, Don Pedro Reservoir, Lake Berryessa, San Luis 
Reservoir, Lake Silverwood, Lake Piru, Pyramid Lake, and Lower Otay 
Lake, have eliminated California red-legged frog habitat or fragmented 
remaining aggregations (Jennings et al,. 1992).
    The timing and duration of water releases from reservoirs, 
particularly on the central California coast, can render a stream 
unsuitable for California red-legged frog reproduction (M. Jennings, in 
litt., 1993) and maintain populations of exotic predators in downstream 
areas that would normally be dry in summer (S. Sweet, in litt., 1993). 
Reservoirs are typically stocked with predatory species of fish and 
bullfrogs. These species often disperse into surrounding California 
red-legged frog habitat disrupting natural community dynamics. Hayes 
and Jennings (1988) found that California red-legged frogs generally 
were extirpated from downstream portions of a drainage 1 to 5 years 
after filling of a reservoir. In some larger drainages, however, 
isolated California red-legged frog populations have persisted 
upstream. A discussion of exotic predators appears below in Factor C: 
``Disease or predation.''
    A variety of proposed water projects threaten remaining California 
red-legged frog aggregations. Construction of major reservoirs is 
proposed on Los Banos Creek (Merced County), with Orestimba Creek 
(Stanislaus County) as an alternative reservoir site (California 
Department of Water Resources and the U.S. Bureau of Reclamation, 
1990), and on Kellogg Creek (Contra Costa County) (Contra Costa Water 
District, 1993). These drainages represent three of 14 sites remaining 
in the Central Valley hydrographic basin with known or potential 
localities of California red-legged frogs. On the Salinas River along 
the central coast, raising the height of Salinas Dam (Santa Margarita 
Lake) is proposed in San Luis Obispo County. Reservoir construction at 
this site may allow exotic predators access to formerly secure 
aggregations of California red-legged frogs isolated in upper portions 
of the watershed (L. Hunt, in litt., 1993). Other large reservoir 
projects proposed in California red-legged frog habitat include the 
Upper Nacimiento River Project and Arroyo Seco Dam Project in Monterey 
County. In Santa Barbara and Ventura counties, proposed dams on the 
Santa Ynez River, Sisquoc River, and Sespe Creek also would eliminate 
or degrade California red-legged frog habitat (Sam Sweet, pers. comm., 
1993).
    Water diversions, groundwater well development, and stock pond or 
small reservoir construction projects degrade or eliminate habitat. 
Diverting water from natural habitats to these projects disrupts the 
natural hydrologic regime. During periods of drought, reduced 
availability of water within natural drainages combined with drawdown 
from the impoundments, disrupts reproduction, foraging, estivation and 
dispersal (U.S. Fish and Wildlife Service, 1995) (see Factor E, ``Other 
natural or man-made factors affecting its continued existence'' below 
for additional discussion of the effects of drought). Proposed or 
existing water diversions on the central coast potentially affect the 
following drainages: San Simeon, Santa Rosa, Van Gordon, Villa, San 
Luis Obispo, Pico, and Little Pico Creeks, Arroyo del Puerta, and 
Arroyo Laguna in San Luis Obispo County; the Carmel and Salinas Rivers 
in Monterey County; and Canada del Refugio in Santa Barbara County. 
Most waterways on the south coast of Santa Barbara County are diverted 
to agriculture and other uses, leaving some completely desiccated 
(Brian Trautwein, Santa Barbara Urban Creeks Council, in litt., 1994). 
Stock ponds and small reservoirs also support populations of exotic 
fishes and bullfrogs (G. Rathbun and M. Jennings, in litt., 1993). The 
proposed coastal branch of the State Water Project is likely to result 
in a number of adverse effects to California red-legged frogs in many 
of the 24 areas receiving State water. These effects include, (1) 
altered water regimes in existing and any proposed delivery facilities 
of individual water districts, (2) spills, leaks, malfunctions, and 
operational errors that lead to introduction of exotic predators into 
isolated stream segments currently occupied by California red-legged 
frogs, and (3) indirect effects associated with expanded urbanization.
    Storm damage repair and flood control maintenance on streams are 
current threats to California red-legged frogs. Routine flood control 
maintenance includes vegetation removal, herbicide spraying, shaping of 
banks to control erosion, and desilting of the creek, all of which 
degrade California red-legged frog habitat. In San Luis Obispo and 
Santa Barbara counties, maintenance work is planned for 14 and 11 
drainages, respectively. All 25 drainages are known to be inhabited by 
California red-legged frogs and represent 35 percent of the occupied 
drainages in these two counties (U.S. Fish and Wildlife Service 1995). 
In Santa Barbara County, a larger channel maintenance project is 
proposed for a 4.5-mile stretch of the Santa Ynez River near Lompoc and 
a 10-mile segment of San Antonio Creek, both of which support 
California red-legged frog habitat.
    Management of water bodies for flood control also has the potential 
to adversely impact California red-legged

[[Page 25826]]

frog localities. In San Mateo County, poorly timed releases of storm 
water from Horse Stable Pond at Sharp Park in February 1992, resulted 
in exposure and desiccation of 62 California red-legged frog egg masses 
(Todd Steiner, Earth Island Institute, in litt., 1994). Channel 
maintenance at San Francisco International Airport may have contributed 
to extirpation of one of the four largest remaining aggregations of the 
California red-legged frog.
    Routine road maintenance, trail development, and facilities 
construction activities associated with parks in or adjacent to 
California red-legged frog habitat can result in increased siltation in 
the stream. If this siltation occurs during the breeding season, 
asphyxiation of eggs and small California red-legged frog larvae can 
result. On the upper Santa Ynez River and Sespe Creek in Los Padres 
National Forest, Sweet (pers. comm., 1993) observed California red-
legged frog egg masses smothered with silt. Construction activities in 
or adjacent to streams at Butano and Portola State Parks in San Mateo 
County; Big Basin, Wilder Ranch, and Henry Cowell State Parks in Santa 
Cruz County; and Mt. Diablo State Park in Contra Costa County have the 
potential to adversely affect California red-legged frogs inhabiting 
downstream reaches (Coyote Creek Riparian Station, in litt., 1993).
    Placer mining may threaten California red-legged frog habitat. 
Jennings (pers. comm., 1994) observed heavy siltation in late spring 
and summer in portions of Piru Creek known to support California red-
legged frogs. The siltation resulted from upstream gold mining. Deep 
holes in streams created by instream placer mining also may provide 
habitat for exotic predatory fish (Jennings, pers. comm., 1994). 
Creeks, streams and rivers are open to suction dredging throughout the 
year in 13 of 22 counties within the current range of the California 
red-legged frog (State of California 1994).
    Road-killed California red-legged frogs have been documented at 
several locations in San Mateo and Santa Cruz Counties (Coyote Creek 
Riparian Station, in litt., 1993; Mike Westphal, Coyote Creek Riparian 
Station, in litt., 1995). Road kills may deplete frog aggregations in 
borderline habitat and otherwise protected areas. Where roads cross or 
lie adjacent to California red-legged frog habitat, they may act as 
barriers to seasonal movement and dispersal.
    Livestock grazing is another form of habitat alteration that is 
contributing to declines in the California red-legged frog. Numerous 
studies, summarized in Behnke and Raleigh (1978) and Kauffman and 
Krueger (1984), have shown that livestock grazing negatively affects 
riparian habitat. Cattle have an adverse affect on riparian and other 
wetland habitats because they tend to concentrate in these areas, 
particularly during the dry season (Marlow and Pogacnik 1985). Cattle 
trample and eat emergent and riparian vegetation, often eliminating or 
severely reducing plant cover (Gunderson 1968, Duff 1979). Loss of 
riparian vegetation results in increased water temperatures (Van Velson 
1979), which encourage bullfrog reproduction. Riparian vegetation loss 
due to cattle grazing includes the loss of willows (Duff 1979), which 
are associated with the highest densities of California red-legged 
frogs (Hayes and Jennings 1988, Jennings 1988b). Cattle grazing also 
results in increased erosion in the watershed (Lusby 1970, Winegar 
1977), which accelerates the sedimentation of deep pools (Gunderson 
1968) used by California red-legged frogs and adversely affects aquatic 
invertebrates (Cordone and Kelley 1961). Aquatic invertebrates are 
common prey items of California red-legged frogs.
    Behnke and Zarn (1976) identified livestock grazing as the greatest 
threat to the integrity of stream habitat in the western United States. 
Numerous symposia and publications have documented the detrimental 
effects of livestock grazing on streams and riparian habitats (Johnson 
and Jones 1977; Meehan and Platts 1978; Behnke and Raleigh 1979; Bowers 
et al. 1979; Cope 1979; Platts 1981; Ohmart and Anderson 1982 and 1986; 
Peek and Dalke 1982; Kauffman et al. 1983; Menke 1983; Kauffman and 
Krueger 1984; Johnson et al. 1985; GAO 1988; Clary and Webster 1989; 
Gresswell et al. 1989; Kinch 1989; Minshall et al. 1989; Chaney et al. 
1990 and 1993). These effects include nutrient loading, reduction of 
shade and cover with resultant increases in water temperature, 
increased intermittent flows, changes in stream channel morphology, and 
the addition of sediment due to bank degradation and off-site soil 
erosion. Indirect effects of increased water temperatures can be lethal 
to aquatic species and include: creating a more favorable environment 
for introduced species, changing the food chain, degrading water 
quality through decreased dissolved oxygen, increased production of 
algae, and increased pH and ammonia.
    Various studies have shown that water temperatures have been 
reduced when streambank vegetative cover is protected from grazing. 
Storch (1979) found that daily fluctuations of water temperatures in 
late August and early September averaged 27 deg. F outside an exclosure 
on Camp Creek, Oregon that was ungrazed for 10 years, compared to 
13 deg. F inside the exclosure. Also, maximum water temperatures 
outside the exclosure averaged 11 deg. F higher than inside the 
exclosure. Van Velson (1979) reported that average water temperatures 
in Otter Creek, Nebraska, decreased 3 deg. F after livestock were 
excluded for 1 year.
    Grazing effects are not limited to riparian areas. Improper grazing 
of upland vegetation can expose soils to erosive impacts of rain drops, 
reduce water infiltration, and accelerate runoff. This can erode 
topsoil and cut rills and gullies, concentrating runoff, deepening 
gullies, lowering water tables, and increasing sediment production 
(Chaney et al. 1993). Sediment introduced into streams can alter 
primary productivity and food supply, fill interstitial spaces in 
stream bed material, impeding water flow, reducing dissolved oxygen 
levels, and restricting waste removal (Chapman 1988). Suspended 
sediments reduce light penetration to plants and reduce oxygen carrying 
capacity of the water (Ohmart and Anderson 1982). Reduction in 
photosynthesis and primary production decreases productivity of the 
entire ecosystem (Minshall et al. 1989).
    Livestock grazing can cause a nutrient loading problem (due to 
urination and defecation) in areas where cattle are concentrated near 
the water (Doran et al. 1981), but in other areas it can reduce 
nutrients through removal of riparian vegetation (Fisher 1972). 
Riparian vegetation provides organic material for approximately 50 
percent of a stream's nutrient energy (Cummins 1974). Detritus from 
such plants is a principal source of food for aquatic invertebrates 
(Minshall 1967; Meehan et al. 1977). Streamside vegetation also 
provides habitat for terrestrial insects, another important dietary 
component for other aquatic or riparian associated species.
    Jennings et al. (1992) found livestock grazing to occur at all 
known historic locations of the California red-legged frog in the 
Central Valley hydrographic basin. Livestock grazing also has been 
implicated as a contributing factor in the decline and disappearance of 
California red-legged frogs from the lower Salinas River (L. Hunt, in 
litt., 1993) and the San Francisco peninsula (S. Barry, in litt., 
1992). Two of the 14 remaining aggregations of California red-legged 
frogs in the Central Valley hydrographic basin (Corral Hollow 
Ecological Reserve and Frank Raines Regional Park) are threatened by

[[Page 25827]]

sedimentation of aquatic habitats either directly or indirectly caused 
by livestock grazing and off-road vehicle use (Jennings et al. 1992). 
Galen Rathbun (National Biological Service, pers. comm., 1993) reports 
that grazing is adversely altering California red-legged frog habitat 
on Pico, Van Gordon, San Simeon, Santa Rosa, Cambria Meadows, and 
Cayucos Creeks in San Luis Obispo County. Grazing practices can, 
however, be modified to minimize impacts to California red-legged 
frogs. Five-fold increases in California red-legged frog populations on 
Rancho San Carlos in Monterey County may be attributable in part to 
modifications of grazing programs (J. Froke, in litt., 1994).
    In addition to cattle, feral pigs (Sus scrofa) also disturb the 
riparian zone through their rooting, wallowing and foraging behavior in 
the shallow margins of water bodies. Feral pigs disturb and destroy 
vegetative cover, trample plants and seedlings, and cause erosion. At 
Pinnacles National Monument, soil compaction and possible disturbance 
of frog eggs caused by feral pigs have been noted in California red-
legged frog habitat (Stanley Albright, National Park Service, in litt., 
1994).
    Off-road vehicle use adversely affects California red-legged frogs 
in ways similar to livestock grazing and feral pig disturbance. Off-
road vehicles damage riparian vegetation, increase siltation in pools, 
disturb the water in stream channels and crush eggs, larvae, juveniles, 
and adults. California red-legged frogs were eliminated in part by off-
road vehicle activities at the Mojave River above Hesperia, at Rincon 
Station on the west fork of the San Gabriel River, and in Piru Creek 
above Pyramid Lake (M. Jennings, pers. comm., 1993).
    Heavy recreational use of parks (e.g., fishing, hiking, exploring) 
also can degrade habitat for the California red-legged frog. At Big 
Basin Redwood Park in Santa Cruz County, heavy recreational use may 
have contributed to the disappearance of California red-legged frogs 
from Opal Creek (Coyote Creek Riparian Station, in litt., 1993).
    Timber harvest threatens California red-legged frogs through loss 
of riparian vegetation and increased erosion in the watershed, which 
fills pools with sediment and smothers egg masses. In Santa Cruz 
County, timber harvest is proposed adjacent to Adams Creek (Celia 
Scott, private citizen, pers. comm., 1993), Whitehouse Creek (U.S. Fish 
and Wildlife Service 1995) and occurs periodically on a tributary of 
Blooms Creek (Coyote Creek Riparian Station, in litt., 1993). The 
proposed timber harvests would occur in three of 18 streams in the 
County that support California red-legged frogs. In Pescadero Creek at 
Portola State Park (San Mateo County), erosion and siltation caused by 
severe winter storms and upstream logging operations may have been the 
cause of the disappearance of California red-legged frogs from this 
portion of the stream (Coyote Creek Riparian Station, in litt., 1993).
    B. Overutilization for commercial, recreational, scientific, or 
educational purposes. Records of harvesting California red-legged frogs 
for human consumption date back to an account by Lockington (1879) of 
the commercial harvest of this species for San Francisco fish markets. 
From 1890 to 1900, the California red-legged frog supported a 
significant commercial harvest (Smith 1895) of about 80,000 frogs 
annually (Jennings and Hayes 1984). Counties surrounding San Francisco 
Bay provided the bulk of the frog harvest in the early to mid 1890s, 
with the Sacramento and San Joaquin Valleys increasing in importance by 
the end of the decade (Chamberlain 1898, Jennings and Hayes 1985). By 
1900, harvest figures for California red-legged frogs fell 
dramatically, indicating that overharvesting may have occurred. 
Jennings and Hayes (1985) hypothesized that this rapid decline in the 
California red-legged frog population was the result of selective 
harvesting of the larger females. Introduction of the bullfrog in 
California in 1896 was probably in response to the dwindling California 
red-legged frog population (Jennings and Hayes 1985). Continued 
harvesting of California red-legged frogs for food by local individuals 
has been reported for the Central Coast region (Coyote Creek Riparian 
Station, in litt., 1993). California red-legged frogs reportedly taste 
better than bullfrogs, a statement first made by Dickerson (1906).
    Prior to 1950, California red-legged frogs were used sporadically 
for research in high schools and universities. At present, the 
California red-legged frog is available commercially from suppliers 
located outside California in the pet trade. Because the State of 
California prohibits possession of wild California red-legged frogs 
without a permit, frogs sold in the pet trade presumably are reared in 
captivity (M. Jennings, pers. comm., 1993).
    C. Disease or predation. There have been no documented instances of 
disease adversely affecting the California red-legged frog.
    Few data are available on the effect of native predators on the 
California red-legged frog. Bitterns (Botaurus lentiginosus) and black-
crowned night herons (Nycticorax nycticorax) are likely predators of 
adult frogs (Jennings and Hayes 1990). Juvenile California red-legged 
frogs, which are more active diurnally and less wary than adults, may 
be more susceptible to predation by diurnal predators, such as the 
great blue heron (Ardea herodias) and several species of garter snakes 
(Thamnophis spp.) (Fitch 1940, Fox 1952), including the endangered San 
Francisco garter snake (Thamnophis sirtalis tetrataenia) (Barry 1978, 
Wharton et al. 1986). Recent postmetamorphs also may be particularly 
vulnerable to predation by garter snakes, as was found in other species 
of ranid frogs by Arnold and Wassersug (1978). Raccoons (Procyon 
lotor), which are abundant in urban settings, were the likely predator 
of eight radio-tagged California red-legged frogs in the riparian 
corridor of Pico and San Simeon Creeks in San Luis Obispo County 
(Rathbun, in litt., 1994). Other possible, but undocumented mammalian 
predators include striped skunks (Mephitis mephitis), spotted skunks 
(Spilogale putorius), and red fox (Vulpes fulva). Larvae may be preyed 
upon by aquatic beetles and damsel fly naiads (Karl Malamud-Roam, 
Contra Costa County Mosquito and Vector Control District, in litt., 
1994).
    Introduced predators of particular concern are the bullfrog, red 
swamp crayfish (Procambarus clarkii), signal crayfish (Pacifastacus 
leniusculus), and several species of fish, including bass, catfish 
(Ictalurus spp.), sunfish, and mosquitofish (Moyle 1973; Hayes and 
Jennings 1986, 1988). All species were introduced into California in 
the late 1800s and early 1900s, and through range expansions, 
reintroductions, and transplants have become established throughout 
most of the State (Riegel 1959, Bury and Luckenbach 1976, Moyle 1976).
    Several researchers in central California have noted the decline 
and eventual disappearance of California red-legged frogs once 
bullfrogs become established at the same site (L. Hunt, in litt, 1993; 
S. Barry, in litt., 1992; S. Sweet, in litt., 1993). Joseph DiDonato 
(East Bay Regional Park District, pers. comm., 1994) has observed the 
disappearance of California red-legged frogs from Pleasanton Ridge in 
Alameda County within the last ten years. Today, all former California 
red-legged frog habitat on Pleasanton Ridge is occupied by bullfrogs. 
Moyle (1973) attributed the disappearance of California red-legged 
frogs from the San Joaquin Valley and Sierran foothill region primarily 
to a combination of bullfrog predation and

[[Page 25828]]

competition. All sites in the Sierra Nevada foothills that supported 
California red-legged frogs in the 1970s now are inhabited by bullfrogs 
(M. Jennings, in litt., 1993). Over the last decade, Jennings (in 
litt., 1993) has observed bullfrogs moving upstream and/or downstream 
into formerly pristine California red-legged frog habitat in a number 
of drainages, including streams in Ventura, Santa Barbara, San Luis 
Obispo, Merced, Stanislaus, and San Mateo counties. Bullfrogs are 
introduced into drainages by stocking of reservoirs and stock ponds, 
dispersal and colonization, conveyance of project water from other 
streams inhabited by these exotics, and releases by individuals. At The 
Nature Conservancy's Santa Rosa Plateau Reserve in Riverside County 
(the only site south of the Santa Clara River drainage supporting 
California red-legged frogs), a docent found a school teacher 
attempting to introduce bullfrog tadpoles into the preserve in the 
1980s (M. Jennings, in litt., 1993). Additional bullfrogs were removed 
from the preserve in 1989 after apparent introductions from a nearby 
frog jumping contest (M. Jennings, in litt., 1994). Once established, 
it is extremely difficult to eliminate bullfrogs (M. Jennings, in 
litt., 1993; Cecil Schwalbe, National Park Service, Tuscon, Arizona, 
pers. comm., 1993; Frank Slavens, Woodland Park Zoological Gardens, 
Seattle, Washington, pers. comm., 1993). Over 60 percent of the streams 
or drainages currently known to support California red-legged frogs 
also are inhabited by bullfrogs, either in association with California 
red-legged frogs or in other portions of the drainage (U.S. Fish and 
Wildlife Service 1995). Based on documented rates of local extinction, 
the Service concludes that eventually California red-legged frogs will 
be locally extirpated from these 149 streams.
    Bullfrogs prey on California red-legged frogs (S. Sweet, in litt., 
1993), other ranid frogs (Twedt 1993) and other amphibians and aquatic 
reptiles (Schwalbe and Rosen 1988). Twedt (1993) documented four 
juvenile northern red-legged frogs among the contents of 22 adult 
bullfrog stomachs. He also found a subadult bullfrog in one of the 
adult bullfrog stomachs. This prey item was between the size of an 
adult male (approximately 80 mm (3.1 in.)) and adult female 
(approximately 85 mm (3.3 in.)) red-legged frog, indicating that 
bullfrogs could prey on subadult red-legged frogs. Stuart and Painter 
(1993) found evidence of cannibalistic behavior in bullfrogs. A stomach 
content analysis revealed 87 percent of total volume by weight was 
composed of newly-metamorphosed and larval Rana. Bullfrogs may have a 
competitive advantage over California red-legged frogs because of their 
(1) larger size, (2) generalized food habits (Bury and Whelan 1984), 
(3) extended breeding season (Storer 1933), which allows for production 
of two clutches of up to 20,000 eggs during a breeding season (Emlen 
1977), and (4) larvae being unpalatable to predatory fish (Kruse and 
Francis 1977). Bullfrogs also interfere with red-legged frog 
reproduction. Several researchers have noted male red-legged frogs in 
amplexus with (mounted on) both male and female bullfrogs (Jennings and 
Hayes 1990; Twedt 1993; M. Jennings, in litt., 1993; Stebbins in litt., 
1993). However, the extent to which bullfrog predation, competition, 
and reproductive interference adversely affects red-legged frogs has 
not been studied in the field (Hayes and Jennings 1986). Habitat 
alterations, including removal of riparian or aquatic vegetation, 
reduced stream flows, and sedimentation of pools, often provide 
conditions detrimental to red-legged frogs but favorable to bullfrogs 
(Hayes and Jennings 1986; Jennings 1988b; Jennings, pers. comm., 1993).
    Hayes and Jennings (1986, 1988) found a negative correlation 
between the abundance of introduced fish species and California red-
legged frogs. These authors noted that aquatic sites where introduced 
fishes were abundant rarely had native ranids, and when present, ranid 
populations were small. A similar negative correlation was reported by 
Hunt (in litt., 1993) for California red-legged frogs in the Salinas 
River drainage, by DiDonato (in litt., 1994) on East Bay Regional Park 
District properties in the San Francisco Bay area, by Shaffer (in 
litt., 1994) for the inner coast range, and by Moyle (1973) for the 
foothill yellow-legged frog. These references suggest that the observed 
negative correlation between California red-legged frogs and non-native 
fish is a general principal. Of 32 streams examined by Hayes and 
Jennings (1988), introduced fishes were found in 44 percent.
    Results of a recent study in artificial ponds showed that 
mosquitofish and bluegill (Lepomis macrochirus) were significant 
predators of California red-legged frog larvae (Schmieder and Nauman 
1994). However, California red-legged frogs have been found in 
association with mosquitofish in Corral Hollow Creek (Alameda and San 
Joaquin counties) (T. Strange, pers. comm., 1994) and in three 
waterbodies on East Bay Regional Park properties in Contra Costa County 
(K. Swaim, in litt., 1994). Malamud-Roam (in litt, 1994) reported that 
mosquitofish occur in at least four streams in Contra Costa County 
known to support California red-legged frogs. Mosquitofish also may 
compete with California red-legged frogs by consuming aquatic insects 
that are potential food sources for postmetamorphic frogs. Mosquitofish 
have become established statewide and are stocked routinely by mosquito 
abatement districts as a mosquito control measure (Moyle 1976).
    D. The inadequacy of existing regulatory mechanisms. Although the 
California red-legged frog is classified as a ``Species of Special 
Concern'' by the State of California (Steinhart 1990) and may not be 
taken without an approved scientific collecting permit, this 
designation provides no special, legally mandated protection of the 
species and its habitat. In 1972, the California Fish and Game 
Commission amended its sport fishing regulations to prohibit take or 
possession of California red-legged frogs (Bury and Stewart 1973). 
However, because of the rarity of the California red-legged frog and 
similarity to the more common bullfrog, protection of this taxon by 
State wardens and rangers may be compromised (Coyote Creek Riparian 
Station, in litt., 1993).
    Section 1603 of the California Fish and Game Code authorizes the 
Department of Fish and Game (CDFG) to regulate streambed alteration. 
The Department must be notified and approve any work that substantially 
diverts, alters, or obstructs the natural flow or substantially changes 
the bed, channel or banks of any river, stream, or lake. If an existing 
fish or wildlife resource may be substantially adversely affected by a 
project, CDFG must submit proposals to protect the species within 30 
days. However, if the Department does not respond within 30 days of 
notification, the applicant may proceed with the work.
    Section 404 of the Clean Water Act is the primary Federal law that 
potentially provides some protection for aquatic habitats of the 
California red-legged frog, if the habitats are determined by the U.S. 
Army Corps of Engineers (Corps) to be jurisdictional areas (i.e., 
waters of the United States). Under section 404, nationwide permits, 
which undergo minimal public and agency review, can be issued for 
projects involving less than 10 acres of wetlands above the headwaters 
(i.e., streams with less than five cubic feet per second (cfs) mean 
annual flow) or for isolated waters, unless a listed species may be 
adversely affected. Many aggregations of

[[Page 25829]]

California red-legged frogs occur in isolated wetlands and coastal 
streams that may have mean annual flows less than five cfs. Individual 
permits, which are subject to more extensive review, could be required 
for projects that have more than minimal impacts to waters of the 
United States. The Clean Water Act does not afford any special 
protection for candidate species. However, when the California red-
legged frog is listed, the Corps will be required by section 7 of the 
Act to consult and obtain the concurrence of the Service prior to the 
authorization of any section 404 permit affecting California red-legged 
frog habitat.
    Additionally and equally important, the upland habitats adjacent to 
riparian zones are not provided any protection by Section 404 of the 
Clean Water Act. Upland areas provide estivation and dispersal habitats 
for this species.
    Federal lands, including those of the Forest Service, National Park 
Service, Bureau of Land Management, Bureau of Reclamation, and 
Department of Defense, encompass approximately 10 percent of the 
current known range of the California red-legged frog. Multiple land 
use management, as currently practiced by the Forest Service, Bureau of 
Land Management, and National Park Service, does not provide long-term 
protection for the California red-legged frog. State, County, and 
Regional Park lands provide some protection from some threats, however, 
these parks are managed for multiple uses.
    The National Environmental Policy Act (NEPA) and California 
Environmental Quality Act (CEQA) require an intensive environmental 
review of projects that may adversely affect a Federally listed 
species. However, project proponents are not required to avoid impacts 
to non-listed species, and proposed mitigation measures are frequently 
not adequately implemented. As with section 404 permits, the Service's 
comments through these environmental review processes are only 
advisory. The Service is aware of a proposed recreational development 
in Santa Cruz County undergoing environmental review that is expected 
to extirpate an estimated 10 percent of the total remaining numbers of 
the California red-legged frog (Westphal in litt. 1995).
    The California Coastal Act regulates the approval of developments 
within the costal zone. Although a significant slowing in wetland 
losses has occurred, the continued loss and degradation of coastal 
wetlands since the California Coastal Act was enacted in 1974 attests 
to the limitations of this legislation.
    E. Other natural or man-made factors affecting its continued 
existence. Six consecutive years of drought (1986-1992) in California 
severely affected remaining California red-legged frogs in the Sierran 
foothills. Many sites in intermittent streams that held California red-
legged frogs before the drought were completely dry during field 
surveys conducted between 1985 to 1992 (Jennings et al. 1992). Sites 
still holding pools of water had water levels so low that access by 
predators was enhanced. Livestock grazing at many sites exacerbated 
effects of the drought by limiting or preventing riparian habitat 
regeneration (Jennings et al. 1992). Long-term survival of California 
red-legged frogs may be compromised by the elimination of refuge areas 
during times of the year when the stream is dry (Rathbun, in litt., 
1994). However, California red-legged frog populations are undoubtedly 
capable of recovering from drought, provided other factors have not 
irreparably degraded their habitat, or California red-legged frogs have 
not been completely extirpated from the drainage.
    Drought also may play a role in decreased California red-legged 
frog reproduction where frogs occur in coastal lagoons. High salinities 
in the Pescadero Marsh (San Mateo County) have been attributed to 
drought conditions in the watershed. At the Pescadero Marsh Natural 
Preserve, Jennings and Hayes (1990) found many dead egg masses in a 
portion of the marsh that were killed by excessive (>4.5 parts per 
thousand) salinity levels. Rathbun et al. (1991) speculated that the 
absence of California red-legged frogs in lower Santa Rosa Creek and 
lagoon in San Luis Obispo County was due to long-term drought 
exacerbated by instream flow withdrawals. Since the end of the drought 
California red-legged frog numbers reportedly have increased in lower 
Santa Rosa Creek (Rathbun in litt. 1994; G. Schmitt, United Residential 
Lot Owners of Cambria, Inc. in litt. 1994) probably as a result of 
increased rainfall in the winter of 1992-1993. Increased salinities 
were recorded in several other coastal lagoons during the drought years 
(C. Swift and K. Worcester, pers. comm. in Jennings et al. 1992). 
Increased salinity could also result from periodic overtopping of the 
beach bar during high tides or by storm waves (D. Asquith, private 
consultant, in litt. 1994). In 1993, Jennings (pers. comm., 1993) 
reported the loss of California red-legged frog egg masses from 
increased salinity and unusual flooding in Arroyo Laguna in San Luis 
Obispo County. Because significant numbers of California red-legged 
frogs occur in coastal lagoons on the central California coast, drought 
has the potential to severely reduce production of California red-
legged frogs over a significant portion of their remaining range.
    The overall effect of contaminants on California red-legged frogs 
has not been studied. Only one incident of California red-legged frog 
mortality is known from a diesel and gasoline spill in a tributary of 
Blooms Creek (Santa Cruz County) (Coyote Creek Riparian Station, in 
litt., 1993).
    Periodic wildfires may adversely affect California red-legged frogs 
by causing direct mortality, destroying streamside vegetation, or 
eliminating vegetation that protects the watershed. The 1991 Lions Fire 
on upper Sespe Creek in the Los Padres National Forest destroyed known 
California red-legged frog habitat (S. Sweet, pers. comm., 1993). 
Following the fire, extensive erosion in the watershed also negatively 
affected California red-legged frogs and their habitat (S. Sweet, pers. 
comm., 1993).
    Extensive flooding has been cited by Jennings and Hayes (1994a) as 
a significant contributing factor in the extirpation of the California 
red-legged frog from desert drainages of southern California. For 
example, in the Mojave River drainage, no verifiable records or 
sightings exist of California red-legged frogs after 1968 (Jennings and 
Hayes 1994a). The disappearance of this species from the drainage 
coincided with a catastrophic flood event in the Mojave River in the 
winters of 1968 and 1969. Extensive flooding in other portions of the 
California red-legged frog range may have combined with other factors 
to eliminate California red-legged frog aggregations (Richard Seymour, 
Coyote Creek Riparian Station, in litt., 1993; D. Martin, pers. comm., 
1994).
    A considerable amount of occupied California red-legged habitat 
exists in the form of isolated patches along stream courses. These 
patches of suitable habitat represent mere remnants of a much larger 
historical habitat that once covered whole drainages. Fragments of 
formerly extensive populations of California red-legged frogs are now 
isolated from other populations. Populations isolated in habitat 
fragments are vulnerable to extinction through random environmental 
events or anthropogenic catastrophes. With only three of 243 known 
creeks or drainages supporting populations of over 350 adults, all 
remaining occurrences are considered vulnerable to these threats. Once 
a local

[[Page 25830]]

extinction event occurs in an isolated habitat fragment, the 
opportunity for recolonization from a source population is reduced. 
Thus, local extinctions via stochastic processes, coupled with habitat 
fragmentation may represent a substantial threat to the continued 
existence of the California red-legged frog over much of its range.
    The Service has carefully assessed the best scientific and 
commercial data available regarding the past, present, and future 
threats faced by the California red-legged frog in determining to make 
this final decision. Based on this evaluation, the preferred action is 
to list the California red-legged frog (Rana aurora draytonii) as 
threatened. This taxon has been extirpated from 70 percent of its 
former range. Although California red-legged frogs are now known to be 
found in more locations within their present range than previously 
thought, factors adversely affecting the California red-legged frog are 
known to exist in 83 percent of the drainages supporting the taxon 
(U.S. Fish and Wildlife Service 1995). These factors include but are 
not limited to (1) urban encroachment, (2) construction of large and 
small reservoirs, water diversions and well development, (3) flood 
control maintenance, (4) road maintenance, (5) placer mining, (6) 
livestock grazing and feral pigs, (7) off-road vehicle use, and (8) 
introduction or presence of exotic predators and competitors. The 
remaining 17 percent of occupied drainages, the majority located in 
Monterey, Santa Barbara, and San Luis Obispo counties, currently are 
not known to be subject to the above threats. The California red-legged 
frog, therefore, more appropriately fits the definition of a threatened 
species. For the reasons discussed below, critical habitat has not been 
proposed.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as: (I) the 
specific areas within the geographical area occupied by a species, at 
the time it is listed in accordance with the Act, on which are found 
those physical or biological features (I) essential to the conservation 
of the species and (II) that may require special management 
considerations or protection; and (ii) specific areas outside the 
geographical area occupied by a species at the time it is listed, upon 
a determination that such areas are essential for the conservation of 
the species. ``Conservation'' means the use of all methods and 
procedures needed to bring the species to the point at which listing 
under the Act is no longer necessary.
    Section 4(a)(3) of the Act, as amended, and implementing 
regulations (50 CFR 424.12) require that, to the maximum extent prudent 
and determinable, the Secretary designate critical habitat at the time 
a species is determined to be endangered or threatened. The Service 
finds that designation of critical habitat is not prudent for the 
California red-legged frog at this time. Service regulations (50 CFR 
424.12(a)(1)) state that designation of critical habitat is not prudent 
when one or both of the following situations exist--(1) The species is 
threatened by taking or other human activity, and identification of 
critical habitat can be expected to increase the degree of threat to 
the species, or (2) such designation of critical habitat would not be 
beneficial to the species.
    As discussed under Factor B in the ``Summary of Factors Affecting 
the Species'' section, the California red-legged frog has been and 
continues to be threatened by taking, an activity difficult to control. 
Listing of the frog may result in an increase in the threat of 
vandalism, a concern expressed by the petitioners and other experts (M. 
Jennings, S. Sweet, pers. comm., 1993; D. Martin, pers. comm., 1994). 
California red-legged frogs occur in isolated and fragmented wetland 
habitat on private property and are at risk from vandalism. Publication 
of specific localities, which would be required in proposing critical 
habitat, would reveal precise locality data and thereby make the 
species more vulnerable to acts of vandalism, and increase the 
difficulties of enforcement. Martin (pers. comm., 1994) has observed 
acts of vandalism by private landowners once they learned of the 
presence of Yosemite toads (Bufo canorus), on their property. The 
Yosemite toad is a species of concern to the Service (former category 2 
species, 59 FR 58995).
    In addition, a significant market exists in California for frog 
meat, with bullfrogs as the primary species sold. In 1993, the 
California Department of Fish and Game arrested a number of individuals 
involved in illegal collection and sale of large numbers of bullfrogs 
to San Francisco fish markets (California Department of Fish and Game 
1993). To the untrained eye, the California red-legged frog looks very 
similar to a bullfrog and could be accidentally taken for the market. 
California red-legged frogs also could be taken intentionally as they 
are reported to be more palatable (Coyote Creek Riparian Station, in 
litt., 1993; Jennings, pers. comm., 1994). The California red-legged 
frog would be more vulnerable to collection for market consumption if 
precise locality data were published for this species. Protection of 
California red-legged frog habitat will be addressed in the recovery 
process and through the section 7 consultation process. Therefore, due 
to the serious potential for increased, unauthorized take, the Service 
has determined that designation of critical habitat for the California 
red-legged frog is not prudent.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened under the Endangered Species Act include recognition, 
recovery actions, requirements for Federal protection, and prohibitions 
against certain practices. Recognition through listing results in 
public awareness and conservation actions by Federal, State, and local 
agencies, private organizations, and individuals. The Act provides for 
possible land acquisition and cooperation with the States and requires 
that recovery actions be carried out for all listed species. The 
protection required of Federal agencies and the prohibitions against 
taking and harm are discussed, in part, below.
    Section 7(a) of the Act, as amended, requires Federal agencies to 
evaluate their actions with respect to any species that is proposed or 
listed as endangered or threatened and with respect to its critical 
habitat, if any is being designated. Regulations implementing this 
interagency cooperation provision of the Act are codified at 50 CFR 
part 402. Section 7(a)(4) of the Act requires Federal agencies to 
confer with the Service on any action that is likely to jeopardize the 
continued existence of a species proposed for listing or result in 
destruction or adverse modification of proposed critical habitat. If a 
species is listed subsequently, section 7(a)(2) requires Federal 
agencies to ensure that activities they authorize, fund, or carry out 
are not likely to jeopardize the continued existence of the species or 
destroy or adversely modify its critical habitat. If a Federal action 
may affect a listed species or its critical habitat, the responsible 
Federal agency must enter into formal consultation with the Service.
    Federal agencies that may be involved as a result of this final 
rule are the Bureau of Reclamation, Bureau of Land Management, National 
Park Service, Forest Service, and the Departments of the Army, Navy and 
Air Force. At several parks, the National Park Service has conducted or 
is planning to conduct status surveys for California red-legged frogs 
(Daphne A. Hatch, National Park Service, in litt., 1993; James 
Sleznick, National Park Service, in litt., 1992;

[[Page 25831]]

Gary Fellers, National Park Service, pers. comm., 1993). The Forest 
Service has conducted and has ongoing amphibian surveys in many 
National Forests within the historic range of the California red-legged 
frog (J. Stephenson, pers. comm., 1993; D. Martin, pers. comm., 1993; 
Maeton Freel, U.S. Forest Service, pers. comm., 1994). In Los Padres 
National Forest, the Forest Service, in a cooperative effort with other 
Federal and State agencies, has altered flow regimes in Piru Creek 
between Lake Pyramid Lake and Lake Piru to benefit the endangered 
arroyo southwestern toad. Although no specific studies have been done, 
these flow regime changes also may benefit the California red-legged 
frog (Frederick Gientke, United Water Conservation District, in litt., 
1994). The Forest Service has also designated more than 31 miles of 
Sespe Creek in Los Padres National Forest as ``Wild and Scenic'' under 
the National Wild and Scenic Rivers Act of 1968.
    The Contra Costa Water District is constructing a large reservoir 
construction project (Los Vaqueros Reservoir) on Kellogg Creek, Contra 
Costa County (Contra Costa Water District 1993). The Bureau of 
Reclamation's role in this project is to amend water service contracts 
and modify water rights to facilitate project construction (Penny 
Howard, U.S. Bureau of Reclamation, in litt., 1994). A mitigation and 
monitoring program is proposed to compensate for California red-legged 
frog habitat losses at Los Vaqueros. The mitigation plan includes a 
bullfrog and exotic fish control program to be carried out for the life 
of the reservoir project (Contra Costa Water District 1993). The 
potential for success of the mitigation plan is unknown. In addition, 
Bureau of Reclamation projects, including small loan projects in 
Monterey County, the Cachuma project in Santa Barbara County, the San 
Felipe project in San Benito and Santa Clara counties, and the Solano 
project in Solano County, involve water contract renewals as well as 
road maintenance activities and grazing leases, all of which may affect 
California red-legged frogs. The U.S. Army Corps of Engineers would be 
involved in many of these projects through their permitting authority 
under section 404 of the Clean Water Act.
    Any of the above mentioned Federal agencies would be required to 
consult with the Service if any action they fund, authorize, or carry 
out may affect the California red-legged frog. To the extent that their 
habitats overlap in lagoon areas, efforts made to conserve and recover 
the tidewater goby (Eucyclogobius newberryi), a Federally listed 
endangered species, may also help to conserve and recover the 
California red-legged frog.
    The Service is currently involved in the development of two Habitat 
Conservation Plans (HCP's) that could potentially protect three 
localities of California red-legged frogs. The Kern County Valley Floor 
HCP will protect a minimum of 75 percent of the existing California 
red-legged frog habitat in the Bitterwater Creek drainage. The San 
Joaquin County multispecies HCP may also protect two localities, Corral 
Hollow Creek and Lone Tree Creek. Although the development of these 
HCP's will not preclude the need to list the California red-legged 
frog, these plans, if implemented, will protect habitat for the taxon.
    The Ventura Field Office is assisting with the Santa Clara River 
Enhancement and Management Plan, which is progressing but is not 
finalized at this time. A similar plan for Rancho San Carlos (in the 
Carmel River drainage) is also underway. Early planning efforts are 
beginning for the Ventura and Santa Ynez rivers. None of these planning 
efforts preclude the need to list the species, but will provide future 
protection of habitat for the species.
    One known California red-legged frog locality in Riverside County 
and any newly discovered localities in the historic range of the 
species could be protected by ongoing ecosystem-based planning efforts 
in southern California. In 1991, the State of California established 
the Natural Communities Conservation Planning (NCCP) Program to address 
conservation needs of natural ecosystems throughout the State. The 
initial focus of the program is the coastal sage scrub community in 
southern California, however, riparian habitats will also be addressed. 
Several regional plans, including the Multi-species Conservation Plan 
(MSCP) and the Multi-habitat Conservation Plan (MHCP) of San Diego 
County, the Southern and Central Coastal Subregional NCCP/Habitat 
Conservation Plans (Southern/Central/Coastal NCCP) of Orange County, 
and the Riverside County Stephens Kangaroo rat HCP and San Bernardino 
County MSCP are under development by a consortium of county and 
municipal governments and other parties, including the California 
Department of Fish and Game and the Service. Though no plans have been 
completed to date, protection could be provided if the California red-
legged frog occurs in any of the planning areas. The one known extant 
population occurs on the Santa Rosa Plateau Reserve managed by The 
Nature Conservancy.
    The Service establishes the following recovery units within the 
historical range of the California red-legged frog: (1) The western 
foothills and Sierran foothills to 5,000 feet in elevation in the 
Central Valley Hydrographic Basin; (2) the central coast ranges from 
San Mateo and Santa Clara counties south to Ventura and Los Angeles 
counties; (3) the San Francisco Bay/Suisun Bay hydrologic basin; (4) 
southern California, south of the Tehachapi Mountains; and (5) the 
northern coast range in Marin and Sonoma counties. These five units are 
essential to the survival and recovery of the California red-legged 
frog. Designation of recovery units assists the Service and other 
agencies in identifying priority areas for conservation planning under 
the consultation (section 7) and recovery (section 4) programs.
    The Act and implementing regulations found at 50 CFR 17.32 set 
forth a series of general prohibitions and exceptions that apply to all 
threatened wildlife not covered by a special rule. With respect to the 
California red-legged frog, these prohibitions, in part, make it 
illegal for any person subject to the jurisdiction of the United States 
to take (including harass, harm, pursue, hunt, shoot, wound, kill, 
trap, capture, collect, or attempt any such conduct), import or export, 
transport in interstate or foreign commerce in the course of commercial 
activity, or sell or offer for sale in interstate or foreign commerce 
any listed species. It also is illegal to possess, sell, deliver, 
carry, transport, or ship any such wildlife that has been taken 
illegally. Certain exceptions apply to agents of the Service and State 
conservation agencies.
    Permits may be issued to carry out otherwise prohibited activities 
involving threatened wildlife species under certain circumstances. 
Regulations governing permits are at 50 CFR 17.23. Such permits are 
available for scientific purposes, to enhance the propagation or 
survival of the species, and/or for incidental take in connection with 
otherwise lawful activities.
    It is the policy of the Service, published in the Federal Register 
on July 1, 1994 (59 FR 34272), to identify to the maximum extent 
practicable at the time a species is listed those activities that would 
or would not constitute a violation of section 9 of the Act. The intent 
of this policy is to increase public awareness of the effect of this 
listing on proposed and ongoing activities within the species' range. 
The Service believes that, based on the best available information, the 
following

[[Page 25832]]

actions will not result in a violation of section 9:
    (1) Road-kills or injuries caused by vehicles operated lawfully on 
designated public roads;
    (2) Light to moderate carefully managed livestock grazing that 
prevents or minimizes the excessive trampling of riparian and wetland 
habitat;
    (3) Possession of legally acquired California red-legged frogs;
    (4) Unintentional hooking of a frog or tadpole during otherwise 
lawful engagement in fishing, and;
    (5) Federally approved projects that involve activities such as, 
discharge of fill material, draining, ditching, tiling, pond 
construction stream channelization or diversion, or alteration of 
surface or ground water into or out of a wetland (i.e., due to roads, 
impoundments, discharge pipes, storm water detention basins, etc.), 
when such activity is conducted in accordance with any reasonable and 
prudent measures given by the Service in accordance with section 7 of 
the Act.
    Activities that the Service believes could potentially harm the 
California red-legged frog and result in ``take'', include, but are not 
limited to:
    (1) Unauthorized collecting or handling of the species;
    (2) Introduction of exotic species such as fish or other species of 
frogs directly into, or within dispersal distance of, known California 
red-legged frog habitat;
    (3) Unauthorized destruction/alteration of the species' habitat 
such as discharge of fill material, draining, ditching, tiling, pond 
construction, diversion or alteration of stream channels or surface or 
ground water flow into or out of a wetland (i.e., due to roads, 
impoundments, discharge pipes, storm water detention basins, etc.), 
operation of any vehicles within the stream channel;
    (4) Violation of discharge permits;
    (5) Burning, cutting or mowing of wetland or riparian vegetation, 
if conducted in an untimely or inappropriate manner (e.g., when 
California red-legged frogs would be killed or injured, or their 
occupied habitat would be degraded or rendered unsuitable);
    (6) Pesticide applications in violation of label restrictions;
    (7) Discharges or dumping of toxic chemicals, silt, or other 
pollutants (i.e., sewage, oil and gasoline) into waters, or riparian 
and upland habitats supporting the species;
    (8) Interstate and foreign commerce (commerce across State lines 
and international boundaries) and import/export (as discussed earlier 
in this section) without prior obtainment of an endangered species 
permit. Permits to conduct these activities are available for purposes 
of scientific research and enhancement of propagation or survival of 
the species.
    Questions regarding whether specific activities will constitute a 
violation of section 9 should be directed to the Field Supervisor of 
the Service's Sacramento Field Office (see ADDRESSES section). Requests 
for copies of the regulations concerning listed plants and general 
inquiries regarding prohibitions and permits may be addressed to the 
U.S. Fish and Wildlife Service, Ecological Services, Endangered Species 
Permits, 911 N.E. 11th Avenue, Portland, Oregon, 97232-4181 (telephone 
503/231-2063; facsimile 503/231-6243).

National Environmental Policy Act

    The Fish and Wildlife Service has determined that Environmental 
Assessments and Environmental Impact Statements, as defined under the 
authority of the National Environmental Policy Act of 1969, need not be 
prepared in connection with regulations adopted pursuant to section 
4(a) of the Endangered Species Act of 1973, as amended. A notice 
outlining the Service's reasons for this determination was published in 
the Federal Register on October 25, 1983 (48 FR 49244).

References Cited

    A complete list of all references cited herein is available upon 
request from the Field Supervisor, Sacramento Field Office (see 
ADDRESSES section).

Author

    The primary authors of this final rule are Karen J. Miller, Alison 
Willy, Sheila Larsen, and Steven Morey, Sacramento Field Office (see 
ADDRESSES section), telephone 916/978-4866.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, and Transportation.

Proposed Regulation Promulgation

    Accordingly, the Service hereby proposes to amend part 17, 
subchapter B of chapter I, title 50 of the Code of Federal Regulations, 
as set forth below:

PART 17--[AMENDED]

    1. The authority citation for part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
4201-4245; Pub. L. 99-625, 10080 Stat. 3500, unless otherwise noted.

    2. Section 17.11(h) is amended by adding the following, in 
alphabetical order under AMPHIBIANS, to the List of Endangered and 
Threatened Wildlife to read as follows:


Sec. 17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                      Species                                             Vertebrate population                                                         
----------------------------------------------------   Historic range      where endangered or       Status    When listed     Critical    Special rules
          Common name              Scientific name                              threatened                                     habitat                  
--------------------------------------------------------------------------------------------------------------------------------------------------------
           AMPHIBIANS                                                                                                                                   
                                                                                                                                                        
                                                                                                                                                        
                   *                  *                  *                  *                  *                  *                  *                  
Frog, California red-legged....  Rana aurora         U.S.A. (CA).......  Entire (excluding Del    T            ...........  NA             NA           
                                  draytonii.                              Norte, Humboldt,                                                              
                                                                          Trinity, & Mendocino                                                          
                                                                          Cos., CA; Glenn, Lake,                                                        
                                                                          & Sonoma Cos., CA,                                                            
                                                                          west of the Central                                                           
                                                                          Valley Hydrologic                                                             
                                                                          Basin; Sonoma & Marin                                                         
                                                                          Cos., CA, west & north                                                        
                                                                          of San Francisco Bay                                                          
                                                                          drainages and Walker                                                          
                                                                          Creek drainage; and                                                           
                                                                          NV).                                                                          
                                                                                                                                                        
                   *                  *                  *                  *                  *                  *                  *                  
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 25833]]


    Dated: May 17, 1996
Mollie H. Beattie,
Director, Fish and Wildlife Service.
[FR Doc. 96-12901 Filed 5-22-96; 8:45 am]
BILLING CODE 4310-55-P