Endangered and Threatened Wildlife and Plants; Revised Designation of Critical Habitat for the California Red-Legged Frog, 12816-12959 [2010-4656]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 75, Number 51 (Wednesday, March 17, 2010)]
[Rules and Regulations]
[Pages 12816-12959]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-4656]



[[Page 12815]]

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Part II





Fish and Wildlife Service





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50 CFR Part 17



Endangered and Threatened Wildlife and Plants: Revised Designation of 
Critical Habitat for California Red-Legged Frog; Final Rule

Federal Register / Vol. 75, No. 51 / Wednesday, March 17, 2010 / 
Rules and Regulations

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R8-ES-2009-0089]
[MO 92210-0-0009-B4]
RIN 1018-AV90


Endangered and Threatened Wildlife and Plants; Revised 
Designation of Critical Habitat for the California Red-Legged Frog

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), designate 
revised critical habitat for the California red-legged frog (Rana 
draytonii) under the Endangered Species Act of 1973, as amended (Act). 
In total, approximately 1,636,609 acres (ac) (662,312 hectares (ha)) of 
critical habitat in 27 California counties fall within the boundaries 
of the final revised critical habitat designation.

DATES: This rule becomes effective on April 16, 2010.

ADDRESSES: This final rule, final economic analysis, and maps are 
available on the Internet at https://www.regulations.gov and https://www.fws.gov/sacramento/. Comments and materials received, as well as 
supporting documentation used in preparing this final rule, are 
available for public inspection, by appointment, during normal business 
hours, at the U.S. Fish and Wildlife Service, Sacramento Fish and 
Wildlife Office, 2800 Cottage Way, Room W-2605, Sacramento, CA 95825; 
telephone 916-414-6600; or facsimile 916-414-6712.

FOR FURTHER INFORMATION CONTACT: For information on the revised 
designation in general and information about the revised designation in 
Alameda, Butte, Calaveras, Contra Costa, El Dorado, Kern, Kings, Marin, 
southern Mendocino, Merced, Napa, Nevada, Placer, San Joaquin, San 
Mateo, Santa Clara, Solano, Sonoma, Stanislaus, and Yuba Counties, 
contact Susan Moore, Field Supervisor or Arnold Roessler, Fish and 
Wildlife Biologist, U.S. Fish and Wildlife Service, Sacramento Fish and 
Wildlife Office, 2800 Cottage Way, Room W-2605, Sacramento, CA 95825; 
telephone 916-414-6600; or facsimile 916-414-6712. If you use a 
telecommunications device for the deaf (TDD), call the Federal 
Information Relay Service (FIRS) at 800-877-8339.
    For information about the revised designation in Los Angeles, 
Monterey, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz, and 
Ventura Counties, contact Diane Noda, Field Supervisor, Ventura Fish 
and Wildlife Office, U.S. Fish and Wildlife Service, 2394 Portola Road, 
Suite B, Ventura, CA 93003; telephone 805-644-1766; facsimile 805-644-
3958.
    For information about the exclusion of critical habitat in 
Riverside County, contact Jim Bartel, Field Supervisor, Carlsbad Fish 
and Wildlife Office, U.S. Fish and Wildlife Service, 6010 Hidden Valley 
Road, Suite 101, Carlsbad, CA 92011; telephone 760-431-9440; facsimile 
760-431-9624.
    For information about the revised designation in northern Mendocino 
County, contact Randy Brown, Acting Field Supervisor, Arcata Fish and 
Wildlife Office, U.S. Fish and Wildlife Service, 1655 Heindon Road, 
Arcata, CA 95521; telephone 707-822-7201; facsimile 707-822-8411.

SUPPLEMENTARY INFORMATION:

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat for the California red-legged frog 
in this final rule. For more information on the California red-legged 
frog and threats affecting the species, refer to the final listing rule 
published in the Federal Register on May 23, 1996 (61 FR 25813) and the 
recovery plan for the species (Service 2002, pp. 1-173).

Change in Nomenclature

    When we made the draft economic analysis of the proposed revised 
critical habitat for the California red-legged frog available on April 
28, 2009 (74 FR 19184), we proposed a nomenclature change to the 
California red-legged frog from Rana aurora draytonii to Rana draytonii 
and for that change to be published in the Code of Federal Regulations 
(CFR) when this rule became final. In this rule, we make that change 
and will now refer to the California red-legged frog by its accepted 
taxonomic name of Rana draytonii.

Species Description

    The California red-legged frog is the largest native frog in the 
western United States. It is endemic (native and restricted) to 
California and Baja California, Mexico, at elevations ranging from sea 
level to approximately 5,000 feet (ft) (1,500 meters (m)). Records of 
the California red-legged frog are known from Riverside County to 
Mendocino County along the Coast Range; from Calaveras County to Butte 
County in the Sierra Nevada; and in Baja California, Mexico (Grismer 
2002, p. 79; Fidenci 2004, pp. 27-29; Smith and Krofta 2005, pp. 4, 6; 
California Natural Diversity Database 2009 (CNDDB)). The California 
red-legged frog gains its name from the typically red or pink color of 
its posterior abdomen and hind legs. For a detailed description of the 
species, see the recovery plan for the California red-legged frog 
(Service 2002, pp. 1-173), references identified in the recovery plan, 
and information in previous Federal Register notices (April 13, 2006, 
71 FR 19244; March 13, 2001, 66 FR 14626; May 23, 1996, 61 FR 25813).

Life History

    During the breeding season, which typically runs from November 
through April, males call to females from the margins of ponds and slow 
streams (Jennings et al. 1992, p. 3). Mating most commonly occurs in 
February or March, but can vary depending on seasonal climatic 
patterns. The female lays a jellylike mass of 2,000 to 5,000 reddish 
brown eggs in the water attached to emergent vegetation, twigs, or 
other structure. The resulting tadpoles, which likely feed on algae 
(Dickman, 1968, pp. 1189-1190), typically require about 3 weeks to 
hatch, and another 11 to 20 weeks to metamorphose into juvenile frogs. 
Metamorphosis, therefore, typically occurs from July to September, 
although some tadpoles have been observed to delay metamorphosis until 
the following March or April (Bobzien et al. 2000, p. 13; Fellers et 
al. 2001, pp. 156-157). Adults are predominantly nocturnal, while 
juveniles can be active at any time of day (Hayes and Tennant 1985, p. 
604).

Habitat

    California red-legged frogs live in a Mediterranean climate, which 
brings about temporal and spatial changes in habitat quality. Almost 
the entire landscape, not just breeding ponds and streams, may become 
suitable habitat for the adults during periods of above average 
rainfall. Conversely, habitat that is suitable may be drastically 
reduced during periods of prolonged drought. Due to this variability, 
population sizes can vary widely from year to year. During years when 
aquatic habitat (ponds and streams) is abundant as a result of adequate 
rainfall, the California red-legged frog can produce large numbers of 
dispersing young, resulting in an increase in the number of occupied 
sites. In contrast, the California red-legged frog may temporarily 
disappear from an area during periods of extended drought. Therefore, 
it is essential to provide for sites that can be recolonized by

[[Page 12817]]

dispersing individuals (Semlitsch 2000, pp. 623, 624).
    Habitats used by the California red-legged frog typically change in 
extent and suitability in response to the dynamic nature of floodplain 
and fluvial processes (i.e., variable natural water flow and 
sedimentation regimes that create, modify, and eliminate deep pools, 
backwater areas, ponds, marshes, and other aquatic habitats). 
Rangewide, and even within local populations, the California red-legged 
frog uses a variety of areas, including aquatic, riparian, and upland 
habitats. They may complete their entire life cycle in a particular 
habitat (e.g., a pond is suitable for all life stages), or they may 
seek multiple habitat types depending on climatic conditions or 
distance between and availability of wetland and other suitably moist 
environments.
    Despite the California red-legged frog's ability to utilize 
multiple habitat types, there are certain habitat features they 
require. Most important is a breeding pond, or slow-flowing stream 
reach or deep pool within a stream with vegetation or other material to 
which egg masses may be attached. These areas must hold water long 
enough for tadpoles to complete their metamorphosis into juvenile frogs 
that can survive outside of water. Bobzien et al. (2000, p. 12) 
observed juveniles inhabiting a wide variety of habitats while adults 
primarily inhabited deep pools. They postulated that juveniles might 
segregate themselves away from adults to escape predation and 
competition (see Dispersal section below).
    In northern California, many California red-legged frog populations 
occupy artificially created wetland environments. Historically, as 
natural wetlands and streams were converted for agriculture, flood 
control, and urban development, the California red-legged frog 
colonized small artificial impoundments, or stock ponds, created by 
cattle ranchers for the purpose of providing water for their cattle. 
Our understanding of the role of stock ponds in the conservation of the 
California red-legged frog has evolved since listing. Without these 
stock ponds, the range of the California red-legged frog would be more 
limited in this region.
    Riparian and upland habitats adjacent to aquatic areas used by the 
California red-legged frog are essential in maintaining frog 
populations, and for protecting the appropriate hydrological, physical, 
and water quality conditions of the aquatic areas. Riparian habitat 
includes vegetation that grows along banks and in the floodplains of 
streams and adjacent to ponds and that is dependent on the bordering 
water source for survival. Adjacent uplands are marked by vegetation 
that is not dependent on a nearby supply of surface water. The 
California red-legged frog uses both riparian and upland habitats for 
foraging, shelter, cover, and non-dispersal movement (Service 2002, pp. 
14-15; Bulger et al. 2003, p. 87; Fellers and Kleeman 2007, p. 276). 
Bulger et al. (2003, pp. 85-95) studied the California red-legged 
frog's terrestrial activity in coastal forest and grassland habitats 
and recommends at least a 328-ft (100-m) buffer zone for protection of 
adjacent aquatic and upland habitat, as well as seasonal restrictions 
for activities within this zone. In a recent study also specific to the 
California red-legged frog, Fellers and Kleeman (2007, pp. 278-280) 
recommend establishing zones around breeding habitat, non-breeding 
habitat, and migration corridors that are sufficient to protect 
function of the amphibian habitat. However, Fellers and Kleeman (2007, 
p. 279) discourage setting specific distances for these zones due to 
differences in biological or site-specific requirements; they further 
state that any distances set for avoidance of upland habitat should be 
made on a case-by-case basis, taking into account the need to protect 
breeding and non-breeding habitat as well as any migration corridors. 
Without protecting and maintaining the upland areas surrounding 
breeding and non-breeding habitats the quality of the water feature may 
deteriorate to such an extent as to not support the California red-
legged frog.
    California red-legged frogs will disperse from their breeding 
habitat to forage and seek suitable upland and riparian habitat if 
aquatic habitat is not available. Tatarian (2004, p. 33) found the 
California red-legged frog inhabiting upland areas for 50 days at a 
distance of 302 ft (92 m) from aquatic habitat; Bulger et al. (2003, p. 
87-89) found that the species is capable of inhabiting upland habitats 
within 200 ft (60 m) of aquatic habitat for continuous durations 
exceeding 20 days; and Rathbun et al. (1993, p. 15) observed a 
California red-legged frog inhabiting upland riparian habitat at 
distances of up to 85 ft (26 m) for 65 days. These upland habitat areas 
used by the California red-legged frog include structure that provides 
shade, moisture, and cooler temperatures. This structure may be 
natural, such as the spaces under boulders or rocks and organic debris 
(e.g., downed trees or logs), or manmade, such as certain industrial 
debris and agricultural features (e.g., drains, watering troughs, 
abandoned sheds, or stacks of hay or other vegetation). The California 
red-legged frog will also use small mammal burrows and moist leaf 
litter as refugia (areas whose climate remains habitable when that of 
the surrounding areas has changed) (Rathbun et al. 1993, p. 15; 
Jennings and Hayes 1994, p. 64; Fellers and Kleeman 2005, p. 12).

Metapopulation Dynamics

    The life history and ecology of the California red-legged frog make 
it likely that this species has a metapopulation structure (Hanski and 
Gilpin 1991, pp. 3-16). A metapopulation is a set of breeding sites 
within an area, where typical migration from one local occurrence or 
breeding site to other areas containing suitable habitat is possible, 
but not routine. Within this rule we refer to these local occurrences 
as populations. The movement (i.e., dispersal) of frogs between areas 
containing suitable upland and aquatic habitats is restricted due to 
inhospitable conditions around and between areas of suitable habitats. 
Because many of the areas of suitable habitats may be small and support 
small numbers of frogs, local extinction of these small populations may 
be common. The persistence of a metapopulation depends on the combined 
dynamics of these local extinctions and the subsequent recolonization 
of these areas through dispersal (Hanski and Gilpin 1991, pp. 3-16; 
Hanski 1994, pp. 151-162). Maintaining corridors for dispersal between 
breeding and non-breeding habitat and between populations is essential 
in preserving the population structure of the California red-legged 
frog.

Dispersal

    Adult California red-legged frogs may disperse from breeding sites 
at any time of year depending on habitat availability and the 
environmental conditions of the aquatic habitat. In addition, a few 
frogs may disperse long distances in search of additional breeding or 
non-breeding habitat. Dispersing adult California red-legged frogs in 
northern Santa Cruz County traveled distances of 0.25 mile (mi) (0.4 
kilometers (km)) to more than 2.0 mi (3.2 km) without apparent regard 
to topography, vegetation type, or riparian corridors (Bulger et al. 
2003, p. 90). California red-legged frogs have also been tracked using 
radio telemetry in East Las Virgenes Creek, Ventura County, which is 
characterized by a well-defined creek and riparian zone with permanent 
deep pools and highly variable rainfall (Smith 2005, p. 1). The maximum 
distance moved in this study was 48 ft (15 m) (Smith 2005, p. 1). In 
contrast, California red-legged frog

[[Page 12818]]

movements in Santa Cruz County in similar habitat were found to be 
substantially less, with typical movements of 9 to 16 ft (3 to 5 m) 
from the water's edge. In a study in Marin County, 123 California red-
legged frogs were tracked using radio telemetry between 1997 and 2003 
at 8 different sites within the Point Reyes National Seashore and 
Golden Gate National Recreation Area (Fellers and Kleeman 2007, p. 
277). The habitat at the sites included permanent ponds, seasonal 
ponds, permanent marsh, and a seasonal seep. The majority of movement 
was small scale (less than 98 ft (30 m)) and considered non-dispersal. 
Movements of greater than 98 ft (30 m) occurred mostly during winter 
rain events; however, some movements did occur when the ponded habitat 
was almost dry (Fellers and Kleeman 2007, p. 279). The majority of 
California red-legged frogs dispersed less than 1,640 ft (500 m) away 
from breeding habitat, and the maximum dispersal distance recorded was 
1.7 mi (2.8 km) (Fellers and Kleeman 2007, pp. 279-280). The study 
concluded that most California red-legged frogs move away from breeding 
sites, but only a few disperse farther than the nearest non-breeding 
habitat, and that the distance moved is highly dependent on site 
conditions and local landscapes (Fellers and Kleeman 2007, p. 284). The 
study also concluded that, by establishing a generic dispersal distance 
for the species, we may select for sedentary frogs and thus lose those 
individuals that disperse farthest and reach other distant breeding 
sites. This selection may thereby decrease genetic exchange and 
diversity (Fellers and Kleeman 2007, p. 285). As a result the authors 
recommend that the average dispersal or migration distances identified 
in the study not be used; site conditions should dictate the area 
needed for the species.
    Newly metamorphosed juveniles tend to disperse short distances 
initially from July through September, and then move farther away from 
the breeding habitat during warm rain events (Jennings 2000, p. 1). 
Additionally, and for reasons that are unclear, juveniles tend to 
disperse away from aquatic habitat occupied by adults. Juvenile 
dispersal is essential for recolonizing temporarily extirpated habitat 
and for preventing genetic isolation because juveniles disperse in more 
directions, and for longer distances, than do migrating adults (Wright 
1999, p. 2; Bulger et al. 2003, p. 94). Dispersal habitat for juveniles 
can be any habitat that provides sheltering vegetation and scattered 
wetlands or streams, including forested areas, nonnative grasslands, 
croplands, and pastures. It is unlikely that juveniles disperse through 
urbanized or suburban areas, suburban developments, or areas separated 
from breeding habitat by impassible barriers. Juveniles dispersing 
along riparian corridors may have higher survivorship, as sheltering 
vegetation and suitable aquatic habitat are both more common in such 
corridors (Jennings 2000, p. 1). Finally, juvenile California red-
legged frogs appear to have less strict requirements for aquatic 
habitat than adults, and tend to segregate away from adults in water 
bodies that are shallower or faster moving than those typically used 
for breeding (Hayes and Jennings 1988, p. 147; Bobzien 2000, p. 1; M. 
Jennings 2000, p. 1).

Dispersal Barriers

    Impassible barriers that impact dispersal of the California red-
legged frog include wide or fast-flowing rivers and streams, lakes 
greater than 50 ac (20 ha), and heavily traveled roads (such as 
highways or freeways) without underpasses or culverts (Reh and Seitz 
1990, pp. 247, 248; Fahrig et al. 1995, pp. 179-181). Passable roadways 
that are heavily used by vehicles may also result in a high rate of 
mortality for California red-legged frog adults and juveniles, and 
other amphibians, thereby limiting dispersal capabilities (Glista et 
al. 2008, pp. 81-82).
    The long-term probability of the survival and recovery of the 
California red-legged frog is dependent upon the protection of existing 
breeding habitat and associated uplands (Fellers and Kleeman 2005, pp. 
1, 17-18), the movement of individuals between aquatic habitat patches, 
and the ability to recolonize newly created or vacated habitats. 
Recolonization of vacant habitat patches, which is vital to maintaining 
the California red-legged frog populations and the recovery of this 
species, is dependent upon landscape characteristics, including 
appropriate distances between suitable breeding and non-breeding 
aquatic habitat, and limited fragmentation of interconnecting habitat 
(Vos and Chardon 1998, pp. 44, 53-56). For this rule, we based our 
designation of critical habitat on areas of high-quality habitat that 
we determined provide for persistence of California red-legged frog 
populations and allow for dispersal within, and in most cases between, 
populations. We did not designate areas subject to anthropogenic 
activities (e.g., urban development) or those that were fragmented or 
unlikely to be restorable (poor quality habitat) unless it was 
determined that these areas were unique for the species (for more 
information, see the Criteria Used to Identify Critical Habitat section 
below).

Previous Federal Action

    On July 20, 2007, we announced that we would review the April 13, 
2006, final rule (published at 71 FR 19243) designating critical 
habitat for the California red-legged frog under the Act (16 U.S.C. 
1531 et seq.)(Service 2007a, pp. 1-2), after questions were raised 
about the integrity of scientific information used and whether the 
decision made was consistent with the appropriate legal standards. 
Based on our review of the 2006 final critical habitat designation, we 
determined it was necessary to revise the critical habitat; however, no 
specific dates for completing such revision were established. 
Subsequently, the Center for Biological Diversity filed a complaint in 
the U.S. District Court for the Northern District of California on 
December 12, 2007, challenging our designation of critical habitat for 
the California red-legged frog (Center for Biological Diversity v. 
Kempthorne, et al., Case No. C-07-6404-WHA). The court entered a 
consent decree on April 2, 2008, requiring a proposed revised critical 
habitat rule to be submitted to the Federal Register by August 29, 
2008, and a final revised critical habitat designation to be submitted 
to the Federal Register by August 31, 2009. On September 16, 2008, we 
published in the Federal Register a proposed revised rule to designate 
critical habitat for the California red-legged frog (73 FR 53491).
    We published a document in the Federal Register on April 28, 2009 
(74 FR 19184): (1) Reopening the public comment period on the revised 
proposed rule to designate critical habitat for the California red-
legged frog (73 FR 53491); (2) announcing the availability of a draft 
economic analysis (DEA) of the proposed rule to revise critical 
habitat; (3) proposing boundary changes to Unit MEN-1 to better reflect 
the occupied habitat for the species; and (4) proposing a change to the 
taxonomic nomenclature for the species. The public comment period 
closed on May 28, 2009.
    The comments received on our DEA (IEc 2009a) during the April 28 to 
May 28, 2009, public comment period led us to revise the DEA (IEc 
2009b). To allow public comment on the revised DEA, an extension to the 
publication deadline of the final determination of critical habitat was 
required. On August 31, 2009, a consent decree was signed by the court 
extending the deadline for the final revised designation of critical 
habitat for the California red-legged frog

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to March 1, 2010. On October 8, 2009, we published a document in the 
Federal Register (74 FR 51825) announcing the availability of the 
revised DEA. We reopened the comment period for an additional 30 days 
to allow all interested parties an opportunity to comment 
simultaneously on the proposed revision of critical habitat and the 
associated revised DEA. This rule represents our final revised 
designation of critical habitat in compliance with the court order.

Summary of Comments and Recommendations

    We requested written comments from the public and peer reviewers 
during three comment periods on the proposed rule to revise critical 
habitat for the California red-legged frog. The first comment period 
opened September 16, 2008 (73 FR 53491), and closed November 17, 2008. 
The second comment period opened April 28, 2009 (74 FR 19184), and 
closed May 28, 2009. The third comment period opened October 8, 2009 
(74 FR 51825), and closed November 9, 2009. During these three comment 
periods, we contacted appropriate Federal, State, and local agencies; 
scientific organizations; and other interested parties and invited them 
to comment on the proposed rule to revise critical habitat for the 
California red-legged frog and the associated DEA. We did not receive 
any requests for public hearings during these comment periods. We did, 
however, receive a request to attend a public meeting in San Andreas, 
California held on October 30, 2008. During the public meeting, we 
provided information and answered questions regarding the designation 
and exclusion processes.
    During the three comment periods we received a total of 113 public 
comments directly addressing the proposed revision of critical habitat. 
In addition we received four responses from peer reviewers we solicited 
to comment on the proposed revised designation. During the first 
comment period we received 80 comments directly addressing the proposed 
revision of critical habitat for the California red-legged frog. During 
the second comment period, we received 19 new comments directly 
addressing the proposed revision of critical habitat for the California 
red-legged frog and the DEA; and during the third comment period we 
received an additional 12 comments addressing the proposed revision of 
critical habitat for the California red-legged frog and the DEA.

Peer Review

    In accordance with our policy published in the Federal Register on 
July 1, 1994 (59 FR 34270), we solicited expert opinions from five 
knowledgeable individuals with scientific expertise that included 
familiarity with the California red-legged frog, the geographic region 
in which the species occurs, and conservation biology principles. We 
received responses from four of the peer reviewers.
    We reviewed all comments received from the peer reviewers and the 
public for substantive issues and new information regarding critical 
habitat for the California red-legged frog. These comments are 
addressed below and incorporated into the final rule as appropriate.

Peer Review Comments

    Comment (1): One peer reviewer stated that the Service used a 
reasonable approach in determining the critical habitat boundaries for 
the California red-legged frog by looking at the core recovery areas as 
identified in the 2002 recovery plan. The reviewer also said the 
Service appropriately evaluated the metapopulation dynamics, unoccupied 
areas, dispersal, and connectivity of habitat for the California red-
legged frog. The peer reviewer concurred with our proposal to raise the 
California red-legged frog to full species level. However, the peer 
reviewer went on to say that the current designation represents only a 
relatively small proportion of the historic geographic range of the 
species and that it is unknown if the California red-legged frog can 
survive long-term in such a reduced range.
    Response: In this current revised designation, we acknowledge that 
we did not include all areas where the California red-legged frog 
occurs and that areas outside the designation either: (1) Do not 
contain essential habitat features, or (2) are not essential to the 
conservation of the species. We believe it is important, however, to 
note that critical habitat designation is a different process than 
development of a long-term management plan such as a recovery plan. A 
critical habitat designation is a specific regulatory action that 
defines particular areas as critical habitat in accordance with the 
statutory definition. Our revised methodology incorporates new 
information to best identify areas that meet the definition of critical 
habitat. As a result, the final revised critical habitat designation 
does not include, for example, all areas that the 2002 recovery plan 
identified as necessary for the conservation of the California red-
legged frog. Therefore, we believe this final revised critical habitat 
designation more precisely maps the essential physical and biological 
features that occur within the geographical area occupied by the 
California red-legged frog at the time of listing, and includes those 
areas containing the most suitable habitat for use by the frog.
    Comment (2): One peer reviewer stated that, although the review of 
dispersal capabilities of the frog were well discussed, it should be 
noted that the studies of dispersal capabilities rely on relatively few 
individuals and likely miss the relatively rare long-range distance 
dispersers. The peer reviewer also mentioned that the Service did not 
discuss whether dispersal events actually result in geneflow between 
metapopulations.
    Response: We believe we have reviewed the most recent scientific 
information on frog dispersal capabilities of the California red-legged 
frog and have used this information appropriately in our designation of 
critical habitat. We acknowledge that the California red-legged frog 
may disperse beyond the dispersal distance of 1 mi (1.6 km) identified 
in the designation (Bulger et al. 1999, p. 11; Fellers and Kleeman 
2007, pp. 279-280). However, as stated by the peer reviewer, these long 
distance movements are rare and represent the exception to dispersal 
events for the species. In addition, the designation is not based 
solely on the 1-mi (1.6-km) dispersal distance but is based on habitat 
features and watershed boundaries that we have determined are connected 
to those areas where the California red-legged frog occurs. We have, 
therefore, included areas in this designation beyond the strict 1-mi 
(1.6-km) distance. We are currently unaware of any completed genetic 
studies regarding the genetic exchange between frog populations and at 
what distance this genetic exchange is considered to be limited and not 
important for the species. Our methodology to include the habitat areas 
surrounding known populations, as well as to connect adjacent 
populations together into discernable units, most likely allows for 
such genetic exchange.
    Comment (3): One peer reviewer applauded our decision to reevaluate 
the 2006 designation, but stated that the Service should incorporate 
the 2001 designation into our analysis and remove areas identified in 
the 2001 designation only if the Service has justifiable scientific 
information or if it can be shown that the 2001 designation

[[Page 12820]]

was inaccurate. The same peer reviewer mentioned that the Service 
should review the units within Sonoma County to ensure that they 
include all uplands within 1 mi (1.6 km). The peer reviewer also stated 
that the entire Sonoma Mountain area from Annadel State Park to Sears 
Point/Highway 37 area should be designated as this area has more than 
15 records of the California red-legged frog, most of which are 
breeding sites. The peer reviewer went on to mention that Unit SON-3 
should be connected to Unit MRN-2 in Marin County to provide 
connectivity between units based on habitat availability and recent 
documentation of new California red-legged frog records within the 
area.
    Response: We agree with the peer reviewer that habitat connectivity 
is important to allow for movement between California red-legged frog 
populations and to maintain genetic variation. We are aware of the 
extensive amount of scientific evidence illustrating the importance of 
habitat connectivity, and we considered this information during the 
development of this critical habitat designation. We acknowledge that 
areas potentially providing connectivity between units were included in 
the 2001 critical habitat designation; however, based on our 
reevaluation of the data available at the time of the 2001 designation, 
data obtained since, and our revised methodology for delineating 
critical habitat, we find that those areas do not meet the definition 
of critical habitat because the available data do not identify specific 
areas between these units that contain the physical or biological 
features essential to the conservation of the California red-legged 
frog. The 2001 designation was based on large-scale watershed 
boundaries and not the local watershed boundaries in this designation. 
We believe the use of the local watershed boundaries is more 
appropriate based on dispersal capabilities of the species and the 
information known on occupancy. The area surrounding the Sonoma and 
Marin County units includes developed areas, dairies, and ranchland. We 
evaluated the areas within the 1-mi (1.6-km) distance from the Sonoma 
and Marin County occurrence records and potential breeding habitats and 
determined that for the most part these areas, although likely used by 
the frog, do not meet our criteria established for this designation. We 
focused our designation to encompass areas that support viable (self-
sustaining or increasing) populations, areas that represent portions of 
the geographic extent of the species within the core areas identified 
in the 2002 recovery plan, and any other unique habitats. We did not 
include all the areas occupied by the California red-legged frog. For 
more information on our criteria for designating critical habitat for 
the California red-legged frog see the Criteria Used To Identify 
Critical Habitat section below.
    Comment (4): One peer reviewer commented on Unit MEN-1 (as 
identified in the September 2008 proposed revised designation), saying 
that it includes northern red-legged frogs (Rana aurora) or hybrids 
between the northern red-legged frog and the California red-legged 
frog. The peer reviewer stated that hybrids between the two species 
occur as far south as Manchester State Beach, but that the exact zone 
of hybridization and its importance to either species is unknown.
    Response: As stated in our April 28, 2009, Federal Register 
publication announcing the availability of the draft economic analysis 
(74 FR 19184), we revised Unit MEN-1 to better reflect new species 
occurrence data within the area and the habitat surrounding those 
records. On further review of the unit, we further adjusted the 
boundaries to include only known California red-legged frog records and 
not hybrid northern red-legged frog records. The unit currently 
includes the habitat from Manchester State Beach south to Riverside 
Road. Unit MEN-1 represents the northern extent of the California red-
legged frog within the North Coast of California and likely represents 
a unique genetic component of the species.
    Comment (5): One peer reviewer concluded that it is unclear whether 
the Service considered climate change in the current designation and 
what effects climate change may have on the California red-legged 
frog's habitat in the future.
    Response: We acknowledge that climate change may alter the 
suitability of the California red-legged frog's habitat in the future. 
However, we are required to designate critical habitat based upon the 
best available scientific data at the time that we finalize the 
designation. For species like the California red-legged frog, we 
conclude relatively higher elevation and moister habitat is likely to 
become increasingly important in the face of climate changes. The 
designated critical habitat units include areas distributed across the 
species range from southern California to Butte and Mendocino County in 
northern California and vary from coastal sea-level locations to 
interior Coast Range areas and higher elevation locations in the Sierra 
Nevada Mountains. The variability of environmental conditions at 
locations across the range of the species would likely become more 
important to the extent that California red-legged frog distribution 
and habitat may shift upward in elevation and northward in distribution 
as temperatures increase and precipitation becomes more variable due to 
climate change. However, at this point in time, reliable projections of 
future climatic conditions and how those conditions may affect the 
California red-legged frog's distribution and habitat in California are 
not available. Consequently, we find it appropriate to designate 
critical habitat for the California red-legged frog in areas occupied 
by the species that currently contain the physical and biological 
features or the areas essential to the conservation of the California 
red-legged. Revisions to the critical habitat designation may be 
necessary in the future to accommodate shifts in the occupied range of 
the California red-legged frog.

Comments from Department of Defense

    Comment (6): The Department of The Army, the National Guard Bureau, 
and the California Army National Guard commented that we should exclude 
Camp San Luis Obispo (CSLO) from critical habitat designation for the 
California red-legged frog under section 4(b)(2) of the Act, for 
reasons including national security and economic impacts.
    Response: The Secretary has determined to exercise his discretion 
under section 4(b)(2) of the Act to exclude lands at CSLO from this 
final designation due to potential impacts on national security (see 
Application of Section 4(b)(2) - Impacts to National Security section).
    Comment (7): The Department of the Air Force commented that we 
should exclude Vandenberg Air Force Base (VAFB) from critical habitat 
designation for the California red-legged frog under section 4(b)(2) of 
the Act, for reasons including impacts on national security, and under 
section 4(a)(3)(B)(i) of the Act, for operating under a draft 
Integrated Natural Resources Management Plan (INRMP).
    Response: The Secretary has determined to exercise his discretion 
under section 4(b)(2) of the Act to exclude lands at VAFB from this 
final designation due to potential impacts on national security (see 
Application of Section 4(b)(2) - Impacts to National Security section).

[[Page 12821]]

Public Comments

Comments Related to Site-Specific Areas or Issues

    Comment (8): Four commenters opposed designation of parts or all of 
proposed Unit CAL-1 because they believe that the majority of the area 
constitutes poor habitat for the California red-legged frog. Six 
commenters stated that most of the area is too dry for the California 
red-legged frog to occur, and that most ponds and streams are dry for 4 
to 5 months of the year. Two commenters noted that perennial ponds and 
streams support populations of predatory fish and bullfrogs and would 
not support California red-legged frogs.
    Response: We consider Unit CAL-1 to contain high-quality habitat 
because it contains the physical and biological features essential to 
the conservation of the species and has not been subject to 
fragmentation due to development. The habitat within the unit includes 
areas of aquatic breeding habitat that hold water for a minimum of 20 
weeks in all but the driest years, areas of non-breeding aquatic 
habitat, and areas of upland and dispersal habitat within 1 mi (1.6 km) 
of aquatic habitat. The California red-legged frog is adapted to dry 
environments. The drying of watercourses and ponds is beneficial in 
that it precludes the use of these habitats by bullfrogs and predatory 
fish. While water bodies free of bullfrogs and predatory fish would be 
optimal, the California red-legged frog can persist in the presence of 
both of these predators under specific conditions such as occur within 
Unit CAL-1. In aquatic systems subject to seasonal drying, it may be 
difficult for bullfrogs to become established. As discussed in the 
background section of the proposed revised critical habitat rule, 
Doubledee et al. (2003, pp. 424-438) studied the relationship between 
bullfrogs and California red-legged frog persistence. That study showed 
that bullfrogs and California red-legged frogs can coexist and persist 
under certain natural and managed regimes. Additionally, periodic 
drying may prevent nonnative warm water fish from becoming established 
as well. Alvarez et al. (2003, pp. 9-12) presented evidence that 
nonnative predatory fish can have a significant effect on juvenile 
California red-legged frog survival in ponds where they co-occur. Of 90 
ponds surveyed in the Los Vaqueros watershed in Contra Costa County, 7 
were found to have nonnative fish. Over 3 years, one or more ponds with 
nonnative fish were repeatedly drained, and all fish were exhaustively 
removed. Compared to surveys conducted before fish removal, surveys 
conducted after fish removal and pond recharge showed juvenile and 
adult California red-legged frog abundance increased dramatically. This 
suggests a strong link between nonnative fish presence and decreased 
California red-legged frog survival. The California red-legged frog is 
adapted to the drying of its aquatic habitat. Moreover, this drying 
assists the frog by eliminating potential predators and competition for 
resources.
    Comment (9): Nine commenters stated that the data on the California 
red-legged frog population in Unit CAL-1 are not sufficient to justify 
critical habitat designation throughout the unit. Five of these claimed 
there is no information to indicate the population still exists, while 
others noted they had never seen such frogs within the unit despite 
long residence and experience with catching bullfrogs in the area. One 
commenter questioned the validity of California red-legged frog 
occurrence as being natural and suggested that the California red-
legged frog was potentially introduced to the area. One commenter asked 
why the unit extends 2.2 mi (3.5 km) from the frog population despite 
our PCEs, which restrict the extent of upland and dispersal habitat. 
Another commenter specifically noted the importance of the California 
red-legged frog population at Unit CAL-1 on the grounds that it is one 
of only six remaining in the Sierra foothills.
    Response: We consider this population to be important to the 
conservation of the California red-legged frog because it is one of six 
remaining populations in the Sierra Nevada foothills, which is a 
historical portion of the species' range (Service 2002, p. 5). Such 
peripheral populations may also have unusual genetic characteristics 
that could prove useful in maintaining the genetic variability of the 
species (Gilpin and Soule 1986, p. 32). Species that are able to 
maintain their genetic variability can more easily adapt to 
environmental changes and therefore be less prone to extirpation or 
extinction. The California Natural Diversity Database (2009) indicates 
the California red-legged frog population was seen relatively recently, 
and we have no evidence to suggest it is no longer extant. Information 
available to the Service confirms the species' presence as recently as 
October 2008. We consider repeated and comprehensive surveys by trained 
personnel to be necessary to conclude a population has been extirpated. 
Based on the information available on the sighting and circumstances 
surrounding the discovery of California red-legged frogs, we have no 
reason to question the validity of the record as being a natural 
occurrence. Also, regardless of whether the population of California 
red-legged frogs was introduced to the area, it is still considered a 
listed species under the Act and still receives the protections of a 
listed entity.
    The size of Unit CAL-1 reflects our methodology and criteria for 
mapping the critical habitat units. We based the proposed boundaries of 
the unit on the local watershed boundaries where California red-legged 
frogs have been sighted. However, in response to public comments and 
site visits by Service staff, we revised the boundaries of the unit to 
better reflect the available habitat within the area and the locations 
used by the California red-legged frog. As a result, we revised the 
extent of the unit and removed those areas that we determined do not 
contain the physical and biological features essential for conservation 
of the California red-legged frog.
    Comment (10): Two commenters noted that Unit CAL-1 is outside the 
core recovery area identified by the recovery plan (Service 2002, p. 
132). One additional commenter asked if surveys had established local 
salinity or temperature levels, or if a habitat suitability index had 
been established for the area.
    Response: We recognize this designation is different than what is 
outlined as essential habitat in the 2002 recovery plan (which largely 
adopted the boundary delineated in the 2001 critical habitat 
designation (66 FR 14625; March 13, 2001)). While we believe the 2001 
designation and the 2002 recovery plan are important for determining 
the extent of habitat use by the California red-legged frog, we have 
significantly more data available today than when we finalized 2001 
critical habitat designation and the 2002 Recovery Plan. We have 
utilized the currently available data to more precisely identify areas 
meeting the definition of critical habitat, in particular, areas 
related to connectivity. We include such areas in this designation 
where the data support the determination that such areas contain the 
physical and biological features essential to the conservation of the 
species. We believe it is important to note that critical habitat 
designation is a different process than development of a recovery plan. 
A critical habitat designation is a specific regulatory action that 
defines specific areas as critical habitat in accordance with the 
statutory definition. A recovery plan is a guidance document, developed 
in cooperation with partners, that provides a roadmap with detailed 
site-specific

[[Page 12822]]

management actions to help conserve listed species and their 
ecosystems. The term ``essential,'' as used in the recovery plan, is 
not necessarily used in the same manner as it is used in the definition 
of critical habitat (section 3(5) of the Act). The recovery plan 
provides important information about the species and the actions that 
are needed to bring about its recovery, while critical habitat 
identifies specific areas that are essential for the species' 
conservation. In addition, although Unit CAL-1 is outside the core 
recovery area established for Calaveras County by the recovery plan, 
that plan was completed in 2002, and could not account for the 
discovery of the California red-legged frog population in 2003.
    We have not conducted water quality surveys or developed habitat 
suitability index models for proposed critical habitat units. The 
extent of the designation would make these efforts impractical. We have 
determined that specific water salinity or other water monitoring 
aspects are not necessary because the California red-legged frog is 
recently confirmed to be occupying the area and the landowner maintains 
suitable habitat as a result of agreements with the Service. Based on 
the best scientific information available to us at this time, we 
believe that the area within Unit CAL-1 that we are designating as 
critical habitat for the California red-legged frog is appropriate and 
necessary.
    Comment (11): Five commenters indicated we could do more for 
California red-legged frog conservation by pursuing conservation 
agreements with landowners in the vicinity of Unit CAL-1, rather than 
by designating the unit. Thirty-five signatories of a form letter 
indicated they would be less likely to participate in conservation 
partnership projects with us in the future if we designate this unit.
    Response: Although we are aware that the establishment of 
partnerships with private landowners is essential to the conservation 
of many species including the California red-legged frog, we are not 
able to forego the designation of critical habitat based on the 
possibility of establishing conservation partnerships in the future. We 
must adequately weigh the benefits, pursuant to section 4(b)(2) of the 
Act, for conserving the California red-legged frog and its habitat from 
the partnerships and resulting conservation programs and plans relative 
to the regulatory benefits of designating the specific areas as 
critical habitat. Despite our exclusion of this unit in our 2006 final 
critical habitat designation (71 FR 19243), landowners wishing to build 
partnerships have not approached us despite our efforts to establish 
such willing partnerships with landowners. It was not until after we 
published our proposed revised designation on September 16, 2008 (73 FR 
53491), that landowners within Unit CAL-1 contacted us regarding 
developing potential partnerships. On October 30, 2008, we attended a 
public meeting in San Andreas, California, to provide information on 
the proposed revised designation, and we were subsequently approached 
by several landowners interested in forming partnerships and working 
with the Service on conservation measures for the California red-legged 
frog on their private property. However, due to the short court-ordered 
timeframe of this action, we have not been able to finalize any 
agreements or management plans for the frog or its habitat with these 
landowners. We have, however, been able to meet with these landowners 
during site visits to discuss potential habitat restoration activities 
or other conservation measures for the California red-legged frog on 
their properties. We will continue to work with local landowners and 
seek new partnerships regarding the frog in the future.
    Comment (12): Ten commenters, and an additional 35 signatories of a 
form letter, requested exclusion of Unit CAL-1 under section 4(b)(2) of 
the Act. They stated that the benefits of such exclusion would outweigh 
the benefits of designation for the following reasons:
    (1) Routine grazing practices benefit the California red-legged 
frog, and designation would increase the liabilities on such practices;
    (2) Designation would trigger review of Farm Bill conservation 
grant projects under section 7 of the Act, thereby decreasing the 
incentive to apply for such grants;
    (3) Designation negatively impacts landowners but provides little 
benefit to the species;
    (4) Much of the land in the unit is already protected by incentives 
under the Williamson Act to keep the land in agricultural uses;
    (5) Designation could impact water deliveries to farmers and 
interfere with road repair, the clearing of logjams from streams, and 
other infrastructure maintenance;
    (6) Designation would limit development and the planting of crops; 
and
    (7) Designation would lower property values.
    Response: We finalized a special rule under section 4(d) of the Act 
for the California red-legged frog in 2006 (71 FR 19243; April 13, 
2006) that exempts routine ranching operations from the take 
prohibitions of the Act. We recognize livestock ranching as a dynamic 
process, which requires the ability to adapt to changing environmental 
and economic conditions. However, many of the activities essential to 
successful ranching are considered routine, and are undertaken at 
various times and places throughout the year as need dictates. Although 
the 4(d) special rule is not intended to provide a comprehensive list 
of those ranching activities considered routine, some examples include: 
maintenance of stock ponds; fence construction for grazing management; 
planting, harvest, and rotation of unirrigated forage crops; 
maintenance and construction of corrals, ranch buildings, and roads; 
discing of field sections for fire prevention management; control of 
noxious weeds by prescribed fire or by herbicides; placement of mineral 
supplements; and rodent control. The final version of the 4(d) special 
rule includes an expanded definition of routine ranching practices and 
incorporates additional activities we believe are consistent with the 
conservation of the California red-legged frog. These activities are 
those that may provide conservation benefits to the California red-
legged frog. The ranching activities listed in the 2006 final critical 
habitat designation (71 FR 19243; April 13, 2006) are examples of 
practices that we understand are routine to managing an active ranching 
operation. Our intention is not to limit activities that may be 
necessary to the operation of a ranch. As a result of implementing the 
4(d) special rule, we are unaware of any increased liabilities 
associated with ranching operations having a higher liability than 
those areas not dedicated to ranching.
    The final economic analysis (EA) prepared for this designation 
calculates the impact of critical habitat on agricultural land values 
by measuring its effect on the likelihood and profitability of 
residential and commercial development. One comment stated that farm 
subsidies may trigger a consultation under section 7 of the Act and 
that these costs should be included in the final EA. This linkage is 
speculative, and there is no instance of a farm subsidy being used as 
the basis for a consultation with the Service. Further, activities 
including discing, plowing, irrigation, chemical application, 
harvesting, and others that are part of normal agricultural operations 
are also unlikely to trigger a section 7 consultation. Incremental

[[Page 12823]]

costs to farming operations may result from construction of stream 
crossings, water diversion, and sediment and debris removal; these 
costs are discussed in the final economic analysis. Existing regulatory 
mechanisms such as the California Land Conservation Act of 1965 
(commonly referred to as the Williamson Act) may afford some regulatory 
protection to the California red-legged frog. However, the protection 
afforded by these regulations does not sufficiently protect the species 
to such an extent that it would warrant consideration for exclusion 
under section 4(b)(2) of the Act. The Williamson Act is a voluntary 
contract between participating landowners and cities or counties to 
voluntarily restrict land use to agricultural or open-space uses. The 
term of the contracts is a minimum of 10 years, and the landowner may 
petition to cancel the contract. Also the conditions of the contracts 
vary by city or county or even landowner and would not specifically 
identify conservation measures for the frog. Therefore, as a result of 
implementing the 4(d) special rule, our review of the Williamson Act 
conditions, and review of the economic costs associated with Unit CAL-
1, we have determined that the measures identified by the commenters do 
not warrant further consideration for our exclusion of the unit under 
section 4(b)(2) of the Act.
    Comment (13): Five commenters asked us to exclude agricultural land 
in Marin County under section 4(b)(2) of the Act. They stated that the 
benefits of such exclusion would outweigh the benefits of designation 
for the following reasons:
    (1) Routine grazing practices benefit the frog, and designation 
would increase the liabilities on such practices;
    (2) Designation would trigger review of Farm Bill conservation 
grant projects under section 7 of the Act, thereby decreasing the 
incentive to apply for such grants;
    (3) Designation negatively impacts landowners economically but 
provides little benefit to the species;
    (4) Designation could impact water deliveries to farmers and 
interfere with road repair, the clearing of logjams from streams, and 
other infrastructure maintenance; and
    (5) Designation would lower property values.
    Response: See our response to Comment (12) above.
    Comment (14): One commenter noted that we provided incorrect area 
estimates for Federal and private lands in proposed unit ELD-1. The 
commenter also stated that designation of private lands within the 
proposed unit would be inconsistent with the El Dorado County General 
Plan.
    Response: We have revised the land ownership for Unit ELD-1 to 
correctly reflect the landownership within the unit. When designating 
critical habitat, we base our designation on the essential habitat 
features required by the species. When exercising our discretion to 
exclude areas from critical habitat under section 4(b)(2) of the Act, 
we must weigh the benefits of designating against the benefits of not 
designating critical habitat. Such exclusions are usually based on 
finalized management plans, habitat conservation plans, or other 
documents and not on local general plans unless there is a high degree 
of certainty that conservation measures will take place for a 
particular species and that those measures are more beneficial than the 
designation of critical habitat. We have reviewed El Dorado County's 
general plan and found no measures specific to the conservation of the 
California red-legged frog or its habitat. The County identifies 
numerous goals in the Conservation and Open Space Element within its 
general plan; however, no specific measures with respect to the 
conservation of the primary constituent elements for the California 
red-legged frog are mentioned. While we value El Dorado County's 
voluntary agreement in the interagency protection of Spivey Pond, based 
on the general plan, we have not exercised our discretion to exclude El 
Dorado County in its entirety from designated critical habitat. We 
have, however, exercised our discretion to exclude those areas managed 
by the Bureau of Land Management (BLM) at Spivey Pond in El Dorado 
County based on an interagency land use management plan (see 
Application of Section 4(b)(2) of the Act section below).
    Comment (15): One commenter stated that we should include 
downstream portions of Weber Creek in proposed unit ELD-1, as that area 
contains habitat elements essential to the conservation of the species.
    Response: We used the best scientific information available in 
determining those areas that contain the physical and biological 
features essential for the California red-legged frog and that we 
therefore proposed as critical habitat. During our determination 
process, we considered several criteria in the selection of areas that 
contain the features essential for the conservation of the California 
red-legged frog. We did not include all available habitat or all areas 
where frogs are located within the designation. Although the Weber 
Creek area may contain some primary constituent elements, we believe 
the arrangement and quantity of those features may not be adequate. For 
more information, please see the Criteria Used to Identify Critical 
Habitat section below.
    Comment (16): One commenter asked us to remove a specific property 
from SOL-2 on the basis that some of it is too dry to constitute good 
habitat, while the rest is not within 1 mi (1.6 km) of a known 
occurrence, nor is it uplands connecting several occurrences. The 
commenter also requested exclusion from the critical habitat 
designation on economic grounds, arguing that designation would prevent 
conversion of over 900 ac (364 ha) of land suitable for winegrowing, 
resulting in a cost of $3.5 million in gross revenue. Another commenter 
stated that we appropriately designated land within Units SOL-1, SOL-2, 
and SOL-3 in that designation of this land will assist in conserving 
the California red-legged frog and its habitat. The commenter suggested 
that additional areas adjacent to Unit SOL-1 be part of the designation 
including areas along Highway 680 and adjacent to Suisun Marsh in 
Solano County. The commenter also stated that the Service should ensure 
that ``these critical habitat designations not be overridden by 
presumed `public' benefits'' for other uses such as wind energy or 
electrical transmission lines.
    Response: We based this final revised critical habitat designation 
on California red-legged frog occurrence records, habitat surrounding 
those localities, and local watershed boundaries. The occurrence 
records within Unit SOL-2 are associated with the drainages in the 
Jameson Canyon area. Our determination of the unit boundaries focused 
on incorporating not only the occurrence records but also any adjacent 
habitat up to the local watershed boundary as long as we could 
determine that the habitat within the watershed was reasonably 
connected. In some cases where the records were isolated and habitat 
not extensive, we used the 1-mi (1.6-km) dispersal distance to 
determine the extent of the designation. In other cases where the 
habitat was similar or included adjacent water courses within the 
dispersal distance of the California red-legged frog, we looked at the 
habitat and watershed boundaries to guide our designation (see Criteria 
Used To Identify Critical Habitat section below). In regards to the 
areas adjacent to Unit SOL-1 along Highway 680, we believe we have 
properly designated the specific areas where those physical or 
biological features essential to the conservation of the species are 
found. Extending the unit to these adjacent

[[Page 12824]]

areas would require, as the commenter points out, the species to cross 
under the multilane highway through a culvert. Our review of the use of 
the area by the California red-legged frog shows the species in upland 
grassland habitats with no records into the Suisun Marsh area. Although 
the species may be able to access and use the Suisun Marsh area, we 
believe the species is more likely to use the upland grassland habitats 
and not the brackish marsh habitats associated with the Suisun Marsh. 
As a result of our examining the available habitat within the area and 
use of our mapping criteria, we believe we have used the best 
scientific information available on determining the critical habitat 
boundaries including those for Units SOL-1 and SOL-2.
    The final economic analysis prepared for this designation 
calculates potential impacts to agricultural crop farming activities. 
According to the final economic analysis, the relative incremental 
costs associated with the designation within Unit SOL-2 is less than 1 
percent of the total incremental costs of the designation and only 3 
percent of the total incremental costs associated with agricultural 
crop farming activities. Based on these results, we do not consider the 
estimated costs associated with the designation of critical habitat 
within Unit SOL-2 to be disproportionate and have not exercised our 
discretion to exclude any area within Unit SOL-2 under section 4(b)(2) 
of the Act. See ``Exclusions Under Section 4(b)(2) of the Act - 
Economic Exclusions'' section below for more information regarding 
exclusions.
    Comment (17): The San Francisco Public Utilities Commission 
(Commission) wrote in support of the two units proposed on portions of 
its property. Those units are SNM-1 and ALA-2 in San Mateo and Alameda 
Counties. The commenter added that the Commission has enacted 
additional protections for the frog, and that it is also preparing 
habitat conservation plans (HCPs) with the Service to protect 
endangered and threatened species and enhance their habitats within 
those areas.
    Response: We appreciate the support and look forward to working 
with the commenter in the future on continued conservation efforts for 
the California red-legged frog. We do not expect the HCPs to be 
completed by the time this designation is made effective (see the DATES 
section).
    Comment (18): Three commenters stated that they were not properly 
notified of the proposed rule, despite being landowners in designated 
areas or having submitted comments in the past.
    Response: We published the proposed critical habitat designation in 
the Federal Register on September 16, 2008 (73 FR 53491), and we 
accepted comments from all interested parties for 60 days, ending 
November 17, 2008. We then extended the public comment period for an 
additional 30 days (74 FR 19184; April 28, 2009). We later reopened the 
public comment period again for another 30 days (74 FR 51825; October 
8, 2009). For each publication, the Service wrote press releases that 
resulted in newspaper articles throughout California and specifically 
noticed the proposed designation in pertinent newspapers in the range 
of the California red-legged frog. We held a public meeting where we 
discussed opportunities for the public to comment and provide input and 
information. Thus, although we did not specifically notify individual 
landowners within the designation, we believe we provided adequate 
opportunity for individuals to review and provide comment on the 
proposed revised rule. It is our practice to include on our mailing 
lists those individuals who have made comments in the past regarding a 
specific issue. We apologize for having inadvertently failed to notify 
certain people of the proposed action and have updated our records 
accordingly.
    Comment (19): A commenter requested exclusion of approximately 
3,000 ac (1,214 ha) of private land proposed within unit MNT-3 because 
there is an existing conservation easement that protects habi