Endangered and Threatened Wildlife and Plants; Listing and Designation of Critical Habitat for the Chiricahua Leopard Frog, 14126-14207 [2011-4997]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 50 (Tuesday, March 15, 2011)]
[Proposed Rules]
[Pages 14126-14207]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-4997]



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Vol. 76

Tuesday,

No. 50

March 15, 2011

Part II





Department of the Interior





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Fish and Wildlife Service



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50 CFR Part 17



 Endangered and Threatened Wildlife and Plants; Listing and Designation 
of Critical Habitat for the Chiricahua Leopard Frog; Proposed Rule

Federal Register / Vol. 76 , No. 50 / Tuesday, March 15, 2011 / 
Proposed Rules

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2010-0085; MO 92210-0-0009-B4]
RIN 1018-AX12


Endangered and Threatened Wildlife and Plants; Listing and 
Designation of Critical Habitat for the Chiricahua Leopard Frog

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
designate critical habitat for the Chiricahua leopard frog (Lithobates 
chiricahuensis) under the Endangered Species Act of 1973, as amended. 
In total, we are proposing to designate approximately 11,136 acres 
(4,510 hectares) as critical habitat for the Chiricahua leopard frog. 
The proposed critical habitat is located in Apache, Cochise, Gila, 
Graham, Greenlee, Pima, Santa Cruz, and Yavapai Counties, Arizona; and 
Catron, Hidalgo, Grant, Sierra, and Socorro Counties, New Mexico. In 
addition, because of a taxonomic revision of the Chiricahua leopard 
frog, we are reassessing the status of and threats to the currently 
described species Lithobates chiricahuensis and proposing the listing 
as threatened of the currently described species.

DATES: We will consider comments received or postmarked on or before 
May 16, 2011. We must receive requests for public hearings, in writing, 
at the address shown in the FOR FURTHER INFORMATION CONTACT section by 
April 29, 2011.

ADDRESSES: You may submit comments by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments on Docket No. FWS-R2-
ES-2010-0085.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: Docket No. FWS-R2-ES-2010-0085; Division of Policy and Directives 
Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, 
Suite 222; Arlington, VA 22203.
    We will not accept e-mail or faxes. We will post all comments on 
the Internet at https://www.regulations.gov. This generally means that 
we will post any personal information you provide us (see the Public 
Comments section below for more information).

FOR FURTHER INFORMATION CONTACT: Steve Spangle, Field Supervisor, U.S. 
Fish and Wildlife Service, Arizona Ecological Services Field Office, 
2321 West Royal Palm Road, Suite 103, Phoenix, AZ 85021; telephone: 
602/242-0210; facsimile: 602/242-2513. If you use a telecommunications 
device for the deaf (TDD), call the Federal Information Relay Service 
(FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION: Due to a taxonomic revision of the 
Chiricahua leopard frog, we must reassess the status of and threats to 
the currently described Lithobates chiricahuensis. Therefore, this 
document consists of: (1) A proposed rule to list the Chiricahua 
leopard frog (Lithobates chiricahuensis) as threatened; and (2) a 
proposed rule to designate critical habitat for the Chiricahua leopard 
frog.

Previous Federal Actions

    We published a proposed rule to list the Chiricahua leopard frog as 
threatened in the Federal Register on June 14, 2000 (65 FR 37343). We 
published a final rule listing the species as threatened on June 13, 
2002 (67 FR 40790). Included in the final rule was a special rule (see 
50 CFR 17.43(b)) to exempt operation and maintenance of livestock tanks 
on non-Federal lands from the section 9 take prohibitions of the 
Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.). 
For further information on actions associated with listing the species, 
please see the final listing rule (67 FR 40790; June 13, 2002).
    In a May 6, 2009, order from the Arizona District Court, the 
Secretary of the Interior was required to publish a critical habitat 
prudency determination for the Chiricahua leopard frog and, if found 
prudent, a proposed rule to designate critical habitat by December 8, 
2010. Because of unforeseen delays related to species taxonomic issues, 
which required an inclusion of a threats analysis, we requested a 3-
month extension to the court-ordered deadlines for both the proposed 
and final rules. On November 24, 2010, the extension was granted and 
new deadlines of March 8, 2011, for the proposed rule and March 8, 
2012, for the final rule were established for completing and submitting 
the critical habitat rules to the Federal Register. This proposed rule 
is published in accordance with the Arizona District Court's ruling.

Public Comments

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other concerned governmental agencies, 
tribes, the scientific community, industry, or other interested parties 
concerning this proposed rule. We particularly seek comments 
concerning:
    (1) Information about the status of the species, especially the 
Ramsey Canyon portion of the range, including:
    (a) Genetics and taxonomy;
    (b) Historical and current range, including distribution patterns;
    (c) Historical and current population levels, and current and 
projected trends; and
    (d) Past and ongoing conservation measures for the species, its 
habitat, or both.
    (2) The factors that are the basis for making a listing 
determination for a species under section 4(a) of the Act, which are:
    (a) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (b) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (c) Disease or predation;
    (d) The inadequacy of existing regulatory mechanisms; or
    (e) Other natural or manmade factors affecting its continued 
existence.
    (3) Biological, commercial trade, or other relevant data concerning 
any threats (or lack thereof) to Chiricahua leopard frog and 
regulations that may be addressing those threats.
    (4) Additional information concerning the range, distribution, and 
population size of Chiricahua leopard frog, including the locations of 
any additional populations.
    (5) Any information on the biological or ecological requirements of 
Chiricahua leopard frog.
    (6) The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act, including whether 
there are threats to the species from human activities, how the 
designation may ameliorate or worsen those threats, and if any 
potential increase in threats outweighs the benefits of designation 
such that the designation of critical habitat may not be prudent.
    (7) Specific information on:
     The amount and distribution of the Chiricahua leopard 
frog's habitat;
     What areas occupied at the time of listing and that 
contain features essential to the conservation of the species should be 
included in the designation, and why;
     Special management considerations or protections that the 
physical and

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biological features essential to the conservation of the Chiricahua 
leopard frog that have been identified in this proposal may require, 
including managing for the potential effects of climate change; and
     What areas not occupied at the time of listing are 
essential for the conservation of the species, and why.
    (8) Land-use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat.
    (9) Any probable economic, national security, or other relevant 
impacts of designating as critical habitat any area that may be 
included in the final designation. We are particularly interested in 
any impacts on small entities or families, and the benefits of 
including or excluding areas that exhibit these impacts.
    (10) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate public concerns and 
comments.
    (11) Information on whether the benefits of an exclusion of any 
particular area outweigh the benefits of inclusion under section 
4(b)(2) of the Act.
    (12) Information on the projected and reasonably likely impacts of 
climate change on the Chiricahua leopard frog and the critical habitat 
areas we are proposing.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We will not 
accept comments sent by e-mail or fax or to an address not listed in 
the ADDRESSES section. We will not consider hand-delivered comments 
that we do not receive, or mailed comments that are not postmarked, by 
the date specified in the DATES section.
    We will post your entire comment--including any personal 
identifying information you provide--on https://www.regulations.gov. If 
you provide personal identifying information, such as your street 
address, phone number, or e-mail address, in your written comments, you 
may request at the top of your document that we withhold this 
information from public review. However, we cannot guarantee that we 
will be able to do so.
    A draft economic analysis and draft environmental assessment for 
this action will be prepared and made available to the public for 
review. At that time, we will reopen the comment period on this 
proposed rule and concurrently solicit comments on the draft economic 
analysis and draft environmental assessment.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on the Internet at https://www.regulations.gov, at Docket No. FWS-R2-ES-2010-0085, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Arizona Ecological Services Field Office, 2321 West 
Royal Palm Road, Suite 103, Phoenix, AZ 85021.

Proposed Threatened Status for the Chiricahua Leopard Frog

Background

    Due to a taxonomic revision of the Chiricahua leopard frog, we must 
reassess the status of and threats to the currently described species. 
It is our intent to discuss below only those topics directly relevant 
to the listing of the Chiricahua leopard frog as threatened in this 
section of the proposed rule. For more information on the Chiricahua 
leopard frog, refer to the final listing rule published in the Federal 
Register on June 13, 2002 (67 FR 40790) and the species' recovery plan 
(Service 2007).
Species Information
Description
    When we listed the Chiricahua leopard frog as a threatened species 
on June 13, 2002 (67 FR 40790), we recognized the scientific name as 
Rana chiricahuensis. Since that time, the genus name Lithobates was 
proposed by Frost et al. (2006, p. 249) and adopted by the Society for 
the Study of Amphibians and Reptiles in their most recent listing of 
scientific and standard English names of North American amphibians and 
reptiles north of Mexico (Crother 2008, p. 7). With the publication of 
this proposed rule, we officially accept the new scientific name of the 
Chiricahua leopard frog as Lithobates chiricahuensis.
    In addition, the Ramsey Canyon leopard frog (Lithobates 
subaquavocalis), found on the eastern slopes of the Huachuca Mountains, 
Cochise County, Arizona, has recently been subsumed into L. 
chiricahuensis (Crother 2008, p. 7) and was noted by the Service as 
part of the listed entity in a 90-day finding on 192 species from a 
petition to list 475 species (74 FR 66866; December 16, 2009). Goldberg 
et al. (2004, pp. 313-319) examined the relationships between the 
Ramsey Canyon leopard frog (L. subaquavocalis) and the Chiricahua 
leopard frog (L. chiricahuensis). Genetic analysis showed no evidence 
that Ramsey Canyon leopard frog was a separate species from the 
Chiricahua leopard frog (Goldberg et al. 2004, p. 315). The Society for 
the Study of Amphibians and Reptiles later adopted these leopard frogs 
as the same species, L. chiricahuensis (Crother 2008, p. 7). Therefore, 
we no longer recognize the Ramsey Canyon leopard frog (L. 
subaquavocalis) as a distinct species and consider it to be synonymous 
with the Chiricahua leopard frog (L. chiricahuensis). In this proposed 
rule, we present our analysis of the threats to the species given this 
taxonomic revision to determine if it is appropriate to list the 
Chiricahua leopard frog as threatened throughout its range (see Summary 
of Factors Affecting the Species below).
    Northern populations of the Chiricahua leopard frog in the Mogollon 
Rim region of east-central Arizona east to the eastern bajada of the 
Black Range in New Mexico are physically separated from populations to 
the south. Previous work had suggested these two separate divisions 
might be distinct species (Platz and Grudzien 1999, p. 51). Goldberg et 
al. (2004, p. 315) demonstrated that frogs from these two regions 
showed a 2.4 percent average divergence in mitochondrial DNA sequences. 
However, more recent work using both mitochondrial DNA and nuclear 
microsatellites from frog tissues throughout the range of the species 
provides no evidence of multiple taxa within what we now consider to be 
the Chiricahua leopard frog (Herrman et al. 2009, p. 18).
    The Chiricahua leopard frog is distinguished from other members of 
the leopard frog complex by a combination of characters, including a 
distinctive pattern on the rear of the thigh consisting of small, 
raised, cream-colored spots or tubercles (wart-like projections) on a 
dark background; folds on the back and sides that, towards the rear, 
are interrupted and deflected towards the middle of the body; stocky 
body proportions; relatively rough skin on the back and sides; eyes 
that are positioned relatively high on the head; and often green 
coloration on the head and back (Platz and Mecham 1979, p. 347.1; 
Degenhardt et al. 1996, pp. 85-87). The species also has a distinctive 
call consisting of a relatively long snore of 1 to 2 seconds in 
duration (Platz and Mecham 1979, p. 347.1; Davidson 1996, tracks 58, 
59). Overall body lengths of adults range from approximately 2.1 inches 
(in) (5.3 centimeters (cm)) to 5.4 in (13.7 cm) (Platz and Mecham 1979, 
p. 347.1; Stebbins 2003, pp. 236-237).

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Life History
    The life history of the Chiricahua leopard frog can be 
characterized as a complex life cycle, consisting of eggs and larvae 
that are entirely aquatic and adults who are primarily aquatic but may 
be terrestrial at times. Egg masses of Chiricahua leopard frogs have 
been reported in all months, but reports of egg laying (oviposition) in 
June and November through January are uncommon (Zweifel 1968, pp. 45-
46; Frost and Bagnara 1977, p. 449; Frost and Platz 1983, p. 67; Scott 
and Jennings 1985, p. 16; Sredl and Jennings 2005, p. 547). Frost and 
Platz (1983, p. 67) divided egg-laying activity into two distinct 
periods with respect to elevation. Populations at elevations below 
5,900 feet (ft) (1,798 meters (m)) tended to lay eggs from spring 
through late summer, with most activity taking place before June. 
Populations above 5,900 ft (1,798 m) bred in June, July, and August. 
Scott and Jennings (1985, p. 16) found a similar seasonal pattern of 
reproductive activity in New Mexico (February through September), as 
did Frost and Platz (1983, p. 67), although they did not note 
elevational differences. Additionally, Scott and Jennings (1985, p. 16) 
noted reduced egg laying in May and June. Zweifel (1968, p. 45) noted 
that breeding in the early part of the year appeared to be limited to 
sites where water temperatures do not get too low, such as spring-fed 
sites. Frogs at warm springs may lay eggs year-round (Scott and 
Jennings 1985, p. 16). Also, females attach spherical masses of 
fertilized eggs, ranging in number from 300 to 1,485 eggs, to submerged 
vegetation (Sredl and Jennings 2005, p. 547).
    Eggs hatch in approximately 8 to 14 days depending on temperature 
(Sredl and Jennings 2005, p. 547). After hatching, tadpoles remain in 
the water, where they feed and grow. Tadpoles turn into juvenile frogs 
in 3 to 9 months (Sredl and Jennings 2005, p. 547). Juvenile frogs are 
typically 1.4 to 1.6 in (35 to 40 millimeters (mm)) in overall body 
length. Males reach sexual maturity at 2.1 to 2.2 in (5.3 to 5.6 cm), a 
size they can attain in less than a year (Sredl and Jennings 2005, p. 
548).
    The diet of the Chiricahua leopard frog includes primarily 
invertebrates such as beetles, true bugs, and flies, but fish and 
snails are also taken (Christman and Cummer 2006, pp. 9-18). An adult 
was documented eating a hummingbird in southeastern Arizona (Field et 
al. 2003, p. 235). Chiricahua leopard frogs can be found active both 
day and night, but adults tend to be active more at night than 
juveniles (Sredl and Jennings 2005, p. 547). Chiricahua leopard frogs 
presumably experience very high mortality (greater than 90 percent) in 
the egg and early tadpole stages, high mortality when the tadpole turns 
into a juvenile frog, and then relatively low mortality when the frogs 
are adults (Zug et al. 2001, p. 303; Service 2007, pp. C10-C12). Under 
ideal conditions, Chiricahua leopard frogs may live as long as 10 years 
in the wild (Platz et al. 1997, p. 553).
Geographical Range and Distribution
    The range of the Chiricahua leopard frog includes central and 
southeastern Arizona; west-central and southwestern New Mexico; and in 
Mexico, northeastern Sonora, the Sierra Madre Occidental of 
northwestern and west-central Chihuahua, and possibly as far south as 
northern Durango (Platz and Mecham 1984, p. 347.1; Degenhardt et al. 
1996, p. 87; Sredl and Jennings 2005, p. 546; Brennan and Holycross 
2006, p. 44; Lemos-Espinal and Smith 2007, pp. 287, 579; Rorabaugh 
2008, p. 32). The distribution of the species in Mexico is unclear due 
to limited survey work and the presence of closely related taxa 
(especially Lithobates lemosespinali (no common name)) in the southern 
part of the range of the Chiricahua leopard frog. Based on 2009 data, 
the species still occurs in most major drainages in Arizona and New 
Mexico where it occurred historically; the exception to this is the 
Little Colorado River drainage in Arizona. The species is apparently 
extirpated from the Chiricahua Mountains of Arizona, which harbored the 
type locality. In Arizona and New Mexico, the species likely occurs at 
about 14 and 16 to 19 percent of its historical localities, 
respectively (Service 2007, p. 6).
Habitat
    Within its geographical range, breeding populations of this species 
historically inhabited a variety of aquatic habitats (Service 2007, p. 
3); however, the species is now limited primarily to headwater streams 
and springs, and livestock tanks into which nonnative predators (e.g., 
sportfishes, American bullfrogs (Lithobates catesbeianus), crayfish 
(Orconectes virilis), barred tiger salamanders (Ambystoma mavortium 
mavortium)) have not yet invaded or been introduced, or where the 
numbers of nonnative predators are low and habitats are complex, 
allowing Chiricahua leopard frogs to coexist with these species 
(Service 2007, p. 15). The large valley-bottom cienegas (mid-elevation 
wetland communities typically surrounded by relatively arid 
environments), rivers, and lakes where the species occurred 
historically are populated with nonnative predators at densities with 
which the Chiricahua leopard frog cannot coexist.
Dispersal
    Although one of the most aquatic of southwestern leopard frogs 
(Degenhardt et al. 1996, p. 86), Chiricahua leopard frogs are known to 
move among aquatic sites, and such movements are crucial for conserving 
metapopulations. A metapopulation is a set of local populations that 
interact via individuals moving between local populations (Hanski and 
Gilpin 1991, p. 7). If local populations are extirpated through 
drought, disease, or other factors, the populations can be recolonized 
via dispersal from adjacent populations. Hence, the long-term viability 
of metapopulations may be enhanced over that of isolated populations, 
even though local populations experience periodic extirpations. To 
determine whether metapopulation structure exists in a specific group 
of local populations, the dispersal capabilities of the frog must be 
understood. Based on a review of available information, the recovery 
plan (Service 2007, pp. D-2, D-3, K-3) provides a rule of thumb on 
dispersal capabilities. Chiricahua leopard frogs are reasonably likely 
to disperse 1.0 mile (mi) (1.6 kilometers (km)) overland, 3.0 mi (4.8 
km) along ephemeral or intermittent drainages (water existing only 
briefly), and 5.0 mi (8.0 km) along perennial water courses (water 
present at all times of the year), or some combination thereof not to 
exceed 5.0 mi (8.0 km). This is often referred to as the ``1-3-5 rule'' 
of dispersal.

Summary of Factors Affecting the Species

    Section 4 of the Act and its implementing regulations (50 CFR part 
424) set forth the procedures for adding species to the Federal Lists 
of Endangered and Threatened Wildlife and Plants (Lists). A species may 
be determined to be endangered or threatened due to one or more of the 
five factors described in section 4(a)(1) of the Act: (A) The present 
or threatened destruction, modification, or curtailment of its habitat 
or range; (B) overutilization for commercial, recreational, scientific, 
or educational purposes; (C) disease or predation; (D) the inadequacy 
of existing regulatory mechanisms; and (E) other natural or manmade 
factors affecting its continued existence. The final listing rule for 
the Chiricahua leopard frog (67 FR 40790; June 13, 2002) contained a 
discussion of these five factors, as did the proposed

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rule (65 FR 37343; June 14, 2000). Threats discussed in the previous 
listing rules are still affecting the Chiricahua leopard frog today. 
Please refer to these rules or the Chiricahua leopard frog recovery 
plan (Service 2007; pp. 18-45) for a more detailed analysis of the 
threats affecting the species. Because we no longer recognize the 
Ramsey Canyon leopard frog as a distinct species and consider it to be 
synonymous with the Chiricahua leopard frog, we reanalyzed factors 
relevant to the entire listed entity below. However, because all the 
threats from the previous rules still apply, we provide a summary of 
those below.

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

    The recovery plan lists the following threats to habitat or range 
of the Chiricahua leopard frog: Mining, including mining-related 
contaminants; other contaminants; dams; diversions; stream 
channelization; groundwater pumping; woodcutting; urban and 
agricultural development; road construction; grazing by livestock and 
elk; climate change; and altered fire regimes (Service 2007, pp. 31-
37). Although these threats are widespread and varied, a threats 
assessment that was accomplished as part of the recovery plan showed 
chytridiomycosis and predation by nonnative species as consistently 
more important threats than these habitat-based factors (Service 2007, 
pp. 20-27).
    Chiricahua leopard frogs are fairly tolerant of variations in water 
quality, but likely do not persist in waters severely polluted with 
cattle feces (Service 2007, p. 34), or runoff from mine tailings or 
leach ponds (Rathbun 1969, pp. 1-3; U.S. Bureau of Land Management 
1998, p. 26; Service 2007, p. 36). Furthermore, variation in pH, 
ultraviolet radiation, and temperature, as well as predation stress, 
can alter the potency of chemical effects (Akins and Wofford 1999, p. 
107; Monson et al. 1999, pp. 309-311; Reylea 2004, pp. 1081-1084). 
Chemicals may also serve as a stressor that makes frogs more 
susceptible to disease, such as chytridiomycosis (see discussion under 
Factor C below) (Parris and Baud 2004, p. 344). The effects of 
pesticides and other chemicals on amphibians can be complex because of 
indirect effects on the amphibian environment, direct lethal and 
sublethal effects on individuals, and interactions between contaminants 
and other factors associated with amphibian decline (Sparling 2003, pp. 
1101-1120; Reylea 2008, pp. 367-374).
    A copper mine (the Rosemont Mine) has been proposed in the 
northeastern portion of the Santa Rita Mountains, Pima County, Arizona 
(recovery unit 2), the footprint of which includes several sites 
recently occupied by Chiricahua leopard frogs. Recent research 
indicates that Chiricahua leopard frog tadpoles are sensitive to 
cadmium and copper above certain levels (Little and Calfee 2008, pp. 6-
10), making the introduction of copper into Chiricahua leopard frog 
habitat a possible significant threat. No analyses have been conducted 
yet to quantify how the frogs and their habitats may be affected in 
that region, which potentially includes the Bureau of Land Management's 
Las Cienegas National Riparian Conservation Area; however, a draft 
environmental impact statement will likely be published in 2011.
    The Southwest Endangered Species Act Team (2008, pp. iii-IV-5) 
published ``Chiricahua leopard frog (Lithobates [Rana] chiricahuensis) 
considerations for making effects determinations and recommendations 
for reducing and avoiding adverse effects,'' which included detailed 
descriptions of how many different types of projects, including fire 
management, construction, native fish recovery, and livestock 
management projects, may affect the frog and its habitat. This 
document, in addition to the recovery plan (Service 2007, pp. 31-37), 
can be referenced for more information about habitat-related threats 
to. Habitat-related threats to the Chiricahua leopard frog, while not 
the most important factors threatening the species, nevertheless affect 
the Chiricahua leopard frog such that the species is likely to become 
endangered within the foreseeable future.

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

    Even though the final listing rule (67 FR 40790; June 13, 2002) 
discussed over-collection for the pet trade as a possible threat, we 
have no information that leads us to believe that overutilization for 
commercial, recreational, scientific, or educational purposes is 
currently a threat to the Chiricahua leopard frog.

C. Disease and Predation

    The threats assessment conducted during the preparation of the 
recovery plan (Service 2007, pp. 18-45) found that disease 
(chytridiomycosis) and predation by nonnative species (bullfrogs, 
crayfish, fish, and tiger salamanders) are the most important threats 
to the Chiricahua leopard frog.
Disease
    In some areas, Chiricahua leopard frog populations are known to be 
seriously affected by chytridiomycosis. Chytridiomycosis is an 
introduced fungal skin disease caused by the organism Batrachochytrium 
dendrobatidis or ``Bd.'' Voyles et al. (2009) hypothesized that Bd 
disrupts normal regulatory functioning of frog skin, and evidence 
suggests that electrolyte depletion and osmotic imbalance that occur in 
amphibians with severe chytridiomycosis are sufficient to cause 
mortality. This disease has been associated with numerous population 
extirpations, particularly in New Mexico, and with major die-offs in 
other populations of Chiricahua leopard frogs (Service 2007).
Predation
    Prior to the invasion of perennial waters by predatory, nonnative 
species (American bullfrog, crayfish, fish species), the frog was 
historically found in a variety of aquatic habitat types. Today, 
leopard frogs in the southwestern United States are so strongly 
impacted by harmful nonnative species, which are most prevalent in 
perennial waters, that the leopard frogs' occupied niche is 
increasingly restricted to the uncommon environments that do not 
contain these nonnative predators, and these environments now tend to 
be ephemeral and unpredictable. Witte et al. (2008, p. 378) found that 
sites with disappearances of Chiricahua leopard frogs were 2.6 times 
more likely to have introduced crayfish than were control sites. 
Unfortunately, few sites with bullfrogs were included in the Witte et 
al. (2008, pp. 375-383) study, and at many sites, there was no 
identification of the species of fish present.
Summary of Factor C
    Overall, the Chiricahua leopard frog has made modest population 
gains in Arizona in spite of disease and predation, but is apparently 
declining in New Mexico because of these threats. We consider disease, 
specifically chytridiomycosis, and predation by nonnative species to be 
threats affecting the species such that the species is likely to become 
endangered within the foreseeable future.

D. Inadequacy of Existing Regulatory Mechanisms

    The Chiricahua leopard frog is currently listed as a threatened 
species (67 FR 40790; June 13, 2002) with a special rule (see 50 CFR 
17.43(b)) to exempt operation and maintenance of livestock tanks on 
non-Federal lands from the section 9 take prohibitions of

[[Page 14130]]

the Act. Even with regulatory protections of the Act currently in 
place, nonnative species used for fishing baits in Chiricahua leopard 
frog habitats pose a significant threat to the Chiricahua leopard frog; 
use of these nonnative species as fishing baits presents a vehicle for 
the distribution of these often predatory or competitive bait species 
into frog habitat and for the dissemination of deadly diseases to the 
frog. Picco and Collins (2008, pp. 1585-1587) found waterdogs (tiger 
salamanders; Ambystoma tigrinum) infected with chytridiomycosis in 
Arizona bait shops, and waterdogs infected with ranavirus in Arizona, 
New Mexico, and Colorado bait shops. Furthermore, they found that 26 to 
67 percent of anglers released tiger salamanders bought as bait into 
the waters where they fish, and 4 percent of bait shops released tiger 
salamanders back into the wild after they were housed in shops with 
infected animals, despite the fact that release of live salamanders is 
prohibited by Arizona Game and Fish Commission Orders. This study 
showed the inadequacy of current State regulations in regard to 
preventing the spread of amphibian diseases via the waterdog bait 
trade. Even though the Chiricahua leopard frog is currently listed 
under the Endangered Species Act as a threatened species, additional 
regulation or increased enforcement of existing regulations or both are 
needed to stem the spread of amphibian diseases via use of waterdogs 
for bait. Therefore, we consider the inadequacy of current regulatory 
mechanisms to prevent the spread of amphibian diseases via the bait 
trade to be a threat such that the species is likely to become 
endangered within the foreseeable future.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

Small Populations
    Among the potential threats in this category discussed in the 
Chiricahua leopard frog recovery plan (Service 2007, pp. i-M-17) and 
the final listing rule (67 FR 40790; June 13, 2002), are genetic and 
stochastic effects that manifest in small populations. Specifically, 
small populations are vulnerable to extirpation due to random 
variations in age structure and sex ratios, as well as from disease or 
other natural events that a larger population is more likely to 
survive. Inbreeding depression and loss of genetic diversity in small 
populations can also reduce the fitness of individuals and the ability 
of a population to adapt to change. The recent genetic study revealed 
no systemic lack of genetic diversity within the Chiricahua leopard 
frog as a species (Herrmann et al. 2009, pp. 12-17). In fact, 
populations were quite variable; up to 16 different genetic groupings 
were found. This does not preclude the possibility that individual 
populations may suffer from genetic or demographic problems, but the 
study shows the species retains good genetic variability.
Climate Change
    The Chiricahua leopard frog recovery plan (Service 2007, pp. 40-43) 
describes anticipated effects of climate change on the Chiricahua 
leopard frog. The plan cited literature indicating that temperatures 
rose in the 20th century and warming is predicted to continue over the 
21st century (Service 2007, pp. 40-43). Climate models are less certain 
about predicted trends in precipitation, but the southwestern United 
States is expected to become drier. Since the recovery plan was 
prepared, the Intergovernmental Panel on Climate Change (IPCC) (2007, 
pp. 1-8) published a report stating that global warming is occurring 
and that precipitation patterns are being affected.
    According to the IPCC report, global mean precipitation is 
anticipated to increase, but not uniformly (IPCC 2007, p. 8). In the 
American Southwest and elsewhere in the middle latitudes, precipitation 
is expected to decrease. There is also high confidence that many semi-
arid areas like the western United States will suffer a decrease in 
water resources due to climate change, as a result of less annual mean 
precipitation and reduced length of snow season and snow depth (IPCC 
2007, p. 8). Although most climate models predict a drying trend in the 
21st century in the southwestern United States, these predictions are 
less certain than predicted warming trends. The models do not predict 
summer precipitation well, and typically at least half of precipitation 
within the range of the Chiricahua leopard frog occurs in the summer 
months (Brown 1982, pp. 58-62; Guido 2008, p. 5). Furthermore, there 
have been no trends either in summer rainfall over the last 100 years 
in Arizona (Guido 2008, pp. 3-5), or since 1955 in annual precipitation 
in the western United States (van Mantgem et al. 2009, p. 523). On the 
other hand, all severe, multi-year droughts in the southwestern United 
States and northwestern Mexico have been associated with La Ni[ntilde]a 
events (Seager et al. 2007, p. 3), during which sea surface 
temperatures in the tropical Pacific decline. Climate models predict 
that drought driven by La Ni[ntilde]a events will be deeper and more 
profound than any during the last several hundred years (Seager et al. 
2007, p. 3).
    Drought has likely contributed to loss of Chiricahua leopard frog 
populations since the species was originally listed in 2002. Stock tank 
populations are particularly vulnerable to loss, because they tend to 
dry out during periods of below normal precipitation. These trends are 
likely to continue, but the situation is complicated by interactions 
with other factors. For example, the effects of drought cannot be 
separated from the effects of introduced aquatic predators, because 
drought will affect those predators as well as populations of 
Chiricahua leopard frogs. The interaction between predators and drought 
resistance of frog habitats is often a delicate balance. Stock tanks 
are likely an important habitat for Chiricahua leopard frogs in part 
because these sites dry out periodically, which rids them of most 
aquatic predators. Leopard frogs can often withstand drying of stock 
tanks for 30 days or more, whereas fish and bullfrogs may not. However, 
if stock tanks dry for longer periods of time, neither leopard frogs 
nor introduced predators may be capable of persisting. Drought will 
reduce habitats of both leopard frogs and introduced predators, but 
exactly how that will affect the Chiricahua leopard frog will probably 
be site-specific. At this time, it is difficult to predict how drought 
will impact the overall species' status, but Chiricahua leopard frog 
sites could be buffered from the effects of drought by wells or other 
anthropogenic water supplies. Even though drought may contribute to 
loss of site-specific populations, we do not consider it to be a threat 
to the species at this time or in the foreseeable future.
    Additionally, the effects of chytridiomycosis on frogs are related 
to water temperature. Sites where Chiricahua leopard frogs coexist with 
the disease are typically at lower elevations and are warmer sites 
(Service 2007, p. 26). As a result, if temperatures increase as 
predicted, perhaps more populations will be able to persist with the 
disease. Thus climate change, particularly in the form of increased 
water temperatures, does not seem to pose a significant threat to the 
Chiricahua leopard frog into the foreseeable future.
Summary of Factor E
    The Chiricahua leopard frog recovery plan (Service 2007) describes 
genetic and stochastic effects that manifest in small populations and 
the anticipated effects of climate change on the Chiricahua leopard 
frog as potential threats to the species. Herrmann et al.'s

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recent genetic study (2009, pp. 12-17), however, revealed no systemic 
lack of genetic diversity within Chiricahua leopard frog populations. 
Moreover, climate change, particularly in the form of increased water 
temperatures, does not seem to pose a significant threat to the 
Chiricahua leopard frog into the foreseeable future. As such, other 
natural or manmade factors affecting the species' continued existence 
do not appear to be a threat affecting the Chiricahua leopard frog such 
that the species is likely to become endangered within the foreseeable 
future.

Proposed Determination

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the Chiricahua leopard frog. In summary, the most significant 
threats to the Chiricahua leopard frog include the effects of the 
disease chytridiomycosis, which has been associated with major die-offs 
in some populations of Chiricahua leopard frogs (Service 2007, pp. B8-
B88), and predation by nonnative species (Factor C). Additional factors 
affecting the species include degradation and loss of habitat as a 
result of water diversions and groundwater pumping, poor livestock 
management, altered fire regimes due to fire suppression and livestock 
grazing, mining, contaminants, development, and other human activities; 
and inadequate regulatory mechanisms regarding introduction of 
nonnative bait species (Factors A and D) (67 FR 40800-40806, June 13, 
2002; Sredl and Jennings 2005, pp. 546-549; Service 2007, pp. B1-B88).
    Evidence indicates that, since the time of listing, the species has 
probably made modest population gains in Arizona, but is apparently 
declining in New Mexico. Overall in the United States, the status of 
the Chiricahua leopard frog is either static or improving. The status 
and trends for the species are unknown in Mexico. An aggressive 
recovery program is underway in the United States, and reestablishment 
of populations, creation of refugial populations, and habitat 
enhancement and creation have helped stabilize or improve the status of 
the species in some areas. Although progress has been made to secure 
some existing populations and establish new populations, the status of 
the species continues to be affected by threats such that the species 
is likely to become endangered within the foreseeable future throughout 
all or a significant portion of its range. Due primarily to ongoing 
conservation measures and the existence of relatively robust 
populations and metapopulations, we have determined that the species is 
not in immediate danger of extinction (i.e., on the brink of 
extinction). However, because we believe that the present threats are 
likely to continue in the future (such as chytrid fungus and nonnative 
predators spreading and increasing in prevalence and range, affecting 
more populations of the leopard frog, thus increasing the threats in 
the foreseeable future), we have determined that the Chiricahua leopard 
frog is likely to become in danger of extinction throughout all or a 
significant portion of its range in the foreseeable future. Therefore, 
we determine that the Chiricahua leopard frog meets the definition of a 
threatened species under the Act.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened under the Act include recognition, recovery actions, 
requirements for Federal protection, and prohibitions against certain 
practices. Recognition through listing results in public awareness and 
conservation by Federal, State, and local agencies; private 
organizations; and individuals. The Act provides for possible 
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 certain activities involving 
listed wildlife are discussed in Effects of Critical Habitat 
Designation and are further discussed, in part, below.
    Section 7(a) of the Act 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) 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 agency actions within the species' habitat that may require 
conference or consultation or both as described in the preceding 
paragraph include management and any other landscape-altering 
activities on Federal lands administered by the Department of Defense, 
U.S. Fish and Wildlife Service, U.S. Forest Service, and Bureau of Land 
Management; issuance of section 404 Clean Water Act (33 U.S.C. 1251 et 
seq.) permits by the U.S. Army Corps of Engineers; and construction and 
maintenance of roads or highways by the Federal Highway Administration.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to all endangered 
wildlife. The prohibitions, codified at 50 CFR 17.21 for endangered 
wildlife and 50 CFR 17.31 for threatened wildlife, in part, make it 
illegal for any person subject to the jurisdiction of the United States 
to take (includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect; or to attempt any of these), import, export, ship 
in interstate commerce in the course of commercial activity, or sell or 
offer for sale in interstate or foreign commerce any listed species. It 
is also 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.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered or threatened wildlife species under certain 
circumstances. Regulations governing permits are codified at 50 CFR 
17.22 for endangered species and 50 CFR 17.32 for threatened wildlife. 
You may obtain permits for scientific purposes, to enhance the 
propagation or survival of the species, and for incidental take in 
connection with otherwise lawful activities.
    It is our policy, as 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 a proposed 
listing on proposed and ongoing activities within the range of species 
proposed for listing. The following activities could potentially result 
in a violation of section 9 of the Act; this list is not comprehensive:
    (1) Unauthorized collecting, handling, possessing, selling, 
delivering, carrying, or transporting of the species, including import 
or export across State lines and

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international boundaries, except for properly documented antique 
specimens of these taxa at least 100 years old, as defined by section 
10(h)(1) of the Act.
    (2) Introduction of nonnative species that compete with or prey 
upon the Chiricahua leopard frog, such as the introduction of 
competing, nonnative crayfish to the States of Arizona or New Mexico.
    (3) The unauthorized release of biological control agents that 
attack any life stage of this species.
    (4) Unauthorized modification of the channel or water flow of any 
stream or water body in which the Chiricahua leopard frog is known to 
occur.
    Questions regarding whether specific activities would constitute a 
violation of section 9 of the Act should be directed to the Arizona 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT). 
Requests for copies of the regulations concerning listed animals and 
general inquiries regarding prohibitions and permits may be addressed 
to the U.S. Fish and Wildlife Service, Endangered Species Permits, P.O. 
Box 1306, Albuquerque, NM 87103; telephone: 505-248-6633; facsimile: 
505-248-6788.

Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (i) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features (PBFs):
    (I) Essential to the conservation of the species and
    (II) Which may require special management considerations or 
protection; and
    (ii) specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided under the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, and law 
enforcement; habitat acquisition, enhancement, protection, and 
maintenance; propagation and population reestablishment or 
augmentation; and, in the extraordinary case where population pressures 
within a given ecosystem cannot be otherwise relieved, may include 
regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against Federal agencies carrying out, funding, 
or authorizing activities likely to result in the destruction or 
adverse modification of critical habitat. Section 7(a)(2) requires 
consultation on Federal actions that may affect critical habitat. The 
designation of critical habitat does not affect land ownership or 
establish a refuge, wilderness, reserve, preserve, or other 
conservation area. Such designation does not allow the government or 
public to access private or other non-Federal lands. Such designation 
does not require implementation of restoration, recovery, or 
enhancement measures by non-Federal landowners. Where a landowner seeks 
or requests Federal agency funding or authorization for an action that 
may affect a listed species or critical habitat, the consultation 
requirements of section 7(a)(2) would apply, but even in the event of a 
destruction or adverse modification finding, the Federal action 
agency's and the applicant's obligation is not to restore or recover 
the species, but to avoid destruction or adverse modification of 
critical habitat.
    For inclusion in a critical habitat designation, the habitat within 
the geographical area occupied by the species at the time it was listed 
must contain the PBFs essential to the conservation of the species, and 
be included only if those features may require special management 
considerations or protection. Critical habitat designations identify, 
to the extent known using the best scientific and commercial data 
available, habitat areas that provide essential life cycle needs of the 
species (areas on which are found the PBFs laid out in the appropriate 
quantity and spatial arrangement for the conservation of the species). 
Under the Act and regulations at 50 CFR 424.12, we can designate 
critical habitat in areas outside the geographical area occupied by the 
species at the time it was listed only when we determine that those 
areas are essential for the conservation of the species and that 
designation limited to those areas occupied at the time of listing 
would be inadequate to ensure the conservation of the species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658)), and our associated Information Quality 
Guidelines, provide criteria, establish procedures, and provide 
guidance to ensure that our decisions are based on the best scientific 
data available. They require our biologists, to the extent consistent 
with the Act and with the use of the best scientific data available, to 
use primary and original sources of information as the basis for 
recommendations to designate critical habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources may include the recovery plan for the 
species; articles in peer-reviewed journals; conservation plans 
developed by Federal agencies, States, or local governments; scientific 
status surveys and studies; biological assessments; or other 
unpublished materials and expert opinion or personal knowledge.
    Habitat is often dynamic, and species may move from one area to 
another over time. This is particularly true of the Chiricahua leopard 
frog. Furthermore, we recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be 
required for recovery of the species.
    Areas that are important to the conservation of the species, but 
are outside the critical habitat designation, will continue to be 
subject to conservation actions we implement under section 7(a)(1) of 
the Act. Areas that support populations are also subject to the 
regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available scientific 
information at the time of the agency action. Federally funded or 
permitted projects affecting listed species outside their designated 
critical habitat areas may still result in jeopardy findings in some 
cases. Similarly, critical habitat designations made on the basis of 
the best available information at the time of designation will not 
control the direction and substance of future recovery plans, habitat 
conservation plans (HCPs), or

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other species conservation planning efforts if new information 
available at the time of these planning efforts calls for a different 
outcome.

Prudency Determination

    Section 4 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 the 
species is determined to be endangered or threatened. Our regulations 
at 50 CFR 424.12(a)(1) state that the 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 activity and the 
identification of critical habitat can be expected to increase the 
degree of threat to the species; or (2) the designation of critical 
habitat would not be beneficial to the species.
    There is no documentation that the Chiricahua leopard frog is 
significantly threatened by collection. Although human visitation to 
Chiricahua leopard frog habitat carries with it the possibility of 
introducing infectious disease and potentially increasing other threats 
where the frogs occur, the locations of important recovery areas are 
already accessible to the public through Web sites, reports, online 
databases, and other easily accessible venues. Therefore, identifying 
and mapping critical habitat is unlikely to increase threats to the 
species or its habitat. In the absence of finding that the designation 
of critical habitat would increase threats to a species, if there are 
any benefits to a critical habitat designation, then a prudent finding 
is warranted. The potential benefits of critical habitat to the 
Chiricahua leopard frog include: (1) Triggering consultation under 
section 7 of the Act, in new areas for actions in which there may be a 
Federal nexus where it would not otherwise occur because, for example, 
it is or has become unoccupied or the occupancy is in question; (2) 
focusing conservation activities on the most essential features and 
areas; (3) providing educational benefits to State or county 
governments or private entities; and (4) preventing people from causing 
inadvertent harm to the species. Therefore, because we have determined 
that the designation of critical habitat will not likely increase the 
degree of threat to the species and may provide some measure of 
benefit, we find that designation of critical habitat is prudent for 
the Chiricahua leopard frog.

Proposed Critical Habitat Designation for Chiricahua Leopard Frog

Background

    It is our intent to discuss only those topics directly relevant to 
the designation of critical habitat for the Chiricahua leopard frog in 
this section of the proposed rule.
Physical and Biological Features
    In accordance with section 3(5)(A)(i) and 4(b)(1)(A) of the Act and 
the regulations at 50 CFR 424.12, in determining which areas to propose 
as critical habitat within the geographical area occupied at the time 
of listing, we consider the physical and biological features (PBFs) 
essential to the conservation of the species that may require special 
management considerations or protection. These include, but are not 
limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historical, geographical, and ecological 
distributions of a species.
    We derived the specific PBFs required for the Chiricahua leopard 
frog from the studies of this species' habitat, ecology, and life 
history as described below. These needs are identified in the species' 
recovery plan (Service 2007), particularly in the Habitat 
Characteristics and Ecosystems section of Part 1: Background (pp. 15-
18); in the Recovery Strategy in Part 11: Recovery (pp. 49-51); in 
Appendix C--Population and Habitat Viability Analysis (pp. C8-C35); and 
in Appendix D--Guidelines for Establishing and Augmenting Chiricahua 
Leopard Frog Populations, and for Refugia and Holding Facilities (pp. 
D2-D5). Additional insight is provided by Degenhardt et al. (1996, pp. 
85-87), Sredl and Jennings (2005, pp. 546-549), and Witte et al. (2008, 
pp. 5-8).
Space for Individual and Population Growth and for Normal Behavior
    Generally, Chiricahua leopard frogs need aquatic breeding and 
overwintering sites, both in the context of metapopulations and as 
isolated populations. For this species, a metapopulation should consist 
of at least four local populations that exhibit regular recruitment, 
three of which are continually in existence. Local populations should 
be arranged in geographical space in such a way that no local 
population will be greater than 5.0 mi (8.0 km) from at least one other 
local population during some part of the year unless facilitated 
dispersal is planned (Service 2007, p. K-3). Movement of frogs among 
local populations is reasonably certain to occur if those populations 
are separated by no more than 1.0 mi (1.6 km) overland, 3.0 mi (4.8 km) 
along ephemeral or intermittent drainages, 5.0 mi (8.0 km) along 
perennial water courses, or some combination thereof not to exceed 5.0 
mi (8.0 km) (the ``1-3-5 rule'' of dispersal, see ``Dispersal'' in the 
Background section above). Metapopulations should include at least one 
large, healthy subpopulation (e.g., at least 100 adults) in order to 
achieve an acceptable level of viability as a larger unit. If aquatic 
habitats can be managed for persistence through drought periods (e.g., 
supplying water via a pipeline or a well, lining a pond), overall 
metapopulation viability may be achievable with a smaller number of 
individuals per subpopulation (e.g., 40 to 50 adults) (Service 2007, p. 
K-3).
    Isolated breeding populations are also essential for the 
conservation of the frog because they buffer against disease and 
disease organisms that can spread rapidly through a metapopulation as 
infected individuals move among aquatic sites. An isolated, but robust, 
breeding population should be beyond the reasonable dispersal distance 
(see ``Dispersal'' in the Background section) from other Chiricahua 
leopard frog populations, contain at least 60 adults, and exhibit a 
diverse age class distribution that is relatively stable over time. A 
population of 40 to 50 adults can also be robust or strong if it 
resides in a drought-resistant habitat (Service 2007, p. K-5). At least 
two metapopulations and one isolated robust population are needed in 
each recovery unit to meet the recovery criteria in the recovery plan 
(Service 2007, p. 53).
Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements
    Chiricahua leopard frogs are fairly tolerant of variations in water 
quality, but likely do not persist in waters severely polluted with 
cattle feces (Service 2007, p. 34) or runoff from mine tailings or 
leach ponds (Rathbun 1969, pp. 1-3; U.S. Bureau of Land Management 
1998, p. 26; Service 2007, p. 36). Furthermore, variation in pH, 
ultraviolet radiation, and temperature, as well as predation stress, 
can alter the

[[Page 14134]]

potency of chemical effects (Akins and Wofford 1999, p. 107; Monson et 
al. 1999, pp. 309-311; Reylea 2004a, pp. 1081-1084). Chemicals may also 
serve as a stressor that makes frogs more susceptible to disease, such 
as chytridiomycosis (Parris and Baud 2004, p. 344). The effects of 
pesticides and other chemicals on amphibians can be complex because of 
indirect effects on the amphibian environment, direct lethal and 
sublethal effects on individuals, and interactions between contaminants 
and other factors associated with amphibian decline (Sparling 2003, pp. 
1101-1120; Reylea 2008, pp. 367-374).
Cover or Shelter
    Chiricahua leopard frogs are most often encountered in or very near 
water, generally at breeding locations. Only rarely are they found very 
far from water. That said, they can be found basking or foraging in 
riparian vegetation and on open banklines out to the edge of riparian 
vegetation. These upland areas provide essential foraging and basking 
sites. A combination of open ground and vegetation cover is desirable 
for basking and foraging, respectively. Vegetation in these areas 
provide habitat for prey species and protection from terrestrial 
predators (those living on dry land). In particular, Chiricahua leopard 
frogs use these upland areas during the summer rainy season.
Sites for Breeding, Reproduction, or Rearing (or Development) of 
Offspring
    Aquatic breeding habitat is essential for providing space, food, 
and cover necessary to sustain all life stages of Chiricahua leopard 
frogs. Suitable breeding habitat consists of permanent or nearly 
permanent aquatic habitats from about 3,200 to 8,900 ft (975 to 2,715 
m) elevation with deep (greater than 20 in (0.5 m)) pools in which 
nonnative predators are absent or occur at such low densities and in 
complex habitats to allow persistence of Chiricahua leopard frogs 
(Service 2007, pp. 15-18, D-3). Included are cienegas or springs, 
pools, livestock tanks, lakes, reservoirs, streams, and rivers. Sites 
as small as 6.0-ft (1.8-m) diameter steel troughs can serve as 
important breeding sites, particularly if that population is part of a 
metapopulation that can be recolonized from adjacent sites if 
extirpation occurs. Some of the most robust extant breeding populations 
are in earthen livestock watering tanks. Absence of the disease 
chytridiomycosis is crucial for population persistence in some regions, 
particularly in west-central New Mexico and at some other locales, as 
well. However, some populations persist with the disease (e.g., sites 
between Interstate 19 and the Baboquivari Mountains, Arizona) with few 
noticeable effects on demographics or survivorship. Persistence with 
disease is enhanced in warm springs and at lower elevations with warmer 
water (Service 2007, pp. 22-27, B67).
    To be considered essential breeding habitat, water must be 
permanent enough to support breeding, tadpole development to 
metamorphosis (change into a frog), and survival of frogs. Tadpole 
development lasts 3 to 9 months, and some tadpoles overwinter (Sredl 
and Jennings 2005, p. 547). Juvenile and adult frogs need moisture for 
survival, including sites for hibernation. Overwintering sites of 
Chiricahua leopard frogs have not been investigated; however, 
hibernacula (shelter occupied during winter by inactive animals) of 
related species include sites at the bottom of well-oxygenated ponds, 
burial in mud, or moist caves (Service 2007, p. 17). Given these 
requirements, sites that dry out for 1 month or more will not provide 
essential breeding or overwintering habitat. However, occasional drying 
for short periods (less than 1 month) may be beneficial in that the 
frogs can survive, but nonnative predators, particularly fish, and in 
some cases, American bullfrogs and populations of aquatic forms of 
tiger salamanders, will be eliminated during the dry period (Service 
2007, p. D3). Water quality requirements at breeding sites included 
having a pH equal to or greater than 5.6 (Watkins-Colwell and Watkins-
Colwell 1998, p. 64), salinities less than 5 parts per thousand (Ruibal 
1959, pp. 318-319), and very little chemical pollutants, including but 
not limited to heavy metals, pesticides, mine runoff, and fire 
retardants, where the pollutants do not exceed the tolerance of 
Chiricahua leopard frogs (Rathbun 1969, pp. 1-3; U.S. Bureau of Land 
Management 1998, p. 26; Boone and Bridges 2003, pp. 152-167; Calfee and 
Little 2003, pp. 1527-1531; Sparling 2003, pp. 1109-1111; Relyea 2004b, 
pp. 1741-1746; Service 2007, p. 36; Little and Calfee 2008, pp. 6-10). 
White (2004, pp. 53-54, 73-79, 136-140) provides specific pesticide use 
guidelines for minimizing impacts to the Chiricahua leopard frog.
    Essential aquatic breeding sites require some open water. 
Chiricahua leopard frogs can be eliminated from sites that become 
entirely overgrown with cattails (Typha sp.) or other emergent plants. 
At the