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

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.

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: http://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

http://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

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

http://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

http://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 subaquavocali

s), 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).

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

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

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 Niña 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 Niña 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

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

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

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

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 same time, frogs need some emergent or submerged vegetation, root masses, undercut banks, fractured rock substrates, or some combination thereof as refugia from predators and extreme climatic conditions (Sredl and Jennings 2005, p. 547). In essential breeding habitat, if nonnative crayfish, predatory fishes, bullfrogs, or barred tiger salamanders are present, they occur only as rare dispersing individuals that do not breed, or are at low enough densities in habitats that are complex and with abundant escape cover (

e.g.,

aquatic and emergent vegetation cover, diversity of moving and stationary water) that persistence of both Chiricahua leopard frogs and nonnative species can occur (Sredl and Howland 1995, pp. 383-384; Service 2007, pp. 20-22, D3; Witte

et al.

2008, pp. 7-8).

Habitats that are protected from disturbance or are representative of the historical, geographical, and ecological distributions of a species.

In some areas, Chiricahua leopard frog populations are known to be seriously affected by the fungal skin disease chytridiomycosis. This disease has been associated with numerous population extirpations, particularly in recovery unit 6 in New Mexico (Service 2007, pp. 5-6, 24-27). The frog appears to be less susceptible to mortality from the disease in warmer waters and at lower elevations. The precise temperature at which frogs can coexist with the disease is unknown and may depend on a variety of factors; however, at Cuchillo Negro Warm Springs, Sierra County, New Mexico, Chiricahua and plains leopard frogs (

Lithobates blairi

) become uncommon to nonexistent where winter water temperatures drop below about 20 degrees Celsius (°C) (68 degrees Fahrenheit (°F)) (Christman 2006a, p. 8). A pH of greater than 8 during at least part of the year may also limit the ability of the disease to be an effective pathogen (Service 2007, pp. 26-27). Furthermore, based on experience in Arizona, particularly the Huachuca Mountains, if Chiricahua leopard frogs are absent for a period of months or years, the disease organism may drop out of the system or become scarce enough that frogs can persist again if reestablished. Essential breeding habitats either lack chytridiomycosis or include conditions that allow for persistence of Chiricahua leopard frogs with the disease, as in warmer waters or at lower elevations.

Dispersal Habitat

Dispersal habitat provides routes for connectivity and gene flow among local populations within a metapopulation, which enhances the likelihood of metapopulation persistence and allows for recolonization of sites that are lost due to drought, disease, or other factors

(Hanski and Gilpin 1991, pp. 4-6; Service 2007, p. 50). Detailed studies of dispersal and metapopulation dynamics of Chiricahua leopard frogs have not been conducted; however, Jennings and Scott (1991, pp. 1-43) noted that maintenance of corridors used by dispersing juveniles and adults that connect separate populations may be critical to conserving populations of frogs. As a group, leopard frogs are surprisingly good at dispersal. In Michigan, young northern leopard frogs (

Lithobates pipiens

) commonly move up to 0.5 mi (0.8 km) from their birthplace, and three young males established residency up to 3.2 mi (5.2 km) away from where they were born (Dole 1971, p. 221). Movement may occur via dispersal of frogs or passive transport of tadpoles along stream courses. The maximum distance moved by a radio-telemetered Chiricahua leopard frog in New Mexico was 2.2 mi (3.5 km) in one direction along a drainage (Service 2007, p. 18). In 1974, Frost and Bagnara (1977, p. 449) noted passive or active movement of Chiricahua and plains leopard frogs for 5 mi (8 km) or more along East Turkey Creek in the Chiricahua Mountains, Arizona. In August 1996, Rosen and Schwalbe (1998, p. 188) found up to 25 young adult and subadult Chiricahua leopard frogs at a roadside puddle in the San Bernardino Valley, Arizona. They believed that the only possible origin of these frogs was a stock tank located 3.5 mi (5.5 km) away. In September 2009, 15 to 20 Chiricahua leopard frogs were found at Peña Blanca Lake west of Nogales. The nearest likely source population was Summit Reservoir, a straight line distance of 3.1 mi (4.9 km) overland or approximately 4.4 mi (7.0 km) along intermittent drainages (Service 2010b, pp. 7-8).

Movements away from water do not appear to be random. Streams are important dispersal corridors for young northern leopard frogs (Seburn

et al.

1997, pp. 68-70). Displaced northern leopard frogs will return to their place of origin, and may use olfactory, visual, or auditory cues, and possibly celestial orientation, as guides (Dole 1968, pp. 395-398; 1972, pp. 275-276; Sinsch 1991, pp. 542-544). Based on this and other information (Service 2007, pp. 12-14) and as noted in the Background section above, Chiricahua leopard frogs are reasonably likely to disperse 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 (continuous) water courses, or some combination thereof not to exceed 5.0 mi (8.0 km). Dispersal habitat must provide corridors through which leopard frogs can move among aquatic breeding sites in metapopulations. These dispersal habitats will often be drainages connecting aquatic breeding sites, and may include ephemeral, intermittent, and perennial waters that are not suitable for breeding. The most likely dispersal routes may include combinations of ephemeral, intermittent, and perennial drainages, as well as uplands. Some vegetation cover for protection from predators, and aquatic sites that can serve as buffers against desiccation (drying) and stop-overs for foraging (feeding) are desirable along dispersal routes. A lack of barriers that would block dispersal is critical. Features on the landscape likely to serve as partial or complete barriers to dispersal, include cliff faces and urban areas (Service 2007, p. D-3), reservoirs 20 acres (ac) (50 hectares (ha)) or more in size that are stocked with sportfishes or other nonnative predators, highways, major dams, walls, or other structures that physically block movement (Andrews

et al.

2008, pp. 124-132; Eigenbrod

et al.

2009, pp. 32-40; 75 FR 12818, March 17, 2010). The effects of highways on frog dispersal can be mitigated with frog fencing and culverts (Service 2007, pp. I7-I8). Unlike some other species of leopard frogs, Chiricahua leopard frogs have only rarely been found in association with agricultural fields; hence, agriculture may also serve as a barrier to movement.

Primary Constituent Elements for the Chiricahua Leopard Frog

Under the Act and its implementing regulations, we are required to identify the physical and biological features essential to the conservation of the Chiricahua leopard frog in areas occupied at the time of listing, focusing on the features' primary constituent elements (PCEs). We consider primary constituent elements to be the elements of physical and biological features that, when laid out in the appropriate quantity and spatial arrangement to provide for a species' life-history processes, are essential to the conservation of the species.

Based on the above needs and our current knowledge of the life history, biology, and ecology of the species, and the habitat requirements for sustaining the essential life-history functions of the species, we have determined that the PCEs essential to the conservation of the Chiricahua leopard frog are:

(1) Aquatic breeding habitat and immediately adjacent uplands exhibiting the following characteristics:

(a) Perennial (water present during all seasons of the year) or nearly perennial pools or ponds at least 6.0 ft (1.8 m) in diameter and 20 in (0.5 m) in depth;

(b) Wet in most years, and do not or only very rarely dry for more than a month;

(c) pH greater than or equal to 5.6;

(d) Salinity less than 5 parts per thousand;

(e) Pollutants absent or minimally present at low enough levels that they are barely detectable;

(f) Emergent and or submerged vegetation, root masses, undercut banks, fractured rock substrates, or some combination thereof; but emergent vegetation does not completely cover the surface of water bodies;

(g) Nonnative crayfish, predatory fishes, bullfrogs, barred tiger salamanders, and other introduced predators absent or occurring at levels that do not preclude presence of the Chiricahua leopard frog;

(h) Absence of chytridiomycosis, or if chytridiomycosis is present, then conditions that allow persistence of Chiricahua leopard frogs with the disease (

e.g.,

water temperatures that do not drop below 20 °C (68 °F), pH of greater than 8 during at least part of the year); and

(i) Uplands immediately adjacent to breeding sites that Chiricahua leopard frogs use for foraging and basking.

(2) Dispersal habitat, consisting of ephemeral (water present for only a short time), intermittent, or perennial drainages that are generally not suitable for breeding, and associated uplands that provide overland movement corridors for frogs among breeding sites in a metapopulation with the following characteristics:

(a) Are not 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 drainages, or some combination thereof not to exceed 5.0 mi (8.0 km);

(b) Provide some vegetation cover for protection from predators, and in drainages, some ephemeral, intermittent, or perennial aquatic sites; and

(c) Are free of barriers that block movement by Chiricahua leopard frogs, including urban, industrial, or agricultural development; reservoirs that are 50 ac (20 ha) or more in size and stocked with predatory fishes, bullfrogs, or crayfish; highways that do not include frog fencing and culverts; and walls, major dams, or other structures that physically block movement.

With this proposed designation of critical habitat, we intend to conserve the PCEs essential to the conservation of the species through the identification of the appropriate quantity and spatial

arrangement of the PCEs sufficient to support the life-history functions of the species. Because not all life-history functions require both PCEs 1 and 2, not all areas proposed as critical habitat will contain both PCEs. Each of the areas proposed in this rule has been determined to contain sufficient PCEs, or, with reasonable effort, PCEs can be restored, to provide for one or more of the life-history functions of the Chiricahua leopard frog.

Under our regulations, we are required to identify the PCEs within the geographical area occupied by the Chiricahua leopard frog at the time of listing that are essential to the conservation of the species and which may require special management considerations or protections. The PCEs are laid out in a specific spatial arrangement and quantity determined to be essential to the conservation of the species. All proposed critical habitat units are within the species' historical geographical range in the United States and contain sufficient PCEs to support at least one life-history function. In addition, all but two proposed critical habitat units, units 13 and 17, are currently occupied by Chiricahua leopard frogs. Units 13 and 17 were occupied at the time of listing and currently contain sufficient PCEs to support life-history functions essential for the conservation of the species. These units are needed as future sites for frog colonization or reestablishment and could be restored (

e.g.,

control of nonnative predators) to allow Chiricahua leopard frog persistence with a reasonable level of effort.

Special Management Considerations or Protection

When designating critical habitat, we assess whether the specific areas within the geographical area occupied by the species at the time of listing contain features that are essential to the conservation of the species and that may require special management considerations or protection.

All areas proposed for designation as critical habitat will require some level of management to address the current and future threats to the Chiricahua leopard frog and to maintain or restore the PCEs. Special management in aquatic breeding sites will be needed to ensure that these sites provide water quantity, quality, and permanence or near permanence; cover; and absence of extraordinary predation and disease that can affect population persistence. In dispersal habitat, special management will be needed to ensure frogs can move through those sites with reasonable success. The designation of critical habitat does not imply that lands outside of critical habitat do not play an important role in the conservation of the Chiricahua leopard frog. Federal activities that may affect areas outside of critical habitat, such as construction of water diversions, permitting livestock grazing, sportfish stocking, channelization, levee construction, energy development, fire and fuels management, and road construction, are still subject to review under section 7 of the Act if they may affect the Chiricahua leopard frog because Federal agencies must consider both effects to the frog and effects to critical habitat independently. The prohibitions of section 9 of the Act also continue to apply both inside and outside of designated critical habitat.

A detailed discussion of activities influencing the Chiricahua leopard frog and its habitat can be found in the final listing rule (67 FR 40790; June 13, 2002) and the recovery plan (Service 2007, pp. 18-45). The recovery plan also contains recovery-unit-specific threat assessments (Service 2007, pp. B1-B88). Activities that may warrant special management of the physical and biological features that define essential habitat (appropriate quantity and distribution of PCEs) for the Chiricahua leopard frog include, but are not limited to, introduction of predators, such as bullfrogs, crayfish, sportfishes, and barred tiger salamanders; introduction or spread of chytridiomycosis; recreational activities; livestock grazing; water diversions and development; construction and maintenance of roads and utility corridors; fire suppression, fuels management, and prescribed fire; and various types of development. These activities have the potential to affect critical habitat and PCEs if they are conducted within designated units or upstream and in some cases downstream in the floodplains of those units; however, some of these activities, when conducted appropriately, may be compatible with maintenance of adequate PCEs.

Criteria Used To Identify Critical Habitat

As required by section 4(b) of the Act, we used the best scientific and commercial data available in determining areas within the geographical area occupied at the time of listing that contain the features essential to the conservation of the Chiricahua leopard frog, and areas outside of the geographical area occupied at the time of listing that are essential for the conservation of the species. Areas occupied at the time of listing are identified and described in Rorabaugh (2010, pp. 7-17) and information cited therein for Arizona, and for New Mexico in Jennings (1995, pp. 10-21), Painter (2000, pp. 10-21), and 67 FR 40793 (June 13, 2002). We have also reviewed available information that pertains to the habitat requirements of this species. The following were particularly useful: Degenhardt

et al.

(1996, pp. 85-87), Sredl and Jennings (2005, pp. 546-549), Service (2007, pp. 15-18, 47-48), and Witte

et al.

(2008, pp. 5-8).

Units occupied at the time of listing include the specific sites occupied by Chiricahua leopard frogs in June 2002 that contain sufficient PCEs to support life-history functions essential for the conservation of the species. Included are sites where the species was breeding as well as localities where dispersing individuals were present, and other sites for which the breeding status was unknown. If metapopulation structure was known or suspected, dispersal habitats connecting breeding populations within metapopulations are also proposed.

Sites not known to be occupied at the time of listing in June 2002 are also proposed as critical habitat if they are essential to the conservation of the species. Specifically, we assessed whether they are needed to meet the following recovery criterion from the recovery plan: At least two metapopulations located in different drainages (defined here as USGS 10-digit Hydrologic Units) plus at least one isolated and robust population occur in each recovery unit and exhibit long-term persistence and stability (even though local populations may go extinct in metapopulations, Service 2007, p. 53). If sites are needed to meet that criterion, they are proposed for critical habitat herein. At the time of listing, 3 of the units being proposed for critical habitat were unoccupied, and for 10 additional units, their occupancy status was unknown (

see

Table 1). However, all 13 of these units are currently occupied and possess one or both PCEs, or have the ability to develop the PCEs with a reasonable level of restoration work. These units, which were unoccupied or not known to be occupied at the time of listing, are being proposed as critical habitat because they currently contain known breeding populations of Chiricahua leopard frogs, which are relatively scarce (33 populations in Arizona and 20 to 23 in New Mexico), are all considered essential to the conservation of the species, and help meet the population goals in the recovery criterion discussed above.

Table 1—Occupancy of Chiricahua Leopard Frog by Proposed Critical Habitat Units

Critical habitat unit

Occupied at time of listing?

Currently occupied?

Recovery Unit 1 (Tumacacori-Atascosa-Pajarito Mountains, Arizona and Mexico)

(1) Twin Tanks and Ox Frame Tank

Unknown

Yes.

(2) Garcia Tank

Yes

Yes.

(3) Buenos Aires NWR Central Tanks

Yes

Yes.

(4) Bonita, Upper Turner, and Mojonera Tanks

Yes

Yes.

(5) Sycamore Canyon

Yes

Yes.

(6) Peña Blanca Lake and Spring and Associated Tanks

Yes

Yes.

Recovery Unit 2 (Santa Rita-Huachuca-Ajos Bavispe, Arizona and Mexico)

(7) Florida Canyon

Unknown

Yes.

(8) Eastern Slope of the Santa Rita Mountains

Unknown

Yes.

(9) Las Cienegas National Conservation Area

Yes

Yes.

(10) Pasture 9 Tank

No

Yes.

(11) Scotia Canyon

No

Yes.

(12) Beatty's Guest Ranch

Yes

Yes.

(13) Carr Barn Pond

Yes

No.

(14) Ramsey and Brown Canyons

No

Yes.

Recovery Unit 3 (Chiricahua Mountains-Malpai Borderlands-Sierra Madre, Arizona, New Mexico, and Mexico)

(15) High Lonesome Well

Yes

Yes.

(16) Peloncillo Mountains

Yes

Yes.

(17) Cave Creek

Yes

No.

(18) Leslie Creek

Yes

Yes.

(19) Rosewood and North Tanks

Yes

Yes.

Recovery Unit 4 (Piñaleno-Galiuro-Dragoon Mountains, Arizona)

(20) Deer Creek

Yes

Yes.

(21) Oak Spring and Oak Creek

Unknown

Yes.

(22) Dragoon Mountains

Yes

Yes.

Recovery Unit 5 (Mogollon Rim-Verde River, Arizona)

(23) Buckskin Hills

Yes

Yes.

(24) Crouch, Gentry, and Cherry Creeks, and Parallel Canyon

Yes

Yes.

(25) Ellison and Lewis Creeks

Unknown

Yes.

Recovery Unit 6 (White Mountains-Upper Gila, Arizona and New Mexico)

(26) Concho Bill and Deer Creek

Unknown

Yes.

(27) Campbell Blue and Coleman Creeks

Yes

Yes.

(28) Tularosa River

Yes

Yes.

(29) Deep Creek Divide Area

Yes

Yes.

(30) Main Diamond Creek

Yes

Yes.

(31) Beaver Creek

Unknown

Yes.

Recovery Unit 7 (Upper Gila-Blue River, Arizona and New Mexico)

(32) Left Prong of Dix Creek

Unknown

Yes.

(33) Rattlesnake Pasture Tank and Associated Tanks

Unknown

Yes.

(34) Coal Creek

Unknown

Yes.

(35) Blue Creek

Yes

Yes.

Recovery Unit 8 (Black-Mimbres-Rio Grande, New Mexico)

(36) Seco Creek

Yes

Yes.

(37) Alamosa Warm Springs

Yes

Yes.

(38) Cuchillo Negro Warm Springs and Creek

Yes

Yes

(39) Ash and Bolton Springs

Yes

Yes

(40) Mimbres River

Yes

Yes.

Recovery planning is focused on these existing breeding populations and building on them with habitat rehabilitation and population reestablishments to construct metapopulations and isolated robust populations needed to meet the recovery criterion. Such work is underway in all recovery units, but is further along in some than others. In particular, recovery units 1 (Tumacacori-Atascosa-Pajarito Mountains, Arizona and Sonora), 2 (Santa Rita-Huachuca-Ajos Bavispe, Arizona and Sonora), 3 (Chiricahua Mountains-Malpai Borderlands-Sierra Madre), 4 (Pinaleño-Galiuro-Dragoon Mountains, Arizona), 5 (Mogollon

Rim—Verde River, Arizona), and 8 (Black-Mimbres-Rio Grande, New Mexico) are moving towards meeting the above-cited recovery criterion, and metapopulations and isolated, robust populations have been or are being identified (Rorabaugh 2010, pp. 17-30; Service 2010a, pp. 2-7; 2010b, pp. 2-9). In these recovery units, unoccupied sites have sometimes been identified by the Service, in cooperation with the recovery team steering committees and local recovery groups, where population reestablishment is needed to complete a metapopulation or to establish an isolated, robust population (Rorabaugh 2010, pp. 17-30; Service 2010a, pp. 2-7; 2010b, pp. 2-9). These unoccupied sites are proposed as critical habitat herein.

Identification of such recovery sites in recovery units 6 (White Mountains-Upper Gila, Arizona and New Mexico) and 7 (Upper Gila-Blue River, Arizona and New Mexico) is more difficult, because less work or progress in recovery has been made in these areas. The recovery plan identifies management areas, which are areas within recovery units with the greatest potential for successful recovery actions and threat alleviation (Service 2007, p. 49). Within recovery units 6 and 7, critical habitat has been proposed at specific sites within management areas with the greatest potential for building metapopulations and isolated robust populations. As in other recovery units, existing breeding populations were used either as subpopulations in metapopulations or as isolated, robust populations. Metapopulations were constructed with these existing breeding populations, sites occupied at the time of listing that still retain PCEs sufficient to support life-history functions essential for the conservation of the species, and unoccupied sites with one or more PCEs or the potential to support PCEs with a reasonable level of restoration work. In metapopulations, all of these sites are within reasonable dispersal distance (the “1-3-5 rule” described above) of each other. In recovery unit 7, enough sites could not be found that meet the definition of critical habitat to construct two metapopulations and one isolated, robust population. Similarly, in recovery unit 6, one metapopulation exists, plus several isolated populations, but we have not been able to find aquatic sites that meet the definition of critical habitat to build a second metapopulation. In particular, other aquatic sites, some of which were occupied at the time of listing, lack the PCEs sufficient to support life-history functions essential for the conservation of the species, primarily due to presence of chytridiomycosis, which is a very serious threat in recovery unit 6. This recovery unit will require further investigation, and habitat restoration or creation may be needed to provide additional habitat for breeding Chiricahua leopard frog populations that can contribute to meeting the population goals in the recovery criterion discussed above.

Also included in this critical habitat proposal are dispersal corridors among subpopulations within a metapopulation. These corridors were selected as the most likely routes for dispersal of frogs among sites, based on reasonable dispersal distances along perennial and ephemeral or intermittent drainages, or via overland routes where PCE 2 is present. Our selection of routes assumes perennial drainages are better dispersal corridors than ephemeral or intermittent drainages, and the ephemeral or intermittent drainages are better dispersal corridors than overland routes. We also assume that, if all else is equal, the shorter the route the more likely Chiricahua leopard frogs will successfully disperse along it. In addition, we considered the presence of waterfalls, steep slopes, and other obstacles that may be difficult for a frog to negotiate.

When determining proposed critical habitat boundaries within this proposed rule, we made every effort to avoid including developed areas such as lands covered by buildings, pavement, and other structures because such lands lack PCEs for the Chiricahua leopard frog. The scale of the maps we prepared under the parameters for publication within the Code of Federal Regulations may not reflect the exclusion of such developed lands. Any such lands inadvertently left inside critical habitat boundaries shown on the maps of this proposed rule have been excluded by text in the proposed rule and are not proposed for designation as critical habitat. Therefore, if the critical habitat is finalized as proposed, a Federal action involving these lands would not trigger section 7 consultation with respect to critical habitat and adverse modification would not be prohibited under 7(a)(2) unless the specific action would affect the PCEs in the adjacent critical habitat.

We are proposing for designation of critical habitat lands that we have determined are occupied at the time of listing and contain sufficient PCEs to support life-history functions essential for the conservation of the species and lands outside of the geographical area occupied at the time of listing that we have determined are essential for the conservation of the species.

Critical habitat units are proposed for designation based on sufficient PCEs being present to support the Chiricahua leopard frog's life processes. Some units contain both PCEs 1 and 2 and support multiple life processes. Some units contain one of the PCEs or only the potential to develop PCEs necessary to support the Chiricahua leopard frog's particular use of that habitat. In most cases, aquatic sites within metapopulations contain both PCEs 1 and 2. Isolated aquatic sites contain only PCE 1, and dispersal corridors only contain PCE 2, or a reasonable potential to develop those PCEs.

Proposed Critical Habitat Designation

We are proposing 40 units as critical habitat for the Chiricahua leopard frog. The critical habitat areas we describe below constitute our current best assessment of areas that meet the definition of critical habitat for the species. All 40 units we are proposing as critical habitat are within the species' geographical range, including areas occupied at the time of listing and areas not known to be occupied at the time of listing but identified as essential for the conservation of the species (Platz and Mecham 1984, p. 347.1). Table 1 below shows the specific occupancy status of each unit at the time of listing and currently (based on the most recent data available) (Rorabaugh 2010, pp. 7-30; Service files). The approximate area of each proposed critical habitat unit is shown in Table 2. The 40 areas we propose as critical habitat are grouped herein by recovery unit.

Table 2—Proposed Critical Habitat Units for the Chiricahua Leopard Frog

[Area estimates reflect all land within critical habitat unit boundaries. Note that grazing allotments are not considered in private ownership.]

Critical habitat unit

Land ownership by type

acres (hectares)

Federal

State

Private

Size of unit in acres

(hectares)

(1) Twin Tanks and Ox Frame Tank

0

1.3 (0.5)

0.4 (0.2)

1.7 (0.7)

(2) Garcia Tank

0.7 (0.3)

0

0

0.7 (0.3)

(3) Buenos Aires NWR Central Tanks

1,720 (696)

0

0

1,720 (696)

(4) Bonita, Upper Turner, and Mojonera Tanks

201 (81)

0

0

201 (81)

(5) Sycamore Canyon

262 (106)

0

7 (3)

268 (108)

(6) Peña Blanca Lake and Spring and Associated Tanks

202 (82)

0

0

202 (82)

(7) Florida Canyon

4 (2)

0

0

4 (2)

(8) Eastern Slope of the Santa Rita Mountains

172 (70)

0

14 (6)

186 (75)

(9) Las Cienegas National Conservation Area

1,235 (500)

186 (75)

0

1,420 (575)

(10) Pasture 9 Tank

0

0

0.5 (0.2)

0.5 (0.2)

(11) Scotia Canyon

70 (29)

0

0

70 (29)

(12) Beatty's Guest Ranch

0

0

10 (4)

10 (4)

(13) Carr Barn Pond

0.6 (0.3)

0

0

0.6 (0.3)

(14) Ramsey and Brown Canyons

58 (24)

0

65 (26)

123 (50)

(15) High Lonesome Well

0

0

0.4 (0.2)

0.4 (0.2)

(16) Peloncillo Mountains

366 (148)

0

289 (117)

655 (265)

(17) Cave Creek

234 (95)

0

92 (37)

326 (132)

(18) Leslie Creek

26 (11)

0

0

26 (11)

(19) Rosewood and North Tanks

0

78 (31)

19 (8)

97 (39)

(20) Deer Creek

17 (7)

69 (28)

34 (14)

120 (48)

(21) Oak Spring and Oak Creek

27 (11)

0

0

27 (11)

(22) Dragoon Mountains

74 (30)

0

0

74 (30)

(23) Buckskin Hills

232 (94)

0

0

232 (94)

(24) Crouch, Gentry, and Cherry Creeks, and Parallel Canyon

334 (135)

64 (26)

6 (3)

404 (163)

(25) Ellison and Lewis Creeks

83 (34)

0

15 (6)

99 (40)

(26) Concho Bill and Deer Creek

17 (7)

0

0

17 (7)

(27) Campbell Blue and Coleman Creeks

174 (70)

0

0

174 (70)

(28) Tularosa River

335 (135)

0

1,575 (637)

1,910 (772)

(29) Deep Creek Divide Area

408 (165)

0

102 (41)

510 (206)

(30) Main Diamond Creek

14 (6)

0

40 (16)

54 (22)

(31) Beaver Creek

132 (54)

0

25 (10)

157 (64)

(32) Left Prong of Dix Creek

13 (5)

0

0

13 (5)

(33) Rattlesnake Pasture Tank and Associated Tanks

59 (24)

0

0

59 (24)

(34) Coal Creek

7 (3)

0

0

7 (3)

(35) Blue Creek

24 (10)

0

12 (5)

37 (15)

(36) Seco Creek

66 (27)

0

610 (247)

676 (273)

(37) Alamosa Warm Springs

0.2 (0.1)

25 (10)

54 (22)

79 (32)

(38) Cuchillo Negro Warm Springs and Creek

3 (1)

3 (1)

23 (9)

28 (12)

(39) Ash and Bolton Springs

0

0

49 (20)

49 (20)

(40) Mimbres River

0

0

1,097 (444)

1,097 (444)

Total

6,571 (2,661)

426 (173)

4,139 (1,676)

11,136

(4,510)

Note: Area sizes may not sum due to rounding.

We present brief descriptions of all units, and reasons why they meet the definition of critical habitat for the Chiricahua leopard frog, below. Unless indicated otherwise below, the physical and biological features of critical habitat in stream and riverine lotic (actively moving water) systems are contained within the riverine and riparian ecosystems formed by the wetted channel and adjacent floodplains within 328 lateral ft (100 lateral m) on either side of bankfull stage. Bankfull stage is generally considered to be that level of stream discharge reached just before flows spill out onto the adjacent floodplain. The discharges that occur at bankfull stage, in combination with the range of flows that occur over a length of time, govern the shape and size of the river channel (Rosgen 1996, pp. 2-2 to 2-4; Leopold 1997, pp. 62-63, 66). The use of bankfull stage and 328 ft (100 m) on either side recognizes the naturally dynamic nature of riverine systems, recognizes that floodplains are an integral part of the stream ecosystem, and contains the features essential to the conservation of the species.

Ephemeral drainages (containing water for only brief periods) proposed as critical habitat for dispersal corridors among breeding sites in metapopulations will, in some cases, be less distinct than the stream or river reaches where frogs breed. Nonetheless, these ephemeral drainages will still be defined by wetland plant species, denser or taller specimens of upland species, channel characteristics such as sandy or gravelly soils that contrast with upland soils, the presence of cut banks, or some combination of these. Where dispersal corridors cross uplands, proposed critical habitat is 328 ft (100 m) wide, the centerline of which is the line delineated on our critical habitat maps and legal descriptions.

In ponds proposed as critical habitat, most of which are impoundments for watering cattle or other livestock, proposed critical habitat extends for 20 ft (6.1 m) beyond the high water line or to the boundary of the riparian and upland vegetation edge, whichever is greatest. The frogs are commonly found foraging and basking within 20 feet of

the shoreline of tanks. In addition, proposed critical habitat extends upstream from ponds from the extent of the boundary for 328 ft (100 m) from the high water line. The proposed critical habitat extends to 328 ft (100 m) upstream because there is often a riparian drainage coming into the tank, and the frogs are likely moving along those drainages. Also, the high water line is defined as that water level which, if exceeded, results in overflow of the pond. In most cases, this is the elevation of the spillway in livestock impoundments.

Recovery Unit 1 (Tumacacori-Atascosa-Pajarito Mountains, Arizona and Mexico)

Unit 1: Twin Tanks and Ox Frame Tank

Unit 1 consists of 1.3 ac (0.5 ha) of lands owned by the Arizona State Land Department and 0.4 ac (0.2 ha) of private lands in the Sierrita Mountains, Pima County, Arizona. Twin Tanks is on lands owned and managed by the Arizona State Land Department and consists of two tanks in proximity to each other as well as a drainage running between them. Ox Frame Tank is on private lands. This unit is proposed as critical habitat because it is essential for the conservation of the species.

Occupancy of these livestock tanks at the time of listing is unknown, as they were not surveyed for frogs until 2007; however, these sites are important breeding sites for recovery. Twin Tanks held more than 1,000 frogs in 2008, and is a robust breeding population. Ox Frame and Twin tanks are too far apart (4.3 mi (7.0 km) overland) across rugged terrain to expect frogs to move between these sites. Hence, these tanks serve as isolated populations. PCE 1 is present at both sites. The Twin Tanks area is less than 0.5 mi (0.8 km) upslope of active mining at Freeport McMoRan's Sierrita Copper Mine and could be affected by those mining activities. Both sites are also at risk of introduction of nonnative predators, such as bullfrogs and crayfish. Presence of chytridiomycosis at these tanks has not been investigated.

Unit 2: Garcia Tank

Unit 2, consisting of 0.7 ac (0.3 ha), is a former cattle tank located on the Buenos Aires National Wildlife Refuge (NWR), Pima County, Arizona. It is a double tank; the southwest or downstream impoundment is what dependably holds water, but both parts of the tank are proposed as critical habitat. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCE 1) to support life-history functions essential for the conservation of the species.

A breeding site, this unit was known to have been occupied in 2002 and 2006. Leopard frogs were noted in 2010, but they were not identified to species (the lowland leopard frog,

Lithobates yavapaiensis,

is known to occur in the area). It is about 3.6 mi (5.8 km) over land across dissected and hilly terrain to the next nearest population at Lower Carpenter Tank. The nearest known populations to the east are on the Coronado National Forest more than 9.0 mi (14 km) away. Hence, this site is isolated and is managed as an isolated, robust population. The greatest threats needing management are introductions of or colonization by nonnative species, such as bullfrogs and crayfish; and drought that could greatly reduce or eliminate the aquatic habitat.

Unit 3: Buenos Aires NWR Central Tanks

This unit, consisting of 1,720 ac (696 ha) within the Buenos Aires National Wildlife Refuge (NWR), Pima County, Arizona, includes former cattle tanks and other waters used as breeding and dispersal sites plus intervening and connecting drainages and uplands. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Core breeding sites at permanent or nearly permanent tanks (Carpenter, Rock, State, Triangle, and New Round Hill) support the strongest metapopulation known within the range of the species. Chongo Tank, where a population was established in 2009, may become a sixth breeding site. Seven other tanks support frogs periodically to regularly, and breeding and recruitment likely takes place at these tanks in wet cycles. Frogs occupied Carpenter, Rock, and Triangle Tanks in 2002 at or about the time of listing. Tanks proposed for designation include Carpenter, Rock, State, Triangle, New Round Hill, Banado, Choffo, Barrel Cactus, Sufrido, Hito, Morley, McKay, and Chongo Tanks. McKay Tank is actually a cluster of three tanks, all of which are proposed as critical habitat. Also proposed as critical habitat are the intervening drainages, including: (1) Puertocito Wash from Triangle Tank north through and including Aguire Lake to New Round Hill Tank, then upstream to the confluence with Las Moras Wash, and upstream in Las Moras Wash to Chongo Tank; (2) an unnamed drainage from Puertocito Wash upstream to McKay Tank; (3) an unnamed drainage from Puertocito Wash upstream to Rock Tank, including Morley Tank, then upstream in an unnamed drainage to the top of that drainage, directly overland to an unnamed drainage, and then upstream to Hito Tank and downstream to McKay Tank; (4) from Sufrido Tank downstream in an unnamed drainage to its confluence with an unnamed drainage running between Rock and Morley tanks; (5) Lopez Wash from Carpenter Tank downstream to Aguire Lake; (6) an unnamed drainage from its confluence with Lopez Wash upstream to Choffo Tank; (7) an unnamed drainage from its confluence with Lopez Wash upstream to State Tank; (8) an unnamed drainage from Banado Tank downstream to its confluence with an unnamed drainage, then upstream in that drainage to Barrel Cactus Tank; and (9) an unnamed drainage from Banado Tank upstream to a saddle, then directly downslope to Lopez Wash.

In this unit, bullfrogs remain a threat, but efforts are underway to eliminate the last known populations of bullfrogs in the Altar Valley (on the Santa Margarita Ranch to the south of Buenos Aires NWR). Frogs in this area have tested positive for chytridiomycosis, but the disease appears to have little effect on population viability.

Unit 4: Bonita, Upper Turner, and Mojonera Tanks

This unit includes 201 ac (81 ha) of Coronado National Forest lands in the Pajarito and Atascosa Mountains, Santa Cruz County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs to support life-history functions essential for the conservation of the species.

Two breeding sites (Bonita Tank and Mojonera Tank), combined with a dispersal site or site where breeding and recruitment may occur in wet years (Upper Turner Tank), form the nucleus for a future metapopulation. Three additional waters—Sierra Tank East, Sierra Tank West, and Sierra Well—may have the potential to support breeding with habitat work. Frogs currently occupy Bonita and Mojonera Tanks, and Bonita was occupied at the time of listing. Frogs were last found at Upper Turner Tank in 2004. The occupancy status of Mojonera and Upper Turner Tanks at the time of listing is unknown. The proposed critical habitat in Unit 4 also includes intervening drainages, uplands, and ephemeral or intermittent waters as follows: (1) From Upper Turner Tank upstream in an unnamed drainage to its confluence with a minor drainage coming in from the east, then directly upslope in that drainage and

east to a saddle, and directly downslope to Bonita Canyon, and upstream in Bonita Canyon to Bonita Tank; and (2) from Mojonera Tank downstream in Mojonera Canyon to a sharp bend where the drainage turns west-northwest, then southeast and upstream in an unnamed drainage to a saddle, downslope through an unnamed drainage to its confluence with another unnamed drainage, upstream in that unnamed drainage to a saddle, and then downstream in an unnamed drainage to Sierra Well, to include Sierra Tank West and Sierra Tank East, then directly overland to Upper Turner Tank.

In this unit, bullfrogs are a continuing threat, and illegal border activity and associated law enforcement have resulted in watershed damage. A road on the berm of Upper Turner Tank is scheduled for improvement to access a surveillance tower operated by U.S. Customs and Border Protection. Frogs in this region have tested positive for chytridiomycosis

,

but the disease appears to have little effect on population viability.

Unit 5: Sycamore Canyon

This unit includes 262 ac (106 ha) of Coronado National Forest land and 7 ac (3 ha) of private lands along Atascosa Canyon through Bear Valley Ranch in the Pajarito and Atascosa Mountains, Santa Cruz County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Sycamore Canyon is the only significant site with moving water in recovery unit 1 to support breeding Chiricahua leopard frogs. Most other sites are livestock tanks or impounded springs. Sycamore Canyon, Bear Valley Ranch Tank, Rattlesnake Tank, and Atascosa Canyon downstream of Bear Valley Ranch were all occupied by Chiricahua leopard frogs at the time of listing. The occupancy status of the other sites at the time of listing is unknown. Sycamore Canyon, Yank Tank, North Mesa Tank, South Mesa Tank, and Bear Valley Ranch Tank are currently occupied. The current occupancy status of Rattlesnake Tank and Atascosa Canyon downstream of Bear Valley Ranch Tank is unknown. Proposed critical habitat includes approximately 6.35 mi (10.23 km) of Sycamore Canyon from Ruby Road to the international border, which supports frogs and breeding, although in the driest months (May and June) the stream dries to pools and tinajas (a term used in the American Southwest for water pockets formed in bedrock depressions that occur below waterfalls or are carved out by spring flow or seepage).

A number of livestock tanks in the region form a strong metapopulation with Sycamore Canyon. Proposed critical habitat includes the following tanks and their connecting drainages: (1) From Yank Tank downstream in an unnamed drainage to Sycamore Canyon; (2) from North Mesa Tank downstream in Atascosa Canyon to its confluence with Peñasco Canyon, then from that confluence downstream in Peñasco Canyon to Sycamore Canyon; (3) from Horse Pasture Spring downstream to Peñasco Canyon; (4) from Bear Valley Ranch Tank downstream in an unnamed drainage to Atascosa Canyon; (5) from South Mesa Tank downstream in an unnamed drainage to Peñasco Canyon; and (6) from Rattlesnake Tank downstream in an unnamed canyon to its confluence with another unnamed drainage, then upstream in that drainage to South Mesa Tank.

Bullfrogs have been a continuing problem in this unit, although recent control efforts seem to have eliminated them from Sycamore Canyon. Nonnative green sunfish (

Lepomis cyanellus

) have occasionally been found in Sycamore Canyon, as well. Pools critical to survival of frogs and tadpoles through the dry season, are sensitive to sedimentation and erosion upstream in the watershed of Sycamore Canyon. The earliest records of chytridiomycosis in the United States are from Sycamore Canyon (1972). A robust population of Chiricahua leopard frogs persists at this site despite the disease and periodic die-offs. Illegal border activity and associated law enforcement have resulted in many trails and new vehicle routes in the area, as well as trampling in the canyon.

Sycamore Canyon is designated a Research Natural Area by the Coronado National Forest and is closed to livestock grazing. Critical habitat is designated for the Sonora chub (

Gila ditaenia

) in Sycamore Canyon from Hank and Yank Spring (about 0.25 mi (0.40 km) downstream of the Ruby Road crossing) downstream to the international border, and in a 25-ft (7.6-m) strip on both sides of the creek (51 FR 16042; April 30, 1986). Much of this unit also lies within the Pajarita Wilderness area. These designations provide some level of protection to Chiricahua leopard frog habitats in Sycamore Canyon.

Unit 6: Peña Blanca Lake and Spring and Associated Tanks

This unit includes 202 ac (82 ha) and is all on Coronado National Forest lands, Santa Cruz County, Arizona. This area is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

This unit is a metapopulation that includes Peña Blanca Lake, Peña Blanca Spring, Summit Reservoir, Tinker Tank, Thumb Butte Tank, and Coyote Tank. These sites were all occupied in 2009. Chiricahua leopard frogs and tadpoles were found in Peña Blanca Lake in 2009 and 2010, after the lake had been drained and then refilled, which eliminated the nonnative predators. However, early in 2010, rainbow trout (

Oncorhynchus mykiss

) were restocked back into the lake, and plans are underway to reestablish a variety of warm water fishes, as well. Currently, the Service is working with project proponents to help design the sportfish project in a way that will allow persistence of Chiricahua leopard frogs, but whether this site retains the PCEs necessary for breeding will be evaluated in our final critical habitat determination.

In 2002, Chiricahua leopard frogs were only known to occur at Peña Blanca Spring. Occupancy status at the time of listing for the other sites is unknown. Proposed critical habitat also includes: (1) From Summit Reservoir directly southeast to a saddle on Summit Motorway, then downslope to an unnamed drainage and downstream in that drainage to its confluence with Alamo Canyon, then downstream in Alamo Canyon to its confluence with Peña Blanca Canyon, then downstream in Peña Blanca Canyon to Peña Blanca Lake, to include Peña Blanca Spring; (2) from Thumb Butte Tank downstream in an unnamed drainage to its confluence with Alamo Canyon; (3) from Tinker Tank downstream in an unnamed drainage to its confluence with Alamo Canyon, then downstream in Alamo Canyon to the confluence with the drainage from Summit Reservoir; and (4) from Coyote Tank downstream in an unnamed drainage to its confluence with Alamo Canyon, and then downstream in Alamo Canyon to the confluence with the drainage from Tinker Tank, to include Alamo Spring.

Nonnative introduced predators, particularly bullfrogs and sportfish, remain a serious threat in this region. A concerted effort was made in 2008-2010 to clear the area of bullfrogs. The effort appears to be successful, and Chiricahua leopard frogs have benefited. However, there is a continuing threat of reinvasion or introduction of bullfrogs. As discussed, sportfish at Peña Blanca Lake

are an additional threat. Frogs in this region test positive for chytridiomycosis; however, the disease appears to have little effect on population viability.

Recovery Unit 2 (Santa Rita-Huachuca-Ajos Bavispe, Arizona and Mexico)

Unit 7: Florida Canyon

This unit includes 4 ac (2 ha) and is all on Coronado National Forest lands in the Santa Rita Mountains, Pima County, Arizona. This unit is proposed as critical habitat because it is essential for the conservation of the species.

Chiricahua leopard frogs currently occupy this site; however, its occupancy status at the time of listing is unknown. A single frog was found in 2008, which was augmented with frogs from elsewhere in the Santa Rita Mountains in 2009. The site is too far from other known breeding populations to be part of a metapopulation (the next nearest population is about 5 mi (8 km) straight line distance away in Unit 8; hence, it will be managed as an isolated, robust population). PCE 1 is present and will be enhanced in 2010, with the addition of a steel tank for breeding. Included in the proposal is approximately 1,521 ft (463 m) of Florida Canyon from a silted-in dam to the downstream end of the Florida Workstation property.

Water is a limiting factor in this system, particularly during drought. Fire in the watershed could result in scouring and sedimentation in the pools important as habitat for the frog. The addition of a steel tank will provide dependable water for breeding that is safe from erosion or sedimentation events. Chyridiomycosis and introduced predators are potential threats, but neither has been recorded at this site.

Unit 8: Eastern Slope of the Santa Rita Mountains

This unit includes 172 ac (70 ha) of Coronado National Forest lands and 14 ac (6 ha) of private lands in the Greaterville area in Pima County, Arizona. This unit is proposed as critical habitat because it is essential for the conservation of the species.

Included in the proposed critical habitat designation are two metal troughs in Louisiana Gulch, Greaterville Tank, Los Posos Gulch Tank, and Granite Mountain Tank complex. The Granite Mountain Tank complex includes two impoundments and a well. All but Los Posos Gulch Tank are currently occupied breeding sites; however, the occupancy status at the time of listing for these sites is unknown. PCEs 1 and 2 are present. More than 60 frogs were observed at Los Posos Gulch Tank in 2008. It was once thought to be a robust breeding site; however, it dried, and the frogs disappeared in 2009. These four sites collectively form a metapopulation. A number of other sites in this region have been found to support dispersing Chiricahua leopard frogs; however, only a few frogs and no breeding have been observed at these sites, so they are thought to represent dispersing frogs. The occupancy status of these other sites at the time of listing is unknown. Proposed critical habitat also includes intervening drainages as follows: (1) From Los Posos Gulch upstream to a saddle, then downslope in an unnamed drainage to the confluence with another unnamed drainage, then upstream and south in that drainage to a saddle, and downslope through an unnamed drainage to its confluence with Ophir Gulch, then in Ophir Gulch to upper Granite Mountain Tank, to include an ephemeral tank near upper Granite Mountain Tank and a well; (2) from Greaterville Tank downstream in an unnamed drainage to Ophir Gulch; and (3) Louisiana Gulch from the metal tanks upstream to the headwaters of Louisiana Gulch then across a saddle and downslope through an unnamed drainage to its confluence with Ophir Gulch.

Surface water is a primary limiting factor in this unit. The breeding habitat at Louisiana Gulch, although limited to two 6.0-ft (1.8-m) diameter steel tanks, is dependable because it is fed by a well. The other tanks are filled by runoff and susceptible to drying during drought. Nonnative predators and chytridiomycosis are not known to be imminent threats in this area.

Unit 9: Las Cienegas National Conservation Area

This unit is in Pima County, Arizona, and includes 1,235 ac (500 ha) of Bureau of Land Management lands and 186 ac (75 ha) of Arizona State Land Department lands, including an approximate 4.33-mi (6.98-km) reach of Empire Gulch and 1.91 mi (3.08 km) of Cienega Creek, including the Cinco Ponds. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

At the time of listing, Empire Gulch was occupied; however the occupancy status of Cinco Ponds at that time is unknown. Currently, Chiricahua leopard frogs are extant at Empire Gulch and Cinco Ponds. Frogs breed in a reach of Empire Gulch near Empire Ranch. This reach includes: (1) Empire Gulch from a pipeline road crossing above the breeding site downstream to Cienega Creek; and (2) Cienega Creek from the Empire Gulch confluence upstream to the approximate end of the wetted reach and where the creek bends hard to the east, to include Cinco Ponds. An enclosed Chiricahua leopard frog facility exists along Empire Gulch and is used to headstart eggs and tadpoles for release to augment the wild population. Frogs may breed periodically at Cinco Ponds. These sites are too far (more than 8.0 mi (13 km) straight line distance) from the next nearest population, which is in Unit 8; thus the population(s) in Unit 9 currently acts as an isolated population(s).

The recovery program for the Chiricahua leopard frog at Las Cienegas is a collaborative, multi-partner approach that recently got a boost with a substantial grant from the National Fish and Wildlife Foundation. However, bullfrogs are present and represent a persistent problem. Chiricahua leopard frogs suffer from chytridiomycosis

in this unit, which has resulted in periodic die-offs; however, the frogs are persisting with the disease. Crayfish occur within a few miles and pose a significant threat if they reach Cienega Creek or Empire Gulch. The frog population in this unit is not robust.

Las Cienegas National Conservation Area is managed under the principles of multiple-use and ecosystem management for future generations. Empire Gulch and Cienega Creek downstream of its confluence with Empire Gulch is designated critical habitat for the endangered Gila chub (

Gila intermedia

) (70 FR 66663; November 2, 2005). The chub and the endangered Gila topminnow (

Poeciliopsis occidentalis

) occur in Cienega Creek adjacent to Empire Gulch. The Gila topminnow also occurs in Empire Gulch. Neither species occurs in Cinco Ponds. Where these species or critical habitat occur, some level of protection may be afforded to Chiricahua leopard frog habitat.

Unit 10: Pasture 9 Tank

This unit includes 0.5 ac (0.2 ha) and is a former cattle pond entirely on private lands of the San Rafael Ranch, San Rafael Valley, Santa Cruz County, Arizona. It is proposed as critical habitat because it is essential for the conservation of the species.

This unit was not known to be occupied at the time of listing; however, Chiricahua leopard frogs were established at this site through a reintroduction in 2009. The next nearest population is about a 10.5-mi (16.8-km), straight-line distance away in the Unit

11; hence, Pasture 9 Tank is being managed as an isolated population. PCE 1 is present in this unit.

The site is fenced with bullfrog exclusion fencing, which also excludes livestock, and the pond is equipped with a solar-powered pump and well that provides a continual source of water for the pond. The design of the fence allows Chiricahua leopard frogs to exit the fenced area, but they cannot return. Proposed critical habitat includes all areas within the fence. This is a cooperative project with the landowner through the Service's Partners for Fish and Wildlife Program. The landowner has also entered into a Safe Harbor Agreement for the Chiricahua leopard frog; however, bullfrogs are in the area and remain a threat if the fence is breached.

Chytridiomycosis is present in endangered Sonoran tiger salamander (

Ambystoma tigrinum stebbinsi

) populations in the San Rafael Valley, and the disease has caused mass die-offs and extirpations of Chiricahua leopard frogs in the nearby Huachuca Mountains; as a result, chytridiomycosis is considered a threat at Pasture 9 Tank. This unit is being considered for exclusion from the final rule for critical habitat under section 4(b)(2) of the Act (

see Application of Section 4(b)(2) of the Act

section below).

Unit 11: Scotia Canyon

This unit includes 70 ac (29 ha) in Scotia Canyon, Huachuca Mountain, Cochise County, Arizona, and is entirely on Coronado National Forest lands. This unit is proposed as critical habitat because it is essential for the conservation of the species.

The unit encompasses an approximate 1.36-mi (2.19-km) reach of the canyon with perennial pools, as well as a perennial travertine (a form of limestone) seep, a spring fed, perennial impoundment (Peterson Ranch Pond), and an ephemeral impoundment adjacent to Peterson Ranch Pond. There is also a perennial or nearly perennial impoundment in the channel downstream of the travertine seep. Breeding habitat occurs at Peterson Ranch Pond and possibly at other perennial or nearly perennial pools.

Chiricahua leopard frogs were reestablished in this canyon via a translocation in 2009; the last record of a Chiricahua leopard frog in the canyon before that was 1986. Scotia Canyon was not occupied at the time of listing. PCEs 1 and 2 are present.

Currently, this site is isolated from other populations, the nearest of which is in Unit 15, about a 4.4-mi (7.0-km), straight-line distance away over mountainous terrain. Hence this site is managed as an isolated population, but there is some potential for creating connectivity to the metapopulation in Unit 14 via population reestablishment in Garden Canyon at Fort Huachuca. Scotia Canyon, with its pond and stream habitats, has the potential to be a robust population.

This canyon, and sites around it, has been the subject of intensive bullfrog eradication and habitat enhancement work in preparation for reestablishing the Chiricahua leopard frog. However, bullfrog reinvasion is a significant, continuing threat, and other nonnative predators could potentially reach Scotia Canyon via natural or human assisted immigration. In addition, tiger salamanders (

Ambystoma mavortium

) from the Peterson Ranch Pond tested positive for chytridiomycosis in 2009; however, in 2010, the frogs appeared to be doing well in that same pond, and it is unclear as to whether tiger salamander have persisted at that pond. Nonetheless, disease has resulted in extirpations elsewhere in the Huachuca Mountains, and is considered a serious threat in Scotia Canyon. Further, heavy fuel loads could result in a catastrophic wildfire, which would have significant detrimental effects on the frog and its aquatic habitats. Finally, a road through the canyon is eroded in places and contributes sediment to the stream; it receives much use by recreationists and U.S. Customs and Border Protection.

The proposed critical habitat designation for the Chiricahua leopard frog largely overlaps that of critical habitat for the endangered plant Huachuca water-umbel (

Lilaeopsis schaffneriana

var.

recurva

). Several listed and candidate species have been recorded in Scotia Canyon. These occurrences of critical habitat and listed species provide some level of protection to Chiricahua leopard frog habitat in this unit.

Unit 12: Beatty's Guest Ranch

This unit includes 10 ac (4.0 ha) of private lands in Miller Canyon on the east slope of the Huachuca Mountains, Cochise County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Beatty's Guest Ranch is one of four proposed critical habitat units (12, 13, 14, and 15) which was considered to be populated by the Ramsey Canyon leopard frog, until the Ramsey Canyon leopard frog was determined to be the same species as the Chiricahua leopard frog in 2008 (Crothers 2008, p. 7). Frogs and habitat in these four units have been managed intensively since 1995. A conservation agreement and very active conservation partnership was formalized in 1997. The conservation agreement implements the Chiricahua leopard frog recovery plan in this portion of the Huachuca Mountains. More recently, landowners in this unit enrolled their lands in the Arizona Game and Fish Department's (AGFD) Safe Harbor Agreement with a Certificate of Inclusion. Currently, The Nature Conservancy is in the process of enrolling their Ramsey Canyon Preserve in Unit 14, as well. Because frogs would not exist on these properties but for reestablishment projects by the Service and AGFD with the permission of the landowners, Beatty's Guest Ranch and The Nature Conservancy's Ramsey Canyon Preserve have been assigned a zero baseline for frogs under the Safe Harbor Agreement.

Frogs were present in Unit 12 at the time of listing and are currently extant. This is a robust breeding population that inhabits a number of constructed ponds on the property. Frogs freely move among the ponds through an apple orchard, connecting streams, and overland. Beatty's Guest Ranch is too far from other populations (about a 3.0-mi (4.8-km), straight-line distance from Unit 14 over rugged terrain, or about 2.0 mi (3.2 km) along ephemeral or intermittent drainages and 1.7 mi (2.7 km) overland to Unit 13) to form a metapopulation, and because of presence of chytridiomycosis and population decline and extirpation associated with the disease in Units 13, 14, and 15, such connection is not desirable. As a result, Unit 12 is managed as an isolated, robust population. This is the most stable and robust population of Chiricahua leopard frogs known in recovery unit 2.

Given the presence of chytridiomycosis in Units 13, 14, and 15 and its apparent dire effects on Chiricahua leopard frog populations there, chytridiomycosis is an ever present threat in Unit 12. However, frogs at the Beatty's Guest Ranch have never tested positive for the disease. Factors may be acting at this site to prevent its establishment as an epizootic disease (an outbreak of disease affecting many animals of one kind at the same time). Because of the diligent management of the Beatty family, no other factors threaten this population. The frogs are present as a result of a translocation agreed to by the Beattys, who are signatories to the conservation agreement described above, and have also enrolled their property into a Safe

Harbor Agreement for the Chiricahua leopard frog. Under section 4(b)(2) of the Act, this unit is being considered for exclusion from the final rule for critical habitat (

see Application of Section 4(b)(2) of the Act

section below).

Unit 13: Carr Barn Pond

This unit includes 0.6 ac (0.3 ha) of Coronado National Forest lands in the Huachuca Mountains, Cochise County, Arizona. Carr Barn Pond is an impoundment with a small, lined pond with water provided from a well. During runoff events, the size of the pond expands considerably and then gradually shrinks back to the lined section.

This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs to support life-history functions essential for the conservation of the species.

As with Units 12, 14, and 15, this unit has been the subject of a conservation agreement and much intensive management for the Ramsey Canyon (=Chiricahua) leopard frog. The Coronado National Forest created and now maintains Carr Barn Pond consistent with the Ramsey Canyon (=Chiricahua) leopard frog conservation agreement, to which they are a signatory. This site was occupied at the time of listing and was occupied into 2009, but the population has since been eliminated, probably by chytridiomycosis. This site is too far away (3.4 mi (5.4 km) from Unit 14 and about 3.0 mi (4.8 km) from Unit 12 by way of a straight-line distance over rugged terrain) to be part of a metapopulation; hence, it is currently considered isolated. There is some potential for connecting it to Units 11, 14, and 15 (

see

discussion above), but additional habitat creation or enhancement and population reestablishment would be needed.

The unit has a history of nonnative predator problems and disease. We believe PCE 1 is present, but disease is a serious threat here that may be an impediment to viable frog populations. The population has been eliminated after chytridiomycosis die-offs three times; twice the population has subsequently been reestablished through translocations. Largemouth bass have been introduced illegally into the pond and then removed, and bullfrogs periodically invade the site but are promptly removed before they breed.

Unit 14: Ramsey and Brown Canyons

This unit includes 65 ac (26 ha) of private lands in Ramsey Canyon and 58 ac (24 ha) of Coronado National Forest in Brown and Ramsey Canyons, Huachuca Mountains, Cochise County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs to support life-history functions essential for the conservation of the species.

This unit along with other Units (12, 13, and 15) have been managed intensively for Ramsey Canyon (=Chiricahua) leopard frog conservation since 1995. This unit is managed as a metapopulation. Places where frogs have bred and that still retain PCE 1 include Ramsey Canyon, Trout and Meadow Ponds on private lands owned by The Nature Conservancy, and the Ramsey Canyon Box; and in Brown Canyon, the Wild Duck Pond, House Pond, and the Brown Canyon Box (on Coronado National Forest lands). PCEs 1 and 2 are present within this unit.

In addition to the breeding ponds, this critical habitat proposal also includes dispersal sites and corridors for connectivity among breeding ponds as follows: (1) From the top of the Box in Ramsey Canyon downstream to a dirt road crossing of Ramsey Canyon at the mouth of the canyon; (2) Brown Canyon from the Box downstream to the Wild Duck Pond and House Pond on the former Barchas Ranch; and (3) from the dirt road crossing of Ramsey Canyon directly overland to House Pond.

The Ramsey Canyon portion of the unit was not occupied at the time of listing, but Brown Canyon was occupied. Both canyons are considered currently occupied, but although frogs have bred at the Box in Brown Canyon, the site is too small to support more than just a few frogs. In addition, recent die-offs associated with chytridiomycosis have significantly reduced populations in both canyons. The House and Wild Duck ponds as well as Ramsey Canyon have a history of chytridiomycosis outbreaks. The Ramsey Canyon population has been eliminated twice and then reestablished; the Wild Duck and House Ponds have also undergone repeated disease-related declines and extirpations followed by reestablishments. The populations tend to do well for months or years after reestablishment only to experience epizootic (an outbreak of disease affecting many animals of one kind at the same time) chytridiomycosis outbreaks followed by declines or extirpation.

Additional threats in this unit include nonnative species, drying, sedimentation, and fire. Nonnative predators threaten populations at the House and Wild Duck Ponds, where bullfrogs have been found periodically and goldfish were once introduced. Those two ponds are buffered against drought and drying by a pipeline from a spring and a windmill. However, the Box in Brown Canyon is subject to low water and drying during drought. That later population depends upon immigration or active reestablishment for long-term persistence. The Trout and Meadow Ponds in Ramsey Canyon are fed by pipelines; thus the water supply is dependable. The Trout Pond could however be filled in with sediment during a flood. Further, a fire in the watershed could threaten aquatic breeding sites in both canyons.

Lands owned by The Nature Conservancy in Ramsey Canyon are known as the Ramsey Canyon Preserve and are managed for preservation of natural features and species, including the Chiricahua leopard frog. The Nature Conservancy has been an active participant in Chiricahua leopard frog recovery for many years; the Ramsey Canyon Preserve is currently in the process of being signed onto a Safe Harbor Agreement, and The Nature Conservancy signed the Ramsey Canyon leopard frog conservation agreement, which implements the Chiricahua leopard frog recovery plan in the Huachuca Mountains. Under section 4(b)(2) of the Act, the Ramsey Canyon Preserve is being considered for exclusion from the final rule for critical habitat (

see Application of Section 4(b)(2) of the Act

section below).

Recovery Unit 3 (Chiricahua Mountains-Malpai Borderlands-Sierra Madre, Arizona, New Mexico, and Mexico)

Unit 15: High Lonesome Well

This unit includes 0.4 ac (0.2 ha) of privately owned lands in the Playas Valley, Hidalgo County, New Mexico. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCE 1) to support life-history functions essential for the conservation of the species.

This unit consists of an elevated concrete tank into which Chiricahua leopard frogs were introduced prior to listing (Painter 2000, p. 15). The tank is supplied with water from a windmill and provides water for livestock. The site supports a robust breeding population, but is much too far from other populations to be part of a metapopulation (the nearest population is in Unit 17, 25.4 mi (40.6 km) to the west). Furthermore, although frogs can exit the tank, they cannot get back into the tank. As a result, it is managed as an isolated, robust population.

Chiricahua leopard frogs were present at the time of listing and are currently extant. The population is threatened by deterioration of the concrete tank, which needs repair or replacement. Catastrophic failure of the tank would result in loss of this population. Chytridiomycosis has not been detected at this site, but disease testing has been minimal. Nonnative predators have not been recorded. Because of the nature of the site, such predators could not colonize the tank on their own; they would have to be introduced.

Unit 16: Peloncillo Mountains

This unit includes 366 ac (148 ha) of Coronado National Forest lands and 289 ac (117 ha) of private lands in Hidalgo County, New Mexico. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Aquatic habitats proposed as critical habitat in this unit include Geronimo, Javelina, State Line, and Canoncito Ranch Tanks; Maverick Spring; and pools or ponds in the Cloverdale Cienega and along Cloverdale Creek below Canoncito Ranch Tank. Breeding occurs in State Line and Canoncito Ranch Tanks, and possibly other aquatic sites. Canoncito Ranch and Geronimo tanks were occupied at the time of listing. The occupancy status of the other sites at that time is unknown. All four of the tanks and Maverick Spring have recent records of frogs (2007 to the present) and are considered currently occupied. Frogs disperse from Canoncito Ranch Tank into Cloverdale Cienega and Cloverdale Creek when water is present. This unit is managed as a metapopulation.

Also included in this critical habitat proposal are intervening drainages and uplands needed for connectivity among these aquatic sites, including: (1) Cloverdale Creek from Canoncito Ranch Tank downstream to rock pools about 630 feet (192 m) below the Cloverdale Road crossing of Cloverdale Creek, including Cloverdale Cienega; (2) from Geronimo Tank downstream in an unnamed drainage to its confluence with Clanton Draw, then upstream to the confluence with an unnamed drainage, and upstream in that drainage to its headwaters, across a mesa to the headwaters of an unnamed drainage, then downslope through that drainage to State Line Tank; (3) from State Line Tank upstream in an unnamed drainage to a mesa, then directly overland to the headwaters of Cloverdale Creek, and then downstream in Cloverdale Creek to Javelina Tank; and (4) from Javelina Tank downstream in Cloverdale Creek to the Canoncito Ranch Tank, to include Maverick Spring.

Periodic drought dries most of the aquatic sites completely or to small pools, which limits population growth potential. Nonnative sportfish are present at Geronimo Tank and may preclude successful recruitment. Occurrence of chytridiomycosis in this area has not been investigated, but may also be a limiting factor.

Sky Island Alliance is working with partners to restore the Cloverdale Cienega, which should improve aquatic habitats for Chiricahua leopard frogs. The owner of the Canoncito Ranch has signed onto a Safe Harbor Agreement for the Chiricahua leopard frog. Under section 4(b)(2) of the Act, the private lands in Unit 16 are being considered for exclusion from the final rule for critical habitat (

see Application of Section 4(b)(2) of the Act

section below).

Unit 17: Cave Creek

This unit includes 234 ac (95 ha) of Coronado National Forest lands and 92 ac (37 ha) of private lands owned by the American Museum of Natural History in the Chiricahua Mountains, Cochise County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs to support life-history functions essential for the conservation of the species.

Included in the proposed critical habitat are an approximate 5.84-mi (9.41-km) reach of Cave Creek and associated ponds in or near the channel, from Herb Martyr Pond downstream to the eastern U.S. Forest Service boundary, to include John Hands Pond and a spring-fed pond at the Southwest Research Station. PCEs 1 and 2 are present. This site will be managed as a metapopulation.

Herb Martyr Pond is the type locality for the Chiricahua leopard frog; however, no frogs have been observed at the site since 1977. The pool behind the dam is entirely silted in, and pools at the base of the dam are probably not adequate for Chiricahua leopard frog survival or reproduction. However, with restoration this site could once again support Chiricahua leopard frogs. The pond below the dam at John Hands appears suitable for occupancy, but Chiricahua leopard frogs have not been recorded there since 1966. The spring-fed pond at the Southwest Research Station appears to be excellent habitat, but we have no record of the species occurring there. Chiricahua leopard frogs were occasionally seen in Cave Creek through 2002, and an egg mass observed in Cave Creek on the Southwest Research Station property indicates it may be suitable for breeding, although the creek dries to shallow pools in most years in May and June. This unit is not currently occupied by Chiricahua leopard frogs; however, the Southwest Research Station is headstarting tadpoles collected from Leslie Canyon NWR (Unit 18); they will be captively bred and released at the pond on the station's property as early as 2011.

Scarcity of water can occur in drought years; however, the pond at the Southwest Research Station is fed by a well and thus is buffered against drought. Bullfrogs occur to the east but have never been recorded in the unit. The current status and past history of chytridiomycosis in this unit are unknown; however, the pond at the Southwest Research Station is fed by a warm spring and could provide some buffer against the disease. Rainbow trout were present and occurred concurrently with Chiricahua leopard frogs at Herb Martyr Pond, but no trout are currently known in the unit.

The Southwest Research Station has signed a Safe Harbor Agreement for the Chiricahua leopard frog and is an active participant in recovery. The Service and AGFD are working with additional private landowners downstream of the proposed critical habitat to bring them into the Safe Harbor Agreement. Under section 4(b)(2) of the Act, the American Museum of Natural History lands are being considered for exclusion from the final rule for critical habitat (

see Application of Section 4(b)(2) of the Act

section below).

Unit 18: Leslie Creek

The unit consists of 26 ac (11 ha) of National Wildlife Refuge lands on Leslie Canyon NWR, Cochise County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCE 1) to support life-history functions essential for the conservation of the species.

This unit is a stream system with intermittent pools and two small impoundments. Its upstream limit is the Leslie Canyon NWR boundary, and its downstream limit is at the crossing of Leslie Canyon Road, an approximate stream distance of 4,094 ft (1,248 m).

Chiricahua leopard frogs were present in this unit at the time of listing and are currently extant. This population is too far (24.8 mi (36.7 km)) from the next nearest breeding site (North Tank in Unit 19) to be part of a metapopulation. Hence it is managed as an isolated population.

Drought and lack of pools are limiting factors in this unit. Chiricahua leopard frogs are positive for chytridiomycosis at this site, and although they are persisting with the disease, the population is not robust, and the effects of the disease may be responsible in part. Bullfrogs occur in ponds to the east, but have never been recorded in Leslie Creek.

The endangered Huachuca water-umbel, endangered Yaqui chub (

Gila purpurea

), and endangered Yaqui topminnow (

Poeciliopsis occidentalis sonoriensis

) all occur in Leslie Creek, and the area is managed to conserve the aquatic and riparian habitats of the canyon. A landowner adjacent to the the refuge has signed a Safe Harbor Agreement for the Chiricahua leopard frog and other species. With future habitat renovations and population reestablishments, there is some potential for developing additional populations of Chiricahua leopard frogs in this area, which could form a metapopulation with the Leslie Canyon population.

Unit 19: Rosewood and North Tanks

This unit includes 19 ac (8 ha) of private land and 78 ac (31 ha) of land owned by the Arizona State Land Department in the San Bernardino Valley, Cochise County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Included in this proposed unit are two livestock tanks (Rosewood and North Tanks) and drainages and uplands to allow for movement of frogs between them. North Tank is on private land, while Rosewood Tank and the connecting drainage are on Arizona State Land Department lands. Rosewood Tank was occupied at the time of listing, but North Tank was not. Both tanks are currently occupied. Rosewood Tank is a breeding population, and North Tank probably supports breeding. The North Tank is a recent (2008) reestablishment site for which breeding has not yet been documented. Two interconnected breeding sites do not make a metapopulation (four or more interconnected breeding sites are necessary, Service 2007, p. K-3); hence this unit is considered an isolated population.

The intervening drainages and uplands proposed as critical habitat are as follows: (1) From Rosewood Tank downstream in an unnamed drainage that is parallel to and just south of the Guadalupe Canyon Road to its confluence with a large unnamed drainage, then upstream in that drainage; (2) under Guadalupe Canyon Road and east to its confluence with a minor unnamed drainage; (3) upstream in that unnamed minor drainage to its headwaters; (4) then overland to the headwaters of another unnamed drainage; (5) downstream in that drainage to its confluence with the drainage containing North Tank; and (6) downstream in that drainage to North Tank.

Chytridiomycosis has not been recorded in this unit despite its presence nearby at San Bernardino NWR. High pH at Rosewood Tank may be a limiting factor for the disease organism. No nonnative predators have been found at either of these tanks. Rosewood Tank has been equipped with two small, concrete-lined refugia ponds fed by a well so that the frogs can persist at this site even if the livestock tank, which is filled by runoff, goes dry.

For many years, the owners of the Magoffin Ranch in this unit have made unprecedented efforts to maintain this population. The private and Arizona State Land Department lands in the proposal are covered by a Safe Harbor Agreement for the Chiricahua leopard frog. The Magoffin Ranch owners have worked tirelessly for the recovery of this species. Under section 4(b)(2) of the Act, lands in this unit are being considered for exclusion from the final rule for critical habitat (

see Application of Section 4(b)(2) of the Act

section below).

Recovery Unit 4 (Piñaleno-Galiuro-Dragoon Mountains, Arizona)

Unit 20: Deer Creek

This unit consists of 17 ac (7 ha) of Coronado National Forest, 69 ac (28 ha) of Arizona State Land Department lands, and 34 ac (14 ha) of private lands in the Galiuro Mountains, Graham County, Arizona. This unit is proposed as critical habitat because it is essential for the conservation of the species. PCEs 1 and 2 are present in this unit.

Included in proposed critical habitat are Home Ranch, Clifford's, Vermont, and Middle Tanks, a series of 10 impoundments on the Penney Mine lease, and intervening drainages, primarily Deer Creek, and associated uplands and ephemeral tanks that provide corridors for movement among these tanks. Breeding has been confirmed on Deer Creek above Clifford's Tank, and in Home Ranch and Vermont Tanks, and is suspected in the other three sites named above when water is present long enough for tadpoles to metamorphose into adults (3 to 9 months). Home Ranch Tank supports a robust or nearly robust population of Chiricahua leopard frogs. This unit functions as a metapopulation. Intervening drainages include: (1) Deer Creek from a point where it exits a canyon and turns abruptly to the east, upstream to its confluence with an unnamed drainage, upstream in that drainage to a confluence with four other drainages, upstream from that confluence in the western drainage to Clifford's Tank, upstream from that confluence in the west-central drainage to an unnamed tank, then directly overland southeast to another unnamed tank, then downstream from that tank in an unnamed drainage to the aforementioned confluence and upstream in that unnamed drainage to a saddle, and downstream from that saddle in an unnamed drainage to its confluence with an unnamed tributary to Gardner Canyon, and upstream in that unnamed tributary to Home Ranch Tank; (2) from the largest of the Penney Mine Tanks directly overland and southwest to an unnamed tank, and downstream from that tank in an unnamed drainage to the aforementioned confluence, to include another unnamed tank situated in that drainage; (3) from Vermont Tank directly overland and east to Deer Creek; and (4) from Middle Tank upstream in an unnamed drainage to a saddle, and then directly downslope to Deer Creek.

The primary threat to Chiricahua leopard frogs and their habitats in this unit is periodic drought that results in breeding sites drying out. During a severe drought in 2002, all but one of the waters in the unit dried out. The occupancy status of the unit at the time of listing is unknown. Frogs in this unit reportedly died for unknown reasons in the 1980s (Goforth 2005, p. 2), possibly indicative of chytridiomycosis; however, no Chiricahua leopard frogs have tested positive for the disease from this unit. The only nonnative aquatic predator recorded in this unit is the barred tiger salamander.

Recovery work has occurred in this unit, including headstarting of egg masses and reestablishment and augmentation of populations. The Service, AGFD, Arizona State Land Department, and an agate miner (Penney Mine Tanks) have drafted a conservation plan for managing habitats on the mine lease, but funds are lacking to implement that plan.

Unit 21: Oak Spring and Oak Creek

This unit consists of 27 ac (11 ha) of Coronado National Forest lands in the Galiuro Mountains, Graham County, Arizona. Oak Spring and Oak Creek are proposed as critical habitat because they

are essential for the conservation of the species.

The unit is currently occupied; however, its occupancy status at the time of listing is unknown. It is just north of Deer Creek (Unit 20) but is too far (about 1.6 mi (2.6 km)) overland (via straight-line distance) from the nearest aquatic sites (Home Ranch and Clifford's Tanks) in that unit. Connectivity is further complicated by a ridgeline between Oak Spring and Home Ranch Tank. Hence, this site is managed as an isolated population.

PCEs 1 and 2 are present in this unit. The site does not support enough frogs to be considered a robust population. This unit is an approximate 1.06-mi (1.71-km) intermittent reach of an incised canyon punctuated by pools of varying permanence, from Oak Spring downstream in Oak Creek to where a hiking trail intersects the creek. The largest pool, Cattail Pool, is permanent or nearly so and typically supports several Chiricahua leopard frogs and breeding. The reach proposed for critical habitat captures the area where Chiricahua leopard frogs have been seen.

The primary threat in this unit is extended drought during which all of the pools are subject to reduction or drying. Cattail Pool is spring-fed, and is likely the last pool to dry out. Oak Spring is also tapped for water developments, which may limit the capability of the site to support frogs. Chiricahua leopard frogs have been headstarted and released at this site to augment the population.

Unit 22: Dragoon Mountains

This unit includes 74 ac (30 ha) of Coronado National Forest lands in Cochise County, Arizona. This uit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Shaw Tank and Tunnel Spring in Middlemarch Canyon are proposed as critical habitat in this unit and are currently occupied breeding sites. The latter is a robust population that was occupied at the time of listing. Shaw Tank is a reestablishment site that was not known to be occupied in 2002.

Also included in the proposal as proposed critical habitat is Halfmoon Tank, which supported a robust population of Chiricahua leopard frogs until 2002. It dried or nearly dried that year and may or may not have supported Chiricahua leopard frogs at the time of listing. PCE 1 at Halfmoon Tank has been compromised by siltation and recent drought. The tank is in need of renovation so that it may again dependably hold water and support breeding.

Currently, not enough breeding sites exist to comprise a metapopulation (four are necessary) in this unit; however, with additional habitat creation or renovation, a metapopulation may be possible, which is needed for this recovery unit (the only other metapopulation is in Unit 20).

Also included in this critical habitat proposal are intervening drainages for connectivity, including Stronghold Canyon from Halfmoon Tank to Cochise Spring, then upstream in an unnamed canyon to Shaw Tank, and continuing upstream to the headwaters of that canyon, across a saddle and downstream in Middlemarch Canyon to Tunnel Spring.

Threats to the Chiricahua leopard frog and its habitat are primarily scarcity of suitable breeding habitat and loss of that habitat during drought. Tunnel Spring is spring-fed and thus buffered against drought; however, Shaw and Halfmoon Tanks are filled with runoff. Neither nonnative predators nor chytridiomycosis have been noted in these populations and habitats, although if introduced they would constitute additional stressors.

Recovery work, including headstarting of eggs collected from Tunnel Spring and establishment of a new population at Shaw Tank with reared tadpoles and frogs, has been accomplished in this unit, and the U.S. Forest Service's livestock permittee has been an enthusiastic participant in those recovery activities.

Recovery Unit 5 (Mogollon Rim-Verde River, Arizona)

Unit 23: Buckskin Hills

This unit includes 232 ac (94 ha) of Coconino National Forest lands in Yavapai County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Included in this proposed critical habitat unit are six tanks occupied at the time of listing (Sycamore Basin, Middle, Walt's, Partnership, Black, and Buckskin) that form a metapopulation. Frogs currently occur at Middle and Walt's Tanks. Also included in the critical habitat proposal are two tanks occupied in 2001 that probably dried out during a drought in 2002: Doren's Defeat and Needed Tanks. The former holds water well and is about 0.5 mi (0.8 km) from Partnership Tank and 0.67 mi (1.07 km) from Walt's Tank. Needed Tank may not hold water long enough for breeding, but it provides a stopover for dispersing frogs.

This proposed critical habitat also includes drainages and uplands likely used as dispersal corridors among these tanks, including: (1) From Middle Tank downstream in Boulder Canyon to its confluence with an unnamed drainage that comes in from the northwest, to include Black Tank, then upstream in that unnamed drainage to a saddle, to include Needed Tank, downstream from the saddle in an unnamed drainage to its confluence with another unnamed drainage, downstream in that drainage to the confluence with an unnamed drainage, to include Walt's Tank, and upstream in that unnamed drainage to Partnership Tank; (2) from Doren's Defeat Tank upstream in an unnamed drainage to Partnership Tank; (3) from the confluence of an unnamed drainage with Boulder Canyon west to a point where the drainage turns southwest, then directly overland to the top of Sycamore Canyon, and then downstream in Sycamore Canyon to Sycamore Basin Tank; and (4) from Buckskin Tank upstream in an unnamed drainage to the top of that drainage, then directly overland to an unnamed drainage that contains Walt's Tank.

The greatest threats are reintroduction of nonnative species and drought. Divide Tank, which is adjacent to Highway 260, has supported nonnatives in the past and is a likely place for future illegal stockings of fish or bullfrogs. If established there, nonnatives could spread to sites proposed herein as critical habitat. All of the tanks proposed as critical habitat are filled by runoff; hence, they are vulnerable to drying during drought. When the species was proposed for listing, the populations in the Buckskin Hills were unknown; however, during 2000-2001, frogs were found at 11 sites. After a severe drought in 2002, frogs only remained at Sycamore Basin and Walt's Tanks. Drilling a well to make one or more of the tanks less susceptible to drying is cost prohibitive because of the extreme depth to groundwater. Because the tanks depend on runoff, and as most tanks went dry in 2002, protecting more than the minimum four breeding sites needed for a metapopulation is warranted. Chytridiomycosis has not been found in any wild frogs in the Buckskin Hills; however, the disease occurs in Arizona treefrogs (

Hyla wrightorum

) and western chorus frogs (

Pseudacris triseriata

) less than 10 mi (16 km) to the east, and frogs collected from Walt's Tank

subsequently tested positive for the disease in captivity. It is unknown whether they contracted the disease in the wild or while captive.

Much recovery work has been accomplished in this unit, including captive rearing, population reestablishments, tank renovations, erosion control, fencing, and elimination of nonnative predators such as sportfishes and crayfish.

Unit 24: Crouch, Gentry, and Cherry Creeks, and Parallel Canyon

This unit includes 334 ac (135 ha) of Tonto National Forest lands, 64 ac (26 ha) of AGFD lands, and 6 ac (3 ha) of private lands in Gila County, Arizona. This unit is proposed as critical habitat because it was occupied at the time of listing and currently contains sufficient PCEs (PCEs 1 and 2) to support life-history functions essential for the conservation of the species.

Included as proposed critical habitat are Trail Tank, HY Tank, Carroll Spring, West Prong of Gentry Creek, Pine Spring, and portions of Cherry and Crouch Creeks, all of which provide breeding or potential breeding habitat. Also included are intervening drainages and uplands needed for connectivity among breeding sites, including: (1) Cherry Creek from Rock Spring upstream to its confluence with an unnamed drainage, upstream in that drainage and across a saddle, then downstream in an unnamed drainage to Trail Tank; (2) Crouch Creek from its headwaters just south of Highway 288 downstream to an unnamed drainage leading to Pine Spring, to include Cunningham Spring and Carroll Spring, then upstream in that unnamed drainage from Crouch Creek to Pine Spring; (3) from HY Tank downstream in an unnamed drainage to Cherry Creek, to include Bottle Spring; (4) from Cunningham Spring east across a low saddle to West Prong of Gentry Creek where the creek turns southwest; and (5) from Bottle Spring south over a low saddle to the headwaters of Crouch Creek.

At the time of listing, Chiricahua leopard frogs occurred in Crouch Creek, Carroll Spring, HY Tank, Bottle Spring, and West Prong of Gentry Creek. Trail Tank has nearly permanent water and is in the Parallel Canyon drainage, but close to the divide with Cherry Creek. In May 2010, it was renovated to remove a breeding population of bullfrogs and green sunfish. Additional followup removal of bullfrogs occurred in July 2010. Bullfrogs at the nearby ephemeral Roadside Tank were also eliminated in 2010. Once bullfrogs are confirmed absent, plans will move forward to translocate Chiricahua leopard frogs to Trail Tank.

Chiricahua leopard frogs were moved to Pine Spring in 2006, and habitat work was accomplished there to improve pool habitats. However, no frogs were observed during a site visit in May 2010. The connectivity of Pine Spring to Cunningham Spring and other sites upstream in Crouch Creek is complicated by a waterfall below Cunningham Spring; however, an overland route of less than a mile provides access around the waterfall.

Chiricahua leopard frogs were first noted in Cherry Creek in 2008, just before additional frogs were released into that site. Reproduction has been noted and frogs were observed in Cherry Creek in 2010.

Threats in this unit include predation by nonnative species, including bullfrogs, crayfish, and sportfish; predation by tiger salamanders (presumably native); chytridiomycosis, which was found in a Cherry Creek frog in 2009; and minimal water. None of the populations are robust due to the small size of breeding habitats. It is hoped that Trail Tank may provide enough aquatic habitat for a robust population. Other sites have renovation potential and could possibly in the future support robust populations, but none of the other sites currently have the PCEs due to presence of nonnative species or other factors.

This unit has received habitat work, renovations, nonnative species control, headstarting, population reestablishment, and population augmentation.

Unit 25: Ellison and Lewis Creeks

This unit includes 83 ac (34) of Tonto National Forest lands and 15 ac (6 ha) of private lands in Gila County, Arizona. This unit is proposed as critical habitat because it is essential for the conservation of the species. PCEs 1 and 2 are present in this unit.

Included in this critical habitat proposal are potential breeding sites at Moore Saddle Tank #42, Ellison Creek just east of Pyle Ranch, Lewis Creek downstream of Pyle Ranch, and Low Tank. Intervening drainages that provide connectivity among the latter three sites are also propos

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