Recovery Plan

for the

California Red-legged Frog

(Rana aurora draytonii)

Region 1

U.S. Fish and Wildlife Service

Portland, Oregon
Disclaimer

Recovery plans delineate reasonable actions that are believed to be required to recover and/or

protect listed species. Plans are published by the U.S. Fish and Wildlife Service, and

sometimes are prepared with the assistance of recovery teams, contractors, State agencies, and

others. Objectives will be attained and any necessary funds made available subject to

budgetary and other constraints affecting the parties involved, as well as the need to address

other priorities. Recovery plans do not necessarily represent the views nor the official positions

or approval of any individuals or agencies involved in the plan formulation, other than the U.S.

Fish and Wildlife Service. They represent the official position of the U.S. Fish and Wildlife

Service only after they have been signed by the Director, Regional Director, or Manager as

approved. Approved recovery plans are subject to modification as dictated by new findings,

changes in species status, and the completion of recovery tasks.

Literature Citation Should Read As Follows:

U.S. Fish and Wildlife Service. 2002. Recovery Plan for the California Red-legged Frog (Rana

aurora draytonii). U.S. Fish and Wildlife Service, Portland, Oregon. viii + 173 pp.

Additional copies may be purchased from:

Fish and Wildlife Reference Service

5430 Grosvenor Lane, Suite 110

Bethesda, Maryland 20814-2158

301-492-6403 or 1-800-582-3421

FAX: 301-564-4059

E-mail: fwrs@mail.fws.gov

http://fa.r9.fws.gov/r9fwrs/

The fee for the plan varies depending on the number of pages of the plan.

An electronic version of this recovery plan will also be made available at

http://www.r1.fws.gov/ecoservices/endangered/recovery/default.htm

ii
Acknowledgements

Primary Authors

Ina Pisani of the Sacramento Fish and Wildlife Office, U.S. Fish and Wildlife Service,

Sacramento, California acted as the Recovery Team Manager and prepared this recovery

plan. Recovery plan preparation was supervised and edited by Karen Miller, Diane Elam,

and Carmen Thomas, Sacramento Fish and Wildlife Office.

Acknowledgements

Grace McLaughlin of the Ventura Fish and Wildlife Office provided technical input on

many aspects of this recovery plan. In particular, Ms. McLaughlin provided assistance in

the delineation of recovery units and core areas and compiled Appendix B which

addresses the potential effects of contaminants on the California red-legged frog.

Each member of the California red-legged frog recovery team contributed valuable

information and assistance. In particular, we gratefully acknowledge the efforts of

Norman Scott and Galen Rathbun of the U.S. Geological Survey, Biological Resources

Division, Western Ecological Research Center, Piedras Blancas Field Station and Mark

Jennings for preparing the appendices that address pond management and

reestablishment of California red-legged frogs, and for being generous with their

technical assistance and time throughout the development of this recovery plan. We

thank them also for their thorough editorial review. In addition, we wish to thank

William Cunningham of the Natural Resources Conservation Service and Amy Lind of

the U.S. Forest Service for preparing the appendix that lists existing incentive programs.

The following individuals contributed significant information/assistance during recovery

plan preparation (California red-legged frog recovery team members are italicized):

Paul Barrett

Steven Bobzien

Maria Boroja

Patricia Bratcher

Sara Lee Chubb

David Cook

William W. Cunningham

Joseph Didonato

Gary Fellers

Darren Fong

Catherine Hibbard

Joshua Hoffman

Steve Holzman

Michael Jani

Mark Jennings

Douglas Krofta

Sheila Larsen

Amy Lind

Laurie Litman

Ivette Loredo

Ed Lorentzen

Sheila Massey

Curt McCasland

Tony McKinney

Grace McLaughlin

Meri Moore

Steven Morey

Dave Pereksta

Galen Rathbun

Mark Rentz

Lisa Roberts

Tamara Sasaki

Norman Scott

William Shook

John Steuber

Terry Strange

Kate Symonds

Brad Valentine

Phil Zentner

Illustrations are courtesy of the California Department of Fish and Game.

iii
Executive Summary

Current Species Status: The California red-legged frog (Rana aurora draytonii) is federally

listed as threatened. This subspecies of red-legged frog occurs from sea level to elevations of

about 1,500 meters (5,200 feet). It has been extirpated from 70 percent of its former range and

now is found primarily in coastal drainages of central California, from Marin County,

California, south to northern Baja California, Mexico. Potential threats to the species include

elimination or degradation of habitat from land development and land use activities and habitat

invasion by non-native aquatic species.

Habitat Requirements: The California red-legged frog requires a variety of habitat elements

with aquatic breeding areas embedded within a matrix of riparian and upland dispersal

habitats. Breeding sites of the California red-legged frog are in aquatic habitats including pools

and backwaters within streams and creeks, ponds, marshes, springs, sag ponds, dune ponds and

lagoons. Additionally, California red-legged frogs frequently breed in artificial impoundments

such as stock ponds.

Recovery Objective: The objective of this plan is to reduce threats and improve the

population status of the California red-legged frog sufficiently to warrant delisting.

Recovery Priority Number: 6C, per criteria published by Federal Register Notice (48 FR

43098; September 21, 1983). This number indicates a subspecies with high threats and low

recovery potential, in conflict with development projects.

Recovery Criteria: This subspecies will be considered for delisting when:

1) Suitable habitats within all core areas (described in Section II of this recovery plan) are

protected and/or managed for California red-legged frogs in perpetuity, and the ecological

integrity of these areas is not threatened by adverse anthropogenic habitat modification

(including indirect effects of upstream/downstream land uses);

2) Existing populations, throughout the range, are stable (i.e., reproductive rates allow for long

term viability without human intervention). Population status will be documented through

establishment and implementation of a scientifically acceptable population monitoring

program for at least a 15-year period, which is approximately 4 to 5 generations of the

California red-legged frog. This 15-year period will preferably include an average

precipitation cycle. An average precipitation cycle is a period when annual rainfall includes

average to 35 percent above-average through greater than 35 percent below-average and

back to average or greater. The direction of change is unimportant in this criterion.

3) Populations are geographically distributed in a manner that allows for the continued

existence of viable metapopulations despite fluctuations in the status of individual

populations (i.e. when populations are stable or increasing at each core area);

4) The subspecies is successfully reestablished in portions of its historic range such that at

least one reestablished population is stable/increasing at each core area where frogs are

currently absent; and

iv
Recovery Plan for the California Red-legged Frog v

5) The amount of additional habitat needed for population connectivity, recolonization, and

dispersal has been determined, protected, and managed for California red-legged frogs.

Actions Needed:

1. Protect known populations and reestablish populations.

2. Protect suitable habitat, corridors, and core areas.

3. Develop and implement management plans for preserved habitat, occupied watersheds, and

core areas.

4. Develop land use guidelines.

5. Gather biological and ecological data necessary for conservation of the species.

6. Monitor existing populations and conduct surveys for new populations.

7. Establish an outreach program.

Estimated Cost of Recovery: $10,031,500 plus costs that are not yet determined.

Date of Recovery: Delisting could occur by 2025 if recovery criteria have been met.
vi Recovery Plan for the California Red-legged Frog

“Smiley was monstrous proud of his

frog, and well he might be, for

fellers that had traveled and been

everywheres all said he laid over

any frog that they ever see.”

—Mark Twain, Celebrated Jumping Frog of

Calaveras County

(Most historians and scientists believe that the

California red-legged frog inspired Mark Twain

to write his short story.)
vii

Table of Contents

Executive Summary.. .............................................................................................................. iv

I. Introduction ...................................................................................................................... 1

A. Brief Overview .............................................................................................................. 1

B. Species Description ....................................................................................................... 2

C. Historic and Current Distribution. ................................................................................. 2

D. Habitat ......................................................................................................................... 12

E. Life History and Ecology ............................................................................................. 15

F. Reasons for Decline and Threats to Survival ............................................................... 17

G. Regulatory Protection and Conservation Measures .................................................... 30

H. Associated Species ...................................................................................................... 38

II. Recovery .......................................................................................................................... 45

A. Recovery Objectives and Strategies ............................................................................ 45

B. Recovery Criteria. ........................................................................................................ 46

C. Recovery Units ............................................................................................................ 47

D. Core Areas for Focused Recovery Efforts ................................................................... 50

E. Effects of the Recovery Strategy on Associated Species ............................................. 57

III. Outline of Recovery Actions .......................................................................................... 61

A. Guidance for Development of Watershed Management Plans and

Implementation of Recovery Tasks ........................................................................... 61

B. Recovery Tasks ......................................................................................................... 73

IV. Implementation Schedule .............................................................................................. 89

V. References ..................................................................................................................... 103

A. Literature Cited.......................................................................................................... 103

B. Personal Communications ......................................................................................... 113

C. In litt. References ....................................................................................................... 114

VI. Appendices .....................................................................................................................117

Appendix A. Glossary of Technical Terms ..................................................................... 117

Appendix B. Potential Contaminants Associated with California Red-legged Frog

Habitat....................................................................................................... 120

Appendix C. Maps of Core Areas Per County ............................................................... 130

Appendix D.Guidelines for Voluntary Pond Management for the Benefit of

California Red-legged Frogs..................................................................... 151

Appendix E. Private Landowner Incentives for Implementation of Conservation

Measures ................................................................................................... 154

Appendix F. Code of Practice to Reduce Spread of Disease and Parasites.................... 162

Appendix G. General Guidelines for Reestablishment of California Red-legged

Frog Populations ....................................................................................... 163

Appendix H. Summary of the Agency and Public Comment on the Draft Recovery

Plan for the California Red-legged Frog .................................................. 166
viii Recovery Plan for the California Red-legged Frog

List of Tables

Table 1. Number of streams per county where California red-legged frogs are present,

post-1985 ................................................................................................................. 1

Table 2. Sensitive fish and wildlife species associated with the California

red-legged frog ...................................................................................................... 37

Table 3. Threats to California red-legged frogs and recovery potential per recovery unit . 45

Table 4. Recovery goals and tasks aimed at eliminating threats ......................................... 48

Table 5. Selection criteria for core areas and importance of core areas for recovery ......... 54

Table 6. Core areas targeted for development and implementation of management and

protection plans for the California red-legged frog. .............................................. 74

List of Figures

Figure 1. Adult California red-legged frog ............................................................................. 2

Figure 2. California red-legged frog egg mass, tadpole, and new metamorph ....................... 3

Figure 3. Historic range of the California red-legged frog by county .................................... 4

Figure 4. Current range of the California red-legged frog by county ..................................... 5

Figure 5. California red-legged frog recovery units ............................................................... 6

Figure 6. Aerial view of breeding areas ................................................................................ 13

Figure 7. Breeding habitat at Ledson Marsh, Sonoma County ............................................. 14

Figure 8. Breeding pool and streamside vegetation in Round Valley Creek,

Contra Costa County ............................................................................................. 14

Figure 9. Dune swale breeding pond on Vandenberg Air Force Base, Santa Barbara

County and breeding habitat in a stockpond on Camp Ohlone Regional Park,

Alameda County .................................................................................................... 15

Figure 10. Comparison of the California red-legged frog and bullfrog .................................. 25

Figure 11. Predation by a bullfrog .......................................................................................... 26

Figure 12. California red-legged frog core area distribution .................................................. 51
1

I. Introduction

Table 1. Number of streams per county (north to south) where

California red-legged frogs are present, post-1985 (Natural Diversity

Database 2001, M. Jennings in litt. 1993).

County Number of Streams

El Dorado 2

Plumas 1

Butte 1

Yuba 1

Placer 1

Tehama 1

Napa 5

Sonoma 3

Solano 6

Marin 19

Contra Costa 21

San Joaquin 2

Alameda 12

San Francisco 1

San Mateo 22

Santa Clara 21

Santa Cruz 17

Stanislaus 2

Fresno 1

Merced 5

San Benito 5

Monterey 32

Kern 1

San Luis Obispo 30

Santa Barbara 35

Ventura 6

Los Angeles 2

Riverside 1

County Number of Streams

A. BRIEF OVERVIEW

The California red-legged frog (Rana aurora

draytonii) is endemic to California and Baja

California, Mexico, and its known elevational

range extends from near sea level to

elevations of about 1,500 meters (5,200 feet).

Nearly all sightings have occurred below

1,050 meters (3,500 feet) (Natural Diversity

Database 2001). The species has been

extirpated from 70 percent of its former range

and now is found primarily in coastal

drainages of central California, from Marin

County, California, south to northern Baja

California, Mexico, and in isolated drainages

in the Sierra Nevada, northern Coast, and

northern Transverse Ranges (U.S. Fish and

Wildlife Service 1996a). Populations remain

in approximately 256 streams or drainages in

28 counties (Table 1).

The California red-legged frog is threatened

within its remaining range, by a wide variety

of human impacts to its habitat, including

urban encroachment, construction of

reservoirs and water diversions,

contaminants, agriculture, and livestock

grazing. These activities can destroy, degrade,

and fragment habitat. The introduction of

non-native predators and competitors also

continues to threaten the viability of many

California red-legged frog populations.

The California red-legged frog was included

as a Category 1 candidate species in our (U.S.

Fish and Wildlife Service) November 21,

1991, Animal Notice of Review (U.S. Fish

and Wildlife Service 1991). On January 29,

1992, we received a petition from Dr. Mark

R. Jennings, Dr. Marc P. Hayes, and Mr. Dan

Holland to list the California red-legged frog.

On October 5, 1992, we published a 90-day

petition finding (U.S. Fish and Wildlife

NOTE: In this document the term “frog”

refers to the California red-legged frog unless

otherwise indicated.

Service 1992) with substantial information

indicating the requested action may be

warranted. On July 19, 1993, we published a

12-month finding on the petitioned action

(U.S. Fish and Wildlife Service 1993)

indicating that listing of the California redlegged frog was warranted and that a

proposed rule would be published promptly.

On February 2, 1994, we published a

proposal to list the California red-legged frog

as an endangered species (U.S. Fish and

Wildlife Service 1994a). Based on

information received during the comment

period on the proposed rule, we determined

the California red-legged frog to be a

threatened species; the listing was effective

on June 24, 1996 (U.S. Fish and Wildlife

Service 1996a). The recovery priority number

of the California red-legged frog is 6C,

indicating a subspecies with a high degree of

threat and low recovery potential. Recovery
2 Recovery Plan for the California Red-legged Frog

priority numbers are based on criteria

published by Federal Register Notice (48 FR

43098; September 21, 1983).

B. SPECIES DESCRIPTION

Class - Amphibia

 Order - Anura

 Family - Ranidae

 Genus - Rana

 Species - Rana aurora

 Subspecies - Rana aurora draytonii

The California red-legged frog (Rana aurora

draytonii) is one of two subspecies of the redlegged frog (Rana aurora). The other

subspecies is the northern red-legged frog (R.

a. aurora). The northern red-legged frog

ranges from Vancouver Island, British

Columbia, Canada, south along the Pacific

coast, west of the Cascade ranges to northern

California. Some red-legged frogs found in

the intervening areas (southern Del Norte to

northern Marin County along the Coast

Range), exhibit intergrade characteristics of

both subspecies (Hayes and Krempels 1986).

The two subspecies, and intergrades of the

subspecies, may

occur together in

some areas such as

the vicinity of Point

Reyes National

Seashore in Marin

County, and portions

of Sonoma County.

The California redlegged frog is the

largest native frog in

the western United

States (Wright and

Wright 1949). Adult

females attain a

significantly longer

body length than

males (138

millimeters [5.4

inches] versus 116

millimeters [4.5

inches] snout-urostyle length) (Hayes and

Miyamoto 1984). The posterior abdomen and

hind legs of adults are often red or salmon

pink; the back is characterized by small black

flecks and larger irregular dark blotches with

indistinct outlines on a brown, gray, olive, or

reddish-brown background color. Dorsal

spots usually have light centers (Stebbins

1985). Dorsolateral folds (the ridges of skin

along the back) are prominent (Figure 1).

Larvae (tadpoles) range from 14 to 80

millimeters (0.6 to 3.1 inches) in length, and

the background color of the body is dark

brown or olive with darker spots (Figure 2)

(Storer 1925). A line of very small, indistinct

gold-colored spots becomes the dorsolateral

fold (G. Rathbun in litt. 1998).

Several morphological and behavioral

characteristics differentiate the two

subspecies of red-legged frogs. Adult

California red-legged frogs are larger than

northern red-legged frogs by 35 to 40

millimeters (1.4 to 1.6 inches) (Hayes and

Miyamoto 1984). Dorsal spots of northern

red-legged frogs usually lack the light centers

that are common to California red-legged

frogs (Stebbins 1985). The southern

subspecies (California red-legged frog) has

paired vocal sacs and calls in air, whereas the

northern subspecies (northern red-legged

frog) lacks vocal sacs and calls under water

(Hayes and Krempels 1986, Licht 1969).

Female California red-legged frogs deposit

egg masses (Figure 2) on emergent vegetation

so that the masses float on the surface of the

water (Hayes and Miyamoto 1984) although

biologists from the East Bay Regional Park

District have seen submerged egg masses

throughout the egg development stage on

numerous occasions (J. DiDonato in litt.

2000). Northern red-legged frogs also attach

their eggs to emergent vegetation, but the

mass is submerged (Licht 1969). California

red-legged frogs breed from November

through early April (Storer 1925) and

northern red-legged frogs breed from January

through March (Nussbaum et al. 1983).

C. HISTORIC AND CURRENT DISTRIBUTION

It is believed that before the arrival of

Europeans on the west coast of North

America, the California red-legged frog was

common in coastal habitats from the vicinity

Figure 1. Adult

California redlegged frog.

Photo © Steven Bobzien
Recovery Plan for the California Red-legged Frog

3

of Point Reyes National Seashore, Marin

County, California, and inland from the

vicinity of Redding, Shasta County,

California, southward to northwestern Baja

California, Mexico (Jennings and Hayes

1985, Hayes and Krempels 1986).

Historically, the California red-legged frog

was known from 46 counties (Figure 3) but

the taxon is now extirpated from 24 of these

(U.S. Fish and Wildlife Service 1996a).

The California red-legged frog is now known

only from isolated localities in the Sierra

Nevada, northern Coast, and northern Transverse Ranges. It is believed to be nearly

extirpated from the southern Transverse and

Peninsular ranges. This species is still

common in the San Francisco Bay area

(including Marin County) and along the

central coast (Figure 4) ( Natural Diversity

Data Base 2001, Jennings in litt. 1998a). It is

still present in Baja California, Mexico, but

this recovery plan does not address

populations in Mexico.

The following paragraphs discuss, in general,

the status of the California red-legged frog in

each of the recovery units (north to south).

Briefly, there are eight recovery units (Figure

5). These include the following regions:

Sierra Nevada Foothills and Central Valley;

North Coast Range Foothills and Western

Sacramento River Valley; North Coast and

North San Francisco Bay; South and East San

Francisco Bay; Central Coast; Diablo Range

and Salinas Valley; Northern Transverse

Ranges and Tehachapi Mountains; and

Southern Transverse and Peninsular Ranges.

Recovery units are identified and described in

more detail below and in the Recovery

chapter (Section II.C). Detailed locality

information is available through the

California Department of Fish and Game’s

Natural Diversity Database (Natural Diversity

Database 2001).

Under the discussion of each recovery unit,

watersheds occupied by the California redlegged frog are listed; a watershed is

considered occupied when the presence of the

species is confirmed. Watersheds are used

here because California red-legged frogs can

be found in a range of habitats within a

Figure 2. California red-legged frog egg

mass (top)

Photo © David Cook Tadpole (center)

Photo © Steven Bobzien

New metamorph

(bottom)

Photo © Robert Snow
4 Recovery Plan for the California Red-legged Frog

watershed (e.g., stock ponds, creeks) and

because they may be known from a single

location or numerous locations within a

watershed. Thus, an occupied watershed

refers to an assumed network of habitat areas,

populations, and site-specific localities.

Occupied drainages or watersheds include all

of the bodies of water that support frogs (i.e.,

streams, creeks, tributaries, associated natural

and artificial ponds, and adjacent drainages),

and habitats through which frogs can move

(i.e., riparian vegetation, uplands). Where

frogs are known from a particular location

within a drainage, the more specific term

“locality” is used (e.g., the Pescadero Marsh

locality or the Spivey Pond locality versus the

broader Scott Creek drainage).

Because populations of frogs may be

extirpated with some frequency, occurrence

data may not adequately describe the status of

the species in a region. This limitation may be

the result of a lack of long term survey data, a

lack of complete survey data (due to

restricted access to private lands), and

fluctuations in population numbers. The

numbers at a site or series of sites can vary

widely from year to year. When conditions

are favorable, California red-legged frogs can

experience extremely high rates of

reproduction and produce large numbers of

dispersing young and a concomitant increase

in number of occupied sites. Conversely,

frogs may temporarily disappear from a

normally occupied area. At sites where frogs

seem absent, long-term monitoring is

necessary to determine if these sites are

recolonized or “rescued” by dispersers from

nearby subpopulations. Therefore, the

information on distribution and status should

be understood within the context of the larger

metapopulation scale (Scott and Rathbun in

litt. 1998). In this plan, metapopulations are

considered collections of populations that are

Figure 3. Historic

range of the

California redlegged frog in the

United States by

county.
Recovery Plan for the California Red-legged Frog 5

linked by migrants (i.e., dispersers), allowing

for recolonization of unoccupied habitat

patches after local extinction events.

Sierra Nevada Foothills and Central Valley.

The California red-legged frog was probably

extirpated from the floor of the Central Valley

before 1960 (U.S. Fish and Wildlife Service

1996a). The last verifiable record of this

species on the valley floor was a sighting in

Lodi (San Joaquin County) in 1957, and the

last record of a reproducing population on the

valley floor is from the vicinity of Gray

Lodge Wildlife Area (Butte County) around

1947, although this record is unverified

(Jennings et al. in litt. 1992). Elimination of

the frog from the floor of the valley was

particularly significant in that it isolated

Sierra-Nevada foothill populations that may

have depended on immigrants from the valley

floor (Jennings et al. in litt. 1992). However,

California red-legged frogs may never have

been widespread on the valley floor as

specimen-based records are scarce north of

the Kern River drainage.

California red-legged frogs historically

occupied portions of the western slope of the

Sierra Nevada from Shasta County south to

Tulare County, but these populations have

been fragmented and nearly eliminated. In

1960, isolated populations were known from

at least 30 Sierra Nevada foothill drainages

bordering the Central Valley. Records show

that the lower elevations of some National

Forests and Yosemite National Park were

once occupied by California red-legged frogs

(M. Jennings et al. in litt. 1992). Adjacent to

and in the vicinity of the Plumas National

Forest (Butte, Yuba, and Plumas Counties),

many sightings of California red-legged frogs

were reported in the early 1960s near Lake

Oroville. Specifically, frogs were verified

from the North Fork Feather River and the

Figure 4. Current

range of the

California redlegged frog in the

United States by

county.
6 Recovery Plan for the California Red-legged Frog

Figure 5. California

red-legged frog

recovery units.

Recovery Units

1. Sierra Nevada Foothills and Central Valley

2. North Coast Range Foothills and

Western Sacramento River Valley

3. North Coast and North San Francisco Bay

4. South and East San Francisco Bay

5. Central Coast

6. Diablo Range and Salinas Valley

7. Northern Transverse Ranges and Tehachapi

Mountains

8. Southern Transverse and Peninsular Ranges
Recovery Plan for the California Red-legged Frog 7

South Fork Feather River in 1961. In El

Dorado County, records exist for Rock Creek

in 1974 and Traverse Creek in 1975. Within

the vicinity of the Stanislaus National Forest,

California red-legged frogs were seen in San

Antonio Creek (Calaveras County) in 1975,

in Jordon Creek in 1967, and in Piney Creek

from 1972 to 1984 (Mariposa County).

Within the vicinity of the Tuolumne River,

many historic sites exist. For example, a

collection from the Mather vicinity was taken

in 1922, and again in 1945. Within Yosemite

National Park, collections were made from

Gravel Pit Lake (about 1,500 meters [5,000

feet]) in 1940, Swamp Lake (1,500 meters

[5,000 feet]) from 1938 to 1941, and Miguel

Meadows (1,600 meters [5,200 feet]) in 1939

(M. Jennings et al. in litt. 1992). These

collections represent the highest elevation

records for the California red-legged frog in

the Sierra Nevada. No confirmed sightings

have been observed or collected in the

Tuolumne River drainage for several decades.

In the southernmost Sierran foothills, frogs

were historically located within Kern County,

particularly in streams and irrigation ditches

near Bakersfield (Natural Diversity Data Base

2001, Jennings in litt. 1998a).

Currently, only a few drainages in the

foothills of the Sierra Nevada are known to

support California red-legged frogs,

compared to over 60 known historic localities

and 18 historic sites where specimens were

collected (Jennings and Hayes 1992, Barry

1999). In 1991, California red-legged frogs

were observed at Pinkard Creek in Butte

County (1,200 meters [3,500 feet]) (Hayes

1991). However, intensive surveys in

subsequent years have failed to reveal

additional observations of this species. In

recent surveys a population of mountain

yellow-legged frogs (Rana muscosa) was

observed, suggesting that the original

observation may have been a mountain

yellow-legged frog misidentified as a

California red-legged frog. Additional

locations in Butte County include French and

Indian Creeks. The French Creek population,

also referred to as the Swayne Hill/Chino

Creek population, was discovered in 1997; at

least a few hundred adults plus tadpoles and

juveniles have been observed and

reproduction appears to be highly successful

at this site (S. Barry in litt. 2000). California

red-legged frogs have been observed on

Indian Creek, near the town of Woodleaf

from 1973 to 1983 (Jennings et al. in litt.

1992). Each of these Butte County

populations is located on private lands,

adjacent to the Plumas National Forest. An

additional site in Butte County was located in

2000, on the Feather River Ranger District of

the Plumas National Forest on a tributary to

the North Fork Yuba River west of New

Bullards Bar Reservoir (C. Roberts pers.

comm. 2000, Barry 2000). In El Dorado

County near Placerville, a confirmed

population of California red-legged frog was

discovered in an impoundment (Spivey Pond)

in the North Fork of Weber Creek. In 2 years

of surveys at this site (1997 and 1998), adults,

egg masses, and tadpoles have been observed.

In 2001, a California red-legged frog was

documented near the confluence of Rubicon

River and the Middle Fork of the American

River in Placer County (G. Fellers in litt.

2001). This locality is on U.S. Forest Service

land. Much of the Sierra Nevada range is

unsurveyed, particularly on private lands, and

therefore the true status in this region is

largely unknown.

North Coast Range Foothills and Western

Sacramento River Valley. Historically, the

California red-legged frog was found in

several counties in this region. In the 1960s,

frogs were found in Glenn County east of Elk

Creek and in many drainages in Colusa

County. In 1986 and 1987, California redlegged frogs were reported in Sunflower

Gulch and Cottonwood Creek, west of Red

Bluff (Tehama County), but subsequent

surveys documented only bullfrogs (Rana

catesbeiana) (M. Jennings pers. comm.

1998). Within the vicinity of Clear Lake

(Lake County), records exist from 1961 near

the town of Hobergs, on Cold Creek. Barry

(in litt. 2000) observed California red-legged

frogs along Pope Creek and several

tributaries near Pope Valley in the Putah

Creek drainage throughout the 1970s and

1980s, and the habitat in this area remains

unaltered. There are three confirmed sightings

of this species in upper Napa County: from

1983, along Highway 128 between Highway
8 Recovery Plan for the California Red-legged Frog

121 and Wragg Canyon Road, and from 1992

and 1997, along nearby Steele Creek which is

a tributary to Lake Berryessa (S. Barry in litt.

2000). Recently, unverified sightings have

been reported in the vicinity of the Stebbins

Cold Canyon Ecological Reserve, Cache

Creek, and tributaries to Clear Lake (Lake

County) (M. Jennings pers. comm. 1998).

California red-legged frogs were also

documented in 1998 in a tributary to

American Canyon Creek in lower Napa

County (Natural Diversity Database 2001).

North Coast and North San Francisco Bay.

Significant numbers of California red-legged

frogs occur in small coastal drainages, ponds,

and man-made stockponds in the vicinity of

Point Reyes, including Point Reyes National

Seashore and Golden Gate National

Recreation Area (Marin County). For

example, large numbers of frogs occur in

Olema Marsh and the general vicinity of

Drakes Estero (Point Reyes National

Seashore). Many areas within the vicinity of

Mount Tamalpais and the Tiburon peninsula

(Marin County) also support California redlegged frogs, including Tennessee Valley

(Natural Diversity Database 2001, D. Fong in

litt. 1998).

A large breeding population is located at

Ledson Marsh in Annadel State Park

(Sonoma County). Also in Sonoma County,

two sightings of California red-legged frogs

have been verified near Sears Point at the

junction of Highway 37 and Lakeville Road

and the junction of Highway 37 and Highway

121 (Natural Diversity Database 2001).

In Solano County, there are three known

occurrences of California red-legged frogs

near Suisun Marsh (e.g., Sulphur Springs

Creek). Several localities are recorded near

the cities of Fairfield, Cordelia, American

Canyon, and Vallejo (Natural Diversity

Database 2001). Most remaining known

occurrences in the vicinity of southern Solano

County are threatened by proposed

development (C. McCasland in litt. 1998a).

South and East San Francisco Bay. In the

late 1800s and early 1900s, California redlegged frogs were reported in various areas of

San Francisco County including Lake

Merced, Golden Gate Park, and the Presidio.

The most recent sighting was in 1993, near

Strybing Arboretum in Golden Gate Park.

These populations may have been introduced

for commercial harvesting or may be relics of

a larger metapopulation. Currently, it is likely

that these populations face such severe

barriers that dispersal between populations

may be precluded. Canals within the West of

Bayshore parcel, near the San Francisco

International Airport in San Mateo County,

currently support California red-legged frogs.

This population experienced a decline over

the past several years due to site management

activities and tidal influences (U.S. Fish and

Wildlife Service 1996b). However, data

collected at the site since 1996 indicate that

the localized population contained more

individuals than previously thought.

Numerous individuals of all size classes have

been observed and few bullfrogs are present.

Breeding has been confirmed in some

seasonal impoundments and within the canal

system. The population, however, is isolated

by residential development (M. Allaback in

litt. 2000).

Contra Costa and Alameda Counties contain

the majority of known California red-legged

frog localities within the San Francisco Bay

area, although they seem to have been nearly

eliminated from the western lowland portions

of these counties (west of Highway 80 and

Highway 580), particularly near urbanization.

California red-legged frogs still occur in

small isolated populations in the East Bay

foothills (between Highway 580 and

Highway 680), and are thriving in several

areas in the eastern portions of Alameda and

Contra Costa Counties. Numerous ponds and

creeks in Simas Valley (Contra Costa County)

support California red-legged frogs (Dunne

1995). This area, owned and managed in part

by East Bay Municipal Utility District,

includes Rodeo and Pinole Creeks, and is

connected with Briones and Wildcat Canyon

Regional Parks (East Bay Regional Park

District). On East Bay Regional Park lands,

sizeable breeding populations are found at

Pine Creek (Diablo Foothills Regional Park/

Castle Rock Regional Recreation Area), Sand

Creek (Black Diamond Mines Regional
Recovery Plan for the California Red-legged Frog 9

Park), and Round Valley Creek (Round

Valley Regional Preserve) (S. Bobzien in litt.

1998). Recently, frogs have been sighted in

small ponds and seeps in the foothills of

Mount Diablo (M. Westphal pers. comm.

1998). California red-legged frogs are present

in Kellogg Creek watershed and its tributaries

upstream of Los Vaqueros Reservoir and

downstream to Vasco Road in eastern Contra

Costa County. Here, 87 of 91 stockponds and

mitigation wetlands have reproducing

populations. Recent surveys (September

2000) recorded nearly 3,000 individuals.

Conservative estimates for the total

population range from 7,000 to as high as

10,000 post-metamorph frogs (J. Alvarez in

litt. 2000). Many localities occur in Corral

Hollow Creek, in San Joaquin County, and

near the San Joaquin/Alameda County border.

In the Corral Hollow watershed, frogs are

found in the California Department of Fish

and Game’s Corral Hollow State Ecological

Reserve, although this Reserve is currently

threatened by siltation possibly caused and/or

exacerbated by an off-road vehicle park,

livestock grazing, and urban development upand downstream (M. Jennings in litt. 1993,

Jennings and Hayes 1994). Adult frogs have

been observed in Upper Alameda Creek

(Sunol Regional Wilderness) and also in

many of the creeks from this area, south to

Henry W. Coe State Park (e.g., Arroyo Hondo

and Sulphur, Smith, Isabel, and San Felipe

Creeks) (Santa Clara County). California redlegged frogs currently occupy many ponds

and creeks within Henry W. Coe State Park in

Santa Clara County (M. Jennings et al. in litt.

1992, K. Freel in litt. 1998) and are abundant

in many ponds in the Palassou Ridge area

south of Henry W. Coe State Park (L. Serpa

in litt. 2000).

Central Coast. The central coast from San

Francisco to Santa Barbara County supports

the greatest number of currently occupied

drainages. South of San Francisco, many

California red-legged frogs occur in

tributaries to Crystal Springs Reservoir and

adjacent lands (San Mateo County) (Natural

Diversity Database 2001). Most coastal

streams and ponds (natural and artificial)

from Pacifica south to Half Moon Bay (San

Mateo County) support this species (S.

Larson pers. comm. 1998). Pescadero Marsh

and Año Nuevo State Reserve (San Mateo

County) support large numbers of California

red-legged frogs; Pescadero Marsh is

considered one of the few places, throughout

the range, to support more than 350 adult

frogs. Almost all coastal drainages from the

Santa Cruz/San Mateo County line south to

the city of Santa Cruz are occupied by

California red-legged frogs. Wilder Ranch

State Park (Santa Cruz County) also supports

this species. The frogs occur in the Carmel

River watershed and most of its tributaries

(Natural Diversity Database 2001, EIP

Associates 1993); Rancho San Carlos, a

private ranch on the upper portion of the

Carmel River Valley is another locality where

more than 350 adults have been observed (M.

Jennings et al. in litt. 1992).

This species is widespread in Monterey

County; nearly all coastal drainages from

Garrapata Creek south to Salmon Creek,

including the Little and Big Sur drainages and

the vicinity of Pfeiffer Beach, support frogs.

In San Luis Obispo County, California redlegged frogs are found in many streams, stock

ponds, dune ponds, and springs on the coastal

plain and western slopes of the Santa Lucia

Range from San Carpoforo Creek in the north

to the Santa Maria River in the south. Sites

include Pico, Little Pico, and Toro Creeks;

Pico Pond; and San Simeon, Santa Rosa,

Chorro, and Arroyo Grande Creeks. On Camp

San Luis Obispo of the California National

Guard, frogs occur in Whiskey Spring,

tributaries to Chorro Creek and Chorro

Reservoir, and other sites (Jennings et al. in

litt. 1992, U.S. Fish and Wildlife Service

1996a).

Diablo Range and Salinas Valley. California

red-legged frogs were once widespread and

abundant in the inner Coast ranges between

the Salinas River system and the San Joaquin

Valley. Currently, no more than 10 percent of

the historic localities within the Salinas River

hydrographic basin and inner Coast ranges

(between the Salinas basin and the San

Joaquin River south of Pacheco Creek

drainage) still support this species (Jennings

and Hayes 1994).
10 Recovery Plan for the California Red-legged Frog

On the eastern side of the Diablo Range, there

are several occurrences of red-legged frogs

including Mine Creek in Fresno and Merced

Counties; and Piedra Azul Creek and North

Los Banos Creek in Merced County. Large

populations have been recently reported on

Romero Ranch, and potential habitat exists on

the Simon Newman Ranch. These ranches are

located between Henry W. Coe State Park and

San Luis Reservoir. The Nature Conservancy

purchased these sites; it has since sold the

Romero Ranch and soon will sell Simon

Newman Ranch with rare species protection

assured through conservation easements.

South of Henry W. Coe State Park and San

Luis Reservoir, California red-legged frogs

are found in Quien Sabe and Tres Pinos

creeks, the Pajaro and San Benito rivers, and

the general vicinity of Hollister (San Benito

County) such as Santa Ana Creek,

Tequisquita Slough, and the Hollister Hills

State Vehicular Recreation Area. Numerous

populations exist in Pinnacles National

Monument, particularly in Chalome and Bear

Gulch Creeks. (Natural Diversity Data Base

2001, M. Jennings in litt. 1998a).

The Elkhorn Slough watershed (Monterey

County) currently supports this species.

Within this area, adult California red-legged

frogs were observed at McClusky Slough in

1996; this is a site where restoration efforts

for the endangered Santa Cruz long-toed

salamander (Ambystoma macrodactylum

croceum) are ongoing. Several adult

California red-legged frogs have been

observed in the Salinas River drainage (M.

Jennings in litt. 1998). On Fort Hunter

Liggett Military Reserve, no current or

historic records of California red-legged frogs

exist, but surveys are being conducted in this

area which includes the Nacimiento and San

Antonio Rivers (G. McLaughlin pers. comm.

1998).

Northern Transverse Ranges and Tehachapi

Mountains. On the Santa Maria River,

California red-legged frogs occur up- and

downstream of Twitchell Reservoir (Natural

Diversity Database 2001). To the south, the

lower drainage basin of San Antonio Creek,

the adjacent San Antonio Terrace, and San

Antonio Lagoon are considered to be among

the most productive areas for red-legged

frogs in Santa Barbara County (Christopher

1996). Most of this area occurs on

Vandenberg Air Force Base. In this area,

California red-legged frogs are found in dune

swale ponds; this habitat type has remained

essentially undisturbed, and the conditions

seem to be less suitable for introduced fishes,

crayfish, and bullfrogs because they dry

completely in drought years. Jalama Lagoon

also supports a relatively large population of

the California red-legged frog (Christopher

1996).

The largest known populations in the northern

Transverse Range are on upper Alamo Creek

(a tributary to Cuyama River), a northern

tributary to the Sisquoc River, and La Brea

Creek and its southern tributary Manzana

Creek (S. Sweet in litt. 2000).

Populations of California red-legged frogs in

the lower Santa Ynez River Basin (Santa

Barbara County) are smaller and patchily

distributed. In this basin, deep pools with

dense marginal vegetation are rare and

introduced aquatic predators are abundant and

diverse (Christopher 1996). California redlegged frogs are also found in fairly high

numbers in the upper Santa Ynez River basin,

up to Lake Cachuma and its tributaries (S.

Christopher pers. comm. 1998); tributaries to

the Santa Ynez River (e.g., Salispuedes

Creek) also support California red-legged

frogs. The small coastal drainages between

Gaviota and Goleta also support California

red-legged frogs (M. Jennings et al. in litt.

1992, S. Christopher pers. comm. 1998, D.

Pereksta pers. comm. 1998) as do areas west

to Point Conception (P. Bloom in litt. 2000).

Drainages on the southern portion of the Los

Padres National Forest such as Upper Santa

Ynez, (in and above Jameson Reservoir),

Agua Caliente, Juncal, Indian, and Mono

Creeks still support California red-legged

frogs. They were depleted significantly from

the mainstem of Sespe Creek following a

1979-1981 bullfrog invasion. However, they

have persisted in low numbers in several of

the tributaries. The species is also in decline

in Piru Creek due to changes in flow regimes

since the construction of Pyramid Dam in
Recovery Plan for the California Red-legged Frog 11

Rangewide, and even within local

populations, there is much variation in

how frogs use their environment; in

some cases, they may complete their

entire life cycle in a particular

habitat....and in other cases, they may

seek multiple habitat types.

1973 and the introduction of many predatory

fish via the California aqueduct (P. Bloom in

litt. 2000). In the Santa Clara River

watershed, California red-legged frogs may

be found in the headwaters and tributaries of

the Santa Clara River (Jennings et al. in

litt.1992). To the east, in the Tehachapi

Mountains, historic records (mid-1800s) of

California red-legged frogs exist in Kern

County in El Paso Creek and near Fort Tejon.

In the 1980s, this species was observed in

Cedar Creek near Glennville and near the

Kern and San Luis Obispo County line (M.

Jennings et al. in litt. 1992).

Sweet and Leviton (1983 as cited in Jennings

1988a) reported the natural occurrence of the

California red-legged frog on Santa Cruz

Island (Santa Barbara County). According to

Jennings (1988a), it is likely that they were

introduced by Basque or French workers for

consumption. Based on recent reports, the

frogs still exist on Santa Cruz Island (M.

Jennings in litt. 1998b).

Southern Transverse Range and Peninsular

Ranges. The California red-legged frog was a

common native frog in parts of Los Angeles,

San Bernardino, Orange, Riverside, and San

Diego Counties (Jennings et al. in litt. 1992).

Numerous records of California red-legged

frogs exist from the 1930s, along the Mojave

River near Victorville (San Bernardino

County), as well as along the San Luis Rey

River in San Diego County. The frog

historically occurred in the San Gabriel

Wilderness Area of the Angeles National

Forest (Los Angeles County); until 1999,

there were no post-1970 observations in this

area or nearby parts of Angeles National

Forest (Jennings 1993). In 1999, a population

of California red-legged frogs was located on

the Angeles National Forest in the San

Francisquito drainage. Current population

estimates suggest that there are between 15

and 25 adults (R. Fischer pers. comm 2001).

However, this population is threatened by

non-native predators (bullfrogs, crayfish, and

non-native fish species), disease, and

parasites.

Until a recent sighting, California red-legged

frogs were considered to be extirpated from

the Santa Monica mountains (Los Angeles

County); the last record was from 1976 (M.

Jennings in litt. 1998a). A recent discovery of

California red-legged frogs was made in East

Las Virgenes Creek (Ventura County) in the

Simi Hills, adjacent to the Santa Monica

Mountains National Recreation Area. No

frogs were found in nearby streams (Las

Virgenes Creek, Palo Comado, Cheeseboro,

and Liberty canyons) (Sapphos

Environmental 1999). Current survey

information suggests that this breeding

population contains 20 to 25 adults, 10 to 15

juveniles, and several hundred tadpoles (R.

Smith in litt. 2001).

Today, in southern

California, south of

the Tehachapi

Mountains,

California red-legged

frogs are currently

known from only a

few locations,

compared to over 80

historic records from

this region. Former

populations in the

Whitewater River

canyon (Riverside

County), the eastern

San Bernadino

mountains, and

Sentenac Canyon in

the San Felipe Creek system of the Southern

Peninsular Ranges (San Diego County) have

not been observed since the 1960s (Jennings

and Hayes 1994). The existing locations

include Amargosa Creek near Palmdale (Los

Angeles County) and Cole Creek on The

Nature Conservancy’s Santa Rosa Plateau

Ecological Reserve (Riverside County).

Current survey data suggest that the effective

population size has been severely reduced

primarily due to predation by bullfrogs.

While this population contained greater than

10 breeding adults in the late 1980s to early

1990s, recent survey data suggests that only 2

males remain. This area is the focus of

augmentation and reestablishment project

being pioneered by the U.S. Fish and Wildlife

Service, the Los Angeles Zoo, The Nature

Conservancy, and the Mexican government.
12 Recovery Plan for the California Red-legged Frog

Overall, populations are most likely to

persist where multiple breeding areas

are embedded within a matrix of

habitats used for dispersal.

D. HABITAT

General Habitat. While nearly all of the

known California red-legged frog populations

have been documented below 1,050 meters

(3,500 feet), some historical sightings were

noted at elevations up to 1,500 meters (5,200

feet). Suitable habitat above 1,050 meters

(3,500 feet) may be more specific and may

include such requirements as: quiet water

refugia within 0.5

kilometers (0.25

miles) during high

water flows,

emergent vegetation

present on a

minimum of 25

percent of a pool or

pond margin, and

standing water that is

retained into late July

(S. Chubb in litt.

1999). Expanded

surveys will provide information necessary to

determine the elevational range limits of the

California red-legged frog.

California red-legged frogs live in a

Mediterranean climate, which is characterized

by temporal and spatial changes in habitat

quality. In addition to climatic fluctuations,

the habitats used by this species typically

change in extent and suitability in response to

the dynamic nature of floodplain and fluvial

processes (i.e., natural water flow and

sedimentation regimes that, in flux, create,

modify, and eliminate deep pools, backwater

areas, ponds, marshes, and other aquatic

habitats) (N. Scott and G. Rathbun in litt.

1998). Therefore, the frog uses a variety of

areas, including various aquatic, riparian, and

upland habitats (Figures 6, 7, 8, 9).

Rangewide, and even within local

populations, there is much variation in how

frogs use their environment; in some cases,

they may complete their entire life cycle in a

particular habitat (i.e., a pond is suitable for

all life stages), and in other cases, they may

seek multiple habitat types. Overall,

populations are most likely to persist where

multiple breeding areas are embedded within

a matrix of habitats used for dispersal (N.

Scott and G. Rathbun in litt. 1998). The

following descriptions describe the range of

habitat types used by the frog.

Breeding Habitat. Breeding sites of the

California red-legged frog are in a variety of

aquatic habitats; larvae, tadpoles, and

metamorphs have been collected from

streams, deep pools, backwaters within

streams and creeks, ponds, marshes, sag

ponds, dune ponds, and lagoons. Breeding

adults are often associated with deep (greater

than 0.7 meter [2 feet]) still or slow moving

water and dense, shrubby riparian or

emergent vegetation (Hayes and Jennings

1988), but frogs have been observed in

shallow sections of streams that are not

cloaked in riparian vegetation. Reis (1999)

found the greatest number of tadpoles

occurring in study plots with water depths of

0.26 to 0.5 meters (10 to 20 inches). While

frogs successfully breed in streams, high

flows and cold temperatures in streams

during the spring often make these sites risky

environments for eggs and tadpoles.

California red-legged frogs also frequently

breed in artificial impoundments such as

stock ponds. It is assumed, however, that

these ponds must have proper management of

hydroperiod, pond structure, vegetative cover,

and control of non-native predators, although

some stock ponds support frogs despite a lack

of emergent vegetation cover and the

presence of non-native predators (N. Scott

and G. Rathbun in litt. 1998). Additional

research on the habitat requirements of the

California red-legged frog in artificial ponds

may clarify this issue.

Dispersal and Use of Uplands and Riparian

Areas. During periods of wet weather,

starting with the first rains of fall, some

individuals may make overland excursions

through upland habitats. Most of these

overland movements occur at night. Evidence

from marked and radio-tagged frogs on the

San Luis Obispo County coast suggests that

frog movements, via upland habitats, of about

1.6 kilometers (1 mile) are possible over the

course of a wet season. Frogs have been

observed to make long-distance movements

that are straight-line, point to point migrations

rather than using corridors for moving in
Recovery Plan for the California Red-legged Frog 13

between habitats (N. Scott and G. Rathbun in

litt. 1998). Dispersing frogs in northern Santa

Cruz County traveled distances from 0.40

kilometer (0.25 mile) to more than 3

kilometers (2 miles) without apparent regard

to topography, vegetation type, or riparian

corridors (Bulger in litt.1998).

During dry periods, the California red-legged

frog is rarely encountered far from water

(Jennings et al. in litt. 1992). However,

California red-legged frogs will sometimes

disperse in response to receding water which

often occurs during the driest time of the year.

For example, between September 20 and

October 20 in 1999, 7 adults were observed

moving through nearby uplands on the

University of Santa Cruz campus as the

breeding pond dried (M. Allaback in litt.

2000).

The manner in which California red-legged

frogs use upland habitats is not well

understood; studies are currently examining

the amount of time California red-legged

frogs spend in upland habitats, patterns of

use, and whether there is differential use of

uplands by juveniles, subadults, and adults.

Dispersal distances are considered to be

dependent on habitat availability and

environmental conditions (N. Scott and G.

Rathbun in litt. 1998).

Frogs spend considerable time resting and

feeding in riparian

vegetation when it is

present. It is believed

that the moisture and

cover of the riparian

plant community

provide good

foraging habitat and

may facilitate

dispersal in addition

to providing pools

and backwater

aquatic areas for

breeding. California

Figure 6.

Aerial view of

breeding areas

surrounded by

upland dispersal

habitat.

Photo © Curt McCasland,

USFWS.

Frogs have been observed to make

long-distance movements that are

straight-line, point to point migrations

rather than using corridors for moving

in between habitats.
14 Recovery Plan for the California Red-legged Frog

Breeding sites of the CLRF are in a

variety of aquatic habitats:

 ◆ Stream

 ◆ Deep pools

 ◆ Backwater areas

 ◆ Ponds

 ◆ Marshes

 ◆ Sag ponds

 ◆ Dune ponds

 ◆ Lagoons

red-legged frogs can

be encountered

living within streams

at distances

exceeding 3

kilometers (2 miles)

from the breeding

site, and have been

found up to 30

meters (100 feet)

from water in

adjacent dense

riparian vegetation,

for up to 77 days

(Rathbun et al.

1993).

Summer Habitat.

California redlegged frogs often

disperse from their

breeding habitat to

forage and seek

summer habitat if water is not available. This

summer habitat could include spaces under

boulders or rocks and organic debris, such as

downed trees or logs; industrial debris; and

agricultural features, such as drains, watering

troughs, abandoned sheds, or hay-ricks.

California red-legged frogs use small

mammal burrows and moist leaf litter

(Jennings and Hayes 1994); incised stream

channels with portions narrower and deeper

than 46 centimeters (18 inches) may also

provide habitat (U.S. Fish and Wildlife

Service 1996a). This depth may no longer be

an accurate estimate of preferred depth for

this species as individuals have been found

using channels and pools of various depths.

Most observations are associated with depths

greater than 25 cm (10 inches). For example,

M. Allaback (in litt. 2000) has observed

numerous red-legged frogs inhabiting stream

channels with pools that are less than 46

centimeters (18 inches) deep, particularly in

north coastal Santa Cruz County and

generally from late spring to the fall. Some of

the observations have been along tributaries

where there are no pools that are 46 centimeters (18 inches deep) for several thousand

feet. At one site, along a tributary to Liddell

Figure 8. Breeding

pool and streamside

vegetation in Round

Valley Creek, Contra

Costa County.

Photo © Steven Bobzien

Figure 7.

Breeding habitat in

Ledson Marsh,

Sonoma County.

Photo © David Cook
Recovery Plan for the California Red-legged Frog 15

Creek (Santa Cruz County), the same individuals were seen at the same streamside locations for several weeks in late summer during

a monitoring project. Pool depth averaged

approximately 30 centimeters (12 inches). In

2000, an adult red-legged frog was observed

in shallow, 5 centimeter (2 inch) deep riffle

habitat in a disturbed drainage in lower Little

Bull Valley (Contra Costa County). Here, no

pool or pond habitat was present within

approximately 300 meters (1,000 feet).

California red-legged frogs use large cracks

in the bottom of dried ponds as refugia.

Approximately 25 red-legged frogs were

observed using open cracks in the bottom of

three separate dried ponds. At least one pond

was dry for more than 2 months when adult

frogs were found deep in the cracks of the

pond bottom. Many cracks within which

frogs were found were damp at a depth of 46

centimeters (18 inches). These cracks may

have provided moisture for frogs that were

also avoiding predation and solar exposure (J.

Alvarez in litt. 2000). Dispersal and habitat

use, however, is not observed in all studied

red-legged frogs and is most likely dependent

upon climatic conditions, habitat suitability,

and varying requisites of each life stage.

Water Quality. California red-legged frogs

are sensitive to high salinity, which often

occurs in coastal lagoon habitats. When eggs

are exposed to salinity levels greater than 4.5

parts per thousand, 100 percent mortality

occurs (Jennings and Hayes 1990). Larvae die

when exposed to salinity levels greater than

7.0 parts per thousand (M. Jennings in litt.

1993). Reis (1999) found that the proportion

of study plots without tadpoles was greatest

among plots with salinity levels greater than

6.6 parts per thousand.

Early embryos of northern red-legged frogs

are tolerant of temperatures only between 9

and 21 degrees Celsius (48 and 70 degrees

Fahrenheit) (Nussbaum et al. 1983). Study

plots at Pescadero Marsh (San Mateo County)

with the greatest number of California redlegged frog tadpoles had mean water

temperatures between 15.0 and 24.9 degrees

Celsius (60 to 75 degrees Fahrenheit).

Observations by S. Bobzien (pers.comm.

Figure 9. Dune swale

breeding pond on

Vandenberg Air

Force Base, Santa

Barbara County

(top).

Photo © Ina Pisani

Breeding habitat in a

stockpond on Ohlone

Regional Wilderness,

Alameda County

(bottom).

Photo © Steven Bobzien

1998) indicated that California red-legged

frogs were absent when temperatures exceed

22 degrees Celsius (70 degrees Fahrenheit),

particularly when the temperature throughout

a pool was this high and there are no cool,

deep portions.

E. LIFE HISTORY AND ECOLOGY

Reproduction. California red-legged frogs

breed from November through April (Storer

1925). Males appear at breeding sites from 2

to 4 weeks before females (Storer 1925). At

these sites, males frequently call in small

groups of two to seven individuals, although

in some instances they may call individually

(Jennings et al. in litt. 1992). Females are

attracted to the calling males. A pair in
16 Recovery Plan for the California Red-legged Frog

amplexus (breeding position) moves to an

oviposition site (the location where eggs are

laid) and the eggs are fertilized while being

attached to a brace. Braces include emergent

vegetation such as bulrushes (Scirpus spp.)

and cattails (Typha spp.) or roots and twigs;

the egg masses float on the surface of the

water (Hayes and Miyamoto 1984). Each

mass contains about 2,000 to 5,000 eggs that

are each about 2.0 to 2.8 millimeter (0.08 to

0.11 inches) in diameter (Figure 8). The eggs

are dark reddish brown (Storer 1925).

Growth and Development. Eggs hatch in 6 to

14 days depending on water temperatures

(Jennings 1988b). Egg predation is infrequent

and most mortality probably occurs during

the tadpole stage (Licht 1974), although eggs

are susceptible to being washed away by high

stream flows. Schmeider and Nauman (1994)

report that California red-legged frog eggs

have a defense against predation which is

possibly related to the physical nature of the

egg mass jelly, although Rathbun (1998) has

documented newt predation on eggs and

suggested that this predation may be an

important factor in the population dynamics

of the California red-legged frog.

Typically, most adult frogs lay their eggs in

March. Eggs require approximately 20-22

days to develop into tadpoles, and tadpoles

require 11 to 20 weeks to develop into

terrestrial frogs. (Bobzien et. al. 2000, Storer

1925, Wright and Wright 1949). Several

researchers, however, have observed

overwintering tadpoles (i.e., tadpoles that did

not metamorphose within their first breeding

season) in recent surveys. In Round Valley

Creek (Contra Costa County) on East Bay

Regional Park District land, overwintering

tadpoles were documented in 1997, 1998,

1999, and 2000. In these cases, metamorphs

were observed in March and April from

previous breeding seasons. These frogs were

relatively small in size and still had posterior

scar tissue where their tails were located.

Further, numerous tadpoles were seen in late

fall (October and November) and several in

December and January. The majority of these

individuals had rudimentary or developed

hind limbs and appeared to have

overwintered in this stage. (Bobzien et al.

2000).

Sexual maturity can be attained at 2 years of

age by males and 3 years of age by females

(Jennings and Hayes 1985); adults may live 8

to 10 years (Jennings et al. in litt. 1992),

although the average life span is probably

much lower (N. Scott pers. comm. 1998).

Schmieder and Nauman (1994) reported that

California red-legged frog larvae are highly

vulnerable to fish predation, especially

immediately after hatching, when the

nonfeeding larvae are relatively immobile.

Activity Patterns and Movements. Hayes and

Tennant (1985) found juvenile frogs to be

active diurnally and nocturnally, whereas

adult frogs were largely nocturnal. The

season of activity for the California redlegged frog seems to vary with the local

climate (Storer 1925); individuals from

coastal populations, which rarely experience

low temperature extremes because of the

moderating maritime effect, are rarely

inactive. Individuals from inland sites, where

temperatures are lower, may become inactive

for long intervals (Jennings et al. in litt. 1992)

and no information is available on the activity

levels of California red-legged frogs at higher

elevations.

Feeding. The diet of California red-legged

frogs is highly variable. The foraging ecology

of larvae has not been studied, but they are

thought to be algal grazers (Jennings et al. in

litt. 1992). Hayes and Tennant (1985) found

invertebrates to be the most common food

items of adult frogs. Vertebrates, such as

Pacific tree frogs (Hyla regilla) and

California mice (Peromyscus californicus),

represented over half of the prey mass eaten

by larger frogs, although invertebrates were

the most numerous food items. Feeding

typically occurs along the shoreline and on

the surface of the water; juveniles appear to

forage during both daytime and nighttime,

whereas subadults and adults appear to feed

at night (Hayes and Tennant 1985). Radiotracking studies suggest that frogs also forage

several meters into dense riparian areas (G.

Rathbun pers. comm 1993, as cited in U.S.

Fish and Wildlife Service 1996a).
Recovery Plan for the California Red-legged Frog 17

F. REASONS FOR DECLINE AND THREATS TO

SURVIVAL

The California red-legged frog is threatened

by human activities, many of which operate

synergistically and cumulatively with each

other and with natural disturbances (i.e.,

droughts or floods). Factors associated with

declining populations of the frog include

degradation and loss of its habitat through

agriculture, urbanization, mining,

overgrazing, recreation, timber harvesting,

non-native plants, impoundments, water

diversions, degraded water quality, use of

pesticides, and introduced predators. The

reason for decline and degree of threats vary

by geographic location. California red-legged

frog populations are threatened by more than

one factor in most streams. The following

discussion is organized according to the five

listing criteria under section 4(a)(1) of the

Endangered Species Act.

1. The Present or Threatened Destruction,

Modification, or Curtailment of Habitat or

Range.

Curtailment of Range and Alteration,

Fragmentation, Degradation, and Loss of

Habitat. Habitat loss and alteration are the

primary factors that have affected the

California red-legged frog negatively

throughout its range. For example, in the

Central Valley of California, over 90 percent

of historic wetlands have been diked, drained,

or filled for agricultural and urban

development (U.S. Fish and Wildlife Service

1978, Dahl 1990). This has resulted in a large

loss of frog habitat throughout this species’

range.

California red-legged frog habitat has become

isolated and fragmented along many stream

courses. Patches of suitable habitat represent

remnants of a much larger historical habitat,

which once covered entire drainages. With

habitat fragmentation, dispersal opportunities

are reduced and interactions between subpopulations can be precluded, jeopardizing

the viability of metapopulations. Isolated

populations are vulnerable to extinction

through random adverse environmental

events and human-caused impacts (Soulé

1987). Further, dispersal between fragments

exposes frogs to increased risk of predation

(G. Rathbun in litt. 1998).

In addition to the isolation of populations, the

range of the California red-legged frog has

been severely reduced. While numerous

localities exist along the Pacific coast from

Point Reyes south through Santa Barbara

County, few localities exist in the Sierras and

southern California.

Urbanization. Current and future

urbanization poses a significant threat to the

California red-legged frog. In 1995,

approximately 27 percent of the known

occurrences were associated with

urbanization threats and many areas within

the range of the frog were slated for

development (U.S. Fish and Wildlife Service

1996a). Urban and suburban developments

often leave isolated habitat fragments and

create barriers to frog dispersal. Numerous

studies, as discussed below, have

demonstrated the impacts of fragmentation on

other frog and toad species. Urban

populations of common frogs (Rana

temporaria) were more genetically distinct

than rural populations (Hitchings and Beebee

1997). Based on genetic analysis, Reh and

Seitz (1990) found that highways effectively

isolated common frog populations. Kuhn

(1987, in Reh and Seitz 1990) estimated that

24 to 40 cars per hour killed 50 percent of

common toad (Bufo bufo) individuals

migrating across a road, while Heine (1987,

in Reh and Seitz 1990) found that 26 cars per

hour could reduce the survival rate of toads

crossing roads to zero. Fahrig et al. (1995)

found a significant negative correlation

between traffic density and the density of

anuran (frog and toad) populations. Thus,

roads are an important human-caused

landscape component hindering amphibian

movement and thereby fragmenting

amphibian populations.

Because urbanization typically results in

additional water sources into wetlands and

stream courses, due to irrigation and home

use activities, another consequence of

urbanization is the change in hydroperiod of

historically ephemeral drainages to perennial
18 Recovery Plan for the California Red-legged Frog

streams (often due to wastewater outflows).

This change allows the proliferation of nonnative predators (M. Moore and M. Westphal

in litt. 1997). Richter and Azous (1997)

observed wetlands adjacent to undeveloped

upland areas were more likely to have richer

populations of native amphibians. The

reduced richness of amphibians in wetlands

with highly urbanized watersheds is likely

due, in part, in part, to differences in

hydrologic patterns related to land use.

In addition to the modification of

hydroperiod, development within the

watershed can also affect water and habitat

quality. As watersheds are developed, the

amount of impervious surface increases,

resulting in an increase of sediments

containing organic matter, pesticides, and

fertilizers, heavy metals such as

hydrocarbons, and other debris into streams

and wetlands (Environmental Protection

Agency 1993). Skinner et al. (1999) found

developed watersheds had greater

concentrations of toxic effluents than less

developed areas with more open space. The

decrease in water quality can have profound

impacts on native amphibians and other

wetland vertebrates. Other consequences

include channelization of creeks (which

reduces or eliminates breeding sites) and

increased suitability for predators such as

non-native fish, bullfrogs, and raccoons, all of

which thrive in disturbed conditions (Harris

1998).

Agriculture. Agricultural practices pose a

threat to the California red-legged frog

populations due to loss or modification of

frog habitats. Many crops (e.g., row crops)

are stands of monotypic vegetation, which

replace varied natural habitats. Fisher and

Shaffer (1996) studied historic records and

conducted surveys for amphibians in the

Sacramento Valley, San Joaquin Valley, and

Coast range. In the San Joaquin Valley,

drastic declines of both native and non-native

amphibians were noted. The authors suggest

that the declines may be due to intense

farming rendering the few remaining ponds

and pools on the valley floor uninhabitable

even for introduced species. Agricultural

practices typically include the use of

fertilizers and pesticides including herbicides

and fungicides, that may pose contamination

threats to the frog. Impacts include

deformities, abnormal immune system

functions, diseases, injury, and death (see

Appendix B) (K. Woodburn in litt. 1996,

Schneeweiss and Schneeweiss 1997). An

important factor in the decline of the

California red-legged frog may be exposure

to wind-borne agrochemicals. A number of

studies have documented transport and

deposition of pesticides from the Central

Valley to the Sierra Nevada mountain range

(Zabik and Seiber, 1993, Aston and Seiber

1997, Datta 1997, McConnell et al 1998 as

cited in Davidson et al. 2001). There is a

strong relationship between increasing levels

of upwind agriculture and the percentage of

extirpated California red-legged frog

population sites; this relationship is

particularly pronounced within the Sierra

Nevada-Central Valley region where

agriculture is the greatest (Davidson et al.

2001). In this region, the percentage of

upwind land in agriculture for sites where the

California red-legged frog has disappeared is

6.5 times greater than for sites where they

persist (Davidson et al. 2001). Similarly,

Sparling et al. (2001) noted that the most

severe declines of amphibians, including

California red-legged frogs, are in the Sierra

Nevada mountains east of the central valley

and downwind of the intensely agricultural

San Joaquin valley. In contrast, coastal and

more northern populations across from the

less agrarian Sacramento valley are stable or

declining less precipitously.

Water diversion and impoundment for

irrigation, can reduce the flows necessary to

support adequate aquatic habitat for frogs and

other species. The California coast supports

several agricultural activities including

artichoke production, flower nurseries, and

other irrigated crops that require the use of

irrigation ponds. Water is collected during the

winter months from rainfall and is also

pumped out of coastal drainages into ponds.

These ponds typically grow shoreline

vegetation such as cattails, tules (Scirpus

spp.), and horsetails (Equisetum spp.), and

with proper water management can provide

high quality breeding habitat. However,
Recovery Plan for the California Red-legged Frog 19

farmers often start irrigating crops during the

late spring, and continue through summer. As

water is drawn down, egg masses can be

exposed and desiccate. Although the outlets

may be screened, the pumps used are

powerful enough to suck tadpoles and

juveniles against the screen and can crush

individuals. Depending upon their size, ponds

also may be drawn down to such an extent

that they completely dry out or are shallow

enough to allow significant predation of frogs

(particularly tadpoles that have not fully

metamorphosed) by waterbirds. Ponds that

are not drawn down all the way often support

predatory sunfish (Lepomis spp.), largemouth

bass (Micropterus spp.), and bullfrogs (S.

Larsen in litt. 1998). Some agricultural

activities (e.g., nurseries) provide a large

flush of pesticides into stream systems during

rain events and may pose a threat to frogs (C.

McCasland in litt. 1998b). The effects of

agricultural activities are especially intense in

the Central Valley, Salinas Valley, the coastal

plain of Monterey County, and parts of San

Luis Obispo and Santa Barbara Counties.

Impoundments and Water Management. In

the Central Valley and surrounding foothills

the construction and filling of large

reservoirs, which are typically situated at or

just below the juncture of several tributaries,

either directly eliminated, fragmented, or

isolated populations of the California redlegged frog. Examples include the

construction of Lake Oroville (Butte County),

Whiskeytown Reservoir (Shasta County),

Folsom Reservoir (Placer, El Dorado

Counties), Lake Berryessa (Napa County),

and San Luis Reservoir (Merced County)

within the Central Valley hydrologic basin

(Jennings et al. in litt. 1992). At least 40

percent of the historically suitable California

red-legged frog habitat on the Los Padres

National Forest has been fragmented by the

placement of dams on streams. The major

existing dams include San Clemente and Los

Padres Dams on the Carmel River; Twitchell

Dam and Reservoir on the Cuyama and

Alamo watersheds; Bradbury, Gibraltar, and

Juncal Dams on the Santa Ynez River;

Matilija Dam on Matilija Creek; and Santa

Felicia and Pyramid Dams on Piru Creek (S.

Chubb in litt. 1998).

Lind et al. (1996) studied the effects of a dam

on the foothill yellow-legged frog (Rana

boylii) in the Trinity River (Trinity County).

Unlike the California red-legged frog, this

species is typically associated with stream

riffles. Here, dams reduced breeding habitat

due to changes in channel morphology and

eliminated entire cohorts due to unseasonable

high flow releases. Other dam-related factors

that may have influenced the breeding

ecology of the foothill yellow-legged frog are

water temperature, exotic species, and

changes in prey base. Hayes and Jennings

(1988) found that California red-legged frogs

generally were extirpated from downstream

portions of a drainage 1 to 5 years after filling

of a reservoir, depending on the size of the

drainage. However, in some larger drainages,

isolated populations have been observed to

persist upstream of a reservoir.

Some populations of frogs are known to use

reservoirs at least in the adult stage (e.g.,

Jamieson Reservoir on the Santa Ynez River).

On Los Padres National Forest, plunge pools

and seepage pools that occur at the base of

most dams are prime California red-legged

frog habitat, and viable populations have

persisted despite dams (S. Chubb in litt.

1999). It is not clear if these reservoirs are a

source or sink to the overall California redlegged frog population in these areas; the

suitability may depend on the presence of

non-native species and/or other land-use

disturbances such as recreation. Reservoirs

are typically stocked with non-native

predatory fishes. Bullfrogs were stocked in

the past and continue to spread. These species

often disperse upstream and downstream into

California red-legged frog habitat and disrupt

natural community dynamics.

Many small impoundments are situated on

private and public lands. For example, on Los

Padres National Forest, there are 150 small

impoundments, over 500 small water

diversions exist, and approximately 190

springs are diverted. Most of these diversions

and impoundments are operated as temporary

storage of surface water run-off in ephemeral

drainages for livestock and/or wildlife

watering. Impoundments can structurally

block or hinder dispersal. Further, they can
20 Recovery Plan for the California Red-legged Frog

eliminate the high flows needed to maintain

moderately deep holes in stream channels (G.

Rathbun in litt. 1998). Stock ponds and small

reservoirs also typically support populations

of non-native fishes and bullfrogs (G.

Rathbun and M. Jennings in litt. 1993). In

contrast, California red-legged frogs

frequently use small reservoirs as breeding

habitat, and these sites may be good

producers of California red-legged frogs with

the proper management of water and nonnative predators.

Channelization and Flood Control. Routine

flood control maintenance, which typically

includes vegetation removal, herbicide

spraying, shaping and riprapping of banks to

control erosion, and dredging of creeks and

rivers, can result in degradation of California

red-legged frog habitat. Widespread

channelization of watercourses for flood

control and water diversion has eliminated

habitat along small to medium-sized

watercourses (Harding 1960), and has

allowed the proliferation of non-native

aquatic species. Management of water flows

for flood control also has the potential to

adversely impact California red-legged frogs.

For example, in San Mateo County, poorly

timed releases of storm water flows from

Horse Stable Pond at Sharp Park in February

1992, resulted in exposure and desiccation of

62 California red-legged frog egg masses (T.

Steiner in litt. 1994).

Mining. Suction dredge mining may threaten

California red-legged frog habitat. Jennings et

al. (in litt. 1992) reported heavy siltation in

late spring and summer in portions of Piru

Creek (Santa Barbara County), which is

known to support California red-legged frogs.

The siltation resulted from upstream gold

mining. Extremely deep holes in streams

created by instream suction dredge mining

may also provide habitat for non-native

predatory fish (U.S. Fish and Wildlife Service

1996a). Creeks, streams, and rivers are open

to suction dredging throughout the year in

many counties within the range of the

California red-legged frog.

Sand and gravel mining practices can alter

natural channel morphology in downstream

reaches by interrupting the supply of sand and

gravel, which is needed for localized shallow,

braided channels (Collins and Dunne 1990).

Long-term gravel mining on point bars

retards the development of appropriate soil

conditions for riparian vegetation. Continued

instream gravel mining activities without

adequate safeguards may preclude favorable

habitat conditions for the California redlegged frog. California red-legged frogs have

colonized active and inactive sediment basins

at two quarries in Santa Cruz County (Bonny

Doon Quarry and Wilder Ranch Quarry) and

it is possible that frogs inhabit other sediment

basins associated with quarries throughout the

species’ range (M. Allaback in litt. 2000).

Effluent from mercury mines has created high

levels of mercury in the upper Nacimiento

River basin (Salinas River drainage), and

probably other streams in the Santa Lucia

Mountains (N. Scott in litt. 1998).

Within Los Padres National Forest, oil and

gas development occupies approximately 73

hectares (200 acres) within Sespe and Hopper

creeks. There has been one documented oil

spill which extended 3 kilometers (2 miles)

down Sespe Creek. Los Padres National

Forest has since worked with the lessees to

establish and implement Best Management

Practices and properly cap old wells and

remove storage tanks. Oil and gas pipelines

also extend across a number of drainages

within San Luis Obispo, Santa Barbara, and

Ventura Counties. There is always a risk of

leakage or breakage near stream crossings (S.

Chubb in litt. 1999).

Livestock Grazing and Dairy Farming.

Livestock grazing is another form of habitat

alteration that may be both (1) contributing to

declines in the California red-legged frog by

decreasing suitability of riparian and aquatic

habitat and (2) in many instances, providing

frog habitats.

In many cases, California red-legged frogs

co-exist with managed livestock grazing.

High numbers of frogs are found in areas

such as Point Reyes National Seashore, many

East Bay Regional Parks, and private land

holdings where stock ponds and cattle are

prevalent. In many of these areas, California
Recovery Plan for the California Red-legged Frog 21

Livestock grazing is another form of

habitat alteration that may be both

contributing to declines of the

California red-legged frog by

decreasing suitability of riparian and

aquatic habitat and, in many

instances, providing frog habitats.

red-legged frogs may be present only because

livestock operators have artificially created

ponds for livestock water where there were

none before and therefore, created frog

habitats. In such ponded habitat, grazing may

help maintain habitat suitability by keeping

ponds clear where they might otherwise fill in

with cattails, bulrushes, and other emergent

vegetation (S. Bobzien in litt. 1998, G. Fellers

in litt. 1998, N. Scott and G. Rathbun in litt.

1998).

In other areas, however, observations suggest

that grazing activities pose a serious threat to

the suitability of aquatic habitats for

California red-legged frogs. For example,

exclusion of cattle grazing from the Simas

Valley (Contra Costa County) resulted in

reestablishment of native trees and native

wetland herbs, re-establishment of creek

pools, and expansion of frog populations into

streams and ungrazed stock ponds (Dunne

1995). Further research is necessary to

determine the role of drought and population

size in this observed expansion of red-legged

frogs into streams, because the exclusion of

cattle coincided with the end of a prolonged

drought. Other biologists have noted that

when cattle drink from small ponds and

streams they can draw down water levels,

leaving egg masses above the water level and

subjecting them to desiccation and/or disease

(e.g., fungal infections) (S. Chubb in litt.

1998). Grazing cattle can also cause direct

impacts to frogs by crushing and/or

disturbing egg masses (S. Chubb in litt.

1998), larvae, and metamorphosing frogs.

Numerous studies, summarized by Behnke

and Raleigh (1978) and Kauffman and

Krueger (1984), have shown that livestock

grazing can negatively affect riparian habitat,

marshes, and ponds. Cattle have an adverse

effect on riparian and other wetland habitats

because they tend to concentrate in these

areas, particularly during the dry season

(Marlow and Pogacnik 1985). Poorly

managed grazing in riparian areas often

results in downcutting and loss of plunge

ponds, which in turn, decreases pool habitats

for California red-legged frogs. The

consequences of these changes in riparian

conditions and the effect on the frog are

largely unknown.

Unmanaged cattle trample and eat emergent

and riparian vegetation, often eliminating or

severely reducing plant cover (Gunderson

1968, Duff 1979). Loss of riparian vegetation

results in increased water temperatures (Van

Velson 1979), which

decreases suitability

for California redlegged frogs and

encourages

reproduction of

bullfrog and nonnative warm water

fishes. Effects on

riparian vegetation

due to cattle grazing

include the loss of

willows (Duff 1979),

which are associated

with the highest

densities of

California red-legged

frogs (Hayes and

Jennings 1988,

Jennings 1988b).

Loss of streamside vegetation also reduces

habitat for insects and small mammals, which

are important dietary components for aquatic

and riparian associated species, including the

red-legged frog (Cordone and Kelley 1961).

Cattle overgrazing also results in increased

erosion in the watershed (Lusby 1970,

Winegar 1977), which accelerates the

sedimentation of deep pools (Gunderson

1968) used by California red-legged frogs.

High levels of sediment introduced into

streams can alter primary productivity and fill

interstitial spaces in streambed materials with

fine particulates, which impede water flow,

reduce dissolved oxygen levels, and restrict

waste removal (Chapman 1988). The

populations of California red-legged frogs in

the Corral Hollow Ecological Reserve and

Frank Raines Regional Park are threatened, in

part, by sedimentation of aquatic habitats

either directly or indirectly caused by grazing

(M. Jennings et al. in litt. 1992). Livestock

grazing can cause a nutrient loading problem

due to urination and defecation in areas where

cattle are concentrated near the water (Doran

et al. 1981). The primary contaminant in the

tributaries to Tomales Bay (Marin County) is
22 Recovery Plan for the California Red-legged Frog

waste from cattle ranches and dairies (San

Francisco Chronicle 1998).

Overall, grazing may both enhance California

red-legged frog populations and be a

detriment to habitat suitability; the effects

probably depend on the grazing practices,

watershed integrity, and conditions of a

particular site. For example, the East Bay

Regional Park District uses livestock grazing

for vegetation management and habitat

enhancement. The vast majority of California

red-legged frogs observed on Park District

lands are in artificial ponds or in streams that

are exposed to livestock grazing (Bobzien et

al. 2000). While safeguards may be needed to

protect riparian and aquatic habitats, with

proper management of artificial ponds and

appropriate grazing regimes, this land use

may prove to be a benefit to this species as

witnessed in Alameda, Contra Costa, Marin,

Sonoma, Santa Cruz, and San Luis Obispo

Counties (N. Scott in litt. 1999).

Recreation and Off-Road Vehicles. Routine

road maintenance, trail development, and

facilities construction associated with parks

and other public lands, in or adjacent to

California red-legged frog habitat can

degrade habitat quality (U.S. Fish and

Wildlife Service 1996a). Heavy recreational

use of parks (e.g., fishing, hiking, use of

developed sites, dispersed camping) can also

degrade habitat for the California red-legged

frog. People tend to congregate around

aquatic areas and can trample vegetation,

trample frog eggs and young, increase noise

levels, and change the environment. At Big

Basin Redwoods State Park in Santa Cruz

County, heavy recreational use may have

contributed to the disappearance of California

red-legged frogs from Opal Creek (U.S. Fish

and Wildlife Service 1996a).

Unmanaged off-road vehicles can damage

riparian vegetation, increase siltation in pools,

compact soils, disturb the water in stream

channels, and crush frogs. California redlegged frogs were eliminated, in part by offroad vehicle activities, at the Mojave River

above Victorville, and at Rincon Station on

the West Fork of the San Gabriel River (U.S.

Fish and Wildlife Service 1996a).

Mountain bikes may also pose a threat to

California red-legged frogs. Wilder Ranch

(Santa Cruz County) is used by a high

number of mountain bikers daily. In 1996, a

sub-adult red-legged frog was observed on a

bike trail along Baldwin Creek. Where bike

paths are regularly used at night on the

University of California Santa Cruz campus,

there have been reported deaths of California

red-legged frogs due to bike strike (M.

Allaback in litt. 2000).

Recreational activities such as angling often

result in the introduction of non-native

species either through the artificial stocking

of streams, lakes, and ponds or the use of

non-native species as bait. These non-native

species, such as bass and sunfish, can prey

upon and ultimately eliminate native species.

Mechanical disturbances of habitats, such as

trampling of vegetation, can increase the

proliferation of non-native vegetation.

Littering associated with recreational

activities can also introduce toxic substances

such as motor oil, antifreeze, and other

substances or items that are harmful to the

aquatic and riparian community (S. Chubb in

litt. 1998).

Timber Harvesting. Timber operations and

related practices occurring on commercial,

private, and public timberlands within

watersheds inhabited by the California redlegged frog may contribute to the degradation

of instream and riparian habitat and the

decline of California red-legged frog and

other aquatic species. The effects that degrade

habitat include increased sedimentation of

gravels and pools, removal of trees that

provide instream and streamside habitat

structure and shade, and changed patterns of

runoff (U.S. Fish and Wildlife Service 1996a,

1996b). Access roads, haul roads, skid trails,

and ground based (tractor) yarding systems

have great impacts related to sedimentation

and compaction. Wet weather operations also

have more potential for impacts. Timber

harvesting in upland habitat can also impact

California red-legged frogs by causing direct

harm or injury to frogs that may be dispersing

or sheltering.

Within the current range of the California red-
Recovery Plan for the California Red-legged Frog 23

legged frog, timber harvest activities are most

likely to occur in the following areas: (1) the

Sierra Nevada foothills; (2) along the coast in

Santa Cruz County; and (3) in certain

watersheds in Sonoma, Napa, and Lake

Counties. Timber harvest activities occur in

many areas within the California red-legged

frog’s historic range, but outside the known

current range. These areas include Glenn,

Tehama, Shasta, Lassen, and Plumas

Counties, and the counties on the west slope

of the Sierra Nevada south to Tulare County.

South of Santa Cruz County, the majority of

timber harvest activities relate to fuelwood

gathering, and pose a minimal threat to

watersheds (S. Chubb in litt. 1999) although

this practice may remove cover and refugia

that frogs may rely upon.

2. Overutilization for Commercial,

Recreational, Scientific, or Education

Purposes

Exploitation. Exploitation of California redlegged frogs for food began during the period

following the gold rush of 1849 (Jennings and

Hayes 1984, 1985). By the mid-1870s, it was

recognized that their numbers were

diminishing in the vicinity of San Francisco

(Lockington 1879). Overharvest, driven by a

significant commercial demand, was

indicated by a sharp reduction in frog harvest

size in the late 1880s, and by the attempt to

compensate for depleted wild stocks of the

California red-legged frog, by introducing

bullfrogs (Jennings and Hayes 1984, 1985).

Commercial exploitation reduced lowland

populations, particularly those on the floor of

the Central Valley, to low levels (Jennings

1988b). This past exploitation is not a factor

that is causing current declines, as commercial harvesting of California red-legged frogs

has not occurred for a number of years.

Scientific Take. Qualified individuals may

obtain permits to conduct scientific research

activities on California red-legged frogs

under section 10(a)(1)(A) of the Endangered

Species Act. Specific activities that may be

authorized include: capturing, handling,

weighing, measuring, radiotracking studies,

genetic studies, contaminant studies, and

behavioral, ecological, and life history

studies. Short term impacts of these activities

may include harassment and possible

accidental injury or death of a limited number

of individual frogs. The long-term impacts

will be to benefit recovery of the species by

facilitating development of more precise

scientific information on status, life history,

and ecology.

3. Disease and Predation

Disease. Pathogens and parasites have been

implicated in the decline of other frog

species, but there has not been an extensive

examination of how disease may adversely

affect California red-legged frog populations.

Currently, the San Francisquito drainage

population in Los Angeles County is being

monitored for disease and parasites which are

the suspected cause of this population’s

decline (R. Fischer pers. comm 2001). It has

been suggested that increased levels of UV-B

radiation or air pollutants cause a weakening

of the immune system which could increase

the susceptibility of frogs to natural diseases

(Blaustein and Wake 1995, P. Montague in

litt. 1998). Another hypothesis, supported by

observations, is that disease carried by

planted trout may attack and kill amphibian

eggs and larvae (Blaustein et al. 1994).

Lefcort and Blaustein (1995) documented the

effects of the yeast Candida humicola, which

is a naturally occurring pathogen, on northern

red-legged frogs. Infected frogs were more

susceptible to predation due to changes in

their ability to detect predators and changes in

their thermoregulatory behavior. Little

information exists concerning the distribution

of this pathogen. A high incidence of

parasites has been observed in bullfrogs that

coexist with California red-legged frogs (>90

percent of sampled population with evidence

of infection) in southern California. Data

have not yet been collected to determine if

California red-legged frogs are also

contaminated in these areas; however, adult

red-legged frogs appear to be in poor

condition with low body weight.

Chytrid fungus has been found in a number of

amphibian populations that are known to be

declining. Signs of amphibian

chytridiomycosis include deformed
24 Recovery Plan for the California Red-legged Frog

mouthparts in tadpoles; most individuals that

are infected as tadpoles die when they

metamorphose. Infected boreal toads (Bufo

boreas boreas) found in Rocky Mountain

National Park, Colorado, showed few clinical

signs of the disease but many appeared weak

or lethargic, exhibited excessive shedding of

skin and were reluctant to flee at the approach

of humans (U.S. Geological Service 2000).

Chytrids are widespread in the environment

where they act as decomposers of keratin,

chitin, cellulose, and other plant material.

Chytrids are also known parasites of fungi,

algae, higher plants, protozoa, and

invertebrates, but none were known to infect

vertebrates until recently. Chytrid fungi

reproduce asexually by means of minute,

fragile, motile spores, and are probably

spread directly from amphibian to amphibian

in water. Chytrids probably move from one

water source to another on migrating

amphibian, or on waterbirds or flying insects

(Daszak et al. 1999).

Chytrid fungus in amphibians was first

identified in 1998 by an international team of

scientists from Australia, the United States,

and Great Britain. This team discovered that

the fungus had most likely been responsible

for large amphibian die-offs in pristine areas

of Panama and Australia. It also was a factor

and probable cause of recent die-offs in

remaining populations of the endangered

boreal toad (Bufo boreas boreas) in the

southern Rocky Mountains. Dead and dying

Chiricahua leopard frogs (Rana

chiricahuensis) at study sites in Arizona were

diagnosed with a chytrid fungal skin infection

(Colorado Herpetological Society 2000).

Here, entire populations have been lost or

reduced to very low numbers by an outbreak

of chytrid fungus. Furthermore, two

amphibian species in the Sierra Nevada (i.e.,

mountain yellow-legged frog (Rana muscosa)

and the Yosemite toad (Bufo canoris)) have

been observed to be infected by a chytrid

fungus (G. Fellers pers. comm. 1999). A

California red-legged frog tadpole was

collected with a chytrid fungus infection in

Calabasas Pond on the Ellicott Slough

National Wildlife Refuge in Santa Cruz

County (G. McLaughlin in litt. 2000). While

it is not yet clear what role the fungus plays

in the decline of California red-legged frogs,

it is appropriate to take some precautions

against spreading fungus between sites (U.S.

Geological Survey 2000). The disease is now

being studied in detail to understand its

origin, incidence, distribution and control

methods.

Predation by Introduced Species. Introduced

bullfrogs, crayfish, and species of fish have

been a significant factor in the decline of the

California red-legged frog. All of these

species were introduced into California in the

late 1800s and early 1900s, and through range

expansions and transplants have become

established throughout most of the State

(Riegel 1959, Bury and Luckenbach 1976,

Moyle 1976). Introduced aquatic vertebrates

and invertebrates are predators on one or

more of the life stages of California redlegged frogs. These include bullfrogs, African

clawed frogs (Xenopus laevis), red swamp

crayfish (Procambarus clarkii), signal

crayfish (Pacifastacus leniusculus), and

various species of fishes, especially bass,

catfish (Ictalurus spp.), sunfish, and

mosquitofish (Gambusia affinis) (Hayes and

Jennings 1986).

Several researchers in central California have

noted the decline and eventual disappearance

of California red-legged frogs once bullfrogs

become established at the same site (Moyle

1976, S. Barry in litt. 1992, L. Hunt in litt.

1993, Fisher and Schaffer 1996). Changes in

habitat that are unfavorable to California redlegged frogs tend to be favorable to a suite of

introduced non-native aquatic predators, making it difficult to identify detrimental effects

of specific introduced species on California

red-legged frogs. Bullfrogs prey on California

red-legged frogs (Twedt 1993), and may have

a competitive advantage over California redlegged frogs because of their larger size

(Figures 10 and 11), generalized food habits

(Bury and Whelan 1984), extended breeding

season (Storer 1933) that allows for

production of two clutches of up to 20,000

eggs during a breeding season (Emlen 1977),

and the unpalatability of their larvae to

predatory fish (Kruse and Francis 1977).

Lawler et al. (1999) found that fewer than 5

percent of California red-legged frogs
Recovery Plan for the California Red-legged Frog 25

Figure 10.

Comparison of

California redlegged frog (smaller)

and bullfrog

Photo © Galen Rathbun

survived in ponds with bullfrog tadpoles, and

the presence of bullfrogs delayed frog

metamorphosis.

Hayes and Jennings (1986, 1988) found a

negative correlation between the abundance

of introduced fish species and California redlegged frogs. Jennings (1988b) suspected that

native frogs do poorly where introduced

fishes are abundant because the placement of

native ranid eggs and activities of tadpoles in

shallow near-shore habitats may predispose

them to predation. However, this may be

unlikely given that introduced fish are not

typically associated with shallow, near-shore

habitat (G. Rathbun, in litt. 1999). The

interaction between tadpoles and predatory

fish may be exacerbated when they are

crowded into small pools lacking habitat

complexity (Hews 1995). Bradford (1989)

also reported a lack of co-occurrence of

native frogs and non-native fish in the same

habitat areas, which may be due to predation

by introduced fish. Many sites, particularly in

the Sierra Nevada, are now unsuitable for

California red-legged frogs because of the

presence of non-native fish. On Vandenberg

Air Force Base (Santa Barbara County), the

reproductive success of California red-legged

frogs in dune ponds with both non-native fish

and bullfrogs was nearly eliminated; in ponds

with bullfrogs but no fish, reproduction of

California red-legged frogs was evident,

though low. Reproductive rates were very

high in ponds with neither non-native fish nor

bullfrogs (S. Christopher in litt. 1998).

Mosquito abatement efforts in California

include stocking water bodies with

mosquitofish. Mosquitofish (Gambusia

affinis) are native to the eastern United States

and have been introduced to wetlands

worldwide as biological control agents for

mosquito larvae. This practice is a concern to

conservationists because introduced

mosquitofish can harm amphibians.

Mosquitofish are considered opportunistic

feeders foraging on over 50 recorded types of

plant and animal life, including micro- and

macro-invertebrates (Graf 1993).

Several studies have attempted to

demonstrate the relationship between

mosquitofish and amphibians. Studies have

also been conducted in Australia on the

effects of a closely related species, Gambusia

holbrooki, on frog tadpoles (Crinia glauerti,

C. insignifera, and Heleioporus eyrei) under
26 Recovery Plan for the California Red-legged Frog

Figure 11. Predation

of a California redlegged frog by a

bullfrog (larger frog)

Photos © David Cook

experimental conditions and on frog species

richness and abundance in the field. These

studies (Blyth 1994, Webb and Joss 1997)

showed direct predation on tadpoles, injuries

to tadpoles in tanks or ponds with Gambusia,

and reduced survival and recruitment.

Analysis of field data from Australia (Webb

and Joss 1997) demonstrated a significant

drop in the abundance of frogs when

Gambusia were present. Results of a study in

artificial ponds showed that mosquitofish and

bluegill (Lepomis machrochirus) were

significant predators of California red-legged

frog larvae (Schmieder and Nauman 1994).

Mosquitofish may also compete with

California red-legged frogs by consuming

aquatic insects that are potential food sources

for postmetamorphic frogs. Lawler et al.

(1999) observed that mosquitofish did not

affect the recruitment of red-legged frogs

from natural, spatially complex ponds.

However, although mosquitofish did not

affect red-legged frog survival, juveniles

emerging from ponds with mosquitofish

metamorphosed later and weighed an average

of one-third less than those raised without

fish. Laboratory trials showed that young

tadpoles were less active (i.e., exhibited lower

foraging levels) in the presence of fish.

Lowered activity levels could have caused a

decrease in their

initial growth rate;

injuries are also

known to decrease

the growth of

tadpoles (Lawler et

al. 1999). As has

been noted with

other amphibians,

smaller metamorphs

mature later and lay

fewer eggs;

California redlegged frogs may be

vulnerable to this

problem if they

cannot grow quickly

enough in the

terrestrial

environment to

compensate for their

initially smaller size.

Thus, sublethal

effects of mosquitofish have been

demonstrated and may provide reason enough

to consider other mosquito-control methods

in amphibian habitat and surrounding

watersheds. Effects of mosquitofish may be

greater than experimentally demonstrated if

mosquitofish are more abundant in natural

ponds when tadpoles are small. Overall, this

evidence that mosquitofish may play a role in

the decline of the red-legged frog is

inconclusive because it is based on

correlations between species distributions,

predation trials in arenas where habitat and

community structure were simplified, and, in

some cases, similar Gambusia species rather

than Gambusia affinis, specifically.

California red-legged frog larvae have been

found with mosquitofish in Corral Hollow

Creek (Alameda and San Joaquin Counties)

(T. Strange pers. comm. 1994) and in some

waterbodies in Contra Costa County (K.

Swaim in litt. 1994, Malamud-Roam in litt.

1994). California red-legged frogs may be

coexisting successfully with mosquitofish in

these cases because winter rains may flush

mosquitofish out of creeks, thus eliminating

or reducing the physical, sublethal effects

noted by Lawler et al. (1999) in pond

environments.

Overall, while California red-legged frogs are

occasionally known to persist in the presence

of either bullfrogs or mosquitofish (and other

non-native species), the combined effects of

both non-native frogs and non-native fish

often leads to extirpation of red-legged frogs

(Kiesecker and Blaustein 1998, Lawler et al.

2000, S. Christopher in litt. 1998).

In addition to non-native animals, a number

of non-native plants may threaten the

integrity of aquatic systems by out-competing

and replacing native plants and thus

decreasing plant diversity. For example,

species such as tamarisk (Tamarix sp.), giant

reed also called arundo (Arundo donax), and

cape ivy (Delaria odorata) have made

sizeable inroads into native willowcottonwood-sycamore communities in

California. These species not only change the

structure and function of a riparian corridor,

but also can result in losses of surface water
Recovery Plan for the California Red-legged Frog 27

due to their increased transpiration rates (S.

Chubb in litt. 1998). Biologists have noted

that California red-legged frogs may be

avoiding creeks and stream pools dominated

by eucalyptus (Eucalyptus spp.). The

aromatic leaves of eucalyptus trees may

secrete toxic chemicals into the water, which

may decrease the suitability of the area for

frogs (Bobzien in litt. 1998). Some biologists,

however, have also reported high numbers of

frogs in areas with poor water quality due to a

dominance of eucalyptus (e.g., West of

Bayshore property at San Francisco Airport,

Pescadero Marsh) (M. Allaback in litt. 2000,

S. Orlorff in litt. 2000). The relationship

between the presence of non-native plants

and habitat suitability for California redlegged frogs, however, is currently unknown.

Predation by Native Species. Several native

predators, including raccoons (Procyon

lotor), great blue herons (Ardea herodias),

American bitterns (Botaurus lentiginosus),

black-crowned night herons (Nycticorax

nycticorax), red-shouldered hawks (Buteo

lineatus), and garter snakes (Thamnophis

spp.) eat adult frogs (Jennings and Hayes

1990, Rathbun and Murphy 1996). Other

potential predators include opossums

(Didelphis virginiana), striped skunks

(Mephitis mephitis), and spotted skunks

(Spilogale putorius) (Fitch 1940, Fox 1952,

Jennings and Hayes 1990).

It has been noted that the release of

translocated predators, which is a common

practice of municipal animal control districts,

may threaten California red-legged frogs. For

example, in Los Padres National Forest, a

high number of raccoons and opossums were

observed in riparian areas where they were

preying upon arroyo southwestern toads

(Bufo microscaphus californicus) and

preventing successful reproduction of pond

turtles. The high number of raccoons and

opossums were due to county and city

districts practice of releasing trapped urban

wildlife into the riparian areas of the National

Forest (S. Sweet in litt. 2000).

Some native fish may also eat tadpoles (N.

Scott in litt. 1998). Reis (1999) found that

tadpoles were more likely to be absent from

study plots at Pescadero Marsh (San Mateo

County) when predaceous invertebrates were

present. These invertebrates include diving

beetles (family Dytiscidae), dragonflies

(order Odonata), and backswimmers (family

Notonectidae).

4. The Inadequacy of Existing Regulatory

Mechanisms

Although the California red-legged frog is

classified as a species of special concern by

the State of California and may not be taken

without an approved scientific collecting

permit, this designation provides no special,

legally mandated protection of the species

and its habitat.

The Endangered Species Act is the primary

Federal law that provides protection for the

California red-legged frog since its listing as

a threatened species in 1996. Since this

designation, many projects have undergone

section 7(a)(2) consultation. Section 7(a)(2)

of the Endangered Species Act requires

Federal agencies to consult with us prior to

authorizing, funding, or carrying out activities

that may affect listed species. The section

7(a)(2) consultation process provides

protection for California red-legged frogs

through reasonable and prudent measures that

minimize the amount or extent of incidental

take of the species due to project impacts.

While projects that are likely to result in

adverse effects include such minimization

measures, we are limited to requesting minor

modifications to the project description, as

proposed. Reasonable and prudent measures,

along with the terms and conditions that

implement them, cannot alter the basic

design, location, scope, duration, or timing of

the action and may involve only minor

changes. The minimization measures

typically include: (1) pre-construction

surveys, (2) capture of frogs from the

construction site and relocation into Serviceapproved on-site watercourses, and (3)

protection, enhancement, and/or creation of

habitat. The later recommendation includes

protection of California red-legged frog

habitat that already exists or creation of new

habitat which in most cases has not been

proven to be successful (i.e., California red-
28 Recovery Plan for the California Red-legged Frog

legged frogs have, for the most part, not

colonized or survived in newly created

wetlands usually due to the proximity of the

created ponds to development). Therefore,

there is typically a net loss of California redlegged frog individuals and habitat with each

authorized project. Most of these conservation measures have not been thoroughly

studied for effectiveness and therefore, may

not fully mitigate the effects of the proposed

project. Monitoring to determine the

effectiveness of these actions is required of

permit holders; however, in general neither

we nor the permit holders have fully

implemented such monitoring.

Section 404 of the Clean Water Act is another

Federal law that potentially provides some

protection for aquatic habitats of the

California red-legged frog, if the habitats are

determined to be jurisdictional areas (i.e.,

waters of the United States) by the U.S. Army

Corps of Engineers. Upland habitats adjacent

to riparian zones and other wetlands are not

provided any protection by section 404 of the

Clean Water Act. Upland areas provide

important dispersal, estivation and summer

habitat for this species.

5. Other Natural, or Manmade Factors

Affecting Their Continued Existence

Drought. Populations of most species are

cyclic in nature or fluctuate in response to

natural factors such as weather events,

disease, fire, and predation. Natural events,

including long-term drought or extreme

rainfall, have a less negative overall effect on

a species when the species is widely and

continuously distributed. Small, fragmented,

or isolated populations of a species are more

vulnerable to extirpation by random events.

As water demands increase in California due

to increasing human populations, the

interactions of those demands with natural

drought cycles may further reduce the extent

and quality of California red-legged frog

habitat and the size of remaining populations.

Decreased rain and snowfall can lead to

premature drying of streams and ponds and

subsequent death of frog eggs and larvae, and

reduced survival of subadults and adults.

Decreased surface flows in some coastal

streams [e.g., Pescadero Creek (San Mateo

County), San Simeon Creek (San Luis Obispo

County)] during drought years, coupled with

agricultural, industrial, and residential ground

water demands can result in desiccation or

increased salinity of water sufficient to kill

most if not all of 1 year’s reproduction.

Drought conditions have the potential to

eliminate a high proportion of the

reproductive effort of California red-legged

frogs in the coastal region where the largest

populations of the species remain (Jennings

and Hayes 1989). On the other hand, since

California red-legged frogs metamorphose in

1 year and bullfrog larvae require at least 2

years (Jennings 1988), occasional droughts

can benefit California red-legged frogs by

reducing the numbers of exotic fish and

bullfrogs. For example, this benefit has been

noted in the lower reaches of Brush Creek

(Contra Costa County) which dries roughly

every 3 to 5 years (M. Allaback in litt. 2000).

Contaminants. Amphibians, in general,

typically have complex life cycles and thus

more opportunities for exposure to chemicals

and more potential routes of exposure than

other vertebrates. The California red-legged

frog continues to be exposed to a variety of

toxins throughout its range. The sensitivity of

this species to pesticides, heavy metals, air

pollutants, and other contaminants is largely

unknown. Studies using other species of

amphibians, however, provide toxicity data

that are relevant to the potential vulnerability

of the California red-legged frog, as cited

below.

As mentioned above, agricultural practices

typically use pesticides including herbicides.

While some amphibian larvae (e.g., anuran

tadpoles) are resistant to some cholinesterase

inhibitors (the class of pesticides used most

often), some results indicate that this

resistance does not apply to all amphibian

species and chemicals (Sanders 1970, Cook

1981). According to Berrill et al. (1993),

ranid tadpoles are likely to be killed or

paralyzed by some herbicides (e.g., triclopyr)

and insecticides (e.g., fenitrothion). Some

pesticides mimic estrogen in vertebrates and

this has been proposed as a hypothesis for
Recovery Plan for the California Red-legged Frog 29

amphibian declines (Jennings 1996). There

are approximately 150 pesticides or

herbicides used in the same 2.6 square

kilometers (1-square mile) surveyed section

as known California red-legged frog sites or

their habitat (California Department of

Pesticide Regulation 1997). The chemicals of

greatest concern that are used within the

range of the frog are listed and described in

Appendix B.

In addition to pesticides and herbicides,

mineral fertilizers are used throughout the

range of the California red-legged frog on

crops, household lawns, and golf courses. In a

study by Schneeweiss and Schneeweiss

(1997) in Germany, up to 100 percent of

amphibians were dead in pitfall traps located

on fields that were mineral fertilized. In

contrast, no dead or injured amphibians were

found during simultaneous monitoring of

non-fertilized fields. Marco et al. (1999)

found increased mortality of northern redlegged frog larvae when exposed to nitrite

below the levels allowed for drinking water.

Additionally, Marco and Blaustein (1999)

found that Cascades frog (Rana cascadae)

larvae exposed to sublethal concentrations of

nitrite exhibited changed morphology

(delayed metamorphosis) and changed

behavior (shallow water occupancy) that

increased their vulnerability to predation.

Mercury mines have contaminated several

areas within the range of the frog (e.g., Lake

Nacimiento, Cache Creek), and chlorine has

been introduced to breeding sites via spills

and flushing of pipes used for wastewater and

drinking water treatments (e.g., Chorro

Creek). Industrial chemicals, such as these,

that are released into the environment may

damage the immune systems of frogs. For

example, one class of chemicals, known as

retinoids, causes severe defects in young

frogs; exposure to retinoids can also make

frogs more susceptible to infectious diseases

(Montague in litt. 1998). Oil seeps (either due

to natural leaks or by accidents at oil

extraction facilities) contaminate California

red-legged frog habitats. For example,

possible damage to red-legged frog tadpoles

could occur in Tar Creek, a tributary of Sespe

Creek, where an obvious oil sheen was

noticed (S. Chubb in litt. 1999).

Airborne pollutants are considered to be a

likely cause of decline of amphibians in the

Central Valley and Sierra Nevada range. For

example, basins that face the Central Valley

are nearly devoid of mountain yellow-legged

frogs and the California red-legged frog is

found in only a few locations in the western

slope of the Sierra Nevada range. The most

drastic declines of amphibians are found in

the Sierra Nevada mountains lying east of the

San Joaquin Valley; in the San Joaquin Valley

agriculture is intense and vast quantities of

pesticides are applied. For example, in 1998,

60 percent of all active ingredient pesticides

used in the State of California were applied in

the San Joaquin Valley (Sparling et al. 2001).

Particulate matter, ozone, nitrogen oxides,

herbicides, pesticides, and other air pollutants

are transported from the Central Valley into

the Sierra Nevada. Some sources of air

pollution are generated within the Sierra

Nevada, such as particulate matter generated

by smoke from forest fires and nutrient loads

and gases produced by urban areas (i.e., use

of fertilizers, traffic) (Cahill et al. 1996).

Further, the pattern of recent frog extinctions

in the southern Sierra Nevada appear to

correspond with the pattern of highest

concentrations of air pollutants from

automobile exhaust (Jennings 1996).

Researchers measured the contaminants

levels in frog and fish tissue in the Sierra

Nevada range to determine the extent of

transport and absorption. Results showed that

the concentrations and frequency of

detections for pesticides in amphibian tissue

follow north-south and west-east patterns

consistent with intensified agriculture upwind

of the areas with the most serious amphibian

declines (Sparling et al. 2001). Some of the

pesticides are reducing cholinesterase activity

in tadpoles of the Pacific treefrog. Depressed

cholinesterase has been associated with

reduced activity, uncoordinated swimming,

increased vulnerability to predators,

depressed growth rates, and greater mortality

in tadpoles (Sparling et al. 2001). Rana

species such as the California red-legged frog

may be more at risk from aqueous pesticides

than the Pacific treefrog because they are
30 Recovery Plan for the California Red-legged Frog

more reliant on aquatic environments and use

aquatic habitat in more life stages (i.e.,

Pacific treefrogs use aquatic habitat only

during breeding whereas Rana species use

aquatic habitat as tadpoles and adults).

G. REGULATORY PROTECTION AND

CONSERVATION MEASURES

Since the 1996 listing of the California redlegged frog, several conservation efforts have

been undertaken by various Federal, State,

and local agencies and private organizations.

The following briefly describes some

regulatory protection and conservation

measures accomplished to date.

Federal Regulatory Protection. Section 9 of

the Endangered Species Act of 1973, as

amended, prohibits any person subject to the

jurisdiction of the United States from taking

(i.e., harassing, harming, pursuing, hunting,

shooting, wounding, killing, trapping,

capturing, or collecting) listed wildlife

species. It is also unlawful to attempt such

acts, solicit another to commit such acts, or

cause such acts to be committed. Regulations

implementing the Endangered Species Act

(50 Federal Register 17.3) define “harm” to

include significant habitat modification or

degradation that results in the killing or injury

of wildlife, and intentional or negligent

“harassment” as acts that significantly impair

essential behavioral patterns (i.e., breeding,

feeding).

Section 10(a)(1)(A) of the Endangered

Species Act and related regulations provide

for permits that may be granted to authorize

activities otherwise prohibited under section

9, for scientific purposes or to enhance the

propagation or survival of a listed species.

Section 10(a)(1)(B) of the Endangered

Species Act allows permits to be issued for

take that is “incidental to, and not the purpose

of, carrying out an otherwise lawful activity”

if we determine that certain conditions have

been met that will minimize the impacts to

the listed species. Under this section, an

applicant must prepare a habitat conservation

plan (HCP) that specifies the impacts of the

proposed project and the steps the applicant

will take to minimize and mitigate the

impacts. There are several habitat

conservation plans currently being developed

that will include measures to protect the

California red-legged frog.

As previously described in section F. Threats

and Reasons for Decline, section 7(a)(2) of

the Endangered Species Act requires Federal

agencies, including us, to ensure that actions

they fund, authorize, or carry out do not

destroy or adversely modify critical habitat to

the extent that the action appreciably

diminishes the value of the critical habitat for

the survival and recovery of the species.

Individuals, organizations, states, local

governments, and other non-Federal entities

are affected by the designation of critical

habitat only if their actions occur on Federal

lands, require a Federal permit, license, or

other authorization or involve Federal

funding.

Since the listing, we have entered into section

7(a)(2) consultations with other Federal

agencies on numerous project proposals per

the requirements of the Endangered Species

Act. Examples include interagency section

7(a)(2) consultations on proposed road

construction and maintenance, housing

developments and golf courses that involve

wetland fill, timber harvest activities,

livestock grazing practices, and other

activities within the current and historic range

of the species.

On March 13, 2001, we finalized the

designation of critical habitat for the

California red-legged frog (U.S. Fish and Wildlife Service 2001). Critical habitat is

defined as specific areas that have been found

to be essential to the conservation of the

species and which may require special

management considerations or protection.

The primary constituent elements for

California red-legged frogs are aquatic and

upland areas where suitable breeding and

nonbreeding habitat is interspersed

throughout the landscape and is

interconnected by unfragmented dispersal

habitat. Specifically, to be considered to have

the primary constituent elements an area must

include two (or more) suitable breeding
Recovery Plan for the California Red-legged Frog 31

locations, a permanent water source,

associated uplands surrounding these water

bodies up to 91 meters (300 feet) from the

water’s edge, all within 2 kilometers (1.25

miles) of one another and connected by

barrier-free dispersal habitat that is at least 91

meters (300 feet) in width. When these

elements are all present, all other essential

aquatic habitat within 2 kilometers (1.25

miles), and free of dispersal barriers, will be

afforded some protection under section

7(a)(2) of the Endangered Species Act.

Federal Conservation Measures. Section

7(a)(1) of the Endangered Species Act

requires that Federal agencies use their

authorities to further the conservation of

listed species. Section 7(a)(1) obligations

have caused Federal land management

agencies to implement California red-legged

frog protection measures that go beyond

those required to avoid take. Some of these

conservation measures are described below.

Los Padres National Forest has completed a

forest-wide Riparian Conservation Strategy

that augments and amends the Forest Land

and Resource Management Plan (U.S. Forest

Service 1988). This management plan (with

the added riparian conservation strategy)

provides management guidelines for the

conservation of riparian habitats and

associated species. Conservation actions

include: riparian management guidelines,

administration of water flow and use,

management of non-native species,

reintroduction of native species, recreational

guidelines, livestock grazing guidelines,

mining and prospecting guidelines, road

maintenance guidelines, land exchanges,

acquisition and sales programs, management

of watershed activities, and species and

habitat inventories. Pursuant to the Los

Padres National Forest Plan Riparian

Conservation Strategy and anadromous

steelhead recovery efforts, landscape-based

watershed analyses of the Sespe, Santa Paula,

Ventura, Santa Ynez, and Arroyo Seco

watersheds have been conducted. These

efforts are likely to benefit the California redlegged frog through more effective and

efficient protection measures and coordinated

restoration projects. Other beneficial

activities which have been conducted on this

Forest include non-native species removal

(e.g., bullfrogs and green sunfish),

streambank stabilization and revegetation,

road closures, modifications to permitted

water diversions (e.g., Upper Santa Ynez

River), restrictions on recreational activities,

educational programs, and assessment and

monitoring of California red-legged frog

abundances and habitat use. In this region,

Vandenberg Air Force Base has also been

protecting California red-legged frogs and

their habitats.

The Cleveland National Forest has completed

extensive surveys of historic and potential

habitat for California red-legged frogs, but no

frogs were located. However, the Forest has

management direction, such as livestock

grazing guidelines and management practices,

to maintain suitability of riparian corridors.

The Cleveland National Forest has excluded

grazing from most perennial riparian habitats

on the forest. Where exclusion is not feasible,

the Forest has changed the season of use to

winter; presumably cattle graze to a lesser

degree in breeding habitats during the winter

because forage is available in the uplands

during the moist winter season. Further, the

Forest is removing non-native species (e.g.,

arundo, tamarisk, bullfrogs) and redesigning

road crossings on Pine, Morena, and Santa

Ysabel Creeks (S. Chubb in litt. 1998).

The Cleveland, San Bernardino, Angeles, and

Los Padres National Forests have completed

a Southern California Mountain and Foothills

Assessment, which has added standards,

guidelines, and conservation measures to

protect and recover wetland and upland

habitats of importance to California redlegged frogs and associated species (S. Chubb

in litt. 1998). This program has gone through

our section 7 consultation process.

The Sierra National Forest is currently

surveying for California red-legged frogs.

This Forest is also implementing our

recommendations related to timber sales, and

is developing a management plan for offhighway vehicles that should minimize

impacts to California red-legged frogs.

Similarly, the Tahoe National Forest is
32 Recovery Plan for the California Red-legged Frog

conducting forest-wide surveys for California

red-legged frogs and other amphibians. In

addition to following the Forest’s general

guidelines, which include management and

protection of riparian habitats and protection

of threatened and endangered species, the

Tahoe National Forest has proposed projects

to plant riparian vegetation along streams and

fences with potential California red-legged

frog habitat and to exclude recreational

activities.

The Eldorado National Forest, with assistance

from the Biological Resources Division of the

U.S. Geological Survey, has conducted

surveys for California red-legged frogs in

streams that have potential habitat. No redlegged frogs have been observed during any

of the surveys, and the habitat suitability is

poor. Near Eldorado National Forest, the

American River Conservancy has taken the

lead in facilitating the purchase of 20 hectares

(55 acres) of land that encompasses Spivey

Pond on the North Fork of Weber Creek, the

location of a breeding California red-legged

frog population. A memorandum of

understanding was signed by the U.S. Bureau

of Land Management American River

Conservancy, California Department Water

Resources, U.S. Forest Service, U.S. Fish and

Wildlife Service, U.S. Bureau of

Reclamation, and El Dorado Irrigation

District to support a management plan for the

property and the frog population (S. Chubb in

litt. 1999). This management plan is currently

being crafted and the U.S. Bureau of Land

Management is now the property owner.

The Bureau of Land Management has

developed, and is implementing, national

standards and guidelines for livestock

grazing. The standards and guidelines relate

to vegetative ground cover, riparian-wetland

function, stream morphology, water quality,

and threatened and endangered species

recovery. Several of the guidelines should

indirectly help maintain California red-legged

frog habitat quality. Assessments of whether

grazing allotments are meeting these

guidelines are expected to be completed

within 5 years; allotments not meeting the

standards will be subject to additional

management. In 1991, the Bureau of Land

Management developed a Riparian-Wetland

Initiative that established national goals and

objectives for managing riparian-wetland

resources on public lands. One of the chief

goals of this initiative is to restore and

maintain riparian-wetland areas so that at

least 75 percent or more are in proper

functioning condition. Riparian areas that

meet the proper functioning condition, or are

restored to such condition, may provide the

habitat quality necessary for successful

colonization and/or reintroduction of

California red-legged frogs (E. Lorentzen in

litt. 1998).

The National Resource Conservation Service

has carried out the Elkhorn Slough Watershed

Project. This program was established with

farmers within the watershed to implement

measures to reduce sedimentation and runoff

and to restore habitat.

The Golden Gate National Recreation Area

(National Park Service) has developed several

programs that provide benefits to the

California red-legged frog. Several site

management plans have been developed that

will provide protection for California redlegged frogs. For example, the Milagra Ridge

and Wolfback Ridge Management Plans

include plans for removal of non-native plant

species from riparian corridors, revegetation

with native riparian plants, maintenance of

water-diversion structures to improve water

flow, soil erosion control, and outreach/

environmental education (National Park

Service 1995, 1996). Further, the Golden

Gate National Recreation Area has initiated a

tiered, volunteer-based monitoring program

for surveying for frogs during the winter in

three watersheds (Tennessee, Lower

Redwood/Big Lagoon, and Rodeo Valley).

The Golden Gate National Recreation Area

has also developed plans to restore several

areas within its jurisdiction, such as Mountain

Lake in the Presidio in coordination with the

City of San Francisco, and Big Lagoon in

Marin County. The Golden Gate National

Recreation Area is also implementing nonnative aquatic animal control programs in

Tennessee and Oakwood valleys to protect

California red-legged frogs and western pond

turtles (Shinomoto and Fong 1997, D. Fong,

in litt. 1998).
Recovery Plan for the California Red-legged Frog 33

The CALFED Program is a comprehensive,

30-year plan to restore ecosystems and

improve water management for beneficial

uses of the San Francisco Bay and

Sacramento-San Joaquin River Delta. The

CALFED Program is managed cooperatively

by 14 Federal and State agencies with

management responsibilities in the Bay-Delta

region. The CALFED Program vision for the

California red-legged frog is to maintain

populations. The CALFED Program is

expected to restore aquatic, wetland, and

riparian habitats in the Sacramento-San

Joaquin Delta Ecological Management Zone

and other ecological management zones

which will help in the recovery of the frog by

increasing habitat quality, connectivity, and

area (CALFED Bay-Delta Program 2000).

Specifically, the CALFED Program included

in the Multi-Species Conservation Strategy

goals to enhance or restore suitable habitats

near occupied habitat and to avoid or

minimize CALFED actions that could

increase or attract non-native predator

populations to occupied habitat (CALFED

Bay-Delta Program 2000).

Measures Implemented by California State

Resource Agencies. The California redlegged frog is classified as a “Species of

Special Concern” by the State of California

(Steinhart 1990). This designation provides

no special, legally mandated protection of the

species and its habitat, but does mandate that

the species not be taken without an approved

scientific collecting permit. In 1972, the

California Fish and Game Commission

amended its sport fishing regulations to

prohibit take or possession of California redlegged frogs (Bury and Stewart 1973). The

designation of species of special concern can

confer additional protection to species via

section 15380 of the California

Environmental Quality Act guidelines. This

section requires lead agencies under the

California Environmental Quality Act to treat

species as de facto State threatened or

endangered if they appear to meet listing

requirements. For many unlisted species

which are currently species of special

concern, this designation can afford

additional consideration under California

Environmental Quality Act review.

Section 1600 of the California Fish and Game

Code authorizes the Department of Fish and

Game to enter into agreements with parties

seeking to perform activities within the bed,

bank, or channel of any stream, lake or river.

Section 1603 of the California Fish and Game

Code authorizes the Department of Fish and

Game to regulate streambed alteration for

private entities or individuals. The

Department must be notified, and approve

any work that substantially diverts, alters, or

obstructs the natural flow or substantially

changes the bed, channel or banks of any

river, stream, or lake. If an existing fish or

wildlife resource may be substantially

adversely affected by a project, the

Department must submit proposals to protect

the species within 30 days; this regulatory

procedure should provide some protection for

California red-legged frog populations and

habitat.

In 1996, the California Department of

Forestry and Fire Protection requested our

assistance in determining protective measures

for timber harvest plans and non-industrial

timber management plans to avoid take of the

California red-legged frog. Through this

process, we developed guidelines that can be

applied, by California Department of Forestry

and Fire Protection inspectors or other forest

professionals, to any timber harvest plan or

non-industrial timber management plans

within the range of the frog. In addition to

providing a dichotomous key to assessing

potential impacts to the California red-legged

frog, the guidelines also recommend

avoidance measures, which reduce the

likelihood of incidental take of the species

(U.S. Fish and Wildlife Service 1996c).

California Department of Forestry and Fire

Protection enforces the California Forest

Practice Rules (California Department of

Forestry and Fire Protection 1999), which

provide prescriptive and procedural rules that

protect watercourses and lakes, and provide

some protection for California red-legged

frog against timber harvest and related

activities. Conservation measures were

developed by the California Department of

Forestry and Fire Protection and the

California Department of Fish and Game
34 Recovery Plan for the California Red-legged Frog

pursuant to the California Endangered

Species Act consultation process, for

Registered Professional Foresters. These are

to be applied in areas immediately adjacent to

coho salmon (Oncorhynchus kisutch) habitat

south of San Francisco Bay. The protection

measures for coho salmon will benefit

California red-legged frogs occurring in

Pescadero, Gazos, San Gregario, and Butano

Creeks in San Mateo County; and Aptos,

Scott, Soquel, San Vincente, and Waddell

Creeks and the San Lorenzo and Pajaro

Rivers in Santa Cruz County (B. Valentine in

litt. 1998).

The California Department of Parks and

Recreation has programs that benefit the

California red-legged frog. Special park

designations (i.e., Natural Preserves and State

Reserves), provide increased protection of the

land and for resident sensitive species,

including the California red-legged frog.

Development of general plans, resource

management plans, site management plans,

and resource inventories are ongoing within

the Department and allow planning for

special status species. Other planning efforts

include developing habitat conservation plans

with us. Currently, a regional habitat

conservation plan is being developed for San

Luis Obispo Coast and Oceano Dunes

districts, and another is being developed for

Carnegie State Vehicular Recreation Area.

Both will benefit the California red-legged

frog.

Restoration and enhancement efforts in many

State park areas include riparian and wetland

habitats. The following are some examples of

park wetland restoration projects that

benefitted the California red-legged frog. At

Pescadero Marsh Natural Preserve, within

Pescadero State Beach, the California

Department of Parks and Recreation

developed and implemented a wetland

restoration project to enhance habitat

suitability for the California red-legged frog.

Restoration actions include enlargement of

existing breaches in the levees, and

connection of remnant channels, removal of a

tide gate, excavation of channels,

management of the Nunziatti trout ponds, and

a one-season experimental bullfrog control

program in Pescadero Marsh (T. Sasaki in litt.

1999). Año Nuevo State Reserve has

undertaken intensive bullfrog removal efforts

in ponds inhabited by California red-legged

frogs (I. Loredo in litt. 1998). The Santa Cruz

District completed a 7 hectare (20 acre)

restoration project at Wilder Creek Natural

Preserve, converting 3.5 hectares (10 acres)

of lowland and streamside agricultural fields

to willow and wetlands, allowing Wilder

Creek to escape the dredged channel during

high water events. California red-legged frogs

appeared and reproduced in high numbers

shortly after the project began, and the frogs

continue to use the area (T. Sasaki in litt.

1999). M. Allaback (in litt. 2000) observed

numerous frogs before the restoration in the

early 1990s suggesting that a significant

population was already present. The San

Simeon District is currently restoring

wetlands adjacent to San Simeon Creek, and

is in the process of requesting funds to

purchase a small, unnamed drainage used by

red-legged frogs during periods of high

salinity in the lagoon. This district also

conducts biannual surveys to monitor

California red-legged frogs and bullfrogs,

removes non-native plant species, removes

predators such as raccoons and feral cats, and

monitors water quality (G. Smith pers. comm.

1998).

The California Army National Guard has

sponsored California red-legged frog surveys

at Camp Roberts (San Luis Obispo and

Monterey Counties) and at Camp San Luis

Obispo (San Luis Obispo County) (N. Scott

in litt. 1999). These surveys are used to

monitor red-legged frog numbers at known

and potential sites, status of habitat,

reproduction and occurrence of red-legged

frog predators. In 1994, the California Army

National Guard fenced a section of riparian

habitat along Chorro Creek at Camp San Luis

Obispo to eliminate cattle grazing;

approximately 4,500 native plants were

planted within the exclosure to restore

riparian habitat. This exclosure has enhanced

habitat for the California red-legged frog. The

California Army National Guard also began a

bullfrog eradication program and a giant reed

and invasive plant removal program in 1999,

at known and potential red-legged frog sites
Recovery Plan for the California Red-legged Frog 35

at Camp San Luis Obispo. In this area, the

National Guard has also repaired roads and

trails, eroded areas and reduced sedimentation into creeks, ponds, and reservoirs, and

has planted willows; all of these actions have

increased habitat suitability by enhancing

aquatic and riparian habitats.

Section 6(d) of the Federal Endangered

Species Act allows us to provide financial

assistance to the State to assist in

development of programs for the

conservation of endangered and threatened

species or to assist in monitoring the status of

candidate species. Through this program we,

along with the California Department of Fish

and Game, have funded several projects that

have benefitted the California red-legged

frog. For example, surveying and monitoring

of the Sierra Nevada foothills have been

funded through section 6(d), as were

restoration activities at Calabasas Pond (Santa

Cruz County).

Municipal Protection Measures. Regional,

county, and city park districts and regional

water and municipal utility districts have

played a role in conserving habitat for the

California red-legged frog. Some counties are

preparing county-wide habitat conservation

plans that will benefit the California redlegged frog (e.g., San Benito County, Contra

Costa County). The East Bay Regional Park

District encompasses 59 regional parks,

recreation and wilderness areas, shorelines,

preserves and other land bank areas in Contra

Costa and Alameda Counties, covering over

33,000 hectares (91,000 acres). The East Bay

Regional Park District has surveyed ponds

and streams within its jurisdiction, has

restored several ponds and streams, and plans

to restore additional areas, to benefit

California red-legged frogs. Biologists from

the Santa Clara Valley Water District and East

Bay Municipal Utility District have surveyed

many areas within the districts for California

red-legged frogs; the Santa Clara Valley

Water District has plans to expand the survey

program in upcoming years (D. Padley pers.

comm. 1998). The Contra Costa Water

District actively manages the Los Vaqueros

watershed (Upper Kellogg Creek drainage)

for California red-legged frogs by adjusting

water levels in ponds, removing predatory

fishes, reducing grazing impacts, minimizing

human disturbances, planting wetland and

riparian vegetation, offering public education

programs and developing guidelines for fire

management practices to decrease incidental

impacts to California red-legged frogs. These

activities have contributed to the expansion of

the range of the frog within the watershed and

have helped to increase breeding success (J.

Alvarez in litt. 2000).

Protection on Private Lands. Private

landowners interested in conservation efforts

for riparian habitats have made important

contributions to recover the California redlegged frog. Since 1990, our Partners for Fish

and Wildlife program has provided cost-share

monies and technical assistance to private

landowners throughout the state who

undertake fish and wildlife habitat restoration

projects. To date, the Partners for Fish and

Wildlife program has helped fund six projects

to improve habitat in creeks that support

California red-legged frogs. In 1997, three

projects were carried out in Toro Creek in San

Luis Obispo County. Restoration activities

included stabilization of eroding streambanks

and planting of riparian vegetation. In

Sonoma County, eroding streambanks were

stabilized and riparian vegetation was planted

in 1996 and 1997 in Stemple Creek (D. Strait

in litt. 1998).

In 1995, the livestock industry agreed to

become involved in developing a cooperative

approach to meet the regulatory requirements

in place for nonpoint source pollution

associated with rangeland practices by

allowing land owners to voluntarily develop

and implement California Rangeland Water

Quality Management Plans. The plans are

limited to non-Federal rangelands, pasture

and other grazed lands of California (G.

Humiston in litt. 1995).

Interagency and Private Cooperative

Efforts. Throughout the range of the

California red-legged frog there are many

cooperative efforts aimed at restoring and

preserving wetland ecosystems and

maintaining or increasing biodiversity. These

groups or projects are typically comprised of
36 Recovery Plan for the California Red-legged Frog

some combination of Federal, State, and

municipal agencies as well as nongovernment organizations and private

citizens. They demonstrate the commitment

that the private sector exhibits regarding

conservation as well as the productivity that

can result when multiple groups collaborate.

One example includes the project named

Biodiversity in the Santa Cruz Mountains.

This project is involved in an inventory of

biodiversity in the Santa Cruz mountains as

well as a threats assessment. Cooperators

include us, the California Department of Fish

and Game, and the Santa Cruz Mountains

Bioregional Council. Another example is the

Carmel River Watershed Management Plan,

which aims to assess conditions in the

watershed and recommend a water

management plan that will restore the river to

a level of productivity while benefitting

wildlife species including the California redlegged frog. Cooperators involved in this

effort include the California Department of

Fish and Game, the U.S. Forest Service, and

the Monterey Peninsula Water Management

District. The Watsonville Slough’s Water

Resources Management Plan is being

developed to improve water quality in

Watsonville Sloughs freshwater marsh

system. This effort involves Federal, State,

and municipal agencies as well as the

University of California, and Watsonville

Wetland Watch. The Elkhorn Slough

Watershed Project’s purpose is to reduce

sediment and pesticide delivery to wetlands

by working cooperatively with private

landowners and tenants to reduce agricultural

erosion and runoff. Similarly, the Pajaro

River Management Plan is being developed

by a large group of collaborators to address

flood control and environmental preservation

of this river. Many other examples exist as

listed by the Information Center for the

Environment, which maintains a website that

includes the California Watershed Projects

Inventory (http://ice.ucdavis.edu).

Surveys and Research. In addition to the

efforts of Federal, State, local, and private

entities, status surveys for California redlegged frogs and research on the ecology of

this species have been conducted by several

research groups. The Western Ecological

Research Center of the Biological Resources

Division (part of the U.S. Geological Survey)

has several ongoing research projects. The

Piedras Blancas Field Station of the Western

Ecological Research Center has a research

program in progress that is focused on radiotracking the movements of adult California

red-legged frogs in pastures and forested

habitats in both San Luis Obispo and Santa

Cruz Counties. Another project, which

involves monitoring population dynamics and

ecology of California red-legged frogs in

coastal streams in San Luis Obispo County, is

contributing data on population fluctuations

and turnover, movements, and reproductive

behavior. This research group is also

examining the effects of non-native frogs and

fishes on California red-legged frogs on

Vandenberg Air Force Base, Santa Barbara

County. The Western Ecological Research

Center field station at Point Reyes National

Seashore is conducting surveys for California

red-legged frogs in the Sierra Nevada

foothills. In addition, they are investigating

the interactions between California redlegged frogs and livestock in pond sites at

Point Reyes National Seashore, Marin

County, and are tracking frogs to determine

habitat use at breeding sites and to monitor

dispersal habits in the Olema Valley.

Research groups associated with many

universities (e.g., University of California at

Davis, Sonoma State University, San Jose

State University) are investigating the

genetics and life history of California redlegged frogs and providing valuable

information regarding distribution,

systematics, habitat requirements, and life

history (Cook 1997).

We have been actively working with multiple

conservation partners in southern California

on developing a captive rearing and

propagation program to augment existing

populations of red- legged frogs and reestablish frogs into historic localities. These

partners include the Los Angeles Zoological

Society, The Nature Conservancy, The Las

Virgenes Institute, and Center for Scientific

Research and Higher Education in Ensenada,

Baja California, Mexico. These efforts have

concentrated on two separate programs.
Recovery Plan for the California Red-legged Frog 37

Table 2. Sensitive fish species and wildlife associated with the California red-legged frog.

 Taxa (Scientific name) Federal Status/State Status

 California freshwater shrimp (Syncaris pacifica) endangered/endangered

Tomales asellid (Caecidotea tomalensis) species of concern/no status

 California tiger salamander (Ambystoma californiense) candidate/species of special concern

 Distinct Population Segment in Santa Barbara County endangered/species of special concern

 Santa Cruz long-toed salamander (Ambystoma macrodactylum croceum) endangered/endangered

 foothill yellow-legged frog (Rana boylii) species of concern/species of special concern

 mountain yellow-legged frog (Rana muscosa) species of concern/species of special concern

 arroyo southwestern toad (Bufo microscaphus californicus) endangered/species of special concern

 western spadefoot toad (Scaphiopus hamondii) species of concern/species of special concern

Alameda whipsnake (Masticophis lateralis euryxanthus) threatened/threatened

 two-striped garter snake (Thamnophis hammondii) species of concern/no status

 San Francisco garter snake (Thamnophis sirtalis tetrataenia) endangered/endangered

 western pond turtle (Clemmys marmorata) species of concern/species of special concern

 tidewater goby (Eucyclogobius newberryi) endangered/species of special concern

 unarmored threespine stickleback (Gasterosteus aculeatus williamsoni) endangered/endangered

 coho salmon (Oncorhynchus kisutch) varies by evolutionarily significant unit

 steelhead trout (Oncorhynchus mykiss) varies by evolutionarily significant unit

 tricolored blackbird (Agelaius tricolor) species of concern/species of special concern

 little willow flycatcher (Empidonax traillii brewsteri) species of concern/endangered

 southwestern willow flycatcher (Empidonax traillii extimus) endangered/endangered

 saltmarsh common yellowthroat (Geothlypis trichas sinuosa) species of concern/species of special concern

 least Bell’s vireo (Vireo bellii pusillus) endangered/endangered

 marsh sandwort (Arenaria paludicola) endangered/endangered

 Gambel’s watercress (Rorippa Gambellii) endangered/threatened

The first program is the augmentation and reestablishment of the red-legged frog at the

Santa Rosa Plateau Ecological Reserve in

southwestern Riverside County. This effort

has concentrated on a cooperative effort with

The Los Angeles Zoo, The Nature

Conservancy, and the Center for Scientific

Research and Higher Education in Ensenada,

Baja California, Mexico, to collect frogs from

an apparently genetically similar (genetics to

be verified) breeding population in Baja

California to re-establish a breeding

population at the Reserve. Once reestablished and stabilized, this population

will be used as a source population to reestablish frogs into appropriate habits in

southern California.

The second program consists of a cooperative

effort between us, the Los Angeles Zoo, and

the Las Virgenes Institute to monitor an

extant breeding population in the Los Angeles

basin and develop a captive rearing,

propagation, and release protocol. After

monitoring the population for several years to

establish the size and breeding success,

several metamorphs were brought into

captivity to develop a captive rearing protocol

and head-start program. This effort was

expanded to include tadpoles and will be

further expanded to include captive rearing

and breeding ponds. Frogs from these ponds

will eventually be used to re-establish frogs

into historic localities in the norther portion

of the Los Angeles basin.
38 Recovery Plan for the California Red-legged Frog

Recovery plans shall be developed

and implemented in a manner that

conserves the biotic diversity of the

ecosystem upon which the listed

species depend.

The knowledge learned through both of these

programs will facilitate the development of

standardized protocols for rearing, breeding,

and re-establishment efforts for the redlegged frog that can be used throughout the

species’ range in California and possibly

Mexico.

H. ASSOCIATED SPECIES

We are committed to applying an ecosystem

approach to conservation to promote efficient

and effective conservation of our Nation’s

biological diversity (U. S. Fish and Wildlife

Service 1994b). In recovery plans, it is our

policy to incorporate ecosystem

considerations by:

1) Developing and implementing recovery

plans for communities or ecosystems

where multiple listed species and species

of concern occur;

2) Developing and implementing recovery

plans for threatened and endangered species in a manner that

restores, reconstructs,

or rehabilitates the

structure, distribution, connectivity,

and function upon

which those listed

species depend. In

particular, these

recovery plans shall

be developed and

implemented in a

manner that conserves the biotic

diversity of the

ecosystems upon which the listed species

depend;

3) Expanding the scope of recovery plans to

address ecosystem conservation by

enlisting local jurisdictions, private

organizations, and affected individuals in

recovery plan development and

implementation; and

4) Developing and implementing agreements

among multiple agencies that allow for

sharing of resources and decision making

on recovery actions for wide ranging

species.

The current emphasis on multiple species

protection and management reflects a

recognition of the way organisms interact

with each other and their environments. By

developing and implementing conservation

measures aimed at restoring and protecting

the processes that maintain healthy ecosystems, future listings may be prevented. There

are several listed, proposed, or candidate fish,

wildlife and plant species that occur in, or

near, streams and wetlands that either historically supported, or currently support

California red-legged frog populations (Table

2). Some of these species are included in

existing or developing recovery plans. In

these cases, actions taken to recover the

California red-legged frog will also contribute

to implementation of these recovery plans

(e.g., California freshwater shrimp,

southwestern willow flycatcher, least Bell’s

vireo, arroyo southwestern toad). Other

species that are not covered by regulatory

processes or existing recovery planning

efforts (e.g., foothill yellow-legged frog,

mountain yellow-legged frog, western pond

turtle, California tiger salamander, neotropical migratory songbirds), should also benefit

from implementation of the California redlegged frog recovery plan through improvements in wetland habitats where the ranges

overlap with California red-legged frogs.

California freshwater shrimp. The California

freshwater shrimp (Syncaris pacifica) is

endemic to perennial streams in Marin, Napa,

and Sonoma Counties, California, and is the

only existing species in the genus Syncaris.

The species is adapted to freshwater

environments and has not been found in

brackish or estuarine environments. The

shrimp is found in low elevation (less than 16

meters [52 feet]) and low gradient (less than 1

percent) streams where banks are structurally
Recovery Plan for the California Red-legged Frog 39

diverse with undercut banks, exposed roots,

overhanging woody debris, or overhanging

vegetation (Eng 1981, Serpa 1986, 1991).

The shrimp is threatened by several types of

human activities (e.g., urbanization, in-stream

gravel mining, overgrazing, agricultural

development and activities, impoundments,

water diversions, water pollution, and

introduced predators). Many of these threats

operate synergistically and cumulatively with

each other and with natural disturbances such

as floods and droughts (U.S. Fish and

Wildlife Service 1997a).

Tomales asellid. The asellid (Caecidotea

tomalensis), an aquatic sowbug, inhabits

moist soils or water bodies with perennial

flows although it has been found in seasonal

wetlands (Shinomoto and Fong 1997). In

general, freshwater isopods, such as the

Tomales asellid, are associated with shallow

waters less than 1 meter (3 feet) deep, and are

found under rocks, vegetation, and debris

(Serpa 1991). The Tomales asellid is known

from just 11 sites within California, from

Mendocino County to San Mateo County

(Serpa 1991).

California tiger salamander. The historic

distribution of the California tiger salamander

(Ambystoma californiense) apparently

included large portions of the Central Valley

of California, from the southern Sacramento

Valley north of the Sacramento River delta

into the southern San Joaquin Valley. The

salamander also was found in the lower

foothills along the eastern side of the Central

Valley and in the foothills of the Coast

Ranges (U.S. Fish and Wildlife Service

1994c).

The salamander occurs in grasslands and

open oak woodlands. Necessary habitat

components include rodent burrows for

underground retreats and breeding ponds,

such as artificial stockponds, seasonal

wetlands, vernal pools, or slow-moving

streams, that do not support fish. Because the

salamander may migrate up to a mile

(approximately 1.5 kilometers) from its

underground retreats to breeding ponds,

unobstructed migration corridors are also

required (U.S. Fish and Wildlife Service

1994c).

Most of the remaining range of the California

tiger salamander is threatened by urban

development, conversion of natural habitat

and grazing lands to seasonal crops,

vineyards, and orchards, introduction of nonnative predatory animals, construction of

reservoirs, poisoning campaigns to destroy

rodents, environmental pollution, and other

anthropogenic factors (U.S. Fish and Wildlife

Service 1994c, Stebbins and Cohen 1995).

Santa Cruz long-toed salamander. The Santa

Cruz long-toed salamander (Ambystoma

macrodactylum croceum)

spends most of its life

underground in small

mammal burrows and along the

root systems of plants in upland

chaparral and woodland areas of coast live

oak (Quercus agrifolia) or Monterey pine

(Pinus radiata) as well as in riparian strips of

arroyo willows (Salix lasiolepis). The

breeding ponds are usually shallow,

ephemeral, freshwater ponds or quiet, marshy

areas of sloughs. Adult Santa Cruz long-toed

salamanders leave their upland chaparral and

woodland summer retreats with the onset of

the rainy season in mid- to late-November or

December, and begin their annual nocturnal

migration to the breeding pond (Anderson

1960).

Breeding of Santa Cruz long-toed

salamanders has been documented at Valencia

Lagoon, Ellicott, Seascape, Calabasas, Buena

Vista, Green, and Rancho Road ponds in

Santa Cruz County and at McClusky, Moro

Cojo, and Bennett sloughs, and McClusky

vernal pool in Monterey County. However,

many of these sites have not been surveyed

recently and may no longer support breeding

populations. Juvenile Santa Cruz long-toed

salamanders have also been found at several

other sites in Santa Cruz and Monterey

Counties (Natural Diversity Database 2001).

The extremely restricted and disjunct

distribution of the Santa Cruz long-toed

salamander has made the species particularly

susceptible to population declines resulting

from both human-associated and natural

factors, including habitat loss and

degradation, predation by introduced and
40 Recovery Plan for the California Red-legged Frog

native organisms, and weather conditions.

Highway construction, urban and agricultural

development, siltation, off-highway vehicles,

non-native fish and vegetation, and saltwater

intrusion are some of the perturbations

affecting Santa Cruz long-toed salamander

habitat.

Foothill yellow-legged frog. Within the range

of the California red-legged frog, the foothill

yellow-legged frog (Rana boylii) occurs

along the central coast and in the Sierra

Nevada (Leonard et al. 1993). The foothill

yellow-legged frog is confined to the

immediate vicinity of permanent streams,

including those that may be reduced to water

holes connected by trickles during the dry

season. The frogs are most common along

streams having rocky, gravelly, or sandy

bottoms, but they may occur in those having

muddy bottoms (Nussbaum et al. 1983).

Introduced predators, habitat fragmentation,

and disease seem to be important factors in

the decline of this species (Jennings 1996).

Mountain yellow-legged frog. Before the late

1960s, mountain yellow-legged frogs (Rana

muscosa) were abundant in southern

California stream drainages. The mountain

yellow-legged frog originally inhabited

riverbanks, meadow streams, isolated pools,

and lake borders in the Sierra Nevada above

1,370 meters (4,500 feet) from Butte Creek,

Plumas County, south to Taylor Meadow,

Tulare County, California and also occurred

in streams in the Palomar, San Bernardino,

San Gabriel, and San Jacinto mountain ranges

in southern California between 400 meters

(1,300 feet) and 2,300 meters (7,500 feet)

(Jennings and Hayes 1994). The southern

California population of mountain yellowlegged frogs has probably been extirpated

from more than 99 percent of its historic

range (U.S. Fish and Wildlife Service 1997b).

This species is threatened by non-native

aquatic predators, changes in streamflows,

land use practices, loss of habitat, possibly a

sensitivity to ultraviolet radiation and urban

atmospheric pollution, and various other

natural and human caused factors throughout

its range (U.S. Fish and Wildlife Service

1997c).

Arroyo southwestern toad. The arroyo

southwestern toad (Bufo microscaphus

californicus) is restricted to rivers that have

shallow, sandy to gravelly pools adjacent to

sandy terraces. Breeding occurs on small to

medium streams and rivers with persistent

water from late March until mid-June (Sweet

1989). Historically, arroyo southwestern

toads were found in coastal drainages in

southern California from San Luis Obispo

County to San Diego County and in Baja

California, Mexico (US Fish & Wildlife

Service 1999). In Orange and San Diego

Counties, the species occurred in low gradient

stream reaches. Arroyo southwestern toads

now survive primarily in the headwaters of

coastal streams as small isolated populations.

In 1996, they were discovered on Fort Hunter

Liggett in Monterey County. Urbanization

and dam construction beginning in the early

1900s in southern California caused most of

the extensive habitat degradation. Mining,

livestock grazing, and recreational activities

in riparian areas have also degraded habitat

(U.S. Fish and Wildlife Service 1994d).

Arroyo southwestern toads historically

occurred with California red-legged frogs in

the Transverse and Peninsular ranges. They

still occur in the same streams on the Los

Padres National Forest.

Western spadefoot toad. Spadefoot toads are

olive-brown or gray, with dark blotches and

little red bumps. Adults have a light-colored,

hourglass pattern on their back. In adult

males, the smooth skin of the throat is

charcoal-gray. The young are nearly the same

color as adults, but they do not have the

hourglass pattern on their backs. They have a

tiny black shovel (spade) on each hind foot.

Spadefoot toads use grasslands and breed in

natural vernal pools and man-made stock

ponds. Western Spadefoots have now largely

disappeared in lowland southern California,

although populations remain in other parts of

the State. Western spadefoot toads occur in

the same areas as California red-legged frogs

in several areas including the Corral Hollow

watershed (Alameda and San Joaquin

Counties), Sunol Regional Wilderness

(Alameda County), and Simon Newman

Ranch (Santa Clara County).
Recovery Plan for the California Red-legged Frog 41

Alameda whipsnake. The Alameda

whipsnake (Masticophis lateralis

euryxanthus) occurs in northern coastal scrub,

chaparral, and adjacent habitats in the inner

coast ranges of western and central Contra

Costa and Alameda Counties. Five

populations of the whipsnake are centered in

the (1) Sobrante Ridge, Tilden/Wildcat

Regional Parks area to the Briones Hills, in

Contra Costa

County, (2)

Oakland Hills,

Anthony Chabot

area to Las Trampas Ridge, in

Contra Costa County; (3) Hayward Hills,

Palomares area to Pleasanton Ridge, in

Alameda County; (4) Mount Diablo vicinity

and the Black Hills, in Contra Costa County;

and (5) Wauhab Ridge, Del Valle area to the

Cedar Mountain Ridge, in Alameda County.

The Alameda whipsnake and its habitat are

threatened by commercial and residential

development, fire suppression,

overcollecting, competition from alien plants,

inappropriate grazing levels, off-road vehicle

use, and random chance events by virtue of

their small numbers and small, fragmented

population sizes (U.S. Fish and Wildlife

Service 1996d).

Two-striped garter snake. The two-striped

garter snake (Thamnophis hammondii) lacks a

middorsal stripe, having pale to indistinct

lateral stripes on an olive, brown, or

brownish-gray background color. Individuals

usually have dark spots dorsal to the lateral

stripes, but no red on the sides. The species

occurs in or near permanent fresh water

streams in coastal, transverse, and peninsular

ranges from Monterey County, California, to

northwestern Baja California. Two-striped

garter snakes forage on all life stages of toads

and frogs (including California red-legged

frogs), fish, fish eggs, and earthworms. The

species’ range has been greatly reduced by

housing and urban development, and by water

control projects that reduce summer flows.

The introduction of non-native predators such

as bullfrogs and crayfish may have had

additional impacts.

San Francisco garter snake. The San

Francisco garter snake’s (Thamnophis sirtalis

tetrataenia) preferred habitat is densely

vegetated ponds that are located near open

hillsides or levees. Hillsides and levees are

also used by the snake for basking, feeding,

and cover (e.g., rodent burrows). Threats to

the San Francisco garter snake include loss of

habitat from agricultural, commercial, and

urban development. The decline of the

California red-legged frog (an important prey

species of the San Francisco garter snake) and

the introduction of bullfrogs into San

Francisco garter snake habitat are additional

threats (S. Larsen pers. comm. 1998).

Currently, this species is found in only a few

localities in San Francisco and San Mateo

Counties.

Western pond turtle. The western pond turtle

(Clemmys marmorata) is currently divided

into two subspecies: the northwestern pond

turtle (Clemmys marmorata marmorata),

which occurs from the vicinity of the

American River in California northward to

the lower Columbia River (OregonWashington), and the southwestern pond

turtle (Clemmys marmorata pallida), found in

coastal drainages from the vicinity of

Monterey, California south to northwestern

Baja California, Mexico. There is an

intergrade zone south of the American River

and north of Monterey ( Stebbins 1985).

Western pond turtles are habitat generalists

and occur in a wide variety of permanent and

intermittent aquatic habitats (Holland 1991).

In streams and rivers, turtles generally avoid

fast-moving and shallow waters and are

concentrated in pools and backwater areas.

Turtles are uncommon in heavily shaded

areas and prefer openings in the streamside

canopy that provide sufficient sunlight for

basking.

Threats to the turtles include introduced and

native predators, habitat alteration,

urbanization, poaching, historic commercial

exploitation, water pollution, and disease.

Excessive grazing activities in riparian areas

adversely impact turtle populations by

collapsing undercut banks used as shelter, and
42 Recovery Plan for the California Red-legged Frog

by consuming emergent vegetation used as

habitat by hatchling and first-year turtles

(Holland 1991).

Tidewater goby. Tidewater gobies

(Eucyclogobius newberryi) inhabit sandy and

silty bottoms of lagoons, shallow bays, and

estuaries. The tidewater goby ranged from

Lake Earl, Del Norte County south to Agua

Hedionda Creek, Carlsbad, San Diego County

(Irwin and Soltz 1984). They are common in

San Luis Obispo and Santa Barbara County

streams (Moyle 1976, Swift et al. 1989)

where California red-legged frogs are also

abundant. Threats include coastal

development, dredging of coastal waterways,

coastal road construction, and upstream

diversions (U.S. Fish and Wildlife Service

1994e).

Unarmored threespine stickleback.

Unarmored threespine sticklebacks

(Gasterosteus aculeatus williamsoni) are

small fish measuring up to 60 millimeters (2

inches). They inhabit slow moving reaches or

quiet water microhabitats of streams and

rivers. Favorable habitats usually are shaded

by dense and abundant vegetation, but in

more open reaches, algal mats may provide

refuge for the species. Unarmored threespine

sticklebacks reproduce throughout the year

with a minimum of breeding activity occurring from October to January. Historically,

they were distributed throughout southern

California but are now restricted to San

Antonio and Cañada Honda Creeks on

Vandenberg Air Force Base, in Santa Barbara

County, the upper Santa Clara River and its

tributaries in Los Angeles and Ventura

Counties, Shay Creek in San Bernardino

County, and San Felipe Creek in San Diego

County. The range overlaps with California

red-legged frogs in the central coast, particularly in Santa Barbara County. Competition

with non-native fish, interbreeding with other

subspecies of sticklebacks, and loss of habitat

to urbanization are factors associated with its

decline.

Coho salmon. The general biology of coho

salmon (Oncorhynchus kisutch) is described

in detail in McMahon (1983), Hassler (1987),

and Sandercock (1991). The coho salmon is

an

anadromous

species; coho salmon

generally return to their natal streams to

spawn after spending 2 years in the ocean.

The spawning migrations begin after heavy

late-fall or winter rains breach the sandbars at

the mouth of coastal streams, allowing the

fish to move into them. Spawning occurs in

small to medium-sized gravel at well-aerated

sites, typically near the head of a riffle

(Moyle 1976). These streams have summer

temperatures seldom exceeding 21 degrees

Celsius (70 degrees Fahrenheit). Emergent fry

use shallow near-shore areas, whereas

optimal habitat conditions for juveniles and

sub-adults seem to be deep pools created by

rootwads and boulders in heavily shaded

stream sections (U.S. Fish and Wildlife

Service 1996a). The distribution and habitat

of coho juveniles partially overlaps with that

of the California red-legged frog.

Because of dramatic declines in population

numbers, the National Marine Fisheries

Service was petitioned to list this species

coast-wide. Several runs were listed along the

central California coast and include regions

occupied by California red-legged frogs.

Causes of coho salmon declines in California

include incompatible land-use practices such

as logging and urbanization, loss of wild

stocks, introduced diseases, over harvesting,

and climatic changes.

Steelhead trout. Steelhead trout

(Oncorhynchus mykiss) are anadromous

rainbow trout; adult steelhead typically spawn

in gravel riffles in the spring, from February

to June. Optimum temperatures for growth

range from 13 to 21 degrees Celsius (55 to 70

degrees Fahrenheit) (Moyle 1976). Steelhead

fry reside in near-shore areas. Steelhead

juveniles tend to use riffles and pool margins,

potentially overlapping with California redlegged frog tadpoles.

The National Marine Fisheries Service was

petitioned to list this species coast-wide.

Steelhead trout is federally listed as

threatened, along the northern, central, and

south-central California coast, and listed as
Recovery Plan for the California Red-legged Frog 43

endangered in southern California and the

Central Valley.

Tricolored blackbird. Tricolored blackbirds

(Agelaius tricolor) are colonial passerines

that require several habitat components for

suitable breeding colony sites. These include

open accessible water, a protected nesting

substrate, and suitable foraging space within a

few kilometers (approximately 2 miles) of the

nesting colony (Beedy and Hamilton 1997).

Most breeding colonies are in freshwater

marshes dominated by tules (Scirpus sp.) and

cattails, some use willows (Salix spp.),

blackberries (Rubus sp.), thistles (Cirsium

and Centaurea spp.), or nettles (Urtica sp.)

(Neff 1937). Results from a statewide 1997

survey for tricolored blackbirds, coordinated

by the California Department of Fish and

Game, indicate that the population numbers

of tricolored blackbirds declined by about 37

percent compared to results of a 1994 survey.

The greatest declines occurred in Sacramento,

Fresno, Kern, and Merced Counties (Beedy

and Hamilton 1997). Threats to the tricolored

blackbird include nest failure due to

predation, habitat loss and alteration,

contaminants, and pollution. The current

ranges of the tricolored blackbird and the

California red-legged frog overlap in

Alameda, Santa Clara, Monterey, San Luis

Obispo, and Merced Counties.

Little willow flycatcher. This subspecies

(Empidonax traillii brewsteri) is

distinguished from the southwestern willow

flycatcher (Empidonax traillii extimus)

primarily by subtle differences in color,

morphology and song (Unitt 1987). The

breeding range of the little willow flycatcher

extends from central/coastal California north

through western Oregon and Washington to

Vancouver Island, Canada. The range of the

little willow flycatcher overlaps with portions

of the current and historic range of the

California red-legged frog (i.e., Coast range

and Sierra Nevada foothills). The little willow

flycatcher uses similar habitat components of

the riparian corridor as the southwestern

willow flycatcher and is threatened by similar

factors including brood parasitism, grazing,

and loss of riparian habitat.

Southwestern willow flycatcher. The

southwestern willow flycatcher (Empidonax

traillii extimus) is a small bird, with a

grayish-green back and wings, whitish throat,

light grey-olive breast, and pale yellowish

belly. The range includes southern California,

Arizona, New Mexico, and portions of

Nevada, Utah, and western Texas (Unitt

1987, Tibbitts et al. 1994). It occurs in

riparian habitats along rivers, streams or other

wetlands, where dense growth of willows,

tamarisk, or other riparian plants are present,

often with a scattered overstory of

cottonwood (Populus spp.). The southwestern

willow flycatcher has experienced extensive

loss and modification of habitat (in both

breeding habitat in North America and

wintering habitat in Mexico and Central

America) and is also endangered by brood

parasitism by the brown-headed cowbird

(Molothrus ater). Several populations occur

within the current and historic range of the

California red-legged frog including

populations located on the Santa Margarita,

Santa Ynez, Santa Ana, San Luis Rey, and

Kern Rivers (U.S. Fish and Wildlife Service

1995).

Saltmarsh common yellowthroat. The

saltmarsh common yellowthroat (Geothlypis

trichas sinuosa) is a small marsh dwelling

warbler of the subfamily Parulinae. It is also

referred to as the San Francisco common

yellowthroat. Saltmarsh yellowthroats nest in

a variety of habitats. In a study conducted by

the San Francisco Bird Observatory (Hobson

et al. 1986), yellowthroat nesting territories

were observed in five habitat types including

brackish marsh, salt marsh, riparian woodland

or swamp, freshwater marsh, and upland/or

grassland. Yellowthroats frequently use

borders between various plant communities

and territories often straddle the interface of

riparian corridors and ecotones between

freshwater or tidal marsh and the upland

vegetation of weedy fields or grassland

(Hobson et al. 1986). Extensive changes have

occurred in San Francisco Bay since the turn

of the century that have resulted in reductions

in the extent and suitability of habitat for the

yellowthroat. The remaining habitat is under

threat from a number of sources which range

from land development to flood control
44 Recovery Plan for the California Red-legged Frog

actions. Surveys conducted in 1977, 1985

(Hobson et al. 1986), and 1996 (Nur et al.

1997) for the saltmarsh common

yellowthroat, indicate that the species is

present in the following counties: Sonoma,

Napa, Solano, Marin, San Francisco, Contra

Costa, Alameda, San Mateo, and Santa Clara.

Saltmarsh common yellowthroat occurrences

overlap with the California red-legged frog in

riparian and freshwater marsh habitats.

Least Bell’s vireo. The least Bell’s vireo

(Vireo bellii pusillus) is a small gray,

migratory passerine. It was once widespread

and abundant as a nesting species throughout

the Central Valley and other low-elevation

riverine valleys. Its historic range extended

from interior northern California (near Red

Bluff, Tehama County) to northwestern Baja

California, Mexico. It is assumed to be

extirpated from the Sacramento and San

Joaquin valleys, and its breeding range seems

to be restricted to Inyo, Santa Barbara,

Ventura, Los Angeles, San Bernardino, San

Diego, and Riverside Counties (Goldwasser

1978). Recent evidence of breeding has been

documented in San Benito and Monterey

Counties (L. Hays pers. comm. 1998) and

Santa Clara County (D. Padley pers. comm.

1998). The vireo’s range overlaps with the

California red-legged frog in Santa Barbara

County (e.g., Santa Ynez River), Ventura

County (e.g., Santa Clara River near Lake

Piru), and San Benito, Monterey, and Santa

Clara Counties. The vireo primarily inhabits

dense, willow-dominated riparian habitats

with lush understory vegetation. It is

threatened by loss of habitat, grazing of

riparian corridors, and brood parasitism by

the brown-headed cowbird (U.S. Fish and

Wildlife Service 1998).

Marsh sandwort. The marsh sandwort

(Arenaria paludicola) is a herbaceous green

perennial often supported by surrounding

vegetation, with angled or grooved stems.

The species blooms from May to August.

Flowers are small, white, and borne singly on

long stalks. Only two of California’s seven

historical populations of marsh sandwort are

know to exist today, near the southern San

Luis Obispo County coast at Black Lake

Canyon on the Nipomo Mesa and at Oso

Flaco Lake further south. Recently, another

occurrence of the Arenaria paludicola was

found in MacKerricher State Park,

Mendocino County. Marsh sandwort is found

in freshwater marshes. Immediate threats to

its survival include habitat degradation or

destruction and competition with exotic

species for light, water, nutrients, and space.

Other threats to the survival of the species

may be related to biological and genetic

factors and the occurrence of sudden

disastrous events.

Gambel’s watercress. The Gambel’s

watercress (Rorippa gambellii) is a member

of the mustard family (Brassicaceae) and is

an herbaceous perennial that produces dense

white flowers from April to June. This plant

is found in freshwater or brackish marsh

habitats at the margins of lakes or along slowflowing streams. Three known populations

occur in San Luis Obispo County at Black

Lake Canyon, Oso Flaco Lake, and lands

owned by the California Department of Parks

and Recreation (Pismo Beach State Vehicle

Recreation Area). This species faces threats

from alteration of hydrology, competition

with encroaching eucalyptus trees

(Eucalyptus globulus), urban

development, and stochastic

extinction due to the small

number of individuals and

populations that remain.
45

II. Recovery

A. RECOVERY OBJECTIVES AND STRATEGIES

The objective of this recovery plan is to delist

the California red-legged frog. Eight recovery

units have been established for the California

red-legged frog. Because of the varied status

of this subspecies and differing levels of

threats throughout its range (Table 3),

recovery strategies differ per recovery unit to

best meet the goal of delisting the species.

For example, in areas where California redlegged frog populations appear to be stable,

recovery strategies will be to protect existing

population numbers, whereas in areas where

frogs have been extirpated or are declining,

strategies will be to stabilize, increase,

augment, or reestablish populations.

Differences within recovery units are also

evident. Thus, recovery actions such as

implementing land use guidelines are not

expected to be applied across-the-board

within each recovery unit or throughout the

range of the frog; recovery implementation

will be focused within suitable habitat in each

recovery unit. Recovery unit boundaries and a

detailed description of recovery units follows

in section C of this Recovery section (Figure

11).

Overall, the strategy for recovery of the

California red-legged frog will involve: 1)

protecting existing populations by reducing

threats; 2) restoring and creating habitat that

will be protected and managed in perpetuity;

3) surveying and monitoring populations and

conducting research on the biology of and

threats to the subspecies; and 4) reestablishing populations of the subspecies within its

historic range.

Protection of existing populations will occur

through preservation (e.g., fee title acquisition, conservation easements, conservation

agreements) and management of occupied

drainages and cor areas. Reduction of threats

will focus on reversing the apparent loss and

Table 3. Threats to California red-legged frogs and their recovery status per recovery unit.

Recovery

 Recovery Unit Threats Status

 1. Sierra Nevada Foothills and Central Valley Ag, Li, Mi, Nn, Re, Ti, Ur,Wa Low

 2. North Coast Range Foothills and Western Sacramento River Valley Ag, Li, Nn, Ti, Ur Low

 3. North Coast and North San Francisco Bay Li, Nn, Ur, Wa High

 4. South and East San Francisco Bay Li, Nn, Ur, Wa, High

 5. Central Coast Ag, Li, Mi, Nn, Re, Ti, Ur, Wa High

 6. Diablo Range and Salinas Valley Ag, Li, Mi, Nn, Re, Ur, Wa Med

 7. Northern Transverse Range and Tehachapi Mountains Ag, Mi, Nn, Re, Wa, High

 8. Southern Transverse and Peninsular Ranges Ag, Li, Mi, Nn, Re, Ur,Wa Low

Threats: Ag=Agriculture, Nn=Non-native species, Li=Livestock (cattle grazing and/or dairies), Mining=Mi,

Re=Recreation, Ti=Timber, Ur=Urbanization, Wa=Water Management/Diversions/Reservoirs

Recovery Status:

Low: Few existing populations, high levels of threats and, in general, medium habitat suitability

Med: Numerous existing populations, some areas of medium habitat suitability, high levels of threats

High: Many existing populations, many areas of high habitat suitability, low to high levels of threats
46 Recovery Plan for the California Red-legged Frog

degradation of habitat by improving the

quality and connectivity of aquatic and

upland habitats within core watersheds.

Efforts are needed to decrease the impacts of

urbanization and the conditions that allow the

proliferation of non-native aquatic predators.

In addition, research is necessary to develop

solutions to the pollution which may be

detrimental to all life stages of the California

red-legged frog.

Habitat needed by the California red-legged

frog for reproduction, development, and

survival is dependent on the dynamic nature

of aquatic systems (riparian, sag ponds,

springs, lagoons, marshes, vernal pools, etc.).

Therefore, recovery will be achieved when

breeding habitats are created and maintained

naturally by fluctuating hydrological,

geological, and ecological processes. In

regulated bodies of water where natural

processes are interrupted, water management

regimes and land use practices appropriate to

maintain habitat suitability must be

demonstrated over the long term, prior to

delisting. Habitat protection and restoration

will be achieved by controlling non-native

predators, managing flows in ways that are

beneficial for frogs, controlling erosion and

sedimentation, replanting wetland vegetation,

and increasing connectivity of habitat

between known breeding areas. One

component of the recovery strategy will be to

encourage private landowners and public land

managers that have existing man-made ponds

(e.g., stock ponds) to modify pond structure

and management such that they best provide

breeding habitat for frogs. While the focus of

recovery is on natural, dynamic aquatic

systems and healthy uplands, in some

recovery units (e.g., south and east San

Francisco Bay, Diablo Range), the

importance of artificial pond management is

expected to be high. These artificial ponds

may prove to be critical in years where

conditions in natural aquatic systems are

unsuitable by providing alternative habitat for

dispersing juveniles and adults. In both

natural and artificial habitats, protection via

conservation easements, acquisition, or other

mechanisms is expected to provide long-term

benefits to the species.

Upon completion of the tasks aimed at

removing threats and increasing habitat

protection, recovery is expected to occur

through natural recolonization and population

expansion. This may be highly unlikely,

however, in portions of the historic range

where frogs are absent or nearly absent. In

these areas, determining the reasons for local

or regional extirpation will be necessary

followed by implementation of the

appropriate recovery tasks to increase

suitability and reduce threats. Upon

achieving the necessary habitat conditions,

pilot re-establishment programs may help to

increase the current range and recover the

red-legged frog. Re-establishment is not

expected to be implemented in recovery units

where California red-legged frog populations

are numerous unless large distances occur

between populations and natural dispersal/

expansion is unlikely to occur. In largely

unoccupied areas where isolated, unstable

populations exist, population augmentation

(i.e. adding individuals to the population)

may be appropriate.

B. RECOVERY CRITERIA

Delisting of this species will be considered

when:

1) Suitable habitats within all core areas

(described in section D below) are protected

and/or managed for the California red-legged

frog in perpetuity, and the ecological integrity

(e.g., water quality, uplands condition,

hydrology) of these areas is not threatened by

adverse anthropogenic habitat modification

(including indirect effects of upstream/

downstream land uses);

2) Existing populations, throughout the

range, are stable (i.e., reproductive rates

allow for long term viability without human

intervention). Because population numbers

do not necessarily indicate stability (i.e., a

population may have large numbers of

individuals one year then decline

precipitously as documented at the Santa

Rosa Plateau locality), long term evidence of

successful reproduction (e.g., presence of

juveniles) and survivorship into different age
Recovery Plan for the California Red-legged Frog 47

classes provides a better indication of

stability, persistence, and population

resilience. Therefore, population status will

be documented through establishment and

implementation of a scientifically acceptable

population monitoring program for at least a

15-year period (four to five generations) that

includes an average precipitation cycle (a

period when annual rainfall includes average

to 35 percent above-average through greater

than 35 percent below-average and back to

average or greater; the direction of change is

unimportant in this criterion).

3) Populations are geographically distributed

in a manner that allows for the continued

existence of viable metapopulations despite

fluctuations in the status of individual

subpopulations (i.e., when populations are

stable at each core area);

4) The subspecies is successfully

reestablished in portions of its historic range

such that at least one reestablished population

is stable/increasing in each core area where

frogs are currently absent; and

5) The amount of additional habitat needed

for population connectivity, recolonization,

and dispersal has been determined, protected,

and managed for the California red-legged

frog. There will be varying scales of

connectivity needed including at the level of a

local population (i.e., connectivity of habitat

within a drainage) up to the needs of a

metapopulation (many linked drainages over

large regions such as recovery units). This

will provide dispersal opportunities for

population viability, genetic exchange, and

recolonization.

Criteria for delisting will be revised and

quantified as additional information is

provided by research projects and monitoring

programs. If it is determined through research

that distinct vertebrate population segments

exist, delisting may be considered

independently for each distinct vertebrate

population (see section C below). If recovery

criteria are met, rangewide delisting of the

California red-legged frog could occur by

2025.

The five listing criteria under section 4(a)(1)

describe the reasons for decline and threats

that led to the listing of the California redlegged frog. These are described, in detail, in

Section F, Reasons for Decline and Threats to

Survival in Section I, Introduction. The above

recovery criteria relate to these listing factors

in that they will reverse the negative effects of

these threats and result in recovery of this

species. Each recovery criterion (delisting

criterion) can be met via implementation of

the recommended recovery tasks as described

in the Outline of Recovery Actions in Section

III (see Table 4). Land use guidelines are

provided in the Outline of Recovery Actions

that should be used when developing

watershed management and protection plans

that are required of Tasks 1.0, 2.0, and 3.0;

these guidelines will also be useful in

implementing many other tasks. General

recovery goals that address metapopulation

viability, dispersal, and reestablishment

within the historic range will provide the

California red-legged frog with the stability

needed to survive fluctuating environmental

conditions and thus reduce susceptibility to

manmade and natural effects (e.g., drought,

invasions of predators).

C. RECOVERY UNITS

Initial Recovery Units. In the May 23, 1996,

Final Rule listing the California red-legged

frog as federally threatened, the following

recovery units were established:

1. The western foothills and Sierra Nevada

foothills to approximately 1,500 meters

(5,000 feet) in elevation in the Central Valley

hydrographic basin.

2. The Central Coast ranges from San Mateo

and Santa Clara Counties south to Ventura

and Los Angeles Counties.

3. The San Francisco Bay/Suisun Bay

hydrologic basin.

4. Southern California, south of the Tehachapi

Mountains.

5. The northern coast range in Marin and

Sonoma Counties.
48 Recovery Plan for the California Red-legged Frog

Based on conservation needs, ecology, and

distribution, the recovery units as described in

the final rule (U.S. Fish and Wildlife Service

1996a) were revised, to facilitate recovery of

the California red-legged frog (Figure 11).

The eight recovery units are essential to the

recovery of this subspecies; throughout

implementation of this recovery plan and in

other planning efforts (e.g., section 7

consultations pursuant to the Endangered

Species Act), the status of the frog will be

considered within the smaller scale of

recovery units as opposed to the statewide

range, and therefore, will benefit from a

region-specific approach to conservation. As

the recovery units reflect areas with similar

conservation needs and population statuses,

appropriate means of implementation and

monitoring of the recovery plan will be

facilitated. Individual recovery units of the

California red-legged frog may be considered

for delisting if research shows that they may

be regarded as distinct vertebrate population

segments. Distinct population segments are

Table 4. Recovery Goals and Tasks Aimed at Reducing or Eliminating Threats

Listing Criterion Recovery Criterion Tasks Within Recovery Plan

and Threats (Delisting Criterion) that Address Threat Reduction

or Elimination

1. Present or threatened destruction, modification, or curtailment of habitat or range

Curtailment of Range 4 10.1, 10.2, 10.2.1, 10.3.2, 10.3.3

Urbanization 1 1.0, 2.0, 3.0, 4.0, 5.0, 6.1

Agriculture 1 1.0, 2.0, 4.0, 11.7

Water Management 1 1.0, 2.0, 3.0, 4.0, 7.0

Flood Control 1 1.0, 2.0, 3.0, 4.0, 5.0

Mining 1 1.0, 7.0

Grazing 1 1.0, 11.13, 11.13.2

Recreation 1 1.0, 4.0

Timber 1 1.0

2. Overutilization for commercial, recreational, scientific, or education purposes

Exploitation 2 12.1

Scientific Take 2 9.1, 9.2, 11.1

3. Disease and Predation

Disease 3 9.1, 9.2

Predation by Introduced Species 1,3 1.0, 11.8, 11.9, 11.15

Predation by Native Species 1,3 1.0, 1.3

4. Inadaquacy of existing regulatory mechanisms

Section 7(a)(2) of ESA 1,3,5 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9

5. Other natural or manmade factors

Drought 3,4 4.0, 11.3.2, 11.3.3, 11.5, 11.6

Contaminants 1 1.0, 4.0, 5.0, 7.0, 8.0, 11.7
Recovery Plan for the California Red-legged Frog 49

defined by us for the purposes of listing,

delisting and reclassification of vertebrate

fish or wildlife taxa. To be determined a

distinct population segment, the portion of the

taxon under consideration must be ‘discrete’

and ‘significant’ in relation to the remainder

of the taxon. A portion of a taxon may be

considered discrete if it is separated from

other portions of the taxon by geographic,

genetic, physiological, behavioral, or

ecological factors. The portion of the taxon is

considered ‘significant’ if it occupies a setting

that is unusual or unique for the taxon, if its

loss would result in an appreciable gap in the

range of the taxon, or if it is substantially

different genetically from the rest of the

taxon. If a population segment is both discrete

and significant, then it qualifies as a distinct

population segment, and it may be considered

independently for listing or delisting (U.S.

Fish and Wildlife Service 1996e). The eight

recovery units identified in this plan are

delineated by watershed boundaries as

defined by U.S. Geological Survey

hydrologic units and the limits of the range of

the California red-legged frog (i.e., 1,500-

meter [5,000-foot] elevation). The following

lists the U.S. Geological Survey hydrologic

units included in each recovery unit.

Revised Recovery Units.

1. Sierra Nevada Foothills and Central

Valley. The eastern boundary is the 1,500-

meter (5,000-foot) elevation. Watersheds

include: Sacramento Headwaters, McCloud,

Lower Pit, Sacramento-Lower Cow-Lower

Clear, Upper Cow-Battle, Mill-Big Chico,

Upper Butte, North Fork Feather, East Branch

North Fork Feather, Middle Fork Feather,

Honcut Headwaters, Upper Yuba, Upper

Bear, Upper Coon-Upper Auburn, North Fork

American, South Fork American, Lower

Butte, Lower Feather, Lower Yuba, Lower

Bear, Lower American, Upper Kern, South

Fork Kern, Upper Poso, Upper Deer-Upper

White, Upper Tule, Upper Kaweah, Mill,

Upper Dry, Upper King, Tulare-Buena Vista

Lakes, Middle San Joaquin-Lower

Chowchilla, Middle San Joaquin-Lower

Merced-Lower Stanislaus, Upper San

Joaquin, Upper Chowchilla-Upper Fresno,

Upper Merced, Upper Tuolumne, Upper

Stanislaus, Upper Calaveras, Lower

Cosumnes-Lower Mokelumne, Lower

Calaveras-Mormon Slough, Upper

Mokelumne, and Upper Cosumnes.

2. North Coast Range Foothills and Western

Sacramento River Valley. Watersheds

include: Lower Cottonwood, SacramentoLower Thomes, Lower Sacramento, Lower

Cache, Sacramento-Upper Clear, Cottonwood

Headwaters, Upper Elder-Upper Thomes,

Upper Stony, Sacramento-Stone Corral,

Upper Cache, and Upper Putah.

3. North Coast and North San Francisco

Bay. Watersheds include: Tomales-Drakes

Bays, San Pablo Bay (partial), and Suisun

Bay (partial).

4. South and East San Francisco Bay.

Watersheds include: Suisun Bay (partial), San

Pablo Bay (partial), San Francisco Coastal

South (partial), San Francisco Bay, Coyote,

and San Joaquin Delta.

5. Central Coast. Watersheds include: San

Francisco Coastal South (partial), San

Lorenzo-Soquel, Central Coastal, and

Carmel.

6. Diablo Range and Salinas Valley.

Watersheds include: Panoche-San Luis

Reservoir, Pajaro, Upper Gatos, Estrella,

Tulare-Buena Vista Lakes (partial), Carrizo

Plain, Alisal-Elkhorn Sloughs, and Salinas.

7. Northern Transverse Ranges and

Tehachapi Mountains. Watersheds include:

Middle Kern-Upper Tehachapi-Grapevine,

Santa Maria, Santa Ynez, Cuyama, San

Antonio, Santa Barbara, Ventura, Santa

Clara, and Antelope-Fremont Valleys

(partial).

8. Southern Transverse and Peninsular

Ranges. Watersheds include: Calleguas,

Santa Monica Bay, Los Angeles, San Gabriel,

Antelope-Fremont Valleys (partial), Santa

Ana, San Jacinto, Seal Beach, Newport Bay,

Aliso-San Onofre, Santa Margarita, San Luis

Rey, San Diego, Cottonwood-Tijuana,

Whitewater River, San Felipe Creek, and

Salton Sea (partial).
50 Recovery Plan for the California Red-legged Frog

D. CORE AREAS AND PRIORITY

WATERSHEDS FOR FOCUSED RECOVERY

EFFORTS

Core Areas:

While a goal of the recovery plan is to protect

the long-term viability of all existing populations within each recovery unit, several areas

have been identified as core areas where

recovery actions will be focused (Figure 12

and Appendix C). The core areas, which are

distributed throughout portions of the historic

and current range, represent a system of areas

that, when protected and managed for

California red-legged frogs, will allow for

long-term viability of existing populations

and reestablishment of populations within the

historic range. The core areas were chosen for

focused recovery either because they represent viable populations (possibly even source

populations for larger metapopulations), or

because the locations will contribute to the

connectivity of habitat and thus increase

dispersal opportunities between populations.

Preservation and enhancement of each core

area is important to maintain and expand the

distribution of California red-legged frog

populations rangewide. Core areas will

require long-term protection and management

so that existing and reestablished populations

remain viable. Recovery and delisting will be

facilitated by meeting recovery criteria in all

core areas.

In many recovery units, core areas represent

areas of high California red-legged frog

densities (e.g., Pescadero Marsh); some core

areas, however, do not currently support the

California red-legged frog (e.g., most Sierra

Nevada and southern California watersheds).

Core areas located in the historic range

represent areas where restoration of habitat is

most feasible, where pilot reestablishment

efforts are most likely to be successful, and

where natural recolonization is expected.

Inclusion of the core areas in the historic

range will prevent further range collapse (i.e.,

prevent the California red-legged frog from

becoming merely a distinct vertebrate

population segment along the coast from

Point Reyes south to Santa Barbara County).

The core areas in the historic range also

represent important elements of the historic

ecosystems used by the California red-legged

frog (i.e., inclusion of non-coastal

ecosystems). These unoccupied areas will

require varying degrees of rehabilitation with

the expectation of future recolonization or

reestablishment efforts when habitat

suitability has been restored.

While core areas are mapped in Figure 12, the

entire area described as a core area may not

represent suitable California red-legged frog

habitat. Habitats within core areas should be

assessed for suitability. This is especially

important in areas between the elevations of

1,050 and 1,500 meters (3,500 and 5,000

feet). At these elevations, known localities are

rare and suitable habitat appears to be less

abundant. In addition to elevational

constraints, many portions of the mapped

core areas are agricultural lands and urban

developments which, in most cases, will be

considered unsuitable and excluded from the

recovery efforts. Recovery goals should be

implemented only where suitable or

potentially suitable habitat is present.

Results of monitoring and habitat

management will reveal, in time, whether

core areas will provide suitable habitat. If

selected drainages are unlikely to support

frogs, alternative core areas will be identified.

In recovery units where the status of the

California red-legged frog is largely unknown

(e.g., Sierra Nevada foothills, North Coast

Range), additional or replacement core areas

may be identified to best protect existing

populations and focus recovery efforts after

survey results are obtained. This will provide

flexibility in implementing the recovery plan

by adjusting the locations and numbers of

core areas if they are not providing suitable

habitat after restoration attempts.

Because core areas typically include entire

watersheds and thus include both public and

private lands, cooperative agreements among

public land managers, local planning

departments, resource conservation districts,

and private landowners will be relied upon to

ensure that these areas are managed to

support the California red-legged frog.

Core areas include many watersheds within
51
Recovery Plan for the California Red-legged Frog 53

the boundaries. They were mapped by

selecting the appropriate Hydrologic SubAreas per the California Watershed Map

(CALWATER version 2.2).

Core areas were selected based on several

criteria as described below. Table 5 lists

which selection criteria applies to each core

area and demonstrates the importance of each

core area to recovery of the California redlegged frog.

The delineation of core areas, however, will

not limit the scope of recovery plan

implementation. Areas of suitable or

potentially suitable habitat outside designated

core areas (particularly priority 2 and 3

watersheds) are also expected to be examined

for possible recovery plan implementation

and managed according to appropriate landuse guidelines.

Priority 2 Watersheds:

Many watersheds that are not listed as core

areas currently support the California redlegged frog. These watersheds are in need of

conservation and appropriate management

(conservation needs vary per watershed) and

are considered priority 2 watersheds. The

number of priority 2 watersheds will most

likely change according to the status of the

frog; as more localities are identified, these

should be included as priority 2 watersheds

and managed according to the appropriate

recovery strategies for this species. Protection

of priority 2 watersheds will provide the

necessary habitat connectivity between core

areas and is an important contribution to the

recovery of the California red-legged frog

throughout its range.

Priority 3 Watersheds:

Priority 3 watersheds are areas that historically harbored California red-legged frogs.

These areas will need (in most cases)

extensive rehabilitation prior to recolonization or reestablishment. These are considered

as priority 3 because in these watersheds, the

likelihood of successful recovery is less than

in core areas and priority 2 watersheds.

However, with intensive efforts and public

support, conservation of habitat in these

watersheds is possible and may contribute to

Selection Criteria for Core Areas

Occupied. Some core areas were selected because they had one or

more occupied drainages. Drainages are considered currently

occupied if there are frog sightings from 1985 or later. Historic and

current distribution information for watersheds that are included in

core areas can be found in Section C. Historic and Current

Distribution and by referring to the Natural Diversity Database

which is maintained by the California Department of Fish and

Game (Natural Diversity Database 2001). Extant populations found

on the periphery of the current range were included as core areas.

Historically occupied. Many watersheds are currently unoccupied

but appear to be important to recovery due to the numerous historic

records that exist for these areas. Restoring habitat in historically

occupied watersheds and possibly reestablishing California redlegged frogs in the appropriate, restored areas is important to

recovery as this will restore the distribution of the species to the

historic range and reverse the observed range collapse and

concentration of populations along the Pacific coast.

Source populations. Based on discussions with California redlegged frog experts and analyses of survey data, watersheds were

chosen as core areas if data suggested that the watershed harbored a

source population which provide colonizers to nearby areas,

showed reproductive success over an extended period of time (i.e.,

frogs and young present since 1985 or longer) and appeared to be

stable in population size or growing.

Potential for Reestablishment. As mentioned before, some core

areas are unoccupied but appear to be restorable and/or represent

important segments of the historic range. Some unoccupied

watersheds that are listed as core areas represent areas in which

reestablishment efforts are considered most likely to succeed.

Connectivity. Some core areas, whether occupied or unoccupied,

provide the necessary connectivity between known populations.

Connectivity is important in maintaining viable metapopulations

throughout the range of the species.

Other. As noted above, some core areas were chosen despite being

currently unoccupied. In some of these cases, particular watersheds

appear to be highly restorable. For example, some watersheds have

been listed as having high ecological integrity and are classified as

an Aquatic Diversity Management Area by Moyle et al. (1996).

Aquatic Diversity Management Areas represent watersheds that

have, among other characteristics, high values for aquatic

biodiversity, are dominated by native aquatic species, and have

terrestrial and riparian ecosystems that are in fairly good condition.

Extant and extirpated areas were included if they represent the

historic distribution of the species.
54 Recovery Plan for the California Red-legged Frog

Table 5. Selection criteria for core areas and importance of core areas for recovery.

Core Area Selection Criteria

Currently

Occupied

(post-1985)

Historically

Occupied

Source

Population

Potential for

Reestablishment or

Augmentation

Connectivity Other

Feather River x x x

Yuba River - South 

Fork Feather

x Indian Creek listed as Aquatic 

Diversity Management Area 

because it contains nearly 

pristine habitat, threatened 

amphibians, and dominated by 

native fish

Middle Fork American x x x

Cosumnes River-South 

Fork American River

x x x Rock Creek listed as an Aquatic 

Diversity Management Area 

because native frogs and fish are 

present, Cosumnes River is 

focus of restoration effort led by 

The Nature Conservancy

South Fork Calaveras x x Extirpated but represents 

historic range

Tuolumne River x x Extirpated but represents 

historic range

Piney Creek x x Extirpated but represents 

historic range

Cottonwood Creek x x Extant on periphery of range

Putah Creek-Cache 

Creek

x xx

Tributaries to Lake 

Berryessa

xxx Extant on periphery of range

Upper Sonoma Creek x x

Petaluma Creek-Sonoma 

Creek

xxx

Point Reyes Peninsula x x

Belvedere Lagoon x x x

Fagan-Jameson CanyonLower Napa Riverxxx

East San Francisco Bay x x x

Santa Clara Valley x x x

South San Francisco 

Bay

xxx
Recovery Plan for the California Red-legged Frog 55

Table 5 (continued). Selection criteria for core areas and importance of core areas for recovery.

Core Area Selection Criteria

Currently

Occupied

(post-1985)

Historically

Occupied

Source

Population

Potential for

Reestablishment or

Augmentation

Connectivity Other

Salinas River-Pajaro 

River

xxx

Carmel River-Santa 

Lucia l

xxx

Gablan Range x x x

Estero Bay x x x

Arroyo Grande Creek x x

Santa Maria - Santa 

Ynez River

xxx

Sisquoc River x x x

Ventura River - Santa 

Clara River

x x

Santa Monica BayVentura Coastal Streamsxxx Extant on periphery of range

Estrella River x x

San Gabriel Mountains x x

Mojave River x x Extirpated but represents 

historic range

Santa Ana Mountain x x Extirpated but represents 

historic range

Santa Rosa Plateau x x Extant on periphery of range

San Luis Rey x x x Extirpated but represents 

historic range

Sweetwater River x x x Extirpated but represents 

historic range

Laguna Mountain x x x Extirpated but represents 

historic range
56 Recovery Plan for the California Red-legged Frog

Critical Habitat

Critical habitat affects Federal agencies by requiring them to evaluate the effects that any

activities they fund, authorize, or carry out may have on listed species. Agencies are

required to ensure that such activities are not likely to jeopardize the survival of a listed

species or adversely modify (e.g., damage or destroy) its critical habitat. By consulting

with us, Federal agencies can usually minimize or avoid any potential conflicts; activities

have almost always been allowed to proceed in some form. It should be noted that critical

habitat designation does not create a wilderness area, preserve, or wildlife refuge. It

applies only to activities sponsored at least in part by Federal agencies. Such federallypermitted land uses as grazing and recreation may take place if they do not adversely

modify critical habitat. Designation of critical habitat does not constitute a land

management plan nor does it signal any intent of the government to acquire or control the

land. Therefore, if there is no Federal involvement (e.g., Federal permit, funding, or

license), activities of a private landowner, such a farming, grazing or constructing a home,

generally are not affected by a critical habitat designation, even if the landowners’

property is within the geographical boundaries of critical habitat. Without a Federal

connection to a proposed action, designation of critical habitat does not require that

landowners of State or other non-Federal lands do anything more than they would

otherwise do to avoid take under provisions of section 9 and 10 of the Endangered

Species Act.

the overall distribution and recovery of this

species.

Critical Habitat. On March 13, 2001, a final

designation of critical habitat was made for

the California red-legged frog. The critical

habitat designation has been challenged in

court; the status of the case has not been

resolved as this plan goes to press. The legal

ramifications of critical habitat designations

are described below. Approximately

1,674,582 hectares (4,140,440 acres) of land

fall within the critical habitat designation.

Specifically, aquatic and upland areas where

suitable breeding and nonbreeding habitat is

interspersed throughout the landscape and is

interconnected by unfragmented dispersal

habitat is critical habitat.

Core areas and critical habitat areas were

selected based on similar criteria. The main

criteria used for both were to capture areas: 1)

that are occupied by California red-legged

frogs, 2) where populations of California redlegged frogs appear to be source populations,

3) that provide connectivity between source

populations, and 4) that represent areas of

ecological significance. For the selection of

core areas, areas of ecological significance

include: watersheds that represent the limits

of the current and historic range and/or that

appear to be restorable and thus good sites

for reestablishment projects. Unlike the

selection of core areas, it is a requirement

that primary constituent elements be defined

for critical habitat. These primary constituent

elements are described in this recovery plan

in Section I, part G. Regulatory Protection

and Conservation Measures and are present

in all critical habitat areas and core areas.

The core areas and critical habitat areas differ

in several ways. Unlike core areas which

have no legal mandate for protection under

the Endangered Species Act and solely rely

upon voluntary implementation, the

designation of critical habitat requires

Federal agencies to consult with us regarding

any action that could destroy or adversely

modify critical habitat. Adverse modification

of critical habitat is defined as any direct or

indirect alteration that appreciably

diminishes the value of the habitat for both

the survival and recovery of the species.
Recovery Plan for the California Red-legged Frog 57

E. EFFECTS OF THE RECOVERY STRATEGY ON

ASSOCIATED SPECIES

Many of the threats facing the California redlegged frog have also resulted in declines of

other native, coexisting species. Therefore,

improved habitat conditions for co-occurring

species are expected to occur through

attainment of the recovery objectives.

Monitoring of co-occurring species is

recommended as a task of this plan, and

California red-legged frog recovery actions

that may have adverse effects on associated

sensitive species should be adjusted to reduce

impacts. However, the net effect on native

species of implementing this plan is expected

to be predominantly positive. The following

describes potential effects of recovery tasks

on specific taxa.

California freshwater shrimp. Protection

and improvement of riparian habitat will

increase vegetative cover required for

protection from predators. Control of nonnative fish and crayfish may also decrease the

occurrences of predation and thus increase

survivorship of California freshwater shrimp. Tomales asellid. The Tomales asellid relies

upon the presence of dense mats of marsh

pennywort (Hydrocotyle spp.) and submerged

decaying leaves; California red-legged frogs

have been observed utilizing marsh

pennywort as a substrate for egg mass

attachment (S. Christopher in litt. 1998).

Restoration or protection of habitat

conditions for the California red-legged frog

will result in increased streamside vegetation

and thus a source of fallen, decaying leaves,

and in some areas, mats of marsh pennywort.

Benefits for Tomales asellid are expected in

the Golden Gate National Recreation Area

and Point Reyes National Seashore where the

ranges of the species overlap.

California tiger salamander. California tiger

salamanders and California red-legged frogs

are often found coexisting in stock ponds and

other artificial impoundments in the San

Francisco Bay region. Improved management

of artificial ponds for the benefit of the

California red-legged frog is expected to

increase suitability of these habitats for tiger

salamanders and decrease the suitability of

these ponds for non-native aquatic predators.

Because California tiger salamanders often

estivate by using small mammal burrows

adjacent to waterways, care must be taken to

avoid trapping salamanders in burrows while

managing ponds for California red-legged

frogs.

Santa Cruz long-toed salamander. Removal

of non-native aquatic predators for the

California red-legged frog will benefit the

salamander where the two species overlap.

Restoration of flows to coastal sloughs will

slow saltwater intrusion and benefit this

species. In addition, management of shallow,

ephemeral, freshwater ponds will increase the

suitability of habitat for this species, while

decreasing the proliferation of non-native

aquatic predators.

Foothill yellow-legged frog and mountain

yellow-legged frog. Both of these species

have experienced population declines due to

the presence of non-native aquatic species,

particularly in the Sierra Nevada and Coast

Range foothills. Predator control and reduced

stocking of non-native fish should increase

the breeding success and survival of these

species. Further, restoration of streams and

creeks should result in water flow regimes

and vegetative cover that provide suitable

habitat for these species.

Arroyo southwestern toad. Protection and

enhancement of stream systems for the

California red-legged frog should also

provide the necessary components of arroyo

toad breeding habitat, such as shallow pools

in streams and dense riparian vegetation.

Many of the land uses that threaten the

California red-legged frog also threaten

arroyo toads. Thus, implementation of

appropriate land use guidelines and best

management practices will benefit both

species. This is particularly true if guidelines

for off-road vehicles, mining, and grazing are

implemented. Control of non-native aquatic

predators will also benefit both species. Western spadefoot toad. A large portion of

habitat restoration for California red-legged

frog recovery will involve the creation of-
58 Recovery Plan for the California Red-legged Frog

and management of- artificial ponds such as

stock ponds. Because western spadefoot toads

are associated with stockponds they may

benefit from the increased availability and

suitability of such habitat. Many areas that

are listed as core areas for protection and

management will also benefit the western

spadefoot toad. Such areas include large

portions of the south and east San Francisco

Bay and the vicinity of San Luis Reservoir.

Alameda whipsnake. Protection of large

tracts of land including uplands that connect

breeding areas for the California red-legged

frog should provide protected areas of coastal

scrub and chaparral required by the Alameda

whipsnake. Benefits to the Alameda

whipsnake will particularly be high in

Alameda and Contra Costa Counties, where

protection and management of core areas for

the California red-legged frog should result in

fairly well connected reserves of uplands and

aquatic habitats.

Two-striped garter snake and San Francisco

garter snake. One of the goals of this

recovery plan is to maintain long-term

viability and increased reproductive success

of California red-legged frogs despite natural

sources of mortality (i.e., predation by native

predators). The decline of the California redlegged frog, which is a prey species of the

both the two-striped garter snake and the San

Francisco garter snake, and the introduction

of bullfrogs into aquatic habitats are both

threats to these species. Therefore, with

implementation of this recovery plan, it is

expected that increased numbers of California

red-legged frogs will subsequently increase

the prey base for garter snakes. Habitat

restoration and predator control (e.g., the

continued control of bullfrogs at Pescadero

Marsh) will benefit both species as well as the

California red-legged frog. Further, any

measures that reduce the impacts of

urbanization (i.e., water management and

protection of undeveloped habitat areas) will

be beneficial.

Western pond turtle. Management of streams,

creeks, and natural and artificial ponds should

provide habitat enhancements for western

pond turtles. In regulated streams, restoration

of natural flow regimes will help to maintain

suitability for turtles. Control of bullfrogs and

predatory non-native fish will also benefit the

western pond turtle.

Tidewater goby. Implementation of tasks to

recover frog populations in lagoons and

coastal streams should also improve habitat

conditions for gobies. Reduction of sediments

in creek channels from bank erosion,

livestock grazing, timber harvesting, and

recreation will benefit the tidewater goby.

Unarmored threespine stickleback. Removal

of non-native aquatic predators for the

California red-legged frog will benefit the

stickleback where the two species overlap.

Restoration of habitat in slow moving stream

reaches will also benefit this species.

Salmonids. Removal of threats in streams

supporting the California red-legged frog is

expected to improve aquatic habitat

conditions for threatened runs of coho salmon

and steelhead where geographic ranges

overlap. Protection and restoration of riparian

conditions in core watersheds and drainages

harboring frog populations will moderate

extreme temperature fluctuations, reduce

sediment transport to streams, provide

terrestrial insects for food, eventually provide

in-stream woody debris and undercut banks

for cover, and create habitat conditions less

favorable to introduced predators.

Tricolored blackbird. The preservation of

ponded habitat for the California red-legged

frog with emergent vegetation and protective

buffers from urban predators (e.g., raccoons)

should greatly benefit the tricolored

blackbird, which primarily relies upon

emergent marsh habitat for breeding.

Southwestern willow flycatcher, little willow

flycatcher, and least Bell’s vireo. Care must

be taken to avoid disturbing breeding sites of

the flycatcher where tamarisk is present.

Removal of tamarisk for the benefit of the

California red-legged frog must be weighed

against any potential losses of breeding

habitat for the flycatcher. Monitoring of avian

use of tamarisk at a targeted site should

decrease the chances that negative impacts
Recovery Plan for the California Red-legged Frog 59

may result. Overall, increased streamside

habitat and decreased disturbance by

recreationists and livestock in stream systems

should benefit all of the above avian species.

Increased connectivity between drainages will

facilitate population expansion of each

species as fragmented habitat is one of the

factors contributing to declines.

Saltmarsh common yellowthroat. The

saltmarsh common yellowthroat utilizes a

range of aquatic habitats in the San Francisco

Bay area. Because the ranges of the

yellowthroat and California red-legged frog

overlap in the periphery of San Pablo Bay and

its tributaries, in wetlands in Marin County

(e.g., Olema Marsh), in southern San

Francisco Bay streams (e.g., Coyote Creek),

and at Pescadero Marsh, protective measures

for the California red-legged frog that

enhance or protect riparian corridors and

marshes where they interface with salt

marshes, should also provide nesting,

foraging, and dispersal habitat for the

saltmarsh common yellowthroat. These areas

will particularly provide suitable habitat for

the yellowthroat during high tides when

refuge is required for survival.

Marsh sandwort and Gambel’s watercress.

Recovery efforts that protect habitat areas in

San Luis Obispo County will benefit these

plant species as well as the California redlegged frog. Further, mitigation of altered

hydrology and elimination of non-native

plant species (such as eucalyptus where it is

deemed a threat to water quality and riparian

habitat quality) will restore habitat for each

species.
60 Recovery Plan for the California Red-legged Frog
61

A. GUIDANCE FOR DEVELOPMENT OF WATERSHED MANAGEMENT PLANS

AND IMPLEMENTATION OF RECOVERY TASKS

The following guidelines should be used when implementing the recovery tasks as outlined in

Section B. They provide specific recommendations for minimizing the effects of various land

and water uses, predation, and air and water contamination and provide recommendations for

habitat preservation. These guidelines will be valuable when developing watershed

management and protection plans (see Task #1), developing mitigation measures for

development projects, during section 7 consultations under the Endangered Species Act, and

for regional conservation planning for the California red-legged frog.

1) Protect suitable habitats and buffers in perpetuity.

a. Encourage and assist counties and owners of large tracts of natural lands to

develop preserves, conservation banks, and/or mitigation banks.

Owners of large tracts of natural land (public and private) should be encouraged to

participate in conservation planning by establishing preserves or mitigation banks.

b. Purchase conservation easements or parcels from willing sellers where

acquisitions may protect existing populations, allow for expansion of

metapopulations, and increase the quantity of protected suitable habitat within

the range of the species.

Expanding the acreage of protected high quality habitat within core areas and high

priority watersheds will contribute to recovery of the California red-legged frog by

increasing opportunities for dispersal, population expansion, and recolonization. The

delineation of core areas (Figure 12, Table 4, and Appendix C) provides direction on

where habitat suitability and connectivity are considered important for long-term

recovery of the California red-legged frog and where land acquisition or protection is

necessary. In addition to expanding protection within designated core areas,

increasing the connectivity between core areas and occupied watersheds may also

increase recovery potential. Therefore, lands that are not designated as core areas

should also be evaluated using a landscape approach to determine their possible

importance to species recovery.

Several areas have been noted as being very important to the ecological function of

adjacent sites that currently support the California red-legged frog. For example,

protection of lands upstream from the Corral Hollow Ecological Reserve will increase

and maintain suitability of this Reserve for frogs. Protection of coastal areas owned

by the Hearst Corporation will allow for protection of frogs in the San Simeon

vicinity by maintaining contiguous habitat necessary for dispersal and population

expansion. Long-term protection of parcels in these, and other areas, should be

pursued via conservation easements or other means of permanent protection.

Isolated sites such as stock ponds, which currently support frogs in the Sierra Nevada

foothills, are also in need of protection. Protection of at least a 3-kilometer (2-mile)

radius from these isolated ponds may contribute to range expansion in the Sierras.

III. Outline of Recovery Actions
62 Recovery Plan for the California Red-legged Frog

Opportunities to acquire inholdings within National forests should be pursued and

vehicles for achieving this may include land swaps. Again, protection of the

watershed, including stream reaches up- and downstream of known populations and

adjacent uplands, will increase the potential for long term suitability of such sites for

the California red-legged frog.

c. Establish appropriate buffers within urban and agricultural areas on a site-bysite basis.

Buffers should be established and preserved through the same mechanisms used to

secure habitat. Incorporation of research on dispersal habits of the California redlegged frog, and influences of habitat type and gradient, should increase the

understanding of appropriate buffers by site. Dispersal habits and habitat needs of the

frog should be provided to planning agencies so that appropriately sized buffers,

habitat areas, and corridors (i.e., dependent on site-specific conditions, topography,

etc.) can be built into project plans.

2) Develop and implement guidelines for maintaining adequate water flow regimes,

particularly in California red-legged frog habitats downstream of impoundments,

water diversions, and residential or industrial developments.

Altered water regimes can result in a multitude of direct and indirect impacts to the

California red-legged frog and its habitat, ranging from unseasonable flows that disturb

egg masses to loss of aquatic habitat by excessive groundwater withdrawals or stream

diversions. Data should be collected to identify the in-stream flow needs necessary to

restore natural, seasonal flow cycles and thus maintain optimal habitat for protection and

recovery of the California red-legged frog and co-occurring species. Care must be taken to

consider the varying needs of co-occurring species and accommodate potential conflicts.

While water flows will vary with weather conditions and thus may not be consistently

maintained, particularly in drought conditions, measures should be proposed and

agreements implemented to secure the needed flows when diversions, impoundments, or

urban wastewater flows threaten the integrity of the hydrologic regime.

a. Provide water budgets to county planners and water districts that identify needs

for the California red-legged frog.

Work with authorities to secure appropriate flows, limit the amount of water pumped

from wells during late summer months and drought periods, and/or manage small

impoundments in a manner that increases suitability of habitat in reaches up- and

downstream of dams. Sites that are in need of water budgets include coastal streams,

particularly those in the Central Coast Recovery Unit (i.e., San Simeon Creek and

Santa Rosa Creek in San Luis Obispo County).

b. Manage dams and reservoirs that affect populations of the California red-legged

frog.

Water suppliers and reservoir operators should consider operational changes that

result in environmental enhancements while preserving water quality and quantity to

the extent consistent with environmental goals. Management actions may include

seasonally drawing down water levels to remove non-native aquatic predators or

release of flows to create and/or maintain breeding habitat for the California redlegged frog downstream of dams. Goals should include restoring natural hydrographs

and minimizing unseasonable flows.
Recovery Plan for the California Red-legged Frog 63

Diversions on the Los Padres National Forest and other public and private lands (i.e.,

other National Forests, Bureau of Land Management, State Parks) that have not

undergone environmental review should be analyzed for impacts to the California redlegged frog and associated species and managed for habitat suitability. Because small

impoundments can also create habitat for the California red-legged frog, site-specific

determinations of benefits and/or impacts are necessary.

c. Where feasible, remove dams that have eliminated or reduced populations of the

California red-legged frog on National Forest lands and other public lands.

Managers of public lands should consider removal of dams and diversions

(particularly those that divert springs) that are negatively affecting the extent and

suitability of California red-legged frog habitat. In particular, removal should be

considered when such facilities no longer serve their useful purpose and when they

could feasibly be replaced by other, less environmentally damaging facilities capable

of supplying water of equal or better quality compared to the facility proposed for

removal.

For example, the Matilija Dam on the Los Padres National Forest has been identified

as an obstacle to the flows necessary for suitable breeding habitat for the California

red-legged frog in Matilija Creek on the Los Padres National Forest land. Further,

careful review of the 190 spring diversions on the Los Padres National Forest, and

removal of these diversions where appropriate, is recommended. Where dam removal

is not feasible, modification of the structures and systems should be completed to

provide suitable habitat for the California red-legged frog.

Other locations where careful review and possible elimination of impoundments is

necessary include the tributaries to Año Nuevo State Park. Impoundments here are a

source of non-native predators (i.e., warm water fish and bullfrogs) (M. Westphal

pers. comm. 1998). Restoration via impoundment removal may be the best long-term

solution to the threat of non-native predation on the California red-legged frog at this

location.

In some cases, dams provide the requisite impoundment of water that is required for

California red-legged frog habitat where none existed before (e.g., stock ponds) so

surveys and suitability analyses must be carried out prior to removal.

3) Develop and implement best management practices to prevent or minimize adverse

impacts to the California red-legged frog from in-stream and stream bank activities

associated with mining operations.

Activities such as gravel mining and suction dredging can degrade California red-legged

frog habitat in streams and creeks by altering the morphology and hydrology of these

aquatic systems, facilitating the proliferation of non-native aquatic species and increasing

sedimentation. Identification of watersheds with this problem is needed for recovery with

subsequent development and implementation of measures that reduce effects.

a. Identify streams for which in-stream and stream bank activities associated with

mining threaten habitat suitability for the California red-legged frog.

A survey of streams which are subject to gravel mining operations is necessary. Placer

mining and gravel extraction impacts may be greatest in the Sierra Nevada foothills.
64 Recovery Plan for the California Red-legged Frog

b. Determine the effects of suction mine dredging, gravel extraction, and placer

mining on the California red-legged frog.

An analysis that evaluates the effects of suction mine dredging and placer mining on

the California red-legged frog and its aquatic habitat is necessary. While many water

quality impacts have been identified (e.g., increased sedimentation), determining the

relationship between degraded water quality and frog reproduction and survival will

aid development of management guidelines and minimization measures to protect the

subspecies.

c. Develop gravel mining guidelines for streams where gravel mining is identified

as a threat to the suitability of habitat for the California red-legged frog.

Upon identification of streams for which these activities are a threat to the suitability

of habitat for the frog, measures may be necessary to minimize the impacts to aquatic

habitat. Minimization measures or guidelines should be applied in suitable habitat for

the frog. Management guidelines may include such measures as: removal of artificial

pools that have been created by suction dredging and now harbor non-native aquatic

species (or may in the future), bank stabilization, reduction and containment of

sediments, reduction of highbanking, and removal of gravels and soils above the high

water mark and on adjacent terraces.

Appropriate sites for doing impact analyses and applying guidelines include portions

of the Los Padres National Forest (portions of the Santa Ynez, Ventura-Matijila, and

Piru watersheds), watersheds in the Sierran foothills, and other problem areas as they

are identified.

d. Eliminate mining activities in drainages with known California red-legged frog

populations.

In identified high use areas, elimination of mining activities within 1.5 kilometers (1

mile) up and downstream of known frog populations will contribute to recovery by

eliminating potential negative effects on frog reproduction and survival. Sediment

loads should be monitored for mining activities conducted greater than 1.5 kilometers

(1 mile) upstream to evaluate whether California red-legged frogs are negatively

impacted. If so, minimization measures should be enacted to reduce degradation of

water quality. Elimination of mining activities is recommended on all public lands

and in core watersheds where California red-legged frogs are threatened by such

activities. Where elimination is infeasible due to valid patented claims, and where

mining operations are already permitted under the state Surface Mining and

Reclamation Act, guidelines should be implemented to avoid impacts.

e. Identify areas where acid mine drainage may be affecting California red-legged

frog populations, and identify measures to reduce or eliminate the effects.

Acid mine drainage is associated with the extraction of many metals. High acidity can

have direct effects on the frog and their prey base, or indirect effects by interactions

with other actual and potential contaminants. Some elimination or reduction of

contaminant exposure might be accomplished through zoning regulations. This may

entail working with county planning departments and agricultural commission offices

to define areas where certain activities are not permitted or certain chemicals are

restricted.
Recovery Plan for the California Red-legged Frog 65

4) Control/eliminate non-native species/predators (plants, vertebrates, invertebrates)

using methods that are determined to be the most effective.

A large component of the threats to California red-legged frogs involves the presence of

non-native predators, particularly warm water fish, crayfish, and bullfrogs. In addition,

some regions in southern California may benefit from control of African clawed frogs.

Although introduced predators can be considered ubiquitous in many watersheds within

the current and historic range of the frog, areas of high concentrations should be identified

and the numbers of non-native predators reduced. As a short-term method, physical

removal of non-native predators may be most beneficial. However, pro-active means of

reducing the conditions in which non-native predators thrive is a long-term priority.

Sustainable land uses that maintain high suitability for the California red-legged frog

rather than degraded conditions where non-natives have a competitive advantage should

be encouraged.

a. Identify sites that require control or elimination of non-native predators.

Through implementation of this recovery plan, many sites needing non-native

predator control are expected to be identified. However, based on current information,

the following sites have been identified as areas which may benefit from non-native

predator removal: Garin Dry Creek and ponds/drainages in Pleasanton Ridge

Regional Park (Alameda County), Arroyo Del Valle (Alameda County), upper

Alameda Creek and other drainages in the Sunol Regional Wilderness (Alameda

County), Bollinger and Brushy drainages (Contra Costa County), Kellogg Creek,

Castro Creek and drainages in the Black Diamond Mines Regional Preserve (Contra

Costa County), Diablo Foothills Regional Park (Contra Costa County), portions of the

Golden Gate National Recreation Area including Tennessee Valley and bordering

drainages (Marin County), Mountain Lake in the Presidio, (San Francisco County),

Crystal Springs Reservoir and Pilarcitos Lake on San Francisco Water District lands

(San Mateo County), the Corral Hollow watershed (San Joaquin County), Oristemba

and Garzas Creeks (Stanislaus County), Año Nuevo State Park and Reserve (Santa

Cruz County), ponds and lakes in Henry W. Coe State Park (Santa Clara County),

ponds and lakes on Palassou Ridge ( Santa Clara County), Romero Creek and ponds

on Romero Ranch (Santa Clara and Merced Counties) Fort Hunter Ligget (San

Antonio and Nacimiento drainages, Monterey County), Little Oso Flaco Lake (San

Luis Obispo County), and areas within the Los Padres National Forest, Yosemite

National Park, Eldorado National Forest, and Plumas National Forest.

b. Eliminate predators utilizing various methods to determine the most effective

means.

Many methods for controlling/eliminating non-native predators exist and yield

differing results (i.e., pond drainage, physical removal, rotenone). Various methods

should be tested to determine which are the most successful and cost effective.

c. Eliminate breeding habitat of non-native predators.

In identified problem areas, potential and known breeding sites of non-native aquatic

predators (e.g., stock ponds, small reservoirs) should be eliminated near known or

potential California red-legged frog habitat. Physical removal (i.e., filling in a stock

pond known to be infested with non-native species) may be necessary; this may be

more cost effective and productive over the long-term than removing individuals.
66 Recovery Plan for the California Red-legged Frog

Surveys should be conducted prior to such actions to ensure that the California redlegged frog is not breeding in these areas.

d. Maintain watersheds that are free from non-native predators.

Some ponds (e.g., Mud Dam Pond on San Francisco Public Utility Commission

Lands and some ponds on East Bay Regional Park District lands) support the

California red-legged frog and are not infested with non-native predators. Careful

monitoring and preventative management should be carried out to avoid invasions.

e. Use appropriate animal control measures to reduce impacts of raccoons and

other predators associated with urbanization.

Preventative and reactive measures taken within urbanized areas may decrease the

proliferation of predators. Such measures may include waste management in public

parks and housing developments, control of feral pets, discouraging the public from

accidentally or intentionally feeding wild predators such as raccoons, and animal

removal if predator populations appear to be significantly detrimental to the

California red-legged frog breeding success and survival.

f. Remove arundo, tamarisk, cape ivy, and other non-native plant species if they

are threatening habitat suitability.

In addition to non-native animals, a number of non-native plants threaten the integrity

of the frog’s habitat in aquatic systems. These non-native plants can out-compete, and

ultimately replace, native plants resulting in the loss of plant species diversity and

wildlife habitat. The relationship between the presence of non-native plants and

habitat suitability for the frog should be investigated. If these plants threaten habitat

suitability, they should be removed. In the case of non-native plant removal, the

effectiveness of eradication should be verified and post-treatment revegetation efforts

should be conducted promptly to ensure adequate vegetative cover in treated areas.

Areas identified thus far as having an intense invasion of non-native plants include

the following aquatic systems: Santa Ynez, Ventura-Matilija, Santa Paula, Sespe, and

Piru watersheds on the Los Padres National Forest, San Simeon and Santa Rosa

Creeks in San Luis Obispo County, areas in the San Gabriel Mountains and most

southern California sites. More sites are expected to be identified in the future.

g. Decrease the extent of and/or cease artificial stocking of non-native fish.

Stocking of non-native fish should occur only in aquatic systems that have been

surveyed for sensitive native aquatic species and where these sensitive species are

deemed absent. Surveys should be conducted upstream and downstream from a

stocking site prior to stocking. Watersheds that support the California red-legged frog

should be allowed to revert to either a fishless system or a community of native

aquatic species, depending on the historic conditions. Stocking of non-native fish

should be discontinued in National Park waters, State and Regional Parks,

Vandenberg Air Force Base, and core watersheds.

h. Remove restrictions on the take of feral pigs and encourage their removal from

red-legged frog habitat including associated uplands.

i. Eliminate practice of releasing translocated urban predators such as raccoons,

skunks, and opossums into California red-legged frog habitat areas.
Recovery Plan for the California Red-legged Frog 67

5) Reduce the detrimental effects of livestock grazing and increase incidental benefits

associated with livestock grazing on public and private lands.

Although research is necessary to understand the interactions between livestock grazing

and the frog, and to determine the optimum grazing regimes for California red-legged frog

habitat suitability and survival (see task 10.12 below), opportunities currently exist to

manage grazed lands in a manner that reduces impacts to or enhances frog habitats.

a. Implement guidelines for construction, maintenance, and management of

artificial ponds.

Because of the variability of aquatic systems from either natural climatic changes or

anthropogenic effects, the survival of populations in all aquatic habitats may depend

on the continued presence of ponds, springs, or pools that are disjunct from streams.

In many California red-legged frog metapopulations, artificial ponds maintained for

watering livestock are the principal sources of the young frogs that annually

repopulate the watershed. Appendix D provides guidelines that may be used to create

and manage artificial ponds for the benefit of California red-legged frogs and/or

enhance existing ponds to increase suitability. Private landowners should be

encouraged to implement the recommended pond guidelines on a voluntary basis, and

public managers should implement these guidelines where California red-legged

productivity is low due to poor breeding habitat conditions in natural aquatic systems.

Areas where pond construction and maintenance are expected to benefit California

red-legged frogs include cattle ranches, dairy farms, and nurseries (particularly

nurseries along the central coast south of Half Moon Bay). At existing and future

nurseries, supplemental irrigation ponds can be constructed for use by frogs when

irrigation ponds are drawn down. Cost sharing incentives and safe harbor agreements

may be appropriate for landowners who choose to participate in habitat enhancements

such as pond creation (see Appendix E).

b. Increase the number of private landowners who develop and implement

California Rangeland Water Quality Management Plans.

Landowners should be encouraged to develop California Rangeland Water Quality

Management Plans. Because the primary goals of these plans are to maintain and

improve the quality of surface water, implementation of such self-initiated plans will

improve habitat conditions for the California red-legged frog.

c. Test grazing strategies to determine grazing regimes that are most compatible

with California red-legged frog breeding and survival and habitat suitability.

Several grazing strategies and guidelines may minimize impacts to the frog. Strategies

that should be analyzed include rest-rotation and deferred utilization, varied livestock

types (i.e., change from cow-calf operation to steers or breeds which utilize dry

habitats), and/or lowered stocking rates for lighter utilization levels to limit forage

removal.

d. Develop and implement grazing guidelines or enhance existing guidelines for

public lands which have been identified as having habitat quality concerns due to

livestock grazing.

Guidelines must be site-specific and could include actions such as: fencing, relocation

of water and salting sites away from wetlands, maintenance of stream bank stability
68 Recovery Plan for the California Red-legged Frog

(i.e., no more than 10 percent of natural stream bank stability altered by livestock

trampling, chiseling, and sloughing), management of upland herbaceous vegetation

such that utilization does not exceed 50 percent of annual growth (depending on the

site conditions), and monitoring of utilization and subsequent habitat suitability for

frogs.

Areas needing grazing guidelines to reduce impacts to frogs and increase suitability of

habitat include the following: portions of the East Bay Regional Park District (i.e.,

Garin Dry Creek Regional Park), areas of high levels of grazing on National forests

(i.e., portions of the Carmel, Cuyama, Sisquoc, and Piru watersheds on the Los Padres

National Forest), State parks, and publicly owned portions of core areas. Additional

areas should be included if overgrazing is negatively affecting the California redlegged frog.

e. Reduce water quality degradation associated with livestock grazing and horse

corrals.

Areas in which livestock and horses congregate typically experience high levels of

nutrients due to urination and defecation by these animals. This has been identified as

a problem on the Golden Gate National Recreation Area and Point Reyes National

Seashore, and it is likely that this problem exists in other areas throughout the range

of the frog. Measures should be implemented to alleviate water quality degradation.

Suggestions include limiting the extent of time that livestock/horses are allowed to

congregate in watersheds harboring the California red-legged frog. If a demonstrated

threat to California red-legged frogs exists, horse corrals should be moved to at least a

150-meter (500-foot) distance from known and potential breeding sites until

appropriate buffers are determined through experimental research.

6) Reduce the effects of timber harvest activities on the California red-legged frog and

its habitat.

Timber harvest activities are considered a threat to watershed integrity when guidelines

are not in place to reduce adverse impacts. This is a particularly important issue in the

North Coast foothills and the Sierra Nevada foothills.

a. Develop and implement timber harvest guidelines to reduce impacts to the

California red-legged frog and their habitat.

Guidelines for minimizing impacts associated with timber harvest activities should be

developed for each timber region within the current and historic range of the frog.

Implementation of guidelines should be refined for individual sites (i.e., based on

topography, watershed conditions).

b. Develop regional dichotomous keys for assessing potential effects of proposed

timber harvest plans.

As described in section I, part G of the Introduction (Regulatory Protection and

Conservation Measures), a dichotomous key exists to assist land managers and timber

harvesters in the analysis of potential project impacts. This key has been successfully

used by foresters, and is viewed as a means for harvesters to actively take part in the

analysis with a full understanding of the rationale for assessing impacts. This

dichotomous key should be refined for each recovery unit so that the key is more

specific to regional habitat conditions and harvest practices. Specifically, a refined
Recovery Plan for the California Red-legged Frog 69

key should be developed for the Sierra Nevada foothills, North Coast foothills, and

the Northern Transverse and Tehachapi ranges recovery units.

c. Design and maintain roads in a manner that reduces impacts.

Erosion control features should be established on skid trails and tractor roads

immediately upon completion of yarding on them in wet weather conditions. Road

surfaces should maintain a hard surface (e.g., rock hardness) during periods of road

use. Roads should be designed with the minimum width necessary to support the

proposed use, roads on steep slopes (greater than 50 percent) should be full-bench

design, and spoils should be disposed on grounds that are less than 30 percent slope

and remote from watercourses. New roads and those requiring reconstruction should

be out-sloped with rolling lips. The California Forest Practice Rules should be

consulted for additional measures to reduce impacts and sedimentation.

7) Develop site-specific guidelines for recreational activities to reduce or eliminate

impacts to the California red-legged frog where these activities pose an on-going

threat to habitat quality.

Hiking, fishing, horseback riding, and back country camping occur over large areas on

public lands such as National Forest, Bureau of Land Management, State, and regional

park lands. Habitat impacts associated with use of trails and roads, use of developed

recreation sites, and dispersed use include wetland vegetation trampling, soil compaction,

sedimentation, bank destruction, dammed pools, vegetation clearing, introduction of

contaminants, and introduction of non-native fish and wildlife species. Impacts to the

California red-legged frog may include direct loss of egg masses and tadpoles due to

trampling and decreased suitability of aquatic habitats due to the proliferation of nonnative predators, sedimentation of pools, vegetation clearing or trampling, and decreased

water quality.

a. Reduce the impacts of trail and road use on California red-legged frog habitat

within public lands.

Again, depending on the site-specific needs for California red-legged frogs, trails and

roads may need to be rerouted to avoid stream crossings and rerouted a distance of at

least 150 meters (500 feet) from wetlands (i.e., springs, wet meadows, ponds,

marshes). Where stream crossings are absolutely necessary, measures that ensure that

crossings do not degrade frog habitat should be implemented. Vehicular activities

should be excluded from riparian and other wetland areas unless adequate stream

crossings exist to prevent sedimentation. Roads near known source populations of the

California red-legged frog should be closed annually, if feasible, during the late

winter and spring to prevent the killing of subadult and adult frogs on roads. With

each of these actions, care must be taken to avoid impacting other species.

Management plans should include impact minimization actions such as: (1) closure or

reroutes of trails or trail segments that cause degradation of aquatic systems, (2)

development of trails and overlooks which provide the public opportunities to view

unique resources without impacting those resources, (3) closure and relocation of

campgrounds and other developments to areas that are within a 150-meter (500-foot)

distance from wetlands, (4) development of interpretive trails and signs to educate the

public about sensitive resources and habitats, (5) restoration of aquatic and upland

areas that have been heavily degraded by recreational activities, and (6) installation of

space barriers installed as appropriate to protect sensitive habitat areas. Existing
70 Recovery Plan for the California Red-legged Frog

guidelines for road development, maintenance, drainage, and surfacing should be

followed to decrease impacts to the California red-legged frog habitats.

b. Minimize off-highway vehicle impacts.

A high priority is to develop management guidelines for off-road vehicle uses where

recreation activities have resulted in sedimentation of streams and ponds and the

degradation of upland habitats. Off-road vehicle activities upstream of the Corral

Hollow Ecological Reserve are decreasing the suitability of the ecological reserve due

to high rates of sedimentation during peak stream flows. In addition, many areas in

National forests need management of off-road vehicle use in suitable and occupied

habitats to decrease impacts to the California red-legged frog and other sensitive

species. Sediment monitoring guidelines, permanent or seasonal closures, and

development and maintenance of siltation ponds are needed in these areas.

c. Reduce impacts on the California red-legged frog from developed recreation

sites and dispersed recreational use on public lands.

Developed sites, including day use areas and campgrounds, often attract

congregations of people around water. Management plans for developed recreational

sites on National Forest, State park, and Regional park lands are needed to minimize

impacts to the frog. Developed recreational sites in need of management include areas

along Arroyo Seco, Santa Ynez, Ventura-Matilija, Sespe, and Piru drainages on the

Los Padres National Forest. On the Los Padres National Forest, areas with greatest

concentrations of dispersed use include portions of the Carmel, Arroyo Seco, Big Sur,

Sisquoc, Santa Ynez, Ventura-Matilija, Santa Paula, Sespe, and Piru drainages. Other

areas of high priority that need management plans include State and Regional parks

that currently support populations of the California red-legged frog.

8) Decrease the exposure of the California red-legged frog and their habitat to

contaminants.

Currently, the sensitivity of the California red-legged frog to pesticides, herbicides, heavy

metals, air pollutants, and other contaminants is largely unknown. Research on the

relationship between the frog and pollutants is necessary and will contribute to the

knowledge base required for development of management guidelines with respect to

contaminants. Several contaminated areas have been identified (e.g., Vandenberg Air

Force Base) where the California red-legged frog may be exposed to toxins; at these sites,

contaminants should be removed and other measures that decrease exposure of the frog

should be undertaken.

a. Use habitat-based measures to prevent contamination of California red-legged

frog habitat.

Habitat-based recovery actions that prevent the movement of pesticides into the

aquatic environment should be used to reach this goal. For example, well-vegetated

riparian areas and/or vegetation buffers around natural and artificial ponds should be

protected and/or enhanced in agricultural, urban, and suburban areas to prevent aerial

drift and overland flow of chemicals into wetlands. Intensive farming should be

avoided within a 500-meter (1,500-foot) buffer from wetlands.
Recovery Plan for the California Red-legged Frog 71

b. Develop contingency guidelines for hazardous material spills.

Measures to avoid contact with hazardous material will preserve the integrity of

aquatic systems and habitats needed by the frog. Having contingency plans in place

will reduce the likelihood that unexpected spills will negatively affect the California

red-legged frog and associated species.

c. Identify point and non-point source pollution and develop guidelines to reduce

impacts.

Identification of pollution sources will provide the focus for implementation of

appropriate guidelines and impact minimization measures. Some point-sources have

been identified and include Las Tables Creek in the Lake Nacimiento drainage

(Monterey County) which receives acid mine drainage from the Buena Vista and Klau

Mercury mines, Chorro Creek (San Luis Obispo County) which received high levels

of chlorinated water (50 parts per million) in 1997, the Guadalupe Oil Field (San Luis

Obispo County), San Justo Reservoir (San Benito County) which has high selenium

levels, the Goleta vicinity (Santa Barbara County) where sediment and water samples

show high levels of benzene, arsenic, and selenium from past oil industry activities,

and ponds on Vandenberg Air Force Base (Santa Barbara County). Identification of

non-point sources should include waste water discharges and areas in which use of

agricultural chemicals is concentrated.

d. Clean aquatic habitats that support the California red-legged frog and are

known to be contaminated.

As noted above, several areas within the current range of the California red-legged

frog are known to support the subspecies despite high levels of contaminants. Clean

up and remediation are necessary at each site. For example, some ponds on the

Vandenberg Air Force Base are contaminated but support the frog. Researchers have

noted physical deformities and research is necessary to determine the causes.

California red-legged frogs should be removed from the site while clean up occurs

and either relocated or allowed to disperse back into ponds once water quality has

been improved.

e. Substitute strongly caustic fertilizers or their components with less dangerous

substances.

Amphibian mortality, skin lesions, and burns have been associated with the caustic

materials found in mineral fertilizers (Schneeweiss and Schneeweiss 1997). Less

dangerous substances should be used in place of these chemicals.

f. Stop contamination of riparian areas from the direct application of herbicides

and pesticides by road crews (e.g., county departments of transportation,

Caltrans)

The use of materials known to be toxic to aquatic and riparian species are routinely

applied for control of roadside weeds and other unwanted vegetation. This is

particularly important where ditches, riparian areas, and springs occur at roadsides.

9) Develop guidelines for fire management practices (i.e., prescribed burns, emergency

fire suppression, emergency water use) to decrease incidental impacts to the

California red-legged frog.
72 Recovery Plan for the California Red-legged Frog

Many public lands do not currently have specific guidelines for fire management

activities. Routine and emergency plans should be modified to include protective measures

for the frog while maintaining fire fighter safety and protecting life and property.

Prescribed burning should be used when doing so will enhance ecosystem health (e.g.,

reduce fuels, control non-native plants) and decrease chances of catastrophic fires.

However, prescribed burning should be carried out in upland habitats during seasons when

frogs are not likely to be dispersing or estivating in uplands, if ecologically appropriate.

Guidelines for emergency fire suppression could include such actions as: restricting the

use of fire retardant drops in wetland habitat areas; avoiding breeding pool habitat for

water supply sites; avoiding establishment of staging areas within a minimum of 150

meters (500 feet) from California red-legged frog habitat; prohibiting solid and sanitary

waste facilities in the vicinity of aquatic habitats; signing, fencing, or closing areas of

California red-legged frog breeding habitat; developing inspection and monitoring

requirements for operating plans; and briefing hand crews on locations and types of frog

habitats.

The current fire management guidelines used by State parks should be evaluated for

compatibility with the California red-legged frog and revised in a manner that enhances

the ecosystem and watersheds upon which the frog relies. This should also be done for

National forests and lands managed by the Bureau of Land Management where the

California red-legged frog is present. A priority is the implementation of best management

practices by California State Park staff in implementation of the State-wide burn program.

10) Develop and implement best management practices to prevent or minimize adverse

impacts to the California red-legged frog from in-stream and stream bank activities

associated with flood control actions.

Guidelines on flood control measures should be developed and implemented on public

lands. Guidelines could include actions such as: maintenance of appropriate levels of

down woody material in riparian zones and within a 150-meter (500-foot) distance from

ponds, marshes, and other aquatic habitats; avoidance of seeding/revegetating treated

areas with non-native species (including using mulch that may contain non-native seed

species); contour felling of trees within or just outside riparian zones to help reduce runoff

and sedimentation of streams; and monitoring to verify effectiveness of actions.

Guidelines should address impacts of flood control activities carried out upstream of

California red-legged frog habitat.

11) Implement watershed management and protection plans using cooperative

agreements and existing incentive programs.

Traditional fee title acquisition by government or private resource interests is an effective,

but expensive, way of protecting resources. Other mechanisms to protect habitat on

private lands include: 1) local zoning restrictions that prevent incompatible uses, 2)

transfer of development rights, 3) fee title donations, 4) sale or donation of conservation

easements, 5) land swaps, 6) sale and back lease or resale programs with restrictive

covenants, and 7) use of existing incentive programs (described in Appendix E). Support

and assistance of private landowners in conserving and recovering the frog may be gained

by developing economic and other incentive programs (relief from taxes, tax credits, tax

deductible habitat management expenses, safe harbor agreements).
Recovery Plan for the California Red-legged Frog 73

B. RECOVERY TASKS

1.0 Develop and implement watershed management and protection plans for core

areas.

While the California red-legged frog uses streams, ponds, and other wetlands to varying

degrees, an assumption of this recovery plan is that a varied landscape with multiple

opportunities for breeding within a watershed is optimum. For example, these frogs may

rely on artificial ponds for the majority of reproductive output but move into streams in

wet years or when suitability is increased via restoration. Thus, having both habitat

types in optimum condition within the landscape/watershed will provide the variety of

available habitats on which California red-legged frogs typically rely. Watershed

improvements are expected to increase habitat for the California red-legged frog by

providing suitable aquatic sites for breeding that are maintained by hydrological balance

and located within a matrix of adjacent uplands that are managed appropriately (i.e.,

have stabilized soils and are not fragmented).

Management and protection plans should be developed for each core area as listed in

Table 6. Watershed assessments will be necessary to determine restoration and land

management needs for each watershed. Methods to enhance habitat and minimize or

eliminate identified threats should be included in the management and protection plan.

Each plan should include proposals to incrementally protect, via conservation

easements, fee title, acquisitions, or other mechanisms, important breeding and dispersal

habitats. The Guidance for Development of Watershed Management Plans and

Implementation of Recovery Tasks (section III.A) should be used to assess the needs

within a particular drainage and to develop appropriate land use guidelines, threat

minimization measures, and/or land protection and restoration measures.

Because ownership within targeted watersheds is likely to encompass multiple land

owners, multi-entity cooperative watershed management plans will be necessary to

secure appropriate flows, control predators that may disperse into frog breeding habitats

from within or outside a watershed, combine restoration and enhancement efforts, and

manage use of uplands to allow for maintenance of suitable wetlands.

2.0. Develop and implement watershed management and protection plans for each

watershed that currently supports populations of the California red-legged frog

(priority 2 watersheds).

Within priority 2 watersheds, known or potential California red-legged frog habitat

should be managed in a manner which maintains or enhances the suitability for this

species. Land use guidelines should be implemented, as appropriate, to minimize

impacts to California red-legged frog populations (see Guidance for Development of

Watershed Management Plans and Implementation of Recovery Tasks). Preservation of

habitat, via acquisition or easements, may further protect the species in priority 2

watersheds.

3.0 Develop and implement watershed management and protection plans for each

watershed that was historically occupied by the California red-legged frog (priority

3 watersheds).

Priority 3 watersheds are areas that historically harbored California red-legged frogs. In

priority 3 watersheds, the likelihood of successful recovery is less than in core areas and

priority 2 watersheds. These areas will need (in most cases) extensive rehabilitation
74 Recovery Plan for the California Red-legged Frog

Table 6. Core areas targeted for development and implementation of management and protection plans for the

California red-legged frog.

Recovery Core Area Conservation Needs

Task #

1.1 Feather River Protect existing populations, remove non-native predators, protect and restore

wetlands within watershed, reestablish populations within this watershed and/

or augment existing populations with additional individuals.

1.2 Yuba River-South Fork Feather Protect existing populations, remove non-native predators, protect and restore

wetlands within watershed, reestablish populations within this watershed and/

or augment existing populations with additional individuals.

1.3 Middle Fork American River Control bullfrogs, reestablish populations within this watershed.

1.4 Cosumnes River-South Fork Protect existing populations, restore additional habitat, protect

American River connectivity, reestablish populations and/or augment existing population.

1.5 South Fork Calaveras Control bullfrogs, minimize effects of off-road vehicle use by eliminating

vehicle trails in California red-legged frog habitat, reestablish populations.

1.6 Tuolumne River Control non-native fish and amphibians, reestablish populations (e.g., at

Swamp Lake, Miguel Meadows).

1.7 Piney Creek Control bullfrogs, reestablish populations.

1.8 Cottonwood Creek Control bullfrogs.

1.9 Putah Creek-Cache Creek Reduce impacts of land uses, protect and restore wetland habitats, reestablish

populations.

1.10 Tributaries to Lake Berryessa Protect existing populations, reduce impacts of recreation, augment existing

populations.

1.11 Upper Sonoma Creek Protect existing populations, conduct subwatershed assessments and

management, control bullfrogs, maintain dams.

1.12 Petaluma Creek-Sonoma Creek Protect existing populations; reduce impacts of urban development; protect,

restore, and/or create breeding and dispersal habitat.

1.13 Point Reyes Peninsula Protect existing populations, control bullfrogs, continue genetics research on

R.a. aurora and R.a. draytonii, manage livestock and horse corrals to prevent

nutrient loading problems.

1.14 Belvedere Lagoon Encourage voluntary creation and/or management of habitat on private lands.

1.15 Fagan-Jameson Canyon- Protect existing populations from current and future urbanization, create and

Lower Napa River manage alternative breeding habitats, protect dispersal corridors.

1.16 East San Francisco Bay Protect existing populations; control non-native predators; study effects of

grazing in riparian corridors, ponds and uplands (e.g., on East Bay Regional

Park District lands); reduce impacts associated with livestock grazing; protect

habitat connectivity; minimize effects of recreation and off-road vehicle use

(e.g., Corral Hollow watershed); avoid and reduce impacts of urbanization;

protect habitat buffers from nearby urbanization.

1.17 Santa Clara Valley Protect existing populations, control non-native predators.
Recovery Plan for the California Red-legged Frog 75

1.18 South San Francisco Bay Protect existing populations, control non-native predators, increase

connectivity between populations, reduce erosion, implement guidelines for

recreation activities to reduce impacts, implement forest practice guidelines,

reduce impacts of urbanization.

1.19 Watsonville Slough-Elkhorn Protect existing populations, protect habitat connectivity, reduce impacts of

Slough agriculture, improve water quality, reduce impacts of urbanization .

1.20 Carmel River-Santa Lucia Protect existing populations, restore Carmel River watershed.

1.21 Gablan Range Protect existing populations, protect habitat connectivity, restore and create

habitat.

1.22 Estero Bay Protect existing populations, protect habitat connectivity, control non-native

predators, reduce water diversions to ensure adequate flows (e.g., Villa Creek,

Ellysly Creek).

1.23 Arroyo Grande Restore habitat, protect habitat connectivity.

1.24 Santa Maria-Santa Ynez River Protect existing populations; reduce contamination of habitat (e.g., clean

contaminated ponds on Vandenberg Air Force Base); control non-native

predators; implement management guidelines for recreation; cease stocking

dune ponds with non-native, warm water fish; manage flows to decrease

impacts of water diversions; implement guidelines for channel maintenance

activities; preserve buffers from agriculture (e.g., in lower reaches of Santa

Ynez River and San Antonio Creek).

1.25 Sisquoc River Restore habitat, control non-native predators, maintain Mono Debris Dam to

prevent the spread of bullfrogs, implement recreation guidelines, eliminate offroad vehicle use of habitat areas, implement guidelines for placer mining and

suction dredging.

1.26 Ventura River-Santa Clara River Restore habitat, control non-native predators and non-native plants, remove

Matilija Dam.

1.27 Santa Monica Bay- Protect existing populations (e.g. East Las Virgenes Creek), restore

Ventura Coastal Streams habitat, reestablish populations, augment existing population.

1.28 Estrella River Restore habitat.

1.29 San Gabriel Mountains Restore habitat, eliminate non-native predators, assess suitability for

reestablishment of populations, reestablish populations where appropriate.

1.30 Mojave River Restore habitat, assess suitability for reestablishment of populations,

reestablish populations where appropriate.

1.31 Santa Ana Mountain Restore habitat, assess suitability for reestablishment of populations,

reestablish populations where appropriate.

1.32 Santa Rosa Plateau Protect existing population, augment existing population with individuals,

remove non-native predators.

1.33 San Luis Rey Restore habitat, assess suitability for reestablishment of populations;

reestablish populations where appropriate

1.34 Sweetwater River Restore habitat, assess suitability for reestablishment of populations,

reestablish populations where appropriate.

1.35 Laguna Mountain Restore habitat, assess suitability for reestablishment of populations,

reestablish populations where appropriate.
76 Recovery Plan for the California Red-legged Frog

prior to recolonization or reestablishment. However, with intensive efforts and public

support, conservation of habitat in these watersheds is possible and may contribute to

the overall distribution and recovery of this species. Priority 3 watersheds include

unoccupied watersheds within the historic range including watersheds in the southern

Sierra Nevada and wetlands within the Central Valley (particularly wetlands that are on

U.S. National Wildlife Refuges).

4.0 Develop and implement conservation plans (e.g., Habitat Conservation Plans) for

the California red-legged frog on all State and regional parks and water/utility

district lands within the historic and current range.

Many State parks occur within the range of the frog and are key to providing habitat and

protective measures necessary for recovery of the frog. Parks that provide important

frog habitat include: Henry W. Coe State Park, Big Basin Redwoods State Park, Butano

State Park, Wilder Ranch State Park, and numerous others. Regional Park districts and

water and municipal utility districts that harbor frogs should also develop and

implement conservation plans, if existing land management plans are inadequately

protecting the California red-legged frog or have not yet been developed.

5.0 Work with county planners and local water districts to minimize the effects of

urban and suburban development and associated activities by developing regional

plans and/or habitat conservation plans.

City and county governments, as the primary agencies making land use decisions, need

to be involved in recovery planning. Cooperative programs and regional plans are

needed to coordinate local, public, and private land use planning with State and Federal

land use and recovery efforts for the California red-legged frog. Regional plans and/or

habitat conservation plans should incorporate recovery goals by including dispersal

opportunities between California red-legged frog populations, protecting large areas of

habitat (both breeding and dispersal) without fragmentation and edge effects, by

controlling exotic predators, and by implementing land use guidelines. Cooperative

programs should encourage and promote development of regional plans for cities and

counties in the area covered by this recovery plan. Development of cooperative

programs based on counties or at the watershed level may be most feasible.

6.0 Implement regional ecosystem strategies via existing regulatory processes to

minimize the effects of incidental take resulting from land uses and development

activities, and optimize benefits to the California red-legged frog derived from

mitigation and compensation actions.

Use of local, State, and Federal laws, regulations, and policies to protect the California

red-legged frog and its habitat provide existing, in-place conservation mechanisms. To

ensure that projects subject to these regulations do not preclude, but rather facilitate

recovery, project planning, and mitigation planning should utilize an ecosystem and/or

regional approach and include adaptive management.

6.1 Emphasize the connectivity of affected habitat areas or populations by

analyzing impacts and developing mitigation recommendations at the

regional level.

Numerous developments in a region are likely to result in intense cumulative

impacts such as large areas of habitat loss and fragmentation. Thus, a landscape

approach to impact analysis and mitigation planning is necessary. Conservation
Recovery Plan for the California Red-legged Frog 77

measures should enhance connectivity between habitat areas and should enhance

the effectiveness of mitigation sites or measures associated with adjacent

(perhaps already permitted) projects.

6.2 Design mitigation plans to enhance the viability of an entire known

metapopulation or group of populations.

Analysis of the status of California red-legged frog population distribution is

necessary to best manage populations and metapopulations while providing

flexibility in planning and mitigation development. Mitigation actions should

focus on protecting and enhancing source populations and maintaining

connectivity with other subpopulations or suitable habitat. If the impact analysis

indicates that a small portion of a known metapopulation (or group of populations

if the status of a metapopulation is undocumented or unknown) may be impacted

(approximately 10 percent or less of known subpopulations or breeding sites),

metapopulation viability may not be precluded with proper protection of the

source population(s). If a larger portion of the metapopulation (or group of

populations) will be negatively impacted, an emphasis on avoidance of impacts

will be necessary as well as appropriate habitat enhancement and preservation to

ensure long term viability of the metapopulation. Where dispersal between

populations is unclear, connectivity of habitats between known populations

should be maintained so that opportunities for interactions between populations

are not precluded.

6.3 Analyze project impacts by considering the variable breeding status of the

California red-legged frog in response to varying weather conditions.

Project and mitigation planning should include an analysis of the status of the

affected population(s) and/or metapopulation(s) to determine the importance of

the breeding habitat or subpopulations from one year to another. A historical

perspective on habitat use of the area is necessary when sufficient data are

available. If a project will negatively affect a number of breeding sites in an area

that includes all or part of a known population or group of populations, care

should be taken to ensure that despite varying current and future weather

conditions (i.e., extremely wet or dry years) there are sufficient breeding sites

available, over the long term, to allow for at least an average of 75 percent of

subpopulations to be reproductively successful in any given year.

6.4 Implement off-site mitigation when on-site conditions are not likely to be

beneficial for the frog.

Many proposed developments lead to unsuitable conditions for the California

red-legged frog. For example, housing developments typically result in increased

presence of non-native predators, altered flow regimes, and increased human use

of aquatic and upland habitats. In these cases, alternative sites for mitigation

should be considered to offset the effects of an action. Core areas as identified in

each recovery unit should be the focus of off-site mitigation or compensation.

Consolidation of mitigation actions may be achieved by development and

implementation of cooperative agreements with local and regional agencies.

Mitigation banks may be another appropriate vehicle for achieving this goal in

some areas.
78 Recovery Plan for the California Red-legged Frog

6.5 Include management and monitoring plans for mitigation measures that rely

on habitat construction, enhancement, or preservation.

Acreage that is set aside for frogs may not be adequate without proper

management. A management plan and an endowment or other funding

mechanism should be included with land preservation to maintain habitat

suitability in perpetuity. Management may include predator removal,

maintenance of created habitat, maintenance of adequate hydrology, and

monitoring.

6.6 Analyze past and future mitigation measures against clearly defined success

criteria to determine effectiveness.

While little is known about the optimum reproductive rates required for longterm population viability of the California red-legged frog, post-project surveys

should be conducted to document the reproductive status of the frog on

mitigation areas. Contingency measures should be implemented if/when it is

apparent that the California red-legged frog is not successfully reproducing.

6.7 Establish and maintain a database that tracks the amount of incidental take

authorized and the effectiveness of mitigation measures.

This database should be maintained by a central agency, updated and distributed

to project planners and reviewers on a regular basis (i.e., yearly), and referred to

by project planners and regulators during the project planning and review stage.

Incidental take and the effectiveness of mitigation measures should be quantified

by recovery unit and tracked for cumulative effects.

6.8 Summarize extent of incidental take previously authorized in biological

opinions pursuant to section 7(a)(2) of the Endangered Species Act and

describe the status of the species in relation to recovery goals per recovery

unit.

Each biological opinion that addresses take of the California red-legged frog and

its habitat should provide a summary of the extent of take previously authorized

per recovery unit.

6.9 Cease the use of frog barriers as a mitigation measure.

Mortality of the California red-legged frog due to frog barriers has been

documented at several locations (Rathbun et al. 1997, Rathbun and Scott, in litt.

1999). This measure should be discontinued until the design and installation of

frog barriers have been refined, tested, and proven safe.

7.0 Develop and implement guidelines for improving water quality within the range of

the California red-legged frog.

In the absence of data specific to the California red-legged frog, water quality standards

should be developed based on existing data from related species or from standard

toxicity tests. The standards can then be used to develop and implement appropriate

guidelines for use of chemicals and management of water quality.
Recovery Plan for the California Red-legged Frog 79

8.0 Implement air quality standards where poor quality is contributing to degraded

conditions for the California red-legged frog.

The Central Valley is the primary source of ozone and particulate air pollution in the

Sierra Nevada foothills (Cahill et al. 1996). Summer ozone is transported from the

Central Valley resulting in ozone levels in the Sierras that are as severe as those on the

valley floor. The proposed Federal standard of 8 parts per million should be met for the

Central Valley floor and Sierran foothills, particularly in the summer months when

transport is strongest.

9.0 Prevent the spread of disease and parasites in the California red-legged frog.

Observations of diseased and parasite-infected amphibians are now frequent. Amphibian

pathogens and parasites can be carried on the hands, footwear, or equipment of field

workers. These pathogens and parasites can spread to localities containing species with

little or no prior contact. Therefore, it is important for those involved in research in

wetland/pond habitats (including research on fish, invertebrates, and plants as well as

amphibians) to take steps to minimize the spread of disease agents and parasites.

9.1 Refine guidelines to minimize the spread of disease and parasites.

A Code of Practice, prepared by the Declining Amphibian Populations Task

Force of the International Union for the Conservation of Nature and Natural

Resources, provides guidelines for use by anyone conducting fieldwork at

amphibian breeding sites or other aquatic habitats. The Code is included as

Appendix F. Refinement of these guidelines may be necessary to ensure that the

most appropriate measures are implemented for research activities affecting the

California red-legged frog and its habitats.

9.2 Minimize chances of spreading disease and parasites when conducting field

surveys and research activities.

Upon development of disease and parasite minimization guidelines for the

California red-legged frog, the guidelines should be adhered to by all researchers

and surveyors. The guidelines should be listed as a term and condition for

scientific take permits.

10.0 Restore habitat conditions for the California red-legged frog at or near historical

localities, and where feasible, reestablish populations at extirpated localities (i.e.

unoccupied core areas).

The absence of the California red-legged frog in many areas within their historic range

indicates that habitat suitability must be enhanced. In many areas, however, even with

improved habitat conditions, natural recolonization is unlikely due to habitat

fragmentation and the large distances between known populations. Active augmentation

of populations and reestablishments following the guidelines in Appendix G, will be

necessary, upon completion of habitat restoration, to facilitate recovery.

Reestablishments are not necessary in each recovery unit but will be an important tool

to recovering the frog in recovery units 1, 2, and 8. The level of regulatory protection

for re-established populations is outlined in section 10(j) of the Endangered Species Act

(see Appendix G). Where mixed land ownership occurs, reestablishment efforts should

occur on public lands and only on private lands when landowners willingly volunteer

their lands for reestablishment efforts.
80 Recovery Plan for the California Red-legged Frog

10.1 Implement site assessments and restoration programs prior to

reestablishment of the California red-legged frog.

The following steps may be necessary prior to reestablishment of California redlegged frog populations:

■ Comprehensive watershed surveys in areas previously unsurveyed are

necessary to determine absence/presence and current habitat suitability.

■ Where the frog is absent, analyses of its habitat conditions are necessary to

determine reason for its absence.

■ Enhancement of habitat suitability, to the extent feasible, may be necessary in

areas where the frog is no longer present and habitat appears unsuitable.

Construction of breeding ponds and/or enhancement of existing breeding habitat

may also be necessary.

■ Analysis of the genetic differentiation of California red-legged frogs within

regions and between regions (particularly in the Sierra Nevada foothills and

southern California).

10.2 Conduct pilot captive rearing and reestablishment efforts to test the

effectiveness of methods, and modify protocol as necessary to improve the

effectiveness of reestablishments.

Appendix G provides initial guidelines for reestablishment efforts. These

guidelines will be refined as necessary. Reestablishment attempts should

continue using and testing various methods until at least one population in each

currently unoccupied core area is viable.

10.3 Reestablishment efforts should be carried out at each core area that does

not currently support the California red-legged frog.

10.3.1 Reestablish the frog in unoccupied core areas in Recovery Unit #1.

Unoccupied core areas in Recovery Unit #1 are: Yuba-South Fork

Feather River, South Fork Calaveras River, Tuolumne River, and Piney

Creek.

10.3.2 Reestablish the frog in unoccupied core areas in Recovery Unit #2.

The unoccupied core area in Recovery Unit # 2 is the Putah CreekCache Creek core area.

10.3.3 Reestablish the frog in unoccupied core areas in Recovery Unit # 8.

Unoccupied core areas in Recovery Unit #8 are: San Gabriel

Mountains, Mojave River, Santa Ana Mountain, San Luis Rey River,

Sweetwater River, and Laguna Mountain.
Recovery Plan for the California Red-legged Frog 81

11.0 Conduct research on the biology of the California red-legged frog and its habitat

requirements.

Much of the current status, general ecology, habitat requirements, and population trends

of this subspecies is unknown. Research is necessary in many areas to fully understand

the California red-legged frog, its relationship to its environment and its response to

various threats. Completion of recommended research projects will provide additional

information needed to refine recovery criteria and actions, and assist in determining if

and when delisting is appropriate. Data will also provide important guidance for

adaptive management.

11.1 Develop a California red-legged frog survey protocol.

A standardized protocol approved by us is necessary for this subspecies.

11.2 Identify areas for which no surveys of the California red-legged frog have

been carried out or where data are out-dated; conduct surveys in these

areas, obtaining private landowner permission to survey where necessary.

A better understanding of the distribution of the California red-legged frog is

needed. Many areas throughout the historic and current range of the frog have not

recently been surveyed and in some cases, never been surveyed. Most private

lands throughout the range of the California red-legged frog have not been

currently surveyed and represent a large gap in the understanding of this

subspecies. When potential California red-legged frog habitats are identified and

appropriate permissions have been obtained from private landowners, permitted

researchers should survey for the frog using the approved survey protocol.

Participation with willing landowners is essential to expand the scope of surveys

to private lands. One means may be to develop cooperative arrangements with

private landowners and managers of municipal lands. In addition, a joint United

States and Mexico effort to survey and protect California red-legged frog

populations and their habitat in Mexico is needed.

The following regions have been identified as areas which need current surveys.

Additional areas will inevitably be identified throughout implementation of the

recovery plan.

11.2.1 Conduct surveys in the Tehachapi Mountains.

11.2.2 Conduct surveys in the Santa Monica Mountains.

11.2.3 Conduct surveys in the Sisquoc River.

11.2.4 Conduct surveys in the upper Salinas River drainage including the

Estrella-San Jose system in San Luis Obispo County.

11.2.5 Conduct surveys in the Carrizo Plain and San Juan Creek.

11.2.6 Conduct surveys on Bureau of Land Management lands

(particularly in Recovery Unit # 6).

11.2.7 Conduct surveys within the historic and current range in the Sierra

Nevada.
82 Recovery Plan for the California Red-legged Frog

11.2.8 Conduct surveys on all other lands identified as unsurveyed or

where survey data is not recent (within the last 5 years).

11.3 Monitor known California red-legged frog populations.

A better understanding of the demographics and distribution will give a fuller

picture of population viability and threats to California red-legged frog

populations. These data are necessary to assess the species’ status over time.

Identification of source and sink populations should be included under this

recovery action.

11.3.1 Develop a population monitoring program.

Protocols for the collection and analysis of qualitative and quantitative

monitoring data should be developed. One approach may be to monitor

representative populations such that the viability of a group of

populations or a known metapopulation can be estimated.

11.3.2 Conduct qualitative assessments of all known populations.

Each population should be monitored to determine its status. Parameters

to be noted include presence/absence of suitable habitat, habitat

modification, disturbance, threats, and other factors.

11.3.3 Conduct quantitative assessments of representative populations.

Representative populations, in each recovery unit, will be chosen to be

monitored in greater detail using a protocol as defined under Task

11.3.1. Quantitative data needs include, but are not limited to, numbers

of individuals per age class, reproductive rates, survival, recruitment

rates, immigration and emigration rates. This information should allow

for the identification of source and sink populations.

11.3.4 Researchers and surveyors should, as a term and condition for

holding a section 10(a)(1)(A) scientific take permit, provide survey

and monitoring information to us and the California Department of

Fish and Game for input into appropriate databases.

Survey data should be provided to the California Department of Fish and

Game’s Natural Heritage Program for input into their Natural Diversity

Database on a yearly basis. In addition, population monitoring data and

habitat condition information should be consolidated into a database,

and maintained by our Sacramento, Ventura, and Carlsbad Fish and

Wildlife offices. This database should be accessible to all interested

parties including planning agencies, researchers, and the general public.

11.3.5 Use the results obtained from the monitoring of the California redlegged frog populations to determine where recovery efforts need to

be focused and to change prioritization of actions and locations if

necessary.

A contingency plan should be developed and implemented to best

respond to success and/or failure of previously implemented recovery
Recovery Plan for the California Red-legged Frog 83

methods. For example, if bullfrog eradication programs have resulted in

expenditure of funds with little success, alternatives should be

investigated and implemented. Further, if surveys reveal areas of source

populations that are not identified as core areas, the delineations of core

areas should be re-defined or expanded as appropriate.

11.3.6 Track status and recovery of California red-legged frog populations

per recovery unit and propose delisting where appropriate.

Monitoring of frog population trends, habitat conditions, and status of

threats may indicate that delisting is appropriate. It is likely, however,

that recovery will occur at different rates per region; recovery units with

lower recovery potential will require extensive management and

monitoring. If distinct vertebrate population segments are identified,

these may be delisted independently when appropriate.

11.3.6.1 Track status and recovery in Recovery Unit # 1.

11.3.6.2 Track status and recovery in Recovery Unit # 2.

11.3.6.3 Track status and recovery in Recovery Unit # 3.

11.3.6.4 Track status and recovery in Recovery Unit # 4.

11.3.6.5 Track status and recovery in Recovery Unit # 5.

11.3.6.6 Track status and recovery in Recovery Unit # 6.

11.3.6.7 Track status and recovery in Recovery Unit # 7.

11.3.6.8 Track status and recovery in Recovery Unit # 8.

11.4 Conduct population viability analyses for California red-legged frog

metapopulations throughout the range as appropriate.

Population viability analyses are tools that can identify populations in need of

recovery actions, as opposed to those that may be viable over the long-term

without intervention. Population viability analyses also may help identify the best

sites for reestablishment (i.e., identify metapopulations that may require

additional subpopulations for long-term viability), determine the effectiveness of

recovery actions (i.e., determine whether population growth rates are sufficient to

ensure long term viability), determine whether recovery criteria are appropriate or

need revision (i.e., whether the recovery goals are adequate to ensure long-term

viability of the subspecies), determine minimum population sizes required for

long-term viability, determine the anticipated time when recovery goals can be

reached, and provide many other answers related to population trends.

11.5 Study metapopulation dynamics, particularly the California red-legged frog

movements, among subpopulations.

This information will be used to determine whether active reestablishment efforts

are necessary following habitat restoration. Information on metapopulation

dynamics, in conjunction with frog monitoring data, will also help define isolated
84 Recovery Plan for the California Red-legged Frog

populations that are at risk of local extirpation, and identify source and sink

subpopulations.

11.6 Conduct research to better understand the ecology of the California redlegged frog including the use of uplands, dispersal habits, and overland

movements.

Environmental factors and habitat characteristics that hinder or facilitate

movement of various life stages should be determined. This will assist in the

development of best management practices, appropriate buffers from

disturbances, and optimum preserve design and size.

11.7 Investigate the effects of contaminants issues including ozone, pesticides,

herbicides, heavy metals, salinity, selenium, agricultural chemicals,

hydrocarbons, chlorine, ultraviolet radiation, estrogen mimics, airborne

contaminants, methoprene and other chemicals used to control mosquitoes,

and others as appropriate (e.g., detergents).

The effects of contaminants on the California red-legged frog have not been

widely studied and this is an area where research is needed. As noted above,

toxicity tests are needed to determine the effects of contaminants, the levels at

which detrimental effects occur, and measures required to minimize the effects

of chemicals. Further, the transport of contaminants from primary sources (e.g.,

Central Valley) to distant areas (e.g., the Sierran foothills) should be investigated.

Research on the effects and transport of contaminants will provide information

necessary for establishing sound air and water quality standards. In addition, risk

assessments of pesticides typically fail to evaluate the breakdown by-products.

Recent research suggests these by-products may pose a threat to amphibians (La

Clair 1998) although these experiments used 15,000 times the label rate and still

found low levels of deformity or mortality (P. Bindings in litt. 2000). Therefore,

the effects of breakdown by-products of pesticidal chemicals should also be

evaluated

11.8 Conduct research on the effects of mosquitofish including the development

of alternatives to mosquitofish use.

Mosquitofish are considered to be a predator of the California red-legged frog

although there are some sites where the species coexist. Additional research is

needed to better understand how these two species interact. Alternatives to the

use of mosquitofish as a means of mosquito abatement should be investigated to

decrease this practice if it does indeed pose a threat to the frog. Alternatives

include other biological control methods such as the application of several

species of bacteria (Bacillus sp.) and a fungus (Lagenidium giganteum) which

attacks and kills only mosquitoes. The implications of introductions of these

other control agents, however, may require extensive research. To implement this

task, we should work with mosquito and vector control districts to minimize

conflicts between public health and the California red-legged frog, and look for

sources of funding for necessary research.

11.9 Conduct research on the ecology of non-native species.

To better understand the interactions with and effects on the California redlegged frog and gain an understanding on the best management of habitats (i.e,
Recovery Plan for the California Red-legged Frog 85

management that favors red-legged frogs over non-native predators), more

information on the distribution, life histories, and habitat needs of non-native

predators is needed. An important component of this task is to gather such

information on bullfrogs. Bullfrogs should be studied at a minimum of three

northern coastal sites, three northern non-coastal sites, three southern coastal

sites, and three southern non-coastal sites, to consider variations in the bullfrog’s

life history within the range of the California red-legged frog. Another research

need is to determine effects of non-native species including crayfish, non-native

fish, and African clawed frogs.

11.10 Determine the genetic and ecological relationships between Rana aurora

draytonii and R. a. aurora.

Red-legged frogs in the intergrade zone from northern Marin County to southern

Del Norte County have not been assigned to either subspecies (northern redlegged frog or California red-legged frog). Based on morphological and

behavioral differences, researchers have suggested that the two subspecies may

actually be distinct species and that the frogs in the intergrade zone may represent

a zone of hybridization between the two species (G. Fellers pers. comm. 1999).

Genetic research is needed to clarify systematic relationships and allow a more

precise identification of the northern limits of the geographic distribution of the

California red-legged frog.

11.11 Determine whether distinct vertebrate population segments are identifiable

for the California red-legged frog.

Portions of the range of the California red-legged frog may be delisted

incrementally, provided the delisted portions qualify as distinct population

segments (defined in U.S. Fish and Wildlife Service 1996e). Research is needed

to determine whether particular recovery units, combinations of recovery units, or

other portions of the range of the frog meet the definition of distinct population

segments. Such research would address whether portions of the range are

‘discrete’ and ‘significant’ in relation to the remainder of the species (as described

in Section II-c and in U.S. Fish and Wildlife Service 1996e).

11.12 Conduct experimental manipulations of habitat to determine habitat

requirements of the frog, and subsequently, develop habitat creation and

restoration.

One of the most fruitful ways to investigate the habitat requirements of California

red-legged frogs is through creation and manipulation of habitats. These

investigations will serve two needs: to better understand habitat requirements of

the frog, and refine the methods for creation, improvement, and management of

habitat (natural and artificial). Experiments could include examination of the

optimum structure (i.e., depth, size) of artificial ponds and the optimum

hydroperiod for maintaining suitability for the California red-legged frog, while

decreasing the chances of non-native predator proliferation. Responses of the redlegged frog to habitat experiments need to be carefully monitored over a period

of 5 years minimum.

11.13 Conduct studies on the interactions of cattle grazing and California redlegged frogs.

Experimental manipulations with habitat controls will best assist land managers
86 Recovery Plan for the California Red-legged Frog

in the development of appropriate grazing regimes. In particular, to determine

the effects of various grazing regimes, it will be extremely beneficial to

experimentally fence portions of riparian zones, ponds, springs, and other

aquatic bodies to exclude livestock to varying degrees and over differing time

periods.

11.13.1 Determine the effects of livestock waste on frogs, particularly larval

development.

Congregation of livestock and horses (i.e., watering troughs, corrals)

may be a source of concentrated waste. Research is necessary to fully

understand the effects on all life stages of the California red-legged frog

and to determine the appropriate avoidance buffer needed to minimize

impacts to the frog.

11.13.2 Determine grazing thresholds, on a site by site basis, that ensure

optimum habitat suitability for the California red-legged frog.

Areas that need further research include determination of appropriate

stocking densities, seasonality of grazing, and residual dry matter levels

for California red-legged frog habitat suitability.

11.14 Develop and/or refine a protocol for a captive rearing and propagation

program.

California red-legged frogs from captive rearing and propagation efforts may be

required for reestablishment efforts or as an insurance measure to forestall

extinction of wild populations in the event of catastrophic population declines.

Propagation techniques should be designed to minimize both the loss of genetic

diversity and the introduction and spread of non-native diseases. Laboratory

experiments should only use frogs from captive propagation efforts.

11.15 Investigate the effects of eucalyptus on water quality and habitat suitability

for California red-legged frogs.

Stream reaches which are dominated by eucalyptus may not be suitable for the

California red-legged frog. The relationship of eucalyptus and habitat suitability

for the frog should be examined.

12.0 Increase public awareness and involvement in the protection of the California redlegged frog and native, co-occurring species.

Implementation of recovery actions may depend on the level of awareness of public

landowners, private landowners, conservation groups, planning interests, and

stakeholders. Outreach plans and educational programs explaining the life history and

habitat needs of the species and the goals of recovery will be an important part of

implementation.

12.1 Develop and implement outreach plans.

Plans should focus on providing information to interested and affected

landowners about: (1) the California red-legged frog, (2) what is meant by

recovery, and (3) how recovery can be achieved. Private landowners should
Recovery Plan for the California Red-legged Frog 87

become familiar with the frog and/or frog habitat that occur on their land, with

the significance of the populations, and with available conservation measures,

including incentive programs. For private lands with potential occurrences of the

California red-legged frog (i.e., lands with historic occurrences or otherwise

within the range of the subspecies), permission should be sought from

landowners to conduct surveys (task 11.2). If populations of the California redlegged frog are identified, landowners should be informed of their significance

and should be encouraged to follow land uses guidelines that protect the species

and its habitat.

We should offer periodic updates to the press and general public regarding the

status of the California red-legged frog and recovery efforts. Creation of exhibits

containing live frogs in natural frog habitat should be encouraged if exhibits are

also used to gather pertinent research information such as captive propagation

techniques. The National Wildlife refuges, Point Reyes National Seashore,

Golden Gate National Recreation Area, Año Nuevo and/or other State parks,

National Forests, and regional park districts should be excellent locations for

providing such educational opportunities to the public.

12.2 Develop and implement participation plans.

Participation plans will assist in the realization of recovery goals by getting

commitments from participating agencies and stakeholders to implement

recovery actions where feasible. Implementation of recovery tasks will require

cooperative efforts on the part of resource and regulatory agencies, regional,

county, and city park districts, local landowners, conservation groups, and

planning interests. Development and implementation of separate participation

plans in each recovery unit is necessary.

12.2.1 Develop a participation plan for Recovery Unit # 1.

12.2.2 Develop a participation plan for Recovery Unit # 2.

12.2.3 Develop a participation plan for Recovery Unit # 3.

12.2.4 Develop a participation plan for Recovery Unit # 4.

12.2.5 Develop a participation plan for Recovery Unit # 5.

12.2.6 Develop a participation plan for Recovery Unit # 6.

12.2.7 Develop a participation plan for Recovery Unit # 7.

12.2.8 Develop a participation plan for Recovery Unit # 8.

12.3. Provide technical assistance to private landowners who wish to voluntarily

improve conditions for the California red-legged frog.

A significant portion of recovery can be achieved through landowners who may

voluntarily improve habitat conditions for the California red-legged frog.

Landowners should be provided technical guidance such as guidelines for

wetland/pond management when requested (see Appendix D).
88 Recovery Plan for the California Red-legged Frog

13.0 Assess effects of various conservation efforts on co-occurring, native species.

Population data on listed and non-listed sensitive, co-occurring native species (Table 2)

will aid in their preservation. Improved habitat conditions may lead to increased

populations of species of concern and thus may forestall the need to list these species in

the future. Although it is assumed that enhancement of habitat conditions for the

California red-legged frog will benefit other native species, the impacts of enhancement

efforts on co-occurring, native species should be assessed.

13.1 Monitor co-occurring, native species.

There must be sufficient monitoring of populations and reproduction to detect

any detrimental effects that may arise from habitat improvements directed at

improving conditions for the California red-legged frog. Species-specific habitat

information should be collected on an as needed basis. This task can be achieved

through coordination with ongoing recovery efforts for associated listed species.

13.2 Implement remediation, where appropriate.

If conservation efforts cause declines in populations of listed or non-listed cooccurring species, remediation efforts should be developed and implemented.
89

This implementation schedule outlines actions and estimated costs for this recovery plan. It is a

guide for meeting the objectives discussed in this recovery plan. This schedule describes and

prioritizes tasks, provides an estimated time table for performance of tasks, indicates

responsible agencies, and estimates costs of performing tasks. These actions, when

accomplished, should recover the California red-legged frog and co-occurring species.

KEY TO ACRONYMS USED IN THE IMPLEMENTATION SCHEDULE

Definition of task priorities:

Priority 1 An action that must be taken to prevent extinction or prevent the species from

declining irreversibly in the foreseeable future.

Priority 2 An action that must be taken to prevent a significant decline in the species’

population or habitat quality, or some other significant negative impact short of

extinction.

Priority 3 All other actions necessary to meet recovery or conservation objectives.

Definition of task durations and costs:

Continual A task that will be implemented on a routine basis once begun.

Ongoing A task that is currently being implemented and will continue until action is no

longer necessary.

TBD To be determined.

* Continued implementation of task expected to be necessary after delisting.

† Task expected to be necessary until delisting of species (possible by 2025).

Responsible parties are those agencies who may voluntarily participate in any aspect of

implementation of particular tasks listed within this recovery plan. Responsible parties may

willingly participate in project planning, funding, provide technical assistance, staff time, or

any other means of implementation.

Costs of some recovery tasks cannot be estimated at this time. Costs of developing and

implementing watershed management and protection plans will vary with local circumstances

and details of individual plans. Sites for reestablishment of California red-legged frogs have

not yet been determined, so costs of assessment and restoration cannot be estimated. The

scope of necessary contaminants studies depends on results of ongoing research.

IV. Implementation Schedule
90 Recovery Plan for the California Red-legged Frog

Responsible parties:

ACE Army Corps of Engineers

ADC Animal Damage Control

BLM Bureau of Land Management

BOR Bureau of Reclamation

BRD Biological Resources Division, U.S. Geological Survey

CDFG California Department of Fish and Game

CDPR California Department of Parks and Recreation

CDF California Department of Forestry and Fire Protection

COUN County

DOD Department of Defense

DWR California Department of Water Resources

EBRPD East Bay Regional Park District

EPA Environmental Protection Agency

FWS U.S. Fish and Wildlife Service

FS U.S. Forest Service

MUD Municipal Utility District

MULTI Multiple public land agencies

MVCD Mosquito Vector Control District

NPS National Park Service

TNC The Nature Conservancy

Tribe Local Native American tribe(s)

UCNRS University of California Natural Reserve System

UNIV University or academic researchers

WMD Local Water Management Districts

Potential lead responsible parties are designatd in bold.
Recovery Plan for the California Red-legged Frog 91 Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 1 1.1 Develop and implement a management and protection plan for Core Area #1 (Feather River). continual* Plumas National Forest, Lassen National Forest, FWS TBD 1 1.2 Develop and implement a watershed management and protection plan for Core Area #2 (Yuba River-South Fork Feather) continual* Plumas National Forest, FWS, private TBD 1 1.3 Develop and implement a management and protection plan for Core Area #3 (Middle Fork American River) continual* Eldorado National Forest, FWS, private TBD 1 1.4 Develop and implement a management and protection plan for Core Area #4 (Cosumnes River-South Fork American River) continual* Plumas National Forest, FWS, BLM, DWR, USFS, FWS, El Dorado County, El Dorado Irrigation District, American River Conservancy private TBD 1 1.5 Develop and implement a management and protection plan for Core Area #5 (South Fork Calaveras River) continual* FWS, USFS–Calaveras Ranger District, private TBD 1 1.6 Develop and implement a watershed management and protection plan for Core Area #6 (Tuolumne River) continual* Yosemite National Park, FWS TBD 1 1.7 Develop and implement a watershed management and protection plan for Core Area #7 (Piney Creek) continual* Stanislaus National Forest, FWS TBD
92 Recovery Plan for the California Red-legged Frog Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 1 1.8 Develop and implement a watershed management and protection plan for Core Area #8 (Cottonwood Creek) continual* MULTI TBD 1 1.9 Develop and implement a management and protection plan for Core Area #9 (Putah Creek-Cache Creek) continual* BLM, FWS, private TBD 1 1.10 Develop and implement a management plan for Core Area #10 (Tributaries to Lake Berryessa) continual* FWS, BLM, USBR, CDFG, UCNRS, Quail Ridge Wilderness Conservancy TBD 1 1.11 Develop and implement a watershed management and protection plan for Core Area #11 (Upper Sonoma Creek) continual* CDPR, FWS TBD 1 1.12 Develop and implement a watershed management and protection plan for Core Area #12 (Petaluma Creek- Sonoma Creek) continual* FWS, Sonoma Land Trust, private TBD 1 1.13 Develop and implement a watershed management and protection plan for Core Area #13 (Point Reyes Peninsula) continual* NPS, CDPR, Marin Municipal Water District, FWS TBD 1 1.14 Develop and implement a watershed management and protection plan for Core Area #14 (Belvedere Lagoon) continual* FWS, private TBD 1 1.15 Develop and implement a management and protection plan for Core Area #15 (Fagan-Jameson Canyon-Lower Napa River) continual* FWS, Land Trust of Napa County, City of American Canyon TBD
Recovery Plan for the California Red-legged Frog 93 Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 1 1.16 Develop and implement a management and protection plan for Core Area #16 (East San Francisco Bay) continual* EBRPD, FWS, CDFG, CDPR, EBMUD, Lawrence Livermore Laboratory, DWR, USBR, TNC, private TBD 1 1.17 Develop and implement a watershed management and protection plan for Core Area #17 (Santa Clara Valley) continual* MULTI TBD 1 1.18 Develop and implement a management and protection plan for Core Area #18 (South San Francisco Bay) continual* CDPR, CDFG, FWS. private TBD 1 1.19 Develop and implement a management and protection plan for Core Area #19 (Watsonville Slough–Elkhorn Slough) continual* Elkhorn Slough National Estuarine Research Institute, CDPR, FWS, private TBD 1 1.20 Develop and implement a management and protection plan for Core Area #20 (Carmel River-Santa Lucia) continual* CDPR, Los Padres National Forest, FWS, private TBD 1 1.21 Develop and implement a management and protection plan for the Core Area #21 (Gablan Range) continual* FWS, Pinnacles National Monument, private TBD 1 1.22 Develop and implement a management and protection plan for the Core Area #22 (Estero Bay) continual* CDPR, FWS, private TBD
94 Recovery Plan for the California Red-legged Frog Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 1 1.23 Develop and implement a management and protection plan for Core Area #23 (Arroyo Grande) continual* CDPR, FWS, private TBD 1 1.24 Develop and implement a management and protection plan for Core Area #24 (Santa Maria-Santa Ynez River) continual* Los Padres National Forest, Vandenberg Air Force Base (DOD), CDPR, FWS, private TBD 1 1.25 Develop a management and protection plan for Core Area #25 (Sisquoc River) continual* FWS, Los Padres National Forest TBD 1 1.26 Develop a watershed management and protection plan for Core Area #26 (Ventura River-Santa Clara River) continual* Los Padres National Forest, FWS, private TBD 1 1.27 Develop and implement a watershed management and protection plan for Core Area #27 (Santa Monica Bay- Ventura Coastal Streams) continual* CDPR, Santa Monica National Recreation Area, Las Virgenes Institute, FWS, private TBD 1 1.28 Develop a watershed management and protection plan for Core Area #28 (Estrella River) continual* FWS, private TBD 1 1.29 Develop a watershed management and protection plan for Core Area #29 (San Gabriel Mountains) continual* Angeles National Forest, FWS TBD 1 1.30 Develop and implement a management and plan for Core Area #30 (Mojave River) continual* San Bernadino National Forest, FWS TBD
Recovery Plan for the California Red-legged Frog 95

Task

Priority

Implementation Schedule for the California Red-legged Frog Recovery Plan

Task

Number

Task Description Task Duration Responsible Parties Total

Costs

FY1 FY2 FY3 FY4 FY5

Cost Estimate (in $1,000 units)

Potential lead agencies are designated in bold.

1 1.31 Develop and implement a watershed 

management and protection plan for 

Core Area #31 (Santa Ana Mountain)

continual* Cleveland 

National Forest, 

FWS

TBD

1 1.32 Develop and implement a watershed 

management and protection plan for 

Core Area #32 (Santa Rosa Plateau)

continual* TNC, CDFG, FWS, 

Cleveland National 

Forest, private

TBD

1 1.33 Develop and implement a watershed 

management plan for Core Area #33 

(San Luis Rey) 

continual* Tribe, FWS, WMD, 

private,

TBD

1 1.34 Develop and implement a watershed 

management plan for Core Area #34 

(Sweetwater River)

continual* FWS, CDFG, 

Sweetwater Authority 

(WMD)

TBD

1 1.35 Develop and implement a watershed 

management and protection plan for 

Core Area #35 (Laguna Mountain)

continual* Cleveland 

National Forest, 

FWS, private

TBD

1 4 Develop and implement conservation 

plans for the California red-legged frog 

for all State and regional parks and 

water/utility districts within the 

historic and current range

continual* CDPR, Regional 

Parks, MUDs, FWS

TBD

1 5 Work with county planners and local 

water districts to minimize effects of 

urban and suburban development by 

creating regional plans or habitat 

conservation plans

ongoing* FWS, local 

governments and 

water districts

12 0.5 0.5 0.5 0.5 0.5

1 6.1 Emphasize connectivity of affected 

habitat areas or populations by 

analyzing impacts and developing 

mitigation recommendations at the 

metapopulation and regional level

ongoing* FWS 18 0.75 0.75 0.75 0.75 0.75
96 Recovery Plan for the California Red-legged Frog Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 1 6.2 Design mitigation plans to enhance the viability of an entire metapopulation ongoing† FWS 12 0.5 0.5 0.5 0.5 0.5 1 6.3 Analyze project impacts by considering the variable breeding status of frogs in response to varying weather conditions ongoing† FWS 12 0.5 0.5 0.5 0.5 0.5 1 6.4 Implement off-site mitigation when on- site conditions are not likely to be beneficial for the frog ongoing† FWS 18 0.75 0.75 0.75 0.75 0.75 1 6.5 Include management and monitoring plans for mitigation measures that rely on habitat construction, enhancement or preservation ongoing† FWS 18 0.75 0.75 0.75 0.75 0.75 1 7 Develop and implement guidelines for improving water quality within the range of the California red-legged frog continual* EPA, DWR, FWS 180 40 30 5 5 5 1 8 Implement air quality standards where poor quality is contributing to degraded conditions ongoing* EPA, FWS 270 80 80 5 5 5 1 9.1 Refine guidelines to minimize the spread of disease and parasites 1 year BRD, FWS 1.5 1.5 1 9.2 Minimize chances of spread of disease when conducting field surveys and research ongoing* MULTI 12 0.5 0.5 0.5 0.5 0.5 1 10.1 Implement site assessments and restoration programs prior to reestablishment of the frog 2 years Los Angeles Zoo, BRD, Univ, FWS TBD 1 10.2 Conduct pilot captive rearing and reestablishment programs to test methods 2 years Los Angeles Zoo, BRD, Univ, FWS, Las Virgenes Institute 500 250 250
Recovery Plan for the California Red-legged Frog 97 Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 1 10.3.1 Reestablish the frog in unoccupied core areas in Recovery unit # 1 5 years FWS, BRD, Univ 500 100 100 100 100 100 1 10.3.2 Reestablish the frog in unoccupied core areas in Recovery Unit # 2 5 years FWS, BRD, Univ 500 100 100 100 100 100 1 10.3.3 Reestablish the frog in unoccupied core areas in Recovery Unit # 8 5 years Los Angeles Zoo, FWS, Univ, Las Virgenes Institute 500 100 100 100 100 100 2 2 Develop and implement management and protection plans for all Priority 2 watersheds continual* MULTI TBD 2 6.6 Analyze past and future mitigation measures against clearly defined success criteria to determine effectiveness ongoing† FWS 18 0.75 0.75 0.75 0.75 0.75 2 6.7 Establish and maintain a database that tracks the amount of incidental take authorized and the effectiveness of mitigation measures ongoing† FWS 3.6 0.15 0.15 0.15 0.15 0.15 2 6.8 Summarize extent of incidental take previously authorized ongoing† FWS 2.4 0.1 0.1 0.1 0.1 0.1 2 6.9 Cease the use of frog barriers as a mitigation measure continual† MULTI 2 2 2 11.1 Develop a California red-legged frog survey and monitoring protocol 1 year MULTI 40 40 2 11.2.1 Conduct surveys in the Tehachapi Mountains 5 years MULTI 25 55555 2 11.2.2 Conduct surveys in the Santa Monica Mountains 5 years MULTI 25 55555
98 Recovery Plan for the California Red-legged Frog Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 2 11.2.3 Conduct surveys in the Sisquoc River Watershed 5 years MULTI 25 55555 2 11.2.4 Conduct surveys in the upper Salinas River Drainage 5 years MULTI 25 55555 2 11.2.5 Conduct surveys in the Carrizo Plain vicinity 5 years MULTI 25 55555 2 11.2.6 Conduct surveys on Bureau of Land Management lands 5 years BLM, FWS 50 10 10 10 10 10 2 11.2.7 Conduct surveys within the historic and current range in the Sierra Nevada. 5 years MULTI 50 10 10 10 10 10 2 11.2.8 Conduct surveys on all other lands identified as unsurveyed 20 years MULTI 1790 2 11.3.1 Develop a population monitoring program 1 year BRD, FWS, Univ 40 40 2 11.3.2 Conduct qualitative assessments of known populations 4 years FWS, BRD, CDPR 320 80 80 80 80 2 11.3.3 Conduct quantitative assessments of representative populations 10 years MULTI 1500 150 150 150 150 150 2 11.3.4 Researchers should provide survey data to California Department of Fish and Game and FWS ongoing† MULTI 12 0.5 0.5 0.5 0.5 0.5 2 11.3.5 Utilize monitoring results to determine where recovery should be focused 25 years FWS 120 10 10 2 11.3.6.1 Track status and recovery in Recovery Unit # 1 ongoing† FWS 120 55555
Recovery Plan for the California Red-legged Frog 99 Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 2 11.3.6.2 Track status and recovery in Recovery Unit # 2 ongoing† FWS 120 55555 2 11.3.6.3 Track status and recovery in Recovery Unit # 3 ongoing† FWS 120 55555 2 11.3.6.4 Track status and recovery in Recovery Unit # 4 ongoing† FWS 120 55555 2 11.3.6.5 Track status and recovery in Recovery Unit # 5 ongoing† FWS 120 55555 2 11.3.6.6 Track status and recovery in Recovery Unit # 6 ongoing† FWS 120 55555 2 11.3.6.7 Track status and recovery in Recovery Unit # 7 ongoing† FWS 120 55555 2 11.3.6.8 Track status and recovery in Recovery Unit # 8 ongoing† FWS 120 55555 2 11.4 Conduct population viability analyses for metapopulations 5 years BRD, Univ, FWS 25 5 5 5 2 11.5 Research metapopulation dynamics 10 years BRD, Univ, FWS 250 25 25 25 2 11.6 Conduct research to better understand the ecology of this species including use of uplands, dispersal habits, and overland movements 10 years BRD, Univ, Los Angeles Zoo, EBRPD, EBMUD, FWS 400 40 40 40 40 40 2 11.7 Investigate contaminants issues ongoing† FWS, EPA, BRD TBD 2 11.8 Conduct research on the effects of mosquitofish and determine alternatives to mosquitofish use 5 years BRD, Univ, MVCD, FWS 400 80 80 80 80 80 2 11.9 Conduct research on the ecology of exotic species 5 years BRD, Univ, FWS 100 20 20 20 20 20
100 Recovery Plan for the California Red-legged Frog Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 2 11.10 Determine genetic and ecological relationships between R. aurora draytonii and R.a.aurora 3 years Univ, BRD, FWS 90 30 30 30 2 11.11 Determine whether distinct vertebrate population segments are identifiable for the California red-legged frog 5 years BRD, FWS, Univ 150 30 30 30 30 30 2 11.12 Conduct experimental manipulations of habitat to determine requirements for creation and restoration 5 years BRD, Los Angeles Zoo, Univ, FWS, Las Virgnes Institute, TNC 100 20 20 20 20 20 2 11.13.1 Determine the effects of livestock waste 2 years BRD, NPS, FWS 40 20 20 2 11.13.2 Determine grazing thresholds that ensure optimum habitat suitability 5 years MULTI 100 20 20 20 20 20 2 11.14 Develop a protocol for a captive propagation program 2 years Los Angeles Zoo, BRD, Univ, FWS, Las Virgenes Institute 50 25 25 2 12.1 Develop and implement outreach plans 1 year FWS 40 40 2 12.2.1 Develop and implement participation plan for Recovery Unit # 1 1 year FWS 40 40 2 12.2.2 Develop and implement participation plan for Recovery Unit # 2 1 year FWS 40 40 2 12.2.3 Develop and implement participation plan for Recovery Unit # 3 1 year FWS 40 40 2 12.2.4 Develop and implement participation plan for Recovery Unit # 4 1 year FWS 40 40 2 12.2.5 Develop and implement participation plan for Recovery Unit # 5 1 year FWS 40 40
Recovery Plan for the California Red-legged Frog 101 Task Priority Implementation Schedule for the California Red-legged Frog Recovery Plan Task Number Task Description Task Duration Responsible Parties Total Costs FY1 FY2 FY3 FY4 FY5 Cost Estimate (in $1,000 units) Potential lead agencies are designated in bold. 2 12.2.6 Develop and implement participation plan for Recovery Unit # 6 1 year FWS 40 40 2 12.2.7 Develop and implement participation plan for Recovery Unit # 7 1 year FWS 40 40 2 12.2.8 Develop and implement participation plan for Recovery Unit #8 1 year FWS 40 40 2 12.3 Provide technical assistance to landowners continual† FWS 120 55555 3 3 Develop and implement a watershed management and protection plan for Priority 3 watersheds continual* MULTI TBD 3 11.15 Investigate the effects of eucalyptus on water quality 1 year NPS, GGNRA, EBRPD, BRD, FWS 20 20 3 13.1 Monitor cohabiting, native species continual† MULTI 240 10 10 10 10 10 3 13.2 Implement remediation, where appropriate continual† MULTI TBD Total estimated cost 10,031.5+ TBD costs
102 Recovery Plan for the California Red-legged Frog
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Recovery Plan for the California Red-legged Frog 111

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112 Recovery Plan for the California Red-legged Frog

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Canada. Comstock Publishing Company, Inc., Ithaca, N .Y. 640 pp.
Recovery Plan for the California Red-legged Frog 113

B. PERSONAL COMMUNICATIONS

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Christopher, S.V. 1998. University of California, Santa Barbara, California.

Fellers, G. 1999. Biological Resources Division, U.S. Geological Survey, Point Reyes National

Seashore.

Fischer, R. 2001. Biological Resources Division, U.S. Geological Survey, San Diego,

California.

Hays, L. 1998. Listing and Recovery Coordinator, U.S. Fish and Wildlife Service, Carlsbad

Fish and Wildlife Office, Carlsbad, California.

Jennings, M. 1998. Biological Resources Division, U.S. Geological Survey, Piedras Blancas

Field Station of the Western Ecological Research Center, San Simeon, California.

Larsen, S. 1998. Fish and Wildlife Biologist, U.S. Fish and Wildlife Service, Sacramento Fish

and Wildlife Office, Sacramento, California.

McLaughlin, G. 1998. Fish and Wildlife Biologist, U.S. Fish and Wildlife Service, Ventura

Fish and Wildlife Office, Ventura, California.

Padley, D. 1998. Wildlife Biologist, Santa Clara Valley Water District, San Jose, California.

Pereksta, D. 1998. Fish and Wildlife Biologist, U.S. Fish and Wildlife Service, Ventura Fish

and Wildlife Office, Ventura, California.

Rathbun, G. 1998. Biological Resources Division, U.S. Geological Survey, Piedras Blancas

Field Station of the Western Ecological Research Center, San Simeon, California.

Roberts, C. 2000. Feather River Ranger District, Plumas National Forest. Oroville, California.

Scott, N. 1998. Biological Resources Division, U.S. Geological Survey, Piedras Blancas Field

Station of the Western Ecological Research Center, San Simeon, California.

Smith, G. 1998. District Resource Ecologist, San Simeon District, California Department of

Parks and Recreation.

Strange, T. 1994. San Joaquin County Mosquito Vector Control District, Stockton, California.

Westphal, M. 1998. Coyote Creek Riparian Station, Alviso, California.
114 Recovery Plan for the California Red-legged Frog

C. IN LITT. REFERENCES

Allaback, M. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Alvarez, J. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Barry, S. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Barry, S. 1992. Letter to Marvin L. Plenert, Regional Director, U.S. Fish and Wildlife Service,

Portland, Oregon, regarding proposed listing.

Bindings, P. 2000. Letter to Wayne S. White, Field Supervisor, Sacramento Fish and Wildlife

Office, Sacramento, California, providing comments on the Draft California Red-legged

Frog Recovery Plan.

Bloom, P. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Bobzien, S. 1998. Letter to Wayne S. White, U.S. Fish and Wildlife Service, Sacramento,

California, responding to January 13, 1998, news release requesting input on recovery

needs of California red-legged frog.

Bulger, J. 1998. Wet season dispersal and habitat use by juvenile California red-legged frogs

(Rana aurora draytonii) in forest and rangeland habitats of the Santa Cruz Mountains. A

research proposal submitted to the U.S. Fish and Wildlife Service, Sacramento, California.

Christopher, S.V. 1998. Information provided to Ina Pisani regarding the status of California

red-legged frogs on Vandenberg Air Force Base, Lompoc, California.

Chubb, S. 1998. Letter to Grace McLaughlin, U.S. Fish and Wildlife Service, providing U.S.

Forest Service input for recovery plan.

Chubb, S. 1999. Letter to Ina Pisani, providing U.S. Forest Service comments on working draft

of recovery plan.

DiDonato, J. 2000. Comments to the U.S. Fish and Wildlife Service on the Draft California

Red-legged Frog Recovery Plan.

Fellers, G. 2001. Documentation of California red-legged frog in Placer County.

Fellers, G. 1998. Comments provided to Ina Pisani on a working draft of California red-legged

frog recovery plan.

Fong, D. 1998. Information on Tennessee Valley exotic predator control project conducted by

the Golden Gate National Recreation Area, National Park Service, San Francisco,

California.

Freel, K. 1998. Letter to Ina Pisani, U.S. Fish and Wildlife Service, Sacramento, California,

providing survey results from Henry Coe State Park.
Recovery Plan for the California Red-legged Frog 115

Humiston, G. 1995. California Rangeland Water Quality Management Plan.

Hunt, L. 1993. Letter to Marvin L. Plenert, Regional Director, U.S. Fish and Wildlife Service,

Portland, Oregon regarding proposed listing.

Jennings, M. 1993. Letter to Peter C. Sorensen, U.S. Fish and Wildlife Service, Sacramento,

California.

Jennings, M. 1998a. Electronic database of California red-legged frog occurrences.

Jennings, M. 1998b. Electronic message to Ina Pisani regarding the status of California redlegged frogs on Santa Cruz Island.

Jennings, M.R., M.P. Hayes, and D.C. Holland. 1992. A petition to the U.S. Fish and Wildlife

Service to place the California red-legged frog (Rana aurora draytonii) and the western

pond turtle (Clemmys marmorata) on the list of endangered and threatened wildlife and

plants. 21 pp.

Loredo, I. 1998. Electronic message to Ina Pisani regarding the status of California red-legged

frogs on National Wildlife Refuges.

Lorentzen, E. 1998. Letter to Ina Pisani providing comments on a working draft of the

California red-legged frog recovery plan.

Larsen, S. 1998. Electronic message to Ina Pisani regarding effects of coastal nurseries.

Malamud-Roam, K. 1994. Letter to Field Supervisor, Sacramento Field Office regarding the

proposed listing of the California red-legged frog as an endangered species.

McCasland, C. 1998a. Electronic message to Ina Pisani regarding the status of California redlegged frogs in Solano County.

McCasland, C. 1998b. Electronic message to Ina Pisani regarding the effects of coastal

nurseries on California red-legged frogs.

McLaughlin, G. 2000. Electronic message to Ina Pisani regarding chytrid fungus in California

red-legged frog tadpole.

Montague, P. 1998. Electronic version of Rachel’s Environment and Health Weekly.

Environmental Research Foundation.

Moore, M. and M. Westphal. 1997. Memo to Cay Goude, Chief, Endangered Species Division,

Sacramento Fish and Wildlife Office, regarding conservation strategy for the California

red-legged frog in Contra Costa and Alameda Counties.

Orlorff, S. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Rathbun, G. 1998. Comments provided to Ina Pisani on working draft of California red-legged

frog recovery plan.

_____. 1999. Comments provided to Ina Pisani on working draft of California red-legged frog

recovery plan.
116 Recovery Plan for the California Red-legged Frog

Rathbun, G. and M. Jennings. 1993. Letter to Naomi Mitchell, U.S. Fish and Wildlife Service,

Ventura Fish and Wildlife Office, Ventura, California, regarding Environmental Impact

Statement for the C.T. Ranch development.

Rathbun, G. and N. Scott. 1999. Letter to Ina Pisani regarding frog barriers.

Sasaki, T. 1999. Letter to Ina Pisani providing comments on working draft of California redlegged frog recovery plan.

Scott, N. 1998. Comments on working draft of California red-legged frog recovery plan.

Scott, N. 1999. Letter to Ina Pisani in response to a draft California red-legged frog recovery

plan.

Scott, N. and G. Rathbun. 1998. Essays provided to Ina Pisani in response to a working draft of

California red-legged frog recovery plan.

Serpa, L. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Smith, R. 2000. Electronic message to Douglas Krofta regarding status of California redlegged frogs on the Santa Rosa Plateau Reserve.

Smith, R. 2001. Electronic message to Douglas Krofta regarding status of California redlegged frogs on the Santa Rosa Plateau Reserve.

Steiner, T. 1994. Letter to Field Supervisor, Sacramento Field Office, regarding proposed

listing of California red-legged frog as an endangered species.

Strait, D. 1998. Electronic mail provided to Ina Pisani regarding the Partners for Fish and

Wildlife Program.

Swaim, K. 1994. Letter to Ms. Karen Miller, Sacramento Field Office, regarding California

red-legged frog localities.

Sweet, S. 2000. Letter to U.S. Fish and Wildlife Service providing comments on the Draft

California Red-legged Frog Recovery Plan.

Valentine, V. 1998. Letter to Ina Pisani regarding conservation programs implemented by the

California Department of Forestry and Fire Protection.

Woodburn, K. 1996. Understanding the potential impact of Garlon 4 herbicide to red-legged

frogs.
117

V. Appendices

APPENDIX A. GLOSSARY OF TECHNICAL TERMS

amplexus from Latin, an embracing; the breeding position of frogs, where the

male is on the female’s back and clasping her directly behind the front

legs or directly in front of the hind legs.

anadromous describes fish that are born in fresh water, migrate to sea, and return to

fresh water to spawn (e.g., salmon, sturgeon).

Anura the Order of tailless amphibians; frogs and toads.

aquatic of or in water; streams, lakes, rivers, ponds, and marshes are aquatic

habitats.

candidate species for which the U.S. Fish and Wildlife Service believes there is

enough information on status and threats to support a proposal for

listing.

colonization the act or process of establishing a new colony or population.

contour a practice of leaving felled trees parallel to the contour line felling

of a hillside to stabilize soils and prevent erosion.

core areas watersheds, or portions thereof, that have been determined to be

essential to the recovery of the California red-legged frog.

dispersers individual frogs, usually juveniles or subadults, that move away from

the site where they hatched and metamorphosed and settle at another

site.

diurnal active during the day.

dorsal of or pertaining to the upper surface; top or back.

dorsolateral folds ridge of skin along the region between the center of the back and the

sides.

ecotone a zone where vegetation types (such as riparian and upland) adjoin

each other and often mix.

effluent an outflow, such as waste from a sewer, or water off of agricultural

fields or streets and other developed areas.

ephemeral lasting only a short time, temporary; for aquatic habitats, water present

only part of the year.

exotic not native to the area, introduced from another region or country.
118 Recovery Plan for the California Red-legged Frog

extinct no longer existing. Can refer to a species in its entirety, or in a

particular part of the range.

extirpated extinct in a particular area.

habitat the environment in which a species or population lives and grows.

Different types of habitats may be used for different life stages.

habitat breaking up continuous habitat into smaller, isolated pieces.

fragmentation

intergrade having representative characteristics of two or more distinct groups,

such as hybrid frogs with characteristics of two subspecies or species.

interstitial the spaces between sand grains or gravel.

juvenile a newly metamorphosed frog; sometimes called froglets up to sexual

maturity at 2 to 3 years.

listed species recognized by Federal or State governments as endangered or

threatened.

maritime adjacent to the ocean, influenced by the ocean.

metamorph immature life stage with characteristics of both tadpoles and adult

frogs.

metamorphosis the process of changing from a larvae (tadpole) to an adult (frog).

metapopulation several to many subpopulations of frogs that are close enough to one

another that dispersing individuals could be exchanged.

microhabitat the smallest unit of a habitat, such as a clump of reeds that provides

cover for tadpoles, or the vegetation to which eggs are attached, or a

basking site for a frog.

morphological pertaining to body shape or structure.

nocturnal active during the night.

oviposition the act of egg-laying and/or the location where eggs are laid.

perennial for aquatic habitats, persisting all year; for plants, living more than 1

year.

point bar the inside portion of a bend in a stream or river where sand and gravel

accumulate.

population in the wider sense, all California red-legged frogs throughout their

range. In the narrower sense, used to refer to the frogs in one particular

locality or watershed; a collection of individuals that share a common

gene pool.
Recovery Plan for the California Red-legged Frog 119

posterior toward the rear or tail.

proposed species for which a proposal to list the species as threatened or

endangered has been published in the Federal Register.

Ranidae the Family of true frogs.

recovery units regions of the species’ distribution that are distinct from one another

based on ecological characteristics, status of the species, threats to the

continued existence of the species, or recovery actions needed within

the area.

riparian terrestrial areas adjacent to aquatic habitats; on the bank of a stream,

river, pond, marsh, or lake.

sink population a population whose average reproductive rate is less than its average

rate of mortality.

snout-urostyle “nose-to-tail”, the length measured from the anterior tip of the nose to

the length posterior end of the urostyle.

source population an actively breeding population that has an average birth rate that

exceeds its average death rate, and thus produces an excess of

juveniles that may disperse to other areas.

spatial of or relating to space or distribution in space, such as how ponds and

streams are distributed in a landscape.

subpopulation a group of frogs using a particular breeding site or area; several to

many subpopulations constitute a metapopulation.

taxon a level in the classification system, such as species, genus, family, or

order.

temporal of or relating to time; can be on a daily, seasonal, annual, or longer

basis.

upland terrestrial habitats not included in riparian zones, the higher elevations.

urostyle a rodlike bone composed of fused tail vertebrae present in frogs and

toads.

viability capability or capacity to survive; for populations, the ability to survive

into the foreseeable future.

vocal sac an inflatable pouch on the throat or at the sides of the neck in male

frogs.
120 Recovery Plan for the California Red-legged Frog

APPENDIX B. POTENTIAL CONTAMINANTS ASSOCIATED WITH CALIFORNIA RED-LEGGED

FROG HABITAT

The chemicals of greatest concern for which data on amphibians, fish, or their food supply

could be found are:

acephate

azinphos-methyl

carbaryl

chlorpyrifos

diazinon

dicofol

disulfoton

endosulfan

esfenvalerate

fenamiphos

glyphosate

malathion

mancozeb

methamidophos

methoprene

naled

paraquat

permethrin

phosmet

polycyclic aromatic hydrocarbons

pyrethrins

rotenone

strychnine

triclopyr

trifluralin

Units Glossary

LC50-lethal concentration to 50 percent of test organisms

mg/kg-milligrams per kilograms

mg/L-milligrams per liter

ng/L-nanongrams per liter

μg/L-micrograms per liter

PAH-Polycyclic Aromatic Hydrocarbons

Toxicity Analysis for These Chemicals

The information below, unless cited specifically, was obtained from Briggs (1992) and Moses

(1997).

Acephate is an organophosphate insecticide (classified in some sources as a carbamate) that

generally is applied as a foliar spray to control aphids. It is used on broccoli, cabbage, brussels

sprouts, cauliflower, celery, kale, leeks, lettuce, and greenhouse plants. Studies on the toxicity

of acephate to amphibians have shown effects to occur at relatively high concentrations when

compared to other organophosphates. Studies by Geen et al. (1984) determined a lethal
Recovery Plan for the California Red-legged Frog 121

concentration to 50 percent of test organisms (LC50) of 8,816,000 micrograms/liter (μg/L)

during a 4 day exposure period for the northwestern salamander (Ambystoma gracile). Studies

on the green frog (Rana clamitans) reported a LC50 of 6,433 milligrams per liter (mg)/L (U.S.

Environmental Protection Agency (1995)). Most other toxicity information on amphibians

report LC50 values above 40,000 μg/L. However, accidental spills of acephate into habitat of

the California red-legged frog could expose this species or its food base to lethal doses.

Azinphos-methyl (AZM) is an organophosphate insecticide and miticide used on fruits, nuts,

vegetables, field crops, ornamentals, and forest and shade trees. The U.S. Environmental

Protection Agency (1995) classifies this pesticide as class I, indicating high toxicity. Harris et

al. (1998) reported a green frog (Rana clamitans) 16-day LC50 of >5.0 mg/L for Guthion WP, a

preparation of 50 percent AZM. Dolah et al. (1997) reported that, in South Carolina streams,

measured concentrations of AZM at greater than 17 μg/L have coincided with documented fish

kills. They reported that at a concentration of 20 μg/L, 100 percent mortality occurs within a

short time. The use of AZM in the vicinity of the California red-legged frog could affect

recruitment and survival directly, or by affecting the food supply.

Carbaryl is a wide-spectrum carbamate insecticide, acaricide, and molluscicide used on citrus,

fruit, cotton, forests, forage crops, rangelands, lawns, nuts, ornamentals, shade trees, and other

crops, as well as on poultry, livestock, and pets. Studies on the toxicity of carbaryl to bullfrogs

have shown effects to occur at relatively high concentrations (LC50 greater than 4,000 mg/kg)

(Hudson 1984). Bioaccumulation of carbaryl can occur in catfish, crawfish, and snails, as well

as in algae and duckweed. Residue levels in fish were 140-fold greater than the concentration of

carbaryl in water. In general, due to its rapid metabolism and rapid degradation, carbaryl should

not pose a significant bioaccumulation risk in alkaline waters. However, under conditions below

neutrality, bioaccumulation may be significant (Baron 1991).

Chlorpyrifos, an organophosphate pesticide, is used in the vicinity of California red-legged

frog populations and habitats on oats, greenhouse plants, broccoli, cabbage, brussels sprouts,

cucumbers, cauliflower, kale, leeks, lettuce, parsley, radish, and berries. It is primarily a contact

poison and is available as granules, wettable powder, dustable powder, and emulsifiable

concentrate. There is insufficient information on the toxicity of chlorpyrifos to amphibians to

fully evaluate the potential effects to the species. However, studies on the toxicity of

chlorpyrifos to invertebrates have shown that relatively minor applications of the pesticide can

have dramatic lethal and sublethal effects (Delpuech et al. 1998, Odenkirchen and Eisler 1988).

Direct toxic effects to the California red-legged frog or its prey base from the application of this

pesticide are possible with standard application rates and agricultural runoff.

Diazinon is a phosphorothioate used on fruits, vegetables, forage, field crops, pasture,

rangelands, turf, and ornamentals to control soil insects and nematodes. It is also used for

household insects and fly control. Harris et al. (1998) reported a diazinon 16-day LC50 for

green frogs of 0.005±0.0001 mg/L active ingredient (a.i.). Harris also reported that Basudin®

500EC, a diazinon based pesticide, had a similar 16-day LC50 of 0.0028±0.0003 mg/L a.i. It is

apparent that diazinon is extremely toxic to amphibians, and its use should be restricted in the

vicinity of the California red-legged frog.

Dicofol is an organochlorine miticide manufactured from DDT and used on a wide variety of

fruit crops, cotton, and ornamentals. In 1986, use of dicofol was temporarily canceled by the

U.S. Environmental Protection Agency because of concerns raised by high levels of DDT

contamination. However, it was reinstated when it was shown that modern manufacturing

processes could produce technical grade dicofol containing less than 0.1 percent DDT. Dicofol

is highly toxic to fish, aquatic invertebrates, and algae (Rohm and Haas Company 1991). It

could pose a significant risk to the California red-legged frog and its prey base.
122 Recovery Plan for the California Red-legged Frog

Disulfoton is a phosphorothioate insecticide and acaricide used on cotton, sugar beets,

cabbage family crops, corn, wheat, ornamentals, cereal grains, and potatoes. It is a selective,

systemic pesticide that is especially effective against sucking insects. Disulfoton is considered

highly toxic to cold- and warm-water fish, crab, and shrimp. The LC50 values for the

compound are 0.038 mg/L in bluegill sunfish, 0.25 mg/L in guppies, 1.85 mg/L in rainbow

trout, and 6.5 mg/L in goldfish. According to the U.S. Environmental Protection Agency, the

use of disulfoton on certain crops may pose a risk to some aquatic and terrestrial endangered

species (U.S. Environmental Protection Agency 1984).

Endosulfan is a sulfur-containing organochlorine used for the control of aphids, thrips,

beetles, mites, borers, cutworms, bollworms, bugs, whiteflies, and leafhoppers on citrus, small

fruits, fiber crops, forage crops, forests, grains, nuts, oil crops, ornamentals, and vegetables.

Studies by Berrill et al. (1998) reported severe toxicity to amphibians from exposure to

endosulfan, including extensive paralysis to three different species of anuran tadpoles and high

post-exposure mortality. Two-week old tadpoles suffered greater than 50 percent mortality 4 to

19 days after exposure to a range of 0.041-0.364 mg/L endosulfan. At an exposure of 0.307

mg/L, American toad (Bufo americanus) tadpoles exhibited discoloration, swelling, and death

within 24 hours, or experienced delayed metamorphosis. Harris et al. (1998) reported that

green frogs exposed to Thiodan ® (a 47 percent mixture of endosulfan) had a 16-d LC50 of

greater than 5.0 mg/L. It is apparent that endosulfan is extremely toxic at low concentrations

to amphibians, and its use should be restricted in the vicinity of the California red-legged frog.

Esfenvalerate, a class of isomers of fenvalerate, a synthetic pyrethroid (see pyrethrin), is

used as a broad spectrum insecticide on fruits, nuts, artichokes, cabbage family crops, many

other vegetables, forests, Christmas tree farms, and recreational areas. Eisler (1992) reported

that at 4 degrees Celsius all northern leopard frogs exposed to a dose of 3 μg/L were dead

within 72 hours. These isomers of fenvalerate are reported to be the most toxic technical

mixtures, and their use in the vicinity of the California red-legged frog could have serious

negative effects.

Fenamiphos, a phosphorothioate, is used on a variety of plants including turf, citrus and other

fruit crops, some vegetables, and grains to control a wide variety of nematodes (roundworms).

The compound is absorbed by roots and is then translocated throughout the plant. The toxicity

of fenamiphos to aquatic species varies from moderate to high. Bluegill are extremely

sensitive to fenamiphos; the LC50 is 9.6 mg/L in this species. Other species tested include the

rainbow trout (LC50 is 0.11 mg/L) and goldfish (LC50 is 3.2 mg/L) (University of California

at Davis 1997a). Fenamiphos has been linked to fish and bird kills and is known to have a high

potential of leaching into the groundwater. The compound is not expected to bioaccumulate

appreciably in aquatic organisms (Smith 1993).

Glyphosate is used for control of annual and perennial plants including grasses, sedges,

broad-leaved weeds, and woody plants. It is used on range and pasture, as well as on over 150

crops. Glyphosate is also used for control of exotic species such as giant cane (Arundo donax),

and thus has a role in the rehabilitation of habitat for several native species, including the

California red-legged frog. Glyphosate does have the potential to contaminate surface waters

due to its use patterns and through erosion, as it adsorbs to soil particles suspended in runoff.

If glyphosate reached surface water, it would not be broken down readily by water or sunlight.

Toxicity tests performed under standard conditions at the Columbia National Fisheries

Laboratory indicated that this compound is “moderately toxic” to rainbow trout (U.S.

Environmental Protection Agency 1993). Some formulations may be more toxic to aquatic

species due to the different surfactants used in formulation. Although the herbicide glyphosate

appears to have limited effects on amphibians, other components of the most commonly used

formulations (e.g., Roundup®), particularly the surfactants, have severe negative effects on
Recovery Plan for the California Red-legged Frog 123

amphibians. Formulations of glyphosate must be used carefully in and near California redlegged frog habitat.

Malathion is a nonsystemic, wide-spectrum organophosphate insecticide used for the control

of mosquitos, sucking and chewing insects on fruits and vegetables, flies, household insects,

animal parasites (ectoparasites), and head and body lice. Malathion is used in formulations

with many other pesticides. It is highly toxic to aquatic invertebrates with EC50 values from 1

μg/L to 1 mg/L (Johnson and Finley 1980), and to the aquatic stages of amphibians (U.S.

Environmental Protection Agency 1992). Malathion has a wide range of toxicities in fish, from

very highly toxic in walleye (96-hour LC50 of 0.06 mg/L) to slightly toxic in goldfish (10.7

mg/L) (Johnson and Finley 1980). Malathion could affect California red-legged frog

populations through direct mortality and by reducing the prey base.

Mancozeb is a carbamate fungicide used on field crops, fruits, vegetables, nuts, and

commercial sod farms. Harris et al. (1998) reported that green frog embryos exposed to

Dithane DG® (76 to 80 percent mancozeb) had zero percent hatching success at approximately

1.0 to 20 mg/L. Adult frogs exhibited a 16-day LC50 of 0.20±0.04 mg(a.i.)/L. Mancozeb

appears to be quite toxic to amphibians. Its use should be restricted in the vicinity of the

California red-legged frog.

Methamidophos is a highly active, systemic, residual, organophosphate insecticide and

acaricide used to control aphids, flea beetles, whiteflies, thrips, cabbage loopers, Colorado

potato beetles, potato tubeworms, armyworms, mites, leafhoppers, and many others. Crop uses

include broccoli, brussels sprouts, cauliflower, grapes, celery, sugar beets, cotton, and potatoes.

This compound is considered to be highly toxic to mammals, birds, and bees (U.S.

Environmental Protection Agency 1997a) and is also toxic to aquatic organisms. The LC50

ranges from 25 to 100 mg/l in 96-hour tests with rainbow trout, guppies, carp, and goldfish.

Freshwater, estuarine, and marine crustaceans are extremely sensitive to methamidophos.

Concentrations as low as 0.22 ng/L (nanograms/liter) (0.00000022 mg/l) were lethal to larval

crustaceans in 96-hour toxicity tests.

Methoprene is an insect growth regulator. It is considered a biochemical pesticide because,

rather than controlling target pests through direct toxicity, methoprene interferes with an

insect’s life cycle and prevents it from reaching maturity or reproducing. Methoprene is used in

the production of a number of foods including meat, milk, eggs, mushrooms, peanuts, rice, and

cereals. It is also used in aquatic areas to control mosquitos and several types of flies, moths,

beetles, and fleas. Studies on other amphibians suggest that use of this chemical may pose a

threat. Although methoprene did not cause increased mortality of gray treefrog tadpoles (Hyla

versicolor), it has been implicated in reduced survival rates and malformations in the

development of northern leopard frogs (Rana pipiens) (Ankley et al. 1998). According to the

U.S. Environmental Protection Agency (1991), methoprene is highly and acutely toxic to

estuarine invertebrates, and ecological effects studies suggest that use of the briquette or slowrelease formulation in estuarine areas may cause disruption of normal ecological processes. In

addition, the U.S. Environmental Protection Agency states in their fact sheets that methoprene

is moderately toxic to warm water, freshwater fish, and is slightly toxic to cold water,

freshwater fish. Mosquito and Vector Control Districts typically use dosages far below those

found to cause developmental problems and mortality (P. Bindings in litt. 2000).

Naled, an organophosphate pesticide, is used on greenhouse plants, broccoli, cabbage, brussels

sprouts, kale, leeks, lettuce, and radishes. It is used to control aphids, mites, mosquitos, and

flies. As an organophosphate pesticide it is assumed naled is toxic to aquatic organisms and

caution should be exercised when using it in the vicinity of California red-legged frog habitats.
124 Recovery Plan for the California Red-legged Frog

Paraquat is a herbicide widely used for broadleaf weed control. It has been employed for

killing marijuana in the U.S. and in Mexico. It is also used as a crop desiccant and defoliant,

and as an aquatic herbicide. Paraquat is considered to be slightly to moderately toxic to many

species of aquatic life, including rainbow trout, bluegill, and channel catfish (U.S.

Environmental Protection Agency 1997b). Eisler (1990) reported that concentrations as low as

0.5 mg/kg had an adverse effect on northern leopard frog tadpoles. These effects included a

high number of tail abnormalities, reduced growth rate, abnormal swimming behavior, and

increased mortality. In 15-day old northern leopard frog tadpoles, 95 percent of the test

organisms were dead after 6 days when exposed to 2 mg/kg paraquat. In addition to potential

adverse effects on tadpoles, there may be an adverse effect on the California red-legged frog by

reduction of plant cover.

Permethrin, a pyrethroid pesticide, is used on berries, broccoli, cabbage, brussels sprouts,

greenhouse plants, kale, leeks, lettuce, and radishes. It is also used to control animal

ectoparasites, biting flies, and cockroaches. It is available in dusts, emulsifiable concentrates,

smokes, ultra-low volume sprays, and wettable powder formulations. There is insufficient

information on toxicity of permethrin to amphibians. Toxicity studies on invertebrates have

shown that permethrin contaminated sediments are toxic to chironomid larvae (Fleming et al.

1998). Studies conducted on adult desert pupfish (Cyprinodon macularius) have shown a 48-

hour LC50 of 0.005 mg/L of permethrin (Mulla et al. 1978). Standard applications of

permethrin and agricultural runoff may cause direct acute effects to the California red-legged

frog or its prey base.

Phosmet is a non-systemic, organophosphate insecticide used on both plants and animals. It is

mainly used on apple trees for control of codling moths; it is also used on a wide range of fruit

crops, ornamentals, and vines for the control of aphids, mites, and fruit flies. The reported 96-

hour LC50 values for phosmet are less than 1 mg/L in bluegill, small- and largemouth bass,

rainbow trout, and chinook salmon, and are less than 10 mg/L in fathead minnow and channel

catfish (Johnson and Finley 1980). The compound is also very highly toxic to aquatic

invertebrates (Johnson and Finley 1980). Phosmet has little potential for accumulation in

aquatic organisms. Phosmet could have direct toxic effects on the California red-legged frog

and indirect effects through reduction of the prey base.

Polycyclic Aromatic Hydrocarbons, or PAHs, are among the most potent carcinogens known

to exist. However, amphibians are considered to be quite resistant to PAH carcinogens when

compared to mammals. PAHs are widely distributed in the environment and have been detected

in plant and animal tissues, sediments, soils, air, surface water, and groundwater (Eisler 1987).

PAHs may enter the aquatic environment through industrial and domestic discharge, surface

runoff, and releases of petroleum products into water bodies. PAHs can cause a wide variety of

adverse biological effects, including effects on survival, growth, metabolism, and tumor

formation (Eisler 1987). Eisler (1987) reports that 85 percent of adult African clawed frogs

exposed to 1.5 mg benzo(a)pyrene, a PAH, developed lymphosarcomas (cancer of connective

tissues associated with the lymphatic system) in 85 to 288 days. When leopard frogs were

exposed to a single dose of 3-methylcholanthrene, another PAH, at 40 mg/kg body weight,

cellular function and blood and tissue oxygen levels were abnormal for several weeks. Hatch

and Burton (1998) suggested that low levels of PAHs may act with other environmental factors

to cause adverse effects to larval amphibians.

Pyrethrins are natural insecticides produced by certain species of chrysanthemums; synthetic

pyrethrins also are manufactured. The compounds may be used in grain storage and in poultry

pens, and on dogs and cats to control lice and fleas. Both natural and synthetic compounds are

extremely toxic to aquatic life, such as bluegill and lake trout, and slightly toxic to bird

species, such as mallards. Toxicity increases with higher water temperatures and acidity.
Recovery Plan for the California Red-legged Frog 125

Natural pyrethrins are highly fat soluble, but are easily degraded and thus do not accumulate

in the body. Although no information regarding the toxicity of natural pyrethrins to

amphibians was found, effects may be similar (see esfenvalerate).

Rotenone is the dried and ground root of various plants, or extracts thereof. It is used for fish

eradications as part of water body management, in home gardens for insect control, and for

lice and tick control on pets. Rotenone interferes with normal cell functions and nerve

transmission and is highly toxic to fish and amphibians. Reported 96-hour LC50s were 0.031

mg/L in rainbow trout, 0.0026 mg/L in channel catfish, and 0.023 mg/L in bluegill for the 44

percent pure formulation (Johnson and Finley 1980). Aquatic invertebrates have a wide range

of sensitivity to rotenone with 48-hour EC50 values ranging from 0.002 to 100 mg/L (Johnson

and Finley 1980). The compound is not expected to accumulate appreciably in aquatic

organisms as its highly toxic nature allows little survival of the organisms in which it would

accumulate. Contamination of breeding ponds with rotenone could cause the loss of an entire

year’s production of California red-legged frog larvae.

Strychnine is currently registered for use only below-ground as a bait application to control

pocket gophers, but was used in the U.S. to control vertebrate animals for many years before

1947. Strychnine ranges from moderately to highly toxic to freshwater fish and is moderately

toxic to aquatic invertebrates (Environmental Protection Agency 1998). The U.S.

Environmental Protection Agency believes that the risks to non-target terrestrial animals are

minimal when strychnine is used below-ground and that below-ground use of strychnine does

not constitute a risk to non-target or endangered species. However, this does not take into

account any burrowing species or those that may use small mammal burrows as temporary

refuges.

Triclopyr, a pyridine, is a selective systemic herbicide used for control of woody and

broadleaf plants along rights-of-way, in forests, on industrial lands, and on grasslands and

parklands. Studies on the toxicity of triclopyr to aquatic organisms have shown that the parent

compound of this pesticide is practically nontoxic to fish, with a LC50 (96-hour) of 117 mg/L

in rainbow trout and 148 mg/L in bluegill sunfish (University of California at Davis 1997b).

The compound has little if any potential to accumulate in aquatic organisms. In addition to the

potential direct effects of the ester formulation of this herbicide on amphibians, there may be

an adverse effect on the California red-legged frog by reduction of plant cover.

Trifluralin is a selective, pre-emergence dinitroaniline herbicide used to control many annual

grasses and broadleaf weeds in lawns and in a large variety of fruit, nut, vegetable, and grain

crops, including soybeans, sunflowers, cotton, and alfalfa. Trifluralin is highly toxic to fish,

amphibians, and other aquatic organisms. The 96-hour LC50 is 0.02 to 0.07 mg/L in rainbow

trout and bluegill (Johnson et al. 1980). Variables such as temperature, pH, life stage, and size

may affect the toxicity of the compound. Trifluralin is highly toxic to Daphnia, with a 48-hour

LC50 of 0.5 to 0.6 mg/L. The compound shows a moderate tendency to accumulate in aquatic

organisms (U.S. Environmental Protection Agency 1996).

Other contaminants

Ammonia: Harris et al. (1998) reported that elevated levels of ammonia could act as an

environmental stressor to amphibians and could lead to decreased hatching success, survival,

or growth rates.
126 Recovery Plan for the California Red-legged Frog

CONTAMINANTS GLOSSARY

acaricide compound used to kill ticks and mites.

acute toxicity the ability to cause a poisonous effect or death as a result of a shortterm or single exposure. Common acute effects are skin or eye

irritation, vomiting, tremors.

bioaccumulate increase in concentration in living organisms as they breathe

contaminated air, drink contaminated water, or eat contaminated food.

carbamate organic compounds based on carbamic acid (CO2

NH3); cholinesterase

inhibitors, they interfere with nerve function, cause malformations in

developing embryos, and are suspected carcinogens.

carcinogen cancer-causing agent.

cholinesterase a neurotransmitter; cholinesterase inhibitors interfere with the

transmission of nerve impulses. Symptoms of cholinesterase inhibition

include nausea, vomiting, cramps, increased heart rate, and death.

chronic toxicity the ability to cause a poisonous effect or death as a result of long-term

exposure. Liver or kidney damage, impaired reproduction, and cancers

are common chronic effects.

dinitroaniline herbicides; in animals, they interfere with cell function, cause skin and

eye irritation, and are carcinogenic and teratogenic.

fungicide compound used to kill fungi.

herbicide compound used to kill plants.

insecticide compound used to kill insects.

miticide compound used to kill mites.

molluscicide a compound used to kill molluscs (snails, slugs, clams, etc.).

organochlorine chlorinated hydrocarbons; compounds that contain, carbon, hydrogen,

and chlorine, such as DDT; interfere with transmission of nerve

impulses primarily in the central nervous system (brain and spinal

cord); bioaccumulate, carcinogens, suspected teratogens and

mutagens; can travel long distances through air and groundwater.

organophosphate compounds that contain, carbon, hydrogen, and phosphorus;

cholinesterase inhibitors, they interfere with nerve function, cause

malformations in developing embryos, and are suspected carcinogens.

pesticide a general term for compounds used to kill organisms considered pests,

including slugs, nematodes, insects, mites, rodents, birds, and plants.

phosphorothioate a class of organophosphates that also contain sulfur.
Recovery Plan for the California Red-legged Frog 127

pyrethroids natural compounds derived from chrysanthemums, or synthetic

compounds that mimic their structure and function. Pyrethroids block

nerve impulse transmission, affect hormone metabolism, and affect the

immune system. They are suspected carcinogens, mutagens, and

teratogens.

pyridine herbicide; limited information available.

systemic absorbed by the leaves or roots and then translocated throughout the

plant. Systemic pesticides are particularly effective against sucking

insects and mites.

teratogen a substance that causes malformations in developing embryos.
128 Recovery Plan for the California Red-legged Frog

LITERATURE CITED FOR APPENDIX B

Ankley, G.T., J.E. Tietge, D.L. DeFoe, K.M. Jensen, G.W. Holcombe, E.J. Durhan, S. A.

Diamond, and P.K. Schoff. 1998. Effects of methoprene and UV light on survival and

development of Rana pipiens. http:// www.mpm.edu/collect/vertzo/herp/Daptf/

Mwabst.html

Baron, R. L. 1991. Carbamate insecticides. Pp. 3-6. In Handbook of pesticide toxicology.

Hayes, W. J., Jr. and E. R., Laws, Jr., (eds). Academic Press, New York, NY.

Berrill, M., D. Coulson, L. McGillivray, and B. Pauli. 1998. Toxicity of endosulfan to aquatic

stages of anuran amphibians. Environmental Toxicology and Chemistry 17:1738-1744.

Bindings, P. 2000. Letter from Santa Cruz Mosquito and Vector Control District to U.S. Fish

and Wildlife Service.

Briggs, S. 1992. Basic guide to pesticides: their characteristics and hazards. The Rachel Carson

Council, Taylor and Francis, Washington, D.C. 283 pp.

Delpuech, J. M., B. Froment, P. Fouillet, F. Pompanon, S. Janillon, and M. Bouletreau. 1998.

Inhibition of sex pheromone communications of Trichogramma brassicae (Hymenoptera)

by the insecticide chlorpyrifos. Environmental Toxicology and Chemistry 17:1107-1113.

Dolah, R. F. Van, P. P. Maier, M. H. Fulton, and G. I. Scott. 1997. Comparison of

azinphosmethyl toxicity to juvenile red drum (Sciaenops ocellatus) and the mummichog

(Fundulus heteroclitus). Environmental Toxicology and Chemistry 16:1488-1493.

Eisler, R. 1987. Polycyclic aromatic hydrocarbon hazards to fish, wildlife, and invertebrates: A

synoptic review. Contaminant Hazard Reviews Report No. 11. Patuxent Wildlife Research

Center, U.S. Fish and Wildlife Service. 81 pp.

_____. 1990. Paraquat hazards to fish, wildlife, and invertebrates: A synoptic review.

Contaminant Hazard Reviews Report No. 22. Patuxent Wildlife Research Center, U.S.

Fish and Wildlife Service. 28 pp.

 _____. 1992. Fenvalerate hazards to fish, wildlife, and invertebrates: a synoptic review.

Contaminant Hazard Reviews Report No. 24. Patuxent Wildlife Research Center, U.S.

Fish and Wildlife Service. 43pp.

Fleming, R. J., D. Holmes, and S. J. Nixon. 1998. Toxicity of permethrin to Chironomus

riparius in artificial and natural sediments. Environmental Toxicology and Chemistry

17:1332-1337.

Geen, G. H., B. A. McKeown, T. A. Watson, and D. B. Parker. 1984. Effects of acephate

(Orthene) on development and survival of the salamander, Ambystoma gracile (Baird).

Journal of Environmental Science and Health B19(2):157-170.

Harris, M. L., C. S. Bishop, J. Struger, B. Ripley, and J. P. Bogart. 1998. The functional

integrity of northern leopard frog (Rana pipiens) and green frog (Rana clamitans)

populations in orchard wetlands. II. Effects of pesticides and eutrophic conditions on early

life stage development. Environmental Toxicology and Chemistry 17(7): 1351-1363.
Recovery Plan for the California Red-legged Frog 129

Hatch, A. C. and G. A. Burton, Jr. 1998. Effects of photoinduced toxicity of fluoranthene an

amphibian embryos and larvae. Environmental Toxicology and Chemistry 17: 1777-1785.

Hudson, R. H. 1984. Handbook of toxicity of pesticides to wildlife. U.S. Fish and Wildlife

Service Resource Publication Number 153.

Johnson, W.W. and M.T. Finley. 1980. Handbook of acute toxicity of chemicals to fish and

aquatic invertebrates. Resource Publication 137. U.S. Department of Interior, Fish and

Wildlife Service, Washington, DC.

Moses, L., editor. 1997. Farm chemicals handbook ‘97. Meister Publishing Company,

Willoughby, Ohio. 943 pp.

Mulla, M.S., H.A. Navvab-Gojrati, and J.A. Darwazeh. 1978. Toxicity of mosquito larvicidal

pyrethroids to four species of freshwater fishes. Environmental Entomology 7:428-430.

Odenkirchen, E.W. and R. Eisler. 1988. Chlorpyrifos hazards to fish, wildlife, and

invertebrates: A synoptic review. Contaminant Hazard Reviews Report No. 13. Patuxent

Wildlife Research Center, U.S. Fish and Wildlife Service. 34 pp.

Rohm and Haas Company. 1991. Material safety data sheet for Kelthane Technical B Miticide.

Philadelphia, PA.

Smith, G. J. 1993. Toxicology and pesticide use in relation to wildlife: Organophosphorus and

carbamate compounds. C. K. Smoley, Boca Raton, FL.

U.S. Environmental Protection Agency, Office of Pesticides and Toxic Substances. 1984.

Pesticide fact sheet number 43: Disulfoton. Washington, D.C.

_____. 1991. Pesticide reregistration fact sheets: Methoprene. Washington D.C.

_____. 1992. Pesticide reregistration fact sheets: Malathion. Washington D.C.

_____. 1993. Pesticide reregistration fact sheets: Glyphosate. Washington D.C.

_____. 1995. Environmental effects database. Washington, D.C.

_____. 1996. Pesticide reregistration fact sheets: Trifluralin. Washington D.C.

_____. 1997a. Pesticide reregistration fact sheets: Methamidophos. Washington D.C.

_____. 1997b. Pesticide reregistration fact sheets: Paraquat. Washington D.C.

_____. 1998. Pesticide reregistration fact sheets: Strychnine. Washington D.C.

University of California, Davis. 1997a. Pesticide Use Profiles: Fenamiphos. Davis, California.

_____. 1997b. Pesticide Use Profiles: Trifluralin. Davis, California.

Appendix C. Maps of Core Areas Per County
130 Recovery Plan for the California Red-legged Frog

APPENDIX C. MAPS OF CORE AREAS PER COUNTY

The following core are maps were developed using the California Watershed Map (Calwater

Version 2.2). This is a set of standardized watershed boundaries meeting standardized

delineation critera. The hierachy of watershed designations consists of six levels of increasing

specificity: Hydrologic Region, Hydrologic Unit, Hydrologic Area, Hydrologic Sub-Area,

Super Planning Watershed, and Planning Watershed. Core area maps were delineated at the

Hydrologic Sub-Area level. Following each core area map is a list of Hydrologic Sub-Areas

that are included in each map per core area.

Figure 13. Map of core areas in Butte, Plumas, and Yuba Counties ..................................... 131

Figure 14. Map of core areas in Calaveras County .............................................................. .132

Figure 15. Map of core areas in Sacramento, El Dorado, and Amador Counties ................. 133

Figure 16. Map of core areas in Tuolumne and Mariposa Counties ..................................... 134

Figure 17. Map of core areas in Shasta and Tehama Counties .............................................. 135

Figure 18. Map of core areas in Lake and Colusa Counties .................................................. 136

Figure 19. Map of core areas in Napa, Solano, and Yolo Counties ....................................... 137

Figure 20. Map of core areas in Marin and Sonoma Counties .............................................. 138

Figure 21. Map of core areas in Alameda, San Joaquin and Contra Costa Counties ............ 139

Figure 22. Map of core areas in Santa Clara and Stanislaus Counties .................................. 140

Figure 23. Map of core areas in San Mateo County .............................................................. 141

Figure 24. Map of core areas in Santa Cruz County ............................................................. 142

Figure 25. Map of core areas in Monterey, San Benito, and Fresno Counties ...................... 143

Figure 26. Map of core areas in San Luis Obispo and Kern Counties .................................. 144

Figure 27. Map of core areas in Merced County ................................................................... 145

Figure 28. Map of core areas in Santa Barbara County ........................................................ 146

Figure 29. Map of core areas in Los Angeles, Ventura, and Orange Counties ...................... 147

Figure 30. Map of core areas in San Bernardino County ...................................................... 149

Figure 31. Map of core areas in San Diego and Riverside Counties ..................................... 150
Recovery Plan for the California Red-legged Frog 131

Figure 13. Map of

core areas in Butte,

Plumas, and Yuba

Counties.

Butte County

Core Area:

Feather River

Hydrologic Sub-Area:

Bucks Lake

Reservoir Drain

Core Area:

Yuba River–S. Fork

Feather River

Hydrologic Sub-Area:

Bullards Bar

Lumpkin

Plumas County

Core Area:

Feather River

Hydrologic Sub-Area:

Bucks Lake

Butt Valley

Reservoir Drain

Core Area:

Yuba River–S. Fork

Feather River

Hydrologic Sub-Area:

Lumpkin

Yuba County

Core Area:

Yuba River–S. Fork

Feather River

Hydrologic Sub-Area:

Bullards Bar

Lumpkin
132 Recovery Plan for the California Red-legged Frog

Figure 14. Map of

core areas in

Calaveras County

Calaveras County

Core Area:

South Fork Calaveras

River

HSA:

South Fork Calaveras
Recovery Plan for the California Red-legged Frog 133

Figure 15. Map of

core areas in

Sacramento, El

Dorado, and

Amador Counties

Sacramento

County

Core Area:

Cosumnes River

Hydrologic Sub-Area:

Big Canyon Creek

Upper Deer Creek

El Dorado County

Core Area:

Cosumnes River

Hydrologic Sub-Area:

Big Canyon Creek

North Fork Cosumnes

Omo Ranch

Upper Deer Creek

Weber Creek

Core Area:

Traverse Crek

HSA:

Coloma

Amador County

Core Area:

Cosumnes River

Hydrologic Sub-Area:

Big Canyon Creek

North Fork Cosumnes

Omo Ranch
134 Recovery Plan for the California Red-legged Frog

Figure 16. Map of

core areas in Tuolumne and

Mariposa Counties Tuolumne County

Core Area:

Piney Creek

HSA:

Coulterville

Core Area: Tuolumne River

Hydrologic Sub-Area:

Cherry Lake

Clavey River

Hetch Hetchy

Lake Eleanor

Mercut Peak

North Fork Merced

Mariposa County

Core Area:

Piney Creek

HSA:

Coulterville

Core Area: Tuolumne River

Hydrologic Sub-Area:

Clavey River

North Fork MErced
Recovery Plan for the California Red-legged Frog 135

Figure 17. Map of

core areas in Shasta

and Tehama

Counties

Shasta County

Core Area:

Cottonwood Creek

HSA:

Lower Cottonwood

Tehama County

Core Area:

Cottonwood Creek

Hydrologic Sub-Area:

Elder Creek

Lower Cottonwood

Red Bank Creek

South Fork

Wells Creek
136 Recovery Plan for the California Red-legged Frog

Figure 18. Map of

core areas in Lake

and Colusa Counties

Lake County

Core Area:

Putah Creek–Cache

Creek

HSAs

Lakeport

Lower Lake

Pope Creek

Upper Putah Creek

Wilson Valley

Colusa County

Core Area:

Putah Creek–Cache

Creek

Hydrologic Sub-Area:

East Blue Ridge

Rumsey

Wilson Valley
Recovery Plan for the California Red-legged Frog 137

Figure 19. Map of

core areas in Napa,

Solano, and Yolo

Counties

Napa County

Core Area:

Jameson Canyon–

Lower Napa River

Hydrologic Sub-Area:

Benicia

Napa River

Core Area:

Lake Berryessa Tributaries

Hydrologic Sub-Area:

Capell Creek

East Rocky Ridge

Core Area:

Putah Creek–Cache

Creek

Hydrologic Sub-Area:

East Blue Ridge

Eticuera Creek

Pope Creek

Rumsey

Upper Puah Creek

Wilson Valley

Solano County

Core Area:

Jameson Canyon–

Lower Napa River

Hydrologic Sub-Area:

Benicia

Napa River

Core Area:

Lake Berryessa Tributaries

Hydrologic Sub-Area:

Capell Creek

East Rocky Ridge Yolo County

Core Area:

Lake Berryessa Tributaries

HSA:

East Rocky Ridge

Core Area:

Putah Creek–Cache

Creek

Hydrologic Sub-Area:

East Blue Ridge

Eticuera Creek

Rumsey

Upper Putah Crek

Wilson Valley
138 Recovery Plan for the California Red-legged Frog

Figure 20. Map of

core areas in Marin

and Sonoma

Counties

Marin County

Core Area:

Belvedere Lagoon

HSA:

San Rafael

Core Area:

Petaluma Creek–

Sonoma Creek

HSA:

Petaluma River

Core Area:

Pt. Reyes Peninsula

Hydrologic Sub-Area:

Bolinas

Inverness

Lagunitas Creek

Point Reyes Walker Creek

Sonoma County

Core Area:

Petaluma Creek–

Sonoma Creek

Hydrologic Sub-Area:

Petaluma River

Sonoma Creek

Core Area:

Pt. Reyes Peninsula

HSA: Walker Creek

Core Area:

Putah Creek–Cache

Creek

Hydrologic Sub-Area:

Lakeport

Upper Putah Creek

Core Area:

Upper Sonoma Creek

HSA:

Sonoma Creek
Recovery Plan for the California Red-legged Frog 139

Figure 21. Map of

core areas in

Alameda, San

Joaquin and Contra

Costa Counties

Alameda County

Core Area:

East San Francisco

Bay

Hydrologic Sub-Area:

Alameda Creek

East Bay Cities

North Diablo Range

Contra Costa

County

Core Area:

East San Francisco

Bay

Hydrologic Sub-Area:

Alameda Creek

East Bay Cities

North Diablo Range

Pittsburg Walnut Creek
140 Recovery Plan for the California Red-legged Frog

Figure 22. Map of

core areas in Santa

Clara and Stanislaus

Counties

Santa Clara County

Core Area:

East San Francisco Bay

Hydrologic Sub-Area:

Alameda Creek

Coyote Creek

Orestimba Creek

Pacheco-Santa Ana

Creek

Romero Creek

Core Area:

Salinas River–Pajaro

River

Hydrologic Sub-Area:

Aptos–Soquel

Santa Cruz Mountains

Core Area:

Santa Clara Valley

Hydrologic Sub-Area:

Santa Cruz Mountains

South Santa Clara

Valley

Core Area:

South San Francisco

Bay

Hydrologic Sub-Area:

Palo Alto

Pescadero Creek

Stanislaus County

Core Area:

East San Francisco Bay

Hydrologic Sub-Area:

Alameda Creek

Coyote Creek

Orestimba Creek

Pacheco–Santa Ana

Creek

Romero Creek
Recovery Plan for the California Red-legged Frog 141

Figure 23. Map of

core areas in San

Mateo County

San Mateo County

Core Area:

South San Francisco

Bay

Hydrologic Sub-Area:

Ano Nuevo

Davenport

Half Moon Bay

Pacfica

Palo Alto

Pescadero Creek

San Gregorio Creek

San Mateo Bayside

Tunitas Crek
142 Recovery Plan for the California Red-legged Frog

Figure 24. Map of

core areas in Santa

Cruz County

Santa Cruz County

Core Area:

Watsonville Slough–

Elkhorn Slough

Hydrologic Sub-Area:

Aptos–Soquel

Santa Cruz Mountains

Watsonville

Core Area:

South San Francisco

Bay

Hydrologic Sub-Area:

Ano Nuevo

Davenport

Pescadero Creek
Recovery Plan for the California Red-legged Frog 143

Monterey County

Core Area:

Carmel River–Santa

Lucia

Hydrologic Sub-Area:

Carmel River

Santa Lucia

Core Area:

Estrella River

HSA: Estrella River

Core Area:

Gabilan Range

Hydrologic Sub-Area:

Gabilan Range

Core Area:

Watsonville Slough–

Elkhorn Slough

Hydrologic Sub-Area:

Bolsa Neuva

Chualar

Moro Cojo

Neponset

Watsonville

San Benito County

Core Area:

East San Francisco Bay

Hydrologic Sub-Area:

Pacheco–Santa Ana

Creek

Panoche

San Benito River

Core Area:

Gabilan Range

Hydrologic Sub-Area:

Gabilan Range

Core Area:

Salinas River–Pajaro

River

Hydrologic Sub-Area:

Bolsa Neuva

Santa Cruz Mountains

Watsonville

Core Area:

Santa Clara Valley

Hydrologic Sub-Area:

Santa Cruz Mountains

S. Santa Clara Valley

Fresno County

Core Area:

East San Francisco Bay

Hydrologic Sub-Area:

Panoche

Core Area:

Estrella River

HSA: Estrella River

Figure 25. Map of core areas in Monterey, San Benito,

and Fresno Counties
144 Recovery Plan for the California Red-legged Frog

Figure 26. Map of

core areas in San

Luis Obispo and

Kern Counties

San Luis Obispo

County

Core Area:

Arroyo Grande Creek

HSA:

Oceano

Core Area:

Estero Bay

Hydrologic Sub-Area:

Arroyo De La Cruz

Cayucos

Chorro

Los Osos

Morro

Old

San Luis Obispo Creek

San Simeon

Santa Rosa Toro Villa

Core Area:

Estrella River

Hydrologic Sub-Area:

Estrella River Temblor

Core Area:

Santa Maria River–

Santa Ynez River

HSA:

Guadalupe

Core Area:

Sisquoc River

HSA:

Sisquoc

Kern County

Core Area:

Estrella River

Hydrologic Sub-Area:

Estrella River Temblor
Recovery Plan for the California Red-legged Frog 145

Figure 27. Map of

core areas in Merced

County

Merced County

Core Area:

East San Francisco

Bay

Hydrologic Sub-Area:

Pacheco–Santa Ana

Creek

Romero Creek

San Benito River

San Luis Reservoir
146 Recovery Plan for the California Red-legged Frog

Figure 28. Map of

core areas in Santa

Barbara County

Santa Barbara

County

Core Area:

Santa Maria River–

Santa Ynez River

Hydrologic Sub-Area:

Arguello

Buellton

Guadalupe

Lake Cachuma

Lompoc

Los Olivos

San Antonio

Santa Cruz Creek

Santa Rita

Core Area:

Sisquoc River

HSA:

Sisquoc

Core Area: Ventura River–Santa

Clara River

Hydrologic Sub-Area: Topa Topa

Upper Ventura River
Recovery Plan for the California Red-legged Frog 147

Figure 29 . Map of

core areas in Los

Angeles, Ventura,

and Orange Counties

(see next page for Core

Areas and HSAs)
148 Recovery Plan for the California Red-legged Frog

Los Angeles

County

Core Area:

San Gabriel Mountain

Hydrologic Sub-Area:

Santa Anita

Tujunga

Upper Canyon

Core Area:

Santa Monica Boy–

Ventura Coastal

Hydrologic Sub-Area:

Arroyo Senuit

Carbon Canyon

CorralCanyon

Encinal Canyon

Escondido Canyon

La Virgenes Canyon

Las Flores Canyon

Latigo Canyon

Lindero Canon

Little Sycamore Canyon

Los Alisos Canyon

Monte Nido

Nicholas Canyon

Pena Canyon

Piedra Gorda Canyon

Ramera Canyon

Russell Valley

Sherwood

Solstice Canyon

Topanga Canyon

Trancas Canyon

Triunfo Canyon

Tuna Canyon

Zuma Canyon

Core Area:

Ventura River–Santa

Clara River

HSA:

Upper Piru

Ventura County

Core Area:

Santa Maria River–

Santa Ynez River

HSA:

Santa Cruz Creek

Core Area:

Santa Monica Bay–

Ventura Coastal

Hydrologic Sub-Area:

Arroyo Senuit

Big Sycamore Canyon

Deer Canyon

La Jolla Valley

La Virgenes Canyon

Lindero Canyon

Little Sycamore Canyon

Russell Valley

Sherwood

Core Area:

Ventura River–Santa

Clara River

Hydrologic Sub-Area:

Lower Ventura River

Ojai Valley

Sisar Topa Topa

Upper Ojai

Upper Piru

Upper Ventura River

Orange County

Core Area:

Santa Ana Mountain

HSA:

Santiago

Core Area:

Santa Rosa Plateau

HSA:

Upper San Juan
Recovery Plan for the California Red-legged Frog 149

Figure 30. Map of

core areas in San

Bernardino County

San Bernardino

County

Core Area:

Forks of the Mojave

HSA:

Upper Mojave
150 Recovery Plan for the California Red-legged Frog

Figure 31. Map of

core areas in San

Diego and Riverside

Counties

San Diego County

Core Area:

Laguna Mountain

Hydrologic Sub-Area:

Cottonwood

Pine

Core Area:

San Luis Rey

Hydrologic Sub-Area:

Guejito

Pala

Pauma

Core Area:

Santa Rosa Plateau

Hydrologic Sub-Area:

Deluz Creek

Gavilan

San Mateo Canyon

Core Area:

Sweetwater

Hydrologic Sub-Area:

Jamacha

Loveland

Riverside County

Core Area:

San Luis Rey

HSA:

Pala

Core Area:

Santa Ana Mountain

HSA:

Santiago

Core Area:

Santa rosa Plateau

Hydrologic Sub-Area:

Deluz Creek

Gavilan

Murrieta

San Mateo Canyon

Upper San Juan
Recovery Plan for the California Red-legged Frog 151

APPENDIX D. GUIDELINES FOR VOLUNTARY POND MANAGEMENT

FOR THE BENEFIT OF THE CALIFORNIA RED-LEGGED FROG

In many California red-legged frog metapopulations, artificial ponds maintained for watering

livestock are the principal sources of the young frogs that annually repopulate the system. In

dry areas, a pond can represent a longer-lasting water source, providing for complete tadpole

development and adult escape cover. At wetter sites, ponds are often the only quiet water

refuges for egg-laying and tadpole development outside of the swiftly flowing streams. In both

cases, ponds can give a stability and predictability to the habitats that would not otherwise be

present.

However, in some cases, ponds can be extremely detrimental to the California red-legged frog.

Perhaps the most common nuisance pond is one that attracts and provides habitat for bullfrogs

and predatory fish. In many instances, these predators eliminate the California red-legged frog.

Another type of detrimental pond is one that fills and is attractive breeding habitat in late

winter and early spring, but dries up before tadpoles can undergo metamorphosis. These ponds

can trap many California red-legged frog egg masses and larvae and eliminate reproductive

output.

California red-legged frogs have evolved in California’s Mediterranean climate with wet

winters and springs and dry summers and falls, but most of their introduced predators have not.

In most cases, pond management that mimics the natural water cycle will be most beneficial

for the California red-legged frog.

Red-legged Frog Biology

Ponds that successfully enhance California red-legged frog populations must complement their

biology. The frogs breed from December to April in ponds and streams. They seem to choose

the sites that have the warmest water available, as long as it is at least 20 centimeters (8 inches)

deep. Tadpoles hatch in a few days, depending on temperature, and develop through the spring.

They start to transform into froglets in June or July, and by late August most have completed

the process.

Outside of the breeding season, adult frogs seek out water greater than 1 meter (3 feet) deep for

escape from predators. In some areas, late summer water can be very scarce, and frogs will

travel to congregate in old dug wells, in deep holes in drying streams, or in and around springs.

With the first soaking rains of fall, frogs tend to move away from their summer refuges.

During a rainy winter, they may establish a temporary residence quite a distance from any

body of water. At this time they often gradually move towards the late winter breeding site.

Choosing a Site

At the present time, stock ponds are useful for rehabilitation and enhancement of California

red-legged frog populations only if the frogs can get to them. We must approve the transport

and reestablishment of the California red-legged frog into areas where they do not now occur.

Reestablishment is only considered after intensive studies of both the donor and recipient sites,

with guarantees that the donor population will not be damaged. Given this, ponds for the

benefit of California red-legged frogs should be limited to areas that already contain at least a

remnant population. In such areas, if the ponds are suitable, the frogs will find them on their

own and will not need to be moved.

Ponds should be located as far as possible from predator source-areas. Bullfrogs from a pond

with a large population will quickly invade a new pond up to a few hundred meters (about
152 Recovery Plan for the California Red-legged Frog

1,000 feet) away, but it should take them longer to build up to damaging population levels if

the ponds are separated by a kilometer (0.6 mile) or more. Raccoons are also a serious

California red-legged frog predator in many places. They build up to many times the normal

population density in urban areas and campgrounds with a plentiful supply of garbage, and dog

and cat food.

Pond Design

Suggestions for pond design are based on observations of frogs in many habitats, but they have

not been experimentally tested for efficacy. Further research will surely modify or eliminate

some of these suggestions. The final design depends on a number of considerations such as the

terrain, the use of the pond, and the adequacy and timing of the water supply. From a

biological point of view, pond design is most tightly restricted when bullfrogs are present in

the area.

The ideal pond probably has two main components: a deep-water escape portion and a shallow

tadpole- and juvenile-rearing section. The former should have areas that are deeper than 1

meter (3 feet). It may not matter if this part is clogged with aquatic vegetation. Mats of floating

submerged vegetation in deep water seem to be ideal for the adult frog in the non-breeding

season. Predators such as raccoons and herons, and even large bullfrogs, probably find it

difficult to reach California red-legged frogs on floating mats.

The tadpole-rearing portion should be unshaded and shallow enough to warm quickly in the

winter sun. Submerged aquatic vegetation seems to be tolerated, but emergents such as willows

(Salix), cattails (Typha), or bulrushes (Scirpus) shade the water and keep it cool. The pond

must contain water for tadpole development during the entire rearing season (minimally March

through July in most areas), but it can be allowed to dry at other times of the year.

If the main pond dries regularly, adult frogs will use a restricted summer refuge. In places with

a high water table, these can be dug wells if they have deep, perennial water and protecting

vegetation and are designed so frogs can get out (i.e., not too deep and steep sided). Springs

can also be easily modified as summer refuges.

Discouraging Predators

Perhaps the most important factor in discouraging aquatic vertebrate predators of the

California red-legged frog is the installation of a pond drain. If the pond can be regularly and

completely drained, even once every 3 or 4 years, bullfrog and fish populations will be greatly

reduced or eliminated. Bullfrog eggs are laid in the early summer (April through July), and the

majority of tadpoles do not transform until the following year. If the pond is completely

drained in the fall or winter, bullfrog (and fish) life cycles will be broken.

Bullfrog tadpoles and adults are usually associated with deep water, and extensive shallow,

marshy areas may favor the California red-legged frog. Also, small isolated ponds a few meters

(several yards) across, such as dug out spring heads, may harbor the California red-legged

frog, but may not be attractive to bullfrogs.

Chemical means of bullfrog tadpole and fish control are possible (e.g., use of rotenone), but

their use requires the permission of the California Department of Fish and Game and the U.S.

Fish and Wildlife Service to ensure that the California red-legged frog and other native wildlife

will not be harmed.
Recovery Plan for the California Red-legged Frog 153

The Role of Grazing

Pond management usually needs to be integrated with the local livestock grazing program.

Grazing can be an important tool to help keep the shallower, tadpole-rearing portions of the

pond free of emergent vegetation that shades the water. The shallows should be deep enough

so that livestock do not churn them into a mucky mire, but shallow enough so that the animals

can graze comfortably. Ponds with fluctuating levels where the shallow portions dry each year,

facilitate this type of grazing management.

Many ponds used by cattle gradually become shallow mud holes as cattle trample the banks.

To prevent this, the deepest portion of the pond should be fenced so that cattle cannot enter.

This can be done so that the primary function of the pond, which is to provide livestock water,

is not compromised, but deep escape water is preserved for frogs.

The critical periods for livestock water on many California ranges is late summer and early

fall. Draining of ponds for bullfrog and fish control can usually be postponed until after the

first fall rains, when livestock water is less critical. Alternatively, a temporary catch basin

below the drained pond could provide livestock water. Water in the catch basin could be

maintained until the main pond refills, then the catch basin could be drained. A catch basin

should also be used if there is danger of releasing unwanted predators into a downstream body

of water.
154 Recovery Plan for the California Red-legged Frog

APPENDIX E. PRIVATE LANDOWNER INCENTIVES FOR IMPLEMENTATION

OF CONSERVATION MEASURES

A. NATIONAL RESOURCE CONSERVATION SERVICE PROGRAMS

The 1996 Farm Bill authorized $2.2 billion nationally in funding for conservation programs,

extended the Conservation Reserve Program and Wetland Reserve Program, and created new

initiatives to improve natural resources on America’s private lands. To qualify for market

transition payments under basic commodity programs which replace traditional farm subsidies,

farm operators must agree to abide by Conservation Compliance and Wetlands Conservation

(Swampbuster) provisions in the 1996 Farm Bill. As of October 2001, some of these programs

have ceased to be funded but due to the overwhelming support for Farm Bill programs, future

reauthorization and funding is expected.

1. Conservation Reserve Program

The Conservation Reserve Program encourages farmers to convert highly erodible cropland

or other environmentally sensitive acreage to vegetative cover, such as non-native and

native grasses, wildlife plantings, trees, filter strips, or riparian buffers. Farmers receive an

annual rental payment for the term of the multi-year contract. Cost sharing is provided to

establish the vegetative cover practices. This program allows up to 34.4 million acres,

nationally, to be enrolled at any one time. New enrollments can replace expired or

terminated contracts.

2. Wetland Reserve Program

The Wetland Reserve Program is a voluntary easement program that offers financial

incentives to help landowners restore and protect wetlands. The program targets farmed

wetlands and farmland that once was wetland. A priority is given to areas offering the most

wetland benefits (lands adjacent to restorable wetlands that contribute significantly to

wetland functions and values, previously restored wetlands that need long-term protections,

upland areas needed to provide an adequate ecological buffer or otherwise contribute to

defining a management boundary, existing or restorable riparian habitat corridors that

connect protected wetlands and lands substantially altered by flooding where there is a

likelihood of successful wetland restoration at a reasonable cost). The program offers three

options to protect, restore, and enhance wetlands and associated uplands: permanent

easements, 30-year easements, or 10-year restoration cost share agreements.

3. Wetland Conservation (Swampbuster)

The Wetland Conservation provision allows landowners to comply with wetland

conservation requirements while protecting natural resources under the 1996 Farm Bill. It

provides more options for mitigation by including restoration, enhancement, or creation as

long as wetland functions and values are maintained. The program stipulates that wetland

conservation activities, authorized by permits issued under section 404 of the Clean Water

Act, which make agriculture production possible, will be accepted for Farm Bill purposes if

they were adequately mitigated. It requires wetland determinations to be certified by the

National Resource Conservation Service. It also establishes a pilot program for wetland

mitigation to allow the U.S. Department of Agriculture to assess how well mitigation

banking works for agriculture.
Recovery Plan for the California Red-legged Frog 155

4. Environmental Quality Incentives Program (EQIP)

The Environmental Quality Incentives Program was established in the 1996 Farm Bill to

provide a single, voluntary conservation program for farmers and ranchers to address

significant natural resource needs and objectives. Nationally, this program provides

technical, financial, and educational assistance, half of it targeted to livestock-related

natural resource problems and the other half to more general conservation priorities.

The program works in priority areas where there are serious and critical environmental

needs and concerns. These critical needs areas are determined and prioritized by the

National Resource Conservation Service, other U.S. Department of Agriculture agencies,

and local work groups. High priority is given to areas where State or other local

governments offer financial or technical assistance and where agricultural improvements

will help meet water quality and other environmental objectives. All Environmental

Quality Incentives Program activities must be carried out according to a conservation plan.

The program offers 5 to 10-year contracts that provide incentive payments and cost sharing

for conservation practices needed at the site. Cost sharing may pay up to 75 percent of the

costs of certain practices important to improving and maintaining the health of the natural

resources of the area. Incentive payments can be made to encourage producers to perform

land management practices including wildlife habitat management. Incentive payments can

be up to 100 percent of the producer’s cost.

The program funding comes from commodity credit corporations. The budget is $200

million per year, nationally, through the year 2002. Conservation practices for natural

resource concerns related to livestock production will receive 50 percent of the funding.

Total cost share and incentive payments are limited to $10,000 per person per year and

$50,000 over the length of the contract.

5. Wildlife Habitat Incentives Program

The Wildlife Habitat Incentives Program is a voluntary program for people who want to

develop or improve fish and wildlife habitat primarily on private lands. It provides both

technical assistance and cost share payments to help establish and improve fish and

wildlife habitat. The National Resource Conservation Service helps participants prepare a

wildlife habitat development plan in consultation with the local conservation district. The

plan describes the landowner’s goals for improving wildlife habitat, includes a list of

practices and a schedule for installing them, and details the steps necessary to maintain the

habitat for the life of the agreement. This plan may or may not be part of a larger

conservation plan that addresses other resource needs, such as water quality and erosion.

Cost share assistance includes an agreement for wildlife habitat development and usually

lasts 5 to 10 years.

Under the agreement:

1. The landowner agrees to install and maintain the program practices and allow the

National Resource Conservation Service or its agent access to monitor the effectiveness

of the practices.

2. The U.S. Department of Agriculture agrees to provide technical assistance and pay up

to 75 percent of the costs of installing the wildlife habitat practices.

Wildlife Habitat Incentives Program funds are distributed to States based on state wildlife
156 Recovery Plan for the California Red-legged Frog

habitat priorities which may include: a) wildlife habitat areas; b) targeted species and their

habitats; and c) specific practices.

The program may be implemented in cooperation with other Federal, State, or local

agencies; conservation districts; or private conservation groups. State priorities in

California for the Wildlife Habitat Incentives Program are the following:

1. Riparian area and stream habitat restoration or enhancement.

2. Federal or State threatened or endangered species habitat restoration or enhancement.

3. Treatment or improvement of habitats in uplands (rangeland, woodland, and forest

land).

4. Wetland area creation, restoration, enhancement, and management.

5. “Farmland compatible” habitat development (odd areas, ditches, field borders, rights-ofway, and other areas in or adjacent to farmland fields).

6. Cold water fisheries habitat restoration and enhancement (including salmon, steelhead,

and trout).

7. Restoration or enhancement of critical habitat related to endangered species.

8. Habitat restoration and enhancement for game species and other species.

6. Forestry Incentives Program (FIP)

The Forestry Incentives Program supports good forest management practices on privately

owned, nonindustrial forest lands. This program is intended to assure the Nation’s ability to

meet future demand for saw timber, pulp wood, and quality hardwoods by planting more

trees and placing more forest land under good forest management. The program provides

65 percent of the cost of tree planting, timber stand improvements, and related practices on

nonindustrial private forest land. The Federal cost share limit is $10,000 per person per

year. The Forest Incentives Program’s forest maintenance and reforestation provide

numerous natural resource benefits, including reduced wind and soil erosion and enhanced

water quality and wildlife habitat. The program is administered by the Natural Resource

Conservation Service and the U.S. Forest Service.

7. California Stewardship Incentives Program

The California Stewardship Incentives Program is similar to the Forest Incentives Program.

Whereas the Forest Incentives Program requires that the total private acreage be timbered

acreage potentially suitable for timber production, the Stewardship Incentives Program only

requires that 10 percent of the land have tree canopy or be planted to trees. Cost share rates

and benefits to natural resources are the same as the Forest Incentives Program.

8. Emergency Conservation Program

The Emergency Conservation Program provides emergency funds for sharing with farmers

and ranchers the cost of restoring to productive use farmland seriously damaged by natural

disasters. This program is available only to solve new conservation problems caused by

natural disasters that impair and endanger the land or materially affect the productive
Recovery Plan for the California Red-legged Frog 157

capacity of the land. The damage must be unusual (except for wind erosion) and not likely

to recur frequently in the same area. Conservation problems existing prior to the disaster

are not eligible for program assistance. Emergency practices to rehabilitate damaged

farmland may include: 1) rehabilitating stream banks, channels, levees, and dikes affected

by the natural disaster; 2) removing debris deposited by a natural disaster (e.g. flood debris)

that interfere with normal farming operations; and 3) restoring land between any levee and

the stream.

9. Emergency Watershed Protection Program

The Emergency Watershed Protection Program, administered by the Natural Resource

Conservation Service, provides technical and financial assistance to communities for

restoring watersheds ravaged by natural disasters such as, floods, fires, wind storms,

earthquakes, and drought. Through the Emergency Watershed Protection Program, the

Natural Resource Conservation Service provides assistance to prevent damage from

flooding, runoff, and erosion, reducing the threat to life and property. The Natural Resource

Conservation Service helps repair over-topped levees, dikes, and other flood retarding

structures. Assistance is also available to help clear water courses clogged by sediment and

debris to prevent future flooding. Other available measures include establishing vegetative

cover, controlling gullies, and protecting stream banks.

This assistance protects homes, businesses, and other properties from further damage in the

event of subsequent storms. The Natural Resource Conservation Service also provides

financial assistance covering up to 75 percent of construction costs of eligible emergency

treatments. Local sponsors of program projects are responsible for obtaining the necessary

permits, providing 25 percent cost share, and providing for the operation and maintenance

of completed emergency measures.

10.Resource Conservation and Development Program

The Resource Conservation and Development Program was initiated in 1962 to help people

care for and protect their natural resources and to improve an area’s economy, environment,

and living standards. The program provides a way for local residents to work together and

plan how they can actively solve environmental, economic, and social problems facing

their communities. Assistance is available from the Natural Resource Conservation Service

for planning and installation of approved projects specified in Resource Conservation and

Development area plans, for land conservation, water management, community

development, and environmental enhancement. The program provides for multi-county

planning coordination. Groups of landowners, communities, nonprofit organizations, and

local government agencies are eligible to participate in this program, as well as Native

American landowners and Tribal trust lands meeting the requirement that land is located in

a Resources Conservation and Development area.

Land must be in a United States Department of Agriculture-recognized Resource

Conservation and Development area. Currently these areas are: OreCal Resource

Conservation and Development area in Siskiyou and western Modoc Counties in

California, and Klamath/Lake Counties in Oregon; North Cal Neva Resource Conservation

and Development area in Lassen, Plumas, and western Modoc Counties in California and

Washoe County, Nevada; Trinity County Resource Conservation and Development area in

Trinity County, California; High Sierra Resource Conservation and Development area in

Nevada, Placer, El Dorado, Sierra, and Amador Counties in California; Central Coast

Resource Conservation and Development area in Santa Cruz, Monterey, San Benito, and

San Luis Obispo Counties in California.
158 Recovery Plan for the California Red-legged Frog

Assistance is provided in the form of: 1) technical assistance and 2) grants (as funding

allows) up to 25 percent of the total cost, not to exceed $50,000. Local or State

governments must provide 10 percent of the total cost and they are responsible for the

operation and maintenance.

11. Other Programs

Several other programs administered by the Natural Resource Conservation Service are

designed to protect natural resources on a watershed basis. These include River Basin

Studies and Water Project Plans. River Basin Studies identify water and land resource

problems, and analyze the economic base and environmental setting. Alternative plans for

solving problems and improving the economy and the environment are offered. Watershed

Project Plans and Environmental Impact Statements provide plans that assist urban and

rural communities to protect, improve, and develop water and land resources in watersheds

up to 92,000 hectares (250,000 acres). The Natural Resource Conservation Service may

provide both technical and financial assistance in the planning and implementation of

watershed projects. The local sponsors may have major obligations in these projects,

including obtaining 25 percent of the funding to implement the projects and the

responsibility for insuring the operation and maintenance of the installed practices which

make up the project. Wetland restoration, creation, or enhancement is often used to mitigate

wildlife habitat losses caused by project actions.

B. U.S. FISH AND WILDLIFE SERVICE PROGRAMS

1. Partners for Fish and Wildlife

Partners for Fish and Wildlife is our habitat restoration cost-sharing program for private

landowners. The program was established to offer technical and financial assistance to

landowners who wish to restore wildlife habitat on their property. On-the-ground habitat

improvement projects that benefit Federal trust species include restoration of wildlife

habitat on degraded or converted wetlands, riparian areas, native grasslands, and streams.

The assistance we provide can range from giving informal advice on the design and

location of a potential restoration project, to designing a project and funding up to 50

percent of the implementation costs under a formal cooperative agreement with the

landowner. Projects with the highest priorities are those that reestablish the natural

historical communities and provide benefits to migratory birds, anadromous fish, and

threatened and endangered species. Projects include efforts such as, but not limited to:

creating shallow water areas, revegetating native plants, erecting fences along riparian areas

to exclude livestock, grazing plans to benefit livestock and wildlife, pesticide use reduction,

water level management, and soil and water quality improvements.

The process is as follows:

We meet with the landowner and any representative from other cooperating agencies or

organizations on the property to discuss the landowner’s goals and objectives. We provide

technical advice on project design, material, and engineering as appropriate. Cost sharing is

proposed. A habitat restoration proposal, developed by the landowner and our staff, is

submitted to one of our State offices to compete for funds. After funding is approved, the

Wildlife Extension Agreement is signed. Upon project completion, we will reimburse the

landowner after receipts and other documents are submitted according to the agreement.
Recovery Plan for the California Red-legged Frog 159

2. Safe Harbor Programs

Many public and private interests have suggested that there be an incentive for private

landowners and/or public land managers to voluntarily enhance habitat for California redlegged frogs or to participate in reestablishment efforts for this species in historically

occupied areas. Many have concerns that doing so, without proper incentive programs in

place, will pose a long-term regulatory threat. This is particularly a concern for those

landowners who may be situated adjacent to areas undergoing reestablishment. For this

reason, a safe harbor program may be the best vehicle to encourage voluntary

reestablishment programs and alleviate the concerns of neighboring landowners. A Safe

Harbor Agreement is a voluntary agreement between us and one or more private or nonFederal landowners to restore, enhance, or maintain habitats for listed species, candidates,

or other species of concern. Under the Agreement, we provide the landowner with

assurances that additional land use actions would not be imposed. If the Agreement

provides a net conservation benefit to the covered species and the landowner meets all the

terms of the Agreement, we would authorize the incidental taking of covered species to

enable the landowner to return the enrolled lands to agreed upon conditions.

The California red-legged frog appears to be a good candidate for application of a safe

harbor program. Because recovery planning emphasizes the importance of maintaining

viable metapopulations and protecting a network of connected habitats, it is reasonable to

assume that any conservation measure that is enacted (albeit with the understanding that it

is implemented under a potentially limited time frame via a safe harbor agreement) will

provide potential short term benefits to an individual population but lasting benefits to the

overall metapopulation. For example, if habitat is created via enhancements of a stockpond

such that the stockpond is colonized by California red-legged frogs or if a stockpond is

stocked with translocated individuals, this restoration action will presumably provide some

number of years of suitable habitat for successful breeding. This will in turn, provide

dispersers into adjacent habitats. If a landowner decides to remove this habitat at some

future point in time, the overall metapopulation will still have gained by the potential

increase in subpopulations. Provided that adjacent landowners are party to the agreement,

all colonized habitats could be covered under the agreement, perhaps with staggered time

periods/endpoints. Opportunities for enhancement of habitat exist rangewide and the use of

safe harbor programs may substantially facilitate implementation of recovery actions.

There are several steps to develop a Safe Harbor Agreement and obtain the appropriate

permits. An interested landowner should contact the nearest Fish and Wildlife Service Field

Office and speak to someone about the program. The landowner, with our the aid, must

provide some background information including the location and of the property, the

proposed management actions, and the species that will benefit. We (or appropriate

cooperators as approved by the landowner) will describe the baseline conditions for the

enrolled property in terms appropriate for the listed species. Baseline conditions include the

number and location of individuals, if it can be determined, and also includes an assessment

of habitat extent and quality. Both parties will discuss land use objectives, assess habitat

quality, and identify any other information needed to develop an Agreement. After this, a

Safe Harbor Agreement is developed; it should include a monitoring program to assess the

success of the management practices. Assurances are provided through a “enhancement of

survival” permit once the Agreement is developed. We complete an internal section 7

review and a public comment period, issue a 10(a)(1)(A) permit, and finalize the

agreement. This permit allows the landowner to return the property to the baseline

conditions at the end of the Agreement. Safe Harbor Agreements will be honored after the

sale of the enrolled property if the new owner willingly signs the original Agreement;

agreements can also be renewed.
160 Recovery Plan for the California Red-legged Frog

C. STATE OF CALIFORNIA PROGRAMS

1. California Resource Conservation Districts

Conservation Districts emerged during the 1930s as a way to prevent the soil erosion

problems of the Dust Bowl from recurring. Formed as independent local liaisons between

the Federal government and landowners, conservation districts have always worked closely

with the USDA Natural Resources Conservation Service. Resource Conservation Districts

address a wide variety of conservation issues such as forest fuel management, water and air

quality, wildlife habitat restoration, soil erosion control, conservation education, and much

more.

Resource Conservation Districts render assistance to private landowners wishing to

conserve soil and water and manage their resources on a sustainable basis. But Resource

Conservation Districts also act as a focal point for local conservation efforts, and Resource

Conservation Districts throughout the State now function as leaders in the conservation

community, including a large number of watershed groups such as Coordinated Resource

Management Planning (CRMP) groups throughout the State. Resource Conservation

Districts continue to sponsor educational efforts to teach children and adults alike of the

importance of conserving resources.

California now has 103 Resource Conservation Districts, most of which are funded largely

through grants. A few receive limited funds through county property tax revenues. The

Department of Conservation and the Natural Resources Conservation Service provide

training and in-kind support, as well as a watershed grant program for districts.

2. California Forestry Incentives Program (CFIP)

The purpose of the California Forest Improvement Program is to encourage private and

public investment in, and improved management of, California forest lands and resources.

This focus is to ensure adequate high quality timber supplies, related employment and other

economic benefits, and the protection, maintenance, and enhancement of a productive and

stable forest resource system for the benefit of present and future generations.

The program scope includes the improvement of all forest resources, including fish and

wildlife habitat, soil, and water quality. The program provides technical assistance to private

forest landowners, forest operators, wood processors, and public agencies. Cost share

assistance is provided to private forest landowners, Resource Conservation Districts, and

non-profit watershed groups. Cost-shared activities include management planning, site

preparation, tree purchase and planting, timber stand improvement, fish and wildlife habitat

improvement, and land conservation practices for ownerships containing up to 5,000 acres

of forest land.

D. GREEN CERTIFICATION PROGRAMS

Green Certification programs have recently been developed to bring environmental

concerns to the marketplace. Products that are generated using environmentally sensitive

methods are offered as alternatives to traditionally produced items. There is a double

incentive for these types of programs that leads to reduced environmental effects. Producers

are encouraged by the potential for higher income, and consumers are stimulated by the

prospect of owning higher-valued specialty items. Both are motivated by personal desires to

contribute to good land stewardship and sustainable environments. These programs

typically involve certification of the producer by an independent party using criteria
Recovery Plan for the California Red-legged Frog 161

generated through ecological and economic research. Certification can be done to verify

lowered impacts to a species or group of species (e.g., Dolphin-Safe Tuna) or to verify that

land management practices in general meet sustainability criteria (e.g., the Smart Wood

Program).

There are a number of programs that could be considered as models for setting up criteria

and a labeling program for the California red-legged frog. “Dolphin-Safe Tuna” labeling

was one of the first such programs. This program uses independent monitors that have

unrestricted access to fishing boats and manufacturing facilities to document the minimal

effects of tuna fishing on dolphins. There are numerous large companies that now use the

Dolphin-Safe label. Another species-specific program is “Bird-Friendly Coffee.” Recent

changes in the way coffee is grown (from under forest canopies that provide shade to openfield, sun grown) have had significant negative impacts to native birds in the tropics and

neotropical migrants. This program uses criteria developed by the Smithsonian Migratory

Bird Center, as applied by independent evaluators, to certify coffee as shade-grown and

“Bird Friendly.” There is at least one coffee company now that produces and sells this

certified coffee.

Several other programs provide certification to landowners that use ecologically sustainable

land management practices. Two examples of these types of programs are “Smart Wood”

and “Salmon Safe.” Both are overseen by independent non-profit entities that have

developed specific criteria for their local area. In the case of “Salmon Safe,” small

agricultural landowners in California and Oregon are currently the main focus. Expert

evaluators use criteria and scoring guidelines developed by the Pacific Rivers Council

(Eugene, Oregon) to certify that farmland management uses with best management

practices to avoid harm to stream ecosystems. These practices may result in restoration of

currently degraded areas. The following four criteria guide this process: 1) quality of

management of riparian and wetland areas; 2) quality of management of water use and

irrigation; 3) approaches to uses of pesticides, herbicides, and fertilizers; and 4) erosion and

sediment control measures. More specific sub-criteria are used to do actual scoring. The

“Smart Wood” program, developed by the Rainforest Alliance (New York City, New York)

is probably the largest wood products certification program. The program certifies wood

products, resource managers, and manufacturing companies that produce and handle wood

that has been generated using ecologically sustainable practices. Local organizations

typically develop region-specific criteria that are then approved by the “Smart Wood”

program. An example are the certification criteria used by the Institute for Sustainable

Forestry in Redway, California. Their approach includes evaluation of: 1) the overall forest

and watershed management plan, 2) silvicultural techniques, 3) the monitoring plan, 4) road

management and sediment production, 5) stream and riparian management, 6) wildlife and

biodiversity management, 7) fire and fuels management, 8) wildlife habitat, 9) roads and

trails, 10) yarding, 11) special resources, 12) restoration, 13) community and economic

stewardship, 14) use of local workforce, and 15) documentation of the “chain of custody”

(how the wood is tracked through to a final product).

Developing a program to encourage private landowners and businesses to practice land

management activities that are sensitive to the needs of the California red-legged frog could

be based on a combination of the approaches used by the “Salmon Safe” and “Smart Wood”

programs. These two programs cover the main impacts to the California red-legged frog in

many areas of its current range. Agriculture, livestock grazing, and forestry practices could

be certified as “frog friendly” by independent evaluators based on criteria developed by the

recovery plan technical team or another science-based group. These criteria might include:

1) management of ponds, wetlands, and streams; 2) management of adjacent upland areas;

3) lack of exotic vertebrate species and/or a program for reduction of exotic species on the

property; and/or 4) minimal use of chemical pesticides, herbicides, and fertilizers.
162 Recovery Plan for the California Red-legged Frog

APPENDIX F. CODE OF PRACTICE TO REDUCE SPREAD OF DISEASE AND PARASITES

A Code of Practice was prepared by a group of scientists within the Declining Amphibian

Populations Task Force to provide guidelines for use by anyone conducting fieldwork at

amphibian breeding sites or in other aquatic habitats. While this protocol has not been

reviewed and endorsed by the task force at large, the Code of Practice serves as a starting point

for the development and adoption of measures that reduce the spread of disease and parasites

(see task 7 in the Stepdown Narrative Outline).

Observations of diseased and parasite-infected amphibians are now being frequently reported

from sites all over the world. This has given rise to concerns that releasing amphibians

following a period of captivity, during which time they can pick up infections of novel disease

agents, may cause an increased risk of mortality in wild populations. Amphibian pathogens and

parasites can also be carried in a variety of ways between habitats on the hands, footwear, or

equipment of fieldworkers, which can spread them to novel localities containing species which

have had little or no prior contact with such pathogens or parasites. Such occurrences may be

implicated in some instances where amphibian populations have declined. Therefore, it is

extremely important for those involved in amphibian research and other types of wetland/pond

studies (such as those on fish, invertebrates, and plants) to take steps to minimize the spread of

disease agents and parasites between study sites.

The Declining Amphibian Populations Task Force Fieldwork Code of Practice:

1. Remove mud, snails, algae, and other debris from nets, traps, boots, vehicle tires, and all

other surfaces. Rinse cleaned items with sterilized (eg., boiled or treated) water before

leaving each study site.

2. Boots, nets, traps, etc. should then be scrubbed with 70 percent ethanol solution and rinsed

clean with sterilized water between study sites. Avoid cleaning equipment in the immediate

vicinity of a pond or wetland.

3. In remote locations, clean all equipment with 70 percent ethanol or a bleach solution, and

rinse with sterile water upon return to the lab or a “base camp.” Elsewhere, when washingmachine facilities are available, remove nets from poles and wash (in a protective mesh

laundry bag) with bleach on a “delicates” cycle.

4. When working at sites with known or suspected disease problems, or when sampling

populations of rare or isolated species, wear disposable gloves and change them between

handling each animal. Dedicate sets of nets, boots, traps, and other equipment to each site

being visited. Clean and store them separately at the end of each field day.

5. When amphibians are collected, ensure the separation of animals from different sites and

take great care to avoid indirect contact between them (e.g., via handling, reuse of

containers) or with other captive animals. Isolation from unsterilized plants or soils which

have been taken from other sites is also essential. Always use disinfected and disposable

husbandry equipment.

6. Examine collected amphibians for the presence of diseases and parasites soon after capture.

Prior to their release or the release of any progeny, amphibians should be quarantined for a

period and thoroughly screened for the presence of any potential disease agents.

7. Used cleaning materials (liquids etc.) should be disposed of safely and, if necessary, taken

back to the lab for proper disposal. Used disposable gloves should be retained for safe

disposal in sealed bags.
Recovery Plan for the California Red-legged Frog 163

APPENDIX G. GENERAL GUIDELINES FOR REESTABLISHMENT

OF CALIFORNIA RED-LEGGED FROG POPULATIONS

General Guidelines

The successful reestablishment of frog populations as a conservation measure is largely

unproven. However, reestablishment could be an important tool for repopulating large areas,

especially in southern California, the foothills of the Sierra Nevada, and North Coast Range

foothills that have lost their California red-legged frog populations. Reestablishment can also

be used for the occupation of newly created habitats that cannot be easily reached from

existing populations. Programs of reestablishment should not be entered upon lightly as they

are expensive, and a long-term commitment of time and funds is imperative.

Attempts to reestablish the California red-legged frog should be made only if the following list

of criteria are met. Detailed explanations of these criteria follow the list:

1) The California red-legged frog formerly occupied the general area;

2) The habitat appears to be suitable, is under long-term protection, and predators (especially

exotic fishes and frogs) can be eliminated or kept to manageable levels;

3) The reasons for the species’ absence have been determined and eliminated or minimized;

4) No reproducing populations of the California red-legged frog remain in the area, and it is

not likely to be reinvaded from surrounding populations in the near future;

5) The effort can commit to:

a) Releases of propagules at each site through at least 5 consecutive years, preferably at

several sites within the area; and

b) Monitoring for at least 10 years after the last release.

Explanations:

1) The historic range of the California red-legged frog encompassed the Central Valley of

California, the Coast and Transverse ranges south of Mendocino County, southern

California west of the deserts, and northern Baja California west of the Sierra San Pedro

Mártir (see page 6 of the Introduction). Reestablishment can be considered in areas,

including those with newly created habitats, that are currently unoccupied by the

California red-legged frog, as long as the other criteria are fulfilled. Augmentation of any

California red-legged frog populations is not recommended.

2) Habitat quality is defined in Section I. A favorable mix of breeding, rearing, and summer

habitats relatively free of predators is the key element of habitat quality. At least three

potential breeding/rearing sites should be identified within each habitat block. Single

ponds, unsupported by a network of other ponds or streams, should not be considered for

reestablishment programs.

Sites must be protected from threats and incompatible uses in the foreseeable future.

Biologists must be assured of access to the entire metapopulation habitat block for

monitoring purposes. Top priorities for reestablishment should be those sites that have

high quality habitat and that are most remote in distance from existing populations.

3) The reasons for the original disappearance or absence of the California red-legged frog

must be identified and corrected.

4) Usually reestablishment will not be considered if there are populations present in the

same recovery unit, unless the sites are isolated by habitats that are not easily crossed by
164 Recovery Plan for the California Red-legged Frog

the California red-legged frog. Exceptions may also be made for newly created habitats

that do not have an existing population nearby. Propagules should ideally be taken from

the populations that are geographically closest to the reestablishment sites.

5) Reestablishment can be expensive, and unless the parties involved are dedicated to

spending the necessary funds over a suitable time period, it is better not to embark on a

program. This commitment must include the monitoring phase.

a) Releases of about 1,000 eggs should be made at each breeding site within the habitat

block for each of 5 years. If these goals cannot be achieved, the project should not be

considered. In an emergency (extreme drought, flooding), a year might be skipped. In

that case, the intended releases should be made in the sixth year instead. If more than

1,000 eggs are available, other sites should be considered for reestablishment. Each

site should receive at least 500, but not more than 1,000, eggs each year.

b) The cheapest and most efficient way to secure propagules for reestablishment is to

collect as many whole or partial egg masses as necessary to provide 1,000 eggs for

each reestablishment site. In different years, rotate the take of eggs among several

subpopulations if at all possible.

c) Monitoring reestablished populations is critical. If the fate of the population is not

known, the effort is wasted. Much can be learned by monitoring even a failed

reestablishment effort. Detailed monitoring is especially important during the first

reestablishment program; the lessons learned will be used to guide all future efforts.

Implementation

Reestablishment as a recovery strategy should be considered in the following areas: Recovery

Unit #1, the Sierra Nevada; Recovery Unit #2, the Coast Range foothills and western

Sacramento River Valley; and Recovery Unit #8, the Southern Transverse and Peninsular

ranges.

The steps to be taken are:

1. Survey the areas and determine their suitability, based on the above criteria. Choose suitable

breeding/rearing sites.

2. Locate source metapopulations. Determine that enough adult females are present in each

population to provide the necessary egg masses. As a rule of thumb, no more than 10

percent of the egg masses should be taken from a given site.

3. Collect either freshly laid eggs or those that are hatching. The intermediate stages are

delicate and should not be disturbed. Keep the water cool and move the intact egg mass as

quickly as possible to the release site. Divide the egg mass as necessary when you get to

the release sites.

4. Monitoring should consist of annual survey sessions wherein all California red-legged frogs

captured are sexed, weighed, measured, and examined for passive integrated transponder

(PIT) tags. Tags should be inserted in those that lack them. The data should be

immediately analyzed to examine the survival of each cohort. At the same time, the entire

habitat block should be examined to document the rate of spread from the original release

sites.
Recovery Plan for the California Red-legged Frog 165

Summary of Section 10(j) of the Endangered Species Act of 1973: Experimental

Populations

Reintroduction of the California red-legged frog is consistent with the goals of the Endangered

Species Act. Guidelines for such activities are provided under section 10(j). This section

allows the release (and the related transportation) of any population (including eggs,

propagules, or individuals) of an endangered species or a threatened species outside the current

range of such species if the Secretary of the Department of Interior determines that such

release will further the conservation of a species.

Before authorizing the release of any population, the reintroduced population should be

identified, on the basis of the best available information, as an essential population (i.e, the

population is essential to the continued existence of an endangered species or a threatened

species) or as a nonessential population. This section also provides the Secretaries of the

Departments of Interior and Commerce with the power to designate certain populations of

listed species as experimental populations. The term experimental population means any

population (including any offspring arising solely therefrom) authorized for release that are

wholly separate geographically from nonexperimental populations of the same species.

Each member of an experimental population shall be treated as a threatened species unless the

experimental population is considered to be nonessential to the continued existence of a

species. If it is nonessential, it is treated as a species proposed to be listed under section 4 of

the Act. If the nonessential population occurs in an area within the National Wildlife Refuge

System or the National Park System however, it is treated as threatened with either

designation.

The best known cases in which the status “experimental/nonessential” has been used are the

reintroductions of the endangered red wolf in North Carolina and the threatened gray wolf in

Idaho and in Yellowstone National Park. Ordinarily, private landowners cannot chase an

endangered species such as the red wolf off of their land or away from their livestock because

section 9 of the Endangered Species Act prohibits “harassing” of listed animals. However, in

both the red and gray wolf cases, the animals that were released were designated experimental/

nonessential, allowing landowners to kill individual wolves caught preying upon livestock.

This designation helped reduce public opposition to wolf reintroductions by giving landowners

some control over problem animals. While this designation reduces Endangered Species Act

protections, it can be an invaluable tool in gaining public support. This strategy can facilitate

species recovery in appropriate circumstances.

Reestablished populations of the California red-legged frog may not be critical to the

continued existence of the species and therefore will be considered as nonessential

populations. Because recovery goals hinge on connectivity of habitat and maintenance of

metapopulations of California red-legged frogs, whereby there is dispersal of individuals

between populations and colonization and/or recolonization of habitats, most reestablished

populations are not likely to be geographically isolated from existing populations and thus will

not qualify as an experimental population. In some core areas, reestablished populations will

be geographically isolated initially; in these cases, the experimental approach may be judged

appropriate and should be considered on a site by site basis. Formal designation of

nonessential/experimental status will be required.
166 Recovery Plan for the California Red-legged Frog

APPENDIX H: SUMMARY OF AGENCY AND PUBLIC COMMENTS ON THE DRAFT RECOVERY

PLAN FOR THE CALIFORNIA RED-LEGGED FROG

In May, 2000, we released the Draft Recovery Plan for the California Red-legged Frog (Draft

Plan) for a 90-day comment period. This comment period was extended for an additional 90

days and the entire public comment period ended on November 7, 2000. During this open

comment period, comments for Federal agencies, State and local governments, and members

of the public were collected. Marc Hayes, John Bolger, Samuel Sweet, and Jerry Smith were

asked to provide peer review of the draft plan. Comments were received from one peer

reviewer.

This section provides a summary of general demographic information including the total

number of letters received from various affiliations and States. It also provides a summary of

the major comments. All letters of comment on the draft plan are kept on file in the

Sacramento Fish and Wildlife Office at 2800 Cottage Way, Room 2605, Sacramento,

California 95825-1846.

The following is a breakdown of the number of letters received from various affiliations:

Federal agencies—11

State agencies—3

local governments—25

environmental/conservation organizations—21

academia/professional—8

business/industry—18

individual citizens—159

This section summarizes the content of significant comments on the draft plan. A total of 245

letters were received, each containing varying numbers of comments. Many specific comments

re-occurred in letters. Most letters provided new information or suggestions for clarity. In these

cases, the information was incorporated into the final version of the recovery plan directly.

Some letters requested an explanation of various points made in the draft plan or their

scientific basis. In these cases, the final recovery plan was revised to include an expansion or

clarification of the particular section. Most comments resulted in revisions to the draft

recovery plan. Many commenters simply provided their voice of support or opposition to the

recovery plan. Information and comments not incorporated into the final version of the

recovery plan were considered, noted, and are on file with the entire package of agency and

public comments; these may become useful in the future. Major comments that were not

incorporated or that require clarification in addition to their incorporation are addressed below.

Summary of Comments and Our Responses

Introduction

Comment: One commenter suggested that the information used in the life history sections of

the introduction is mostly outdated and speculative.

Response: The best available information was used to write the life history sections in the

introduction. Most researchers agree that more information is needed to better understand the

ecology of the California red-legged frog. Nevertheless, published research was used for most

sections. Specific references mentioned in comments were re-evaluated and some sections

were updated using new information. In some cases, anecdotal information provided by field

biologists and/or land managers was used in the recovery plan. Many of these references refer
Recovery Plan for the California Red-legged Frog 167

to distribution and status information that has been collected in the field as part of ongoing

survey and monitoring efforts. While this information is not peer reviewed and published, we

feel that it provides valuable information related to the California red-legged frog. Where nonpublished information was used, we cited the biologists via personal communications or “in

litt” references. These are listed in the bibliography and are in the administrative record which

is available for review in the Sacramento Fish and Wildlife Office.

Comment: The scientific literature used in the discussion of mosquitofish and their predation

on California red-legged frogs appears to be biased.

Response: This recovery plan acknowledges that more information is needed regarding the

complex relationship between mosquitofish and California red-legged frogs; the plan

recommends such research in the list of recovery actions. The recovery plan states that there

are indeed several sites where mosquitofish and California red-legged frogs coexist.

Nevertheless, the literature that is available at this time overwhelmingly suggests that there are

some negative impacts on California red-legged frogs.

Comment: Address catastrophic fire and reduction of fuel buildup.

Response: We are aware of the need to control fuel buildup and thus preclude catastrophic

fires. Recovery team members representing the U.S. Forest Service provided guidelines for

activities related to fire control. These guidelines are included in the recovery plan in the

Guidance for Development of Watershed Management Plans

and Implementation of Recovery Tasks.

Comment: Several commenters suggested that the recovery plan address the threat of

expansion of the University of California Santa Cruz Campus and how it may destroy frog

habitat on Moore and Jordan Gulch drainages.

Response: There are many development projects impacting California red-legged frogs

throughout its range. The recovery plan attempts to capture the nature and effects of threats to

this species in a general manner, using some specific examples where appropriate. Urban

development and expansion is indeed a threat that is contributing to the decline of the

California red-legged frog. The effects of urban development is discussed in the Threats and

Reasons for Decline section, in the Introduction.

The California red-legged frog habitat in Moore and Jordan Gulch drainages are included in

Core Area # 19 which is called Salinas River-Pajaro River and includes the these drainages. As

a result of this comment, the need for alternatives to, or mitigation for, the expansion of UC

Santa Cruz has been added to the specific management and protection recommendations for

this core area (Table 6). It is the goal of the recovery plan that watershed management plans

will be developed for watersheds that harbor California red-legged frogs. As these plans are

developed site specific impacts, such as the expansion of Santa Cruz campus, can be addressed

and remedied.

Any such development proposal would be required to undergo extensive public review and

authorization, including our review of likely effects on threatened and endangered species and

wetlands.

Comment: Address the off-road vehicle interface issues in Calaveras County as a threat to the

California red-legged frog.

Response: As mentioned above, the threats to California red-legged frogs are described in a
168 Recovery Plan for the California Red-legged Frog

general manner in the recovery plan. Off-road vehicle use of frog habitat is a serious concern

and land management recommendations related to this threat are included in the recovery plan.

Regarding this specific area, the off-road vehicle interface area is included in the recovery plan

as a portion of a core area in Calaveras County. This land use is inconsistent with the goals of

core areas, which are to restore and protect habitat and management for California red-legged

frogs. Therefore, minimization of these impacts should be included in the site-specific

watershed management plan.

Comment: A substantial number of non-indigenous animals are being purchased in live-food

markets and then released into local waters and thereby is a means of introducing non-natives

into the ecosystem. Suggest a ban on their importation.

Response: While non-native predators that have been introduced to the ecosystem are clearly

a major reason for the decline of the California red-legged frog, the source of the majority of

non-native species is not live-food markets. In fact, given the practice of stocking lakes for

sport-fishing, using mosquitofish for mosquito abatement, and the degradation of habitat that

has allowed the rampant proliferation of non-native species that have nearly naturalized in

California, this source is relatively insignificant.

Recovery

Comment: Discuss the relationship between core areas for recovery and critical habitat.

Response: A section discussing this relationship has been added to the recovery plan in

Section II. Core areas and critical habitat areas were selected based on similar criteria. The

main criteria used for both were to capture areas: 1) that are occupied by California red-legged

frogs, 2) where populations of California red-legged frogs appear to be source populations,

3) that provide connectivity between source populations, and 4) that represent areas of

ecological significance. For the selection of core areas, areas of ecological significance

include: watersheds that represent the limits of the current and historic range and/or that appear

to be restorable and thus good sites for reestablishment projects. Unlike the selection of core

areas, it is a requirement that primary constituent elements be defined for critical habitat. These

primary constituent elements are described in the recovery plan and are present in all critical

habitat areas and core areas.

The core areas and critical habitat areas differ in several ways. Unlike core areas which have

no legal mandate for protection under the Endangered Species Act and solely rely upon

voluntary implementation, the designation of critical habitat requires Federal agencies to

consult with us regarding any action that could destroy or adversely modify critical habitat.

Adverse modification of critical habitat is defined as any direct or indirect alteration that

appreciably diminishes the value of the habitat for both the survival and recovery of the

species.

Comment: Provide a better justification for identification of core areas that are currently not

occupied.

Response: Restoration of populations in core areas within the historic range, where California

red-legged frogs are currently not present, will prevent range collapse. If the goals of the

recovery plan do not include the historic range, but rather focus on currently occupied areas,

the result will be a vastly smaller range for this species; this limitation would preclude

recovery of the California red-legged frog.
Recovery Plan for the California Red-legged Frog 169

Comment: Remove from core area maps all urbanized areas.

Response: The Sacramento Fish and Wildlife Office has maps on file that were developed

during the recovery planning process that exclude urban areas. The size of maps used in the

recovery plan however, did not allow such a level of detail without compromising the visibility

of core areas and geographic markers. The recovery plan discloses the fact that many areas

within core areas are expected to remain unsuitable due to land uses such as agriculture and

urban development, and are unlikely to be areas where recovery efforts will be implemented. If

readers wish to view the urban areas within core areas, they may do so at the Sacramento Fish

and Wildlife Office.

Comment: Be more specific, in terms of numbers, in defining the recovery criteria.

Response: Discussion of recovery criteria is given in Section II. Recovery strategies and other

recommendations are based upon the best scientific information available. Current

conservation biology and/or life history data were used to develop the standards. Most

recommendations are preliminary because: 1) available data on the covered species are limited

and 2) conservation biology has yet to resolve the details of how endangered species recovery

is best achieved for any species. Recovery strategies and other recommendations may need to

be altered as more data become available and as conservation science develops. We will review

such information periodically.

In the meantime, the recovery plan uses an approach that focuses on ecological integrity,

habitat availability, and metapopulation viability, rather than specific numbers of habitat acres,

individuals, or populations. When the five recovery criteria are met, the result will be a series

of populations that are linked by suitable, connected habitat.

Comment: Recovery goals are unrealistic and introduction of frogs is not necessary in all core

areas.

Response: We agree that introduction of California red-legged frogs in all core areas that

currently do not harbor the species may be challenging. However, given that most core areas

are already occupied, reestablishment efforts are only recommended in several core areas. This

effort may be achieved given adequate time and funding.

When comparing the historic range and number of populations, the core areas represent a

comparatively low number of watersheds. Distribution of California red-legged frogs in all

core areas, with adequate habitat protection in priority 2 watersheds, are necessary to spread

the risk of extinction across the landscape rather than concentrating genetic diversity and

habitat suitability where frogs currently exist or in a smaller number of watersheds.

Maintaining (and establishing where necessary) frog populations in all core areas may

optimize the chances for genetic diversity, habitat connectivity, and ultimately may allow the

species to occupy its former range. These goals cannot be met unless there is an attempt to

recover the frog in each core area.

Comment: Identify public support for recovery and potential resources for implementation.

Response: In Section I, Federal, State, local and private actions are listed that have

contributed to conservation of the California red-legged frog. This section has been expanded

to include more efforts by non-government organizations which are staffed by concerned,

private citizens. Appendix E. lists potential funding sources for implementation; many of these

programs provide financial assistance to willing participants.
170 Recovery Plan for the California Red-legged Frog

Comment: Include recovery goals for the southern Sierra Nevada range, the Central Valley,

and the National Wildlife Refuges.

Response: Aside from the core areas and priority 2 watershed, all other areas within the range

of the species are listed as priority 3 watersheds. Here, the goals are to restore habitat, where

feasible, and allow for recolonization. The recovery plan specifically identifies the southern

Sierra Nevada, Central Valley, and wetlands on National Wildlife Refuges as priority 3

watersheds.

Comment: Eliminate the recommendation for commercial take of bullfrogs as it may pose an

incidental threat to the California red-legged frogs.

Response: Initially, the recovery team agreed that this would be a great contribution to

bullfrog eradication efforts. Several commenters, however, have suggested that the confusion

between California red-legged frog and bullfrog appearances may lead to take of the California

red-legged frog. This task has been removed as a result of these public comments.

Comment: Use consistent methods to define recovery units.

Response: Overall, the method used to delineate revised recovery units was by watershed

boundaries using U.S. Geological Survey hydrologic units. Along the Sierra Nevada mountain

range, the 1,500-meter (5,000-foot) elevation line was used because it is the general range limit

of the California red-legged frog. This method has not changed in the final recovery plan.

Comment: Include East Las Virgenes Creek as a core area for recovery and address the threat

of development at this site.

Response: This area is included in the Santa Monica Bay - Ventura Coastal Streams core area

(core area #50, Figures 39-40 in draft plan; core area #27, Figure 29 in final plan).

Comment: The recovery plan should include a socio-economic impact analysis, particularly in

regards to the potential economic impacts to agriculture.

Response: Because implementation of recovery plans is voluntary and not a legal mandate,

there is no requirement for an economic impact analysis.

Comment: Eliminate certain core areas (e.g. Traverse Creek, Tejon/El Paso).

Response: While developing the final recovery plan, all core areas were re-evaluated to

determine whether they fit the selection criteria. The selection criteria used were to include

areas that: 1) are occupied by California red-legged frogs, 2) where populations of California

red-legged frogs appear to be source populations, 3) that provide connectivity between source

populations, and 4) that represent areas of ecological significance. Areas of ecological

significance include watersheds that represent the limits of the current and historic range and/

or that appear to be restorable and thus good sites for reestablishment projects. Based on these

criteria, some proposed core areas were expanded, some were omitted, and new areas were

added.

In 2001, a new population of California red-legged frogs was located in a watershed adjacent

to Traverse Creek. This highlights the need for additional surveys and the opportunities for

recovery implementation in all core areas listed in the recovery plan. In light of this new

sighting, we feel that it is important to keep selected core areas until adequate surveys and

habitat suitability assessments are conducted.
Recovery Plan for the California Red-legged Frog 171

Outline of Recovery Actions

Comment: Three commenters suggested that recovery actions should focus on controlling

predation rather than increasing habitat and protecting habitat.

Response: The recovery plan emphasizes the need to control predation as a means of

recovering the California red-legged frog. At the same time, emphasis is put on the

development of watershed management plans to meet the recovery needs at the watershed

level and thus allow for customized, site-by-site management. It is in these watershed

management plans that predator control can be focused and implemented, where appropriate.

Where the preparers were aware of heavy predation, these watersheds were included in the

stepdown narrative of recovery tasks and specified in the Guidance for Development of

Watershed Management Plans and Implementation of Recovery Tasks. We urge land

management agencies to manage non-native predatory species on their lands and is willing and

eager to provide technical assistance and will consider funding any proposal regarding removal

of non-native, predatory species.

Comment: Include as a recovery task the control, research, and monitoring of native

predators.

Response: The recovery team did not wish to list removal of native predators as a task needed

for recovery. Some recovery actions, however, will reduce the impacts of predation. For

example, relocating picnic grounds and campsites farther away from known California redlegged frog habitat will reduce the proliferation and concentration of native predators such as

raccoons. Further, when the ecosystems in which California red-legged frogs live are restored

to ecological health, a balanced species composition is likely to be restored and will thus

reduce the extent and effects of predation by native species.

Comment: Emphasize the need for research on the role of contaminants and the decline of

California red-legged frogs.

Response: There is an extensive list of research needs and land management recommendations

described in the stepdown narrative of the recovery plan and the Guidance for Development of

Watershed Management Plans and Implementation of Recovery Tasks. A large portion of these

outstanding needs and recommendations deal specifically with contaminants.

Implementation Schedule

Comment: Several commenters suggested that the costs for recovery are underestimated.

Response: These estimates represent best available information from various analyses that

estimate costs for implementing recovery actions. As the recovery plan is implemented, the

exact costs will become more apparent.

Comment: Many commenters expressed concern about actions proposed in the recovery

plans that could affect private landowners.

Response: A recovery plan is not a regulatory document and does not provide for agreement to

or implementation of any of the recovery tasks proposed. A recovery plan is a reference

document that identifies actions that, if implemented, are expected to recover the species. Any

actions that are implemented must follow appropriate State, local, or Federal laws and

regulations. Any cooperation from private landowners is voluntary. Specific arrangements for
172 Recovery Plan for the California Red-legged Frog

accomplishing recovery actions would be worked out at the time of planning and

implementing the action and should include all appropriate stakeholders.

Appendices

Comment: Include safe harbor provisions.

Response: A Safe Harbor Agreement is a voluntary agreement between us and one or more

private or nonfederal landowners to restore, enhance, or maintain habitats for listed species,

candidates, or other species of concern. Under the Agreement, the landowner would be

provided assurances that we would not impose additional land use actions. If the Agreement

provides a net conservation benefit to the covered species and the landowner meets all the

terms of the Agreement, we would authorize the incidental taking of covered species to enable

the landowner to return the enrolled lands to agreed upon conditions.

The recovery plan recommends the use of Safe Harbor Agreements for the conservation of the

California red-legged frog. Such agreements are seen as a valuable tool that can be used to

implement the recovery plan. Discussion of Safe Harbor Agreements has been added to the

plan in Appendix E. which addresses incentives for recovery implementation.

Comment: Include a section on 10(J) for reintroduction.

Response: Because reestablishment of California red-legged frogs in portions of its range is

recommended in the recovery plan, a description of section 10(J) of the Endangered Species

Act has been added to Appendix G. which provides information on reestablishment

opportunities and methods.

Comment: The boundaries of core areas should be refined and the maps of core areas should

be clearer.

Response: Revised maps are included in Appendix C. Due to budget limitations, color maps

and large maps are kept to a minimum in the recovery plan. Because of this, the maps are not

as clear and refined as we would like. If any member of the public is interested in seeing maps

of better clarity, they may visit the Sacramento Field Office to view the maps on file.
Recovery Plan for the California Red-legged Frog 173

❝ You never see a frog so modest and straightfor'ard

as he was, for all he was so gifted. And when it come

to fair and square jumping on a dead level, he could

get over more ground at one straddle than

any animal of his breed you ever see.❞

—Mark Twain, Celebrated Jumping Frog of Calaveras

County