California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 1

CALIFORNIA RED-LEGGED FROG WORKSHOP

Norman Scott & Galen Rathbun

ACKNOWLEDGEMENTS

California Department of Transportation

U. S. Fish and Wildlife Service

U. S. Geological Survey

California State Parks

Grey HayesElkhorn Slough Coastal Training

Program

Dana BlandGranite Rock Sand Plant

SCHEDULE

WEB SITE

DOCUMENTS

IMPORTANT POINTS• Water regimes -- Mediterranean

climate• Population dynamics• Agriculture -- cattle and ponds• Manage larval survival• Manage populations, not individuals• Clear management objectives

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 2

Identification

Foothill Yellow-Legged

Frog

Rana boylii

Mountain Yellow-Legged FrogRana sierrae

Pacific Chorus Frog

Pseudacris regilla

BullfrogLithobates

catesbeianus

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 3

Bullfrog

California Red-Legged Frog

CaliforniaRed-Legged

Frog

California Red-Legged

Frogs

Variation

Light and Dark Colorful

Individuals

Colorful With Little Pattern

Male vs. Female

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 4

Egg MassesGOSNER

EMBRYO/TADPOLE STAGING SYSTEM

Stage 1 = Undivided fertilized eggStage 26 = Hind leg bud apparentStage 46 = Metamorphosis complete

Gosner 1960. Herpetologica 16:183-190.

California Red-Legged Frog California Red-Legged

Frog

Tadpole Identification

BODY PROFILES

Tree Frog Red-Legged Frog

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 5

Bullfrog Tadpole BULLFROG TADPOLES

Hatch April to SeptemberProbably overwinter at least onceAre usually greenish or yellowAlways have dots or “freckles”

Are almost never the same size as contemporaneous red-legged frog tadpoles

Red-Legged Frog and BullfrogTadpoles

Bullfrog

CALLIDENTIFICATION

(Davidson 1995)

DISTRIBUTION

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 6

TERMINOLOGYAdultAge

EmbryoFroglet

JuvenileLarva

MetamorphTadpole

RECENT TAXONOMIC CHANGES

Pacific Chorus Frog (Tree Frog)Hyla regilla >> Pseudacris regilla

Western ToadBufo boreas >> Anaxyrus boreas

BullfrogRana catesbeiana >> Lithobates

catesbeianusCalifornia Red-Legged Frog

Rana aurora draytonii >> Rana draytonii

RANA DRAYTONII PHYLOGENY

Rana aurora• males to 65 mm, females to 93 mm• males lack vocal pouches• often calls underwater• eggs often placed deep

Rana draytonii• males to 116 mm, females to 138 mm• males with vocal pouches• never calls underwater• eggs placed near surface

BIBLIOGRAPHY

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 7

MEDITERRANEAN

CLIMATE

Mediterranean Climate

Stream FlowExtremes

Flow Extremes

San Simeon - Summer San Simeon - Fall

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 8

San Simeon - Winter San Simeon - Spring

Calm and Stable Water

forEgg Laying BIOLOGY

ANNUAL CYCLEYear 1December-April.......................Calling and Egg LayingJanuary-September................Tadpole Stage*June-September......................Metamorphs Appear*June-November.......................Juvenile Period

Year 2.......................................Juvenile Period

Year 3December-April........................First Breeding

(males and some females)

Duration of Stages•Calling: 1-2 months•Egg: 2-3 weeks•Tadpole: 4-6 months usually,

some to 1 year•Juvenile: 20-32 months•Adult: maximum 7 years +

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 9

Fresh Egg Mass

Egg Clusters

Newly Hatched TadpolesCalifornia

Red-legged Frog

MetamorphosisJuvenile

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 10

AdultTADPOLE FOOD

“Aufwuchs”Algae, fungi, microscopic

animalsCarrion

FROG FOODArthropods

MolluscsAnnelid worms

Largest frogs include fish, other frogs, mice

SIZE AND WEIGHT

Age - Size Weight - Length

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 11

POPULATION

MODEL

EIGHT-YEAR STUDY

Populations in four coastal streams

San Luis Obispo County

SURVIVORSHIP

Stage Age Survival(months)

•Egg>>metamorph 0-5 1-5%**

•Metamorph>>juvenile 5-12 10%

•Juvenile>>adult 12-24 33%

•Adults 24-80+ 33%/year

Rana draytonii Survivorship

0100200300400500600

1 2 3 4 5 6

Year

Num

ber o

f Fro

gs

Roughly..........

The average female only breeds once

and

One egg mass (1000-4000 eggs) will produce 1 breeding pair

HABITATS

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 12

Habitats – Cattle are Important Habitat – Dams are Important

Cattle and Dam Cattle and Dam

Stock Pond Stock Pond

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 13

Spring Box

Treated Wastewater Storage

Percolation Pond Dunes Pond – No Cattle No Dam

Riparian Upland Habitat

MOVEMENTS

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 14

MOVEMENT STUDIES

Personal Observations (1993-9) San Luis Obispo Co.

Bulger et al. (2003) Santa Cruz Co.

Fellers & Kleeman (2007) Marin Co.

Tatarian (2008) Contra Costa Co.

INTERPRETING MOVEMENT STUDIES

Length & seasonality of study

Habitat characteristics

Adversity factors

MovementsBreeding, Dispersal, and Avoiding Adversity

Pico Creek Radio Tracking

San Simeon Creek Radio Tracking

Dispersing Juvenile Frogs

???

Establishing a Pattern?

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 15

SCOTT CREEKRADIO TRACKING

Scott Creek Valley

POPULATIONBIOLOGY

POPULATION TERMINOLOGY

•LOCAL POPULATION--Frogs in habitats linked by the regular exchange of propagules

•METAPOPULATION--Two or more local populations rarely linked by migrating individuals

•ISOLATED POPULATION--A local population not exchanging propagules with any other local population

THE GEOGRAPHY OF EXTINCTIONS

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 16

Extinction Sequence

•Metapopulation linkages are broken, creating isolated local populations

• Local populations lose mosaic of local habitats

•Local populations go extinct

Isolated populations will not

persist without managementTHREATS

Threats

• Urban Influences • Agricultural

Influences • Exotic Predators • Natural Predators• Disease 89 Winter Road Surveys

1994, 1995, 199739 Frogs, ~ 90% deadR. Seymour & M. Westphal unpubl. data

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 17

Urban Impacts

Bridges &Culverts

Water Regimes & Barriers

Disappearing Water

Barrier Mortality

Agricultural Impacts

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 18

Cattle & Vegetation Exotic Predators

IntroducedCentrarchidFishes –Bluegill &Largemouth bass

Native Predat

ors AGRICULTURAL CHEMICALS

CHYTRID FUNGUS

RANAVIRUS

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 19

MANAGEMENTFISH & BULLFROG

CONTROL

“Skinny legs!...I got skinny legs!”D’Amore et al. (2009)

Factor Bullfrog Red-Legged Frog

Higher temperature 0 +Higher pH 0 +Constructed pond 0 +Pond isolation 0 +Distance to agriculture 0 -Percent cultivated 0 +

CONSTRUCTION ANDMANAGEMENT

OF HABITATS

STOCK POND

MANAGEMENT

See Handout

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 20

ManagingFrog

Ponds

Cattle Fence

Constructed Breeding Pond - Failed Constructed Pond – Successful Breeding

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 21

Constructed Summer Habitat

Golf Course Ponds

Buffer Zones

SCORING PONDS AND

SMALL STREAMS AS

BREEDING HABITAT

TRANSLOCATION

Guadalupe Oil Field

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 22

HomingNo Home

RE-ESTABLISHING A POPULATION

Pinnacles National Monument

Bear Gulch Reservoir

BEAR GULCH RESERVOIR HISTORY

1934 Reservoir completed1960s-70s Red-legged frogs present

~1980 Catfish introduced1985 Drained, catfish removed198?-2000 Frogs absent2001 Re-establishment started

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 23

CHALONE CREEKWet Season

CHALONE CREEK RED-LEGGED FROG EGG

MASSES

1998 0

1999 >5

2000 7-8

•COLLECT 20% OF EGG MASSES FROMCHALONE CREEK

•HOLD TADPOLES IN HEADSTARTBOXES IN RESERVOIR

•RELEASE TADPOLES INTO RESERVOIR

RE-ESTABLISHMENTPROGRAM

NUMBER OF EGG MASSES AND

TADPOLES RELEASED

YEAR CHALONE CREEK TADPOLES EGG MASSES RELEASED

2001 5 116++2002 9 9142003 3 841

TOTALS 17 1871++

RESULTS (1)

YEAR TADPOLES METAMORPHS ADULTS ANDRELEASED JUVENILES

2001 116++ 17 0

2002 914 154 12

2003 841 427** 29

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 24

RESULTS (2)YEAR METAMORPHS ADULTS AND

JUVENILES2001 17 02002 154 122003 427 29------------------------------------------------2004 485 202005 317 122006 329 222007 68+ 15+2008 206 14

IMPORTANT POINTS• Water regimes -- Mediterranean

climate• Population dynamics• Agriculture -- cattle and ponds• Manage larval survival• Manage populations, not individuals• Clear management objectives

U.S. FISH AND WILDLIFE SERVICE

Site Assessment & Survey ProtocolRecovery PlanCritical Habitat

TECHNIQUES

BIBLIOGRAPHY

SURVEY EQUIPMENTMOST SURVEYS

WadersHeadlamps

Dip NetsData Recorder

SPECIAL CIRCUMSTANCESFloat tubesSpotlightsBinoculars

Tadpole Traps

“See, Frank? Keep the light in their eyes and you can bag them without any trouble at all”

California Red-Legged Frog Workshop 2009

Galen Rathbun and Norman Scott in cooperation with the Elkhorn Slough Coastal Training Program 25

LIGHT SOURCES FOR

EYE-SHINE SURVEYS

EQUIPMENT

SUPPLIERS

Questions?