Recovery Planfor the Pacific Pocket Mouse( P e r o g n a t h u s longimembris pacificus)*

Pacific PocketMouse(Perognathus iongimembrispacificus)

RecoveryPlan

Publishedby the U.S. Fish& Wildlife Service

Region 1

Portland,Oregon

Preparedby

Phillip Bryiski, Ph.D.

LorenHays

JonAvery

Approved:

Region 1, U.S. ish andWildlife Service

Date:I &

DISCLAIMER

Recoveryplansdelineateactionsrequiredto recoverand/orprotectlisted species.

We (theU.S. Fishand Wildlife Service)publishplans. Sometimestheplansare

preparedwith theassistanceofrecoveryteams,contractors,Stateagencies,and

otheraffectedandinterestedparties.Recoveryteamsserveasindependent

advisorsto us. Plansarereviewedby thepublic andsubmittedto additionalpeer

reviewbeforetheyareadoptedby us. Objectivesof theplanwill be attainedand

any necessaryfundsmadeavailable,subjectto budgetaryandotherconstraints

affectingthepartiesinvolved,aswell astheneedto addressotherpriorities.

Recoveryplansdo notobligateotherpartiesto undertakespecific tasksandmay

not representtheviewsnor theofficial positionsor approvalofany individualsor

agenciesinvolved in theplanformulation,otherthanus. Theyrepresentour

official positiononly aftertheyhavebeensignedby theRegionalDirectoror

Directorasapproved.Approvedrecoveryplansaresubjectto modificationas

dictatedby newfindings,changesin speciesstatus,andthecompletionof

recoverytasks.

LITERATURE CITATION: U.S. FishandWildlife Service. 1998. Pacific

PocketMouse(Perognathuslongimembrispac~ficus)RecoveryPlan. Portland,

OR. ll2pp.

Additionalcopiesmaybe purchasedfrom:

Fishand Wildlife ReferenceService

5430GrosvenorLane,Suite110

Bethesda,Maryland20814-2142

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

FAX: 301/564-4059

Thefee for thePlanvariesdependingon the numberofpagesofthePlan.

i

ACKNOWLEDGMENTS

We (theU.S. FishandWildlife Service(Service))wishto thankandacknowledge

the manypersonsoverthe yearswhohaveprovidedhelpful informationand

conversationrelatingto thePacific pocketmouseand/orendangeredrodent

biology andecologyin general. Dr. Phillip Brylski, LorenHays,andJonAvery

authoredthis final plan. RichardEricksonsharedvoluminousdataand

information;PeterMeserve,R.J. M’Closkey, andRichardMacMillan sharedtheir

field experiencewith theusandofferedtheirinsightson thedetection,biology,

andecologyofthePacific pocketmouse;and Jim PattonandDanWilliams

answeredquestionson thespecies’taxonomy. Mark PavelkaandArthur

DavenportoftheU.S FishandWildlife ServiceCarlsbadField Office~ Mike

Bentzienof theJacksonvilleField Office;Nick Holler oftheNationalBiological

Service;andbiological consultantsSteveMontgomery,ShanaDodd, Phil

Behrends,MichaelO’Farrell, andWayneSpencerprovidedthebenefitoftheir

experienceandexpertise. Personnelof theMarine CorpsBase,CampPendleton,

particularlySladerBuck and DaveBoyer,assistedin thecoordinationofPacific

pocketmousesurveysandprovideduseful informationandexpertise. We

acknowledgethetremendouscontributionsof specimens,journals,andfiles of the

following museums/collections:SanDiegoNaturalHistory Museum,Santa

BarbaraMuseumofNaturalHistory, NaturalHistory Museumof Los Angeles

County,Dickey CollectionoftheUniversityof California, Los Angeles,andthe

Museumof VertebrateZoologyat theUniversityof California,Berkeley.

Additional collectiondataweresuppliedby theU.S.NationalMuseumin

WashingtonD.C., UniversityofArizona,CaliforniaStateUniversity,Northridge,

andNorthernIllinois University.

ii

EXECUTIVE SUMMARY

Current Status: ThePacific pocketmouse(Perognathuslongimembris

pac~ficus)historically occurredon theimmediatecoastofsouthernCalifornia

from Marinadel Rey andEl Segundoin Los AngelesCounty,southto thevicinity

of theMexicanborderin SanDiego County. Thesubspecieshasbeenrecorded

up to approximately4 kilometers(2.5 miles)inland. Rediscoveredin 1993aftera

20-yearperiodduring which thesubspecieswasnot detected,thesubspeciesis

currently knownto occurattheDanaPointHeadlands,OrangeCounty,andtwo

locationson the MarineCorpsBase,CampPendletonin SanDiego County.

Currentoccupiedhabitatfor thePacific pocketmouseis estimatedto be lessthan

400 hectares(1,000acres)at thethreeknownlocalitiescombined.

Habitat Requirementsand Limiting Factors: ThePacific pocketmousehas

occurredon fine-grain,sandysubstratesin opencoastalsagescrub,coastalstrand,

coastaldune,andriver alluvium habitats.Theextantpopulationsat thethree

knownlocalesoccurwithin opencoastalsagescrubhabitats.Thesubspeciesis

imminently threatenedby habitatdestructionandfragmentation,documented

depredationby domesticcats,andrecreationalactivities.

RecoveryObjective: Delisting,with an interim objectiveof reclassificationto

threatenedstatus.

RecoveryCriteria: Wemay considerreclassifyingthePacificpocketmouseto

threatenedstatusif andwhen:

I. Tenpopulationsareindependentlyviable andstableor increasing,andtheir

habitatsaresecure(freeofrisk of loss)andfully protectedthroughfee

ownershipby aresourceagencyorconservationprogram,conservation

easement,or othermeansof permanentprotection. PopulationsofPacific

pocketmice shallbe consideredviable if theappropriateanalysisof

measuredpopulationparametersindicatethat eachofthe 10 populationshas

a 95 percentorgreaterchanceof surviving for 100 years.

iii

2. Occupiedhabitatconsistsof aminimumof2,000hectares(4,940acres)thataresecureand fully protectedthroughfeeownershipby aresourceagency

or conservationprogram,conservationeasement,or othermeansof

permanentprotection.

3. All Pacific pocketmousepopulationsaremanagedthroughaprogramto

maintaingeneticdiversity for futuregenerations.

4. All Pacificpocketmousepopulationsandessentialhabitataremanagedso

thatcurrentandpotentialthreats(e.g.,predationanddisease)areeliminated

or minimizedto the extentthat eachpopulationis not atrisk ofextirpation.

Essentialhabitatis definedto meanboth suitableandpotentialhabitatthat

is necessaryfor thefull recoveryof thesubspecies.

We mayconsiderdelistingthePacificpocketmouseif andwhen:

1. All actionsnecessaryfor reclassificationto threatenedhavebeen

implemented.

2. Any necessaryprotection,restorationandenhancementactivities(on allsitesthat havebeendeterminedto be essentialto therecoveryofthe

subspecies)aresuccessfullycompleted.

3. Populationsof thePacific pocketmouseshouldbe representativeofthe full

(existing)geneticvariability andhistoricalgeographicalrangeofthe

subspeciesandoccurin habitatsthatcollectivelyrepresentthefull rangeof

parametersobservedanddescribedin thepastor duringprescribed,future

researchandmonitoringefforts.

Actions Neededand their costs:

1. Identif~’ andprotectall extantpopulationsandessentialhabitat. $511,000

2. Prepareandimplementmanagementplans. 2,900,000

iv

3. Enhanceandexpandoccupiedandpotentialhabitat.

4. Conductresearchon life history, ecology,andpopulationbiology.

5. Identify andimplementmeasuresto createadditionalpopulations.

6. Enhancepublic awareness.

698,000

1,053,000

2,096,000

211.000

Total $7.5 million

Thesecostsexcludelandacquisitionandother,asyet, undeterminablecosts.

Datesof Reclassification:Reclassificationto threatenedstatusmayoccurby the

year2023,assumingfull implementationof this plan. Researchandothertasks

prescribedby this planare necessaryto determinethepotential for complete

recoveryanddelisting. Accordingly,thedateofdelistingis presentlyuncertain.

v

TABLE OF CONTENTS

ExecutiveSummary 111

I. Introduction 1

SpeciesOverview I

Description 2

Taxonomy 2

Historic andCurrentRange 3

HabitatDescription 8

Life History/Ecology 10

PopulationViability 16

Reasonsfor Listing: DeclineandCurrentThreats 17

HabitatDestruction 17

HabitatFragmentationandDegradation 20

Depredation 26

ConservationEfforts: Research 26

ConservationEfforts: ManagementandProtection 27

FederalActions 27

StateandLocal Actions 30

II. Recovery 33

RecoveryStrategy 33

RecoveryObjectivesand Delisting Criteria 35

NarrativeOutline for RecoveryActions 37

III. ImplementationSchedule 71

IV. References 82

APPENDIX 1. GeneticAnalyses 97

APPENDIX 2. EssentialCaptiveBreedingProtocolElements 101

APPENDIX 3. SummaryoftheAgencyandPublicCommentson theDraft

PacificPocketMouseRecoveryPlan 108

vi

LIST OF FIGURES

Figure 1. Historic LocalitiesBasedon MuseumRecords 4

Figure2. LocationsofKnownPopulations 6

LIST OF TABLES

Table 1. Summaryof theNaturalHistory ofPerognathuslongimembris 12

Table2. ImplementationSchedulefor Pacific PocketMouseRecovery 73

vii

I. Introduction

TheEndangeredSpeciesAct (Act) callsfor preparationofrecoveryplansfor

thoselisted speciesthat arelikely to benefitfrom theeffort. A recoveryplanmust

establish,if practicable,recoverygoalsand objectives,describesite-specific

managementactionsrecommendedto achievethosegoals,andestimatethetime

and costsrequiredfor recovery.A recoveryplanpresentsa setof

recommendations.

SpeciesOverview

ThePacific pocketmouse(Perognathuslongimembrispacificus)is endemicto

thecoastof southernCaliforniafrom Marinadcl Rey andEl Segundoin Los

AngelesCounty, southto thevicinity of theMexicanborder in SanDiego

County. Thesubspeciesoccurredon fine-grain, sandysubstratesandinhabited

coastalstrand,coastaldunes,river alluvium,andcoastalsagescrubhabitats

growingon marineterraceswithin approximately4 kilometers(2.5miles) ofthe

ocean. Currently,thesubspeciesis found predominantlyon sandysubstrates

within coastalsagescrubhabitats.

We(theU.S. Fish andWildlife Service)emergencylisted thePacific pocket

mousein February1994 (59FR5306)following therediscoveryofa single

populationat theDanaPointHeadlandsin 1993. Uponexpirationof the

emergencyrule, we federallylisted thesubspeciesasendangeredon September

29, 1994, in accordancewith theEndangeredSpeciesAct (59FR 49752). We

gavethesubspeciesarecoverypriority numberof 3C whichmeansit is facinga

high degreeof threat, includingconflictswith developmentprojects,yethasa

high recoverypotential. TheCaliforniaDepartmentof FishandGamealso

designatedthePacific pocketmouseasa “SpeciesofSpecialConcern”.

In 1995, Pacificpocketmicewerediscoveredin two generallocationson the

MarineCorpsBase,CampPendleton,in SanDiegoCounty. Currentoccupied

habitatfor thePacific pocketmouseis estimatedto total lessthan400 hectares

(1,000acres)at all sitescombined. Noneof theninehistoric locales(Erickson

1

1994,Erickson1998)arepermanentlyprotectedand all havebeendamagedorare

threatenedby habitatdestructionor fragmentation,human-causedfire, orother

disturbances.Populationsat six ofthehistoric localitiesapparentlyhavebeen

extirpated.

ThisrecoveryplansummarizesthetaxonomyofthePacific pocketmouse,its

historic andcurrentdistribution,knownfeaturesofhabitatandlife history, and

thecurrentthreatsto thesubspecies.Thepresentstatusof conservationefforts on

behalfofthissubspeciesis alsodescribed.In Part II ofthis plan,

recommendationsaremadefor a long-termprogramto affect therecoveryofthe

subspecies.

Description

All membersofthefamily Heteromyidaearenocturnalgranivoreswith external,

fur-linedcheekpouches.Thebody pelageofthe little pocketmouse

(Perognathuslongimembris)is silky. Thelittle pocketmouseshowswide

geographicvariationin pelagecolor (Hall 1981). Thedorsalpelageis

predominatelybrown,pinkishbuff or ochraceousbuff. Theventralpelageis

whitish. Therearetypically two small patchesoflighter hairsatthebaseofthe

ear. Thetail canbe eitherdistinctly or indistinctly bicolored. ThePacific pocket

mouseis amongthesmallestsubspeciesof little pocketmice, rangingup to 131

millimeters(5.2 inches)in lengthfrom noseto tip oftail (Hall 1981). Little

pocketmice weigh7 to 9 grams(0.25to 0.33 ounces).

Taxonomy

ThePacific pocketmouse(Perognathuslongimembrispac~ficus)is I of 19

recognizedsubspeciesofthe little pocketmouse(Perognathuslongimembris)

(Hall 1981). This subspeciesis thesmallestmemberofthe family Heteromyidae,

which consistsofspiny pocketmice (HeteromysandLiomys),pocketmice

(PerognathusandChaetodipus),kangaroorats(Dipodomys),andkangaroomice

(Microdipodops).

2

ThePacificpocketmousewasoriginally describedby Mearns(1898)asa distinct

species,Perognathuspac~ficus,basedonthetypespecimenthatwascollectedon

theshoreofthePacificOceanat “MexicanBoundaryMonument258” in San

Diego County,California. Although von Bloeker(193la,b) initially recognized

thePacificpocketmouseasadistinct species,he subsequentlyconcludedP.

pac~ficusrepresentedtwo subspeciesof the little pocketmouse,P. longimembris

pac~ficusandP. 1. cantwelii (vonBloeker1932). Subsequentto a biometric

analysisof331 specimensofthe little pocketmouse,Huey(1 939a)recognizedP.

1. pac~ficusinclusiveofthetwo subspeciesdescribedby von Bloeker(1932). Hall

(1981)andWilliams et al. (1993)continuedto rely on that treatment.

Historic and CurrentRange

ThePacificpocketmouseis endemicto theimmediatecoastof southern

Californiafrom Marinadel Rey andEl Segundoin Los AngelesCounty, southto

the vicinity oftheMexicanborderin SanDiegoCounty(Hall 1981; Williams et

al. 1986; Erickson1993). Thesubspecieshasnot beenrecordedoutsideof

California (Williams etal. 1993;Erickson1993)andhasnot beenreliably

reportedmorethan4 kilometers(2.5miles) from theocean.Erickson(1993)

notedfurther that thePacific pocketmousehasnot beenreliably recordedabove

180 meters(600feet) in elevation,butSpencer(1997)notedthatelevationand

distancefrom thecoastarecorrelatedvaluesanddoubtedthatelevationwas

relevant.

Range-widesurveydatato dateand all otherrelevantinformationindicatethatthe

Pacificpocketmousewasandis apatchilydistributedsubspeciesthathasbeen

describedasnevercommonor rare on carefullystudiedplotsor, at best,

historically andlocally “...abundanton sandybottomsnearthecoastof SanDiego

County...” (Bailey 1939). Theavailabledataindicatethatthehistorical

distributionof thePacificpocketmousewasmuchmoreextensiveprior to the

large-scaledevelopmentof thecoastallowlandsof southernCalifornia. Between

1894and 1972,thePacific pocketmousewasrecordedfrom 9 generallocalesand

30 specificlocalities from Los AngelesCounty southto theMexicanborderin

SanDiegoCounty(Figure 1) (Erickson1998). Prior to therecentdiscoveryor

3

Source: Adapted from Erickson, 1993; Enckson 1994.

Legend(134: 1894-1932)

Years collectedIndividuals inmuseum collection

Figure 1. Historic localities, basedon museumrecords.

4

rediscoveryoftheextantpopulationsatthethreeknownlocales(Figure2),

approximately80 percentof all Pacific pocketmouserecordswerefrom 1931 or

1932(Erickson1993).

Therearethreehistoric localitiesfor thesubspeciesin Los AngelesCounty:

Marinadel Rey/El Segundo,Wilmington, andClifton. Therehavebeenno

recordsof Pacific pocketmice from Los AngelesCountysince1938(Erickson

1993;Brylski 1993). ThePacific pocketmousehasbeenconfirmedat two locales

in OrangeCounty: theSanJoaquinHills and DanaPoint. Theonly knownextant

Pacificpocketmousepopulationin OrangeCountyoccurson theDanaPoint

Headlands,a historic Pacific pocketmouselocality that wasdiscoveredin the

1930’s. ThePacific pocketmousewasknownhistorically at four localitiesin San

DiegoCounty: SanOnofre,thevicinity oftheSantaMargaritaRiverEstuary,

PenasquitosLagoon,andthe lower Tijuana RiverValley (Erickson1994,

Erickson1998). Figure 1 depictsthehistoric localitieswhereindividuals were

collectedfor museumresearch,or, in thecaseof “SpyglassHill” in Newport

Beach,whereresearchwasconductedon rodentcommunityecology(Meserve

1972;M’Closkey 1972).

In 1993,presence/absencesurveysresultedin thecaptureof 25 to 36 individual

Pacific pocketmice at DanaPoint Headlands,spreadoverapproximately1.4

hectares(3.5 acres)of occupiedhabitat(Brylski 1993). Twenty-oneindividual

Pacific pocketmice were capturedat DanaPointHeadlandsin 1997on

approximately2.8 hectares(6.8 acres)of occupiedhabitat(U.S. FishandWildlife

Service1998).

Two locationswith extantPacific pocketmousepopulationswerediscovered(or

rediscovered)in 1995 on theMarine CorpsBase,CampPendletonin thevicinity

oftwo historic locales. Onelocationconsistsof two separatesmall pocketsof

animalsdetectedimmediatelynorth andsouthof SanMateoCreek. Thenortherly

site,which hasbeendesignatedby CampPendletonastheSanMateo-NorthSite

(“SMN”), is approximately1 .4 kilometers(0.9mile) from thecoast. The

southerlysite, which hasbeendesignatedastheSan Mateo-SouthSite(“SMS”),

is approximately2.1 kilometers(1.3miles) from thecoast. Presence/absence

5

LOS ANGELESCOUNTY

ORANGECOUNTY

K r

7

Dana Point:42 individuals ‘N

captured on 3.75acres in 199321 individualscaptured on 6 8 -

acres in 1997.

North of San Mateo Creek37 individuals on 2 acresin 1995.

Area shown on map

South of San Mateo Creek~:10 individuals on undeterminedarea in 1995.20 individuals on 32 acresin 1996.

RIVERSIDECOUNTY

/

• ~‘ Marine Corps BaseV Camp Pendleton

SAN DIEGOCOUNTY

North of Santa Margarita River;54 individuals on an area possibly ~as large as 865 acres in 1995.

N urirrEn STATES ___- MEXlC0

Source: U.S. Fish and Wildlife ServiceBrylski (1993, unpublished data)

Minimum numberofindividuals known to occurat time of Survey.

** North and South San Mateo Creek,map represent a single population.

6

Figure 2. Locations ofknown populations

N

/

I

10 0 10 20 Miles

surveyshavebeenperformedin muchof this areaaswell aspreliminarywork

aimedat determiningif thetwo SanMateo groupsareconnectedor distinct (MBA

andLSA 1996; MBA 1997;OGDEN 1997). Twenty individualPacificpocket

micewerecapturedin 1996at theSanMateoSouthsiteon approximately13

hectares(32acres)of occupiedhabitat;37 individualswerecapturedin 1995at

theSanMateoNorthsite on approximately6.5 hectares(16acres)ofoccupied

habitat(OGDEN 1997). Thesesurveysweredesignedto determineonly the

presenceor absenceofthePacific pocketmousein specificareasanddid not

employthemoreintensivemethodsnecessaryto determinepopulationnumbersor

demographics(OGDEN 1997).

Studiesto definitively determinetherelationshipbetweenthesetwo groups(e.g.,

degreeofexchangeof geneticmaterial)arenot yet conclusiveandwill takemore

time andeffort to completethanany of thestudiesconductedto date,especiallyif

standardlive trappingtechniquesareemployed(M. Pavelka,pers.comm. 1998).

Any movementoccurringbetweenthesetwo groupsprobablyis naturallysporadic

andinfrequent -- somethinglimited surveyswouldnot likely detect. Some

impedimentsto movementnow exist, includinga roadway,cultivatedagricultural

lands,andSanMateoCreekwash. Consistentoccupationofthe SanMateoCreek

washor a “connectingcorridor’t is unlikely to occurundercurrentconditionsas

Pacific pocketmicearenotJikely strongcolonizersandprobablycouldnot

maintainapresencein areassubjectto periodicoverwash/floodingorother

continualdisturbances(i.e., agriculture)(M. Pavelka,pers.comm. 1998).

Nevertheless,periodicmovementbetweengroupsacrossthewashmayoccurin

the long term. As a result, linkagebetweenthesegroupsmayprovenecessaryto

maintaingeneticintegrity,allow for habitatdynamicsandecosystemfunction,

andprovidefor recolonizationshouldonegroupbecomeextirpated.

Thesecond,separateCampPendletonlocalewith an extantpopulationoccurson

amarineterracenorth of theSantaMargaritaRiver in an areathat is designatedby

CampPendletonastrainingareaOscar-i. Theextentof occupiedhabitatin the

Oscar-Itrainingarearangedfrom approximately2.5 to 4 kilometers(1.6 to 2.5

miles)from thecoastin 1996(U.S. FishandWildlife Service,unpublisheddata).

Fifty-four individual Pacific pocketmice werecapturedin 1995attheOscar-I

7

site,estimatedto possiblybe aslargeas350 hectares(865 acres)of occupied

habitat(OGDEN 1997). Surveysof thecoastalareabetweenthetwo known

localeswith extantpopulationson CampPendletonhavealmostbeencompleted

andno additionalpopulationshavebeenfound(Buck 1997). Although

supportingdataarepresentlylacking,both CampPendletonlocaleswith extant

populationscouldbe partof a metapopulationoperatingin the longterm with

populationsoccupyingadynamicmosaicofhabitats. EventhoughthePacific

pocketmouseappearsto be extirpatedfrom suitablepatchestoday,it doesnot

necessarilymeanthatthesepopulationsdo not functionasametapopulation.

Given thetemporalmosaicof suitableandunsuitablepatchesthroughoutthis

subspeciesrange,it appearsmorelikely that they functionedasa classic

metapopulation(A. Davenport,pers.comm. 1998). Thelocationsandrelative

sizesoftheextantpopulationsatthethreeknownlocalesaredepictedin Figure2.

Fewerthan 1 50 individualmice (whenrecapturesareconsidered)werelive-

capturedatthesesites from 1993 to 1997. Numerousrecentsurveyswithin the

historic rangeof thesubspecieshavefailed to detectadditionalextantpopulations

(U.S. FishandWildlife ServiceI 994c; U.S. FishandWildlife Service,

unpublisheddata;OGDEN 1997,SAPPHOS1997). Giventhesmall numbersof

knownpopulations,thesmall areaknownto be currentlyoccupied,andtotal

individual animalscapturedto date,thePacific pocketmouseremainshighly

endangeredand vulnerableto extinction.

HabitatDescription

Pacificpocketmice occuron fine-grain, sandyor gravelly substratesin the

immediatevicinity of thePacific Ocean(Mearns1898;von Bloeker 193la, b;

Grinnell 1933; Bailey 1939). Although individual Pacific pocketmice havebeen

collectedor observedin severalplantcommunities,thesubspecieshasnarrow

habitatrequirementsand typically occurson sandysoils. ThePacific pocket

mousewasknownto inhabit coastalstrand,coastaldunes,river alluvium,and

coastalsagescrubgrowingon marineterraces(Grmnnell 1933;Meserve1972;

Erickson 1993),however,recentsurveyefforts havefoundthesubspeciesin

sandysubstrateswithin coastalsagescrub.

8

Specifichabitatdescriptionsfor variouslocalities areasfollows:

(1) SpyglassHill, SanJoaquinHills, OrangeCounty: Thehabitatoccupiedby

thepopulationof P.1. pac~ficusstudiedby Meserve(1976b)comprisedopen

sand(26.1 percent),perennialshrubs(59.9percent),grasses(11.6percent),and

forbs(2.4percent).

(2) TijuanaRiver Valley, SanDiegoCounty: Therearethreeaccountsofthe

area.Mearns(1898)notedthatthetype specimenwascapturedon “...a flat,

oftensubmergedby high oceantides,at themouthoftheTijuanaRiver,where

it appearsto be abundant. Recountinghis discoveryofapopulation,von

Bloeker(193Ia, b) recordedthefollowing: ‘The mistakewasmadeof trying

to trapfor P. pacificuson theoceanshorein the immediatevicinity of

MonumentNo. 258.” Instead,he foundthemin aneighboringfield: “This

field gavetheappearancefrom theroadofbeingcoveredby adensegrowthof

weedsand brush. However,afterI enteredthefield, smallopenspacesof

alluvial river-bottomsandwereencounteredthat makean ideal situationfor

pocketmice. Two seriesof pocketmiceweretakenfrom threeseparatefields

in thebed oftheTijuanaRivernearits mouth. In two ofthefields, fox-tail, or

barleyweed(Hordeurn murinurn), saltgrass(Distichilis spicata),iceplant

(Mesembryanthernurncrystal/mum),starthistle (Centaureamelitensis),and

telegraphweed (Heteroihecagrand~fiora)werethepredominatingplants. In

theotherfield, arrow-weed(Plucheasericea),telegraphweed,saltgrass,ice

plant, andCroton cal~fornicuswerethepredominatingplants.” Bailey(1939)

describedthePacific pocketmouseas“abundanton sandybottomsnearthe

coast”.

(3) Oceanside,SanDiegoCounty: ThePacific pocketmousewasformerly

found “...amongthesanddunesalongtheshorenearOceanside”wherethe

animalswereapparentlyabundantovertheir restrictedhabitat. Burrowswere

noted ‘under theedgesof creepingvegetation’. “None wasdiscoveredin the

high hardclay soil backof thebeaches”.Theburrowsweresimpleandended

in a small cavity or nestchamberafoot or so belowthesurface(Bailey 1939).

9

(4) DanaPointHeadlands,OrangeCounty: Pacific pocketmice at this locale

weredetectedin opencoastalsagescrubdominatedby Artemisiacalifornica,

with fine, sandysoil with baresandyareas(Brylski 1993). Exposedsandysoil

covered13 percentof thesurfaceareain occupiedhabitat(Brylski,

unpublisheddata).

ThePacific pocketmice foundin theOscar-I areaon CampPendletoncurrently

occurin non-coastalsagescrubhabitats,includingnon-nativegrasslandsand

disturbedareasdominatedby filaree (Erodiumsp.). Anecdotalevidencesuggests

thattheareasof densegrasslandsarenot occupied(to a level ofbeingdetectable

during surveys),but thesmall coastalsagescrub,bareground,andlow density

non-nativegrasslandpatcheswithin themoredensegrasslandsareoccupied.It is

unclearwhetherthemice occupythedensegrasslandsin low numbers,usethem

only for movementto/from thesmallerpatchesof suitablehabitat,or only move

acrossthoseareasfollowing burnevents(which are quite frequentwithin Oscar-l)

whenthevegetationis lessprohibitiveto movements.ThePacific pocketmouse

alsoexploits thefriable (easilycrumbled)soils in bermscreatedduring road

maintenancein this area. It appearsthat theoccurrenceofthePacific pocket

mouseis closelyassociatedwith looseor friable soils thatpermitburrowing(M.

Pavelka,pers.comm. 1998).

Life History/Ecology

Table I summarizesbasicinformationon thenaturalhistoryofthePacificpocket

mouseandotherP. longimembrissubspecies.Few studieshavebeenconducted

on theecologyand life historyof thePacificpocketmouse. However,the

attributesofthe little pocketmouse(P. longimembris)andtheavailabledatathat

pertainto thePacific pocketmousesuggestthat thesubspeciesis facultativelyor

partially fossorial,relatively sedentary,primarily granivorous,and ableto become

torpid, estivate,or hibernatein responseto adverseenvironmentalconditions

(Bailey 1939;Kenagy1973).

Little pocketmice areamongthesmallestmammalsknownto hibernate.They

hibernatein winter(O’Farrell 1974), typically from Septemberto April. In

10

contrastto otherhibernatorsthat accumulatefat reservesfor hibernation,little

pocketmice feedon seedcachesstoredin theirburrows. Individualsbecome

torpid whendeprivedoffood for 24 to 36 hours. Duringhibernation,thebody

temperatureof pocketmice is slightly abovethat of, andvariesdirectlywith,

ambienttemperature(BartholomewandCade1957). Periodsof dormancyhave

neitheradaily or strictly seasonalpattern. In captivity, dormantindividualsmay

showsomeactivity eachday within their burrows. Emergencefrom hibernation

in spring(typically in March) correlateswith availability offorb andgrassseeds

(Meserve1976b).

Relatively little is knownofthebreedingbiology of Pacific pocketmice.

Meserve(1972)notedthat pregnantand lactatingfemaleshavebeenfoundfrom

April throughJunewith immaturesnotedfrom JunethroughSeptember.Brylski

(1993)observedlactatingfemalesin Julyof 1993 on theDanaPointHeadlands

andnotedthattwo litters were produced.Oneor moreof thejuvenilesin the

DanaPoint Headlandspopulationwereconsideredto havelimited reproductive

capabilities(Brylski 1993).

11

Table 1. Summaryof the NaturalHistory ofPerognathuslongimembris

Food Habits

P. longimembrispac~ficus: Pacific pocketmicepreferseedsandstemsofgrassesandsomeforbs(Meserve1 976a);arthropodsandlarvaareeatensomewhat(vonBloeker1931;Meserve1972; Meserve1976a). Bailey (1939)recordedseedsof thefollowing speciesfromthepouchesofcollectedspecimens:“Lotus prostratus,two speciesofsaltbush,heliotrope,mustard,Monanthochloe,Franseria,arush...” From thepouchesofcollectedspecimens,von Bloeker(in Bailey 1939)recordedtheseedsof Heterothecagranc4flora,Chrysothamnus,Centaureamelitensis,Croton californicus,Plucheasericea,andHordeummurinum. P.?.pacificuswasobservedto drink waterregularlyin captivity (Bailey 1939).

OtherP. iongimembris: P.?. longimembristypically foragein andadjacentto clumpsofvegetation(Brown andLieberman1973).

Activity

P. iongimembrispac~ficus:apparentlyhibernatesin winterand generallyremainsinundergroundburrowsfrom Novemberto February(Meserve1972).

OtherP. iongimembris: Kenagy(1973)observedthat little pocketmice maystayin theirburrowscontinuouslyfor up to 5 monthsin winter, alternatingbetweenperiodsofdormancyandfeedingon storedseeds.Periodsof dormancyapparentlymaybe inducedby’, orcorrelatedwith, foodshortage(Kenagy1973). In theOwensValley, theactivity ofP.?.iongimembrisdifferedin threeconsecutivewinters, rangingfrom 0 to S monthsof inactivity(Kenagy 1976). In 1969-70,theyearof greatestsurvival (82percent)andthelargestpopulationnumber(27) for this group,theywere activeall winter. Precipitationin theseasonprior to the 1969-1970winterwasthreetimesnormal,andplantsproducedaprolificcropofseeds.This populationwasactive foragingabovegroundduringadifferentwinterfollowing poorseedproduction,althoughit is notclearthatall individualswereactive. Lessfit individualsandyoungof theyearmaybe forcedinto winter activity dueto low foodstores.In thesamestudy,maleswereobservedin thespringbeforefemales. Wintersarelessseverein therangeof Pacific pocketmousethanof othersubspecies,whichmay explain(andpredict)somedifferencesin activity patterns(Spencer1997).

12

Table 1. Summaryof theNaturalHistory of

Perognathuslongimembris

(Continued)

Density and Movements

P. longimembrispac~ficus:Thirty-six animalswerecapturedin approximately1.4 hectares(3.5acres)ofoccupiedhabitaton theDanaPointHeadlandsin 1993(Brylski 1993). Ogden(1997)reporteda movement(by recapture)ofabout22 meters.Most otherrecapturesareatthefirst capturelocation(Spencer1997). Twenty individual Pacific pocketmice werecapturedin 1996attheSanMateo Southsiteonapproximately13 hectares(32acres)ofoccupiedhabitat;37 individualswere capturedin 1995at theSanMateoNorthsiteonapproximately6.5 hectares(16 acres)ofoccupiedhabitat(OGDEN 1997).

OtherP. longimembris: Little pocketmice are oftenthemostabundantrodentin aridhabitats.Hall (1946)estimatedapopulationdensityin Nevadato be ashigh as990individuals/hectare(400individuals/acre).Homerangesrangedin sizefrom 0.12 to 0.56hectares(0.30to 1.4 acres)andpopulationsrangedin densityfrom 1 to 5.5 individuals perhectare(0.4 to 2.2 individualsper acre)in JoshuaTreeNational Monument,California(ChewandButterworth1964). In Nevada,homerangesofmalesaveraged0.3 to 1.9 hectares(0.7 to 4.7 acres)andhomerangesof femalesaveraged0.5 to 3.1 hectares(1.2to 7.6 acres).Onestudiedpopulationdensityfluctuatedfrom 1 to 5.4 individuals perhectare(0.4 to 2.2individualsperacre).

Little pocketmice haverangedup to 305 meters(1,000feet)from theirburrowsin a24-hourperiod(Burt and Grossenheider1976). In theOwensValley, California, Kenagy(1973)observedmovementsof lessthan50 meters(165feet).

Populationdensitiesof P. flavusfluctuatewidely: in one Arizonastudyarea,animalswereabsentfor yearsand yet later werethemostabundantspecies.Averagerangeof movementwas62.5 meters(205 feet) (Chewand Chew1970)and theaveragedispersaldistanceduringa lifetime was202 meters(660feet)(Brown andZeng 1989). Homerangeshavebeenreportedat0.11 hectares(0.27acres)in Arizonaand0.24 to 0.63 hectares(0.6to 1.6 acres)inNewMexico; males’homerangesare largerthanthoseof females

.

13

Table 1. Summaryof thenaturalhistoryofPerognathusiongimembris

(Continued)

Reproduction

P. longimembrispac~ficus: Breedsfrom April throughJuly. A minority ofjuvenilesmaybreedwithin a monthofweaning.

OtherP. longimetnbris: Thespeciesasawholebreedsfrom Januaryto August,with apeakfrom Marchto May. Reproductionis keyedto theavailability of greenvegetation.Nestsareconstructedin theburrowwith roots, leaves,and otherorganicmaterials.Gestationisapproximately22 to 23 days,althoughextremesof 21 to 31 dayswererecordedby Haydeneta?. (1966). Youngof theyearare capableof breedingin thesameseasontheyareborn.

Longevity

P. longimembrispacificus: TwoP.?. pacificuslived about4 and6 yearsin captivity (Bailey1939). A P.?. bangsi trappedasan adult lived 3.5 yearsin captivity; whenit died it wasprobablymorethan4 yearsold (Behrends1997).

OtherP. longimeinbris: Within a populationof?. longimembrisstudiedatJoshuaTree(apparentlyP. 1. bangsi),30 percentof themarkedindividuals survivedfrom onespringtothenext(ChewandButterworth1964).

Behavior

P. longimembrispac~ficus:Observationsby Bailey (1939)and Meserve(1972)on captiveanimalsindicatethis subspecies,like otherheteromyids,is aggressivelysolitary.

14

Table 1. Summaryof thenaturalhistoryofPerognathusIongimembris

(Continued)

AgeStructure and SexRatio

P. longimembrispacificus:Age Structure: At theDanaPoint Headlandsand SanMateoCreekpopulations,61 percentand75 percentof thecaptures,respectively,were youngoftheyear(juvenilesandsubadults).Both studieswereconductedduring July and August. Despiteapotentialtrapbias(juvenilesmaybe moretrappablethanadults),theagestructureof thesepopulationsafterreproductionis dominatedby juveniles.

SexRatio: At theDanaPoint Headlands,thesexratiowas 1.1 to I (o~a~:~ ~). At theSanMateoCreekpopulation,thesexratio was 0.8 to 1.

OtherP. Iongimembris: No datafound.

Predation

P. iongirnembrispac~ficus: Housecatsareknownpredatorson theDanaPointHeadlandspopulation.

OtherP. longimembris:Little pocketmice arepreyeduponby owls, loggerheadshrikes,foxes,snakes,andferal cats.

15

PopulationViability

Populationviability is thecapacityof apopulationto persistover timeandis

influencedby bothdeterministicandstochasticfactors. Deterministicfactorslead

to long-termpopulationtrendsandmayincludesuchthingsasthe amountof

suitablehabitat,predationrates,reproductionrates,etc. Stochasticfactorsare

randomorunpredictableeventswhich maycausean instantaneousextinction, or

morecommonly,reduceapopulationto thepoint whereit entersone ofseveral

“extinction vortices”or positive feedbackloopsof biological andenvironmental

interactionsthat havefurthernegativeimpactson a population,possiblyleading

to its extinction(Gilpin and Soule’ 1986). Efforts to managea speciesor its

habitatcanalter thedeterministicfactorsbut it maybe muchmoredifficult to

ameliorateor minimize thestochasticones.

Generally,small populationsaremorevulnerablethanlargeones(Pimm 1991,

NossandCooperrider1994). NossandCooperrider(1994)identifiedfourmajor

factorswhich predisposesmall populationsto extinction:

• Environmentalvariationandnaturalcatastrophes.Unusuallyharshweather,

fires orotherunpredictableenvironmentalphenomena.

• Demographicstochasticity. Chancevariationin ageandsexratiosor other

populationparameters.

• Geneticdeterioration. Small isolatedpopulationsareproneto inbreeding

depressionandgeneticdrift or randomchangesin genefrequencies.

• Metapopulationdynamics. Many speciesaredistributedassystemsof local

populationslinked by occasionaldispersalthat wardsagainstdemographicor

geneticdeterioration.

16

Reasonsfor Listing: DeclineandCurrentThreats

AlthoughsuitablePacific pocketmousehabitatapparentlyremainsin SanOnofre

and contiguouscoastalareasof theMarineCorpsBase,CampPendleton,San

JoaquinHills, PalosVerdesPeninsula,El SegundoDunes,andat scattered

localitieselsewherein thehistoricrangeof thesubspecies,this habitatis

becomingincreasinglyscarceandlikely will continueto be destroyed,disturbed

or otherwiseadverselyaffectedby humanactivities. Williams (1986)concluded

that habitatlossesresultingfrom off-road vehicleactivities,highways,and

urbanizationlikely’ wereextensive.Erickson(1993)observedthat industrialand

agriculturaldevelopmentlikely wereadditionalfactorscontributingto thedecline

ofthesubspecies.Studiesof theeffectsof habitatfragmentationanddepredation

on small mammalpopulationssuggestfurtherreasonsfor thedeclineofthe

Pacific pocketmouse. All suchmajorthreatsdirectly or indirectly implicatedin

thedeclineofthePacific pocketmouseareindividually discussedbelow.

HabitatDestruction

Theconversionof nativehabitatsresultingfrom urban,suburban,andagricultural

developmentapparentlyis the leadingcauseofthe large-scaledestructionof

Pacific pocketmousehabitat. A recent,comprehensivereviewof thePacific

pocketmouse(Erickson1993)includedconsiderationsof thefateofconfirmed

(historically-occupied)Pacificpocketmousehabitat. Other,morerecentdata,

pertinentresearch,andanalyseshavebeenintegratedinto thefollowing account.

Thelargemajority of nativehabitatswithin thehistoric rangeofthePacific

pocketmousein coastalLos Angeles,Orange,andSanDiegocountieshavebeen

convertedto urban,suburban,andagriculturaluses(U.S. FishandWildlife

Service1993). Lessthan400 hectares(1,000acres)or 1 percentof approximately

11,340hectares(28,000acres)within 3.2kilometers(2miles) of thecoastin Los

AngelesCountyapparentlyareundeveloped(U.S. Fishand Wildlife Service,

unpublisheddata,1993). In OrangeCounty,about17,600 hectares(43,500

acres),or 81 percentof approximately21,600hectares(53,500acres)within 3.2

kilometers(2 miles) ofthecoast,havebeendeveloped(U.S. FishandWildlife

17

Service,unpublisheddata,1993). Landusesin coastalSanDiego Countyare

reportedlysimilar. OberbauerandVanderwier(1991)reportedthat 72 percentof

theoriginal coastalsagescrub,94 percentofnativegrasslands,88 percentof

coastalmixedchaparral,88 percentof coastalsaltmarsh,100percentofcoastal

strand,and92 percentof maritimesagescrubhabitatsin SanDiegoCountyhad

beenconvertedto urbanand agriculturalusesby 1988.

Although thehistoric distributionofthecoastalsagescrubelementof Pacific

pocketmousehabitatwas undoubtedlypatchyto somedegree,this condition

evidentlyhasbeengreatlyexacerbatedby urbanandagriculturaldevelopment.

All ofthepublishedliteratureon thestatusof coastalsagescrubvegetationin

Californiasupportstheconclusionthat this plant communityis one ofthemost

depletedhabitattypesin theUnited States(U.S. Fishand Wildlife Service1993).

In abroadercontext,theCalifornia floristic province,which is recognizedasa

separateevolutionarycenterby botanists,is identified by Wilson (1992)asoneof

therecognizedx\’orld “hot spots”,which aredefinedto be “...habitatswith many

speciesfound nowhereelseand in greatestdangerof extinctionfrom human

activity.” TheCalifornia fioristic provinceis theonly designated“hot spot” in

NorthAmericaandMexico (Wilson 1992).

Theavailableinformationfurthersuggeststhat thequantityof potentialPacific

pocketmouseriver alluvium substratehassignificantly declinedsincethe

subspecieswaslast recordedin numbersin the 1930’s. With few exceptions(such

astheSantaMargaritaRiver), essentiallyall of therivers andcreekswithin the

historic rangeof thePacific pocketmousearenow partiallyor completely

channelized.In manycases(e.g., Los AngelesRiver, SanGabrielRiver,Santa

AnaRiver), streamandsedimentflows areregulatedor inhibitedby dams,

reservoirsor otherwaterconservationor impoundmentfacilities (Erickson1993).

Althoughdescribedaslocally abundantin theTijuanaRiverValley environsin

southwesternmostSanDiegoCountyby Mearns(1898)andBailey (1939),the

Pacificpocketmousehasnot beendetectedatthatlocale since1932despite

recent,repeatedattemptsto locatean extantpopulation(TaylorandTiszler 1991;

U.S. FishandWildlife Service1994a,c;U.S. Fishand Wildlife Service1995a,b;

18

Montgomery1995). And, althoughsmallpopulationshavebeendiscovered

furthernorth in SanDiego Countyin uplandareasneartheSantaMargaritaRiver

andnearSanMateo Creek,recent,intensesurveyeffortsatthehistorically

occupiedvicinity ofthe SantaMargaritaRivermouthsimilarly did notresult in

any Pacificpocketmousedetections(OGDEN 1997;Salata1981;U.S. Fishand

Wildlife Service1 994c;Zembal1984). During the 1930’swhenPacificpocket

mice weredetectedatthemouthoftheSantaMargaritaRiver, theMarineCorps

Base,CampPendletondid notexist. ThesouthernhalfoftheSantaMargarita

River Estuarywasdestroyedin theearly 1940’sduring theestablishmentofCamp

Pendletonandtherelatedconstructionofaboatbasinandharborfacilities. In

addition, theadjacentOceansideareahasbeenextensivelydevelopedsincethe

Pacific pocketmousewaslast recordedtherein the 1930’s.

Within OrangeCounty,thePacificpocketmousehasbeenconfirmedattwo

locales: theSanJoaquinHills andDanaPoint. Developmentof the“Spyglass

Hill” areain theSanJoaquinHills beganin 1972andhasresultedin the

destructionofthesitewherethePacific pocketmouseand anumberof other

small rodentspecieswerestudiedfor a 3-yearperiod(P. Meserve,pers.comm..

1994;R. M’Closkey, pers.comm., 1994;R. MacMillan, pers.comm., 1994;

M’Closkey 1972;Meserve1972). Prior to therediscoveryofthePacificpocket

mousein 1993on theDanaPoint Headlands(Brylski 1993),the lastrecordofthe

subspecieswasfrom “SpyglassHill” in theSanJoaquinHills in 1971 (Erickson

1993). Juneto Octobertrappingefforts totaling6,411 trapnightsin theSan

JoaquinHills andadjacentLagunaCanyonin 1993 resultedin no detectionsof the

Pacific pocketmouse(Erickson,pers.comm., 1993).

ThePacificpocketmousehaspersistedon theDanaPointHeadlandsin southern,

coastalOrangeCounty. Given thedataandanalysispresentedby Brylski (1993),

it is apparentthat from 25 to 36 Pacific pocketmiceoccupiedapproximately1.4

hectares(3.5acres)ofhabitatwithin a coastalsagescrubcommunityat thatlocale

in 1993. This populationwaslocatedon landunderconsiderationfor

development(e.g.,City of DanaPoint, in litt., 1994;EDAW 1994). An April 28,

1998,approvalby theDanaPoint City Council supportedadevelopmentproposal

on the49 hectare(122acre)sitewith 28 hectares(70 acres)of thesitedesignated

19

asopenspace. TheDanaPoint Headlandspopulationis within this openspace

area,but the openspaceis currently slatedto remainprivatepropertywith

undeterminedconservationprotection.

Within Los AngelesCounty,the Pacific pocketmousehistoricallywasdetectedin

threeareas: Marinadel Rey/El Segundo/Hyperion,Wilmington,and Clifton.

Two ofthethreehistoric localesfor thePacific pocketmouse(Clifton and

Wilmington) in Los AngelesCountyhavebeendeveloped(Erickson1993). We

arecurrentlyunawareofpotentialPacificpocketmice habitatatthesetwo locales;

nonewasdisclosedor revealedasaresultof ourrequestfor information(U.S.

FishandWildlife ServiceI 994c). Thethird historic locale (MarinadelRey/El

Segundo/Hyperion)apparentlyhasbeensubstantiallyalteredsincethesubspecies

waslastdetectedthere(Erickson 1993;P. Brylski, in litt., 1993). TheHyperion

area,whichformerly containedrelatively largeexpansesofcoastalstrandand

wetlandhabitats,hasbeenextensivelydeveloped.Althoughpotentialhabitat

remainsattheEl SegundoDunes,theavailableinformationsuggeststhat it is

unlikely that thePacific pocketmousepresentlyoccursthere(P. Brylski, in litt.,

1993). TheEl SegundoDuneswithin theLos AngelesDepartmentofAirports

propertywereextensivelytrappedin 1997with negativeresults(SAPPHOS1997,

B. James,pers.comm. 1998). This trappingwasperformedin conjunctionwith

environmentalbaselinestudiesfor theLos AngelesInternationalAirport 2015

ExpansionMasterPlanProject. Therehavebeenno recordsof thePacificpocket

mousein Los AngelesCountysince1938(Erickson1993;Brylski, in litt., 1993;

B. James,pers.comm. 1998). Giventheavailableinformationatthetime,

Williams (1986)concludedthat it wasprobablethat all populationsnorthofthe

SanJoaquinHills in OrangeCountywereextinct.

HabitatFragmentationand Degradation

Habitatfragmentationis thoughtto reducehabitatqualityand increaselocal

extirpationofnativewildlife (e.g.,Tcrborghand Winter 1980;Wilcox 1980;

EhrlichandEhrlich 1981; Wilson 1992;Bolgeretal. in press;Soule’ etal. 1992).

Basedon studiesofnativebird, rodent,andflowering plant speciespersistencein

chaparralandcoastalsagescrubhabitatremnantsin coastalSanDiego County,

20

California,Soule’ et al. (1992)concludedthat “[t]he effectsof fragmentationin a

scrubhabitatin Californiaon 3 taxa(plants,birds, androdents)areconcordant.

Extinctionswithin thehabitatremnantsoccurquickly andthe sequenceof species

disappearancesof birdsandrodentsis predictablebasedon populationdensityin

undisturbedhabitat.” Terborghand Winter (1980)observedpreviouslythat

“[r]arity provesto be thebestindexof vulnerability.”

Bolgerci al. (in press)concludedthat “[fjragments supportfewerspecies[of

nativerodents]thanequivalentlysizedplots in largeplotsof unfragmented

chaparralindicatingthat local extinctionshaveoccurredfollowing insularization.”

Given a compositeoftheavailabledataon thelocal statusanddistributionof

selectspecieswithin thestudyareain coastalSanDiegoCounty, Soule’ et al.

(1992)remarkedthat it waspossibleto assesswith reasonableaccuracythedate

that aparticularhabitatremnantbecameisolated.

Soule’ et al. (1992)further notedthat “...urbanbarriersincludinghighways,

streets,andstructures,imposeavery high degreeof isolation.” Similarly, Ehrlich

andEhrlich (1981)observedthat “smalleranimalsmayalsosufferfragmentation

oftheirpopulationsby highways,railways,canals,etc.,changingpopulation

structuresandmaking theremainingpopulationssmallerandmoresubjectto

randomextinction. Onestudyhasindicatedthat afour-lanedivided highwaymay

be abarrierto themovementof small forestmammalsequivalentto ariver twice

aswide (EhrlichandEhrlich 1981). Althoughnot aforestanimal,thePacific

pocketmousemustnow be consideredrareby any standardandtherefore

vulnerableto theeffectsof continuinghabitatdestructionandfragmentation(see

TerborghandWinter 1980).

Populationpersistenceandexpansionshouldbe maintainedby precludingactions

whichresultin physicalbarriersto movement,habitatfragmentation,oran

increasein edgeeffects. All ecosystemcomponentsofPacificpocketmouse

habitatshouldbe maintainedor reestablished,includingpredator-prey

relationships,retentionof pollinators,linkageswith otherhabitatsnecessaryfor

ecosystemfunctioning,maintenanceof corridorsbetweenpotentialpopulations,

21

andprotectionof habitatcurrentlyunoccupieddueto successionalcycling of the

vegetationcommunity.

Wildfires dueto anthropogenicignitionshavecontributedto theloss,degradation,

andfragmentationofcoastalsagescrubvegetationin southernCalifornia(U.S.

Fishand Wildlife Service1993). Most of thesehuman-causedfires occurduring

thefall in conjunctionwith SantaAna wind conditions. Natural fires mostoften

likely occurredduringthe late springandearlysummer(May to June)in

conjunctionwith occasionallate seasonlightning storms(R. Minnich,pers.

comm. 1989). Lightning (an ignition source)morerarelystrikesthecoastthan

thefoothill-mountainregionandprehistoricfires probablyburnedfrom the

foothills to thecoastinfrequently(R. Minnich, pers.comm. 1989). Natural fires

nearthecoast(generallyconsistingofcoastalsagescrub)likely occurred

episodicallyand lessfrequentlythanin thefoothills (more oftencomposedof

chaparral). Coastalsagescrubis a fire adaptedplant community(Beyersand

Wirtz 1996),but unlike for chaparral,little biological justificationexistsfor

maintaininghigh fire frequencyin coastalsagescrub(Zedler1996). Coastalsage

scrubdoesnotappearto havehigh senescencerisks (thechancethat long intervals

without fire will resultin populationdeclineor local extinction)ascomparedto

immaturity risks(thechancethat populationswill be harmedby recurrenceoffire

wheninsufficient timehaselapsedfor regrowthor build up of seedreserves)

(Zedler1996). An increasedfire frequencymayfavor invasionof exoticsin

coastalsagescrub(Zedler1996).

Theseasonality,size,intensity, andfrequencyof fire in coastalsouthern

Californiahaslikely changeddrasticallyin the lastcentury(R. Minnich, pers.

comm. 1989). Most of coastalsouthernCalifornia’s remainingnaturalareasare

likely subjectto lessfrequent,aseasonal,and comparativelylarger/hotterwildfires

thanoccurredprehistorically. CampPendletonhabitatslikely sufferfrom an

increasedfire frequency,with manyfires occurringaseasonally.Although it is

truethat the largestareasofrelativelyunfragmentedcoastalsagescrubvegetation

remainon theMarineCorpsBase,CampPendleton,over6,070hectares(15,000

acres)of nativevegetation,muchof it coastalsagescrub,haveburnedon the Base

during 3 recentyearsasaresultof fires startedincidentalto military training

22

activities. Two of thesefires consumedover 2,630hectares(6,500acres)of

coastalsagescrubvegetation.High fire frequenciesandthelagperiodassociated

with recoveryof thevegetationmaysignificantly reducetheviability ofaffected

habitatsthroughoutmuchof thecurrentandhistoric rangesof thePacificpocket

mouse.

Somehabitatsthat would otherwisegenerallyremainsub-optimalfor Pacific

pocketmousemaybe repeatedlymanipulatedsuchthattheywill supportthe

taxonin theshortterm. Otherhabitatareasthat would typically (andlikely

historically did) supportoptimal habitatmaybe madeoccupiableby removalof

someperturbinginfluence(suchasreductionof exotic speciescover). A portion

oftheOscar-i populationofPacific pocketmice on CampPendletoncurrently

occursin areasthathaveburnedrecently,eitherby wildfire or controlledburning,

includingsomeareasthat havebeenburnedannuallyfor severalyears(Buck

1997). The Pacific pocketmice foundin theOscar-i areaon CampPendleton

currentlyoccurin non-coastalsagescrubhabitats,includingnon-native

grasslands,anddisturbedareasdominatedby filaree (Erodiumsp.). Anecdotal

evidencesuggeststhat theareasof densegrasslandsarenot occupied(to a level of

beingdetectableduring surveys),but thesmall coastalsagescrub,bareground,

andlow densitynon-nativegrasslandpatcheswithin themoredensegrasslands

areoccupied(M. Pavelka,pers.comm. 1998).

Little is knownof therelationbetweenfire andPacific pocketmousehabitat. Fire

of unknownfrequency,intensity,andseasonmayintermittentlycreateor sustain

Pacificpocketmousehabitatmosaics.Two of thethreelocaleswith extant

populationsof thePacific pocketmouseoccursolely in opencoastalsagescrub

habitatsandareabsentfrom adjacentpatchesofdensecoastalsagescrub.

Disturbanceto thedenseshrubcanopy,asaresultof disturbancessuchasfire,

mayimprovehabitatfor thesubspecies.In theshort term,fire in theproper

seasonand intensitycouldtemporarilyreduceshrubcanopycoveragethatmaybe

toodenseto provideoptimumhabitatfor thePacific pocketmouse(e.g.,over

muchoftheDanaPointHeadlandsand SanMateo sites). By contrast,fire could

potentiallyeliminateoccupiedhabitatfor thePacificpocketmouseandmayalso

resultin developmentofa denser(andunacceptable)understoryofnon-native

23

annualgrassesandsproutsof nativeshrubs. Previously,it wasreportedthat

increasedfire frequencymaycontributeto thetypeconversionofcoastalsage

scrubto annualgrasslandhabitats(U.S. FishandWildlife Service1993).

Currently,minimal dataareavailableto evaluatetheoverall effectsoffire on

Pacific pocketmiceortheirhabitat. We concludethatcurrentfire prevention

measuresandunnaturallyhigh fire frequenciesresultingfrom anthropogenic

ignitions maydirectly or indirectly impactthePacific pocketmouse. It will be

necessaryto evaluatethe role offire preventionandmanagementpracticesto

developmeasuresthat areconsistentwith the long-termmaintenanceofPacific

pocketmousehabitats.

Thevegetationof themarineterracesfrom DanaPointto southernCamp

Pendletontoday is heavily influencedby annualgrassesandothernon-native

species,partly in responseto exoticplantintroductionsand agriculturaluseof

theselandsduring the late nineteenthandearlytwentiethcenturies(aswell asthe

fire regimechangesnotedabove). Suchdenseexoticvegetation,in concertwith

relatively hardsoils, probablyprecludesoccupationby the Pacificpocketmouse,

whereasrelatively low densitiesof animalsmayhavehistorically occurredin the

sameareasin associationwith theoriginal, moreopen,nativevegetation.

Historic agriculturalusesappearsto havehadlasting,adverseeffectson Pacific

pocketmousehabitatfunction. Resultsof surveyson CampPendletonillustrated

apotentiallystrongnegativerelationshipbetweenknownPacificpocketmouse

distributionon Baseandareasthat havebeenfarmedin thepast(OGDEN 1997).

No Pacificpocketmousecapturesoccuredwithin theseformeragriculturalareas,

which includemanysitesthat otherwiseappearsuitable(OGDEN 1997). Oneof

thelargestblocksof highpotentialhabitatthat hasnotbeenfarmedsupportsthe

largestpopulationon Base(Oscar-I);theotherpopulationon Baseseemslikewise

restrictedto unfarmedportionsof thehighpotential soils in theSanMateoarea

(OGDEN 1997). Unfortunately,it appearsthatno extantpopulationis adjacentto

anagriculturalareathathasgonefallow, whichwould helpconfirm this potential

relationship.

24

As aconsequenceofa recentsurvey,we (U.S.Fishand Wildlife Service1994a)

reportedthat selectedhabitatsandlands in ahistorically occupiedPacificpocket

mouselocality apparentlyhavebeenadverselyaffectedby pedestrianandhorse

traffic, artificial lighting, andthepresenceofnon-nativerodentspecies.All

factorsconsidered,heteromyidrodents,including thePacific pocketmouse,may

bemore susceptibleto theadverseeffectsof thehumanpresencethancricetid

rodents(R. MacMillan,pers.comm., 1994).

Artificial night-timelighting maycauseproblemsfor nocturnalrodentssuchas

thePacificpocketmousethroughpotentialmodificationofpredationrates,

obscuringoflunarcycles,and/orcausingdirect habitatavoidance.Artificial

lighting hasthepotentialto increasetheefficiencyof predatorsandcouldhavea

negativeeffect on thePacific pocketmouse(M. Pavelka,pers.comm. 1998).

Illumination of foraginghabitatby artificial light during Pacific pocketmouse

surfaceactivity periodslikely makesdetectionby predatorseasier,potentially

increasingthepredationrateby owls, coyotes,fox,housecats,etc. Artificially lit

habitatareasmayalso be directly avoidedby Pacific pocketmousefor unknown

behavioralreasons.Artificially lit but otherwiseapparentlysuitablehabitatwas

avoidedby Heteromyidrodents(evidencedby absenceof burrows),while

adjacentunlit habitatareaswereoccupied,in a surveyperformedon Fallbrook

Naval WeaponsStation(A. Davenport,pers.comm. 1998).

Exotic Argentineantsare invadingcoastalsagescrubareasnearPacificpocket

mousehabitats.Theseantscouldhaveadversedirect or indirecteffectson Pacific

pocketmousepopulations(R. Fisher,pers.comm. 1997). Argentineantsare

knownto excludemostnativeantspeciesuponinvasionin coastalsouthern

Californiahabitats(R. Fisher,pers.comm. 1998). Ants areamajor ecosystem

componentof mostterrestrialecosystems(Wilson 1992). Argentineantscould

adverselyaffect Pacific pocketmouseindividuals(suchasnestlingmortality) and

burrowsitesdirectly. They couldalsoaffect seedproducingplants,or could

disruptkey ecosystemfunctions,including thosetypically carriedout by native

ants. Invasionof theseantsmaybe expeditedby developmentandassociated

irrigation.

25

In summary,habitatswithin thehistoric rangeof thePacific pocketmousehave

beenhighly fragmentedor degradedby highways,roads,structures,lighting, foot

traffic, otherhumanactivities,andtheproliferationofnon-nativeplant andanimal

species.Fragmentedand degradedhabitatssupportsmallerpopulations,which

aremoresusceptibleto randomextinctionevents.

Depredation

Feralordomesticcatsareoneof theexisting threatsto thepopulationofPacific

pocketmice attheDanaPoint Headlands.Feralanddomesticcatsare knownto

be efficientpredatorsof rodents(e.g.,Hubbs 1951;George1974). Pearson(1964)

concludedthattheremovalof4,200mice from a 14-hectare(35-acre)testplot

wasaccomplishedlargely by 6 catsover 8 months. FortheAnastasiaIslandfield

mouse(Peromyscuspolionotusphasma),areductionin feral catswasfollowed by

an immediateandsustainedincreasein mousepopulationdensity(Frank1993).

Phil Brylski examinedonedeadspecimenof Pacific pocketmousetakenfrom the

mouthof ahousecat(P. Bryski, pers.comm. 1998).

Othernon-nativespecies,including the red fox ( Vulpesvulpes),arealso potential

predatorsof thePacific pocketmouse. Theexplosiveproliferationofnon-native

populationsofred foxes in coastalsouthernCaliforniais well documented(e.g.,

Lewis etal. 1993). Given therelativeabundanceofthered fox in coastal

southernCalifornia(Lewis etal. 1993)and thefact that thediet ofred foxes

invariably includemice (Ingles 1965; JamesonandPeeters1988;Burkett and

Lewis 1992;Lewis et al. 1993),red foxescouldsubstantiallyimpactpopulations

ofPacificpocketmice wheretheyaresympatric.

ConservationEfforts: Research

Researchon thelife historyand ecologyofthePacific pocketmousehasbeen

limited (seeprevioussectionon life history andecology). It shouldbenotedthat

muchofthe informationconcerningthePacific pocketmousewascollected

incidentalto moregeneralrodentstudiesor is derivedfrom othersubspeciesthat

26

maynot applyto thePacific pocketmouse(e.g.,daily andseasonalactivity

patterns,homeranges,diet, etc.)(Behrends1997).

ConservationEfforts: ManagementandProtection

Theonly knownextantpopulationsofthePacific pocketmouseoccuron two

areason theMarineCorpsBase,CampPendletonandon a small parcelof landon

privatepropertyat theDanaPointHeadlands.To date,recoveryactivitiesto

achievetheprotectionandconservationofthePacific pocketmousehavebeen

recentandlimited in scope. Futureefforts will, by necessity,includehabitat

protectionand speciesmanagementaccomplishedthroughthecooperationof

Federal,State,andlocal agencies;speciesexperts;landowners;andother

interestedcitizens.

FederalActions

Section7(a)oftheAct, asamended,requiresFederalagenciesto evaluatetheir

actionswith respectto any speciesthat is proposedor listed asendangeredor

threatenedandwith respectto its critical habitat,if any is designated.Regulations

implementingthis interagencycooperationprovisionoftheAct arecodifiedat 50

CFRPart402. If a speciesis listed, section7(a)(2)requiresFederalagenciesto

ensurethat activitiestheyauthorize,fund,orcarryout arenot likely to jeopardize

thecontinuedexistenceof suchaspeciesor to destroyoradverselymodify its

critical habitat. lf aFederalactionmayaffect a listed speciesor its critical

habitat,theresponsibleFederalagencymustenterinto formalconsultationwith

us(theService)in accordancewith theregulationsat50 CFR402. Federal

agenciesthat authorize,fund,orcarryout activitiesthat mayaffectthePacific

pocketmouseincludetheService;DepartmentoftheNavy; MarineCorpsBase,

CampPendleton;theArmy Corpsof Engineers;and FederalHighways

Administration. Theseagencies,whichare all individually chargedto utilize their

resourcesto furtherthepurposesoftheEndangeredSpeciesAct, areindividually

treatedbelow:

27

1) U.S. Fish andWildlife Service: Sincethedesignationofthesubspeciesasa

candidatefor listing in 1985,wehaveattemptedto conservethesubspeciesby

seekingthesupportandcooperationofothergovernmentagenciesandthe

interestedpublic to achievethatgoal. In an openletterdatedMay 7, 1992to local

planningagenciesand concernedpartieswithin thehistoric rangeof the

subspecies,wesolicitedrelevantinformationandcommentspertainingto the

status,distribution,andthepossiblelisting of thePacificpocketmouseandeight

coastalplant species.Prior to listing the subspecies,wecoordinatedwith local

jurisdictionson specificprojectsin therangeof thePacific pocketmouseand

askedfor focusedsurveysfor thesubspeciesandtheavoidanceof impactsto

potentialhabitats.Also prior to listing, we contactedtheMarineCorpsBase,

CampPendletonnaturalresourceofficepersonnelregardingtheprecariousstatus

of thePacificpocketmouseandaskedfor their assessmentof thestatusand

distributionofthe subspeciesx~ithin theirjurisdiction.

Sincethesubspecieswaslisted, we, in accordancewith our responsibilitiesunder

theNationalEnvironmentalPolicy Act andEndangeredSpeciesAct, have

continuedto askfor focusedPacific pocketmousesurveysin appropriatehabitats

throughoutthehistoric rangeof thesubspecies.Wehavealsoconductedtwo such

surveysonourown (National Wildlife Refuge)lands. We haveauthorized,in

partnershipwith theCaliforniaDepartmentofFish andGame,projectsin

accordancewith section6 ofthe EndangeredSpeciesAct thatprovidefor the

identificationanddelineationof potentialhabitatand,hopefully,additionalextant

populations. We arealso undertakingstudieson CampPendletonto gather

informationon habitataffinities anddemographicsof thePacific pocketmouse,

and haveperformedpresence/absencesurveyson our Refugelandsin theTijuana

Estuaryarea. In addition,wehaveissuedrecoverypermitsin accordancewith

section1 0(a)(1 )(A) oftheEndangeredSpeciesAct thatallow for appropriateand

prudentPacific pocketmousesurveysandmanagement.

2) TheDepartmentoftheNavy (Navy): TheNavy is chargedwith protecting

trustresourceson multiple areasof landcontainingpotentialPacific pocketmouse

habitat. Biologistswith theNavy’s EnvironmentalPlanningandNaturalResource

ManagementDivision (SouthwestDivision) havecoordinatedandconductedfive

28

focusedsurveysfor thePacific pocketmouseon Federallands. Becauseno

Pacific pocketmice havebeendetectedduring thecourseofthesesurveys,it is

likely thatnonewill bedirectlyaffectedby impendingprojects.

3) MarineCorpsBase,CampPendleton:CampPendletonhasauthorized,

coordinated,andfundedmultiple surveysfor thePacific pocketmousein recent

years. Focusedsurveysfor thePacific pocketmousewereconductedin

appropriatehabitatsalongthecoastalportion(within 3 miles oftheshoreline)of

CampPendletonduring 1994, 1995, 1996, and 1997. Presence/absencesurveys

for thePacific pocketmousearescheduledto be completedin 1998(Buck 1997);

thesesurveyscovera majority ofthepotentialhabitaton base.

For purposesof continuedmilitary trainingandland managementactivities,the

level of surveyeffort is consideredsufficientto concludeabsenceofthePacific

pocketmouseon thosetraining areaswhereno Pacific pocketmicewerefound by

this orpreviousstudies. However,constructionprojectsin areastypical of Pacific

pocketmousehabitatmaystill requirespecific trappingsurveys,accordingto our

(Service)protocols(Ogden1997).

Surveyeffortsauthorizedby CampPendletonin 1995 ledto thediscoveryoftwo

ofthethreelocaleswith knownextantpopulationsof thePacific pocketmouse.

TheBasealso developedahabitatevaluationmodel (Spencer1997). Camp

Pendletonis funding someadditional surveyson theBase,with trappingin 1998

on EdsonRangeImpactAreaand in theStuartMesaarea(Spencer1997). The

Basehasnotedthat theywould authorizethetranslocationof animalsfrom the

Baseto off-baselocalesfor purposesof establishingnewpopulations.Camp

Pendletonpersonnelareadditionallypreparingamanagementplanfor Base

uplandhabitatsandhavebeguntheprocessof identifyingpotentialhabitatsby

developingamodel that relieson datapertainingto soils, vegetation,elevation,

and distancefrom thecoast.

4) U.S. Army Corpsof Engineers:TheU.S. Army Corpsof Engineers(Corps)

regulatesandpermitsthedischargeof fill into wetlandsandwatersoftheUnited

Statesin accordancewith variousprovisionsof section404 of theCleanWater

29

Act. Becausethe Pacific pocketmousecouldoccurin areasthataredesignatedas

wetlandsorwatersof theUnitedStates,theCorpsmayregulatesomeprojectsthat

couldaffect thesubspecies.FortheInternationalWastewaterTreatmentPlant

Projectin theTijuanaRiver Valley,theCorpsfundedsurveysfor thePacific

pocketmousewithin theactionareaoftheproject. Like any Federalagency,the

Corpsis requiredto consultwith us in accordancewith section7 of the

EndangeredSpeciesAct if theirdiscretionaryauthorityto issuepermits“may

affect” federallylisted species,including thePacific pocketmouse. Avoidanceor

compensationmeasuresaregenerallyintegratedinto projectsthatmayaffect

listed species.

5) FederalHighwaysAdministration: TheFederalHighwaysAdministrationhas

requiredandauthorizedfocusedsurveysfor Pacific pocketmice in conjunction

with theproposedFoothill (South)TransportationCorridorproject. It is expected

thattheFederalHighwaysAdministrationwill continuewith informal

consultation(ongoingasofApril 1998)and will initiate formalconsultationwith

us in accordancewith theregulationsat 50 CFR402 if theprojectmayadversely

affectthePacificpocketmousepopulation(s)nearSan MateoCreek. At the

presenttime, theprojectapplicant,theTransportationCorridorAgencies,

apparentlyis redesigningtheproposedprojectto avoiddirect impactsto the local

Pacificpocketmouseoccupiedhabitatasit wasdefinedin the lastsurveyeffort.

Theapplicant’sproposedpreferredalternativecurrentlyparallelsSanMateo

Creek. Onealternativealignmentfor theproposedprojectavoidsSanMateo

Creekdrainagealtogetherby connectingwith Interstate-Sfartherto thenorth. We

areevaluatinganumberofalternativesin coordinationwith theFederalHighways

Administration.

StateandLocal Actions

CaliforniaDepartmentofFishand Game(Department):BecausethePacific

pocketmouseis nota State-listedthreatenedor endangeredspecies,it is not

presentlyprotectedin accordancewith theCaliforniaEndangeredSpeciesAct

(CESA). However,theDepartmentformally supportedthe listing ofthis

30

subspecies(K. Berg,CaliforniaDepartmentof FishandGame,in litt., 1992)and

recognizesthePacificpocketmouseasaSpeciesof SpecialConcern.

TheCaliforniaEnvironmentalQuality Act (CEQA),enactedin 1970,providesfor

thedisclosureandmitigationof projectimpactsto State-designatedrareanimals

andplantsin accordancewith theCEQA environmentalreviewprocessconducted

by theDepartment.Therediscoveryof thePacific pocketmousein 1993wasa

resultoftheDepartment’sformal requestfor a focusedsurveyfor this subspecies

on theDanaPointHeadlands.

TheDepartmentis alsoresponsiblefor enforcingvariouscodesestablishedto

protectnativeCaliforniaplantsandanimals. In this capacity,theDepartment

couldissuecitationsfor theunauthorizedcaptureofPacific pocketmice. As

such,authorizationto trapandcollectthePacific pocketmouseis excludedfrom

standardcollectingandtrappingpermits.

Most recently,theDepartment,at therequestoftheStateofCaliforniaResources

Agency,initiatedaNaturalCommunityConservationPlanning(NCCP)program

in an attemptto conservethecoastalCaliforniagnatcatcher(Polioptila californica

californica), thatspecies’coastalsagescrubhabitat,andothersensitiveplant and

animalspeciestherein. TheNCCPplanningeffort hasdevelopedto thepoint

wherea minimumof 30 cities, 2 counties,35 landowners,and3 landmanagement

agencieshaveformally committedto developorto assistin thedevelopmentof

conservationplansthat (basedon processguidelinesfinalizedby theCalifornia

ResourcesAgencyon September1, 1992)meetthestandardsfor allowing

incidental takeof a federallylisted speciesundersection10 oftheEndangered

SpeciesAct andarein compliancewith the4(d) rule establishedfor thecoastal

Californiagnatcatcher.Landowner/landmanagementagencyenrollments,which

allow for thedestructionof 5 percentof theremainingcoastalsagescrub,

encompassabout18,200hectares(45,000acres)of coastalsagescrubhabitat.

Conservationneedsofthe Pacific pocketmouseorthesubspecies’potential

habitatarebeingaddressedby severalplansbeingdevelopedundertheNCCP

program. At thepresenttime, however,thePacific pocketmouseis not the

31

primaryfocusofanyNCCPandfew subregionalplansor individualplanshave

beencompletedor implementedthat providefor specificprotectionofthe

subspecies,with theexceptionoftheapprovedCentral/CoastalNCCPplan in

OrangeCounty. This planhasidentifiedpotentialPacific pocketmousehabitat

within theproposedconservation(reserve)area.

CaliforniaStateParks(StateParks): A branchof TheResourcesAgency,Stateof

California,this agencyleaseslandfrom theMarineCorpsBase,CampPendleton

thatcontainsasignificantportionof thenorthCampPendletonPacific pocket

mousepopulation. StateParksis responsiblefor managingtheselandsaswell as

otherparkpropertyin southernCaliforniathat apparentlycontainssuitablePacific

pocketmousehabitat. Oneof StateParks’ landmanagementmandatesis the

conservationof sensitivespeciesandtheirhabitats.Theagencyalsoparticipates

fully in NCCPplanningandconservationefforts.

City ofDanaPoint: TheCity ofDanaPoint (City) hasexpressedan interestin the

conservationofthePacificpocketmousepopulationandothersensitiveanimals

andplantswithin theirjurisdiction. In thisregard,theCity suggestedthepotential

needfor conservationmeasuresaboveand beyondthosein theOrangeCounty

Central/CoastalNCCPplan. On April 28, 1998, theDanaPointCity Council

unanimouslysupporteda developmentproposalthat callsfor 185homesand28

hectares(70 acres)ofopenspaceon the49-hectare(122-acre)DanaPoint

Headlandsparcel. Apparentlymost of this 28 hectareopenspace,which includes

the DanaPointHeadlandPacific pocketmousepopulation,would be privately

owned. It is undeterminedwhat retentionofthishabitatareaasprivateproperty

generalopenspacemeansfor theshort-and long-termconservationofthePacific

pocketmouseat this location.

32

II. Recovery

RecovervStrategy

Therecoverystrategyfor thePacificpocketmouseconsistsoftwo components.

Thefirst is to stabilizetheexistingpopulationsby protectingcurrentlyoccupied

habitat. In additionto providingprotectionto theknownpopulations,thefirst

componentalso entailssearchingfor additionalpopulations,andproviding

protectionto any that arefound. Thesecondcomponentinvolvesestablishing

additionalpopulationsthrough: 1)naturalcolonization/recolonizationintonearby

and adjacenthabitats,coupledwith habitatmanagementin theseareas,and2)

translocationand/orthereleaseof captive-bredindividuals.

Thesuccessoftranslocationsinto continental(asopposedto island)habitatsis

poor(Soule’ 1996). In thecaseofthePacific pocketmouse,thenumberof

individualsavailablefor translocationarelikely to be small,makingsuccessmore

tentative(Soule’ 1996). ExtantpopulationsofPacific pocketmice currentlymay

not be largeenoughto supportacaptivebreedingprogram;asubstantialnumber

ofindividualsprobablywill be neededto establisha successfulbreedingprogram

(Behrends1997). Releasesofwild-caughtanimalsareusuallymoresuccessful

thanreleasesof captivebredanimals,and introductionsof widespreadspeciesare

moresuccessfulthanintroductionsof specieswith limited ranges(Soule’ 1996,

Pimm 1991).

Becauseestablishingadditional populationsis experimentaland,to date,hasmet

with limited successwith otherspecies,we intendto workwith acloselyrelated

surrogatespeciesto refinecaptivebreedingandreleasetechniques.If

translocationis successfulwith a surrogatespecies,we wouldpursuesuch

techniqueswith thePacific pocketmouse. However,prior to theimplementation

ofatranslocationorcaptivebreedingprogramfor thePacific pocketmouse,

suitableunoccupiedhabitatmustbe identifiedandresearchmustbe conductedon

theprotocolsfor both thetranslocationandcaptivebreedingof P. longimembris.

Thenarrativeoutlineto follow andAppendix2 delineateprotocolsfor captive

breedingand translocationtechniquesandactivities.

33

Theimmediaterecoverygoal is to averttheextinctionof thePacific pocketmouse

by focusingon short-termstrategiesto improvethesubspecies’prospectsfor

survival. Foremostamongthesearetheimmediateprotectionandrestorationof

existingpopulationsandthehabitatof thesubspecies.Consideringtheextremely

small populationsizeof thePacific pocketmouse(fewer than 150 individual

animalswere detectedfrom 1993 to 1997)andthefragmentationanddepletionof

thecoastalstrand,river alluvium,and coastalsagescrubhabitatsuponwhichthe

subspeciesdepends,further lossesof occupiedorpotentialhabitatwould seriously

reducetheprobabilityofthepersistenceofthesubspecies.Giventhesmall sizes

of thepopulationsat thethreeknownextantlocales,theapparentsedentarynature

ofthe subspecies(Meserve1972),andtheseverefragmentationand diminutionof

thesubspecies’habitat,thePacific pocketmouseis highly susceptibleto

extinction asaresultof environmentalor demographicfactorsalone(seeMace

andLande1991).

Unless,or until sufficient,additionalviablepopulationsarediscoveredand/or

establishedand protected,it is imperativethat existingpopulationsbe protected

andexpandedthroughactive management.Lossor degradationof any of the

populationsat thethreeknownextantlocalescould irretrievablydiminishthe

likelihood of thesubspecies’survival. All knownextantpopulationsareessential,

including theDanaPoint Headlandspopulation(Boggs1997,Buck 1997,Price

1997,Silver 1997,Silver andDrumm 1996,Soule’ 1996). Concurrentwith the

initial priority ofprotection,conservation,andappropriatemanagementof

existing populations,recoveryshouldfocuson the identificationof potential

habitatandcreationofadditionalhabitatandviablepopulations.Althoughthe

fundamentalsof populationbiologyand conservationbiology (e.g.,Mace and

Lande1991)stronglysuggestthat additional(or larger)populationsofthePacific

pocketmousearecritical to reducetherisksof stochasticextinction,the biology

and life historyof thePacific pocketmousecurrentlyis not sufficiently well

knownto permit conclusiveassessmentsofviablepopulationsizeandtheamount

andconfigurationof essentialhabitat. “Essential”habitatis definedherebyto be

thoseareasnecessaryfor therecoveryofthesubspecies.

34

Accordingly,thisrecoveryplanshouldbe reviewedwithin 3 yearsofbecoming

final andevery5 yearsthereafter.However,thisdocumentshouldbe

immediatelyreviewedif, at any time, newdataand analysespertainingto the

subspecies’naturalhistory,population/metapopulationdynamics,viable

populationsizes,andmanagementmeasuresrevealthatthe subspeciesis not

responding,or is likely not to respond,to therecoverymeasuresprescribed

herein.

RecoveryObjectivesand Delisting Criteria

Theultimateobjectiveofthis recoveryplan is to protectandmaintainsufficient

populationsandhabitatof thePacific pocketmouseto allow theremovalof this

subspeciesfrom theList of EndangeredandThreatenedWildlife in accordance

with the EndangeredSpeciesAct. TherecoveryofthePacific pocketmousewill

involveatwo-stageprocess,beginningwith reclassificationofthesubspecies

from endangeredto threatenedstatus.

RecoveryofthePacificpocketmousewill likely takeapproximately25 years

(until theyear2023). WemayconsiderreclassifyingthePacific pocketmouseto

threatenedstatusif andwhen:

1. Tenpopulationsareindependentlyviable andstableor increasingandtheir

habitatsaresecure(freefrom risk ofloss)andfully protectedthroughfee

ownershipby a resourceagencyor conservationprogram,conservation

easement,or othermeansofpermanentprotection. PopulationsofPacific

pocketmice shallbe consideredviable if theappropriateanalysisofmeasured

populationparametersindicatethat eachpopulationhasa 95 percentorgreater

chanceofsurviving for 100 years.

2. Occupiedhabitatconsistsof aminimumof 2,000hectares(4,940acres)that

aresecureand fully protectedthroughfee ownershipby a resourceagencyor

conservationprogram,conservationeasement,orothermeansof permanent

protection.

35

3. All Pacific pocketmousepopulationsaremanagedthroughaprogramto

maintaingeneticdiversity for futuregenerations.

4. All Pacificpocketmousepopulationsand essentialhabitataremanagedsothat

currentandpotentialthreats(e.g.,predationanddisease)areeliminatedor

minimizedto theextentthat eachpopulationis not at risk ofextirpation.

Essentialhabitatis definedto meanthathabitatnecessaryfor thefull recovery

ofthesubspecies.

We mayconsiderdelistingthePacific pocketmouseif andwhen:

1. All actionsnecessaryfor reclassificationto threatenedhavebeenimplemented.

2. Any necessaryprotection,restoration,andenhancementactivities (on all sites

thathavebeendeterminedto be essentialto therecoveryofthesubspecies)are

successfullycompleted.

3. Populationsof thePacific pocketmousearerepresentativeof thefull (existing)

geneticvariability and historicalgeographicalrangeof thesubspeciesand

occurin habitatsthat collectivelyrepresentthefull rangeofparameters

observedand describedin thepastorduring prescribed,futureresearch,and

monitoringefforts.

In orderto delist thesubspecies,wemustalsodeterminethat thefollowing five

factorsno longercontinueto adverselyaffectthesurvivalandrecoveryofthe

subspecies:(1) thepresentor threatenedmodification,or curtailment,ofthe

subspecies’habitator range;(2) overutilizationfor commercial,recreational,

scientific, or educationalpurposes;(3) diseaseandpredation;(4) inadequacyof

existing regulatorymechanisms;and (5)otherhuman-madeornaturalfactors

affectingthecontinuedexistenceof thesubspecies(50 CER 424.11). A final

decisionrelatingto thedelistingof thesubspecieswould be madeonly aftera

thoroughreviewof all relevantinformation, includingprescribedresearch.

36

Narrative Outline for RecoveryActions

1Identify and protect all extantpopulations and essentialhabitat.

Pacificpocketmousepopulationsoccurat threesites: the DanaPoint

Headlandsin OrangeCountyandSanMateoCreek(northernCamp

Pendleton)andOscar-I (southernCampPendleton)in SanDiego County.

Fewerthan 150 individuals (with recapturesconsidered)havebeenlive-

capturedatthesesites(OGDEN 1997,U.S. FishandWildlife Service

1998). Thehistoric rangeof thePacificpocketmousehasbeenadversely

affectedby urbanandsuburbandevelopmentandthedemandfor further

coastaldevelopmentwithin its rangecanbeexpectedto continue

indefinitely. Consequently,achievingtheobjectivesoftherecoveryplan

requiresthatthe identification,selection,andprotectionofessential

habitatsandpopulationsbe doneexpeditiously.

1.1 Protect and secureextant populations.

Therecoverycriteriaindicatethat 10 viablepopulationsare

required.Lossor degradationofany ofthepopulationsatthethree

known extantlocalescouldirretrievablydiminish thelikelihoodof

thesubspecies’survival. All extantpopulationsareessential.

Thesepopulationsshouldbe protectedandsecuredfrom

significantpotentialimpacts. This shouldincludededicatingthe

biological resourceopenspacethat hasbeensecuredfor thearea

occupiedby theDanaPointHeadlandspopulationto conservation

ofthePacificpocketmousepopulationon sitein perpetuity.

1.2 Undertakesurveysto locateunknown populations.

Learningwhetheradditionalpopulationsexist is critical to

achievingthe objectivesoftherecoveryplanto theextentit

influencesthenatureandintensityof managementefforts on

populations.Thelocationof additionalpopulationsmaymake

37

intensivemanagementefforts to establishadditionalpopulations

lessimperative.

Efforts to locateany additionalpopulationsareoccurringthrough

two avenues:a) throughtheenvironmentalreviewprocessof

proposeddevelopmentprojectsrequiredundertheCalifornia

EnvironmentalQuality Act (CEQA), theNationalEnvironmental

Policy Act (NEPA), andtheEndangeredSpeciesAct, andb)

throughspecialstudiesundertakenby variousState,Federal,and

local agencies,suchastheService,theMarineCorpsBase,Camp

Pendleton,andtheCaliforniaDepartmentofParksandRecreation.

The ServiceandtheCaliforniaDepartmentofFishandGame

shouldcommunicatesurveymethodsand datareporting

requirementsto theappropriateagencies,jurisdictions,and

individuals, andadvisethemon whenandwheresurveysare

needed.

Surveysshouldbe performedin BajaCalifornia,Mexico to

determinepossibleoccupation.Currentaerialphotosand satellite

imageryof thisareashouldbe obtained,aswell asany available

soils andvegetationdata/maps.Historic samplingof muchofthis

areadid occurandtheserecordsshouldbe researchedfor cluesto

potentiallocations. CoordinationbetweenU.S. andMexican

authoritiesandexpertsshouldoccur. Cooperativeand systematic

searchesby U.S. and Mexicanmammalogistsshould be performed

in BajaCaliforniaNorte in coastallocalesbetweenthe

U.S/Mexicoborderandthecity ofEl Rosario.

1.3 Continue to refine a standardizedsurveyapproach.

We havedevelopeda standardizedsurveyapproachto helpensure

that theresultsof surveysare reliable,andcorrectlyindicate

presenceor absenceof thePacific pocketmouse. Thestandardized

surveyapproachshouldcontinueto be testedandrefinedbecause:

38

• Like mostsmall mammalpopulations,populationsofthe

Pacific pocketmouseareexpectedto showdramatic

fluctuationsin numbers. Surveyresultsin oneareashould

not be appliedto other,evenadjacent,areas. Thesurvey

protocolshouldbe sensitiveenoughto detectthe

subspecieswhennumbersarenaturallylow.

• ThePacific pocketmousemaypersistin unlikely places,

andall populationsareimportantto theconservationof this

subspecies.Small populationsin isolatedlocalesmay: a)

be importantin maintainingthegeneticandecological

diversity ofthesubspecies,b) persistin the long termif

carefullymanaged,andc) provideanimalsfor translocation

orthepossibleestablishmentof captivebreeding

populations.

1.4 Identify prospectivehabitat and population sites.

Reconnaissancesurveysareneededto identify potentialhabitat

thatis eitheroccupiedby thesubspeciesor canserveasahostsite

for translocationefforts. Becauseof thesubspecies’relianceon

sandysoils, suchefforts shouldbeginwith arange-wideanalysisof

soils andidentify thosesimilar to thosethat supportexisting

populations.Regionalplanningefforts identify andprotect

potentialand prospectivehabitatareas.

Potentialhabitatshouldbe identifiedbasedon soils maps,foot

surveysof thesite, andlive-trappingsurveys. Detailedanalysisof

theseandotherappropriatefeaturesshouldbe performedto revise

andrefinetheexistinghabitatevaluationmodeldevelopedby

CampPendleton.Potentialhabitatsitesin Los AngelesCounty

includetheEl Segundodunesadjacentto Los Angeles

InternationalAirport andselectedareasof thePalosVerdes

Peninsula.Prospectivesitesin OrangeCountyinclude(from north

39

to south)BolsaChica(uplandsaroundthewetlandsandgrasslands

to thesouth),theCentral/CoastalOrangeCountyReserve,San

JoaquinHills, UniversityofCalifornia Irvine, CrystalCoveState

Park,DanaPointHeadlands,andSan ClementeStatePark. The

largestnumberofsitesandacreageofhabitatoccursin SanDiego

County,includingSan OnofreStatePark,thecoastalportionsof

CampPendleton,BatiquitosLagoon,TorreyPinesStatePark,

BorderFieldsStatePark,andthemouthoftheTijuanaRiver.

Surveysshouldalsobe performedin andaroundthefollowing

areas:theNavalRadio ReceivingFacility (NRRF) on the Silver

Strand,Spooner’sMesa,Outlying LandingField (TijuanaRiver),

PenasquitosLagoon,SanDieguito Lagoon,SanElijo Lagoon,

AquaHediondaLagoon,andBuenaVistaLagoon.

1.5 Identify essentialhabitatsand sites.

Essentialhabitatsrequiredfor therecoveryofthePacificpocket

mouseshouldbe identifiedbasedon studiesofpopulationsize,

extentofpotentialhabitat,dynamicsof habitatoccupationand/or

succession,ecosysteminteractions,opportunitiesfor population

andhabitatmanagement,andtheresultsof researchon viable

populationsizesand metapopulationdynamics(seeSection4).

Theidentificationof essentialPacific pocketmousehabitatshould

beginimmediately.

1.6 Evaluate and prioritize protection alternatives for essentialhabitat.

Multi-speciesplanningefforts areunderwaywithin thehistoric

rangeofthePacific pocketmouse. Protectionoptionsfor habitats

includefeeownership,voluntary landownerprotectionplans,deed

restrictions,resourcemanagementplans,easementsand

memorandaofagreement.Theadequacyof theseprotection

alternativesshouldbe evaluatedwith respectto the long-term

40

viability of Pacific pocketmousepopulationsandhabitatat these

sites. Regionalplanningefforts shouldtakeinto accountoverall

ecosystemfunctions,self-sustainability,dynamicnatureofhabitat

occupationthrough time,connectivityandfragmentation,fire and

fire abatementeffects,andthe influenceof adjacentlanduses.

1.7 Protect essentialhabitats and sites.

Utilizing theprotectionalternativesconsideredandprioritized

above,essentialhabitatsandpopulationsshouldbe protectedin

perpetuity. As developmentpressureintensifies,areasofpotential

Pacific pocketmousehabitatwill likely becomemorefragmented

and isolated. Conservationandmanagementoftheseimportant

sitesis essential,butwe recognizethateventhebestsitesmay

continueto losespecies(lossof diversity)if isolatedfrom other

similar habitatpatches(Marguleset al. 1982). Researchin relation

to island biogeographyandextendedto thestudyof naturereserves

hasshownthat fragmentedhabitatswill not supporta full rangeof

species(Joneset al. 1996;HarrisandGallagher1989). To

maintaintheirfull potential,theseecosystemsasawholemustbe

managedin away which will supportandcomplementfull

ecosystemfunctioningto theextentcurrentlypossible. Occupied

habitat,potentialhabitat,andsurroundinglinkagesshouldbe

securedandprotectedsothattheecosystemuponwhichthePacific

pocketmousedependsis conserved.

2 Prepareand implement habitat managementplans.

TheconservationandmaintenanceofexistingpopulationsofthePacific

pocketmouseandits habitat,aswell assuitablehabitatathistorical

locations,areimmediaterecoveryplanpriorities. Protectingand

maintainingexistingpopulationsincludesarangeof potentialactionsand

interventions. In theshort term,it involvesprotectionagainstconversion

of occupiedhabitatandvariousdisturbancesin andaroundoccupied

41

habitatthatcouldreasonablybe expectedto adverselyaffect thePacific

pocketmousepopulation. Suchdisturbancesincludeoff-site activitiesthat

would fragmentPacific pocketmousepopulations,on-siteoff-highway

vehicleuse,excessivefoot or bicycle traffic, andpredationby catsand

otherpredators(particularlyexoticpredatorsand artificially high native

predatorlevels). In the long-term,it involvesactivelymanaginghabitatin

someareas,but providingfor self-sustainingecosystemfunctions

whereverpossibleso asto minimize therisk ofextinction andto conserve

theecosystemuponwhich thePacific pocketmousedepends.

Managementplansshouldbe preparedfor eachextantpopulationasa

meansto identify, avoid,minimize,and off-set threats,to protectand

enhanceexistingecosystems,habitatsandpopulations,andto manage

habitatto maximizepocketmousepopulationviability/size. If additional

populationsare located,site-specificmanagementgoalsandobjectives

shouldbe developed,includedin theappropriatemanagementplan,and

implemented.Conservationof theecosystemuponwhich thePacific

pocketmousedependsshouldbe the long-termgoalofall management

plans. All researchdescribedbelowshouldbe coordinatedandcombined

asappropriate.

2.1 Monitor population trends and identify potential threats and

managementneeds.

Limited populationdataarecurrentlyavailablefor thepopulations

atthethreeknownextant locales: DanaPointHeadlands;San

Mateo Creek(north andsouthsites);andOscar-i in southern

CampPendleton.Annual, long termmonitoringof these

populationsbasedon capture/recapturestudiesis essential.Studies

designedto monitor existingpopulationswill needto be carefully

designedto yield usefuldatabecauseofthesmall populationsizes

andlimited numberofpopulations(Behrends1997). Statistically

determiningsignificantfactorsthat affectpopulationviability will

be difficult. Monitoringproposalsshouldbe peerreviewedby

42

qualifiedbiostatisticiansor scientiststo ensurethatproposed

studiesclearlydefineresearchmethodsandanalyticaltechniques,

includingstatisticalanalysesthat will beemployed(Behrends

1997). Althoughthemostsignificantcurrentthreatsto thePacific

pocketmousearehabitatdestruction,fragmentation,and

depredation,all potentialthreatsshouldbemonitoredon a

continuingbasis. Potentialthreatsincludeinvasionby exoticplant

andanimalspecies,disease,recreationalactivities,andchangesin

habitat(e.g.,vegetationdensities,edaphicfactors,meso-predator

populationincreases).Oncepotentialandrealthreatsare

identified,appropriatecorrectivemeasuresshouldbeincorporated

into managementplansfor eachsite.

2.2 Develophabitat and speciesmanagementplans.

Managementplansthat directmanagementof thesubspeciesand

its habitatshouldbe preparedfor eachknownpopulation.The

managementplansmustprovidesiteandpopulation-specific

detailsandshouldconciselydescribetheactionsto be taken,

building on themenuofactionslisted below. Thehabitatand

speciesmanagementplanshouldbe ecosystemorientedandplace

site-specificefforts in thecontextof variousregionalplanning

effortssuchastheNCCP. Theplansshouldprovidedetailsof

avoidance,minimization,andmitigationmeasuresneeded,

includingissuesof habitatavoidance,indirecteffects,adjacentland

use,edgeeffects,fire, predatorretention,fragmentation,wildlife

movementcorridors,exoticspecies,habitatsecessionandcycling,

restorationneeds,self-sustainability,and preservationoflong-term

ecosystemfunctioning. All recommendationsshouldfocuson key

problems,not indicatorsor symptoms,andbe long-termif

possible.Managementplansshouldbe amendedwhenever

necessaryto incorporatenewinformationandto implementfield

proventechniques.

43

2.2.1 Developan adaptive managementplan for Federal lands on

the Marine Corps Base,Camp Pendleton.

Two of thethreelocaleswith knownextantpopulationsof the

Pacific pocketmousearefoundon theMarineCorpsBase,Camp

Pendleton,wheretrainingexercisesresultin variousforms of

landscapedisturbance.Certain formsand magnitudesof

disturbancemaybe beneficialfor thePacific pocketmouse. Many

formsofdisturbancearelikely destructiveto Pacificpocketmouse

habitatandresidentpopulations.TheBaseandServicestaff

shouldco-developmanagementandenhancementstrategiesand

impactavoidancemeasuresfor incorporationinto theBase-wide

uplandspeciesand habitatmanagementplannow in preparation.

This planshouldincorporatemonitoring,research,and

managementneedsfor all potentialPacific pocketmousesiteson

theBase. Fire managementplansandotherexistingmanagement

planson theBaseshouldbe reviewed,andupdatedif necessaryto

includeprovisionsfor avoidingandminimizing impactsto the

Pacific pocketmouse.This managementplanshould incorporate

theMarineCorpsandServiceresponsibilitiesundersection7(a) of

theAct andthemilitary missionoftheBase.

2.2.2 Developand implement adaptive managementplansfor other

localesas necessary.

Managementplans should alsobe prepared for populations and

habitatsoutsideofCampPendleton.Managementplans in these

areascanbe arequirementofthepermitting processfor proposed

developmentprojects. In thecaseof public lands(e.g., State,

County,orcity parklandsorotherpublic openspaces),theycanbe

preparedasseparatemanagementplansor incorporatedinto

resourcemanagementor multi-speciesplanningefforts.

44

2.5 Protect Pacific pocket mousehabitat from fire and fireabatementmeasuresat occupiedsites.

TheDanaPointHeadlandsand SanMateo Creekpopulationsare

locatedon theperimeterofresidentialareas,wherehuman-caused

accidentalfiresarepossible. TheOscar-ipopulationis located

within aMarineCorpsBase,CampPendletontrainingarea,where

repeatedhuman-causedfires arepossible.Habitatadjoiningthis

populationrecentlyburned. Until theeffectsofvariousfire and

fuel abatementregimesareknown,Pacific pocketmice andtheir

habitatshouldbe protectedfrom fires or fuel abatementpractices

that could impactoccupiedhabitatsandindividuals. Potentialbut

unoccupiedhabitatshouldbe protectedfrom fuelabatement

measures.

2.6 FencePacific pocket mousehabitat where necessary.

Two Pacific pocketmousepopulationsareadjacentto residential

areas,whereurbanandrecreationaluses(including unexpected

changesin thepatternandintensity)could haveadverseimpacts.

Documentedimpactshaveoccurredin Pacific pocketmouse

habitatfrom activitiesof residentsadjacentto occupiedhabitat(M.

Pavelka,pers.comm. 1997). For example,one Pacificpocket

mousepopulationhasrecentlybeensubjectedto vegetation

clearingand grounddisturbancefor creationof a bicyclemotocross

track(J. Avery, pers.obs.). Potentialimpactsinclude,but arenot

limited to, vegetationclearing/groundmanipulation,fire, fuel

abatement,dumping/littering,bicycle/off-roadvehicleuse,pets,

exotic plantand animalintroduction,trail creation,andvegetation

trampling. As yet undiscoveredpopulationsmayalsoexistnear

residentialareas,andwould likely benefitfrom fencingthat

separatesresidentialzonesfrom potentialhabitat. Fencingmay

only havelimited usefulnessin reducingsomeoftheimpactsnoted

above. Thetypeoffencingusedneedsto be consideredcarefully

45

to ensurethatimportantpredator-preyrelationshipsare maintained

(Behrends1997),includingmaintainingcoyotepresence.For

example,perchingpredatorssuchasgreathornedowls shouldnot

be encouragedby suchfencing(Price 1997). This canbe

accomplishedby using largeenoughbuffersto distancepotential

perchesfrom occupiedhabitat,or fencedesignthatminimizes

perchingbenefits. Signageon fencingmaybe appropriate.

2.7 Control depredation by houseand feral catsand other exotic

predators as needed.

Becauseof theirrelativelocations,at leasttwo ofthethreelocales

with extantPacific pocketmousepopulations(DanaPoint

Headlandsandnorth CampPendleton/SanMateoCreek)areat

significantrisk dueto predationby houseandferal cats. An

ongoingprogramthat resultsin theremovalofhouseandferal cats

from theselocations(and maintainsviablepresenceofcoyotesand

othernativepredators)is needed.CampPendletonshould

continueto discouragehousecatownershipon Base.

Supplementalfeedingof anywild animals,including feral cats,

shouldbe discouragedBasewide.Local residentsin proximity to

thepopulationsshouldbe providededucationaloutreachmaterial

on Pacific pocketmousehabitat’coastalsagescrubecologyand the

influenceof non-nativeanimalsand landusepractices(e.g.,

outdoorfeedingofanimals,trashplacement,etc.)thatmodify

predatornumbersandotherecosystemfunctions. Activities that

arecompatiblewith nativeecosystemfunctionsshouldbe outlined

andencouraged.Using ecosystemmanagement,predator

managementprogramsshouldbe developedorexistingones

modified to keepall nativepredatorsextantatviable/naturallevels

andto eliminateexoticpredators/competitorsin the long term. A

healthycoyotepopulationon CampPendletonmayhelpcontrol

theferalhousecatpopulationsthere(Spencer1997). Predator-

prey relationshipsofthePacific pocketmouseneedto be

46

maintained.Adjacentlandusespracticesthat contributeto self-

sustainingandrelativelynaturalpopulationlevelsof native

animalsshouldbe encouraged.

2.8 Control exotic plants.

Two knownPacific pocketmousepopulationsoccurin coastal

sagescrubcommunitiesthathavebeeninvadedby aggressive

exoticgrassesand forbs. Otherescapedexotic speciessuchas

hottentotfig (Carpobrotusedulis)haveinvadedportionsof the

DanaPointHeadlandssite,which is alsovulnerableto invasionby

crystaliceplant (Mesembryanthernurncrystal/mum).Pacific

pocketmice currentlydo notoccurin portionsofthesite invaded

by theseplants. Theseinvasiveplantsshouldbe removedfrom

potentialhabitatand from sitestargetedfor translocationefforts.

As coastalsagescrubis invadedby non-nativetaxa,particularly

annualgrasses,siteson sandysoils alongthecoastalterracesand

slopesacquirean understorythatmaybe too denseto provide

useablehabitat. Othernegativeeffectsarelikely. Theinvasionof

exoticplantspeciesshouldbe monitoredand effects/control

evaluatedfurther.

2.9 Monitor the successof managementefforts.

Theeffectivenessof managementplansandefforts should be

evaluatedregularly. Evaluationcriteriashouldincludepopulation

stability andtrends,areaofoccupiedhabitat,adultfecundity,and

otherfactorsfor individual sites.

3 Enhance and expandPacific pocketmousehabitat.

ManagementofPacific pocketmousehabitathasnot yetbeenattempted,

andthereis limited informationon techniquesthat canbe usedto create,

restore,enhance,orexpandPacific pocketmousehabitats. Theregulatory

47

agenciesshouldprepare,ordirectthepreparationof, a habitat

managementplancomponentthatprovidesfor optimizationofPacific

pocketmousehabitatatmanagedsites. Techniquesthat couldbe

employedincluderevegetation(with or without salvagedmaterialssuchas

topsoil)andselectivehabitatenhancement,includingexperimentingwith

fire. Small degradedareasincapableof supportingPacific pocketmouse

populationsor otherlisted speciesmayserveassourcesforplants(seeds

andtransplants)or substratematerials(particularly sandytopsoil) for

restoration/enhancementefforts. Plantandsubstratematerialsshouldbe

salvagedfrom all developmentprojectswhereappropriate.Emphasis

shouldbe placedon self-sustaining,long-term,naturalhabitat

optimizationtechniques.Simple, low-tech,andeasymethodsshouldbe

tried first with movementto morecomplexandhigh-techmethodsif

simple methodsdo not work (Behrends1997).

3.1 Selecttarget sites for actions that enhanceor expand pocket

mousehabitat.

The habitat at knownpopulationlocalitiesis surroundedby plant

communitiesthat arecandidatesfor selectivevegetation

manipulationsto expandsuitablehabitatandpocketmouse

populations.Otheractionsthatenhanceorexpandpocketmouse

habitatmaybe recommendedat othersites. Thesitesfor these

actionsshould be identifiedandprioritizedfor their importanceto

achievingtheobjectivesof therecoveryplan.

3.2 Undertakehabitatmanipulations near or adjacent to occupied

habitat to expandavailablehabitat and increasepopulationnumbers.

Opportunitiesto promoteexpansionofPacificpocketmouse

populationslikely existwhereoccupiedhabitatis surroundedby

densecoverofArtemisiascrubsandin sandyareasdevoidof

vegetation(or dominatedby certainexoticplantspecies).Where

48

existingvegetationis dense,removalof individual shrubsor

groupsofshrubscouldcreateadditionalhabitatthatmaybe

colonizedby dispersersfrom nearbyoradjoiningoccupiedhabitat.

Wheresandyareasaredevoidofvegetation,orwhereit is

dominatedby exotic species(e.g.,Mesembryani~hemum

crystal/mumor Europeangrasses)andnot utilized by thePacific

pocketmouse,exoticscontrolandrevegetationwith appropriate

nativespecies(including reintroductionofsoil microflorawhere

necessary)could alsocreate/enhancehabitatto supportpopulations

of thePacific pocketmouse. Manipulatedvegetationwould likely

requireon-goingmanagementefforts. Forexample,handclearing

or coveragereductionmayresultin rapidregrowthfollowing root

sproutingby sagescrubspecies.Consequently,thinning to prevent

closedcanopyconditionsfrom rapidlyreoccurringmaybe

required.

Anotherapproachto reducevegetativecoverwould be theuseofa

herbicidecontainingrelativelybenignglyphosates,whichcouldbe

appliedto sproutswhenPacific pocketmice areunderground.

Experimentscouldbe undertakenaway from, andpossibly

adjacentto, occupiedsitesto ascertaintheeffectivenessof this

strategyto keepareasbetweenshrubsopen,or to reduce

understorygrasses.A principalconcernoftheseeffortswould be

to ensurethatadequateseedsourcesthatprovidefood for the

Pacific pocketmousearemaintainedin occupiedhabitat.

Compactedareassuchasabandonedroadswould likely be more

attractiveto thePacific pocketmouseif theyweredecompacted

andcoveredwith severalcentimetersof sand. Sandshould

preferablycomefrom thesamegenerallocality if removable

without harmto nativehabitats(e.g.,removedfrom areasalready

legally disturbedby construction).

Techniquesthat aremore self-sustaining/long-termand ecosystem

orientedshouldbe experimentallysought. A reductionin overall

49

plant coverandunderstorycouldbe obtainedthroughreductionin

soil fertility or “anti-fertilization”, which canbe accomplishedby

addingorganicmatter(e.g., woodchips)to thesoil matrix (T. St.

John,pers.comm. 1996)orby addingcoarseinorganicmaterial

(e.g.,sandwashedoffine materials).Conversely,careshouldbe

takenwhenexperimentingwith soil properties,assoil textureand

structure(e.g.,crusts)maybe asessentialto thePacific pocket

mouseasoptimumplantcover(Spencer1997). Allopathicplant

effectsor artificial changesin soil chemistrycouldalso be utilized

to reduceplantcover. If senescentcoastalsagescrubis

unoccupiedby thePacific pocketmouse,thenearlierseralstages

maybe moreattractive. Earlierseralstagescouldbe createdby

fire (discussedbelow) or othermethods.A mosaicofpotential

habitattypesand agescouldbe createdoutsideofoccupiedhabitat

in this manner.

Somehabitatsthatwould otherwisegenerallyremainsub-optimal

for thePacific pocketmousemaybe repeatedlymanipulatedsuch

thattheywill supportthetaxon. Otherhabitatareasthatwould

typically (andlikely historically did) supportoptimalhabitatmay

be madeoccupiableby removalofsomeperturbinginfluence(such

asexotic species).Thelatterhasthegreaterpotentialfor long-term

success.

ThePacific pocketmice found in theOscar-I areaon Camp

Pendletoncurrentlyoccurin non-coastalsagescrubhabitats,

including non-nativegrasslands,anddisturbedareasdominatedby

filaree (Erodiumsp.). Anecdotalevidencesuggeststhat theareas

of densegrasslandsarenot occupied(to a level of beingdetectable

during surveys),but thesmallcoastalsagescrub,bareground,and

low densitynon-nativegrasslandpatcheswithin themoredense

grasslandsareoccupied. Whereappropriate,habitatmanipulations

that convertadjacentexoticgrasslandareasbackto coastalsage

scrubshould be attempted,particularly thoseactionsthat promote

50

essentiallyself-sustainingandlong-termhabitattrends. Pacific

pocketmice alsoexploit thefriable soils in bermscreatedduring

roadmaintancein this area. We(theService)do notadvocate

creationof additionalberms,butprotectionoftheseexistingberms

couldbe important(M. Pavelka,pers.comm. 1998).

3.3 Adaptively managePacific pocket mousehabitat andpopulations.

ConservationofPacificpocketmousepopulationsdependslargely

on theadequateandadaptivemanagementofpopulationsandtheir

habitat. Two of themostimportantissuesto be addressedateach

sitearehowto increasehabitatutilization andviability, and

removeobstacles(particularlyartificial ones)to population

expansionanddispersalbetweenpopulations.

Preparationof interim managementplansshouldpromote

managementof Pacificpocketmousehabitatsthat is flexible and

quickly respondsto needsastheyarise. Interimplansshould be

preparedfirst for knownpopulations,thenfor otherpopulationsas

theyarediscovered.Theurgencyoftheneedfor interim

managementplans(andupdatedversionsthereof)will be

influencedby thecurrentstatusand distributionofpopulations;

relativeopportunitiesfor habitatorpopulationexpansions;and

ongoingthreats,includingdevelopmentproposalsanddepredation.

Managementplans,methodsfor monitoringand determining

populationviability andthreats,andcriteriaof monitoringthe

successof managementplanactionswill beupdatedon an as-

neededbasis. If substantialchangesare recommended,theyshould

be incorporatedintoupdatedmanagementplans. Management

plansshouldseeklong-termsolutionsthatpromoteself-

sustainabilityandfull ecosystemfunctionality,thusminimizing the

needfor, andpotentialproblemsof, activemanagement.

51

TheSan Mateopopulation(s)at CampPendletonis subjectto

naturalandartificial impedimentsto periodicmovementbetween

currentlyoccupiedhabitatareas. Mostof theseimpedimentsare

temporary,dynamic,or relativelyeasyto improve. Artificial

barrierssuchasroadways,agriculture,andflood damagereduction

efforts mayneedto be removed,modified,or enhancedsothat

connectivitybetweentheSanMateonorth and southgroupsis

improved. Naturaluplandhabitats,particularly coastalsagescrub,

in thisportionof theSanMateoCreekwatershed,shouldbe

restoredand/orenhancedto improvehabitatlinkage,facilitate

movementbetweenthetwo sitesby Pacific pocketmice,allow for

population/habitatdynamics,andimproveecosystemintegrity.

SanMateoCreekwashshouldbe restoredandmaintainedin a

naturalstate;this includesrestorationof nativefloodplain

vegetationandmaintenanceofthewashareafreeofroads,

lighting, exotic vegetation,andlinear structures(suchaswalls,rip-

rap,etc.). Provisionsfor native animal(Pacific pocketmouse,

snakes,coyote,fox,bobcat,mountainlion, etc.)movementshould

be includedwithin any artificial structuresremainingin thearea,

suchasaseriesof bridgesalongChristianitosRoad. All future

actionsin this areashouldimproveecosystemfunctionandhabitat

linkage/connectivity.

3.4 Undertake habitat manipulations at sitestargetedashost sitesfor reintroduction efforts.

Habitat manipulation mayalsobe undertakenat sitestargetedto

receivetranslocatedindividuals. Suchsiteswill containsuitableor

nearlysuitablehabitatfor thePacific pocketmouse,andarelikely

to requiresomemanipulationto optimizethehabitatfor the

subspecies.Suchhabitatmanipulationswill needto be completed

prior to any translocationefforts at agivenlocality.

52

3.5 Evaiuateand monitor the successof habitat restoration efforts.

Successesand deficienciesin therestorationefforts shouldbe

identified,reported,andcorrected.Appropriatecorrective

measuresshouldbe takenif restorationefforts do notproduce

resultsconsistentwith theobjectivesandneedsidentifiedby

relevantresearch.Monitoringandrestorationeffortsmaybe

necessaryfor at least10 yearsif difficulties areencounteredin

maintaininghigh functionandvaluehabitats.

4 Conduct researchon the life history, ecology,and population biologyof the Pacific pocketmouse.

Datashouldbe collectedandanalyzedpertainingto thegeneticvariability

(seeAppendix1), populationdynamics,life histories,ecological

requirements,andviablepopulationsizesofthe listed subspecies.Such

informationshouldbe usedto guiderecoveryactionsandto construct

mathematicalmodelsthathelp in predictingthelikelihood ofthe

persistenceof thesubspeciesovertime. Careshouldbe takento not over-

extendthepopulationviablity analysisapproachby relyingsolelyon such

mathmaticalmodelsto predictpersistenceover time(Spencer1997).

Populationviability anylasisis apowerful tool ofmoderndemographic

modeling,but it mustbe usedwith caution(Price 1997). Population

viability analysisis mostusefulfor comparingtherelativemeritsof

alternativepreserveconfigurationor plans,andtherelativeeffectsof

variousparametersandmodelassumptionsor predictedmetapopulation

survivorship(Spencer1997).

Historic, potential,andoccupiedhabitatsshouldbe mappedon GIS, along

with soils, fire history, vegetation,andsenstivespeciesdata. All

associatedGIS digital datafrom CampPendleton,cities, counties,and

otherassociatedagencieswith potentialhabitatshouldbe deliveredto us

by 1999,with updatesprovidedastheydevelop. All researchshouldbe

53

coordinatedandcombinedasappropriateandpossibleto increase

effeciencyandreducecosts.

4.1 Collect basic information on the natural history of the Pacific

pocket mouse,particularly habitat relations and diet.

ThisPacific pocketmouseis knownfrom fewpopulationsandhas

not receivedadequatehistoric researchin thefield to allow aclear

understandingofmany aspectsofthesubspecies’habitsand life

history. Thesedatashouldbe collectedastheyareimportantto the

developmentof soundstrategiespertainingto thehabitat

manipulationandecosystemenhancement.

Becauseheteromyidrodentsarearelativelyecologicallyuniform

group,informationpertainingto one speciescanoftenbe applied

to otherswith only minimal additionaldatacollectionto verify that

thePacific pocketmouseadheresto patternstypical for thefamily

(Price 1997). Usingexistinginformationin this waycouldreduce

redundancyandthecostof implementingthis task. We should

encourageadditionalcommunicationwith activeheteromyid

rodentresearcherswhocouldassistin compilingrelevantexisting

informationandhelpdeterminehow it canbe used.

4.2 Researchon potential and known predator ecology.

Researchon predatorecologywithin Pacific pocketmousehabitats

shouldbe performed(Bloom 1997). Radio telemetrystudiesof

likely predatorsincluding thethreemostabundantsnakespecies

(pacific rattlesnake,gopher,king), barn owls, greathornedowls,

coyotes,fox, andbobcatsshouldbe completed.Othernocturnal

predatorsshouldalsobe considered,includinghousecats.House

catsmayprey differentially on otherspeciesof mice (e.g.Mus

musculus)whichmayindirectly effect Pacific pocketmouse

54

populations(Spencer1997). Themaingoalofthis researchis to

determinetheabundanceofpredatorswithin Pacific pocketmouse

areas,andthelevelof predationof eachspecies. If removalof

“surplus” dispersingjuvenilePacificpocketmice for translocation

is considered,knowledgeofpredationlevelsmaybe influential in

decisionson how manyanimalsto be movedin aparticularyear

(Bloom 1997). Predatorecologyand movementinformation

would also bebeneficialwhenconsideringthepotentialfor

successfulreleaseofPacificpocketmiceinto unoccupiedsites

(Bloom 1997).

4.3 EvaluateArgentine ant invasionsinto existingand potentialhabitat.

ExoticArgentineantsareinvadingcoastalsagescrubareasnear

Pacific pocketmousehabitats.Theseantscould haveadverse

director indirecteffectson Pacific pocketmousepopulationsand

othernativespecies,includingreplacementofnativeantspecies

(R. Fisher, pers. comm. 1997,Chris Nagano,pers.comm. 1998).

Potentialecosystemeffectsinclude,butarenot limited to,Pacific

pocketmousenestlingmortality, insectpopulationshifts, and

modificationofseedlingsurvival rates.Invasionof theseantsmay

be expeditedby urbanor agriculturaldevelopment,possiblyasa

resultofsupplementalwaterbeingmadeavailable. Argentineant

invasionsshouldbe monitoredand overall ecosystemeffects

evaluated.Ant controlmethods,includingbiological controland

landusechanges,shouldbe developedif necessary.

4.4 Evaluate the role offire and fire management.

Currently,very little dataareavailableto evaluatetheoverall

effectsof fire on Pacificpocketmiceortheirhabitat. Researchis

neededto developa long-termfire management,fuel management,

andlorfuel abatementprogramthat wouldprotectthe animalsand

55

theirhabitat. If theprescribedresearchrevealsthatcertainfire and

fuelabatementmeasuresarewarrantedorpreferred,suchmeasures

shouldbe implemented.

Thedesignandimplementationof warrantedor preferredfire

suppressionandmanagementandfuel abatementactivities,

includingcontrolledburns,fuel thinning,crushing,mowing,

clearing,andfire suppressionefforts,shouldbe coordinatedamong

all regulatoryandfire managementagenciesandlandownersto

ensurethedevelopmentofsite-specificPacific pocketmouse

managementplansthat specifyoptimumhabitatmanagement

practices.Thepotentialrole of fire in managingor disturbing

habitatof thePacific pocketmouseis poorly known. This question

shouldbe addressedfor eachlocality with occupiedhabitat. Any

informationobtainedon fire effectsshouldbe incorporatedinto the

individualmanagementplans.

Someareasofunoccupiedpotentialhabitatshouldbe treatedwith

acontrolledburn andevaluatedin ascientifically-based

experimentalapproachwith thegoalof determiningthepositive

andnegativeeffectsoffire. Ecosystemeffectsof fire shouldbe

evaluatedrangewideasopportunitiespresentthemselvesby

wildfire. Existing fire historydata(including GIS digital data)

shouldbe deliveredto us,and necessaryGIS mapsshouldbe

createdand maintainedfor all potentialPacificpocketmouse

habitat.Therole offire in its positive andnegativeinfluenceon the

invasionorpersistenceof variousexoticplant speciesshouldbe

evaluated.Thepotentialadvantagesanddisadvantagesof fire asa

managementtool shouldbe addressed.

4.5 Evaluatethe effectsof artificial night-time lighting.

Artificial night-timelighting maycauseproblemsfor nocturnal

rodentssuchasthePacific pocketmousethroughpotential

56

modificationofpredationrates,obscuringoflunarcycles,and/or

causingdirecthabitatavoidance.Artificial lighting/light pollution

andits influenceon Heteromyidrodents(particularly thosetaxa

closelyrelatedto thePacific pocketmouse)andoverall ecosystem

functioning,shouldbe evaluated.Predator-preyrelationshipsin

illuminatedandunilluminatedcoastalsagescrubshouldbe

researched,with thegoalof attainingempiricaldataoneffects.

Secondaryandtertiaryeffectsshouldbe examined.Illumination of

habitatby artificial light andactivity patterns/densitiesofowls,

coyotes,foxes,bobcats,housecats,snakes,androdentsshouldbe

correlatedwith lunarcyclesandotherappropriatehabitat

attributes. All experimentationwith potentialfor adverseeffects

shouldtakeplacein areasunoccupiedby thePacific pocketmouse.

4.6 Evaluate the role of pastagricultural useson habitat function.

Theeffectsofhistoric agriculturalpracticeson habitatfunction

shouldbe evaluatedin areasthat havebeenpassivelyor actively

restoredto amoderatelevel ofcoastalsagescrubfunctioning.

Preliminaryevidencesuggeststhat areaspreviouslytilled do not

supportthePacific pocketmouse,althoughtheyseemto be

appropriatehabitatotherwise(open,sandycoastalsagescrub

adjacentto existingPacific pocketmousepopulations)(Spencer

1997,OGDEN 1997). Soil characteristics,soil

microfauna/microflora,plant structure,plantdiversity(including

exotics),insectdiversity, andseedproductionshouldbe

characterizedandcomparedin occupiedhabitatandformer

agriculturalareasthatotherwiseappearsuitable. Careshouldbe

takento not misidentifyrelationshipsandcoincidences.

4.7 Developbiological control methodsfor exoticplant species.

Currentmanagementofnon-nativevegetationrequiresa

considerablecommitmentto thoroughlyremoveor kill all above-

57

andbelow-groundpartsof thetargetspeciesand follow-up in

subsequentyearsto controlany exoticsoutbreaks.Eradicationof

mostexoticspeciescurrentlyrequiresacombinationof mechanical

and chemicalcontrol.

Thedevelopmentofbiologicalcontrolof non-nativeplantspecies

throughU.S. DepartmentofAgriculture (USDA), international,

and/oruniversityprogramsshouldbe initiated. Biocontrol

programsfor someplantpestspecieshavealreadybeendeveloped,

including theuseofsix insectspeciesto control yellow-starthistle

(Centaureasp.),an exotic from southernEurope(Randall1994)

andthereleaseof Europeanbeetlesin New York Statefor

biological controlofpurpleloosestrife(Lythrumsp.), an invasive

exotic from Europe(U.S. FishandWildlife Service1997). The

USDA is currentlyproposingreleaseofTamarix-specificleaf

beetlesand mealybugsin nineareasthroughoutthesouthwestern

U.S. (USDA 1997). TheUSDA andtheInternationalInstituteof

Biological Control headquarteredin Switzerlandreportedlyhave

staffandfacilities to pefformtheinternationalresearchneededto

performthetypeof work requiredfor biological controlof invasive

exoticplantspeciesin therangeofthePacific pocketmouse(Dr.

BerndBlossey,ProfessorofBiology, Cornell University,pers.

comm. 1997). Biological controlprogramshold thepromiseof

long-term,self-sustaining,and verywide-rangingcontrolof

invasiveplant specieswith relatively limited costsor useof

chemicals,but arenotwithout thebiologicalrisksassociatedwith

releasingadditionalexoticspecies(MIot 1997,Beardsley1997,

Perlman1997).

58

4.8 Conduct researchto understandviable population sizesand

metapopulation dynamics,and constructappropriatemathematical modelsto guide managementefforts.

To predictthe likelihood ofsurvival, informationon thenumberof

offspringproduced,the life span,andthematinghabitsof this

subspeciesshouldbe collectedandevaluated.It is sometimes

possibleto estimateapopulations’chanceof survival,basedupon

anumberofassumptions.However,morereliableestimatesare

only possibleafterconductingappropriatestudies. Thefollowing

studiesshouldbe carefullycoordinatedto producethemostusable

results.

4.8.1 Determine the reproductive potential ofthe subspeciesusingLeslie matrix models.

Thesurvivalor extinctionof a population, or of an

endangeredspecies,arechanceevents(DennisandScott

1991)for whichprobabilityestimatescanbe obtained. The

Lesliematrixmodel requiresestimatesofagespecific

survivalandfecundity,roughestimatesfor whichshouldbe

usedin preliminaryanalyseswhile thepopulationstudies

neededto obtainmorereliableestimatesareconducted.

4.8.2 Determinehabitat area requirements and dispersal

distances.

After completingtheresearchprescribedabove,arealistic

estimateoftheacreageof habitatrequiredto supporta

populationofthePacific pocketmouseshouldbe

calculated. Thishabitatacreagewill likely be different for

eachpopulationandin partdependon thehabitatquality

anddegreeto whichpopulationsfluctuatenaturally.

59

Currently,virtually nothingis knownaboutdispersal

characteristicsof thePacific pocketmousesuchasthe

timing, magnitude,anddistanceofdispersal,andwhether

particularhabitator landscapefeaturesarepreferred.These

datashouldbe collectedfor thePacific pocketmouse. To

obtainthesedata,radio trackingmaybe, if logistically

feasible,thebestmethodologyavailable. If radio-tracking

is used,emphasisshouldbe to telemetera largenumberof

juveniles/subadultsin the late summerto maximizethe

potentialto trackdispersers(Spencer1997). Otherwise,

live-trappingstudiescouldbe conductedatvarying

distancesfrom thesourcepopulationofmarkedindividuals.

A standardtrappinggrid withoutdrift fencesshouldbe

utilized dueto thepotentialfor interferencewith home

ranges,foragingandsocialinteractions,andthepossibility

of thefencesattractingpredatorsto Pacific pocketmice

(Behrends1997).

4.9 Conduct researchonconservationgeneticsof the Pacific

pocket mouse.

An understanding ofthe geneticsof theknown populations ofthe

Pacificpocketmouseusingmodernmoleculartechniquesis

needed.Thegoalsof this taskareto describegeneticvariationin

naturallyoccurringpopulationsofPerognathuslongimembris

pac~ficus;assesswhetherany of thedisjunctpopulationsshow

evidenceofreductionin geneticvariation;describeany genetic

subgroupswithin thePacific pocketmouse;andintegratethe

resultsinto conservationplanningefforts for thesubspecies.

Populationswith unusuallylow variability maybe candidatesfor

interventionsto bolstergeneticvariationthroughmixing of

populations. It maybe necessaryto concentrateconservation

60

efforts on “priority” populations.Thepriority rankingof

populationsrequiresan assessmentofhow geneticvariationwithin

thespeciesis apportionedor representedandthedevelopmentof a

strategyfor maintainingthegreatestamountofgeneticvariationin

the long term. Dataon interpopulationalpatternsofgenetic

variation shouldbe usedto identify geneticallyuniquegroupsor

subgroups.

Partofthis study includesan examinationof theintrapopulational

andinterpopulationalgeneticvariation. This informationis

importantin orderto identify populationsatrisk dueto

consequencesof the lackofgeneticvariationsuchaslossof

adaptiveflexibility within changingenvironments.Protein

allozymeandmolecularevidenceshouldbe usedto calculate

Wright’s CoefficientofRelatedness,quantifyamountsof genetic

variationwithin thepopulations,andestimatehistoric levelsof

geneflow amongthepopulations. We (theService)should

encouragestandardprotocolsfor tissuecollectionandencourage

permittedtrappersto collectandsubmitsamples(Spencer1997),if

safeandappropriate.

4.10 Refine managementplans.

Basedupontheresultsofthesestudies,refinethemanagement

plansdevelopedundertask2 above.

4.11 Refinerecovery criteria.

Theresultsofthepopulationviability analysesand metapopulation

dynamicsareneededto furtherrefinethesecriteria. Fewerthan 10

populationsmaybe neededfor recoveryif theyaresufficiently

largeandhighly unlikely to be extirpated.Manymorethan 10

populationsmaybe requiredif theyaresmall, unstable,and/or

isolated.

61

5 Identify and implementmeasuresto create additional populations.

Protectionof all existing,enhanced,and any newly discoveredPacific

pocketmice populationsandhabitatmaybe insufficient to ensurerecovery

of the subspecies.In additionto implementingthehabitatmanagement

objectivesin Task#3, it maybe necessaryto removeindividualsfrom

selectedpopulationsfor thepurposeof establishingacaptivebreeding

population,or introducingwild-bredor captive-bredindividualsinto

suitablebut currentlyunoccupiedhabitat. Potentiallysuitablehabitat

apparentlyoccurswithin existingpublicly-ownedandmanagednatural

areasthat arewithin thesubspecies’historic range. Reconnaissance-level

surveysareneededto evaluatewhetherthehabitat(substrateand

vegetation)within anumberof theseareascanpotentiallysupportPacific

pocketmousepopulations.

Most occupiedPacificpocketmousehabitatpatchesarenow small and

fragmented.Although therearealimited numberofsiteswith suitableor

potentiallysuitablehabitat,theestablishmentofpopulationsin theseareas

couldcontributeto thesubspeciesrecoveryby increasingthenumberof

populationsand constituent,individual animals.

5.1 Evaluatethe feasibility of carrying out a translocation effort

for the Pacific pocket mouse.

Nielsen(1988)recommendedthat a feasibility study should

include, in part, considerationsof the: (1) reasonfor translocation;(2) statusofthewild population(s) to betranslocated;(3) ecology,

biology,andethologyof thesubspecies;(4) currentsizeand

densityofthewild population(s);(5) movementsanddistribution

of thesubspecies;(6) male:femaleratio, (7) annualrecruitment;(8)

mortality ratesandcauses;(9) healthand conditionof the

populations;(10) geneticvariability andintegrity; (11) statusof

remaininghabitat;(12) depredationratesin targetareas;(13)

62

translocationstrategy(e.g., time ofrelease,numberandsexof

animalsinvolved); (14) capturetechniqueandtechnology;(15)

numberandlocationofreleasesites;and(16)post-releasesupport

of translocatedanimals. Researchandmanagementtasks

describedaboveshouldprovideenoughinformationto determine

thefeasibility ofattemptingto translocatePacificpocketmouse

individuals.

Translocationshouldbe consideredafterthefeasibility tasksabove

areperformedand: (1)surveysindicatethat thepotential for

undiscoveredpopulationsis very low, andpreviouslydefined

conservationandmanagementmeasuresfail to producesufficient,

essentialhabitatandpopulations,(2) researchrevealsthat animals

maybesafelytranslocatedinto targethabitats,and(3) thedonor

populationcanwithstandthelossof individuals.

5.2 Developa translocation protocol for wild-reared and captive-

bred individuals.

A protocolfor translocationofwild-rearedor captive-bred

individualsshould be preparedthat addressesall phasesof the

translocationeffort, includinghostsiteselection,habitat

manipulation,animal captureandrelease,andmonitoring.

Only sitescontainingapparentlysuitable,albeitunoccupiedhabitat

areto be consideredfor translocationefforts unlessgeneticstudies

revealthatthetranslocationofindividualsfrom anotherpopulation

is necessaryto enhancegeneticvariability ofthehostpopulation,

or otherwisebenefitthe subspecies.

Theprotocolshouldconsider: a) suitabletimesof theyearfor

translocation,b) thenumberof individualsto be movedandtarget

densities,c) thenumberandtypeofartificial burrowsandfood

(seedsand leafyvegetation)to be provided,d) spacingpatternsof

63

individuals andsexes,e) theoptimum periodoftime to maintain

animalswithin artificial burrowsto allow themto become

accustomedto theunfamiliarsurroundings,and I) thegenetic

makeupoftranslocatedanimals(seeAppendices1 and 2).

5.3 Implement a translocation program.

Translocationsshouldbe limited to sitesthat werepreviously

occupiedby thePacific pocketmouseor thatcontainthe

appropriatesubstratesand habitatattributes.Translocationsto

occupiedhabitatshouldbe doneaccordingto theprescribed

protocol.

5.4 Monitor translocated populations.

Translocationefforts areto be accompaniedby long-term

monitoringofthepopulation. Monitoringcanbe accomplished

throughestablishmentoftrappingstationswherelive-trappingis

conductedat leasttwiceeachyear,onceto sampleadultsupon

theiremergencefrom their burrowsbetweenlate April and May,

oncebetweenlate July andlate Augustto sampleadultsandtheir

annualoffspring.

5.5 Developa protocol for captive breeding and implement first

using a non-listed relatedspecies.

The captivebreedingprotocolshouldfollow Haydenet al. (1966)

and Daly etal. (1984). Theprotocolshouldrequireroutineor

regularobservationsofnaturalestrouscyclesin largenumbersof

captivefemalesin orderto determinethemostfavorablemating

time, and pairingreceptivefemaleswith malesunderconditions

that minimizemortality of individuals. Pairs shouldbe observed

for 15 to 20 minutesand immediatelyseparatedif violent behavior

is observed.If thepair appearsto be compatible,theymaybe left

64

togetherfrom 3 to 4 hoursorovernight. After this, thefemale

shouldberemovedto an observationcage. Matedfemalesshould

be kept in arelativelyquietplace,away from daily disturbance,

andprovidedwith arefugium(seealsoAppendix2).

A protocolfor captivebreedingadditionallyshouldaddressthe

following issues:

• Whethercaptive-breedingefforts shouldbeundertakenin

light oftheresultsofotherrecoveryplanactionsandtrends

in populationnumbers.

• Whetherornotsuitableorpotentiallysuitablehostsites

havebeenidentifiedwithin thesubspecies’historic range.

• A captivebreedingprotocolfor thePacific pocketmouse

surrogatespecies.Theprotocolshouldcontaintheessential

tasksdiscussedandprescribedin Appendix2. Haydenet

al. (1966)successfullybredP. Iongimembrisbangsi; it

seemsreasonableto assumethat thesameor similar

protocolcanbe usedto successfullybreedP. longimembris

pac~ficus. Experienceatbreedingpocketmice shouldbe

gainedby repeatingtheir experimentswith two relatively

commontaxa,P. longimembrislongimembrisorP.

longimembrisbangsi. Efforts to breedPacificpocketmice

shouldbe undertakenaftersuccessfulresultsareobtained

working with thesesurrogatespecies.The captivebreedingfacility for thesurrogatesubspeciesshouldnotbe located

within therangeofthePacific pocketmouse. Althoughinterbreedingof subspeciesis commonin nature,mixing ofgeneticlineagesasaresultofaccidentalreleasesofanimals

shouldbe avoided.

65

• Theminimumeffectivesizeofthecaptivebreedingcolony.

To maximizetheopportunityfor successoftheeffort, the

breedingcolonyshouldstartwith the largestfeasible

numberofindividuals. Haydenetal. (1966)usedover 200

femalesin theirprogram,in partbecauseit wasknownthat

not all individualswould be reproductivelyreceptiveduring

a given,desiredtime window. Maleswill haveto be

screenedfor their “sexualinterest”(Behrends1997).

• Geneticanalysis. Theresultsof thegeneticanalysisof

existingpopulationsofthePacific pocketmouseshouldbe

evaluated,includingthesourcepopulation(s)for the

captivebreedingandtranslocationprogramsprior to the

removalofanimals. Thegeneticanalysisshouldbe

consistentwith theprotocolpresentedinAppendix 1. The

purposeof thegeneticstudy is to determinewhetherthere

are important geneticdifferencesbetweenpopulations,whetheranypopulationshavereducedgeneticvariability,

anddeterminetheminimumnumberofindividualsneeded

to capture at least 90 percent ofthe population’s genetic

variability. Theresultsof thegeneticstudywould beused

to determinewhetherit is desirablefor a captivebreeding

programto interbreedindividualsfrom two or more

localitiesto increasegeneticvariability. Small tissue

samplesshouldbe takenfrom individual animalsfor any

necessaryfuturestudies. As analternative,thereis new

technologyavailableusing fecal analysisasafar less

invasivetechniquefor extractingDNA.

5.6 Implement a captive breeding program for a related species.

Thecaptivebreedingprogramshouldbe consistentwith the

protocolpresentedin Appendix2. In particular:

66

• Individuals for thecaptivebreedingprogramshouldbe

obtainedfrom populationswhosedistributionand

abundancearewell known,andwhosepopulationis

expectedto be ableto withstandtheremovedindividuals.

Populationswith restrictedopportunitiesfor recruitment

(e.g.,populationssurroundedby unsuitablehabitat),are

likely to producemoreindividualsin averageyearsthanare

typically recruitedinto thepopulation. Thejuvenile

productionbeyondthatrequiredto maintainaviable

populationlevel couldbe removedlate in theseason(i.e.,

late September,earlyOctober)andpotentiallybe usedin

eithertranslocationorcaptivebreedingprograms.

• Individualsshouldbe kept individually in gallonjarsor

otherappropriatecontainers,containingsandandrefuge,

andfed a diet of seeds(grassandsunflower)soakedin

water solublevitamins(petvitaminsor equivalent).

Freshly cutgrassesor lettucearesuppliedeveryotherday.

Thelaboratoryconditionssuccessfullyestablishedby

Haydenetal. (1966),including temperature,relative

humidity, andlighting, shouldbe duplicatedorusedasa

basisfor thedevelopmentof aprotocolspecifically

designedto suit theneedsof thePacific pocketmouse.

• Captive-bredanimalsareto be releasedat thehostsiteas

soonasfeasible. Theoffspringproducedin captivityby

Haydenetal. (1966)werebornfrom April to July; all

individualswould beweanedby earlyAugust. Preliminary

evidenceindicatesthat youngof theyeardispersefrom

theirnatalhomerangefrom Augustto Septemberin search

of unoccupiedhabitat. Thereleaseofcaptivebredanimals

would attemptto mimic this naturalpatternto theextent

feasible. To minimize the impactof captivity on thefitness

ofcaptive-bredindividuals,juvenilesshould bereleasedin

67

family groupsassoonasis feasible,possiblyasearlyas4

weeksafterbirth.

5.7 Implement a captive breeding program for the Pacific

pocket mouse.

CaptivebreedingofPacific pocketmice for their

reintroductioninto suitableunoccupiedhabitatcould

potentiallyplay a rolein recoveryunderspecific

conditions,particularlyif it becomesinfeasibleto obtain

foundingpopulationsby regular,selectiveremovalof

individualsfrom existingpopulations.Captivebreeding

could be undertakenif necessaryto preventthe likely,

imminentextinctionof thesubspeciesor to produce

relatively largenumbersofindividualsthatare as

geneticallydiverseaspossiblefor thepurposeof

translocation.Thechainof commandand thedecision-

makingprocessshouldbe clearlyestablishedat the

beginningofany captivebreedingprogramfor thePacific

pocketmouse(Behrends1997).

6 Enhancepublic awarenessof, and appreciation for, the Pacific pocketmouserecoveryprogram through educationaland interpretive

programs.

Publicawarenessofrestorationandotherrecoveryefforts will createa

positiveimageof theseefforts andhelpto reduceimpactsto protected

populations. Interpretiveexhibitsshouldbe establishedadjacentto

habitatscontainingPacific pocketmousepopulations.Outreachand

educationefforts will enhancethepublic’s understandingand appreciation

of theserareanimalsandpotentially reduceaccidentalimpactsto the

subspecies.Interpretivesignsandexhibitsshoulddescribeand depict

sensitivelocal resourcesandtheinvolvementandcontributionsof

volunteers;announcetheavailability ofpublishedmaterialsand

68

information;andadvertisethelocationsandtimes of interpretivewalks

andprograms. Mailings/flyersto residentsliving nearPacificpocket

mousehabitatshouldbedevelopedoutlining ecosystemandlife history

details,aswell asrecommendationsfor petcare,trashplacement,fire and

fuel abatementprecautions,hiking andbicycleuse,etc. Careshould be

takento not induceor direct vandalism.

6.1 Federal and Stateagenciesshould work with private parties to

developparticipation plans to implement specificrecovery

tasks.

ThesuccessofPacific pocketmouserecoveryefforts will depend

on cooperationamongFederal,State,andlocal agencies,

researchers,conservationorganizations,thepublic, andland

ownersto managelandscontainingPacificpocketmousehabitat

for theprotectionof thesubspecies.To furthersuchcooperation,

outreachefforts thatencouragelandownersto conservePacific

pocketmousehabitatandpopulationsshouldbe undertaken.

Theagenciesandorganizationsthat canbe expectedto cooperate

in recoveryplanningefforts arethe Service,theMarineCorps

Base,CampPendleton,DepartmentoftheNavy,California

Departmentof FishandGame,CaliforniaStateParks,theNature

ReserveofOrangeCounty,theOrangeCountyEnvironmental

ManagementAgency(throughits role asleadagencyin theCentral

andCoastalNCCPprogram),theTransportationCorridorAgencies,theDanaPoint Headlandslandowners,andtheCity of

DanaPoint (throughits jurisdictionover landuseplanningfor the

DanaPointHeadlands).In addition,thefollowing organizations

andagenciesmaybe involved in plan implementation:

DepartmentoftheNavy’, Army CorpsofEngineers,Federal

HighwayAdministration,TransportationCorridorAgencies,City

ofSanClemente,andtheEndangeredHabitatsLeague. Thelist of

69

cooperatingagencieswill be finalizedin thefirst stageofrecovery

planimplementation.

6.2 Distribute information on recovery plan actions and results to

appropriate agencies,jurisdictions, landowners, landmanagers,and the interestedpublic.

Thesupportand involvementof local jurisdictions,landowners,

thepublic, andStateagenciesareimportantwhereoccupiedand

suitablehabitatsoccur. Updatedinformationon potentialhabitats,

resultsof therecoveryplanefforts,and suggestedmitigation

guidelinesand protectionalternativesshouldbe provided

periodicallyto appropriatecity andcountyplanningdepartments.

An importantelementof this cooperationis to interfacewith the

NCCPeffort. In addition,a concertedeffort mustbe madeto

coordinaterecoveryactivitieswith interestedlandowners,land

managers,scientistswith relevantexpertise,andinterestedcitizens

andcitizens’groups.

6.3 Integrate implementation of the recovery plan with local

agencies,including appropriate NCCP lead agencies.

Thehistoric rangeof thePacific pocketmouseoverlapswith three

existingprogramsbeing implementedundertheNCCPprogram:

theMultiple SpeciesandMultiple HabitatConservationPlansin

SanDiegoCountyandtheCentralandCoastalConservationPlan

in OrangeCounty. TheServiceandCaliforniaDepartmentofFish

and Gameshouldwork with theappropriateagenciesto optimize

theopportunityfor theNCCPto affect theconservationof the

Pacific pocketmouse. Long-termself-sustainabilityand

ecosystemfunctionality of existingandpotentiallyoccupiedsites

shouldbe consideredin landuseplanningof adjacentareas,aswell

asthesitesthemselves.

70

III. Implementation Schedule

TheImplementationSchedulethatfollows outlinesthespecifiedactionsand

estimatedcostsfor therecoveryofthePacific pocketmouse. It is a guidefor

meetingtheobjectivesdiscussedin the“Recovery” sectionof thisplan and

depictstasknumbers,descriptions,priorities,anddurations;responsibleagencies;

andestimatedcosts. Theimplementationscheduleutilizes thenumberingsystem

from thenarrativeoutline in theRecoverysectionofthis documentto identify

recoveryactions.Theseactions,whenaccomplished,shouldbringaboutthe

recoveryofthePacificpocketmouseandtheprotectionof its habitat. Because

themonetaryneedsfor all partiesinvolved in recoveryareidentified,this

schedulereflectsthetotal estimatedfinancialrequirementsfor therecoveryofthe

subspecies.All costsrelatedto recoveryefforts exceptthoseassociatedwith

possibleperpetualmaintenanceof optimumhabitatandpopulations,possible

regulatoryneedsbeyondtheyear2005,possiblelandacquisition,andpossible

monitoringof restoredsitesbeyondtheyear2005areestimatedand includedin

theschedule.Thepotentialfor theseadditionalcosts,which remainto be

determined(TBD), aredisclosedin thecommentssectionofthe implementation

schedule.

Priority numbersgivenin Column I ofthe implementationschedulearedefined

asfollows:

Priority 1 An actionthat mustbe takento preventextinctionor to preventthe

subspeciesfrom decliningirreversibly.

Priority 2 An actionthat mustbe takento preventasignificantdeclinein the

subspeciespopulationorhabitatquality, orsomeothersignificant

negativeimpactshortofextinction.

Priority 3 All otheractionsnecessaryto providefor full recoveryofthe

subspecies.

71

Acronymsused:

COE

CORNELL

CSP

DFG

FWS

IIBC

LAWA

MCBCP

NROC

OCEMA

SWDIV

TBD

TCA

USDA

— U.S. Army CorpsofEngineers;

— Cornell University;

— CaliforniaStateParks;

— CaliforniaDepartmentof FishandGame;

—U.S. FishandWildlife Service;

— InternationalInstituteofBiological Control;

— Los AngelesWorld Airports;

— MarineCorpsBase,CampPendleton

— NatureReserveof OrangeCounty;

— OrangeCounty EnvironmentalManagementAgency;

— DepartmentoftheNavy,SouthwestDivision

= to be determined;

— TransportationCorridorAgencies

— U.S. DepartmentofAgriculture

72

Table 2. Implementation Schedulefor Pacific PocketMouse Recovery

Undertakesurveysto locate

inknownpopulations

10 FWSDFG

MCBCP

SWDIV

LAWA TCA

400 40 40 40

140 40 Potential

additionalcosts

eyondagency

~Osts.TBD

Priority Task TaskDescription Task ResponsibleEstimated

Costs $1,OOOs— — — —

FY FY FY FY FY Comments

Duration Agencies Total Cost 01 02 03 04 05

1

1

I

II

(Years)—

5

($l,OOOs)— — —— —

Protectandsecureextant All TBD I7BD

populations.

1.3 continueto refinea

standardizedsurvey

approach

I FWS 5 5

11.4 [dentif~iprospectivehabitat

andpopulationsites

10 EWSCSP

DFG

NROC

MCBCP

SWDIV TCA

LAWA

60 10 10 5 5 5

11.5 Identify essentialhabitats

andsites

10 All 20 2 2 2 2 2

1 1.2

Costs $l,OOOs

‘TIY____

—4

Task Description

Evaluateandprioritize

rotectionalternativesfor

ssentialhabitat

Priority

ft

11.6

Task

ft—____

Task

(Years)Duration

10

Responsible

Agencies

All

Estimated

($1,OOOs)Total Cost

26

FY

01

5

5

55

FY

04

—3

FY

05

-2

Comments

1.7 rotectessentialhabitat 25+ All TBD Extentof essential

abitatand

ossiblecosts

resentlyunknown

12.1 onitorpopulationtrends

d identify potentialthreats

nd managementneeds

25 FWSCSP

DFG MCBCP

SWDIV

2,000 80 80 80 80 80

12.2.1 evelopandimplement

daptivemanagementplan

for CampPendleton

25 MCBCP 300 20 20 20 20 20

12.2.2 evelopandimplement

daptivemanagementplans

for otherlocales

25 FWSDFG

LAWA

SWDIV CSP

TCA

142 22 27 27 26 20 Implementation

ostsare presently

nknown

12.3 rotecthabitatfrom fire and

fire abatementmeasures

25 All TBD BD

Priorityft

Taskft

Task Description TaskDuration

(Years)

ResponsibleAgencies

EstimatedTotal Cost

($1,OOOs)—

TBD

Costs $1 ,OOOs

— — —I.—FY FY FYI FY FY01 02 03 04 05

— — ——

Comments

1

1

2

2.4 encePacificpocketmouse

abitatwherenecessary

3 FWSCSP

DFG

MCBCP

SWDIV

LAWA

1 2.5 ontroldepredationby cats

nd otherexotic predators

25+ FWSCSP

DFG MCBCP

SWDIV

252 12 10 10 10 10 ontrol tobe

chievedper

integratedpredator

anagementplans

fter 2001

2 2.6 ontrolexoticplants 25 All 140 5 10 10 10 5 ossible,future

ostsTBD

2 2.7 onitorsuccessof

anagementefforts

22 FWSCSP

DFG MCBCP

SWDIV

66 3 3

—ILI~

Priority

ft

Task

ft

TaskDescription Task

Duration

(Years)

Responsible

Agencies

FWSCSPDFG MCBCP

SWDIV

LAWA

TCA

Estimated

Total Cost

($1,OOOs)

13

Costs $l,OOOs—

FY FY FY FY j FY

01 02 03 04 05

- — -1 1 1 2 2

Comments

23

3.1 Selecttargetsites foractionshatenhanceor expand

abitat

8

2 3.2 ndertakehabitat

anipulationsto increase

opulationnumbers

24 FWSCSP

DEG MCBCP

SWDIV

LAWA

360 15 15 15 15

2 3.3 daptively managePacific

ocketmousehabitatand

opulations.

25 All 265 20 20 60 60

2 3.4 ndertakehabitat

anipulationsfor

eintroductionefforts

TBD FWS DFG

MCBCP

SWDIV

LAWA

TBD ostsandtask

urationTBD

Priority

2

Task

ft

—

3.5

TaskDescription Task

Duration

(Years)

valuateand monitor 20

ResponsibleEstimated

Agencies Total Cost

($1 ,OOOs)

FWS CSP 60

Costs $1,OOOs— — I —.

FY FY FY FY FY

01 02 03 04 05

I— — — —

Comments

successof habitatrestoratio DFG

iforts MCBCP

SWDIV

LAWA

2 4.1 ollect basicinformationon 3 FWS DFG 20 10 5 5

aturalhistory MCBCP

SWDIV

2 4.2 Researchpredatorecology 4 FWS CSP 50

DFG MCBCP

20 10 10 10

SWDIV

2 4.3 valuateArgentineant 5

invasionsinto existingand

otentialhabitat

All 65 15 15 15 10

2 4.4 valuateroleoffireandfire 25 All 104 10 10 11 4 4 otential

anagement dditional costs

BD

Priority

ft

Task

ft

TaskDescription Task

Duration

(Years)

Responsible

Agencies

Estimated

Total Cost

($1,OOOs)

Costs $1 ,OOOs

— — —1—I

FY j FY FY FY FY

01 02 03 04 05

Comments

2

4

4.5 valuateeffectsof night-

ime lighting

3 FWSCSP

DFG

MCBCP

SWDIV

45

— 1

15

1

15 15

—

2 4.6 valuateeffectsof past

gricultureon habitat

function

2 FWSCSP

DFG

MCBCP

SWDIV

16 8 8

2 4.7 evelopbiocontrol methods

for exoticplantspecies

15 FWS USDA

CORNELL

500 100 100 100 100 otential

dditionalcost

BD

2

4.8.1 eterminereproductive

otentialof the subspecies

4 FWSDFG 95 20 30 25 20

2 4.8.2 eterminehabitatarea

equirementsanddispersal

istances

4 FWS DFG 85 30 20 20 15

2 4.9 onductresearchon

onservationgenetics

3 FWS 45 15 15 15

—I00

Priority

ft

Task TaskDescription Task

Duration

(Years)

Responsible

Agencies

Estimated

TotalCost

($1,OOOs)—

20

Costs $1,OOOs— 7 — — 1 — —FYI FY FYI FY FY

01 02 03 04 05

——— —10

Comments

2

2

4

4.10 efinemanagementplans 10 FWSCSP

DFG

MCBCP

SWDIV

—

2 4.11 efine recoverycriteria 4± FWS 8 2

2 5.1 valuatefeasibility of

arryingout translocation

fforts

6 FWS DFG

MCBCP

SWDIV

LAWA

24 8 8 8

2 5.2 evelopatranslocation

rotocol for wild-rearedand

aptive-bredindividuals

1 FWSDFG 6 6

2 5.3 Implementa translocation

rogram

10 FWSDFG

LAWA

750 75 75 75 o be undertaken

nly if feasiblean

ecessary(aseterminedby

rescribed

esearch);possible

futurecostsTBD

Priority

ft

—2

Task

ft

5 4

Task Description Task

Duration

(Years)

20

Responsible

Agencies

FWS CSP

Estimated

Total Cost

($1 ,OOOs)

—100

Costs $1,OOOs—! 7—

FY j FY FY FY FY

01 j 02 03 04 05

— — —

Comments

onitortranslocatedopulations DFG

MCBCP

SWDIV

2

2

2

5.5

5.6

5.7

evelopaprotocolfor

aptivebreeding(if

ecessary)

mplementa captive

reedingprogramfor a

elatedspecies

Implementa captive

reedingprogramfor

acific pocketmouse

4

LAWA TCA

FWSDFG 16

500

700

4 4 4 4

o bedoneonly as

lastresort;

ossiblefuture

ostsTBD

o bedoneonly as

lastresort;

ossiblefuture

2

20

FWS DFG

TCA

FWS DFG

TCA

2 6.1 evelopparticipationplans

o implementrecovery

25 ALL 100 4 4 4 4 4

ostsTBD

00

Priority

ft

Task

ft

TaskDescription Task

Duration

(Years)

Responsible

Agencies

Estimated

Total Cost

($1,OOOs)

Costs $1,000s

FYI FY j FY FYI FY

01 02 03 04 05

Comments

2 6.2 istribute informationon

ecoveryplan actionsand

esults

25 ALL 55 4 4 3 2 2

2 6.3 Integrateimplementationof

ecoveryplanwith local

gencies,includingNCCP

8 ALL 56 7 7 7 7 7

00

IV. References

Akcakaya,H.R. andL.R. Ginzburg. 1991. Ecologicalrisk analysisfor singleand

multiple populations. Pp.73-87 in: A. SeitzandV. Loeschcke(eds.),

SpeciesConservation:a Population-BiologicalApproach. Birkhauser

verlag,Boston.281 pp.

Avery, Jon. 1996. U.S.FishandWildlife ServiceBiologist. Personalobservation.

Bailey, V. 1939. Thesolitary livesoftwo little pocketmice. J. Mammal. 20:325-

328.

Bartholomew,G.A. andT.J. Cade. 1957. Temperatureregulation,hibernation,and

estivationin the little pocketmouse,Perognathusiongimembris.J.Mammal. 38: 60-72.

Beardsley,T. 1997. NewsandAnalysis,PestManagement:Biocontrol

noncontrol. Scientific American. November.

Behrends,P.R. 1997. Letterto U.S. FishandWildlife Serviceregarding

commentson theDraft RecoveryPlanfor thePacific PocketMouse.

November13.

Beyers,J. andW. Wirtz II. 1996. Postfire studiesin CSS;responseto small

vertebratesto vegetationchanges.In: Researchand LandManagement

Conference;SanDiego Zoo. September12-13.

Bloom, P.H. 1997. Letterto theU.S. Fishand Wildlife Serviceregarding

commentson the Draft RecoveryPlanfor thePacific PocketMouse.

November13.

Blossey,Bernd. 1997. Professor,Cornell University. Personalcommunication

82

Boggs,J. 1997. Letterto U.S. FishandWildlife Serviceregardingcommentson

theDraft RecoveryPlanfor thePacific PocketMouse. November14.

Bolger,D.,A. Alberts,R. Sauvajot,P. Potenza,C. McCalvin, D. Tran,S. Mazzoni,

andM.E. Soule’. 1994. Nativechaparralrodentspeciesdiversityin habitat

fragments: islandandedgeeffect. Inpress.

Bond, S.I. 1977. An annotatedlist ofthemammalsofSanDiegoCounty,

California. TransactionsoftheSanDiego SocietyofNaturalHistory

18(14): 229-248.

Brown,J.H. andG.A. Lieberman. 1973. Resourceutilization andcoexistenceof

seed-eatingdesertrodentsin sanddunehabitats.Ecology54: 788-797.

Brown, J.H. andZ. Zeng. 1989. Comparativepopulationecologyof elevenspecies

ofrodentsin theChihuahuanDesert. Ecology70: 1507-1525.

Brylski, P. 1993. A focusedsurveyfor thePacific pocketmouse(Perognathus

longimembrispac~ficus)on theDanaPointHeadlands,OrangeCounty,

California. Preparedfor EDAW, Inc. by thePlanningCenter,Newport

Beach,California. August,1993.

Buck, 5. 1997. Letter to U.S. FishandWildlife Serviceregardingcommentson

theDraft RecoveryPlanfor thePacific PocketMouse. November26.

Burkett, E.E. andJ.C.Lewis. 1992. Thespreadof thered fox. OutdoorCalifornia

(March-April): 1-4. Stateof California,TheResourcesAgency,

DepartmentofFishand Game.

Burt, W.H. andR.P. Grossenheider.1976. A Field Guideto theMammals. Third

edition,HoughtonMifflin Company,BostonMass. 289 pp.

Chew,R. and B. Butterworth. 1964. Ecologyofrodentsin IndianCove(Mojave

83

Desert),JoshuaTreeNationalMonument,California. J.Mammal45: 203-

225.

Chew,R.M. andA. Chew. 1970. Energyrelationshipsofthemammalsofadesert

shrub(Larrea tridentata)community. EcologicalMonographs,40:1-21.

Daly, M., M.I. Wilson, andP.R. Behrends.1984. Breedingof captivekangaroo

rats, D. merriaini andD. microps. J. Mammal. 65: 338-341.

Davenport,Arthur. 1998. U.S. FishandWildlife Biologist. Personal

communication.

Dennis,B. andJ.M. Scott. 1991. Estimationof growthandextinctionparameters

for endangeredspecies.EcologicalMonographs61(2): 115-143.

Dodd,C.K. Jr andR.A. Siegel. 1991. Relocation,repatriation,andtranslocationof

amphibiansandreptiles: Are theyconservationstrategiesthat work?

Herpetologica47, 336-357.

EDAW. 1993. DanaPointHeadlandsSpecificPlanDraft EnvironmentalImpact

Report. Preparedfor theCity ofDanaPoint,Californiaby EDAW, Inc.,

Irvine, California. StateClearingHouseNumber92021037.

Ehrlich, P. andA. Ehrlich. 1981. Extinction. TheCausesandConsequencesofthe

DisappearancesofSpecies.RandomHouse,New York. 305 pp.

Erickson,R.A. 1993. Pacific pocketmouse(Perognathuslongimembris

pac~ficus). Draft manuscriptto be includedin EndangeredRodentsof the

World, to be publishedby theSpeciesSurvivalCommissionofthe

InternationalUnion for theConservationofNatureandNaturalResources

(IUCN).

Erickson,R.A. 1994. Note to File: Pacific pocketmouseat Los Penasquitos

Lagoon: aconversationwith Dr. Phillip H. Kruttsch. October24.

84

Erickson,R.A. 1998. Letter to U.S. Fishand Wildlife Serviceregardingcomments

on the Draft RecoveryPlanfor the PacificPocketMouse. December2.

Fisher,Robert. 1997. ProjectScientist,Universityof California,SanDiego.

Personalcommunication.

Fisher,R. 1998. ConservationScientist,SanDiego StateUniversity. Personal

communication.

Frank,P.A. 1993. Conservationandecologyof theAnastasiaIslandbeachmouse.

EndangeredSpeciesUpdate9(12): 9.

Franklin,I.R. 1980. Evolutionarychangesin smallpopulations.Pp. 135-149in:

M.E. Soule’ andB.A. Wilcox (eds.),ConservationBiology: An

evolutionary-ecologicalperspective.SinauerAssoc.,Sunderland,Mass.

George,W.G. 1974. Domesticcatsaspredatorsandfactorsin winter shortagesof

raptorprey. TheWilson Bulletin 86(4): 384-396.

Gilpin, M. andI. Hanski(eds.). 1991. Metapopulationdynamics: Empirical and

theoreticalinvestigations.Biol. J. Linn. Soc. 42:1-336.

Gilpin, M. E. And M. E. Soule’. 1986. Minimum viablepopulations:Theprocess

of speciesextinctions. Pp. 13-34 in: M. E. Soule’ (ed.), Conservation

Biology: Thescienceof scarcityanddiversity. SinauerAssociates,

Sunderland,Massachusetts.

Griffith, B., J.M. Scott,J.W.Carpenter,andC. Reed. 1989. Translocationasa

speciesconservationtool: statusand strategy.Science245: 477-480.

Grinnell,J. 1933. Reviewof therecentmammalfaunaofCalifornia. University

of CaliforniaPublicationsin Zoology40: 71-234.

85

Hall, E. R. 1981. TheMammalsofNorth America. Secondedition. JohnWileyand Sons,New York.

Hall, E. R. 1946. MammalsofNevada.Universityof CaliforniaPress. Berkeley.

710 pp.

Harris,L.D. andP.B.Gallagher. 1989. Newinitiatives for wildlife conservation:

theneedfor movementcorridors. Pp. 11-34in: Preservingcommunities

andcorridors. Defendersof Wildlife, WashingtonD.C.

Harrison,5. 1991. Local extinction in ametapopulationcontext: An empirical

evaluation.Biol. J. Linn. Soc. 42:73-88.

Hansen,R.M. etal. no date. Themicrohistologicalanalysesof fecesasan

estimatorofherbivoredietary. AAFAB CompositionLaboratory,Inc., 622

‘/2 Whedbee,FortCollins,Colorado80524(telephone970-484-5749).6 pp.

Hayden,P.,J.J. Gambino,andR.G. Lindberg. 1966. Laboratorybreedingofthe

little pocketmouse,Perognathuslongirnembris. J. Mammal. 47: 412-423.

Hedrick,P.W. andP.S.Miller 1992. Conservationgenetics:techniquesand

fundamentals.Ecol.Appl. 2:30-46.

Holler,N.R.,D.W. Mason,R.M. Dawson,T. Simons,andM.C. Wooten. 1989.

Reestablishmentof thePerdidoKey BeachMouse(Perornyscuspolionotus

trissyllepsis)on Gulf IslandsNationalSeashore.ConservationBiology

3(4): 397-404.

Hubbs,E.L. 1951. Foodhabitsof feralhousecatsin theSacramentoValley.

CaliforniaFishandGame37: 177-189.

Huey,L.M. 1939a. Thesilky pocketmiceof southernCaliforniaandnorthern

Lower California,Mexico,with thedescriptionofanewrace. Transactions

oftheSanDiego SocietyofNaturalHistory 9: 47-54.

86

Huey,L.M. 1939b. Longevitynoteson captivePerognathus.J. Mammal. 40:

4 12-415.

Ingles,L. G. 1965. MammalsofthePacific States. StanfordUniversityPress,

Stanford,California. 506 pp.

James,Bob. 1998. U.S. FishandWildlife Biologist. Personalcommunication.

Jameson,E.W. andH.J. Peeters. 1988. CaliforniaMammals. Universityof

CaliforniaPress,Berkeley. 403 pp.

Jones,G.,L. Batten,and C. Bradley. 1996. Naturalareasandprime biodiversity

areas:opportunitiesfor ecologicalrestorationin England.Pp.4 1-47in:

D.L. Petersonand C.V. Klimas (eds.),Therole ofrestorationin ecosystem

management.Societyfor EcologicalRestoration,Madison,WI.

Kenagy,G.J. 1973. Daily andseasonalpatternsof activity andenergeticsin a

heteromyidrodentcommunity. Ecology54: 1201-1219.

Kenagy,G.J. 1976. Theperiodicityanddaily activity andits seasonalchangesin

free-rangingandcaptivekangaroorats. Oecologia24:105-140.

Kozakiewicz,M. andJ. Szacki. 1995. Movementsof smallmammalsin a

landscape:patchrestrictionornomadism?In.~ W.Z. Lidicker (ed.),

LandscapeApproachesin MammalianEcologyand Conservation.Univ.

MinnesotaPress,Minneapolis. 204 pp.

Lamb,T., J.C.Avise, andJ.W.Gibbons. 1989. Phylogeographicpatternsin

mitochondrialDNA ofthedeserttortoise(Xerobatesagassizi),and

evolutionaryrelationshipsamongNorth Americangophertortoises.

Evolution43(l):76-87.

Lande,R. 1995. Mutation andconservation.Cons.Biol. 9: 782-791.

87

Lande,R. andG.F. Barrowclough. 1987. Effectivepopulationsize,genetic

variationandtheirusein populationmanagement.Pp.87-123in: M. E.

Soule’ (ed.), Viablepopulationsfor conservation.CambridgeUniversity

Press,Cambridge,England.

Lewis, J.C.,K.L. Sallee,andR.T. Golightly. 1993. Introducedred fox in

California. StateofCalifornia,theResourcesAgency. DepartmentofFish

andGameNongameBird and MammalSectionReport93-10. 70 pp.

Lidicker, W.Z. (ed.). 1995. Landscapeapproachesin mammalianecologyand

conservation.Univ. MinnesotaPress,Minneapolis. 204 pp.

M’Closkey, R.T. 1972. Temporalchangesin populationsandspeciesdiversity in a

Californiarodentcommunity. J. Mammal. 53: 657-676.

Mace,G.M. andR. Lande. 1991. Assessingextinctionthreats: towarda

reevaluationofIUCN threatenedspeciescategories.ConservationBiology

5(2): 148-157.

Margules,C., A.J. Higgs,andR.W. Rafe. 1982. Modernbiogeographictheory:

arethereany lessonsfor naturereservedesign?biological Conservation24:

115-128.

MBA (MichealBrandmanandAssociates). 1997. Resultsof FocusedSurveysfor

thePacificPocketMouseFoothill TransportationCorridor - South.

Unpublishedreportpreparedfor Foothill/EasternTransportationCorridor

Agency.

MBA and LSA (MichealBrandmanandAssociates,Inc.; LSA Associates,Inc.)

1996. Resultsof focusedsurveysfor thePacific pocketmouse,Foothill

TransportationCorridor-South.Unpublishedreportpreparedfor

Foothill/EasternTransportationCorridorAgency.

88

Mearns,E.A. 1898. Descriptionsof threenewformsofpocketmice from the

Mexicanborderof theUnitedStates.Bulletin of theAmericanMuseumof

NaturalHistory 10: 299-302.

Meserve,P.L. 1972. Resourceandhabitatutilizationby rodentsofthecoastalsage

scrubcommunity. UnpublishedPh.D. dissertation,Univ. Cal. Irvine. 248

pp.

Meserve,P.L. 1976a. Foodrelationshipsofa rodentfaunain a Californiacoastal

sagescrubcommunity. J. Mammal. 57: 300-302.

Meserve,P.L. 1 976b. Habitatandresourceutilization by rodentsof a California

coastalsagescrubcommunity. JournalofAnimal Ecology46: 647-666.

Minnich, Richard. 1996. Professor,Universityof Riverside. Personal

communication.

Mlot, C. 1997. Sciencenewsoftheweek: Biological pestcontrolharmsnatives.

ScienceNews, vol. 152. August 16.

Montgomery,S.J. 1995. Resultsof a Live-TrappingSurveyandHabitat

Assessmentfor theFederallyEndangeredPacific PocketMouse

(Perognathuslongimembrispacaicus)attheTijuanaRiver Valley Regional

ParkBall FieldsSiteandSurroundingLandsin theTijuanaRiverValley,

SanDiego County,California. Draft reportpreparedfor theCountyof San

Diego,Departmentof Parksand Recreation;22 July 1995. SJM Biological

Consultants,SanDiegoCalifornia. 24 pp.

Moritz, C., C.J. Schneider,andD.B. Wake. 1992. Evolutionaryrelationships

within theEnsatinaescholtziicomplexconfirm thering species

interpretation.Syst.Biol. 41(3): 273-291.

89

Mudie, P.J.,B. Browning, and J.W.Speth. 1976. TheNaturalResourcesofSan

Dieguito andBatiquitosLagoon. Stateof California,Departmentof Fish

andGame. CoastalWetlandsSeries# 12.

Muhlenberg,M., T. Hovestadt,andJ. Roser. 1991. Are thereminimal areasfor

animalpopulations?Pp. 227-264in: A. SeitzandV. Loeschcke(eds.),

SpeciesConservation:aPopulation-BiologicalApproach. Birkhauser

verlag,Boston.281 pp.

Nagano,Chris. 1998. U.S. FishandWildlife Biologist. Personalcommunication.

Nielsen,L. 1988. Definitions, considerations,andguidelinesfor translocationof

wild animals. Pp. 12-51 in: Translocationof Wild Animals, L. Nielsenand

R.D. Brown,eds. WisconsinHumaneSociety,Inc. andtheCaesarKleberg

Wildlife ResearchInstitute,Milwaukee,WisconsinandKingsville, Texas;

333 pp.

Noss,R.F.andA.Y. Cooperrider. 1994. SavingNature’sLegacy:Protectingand

RestoringBiodiversity. IslandPress,Washington,D. C. 416 pp.

Oberbauer,T.A. andJ.M. Vanderwier. 1991. Thevegetationandgeologic

substrateassociationandits effect on developmentin southernCalifornia.

Pp. 203-212 in: EnvironmentalPerils,SanDiegoRegion(P.L. Abbott and

W.J.Elliott, eds.). SanDiego Associationof Geologists.

OgdenEnvironmentalandEnergyServicesCompany,Inc. (OGDEN) 1997.

Pacificpocketmousesurvey,PhaseIII, MarineCorpsBase,Camp

Pendleton. Unpubl. Report. November. 46 pp.

Olivieri, I., Y. Michalakis,andP.H. Gouyon. 1995. Metapopulationgeneticsand

theevolution ofdispersal.Amer. Nat. 146: 202-228.

O’Farrell, M.J. 1974. Seasonalactivity patternsofrodentsin asagebrush

community. J. Mammal. 55: 809-823.

90

Pavelka,Mark. 1997, 1998. Biologist, U.S. FishandWildlife Service. Personal

communication.

Pearson,O.P. 1964. Carnivore-mousepredation: an exampleof its intensityand

bioenergetics.J. Mammal.45: 177-188.

Perlman,D. 1997. Hungrypestshowsdangersofbiological ‘hired guns’. San

FranciscoChronicle. August22.

Pimm,S. L. 1991. Thebalanceofnature: ecologicalissuesin theconservationof

speciesand communities. TheUniversityofChicagoPress,Chicago. 434

pp.

Price,M.V. 1997. Letterto theU.S. FishandWildlife Serviceregardingthe

Pacific pocketmouseon DanaPoint. November21.

Randall,J.W. 1994. Otherinvasivenon-nativeplantsin Californiawildlands and

naturalareas. Pp. 61—67 in: Arundodonaxworkshopproceedings,Friday,

November19, 1993. TeamArundoandCaliforniaExotic PestPlant

Council.

Raup,D. M. 1991. Extinction. Bad GenesorBadLuck? W.W. Nortonand

Company,NewYork andLondon. 210 pp.

Salata,L. 1981. SantaMargaritaEstuaryResourceValuesandManagement

Recommendations.U.S. FishandWildlife Serviceunpublishedreport,

LagunaNiguel FieldOffice, LagunaNiguel,California.

SapphosEnvironmental(SAPPHOS). 1997. Memorandumfor therecord

regardingfinal reportof thePacific pocketmousesurveyat LAX/El

SegundoDunesin supportof theLAX 2015 MasterPlanProject.September

30.

91

Shaffer,M. L. 1981. Minimum populationsizesfor speciesconservation.

BioScience31(2): 131-134.

Silver, D. 1997. Letter to theU.S. FishandWildlife ServiceregardingthePacific

pocketmouseon DanaPoint. November12.

Silver, L.H. and K.L. Drumm. 1996. Letter to theU.S. FishandWildlife Service

regardingthePacific pocketmouseon DanaPoint. January26.

Slatkin, M. 1994. Geneflow andpopulationstructure.Pp. 3-17 in.~ L.A. Real

(ed.),Ecological Genetics.PrincetonUniv. Press,Princeton,New Jersey.

Soule’,M.E. 1980. Thresholdsfor survival: maintainingfitnessandevolutionary

potential. Pp. 15 1-170 in.~ M.E. Soule’ andB.A. Wilcox (eds.),

ConservationBiology: An evolutionary-ecologicalperspective.Sinauer

Assoc.,Sunderland,Mass.

Soule’, M.E. 1996. Letter to theU.S. FishandWildlife Serviceregardingthe

Pacific pocketmouseon DanaPoint. January27.

Soule’,M.E., A. Albertsand D. Bolger, 1992. Theeffectsofhabitatfragmentation

on chaparralplantsandvertebrates.Oikos63: 39-47.

Spencer,W.D. 1997. Letterto U.S. FishandWildlife Serviceregardingcomments

on theDraft RecoveryPlan for thePacific PocketMouse. November24.

Stephens,F. 1906. CaliforniaMammals. WestCoastPublishingCompany. San

Diego.

St. John,Ted. 1996. Soil Ecologist,Treeof Life Nursery,California. Personal

communication.

Taylor,E.W. andJ. Tiszler. 1991. Themammalsof theTijuanaEstuary. In:

TijuanaEstuaryrestorationprogram: draftenvironmentalimpact

92

report/environmentalimpactstatementwith appendices.CaliforniaCoastal

ConservancyandU.S. FishandWildlife Service(Region1 SouthCoast

RefugeComplex).

Tear,T.H., J.M. Scott,P.H. Hayward,andB. Griffith. 1993. Statusandprospects

for successoftheEndangeredSpeciesAct: A look atrecoveryplans.

Science262: 976-977.

Tear,T.H., J.M. Scott,P.H. Hayward,andB. Griffith. 1995. Recoveryplansand

theEndangeredSpeciesAct: Arecriticismssupportedby data?Cons.Biol.

9:182-195.

Templeton,A.R., K. Shaw,E. Routman,and S.K. Davis. 1990. Thegenetic

consequencesofhabitatfragmentation.Ann. Mo. Bot. Garden77:13-27.

Terborgh,J.andB. Winter. 1980. Somecausesofextinction. Pp. 119-133in.~

ConservationBiology. An Evolutionary-EcologicalPerspective,M.E.

Soule’ andB. Wilcox, eds. SinauerAssociates,Inc., Sunderland,Mass.

USDA (U.S. Departmentof Agriculture,Agriculture ResearchService). 1997.

Effectsofbiological controlof saltcedar(Tamarixramosissima)on

endangeredspecies,biologicalassessment(Draft). October17.

U.S. Fish andWildlife Service. 1985. Endangeredand threatenedwildlife and

plants; determinationofendangeredstatusandcritical habitatfor three

beachmice. Final rule. 50 FederalRegister23872-23886.Washington,

D.C.,June6, 1985.

U.S. Fishand Wildlife Service. 1987. Recoveryplanfor theChoctawhatchee,

PeridoKeyandAlabamaBeachMouse. U.S. Fishand Wildlife Service,

Atlanta,Georgia. 45 pp.

U.S. Fish andWildlife Service. 1993. Endangeredandthreatenedwildlife and

plants; determinationof threatenedstatusfor thecoastalCalifornia

93

gnatcatcher.Final rule. 58 FederalRegisi~er16742-16757.Washington,

D.C.,March30, 1993.

U.S. FishandWildlife Service. 1994a. Pacific pocketmousesurvey,International

WastewaterTreatmentPlant,TijuanaRiver Valley, SanDiegoCounty,

California. Reportpreparedfor theEnvironmentalProtectionAgency,

InternationalBoundaryandWaterCommission,andtheCorpsofEngineers.

CarlsbadField Office,FederalProjectsBranch,June1994.

U.S. FishandWildlife Service. I 994b. FederalFishandWildlife permitto take

thePacificpocketmouse. PermitNo. PRT 787041 issuedto Phillip

Brylski, May 10, 1994with SpecialTermsandConditions. Office of

ManagementAuthority, Branchof Permits,Arlington,Virginia.

U.S. FishandWildlife Service. 1994c. EndangeredandThreatenedWildlife and

Plants;DeterminationofEndangeredStatusfor thePacific PocketMouse

(Final Rule). DepartmentoftheInterior,FishandWildlife Service,

Washington,D.C. 59 FederalRegister49752-49764.

U.S. Fish andWildlife Service. 1995a. Pacific PocketMouseSurveysat Goat

CanyonConstructionStagingSite for theInternationalBoundaryand Water

CommissionInternationalWastewaterTreatmentPlantProject,SanDiego

County,California. Reportpreparedfor theU.S. Army CorpsofEngineers.

CarlsbadField Office, May, 1995.

U.S. FishandWildlife Service. 1995b. ResultsofTrappingSurveyfor Pacific

PocketMouse, TijuanaSloughNationalWildlife Refuge. Reportprepared

for U.S. FishandWildlife Service,SouthernCaliforniaCoastal(Refuge)

Complex. CarlsbadFieldOffice, FederalProjectsBranch,June2, 1995.

U.S.Fish andWildlife Service. 1997. FishandWildlife News,September1997.

U.S. FishandWildlife Service,Washington,D.C.

94

U.S. Fish andWildlife Service. 1998. 1997Pacific pocketmouse(Perognathus

longirnembrispacificus) surveyon theDanaPointHeadlands.Report

preparedfor U.S. FishandWildlife Service,CarlsbadField Office.

von Bloeker,J.C. 193 la. Perogna(huspac~ficusfrom thetypelocality. J.

Mammal. 12: 369-372.

vonBloeker,J.C. 193 lb. Extensionof rangeofPerognathuspac~ficus.J.

Mammal. 12: 431-432.

von Bloeker,J.C. 1932. A newraceof Perognathuslongimembrisfrom southern

California. Proceedingsof theBiological SocietyofWashington45: 127-

129.

Wilcox, B. A. 1980. InsularEcologyandConservation.Pp.95-117in:

ConservationBiology. An Evolutionary-EcologicalPerspective,M.E.

Soule’ andB. Wilcox, eds. SinauerAssociates,Inc., Sunderland,Mass.

395 pp.

Williams, D.F. 1986. Mammalianspeciesof specialconcernin California.

Wildlife ManagementDivision AdministrativeReport86-1. California

Departmentof FishandGame,Sacramento.112 pp.

Williams, D.F., H. Genoways,andJ. Braun. 1993. Taxonomy.Pp.38-196in:

Biology of theHeteromyidae,H. GenowaysandJ. Brown,eds. Special

PublicationNumber10, theAmericanSocietyofMammalogists;August

20, 1993.

Wilson,E.O. 1992. TheDiversity of Life. TheBelknapPressof Harvard

UniversityPress. Cambridge,Mass. 424 pp.

Zedler,P.H. 1996. Vegetationdynamicsandvegetationmanagementin coastal

sagescrub. In: ResearchandLandManagementConference;SanDiego

Zoo. September12-13.

95

Zembal,R. 1984. FishandWildlife ServiceCoordinationAct Reportfor Santa

MargaritaRiver Project,SanDiegoCounty,California. A reportoftheU.S.

FishandWildlife Service,LagunaNiguel,California,preparedfor theU.S.

Army CorpsofEngineers,Los AngelesDistrict.

96

APPENDIX 1

GeneticAnalyses

(Derivedandadaptedfrom adraftprotocoldevelopedby theMorro Bay

KangarooRatRecoveryTeam)

Recoverycriteriamustreflectathoroughunderstandingofthepopulationgenetics

andpopulationdynamicsof thespecies.Uncertaintywithin thesetwo areasis

currentlyhigh. Knowledgeconcerninggeneticvariability andpopulationdynamics

ofPacificpocketmicemaybe crucial to implementingactionsnecessaryto prevent

theextinctionofthesubspecies.

Thegeneticanalysesdescribedbelowshouldprovidefor abasicunderstandingof

P. longimembrispopulationgenetics.Thefollowing representsan outlineof

surveysandtasksnecessaryto providetheminimumofinformationnecessary,how

it couldbestbe collected,and howit canbe integratedinto thedecision-making

process.Specificcircumstancesaswell asthestateoftechnologywill likely

dictatewhich of thegeneticanalysismethodsdescribedbelowarenecessaryand

feasible.

Tissuesampling

Tissuesamplescouldbe obtainedfrom Pacificpocketmousecapturedin thefield

(whetherreleasedatthesiteof captureor takeninto thecaptivebreedingcolony).

Necessarypermitsandapprovaloftraining for personnelshouldbeprovidedby the

ServiceandtheCaliforniaDepartmentofFishand Game. A pie shapedwedgeof

tissue(chordof 1.5 mm andaradiusof2 mm)cut from themarginoftheear

shouldbe collectedusingstandardDNA vouchercollectionmethods.Blood from

theinfraorbitalsinusshouldbe collectedif an electrophoreticsurveyof blood

proteins(proteinelectrophoresis)is theonly geneticsurveyto be attemptedandif

handlingandbleedingis doneby a highlyexperiencedcollector. Thesetissues

shouldbe storedin theMuseumofVertebrateZoology (UC Berkeley),in an

97

AmericanSocietyof Mammalogist-approvedfrozentissuecollection,grantedthat

thecuratorsaregivenfull andperpetualpermissionto administerthosetissues.

An alternativeto suchintrusivetissuesamplingwasrelatedby Dr. JerryBoggs

(1997):

DiscussionsI havehadwith Dr. David Woodruffof[University of

CaliforniaSanDiego] indicatethatit is not necessaryto damage[Pacific

pocketmice] to conductsamplingandtyping...Dr. Woodruff indicatedthat

it is possibleto establishgenotypesthroughstrandsof hair (including the

root). As few assix (6) strandswould be sufficient. Thesesamplesshould

be placedin a paperenvelopeprior to processing.Animals to besampled

canbe markedwith a wire transmitterinsertedinto looseskin (asdonewith

lab mice) andthenscannedwhentrappedsubsequently.

Anotherlessinvasivealternativeis to usefecal analysisasaway to extractDNA

from individuals.

Surveyofcurrentgeneticvariation

Populationsizesamplesof thePacific pocketmouseandclosely-relatedspecies

shouldbe surveyedfor geneticvariation. Thespecifictestsandanalysesnecessary

to accomplishthis objectivewill be determinedafterconsultingstudieson other

heteromyidspecies.This databaseshouldbe usedto estimate: (1) the level of

geneticpolymorphismin thePacific pocketmouserelativeto otherpocketmouse

or heteromyidpopulations;(2) therelativegeneticeffectivepopulationsize(Ne) as

comparedto otherheteromyids;(3) the level ofgeneflow (if any) betweenPacific

pocketmouseandotherrelatedtaxa(four) andthecomparativesystematic

relationshipsandgeneticdifferentiationofP. iongimembris.

SurveyhistoricalmitochondrialDNA variation

Using museumstudy skinslocatedattheMuseumofVertebrateZoology

(University ofCaliforniaat Berkeley),SanDiegoNaturalHistory Museum,Santa

BarbaraNaturalHistory Museum,Los AngelesNaturalHistory Museum,andother

98

locales(Erickson1993),pre-bottleneckgeneticvariability shouldbe evaluated.

Thisevaluationmaybe usedin estimationsof: (I) theabsolutereductionin genetic

variation resultingfrom thecurrentpopulationreductionand(2) therelativechange

in the level of inbreeding.

SurveynuclearDNA variation

Usingcollectedskin samples,nuclearDNA shouldbe testedfor geneticvariation.

NuclearDNA will provideestimatesof heterozygosityandpossiblyestimatesof

geneticdifferentiationrelativeto othercloselyrelatedpopulations.As such,it

couldbe an importantmicro-managementtool in captivebreeding. In addition,

screeningnuclearloci (e.g.,usingsingle-strandconformationalpolymorphism,

denaturinggradientgel electrophoresis,orrelatedmethods)would be lesscostly

and moretime efficient thansequencingthem. If significantvariationis found,

DNA sequencesshouldbe obtainedin orderto evaluatetherobustnessof

parametersestimatedin studiessuggestedabove. BecausenuclearDNA is

biparentallyinherited,in contrastto strict maternalinheritanceofmitochondrial

DNA, asurveyof nuclearDNA would: (1) validatetheresultsobtainedfrom

surveyinga singlelocus (mt DNA) and(2) elucidateany differencesin genetic

structuringdueto life history variationbetweenmalesand females.Specifically,a

surveyofnuclearDNA couldsuggestdifferencesin dispersalstrategiesand it

would permit comparisonsofthevariancein reproductivesuccessbetweenthe

sexes. If thesurveyof nuclearDNA wereextendedto includesamplesfrom

museumspecimens,thenmorerobustconclusionscouldbe reachedregarding

historicalinbreedinglevelsaswell astheabsoluteamountof lossin variability due

to thecurrentpopulationbottleneck.

ConductmicrosatelliteDNA analysis

This analysiswouldprovideameasureof populationheterozygosity,andmaybe

requiredto obtainall desiredinformationfrom geneticassessments.However,

techniqueswill needto be workedout for pocketmice. This approachgives fine

scalespatialandtemporalinformationregardingpopulationstructure,geneflow,

andinbreeding. It is probablyabettercomplementto mitochondrialDNA

99

assessmentsthannuclearDNA sequencingwould be. However,the technical

applicationofmicrosatelliteDNA analysisis still in thedevelopmentalstages,

particularlyfor heteromyids.Becausethetechnicalconstraintsare temporary,

microsatelliteDNA analysisshouldbe givenseriousconsiderationonceit becomes

routinelyapplicable. Ear tissuewould be appropriatefor this form of genetic

evaluation.

Surveygeneticvariationin bloodproteins

Geneticvariationin bloodproteinscouldbe evaluatedusing standardprotein

electrophoretictechniques.Blood samplecollectionsshouldbe doneonly by

personswho havedemonstratedexpertisein this area. This surveyprovidesthe

leastexpensiveand leastsensitivesurveyof geneticvariation. Potentially,

estimatescouldbe obtainedfor someof theparametersestimatedin othertasks.

However,it is unlikely that this surveywould providea sufficiently fine level of

resolution,unlessPacificpocketmice are highlydifferentiatedfrom otherlittle

pocketmicetaxa.

100

APPENDIX 2

EssentialCaptiveBreedingProtocolElements

(Adaptedfrom a draftprotocoldevelopedby theMorro Bay KangarooRat

RecoveryTeam)

If captivebreedingshould becomenecessary,thePacific pocketmousewill require

an immediaterapid increasein populationsizeto retaingeneticvariationand

protectremainingpopulationsfrom continuingdeclineand/orstochastic

catastrophe.Oncecaptivebreedingis deemednecessary,efforts mustbe madeto:

1) rapidly increasethetotal Pacific pocketmousepopulationsize;2) securea

geneticpool isolatedfrom thepotentialnaturalandhumaninduceddisastersin the

wild; and3) providea long-termpopulationandgeneticresourcefor supplementing

existing wild populationsand/orestablishingnewwild populationsin thefuture.

Theinterdependentactionsoutlinedherewould no longerbe necessaryif andwhen

successfullyreintroducedor translocatedPacific pocketmice populationsbecome

viable andself-sustaining.

A Pacific pocketmousecaptivebreedingprotocolshouldcontain,at aminimum,

thefollowing tasksandobjectives:

Breedsurrogatespeciesin captivity t~ establishcaptivebreeding/management

parameters

Becausereproductionmayoccurin only a small fractionofthewild animals

broughtinto captivity, establishmentof a self-sustainingcaptivecolonywill require

the initial acquisitionofa largenumberofanimalsfrom thewild. Pacific pocket

mousepopulationscurrently maybe too small andfragmentedto sustainviable

numbersin thewild aftera“take” to establisha captivecolony. Therefore,it is

recommendedthat techniquesfor captivemanagementandreproductionbe

developedon acloselyrelatedsurrogatespeciesfirst to maximizetheprobability of

successwith Pacific pocketmice ata later time.

101

Establishandmaintain~populationof at least50 individuals oftheselected

surrogatespecies

Becauseotherheteromyidrodents(i.e., kangaroorats)do notbreedreadily in

captivity, an initial colonyofat least50 wild-caughtanimalsis thoughtto be

necessaryto achievea reasonableprobabilityofcaptivereproduction.Although

geneticmanagementof thesurrogateis not strictly required,techniquesshouldbe

developedfor maximizingfounderreproduction,which will be of benefitwhenand

if thecaptivepropagationof Pacific pocketmice begins. Obtainingreproduction

from 20 of 50 wild-caughtanimals(40 percent)would be regardedasasuccessful

achievement.

Maintenanceofacaptivecolonyasnearto Pacificpocketmousehabitataspossible

(butnot within theknowncurrentrange)in Californiais importantfor anumberof

reasons.A colonysituatednearthenaturalrangeof thePacific pocketmouseand

surrogatespeciesgreatly simplifiesacquisitionofanimalsfrom thewild and later

theexchangeofanimalsbetweencaptivity andthewild when

reintroduction/translocationefforts begin. It also helpsfosterthenecessary

interactionbetweenin situ andex situ Pacific pocketmouseconservationand

researchefforts, theapplicationof informationobtainedon wild populationsto

captivemanagement(e.g., behavioralandnutritional requirements).Finally, a

California locationshouldalsoenhanceinteractionwith local communitygroups,

businesses,institutionsofhigherlearning,andzoosthatcouldpotentiallyprovide

critically neededresourcesandassistancefor theconservationprogram. However,

thecaptivebreedingfacility for thesurrogatesubspeciesshouldnot be located

within therangeof thePacificpocketmouse. Although interbreedingofsubspecies

is commonin nature,mixing of geneticlineagesasaresultofaccidentalreleasesof

animalsshouldbe avoided.

Conductfocusedresearch~ reproductivebehavior~ physiologyat asuitable

facility that will ensurethegoalQfdoublingth~ captivepopulationevery~ years

andto determinecritical factorsnecessaryfur captivebreeding~fthePacific pocket

mouseandotherendangeredheteromyidrodents

102

Considerabletime,money,andotherresourceshavebeendevotedto captive

breedingofMorro Bay kangarooratsduring thelastdecadewith mixed results.

Althoughafirm foundationof captivehusbandryhasbeenestablished,consistent

progressin captivereproductionhasbeenvery limited andis still critically needed.

Thus, it cannotbe assumedthat thecaptivebreedingof Pacific pocketmice is

assured.Focusedresearchon reproductionin thesurrogateshouldbe continued

with thespecificobjectiveof doublingthecaptivepopulationevery2 years.

Adequateandpredictablefunding for captivepropagationis essentialto ensure

full-time animalcareandresearchactivitiesfor an initial colonyof about100

animalsthathopefullywill doubleevery 2 years.

Developintensivehusbandry~ breedingtechniquesIh~! will increasecaptive

carryingcapacityIQ ~point whereseveralinstitutionsareparticipatingin !h~

captivebreedingprogram

A rapidanddramaticincreasein thenumberofPacific pocketmice would be

requiredto producethecaptivepopulationandgeneticpool necessaryto ensurea

long-term,self-sustainingcaptivepopulation. It is unlikely, andeveninadvisable

thatany singleinstitutionwill be ableto accommodatethis largenumberof

animals. Therefore,it is recommendedthat avarietyof Californiainstitutionsbe

recruitedasadjunctbreeding/exhibitionfacilitiesto increasecaptivecarrying

capacity. All recruitedinstitutionsshouldbe managedunderasinglemanagement

schemealongthelinesofthe SpeciesSurvivalPrograms(SSP)oftheAmerican

AssociationofZoologicalParksandAquariums(AAZPA). Accordingly,it would

be necessaryto developstandardizedhusbandryandbreedingprotocolsassoonas

theneedarises.

Develop.implement.and evaluatelaboratorytechniquest~preparecaptiveanimals

for reintroductionand/ortranslocationusingsurrogatespecies

Resultsfrom experimentalreintroductionsandtranslocationsofsurrogatespecies

should beusedto developtechniquesthat areexpectedto increasethechancethat

anycaptive-bornPacificpocketmice will becomesuccessfullyestablishedin

managedhabitats.An experimentalapproachshouldbe adoptedthat is integrated

103

with thecaptive-breedingprogram. Thetype, length, andintensityof training

necessaryshouldbe investigatedto maximizeshortandlong-termsuccessof

animalsintroducedto thewild. Also, sociallearningeffects(adult-juvenile,

sibling-sibling)that are importantto successfulestablishmentin thewild should be

elucidated.

Develop~ implementtechniquesfQi anti-predatortraining

Use conditioningtechniqueson captiveanimalsto establishappropriate

anti-predatorresponsesin animalsprior to their releaseinto thewild. Evaluate

cross-modalandcross-predatortransferof learnedbehaviors.

Develop~n4implementtechniquesfQx foragin2training

Evaluatediet selectionandforagingstrategies(e.g.,harvestrates,micro-habitat

choice,foraging-predationinteractions)in developing,captiveanimals. Testfood

preferencesin captiveanimalsandincorporatethis informationinto habitat

improvementprograms. Informationfrom theseexperimentsalsoshouldbe

incorporatedinto foodsupplementationprogramsthatmaybe undertakenon wild

populations.

Develop~ implementtechniquesfQr socialtraining

Investigatesocialandcompetitiveinteractionsin youngcaptiveanimalsandthe

influenceofsocialinteractionson timing ofsexualmaturityandcompetence.

Determinetherole ofsiblingsandparentsin modifying earlysocialinteractions.

Ascertainthedevelopmentof survival skills to optimizetiming ~frelease

Comparethespeedof acquisitionand maintenanceofrelevantbehaviorsat different

developmentalstages.Investigatetheway in which thedevelopmentof various

skills (e.g.,social,foraging,anti-predator)interact.

104

Develop~ captivepropagationprogramfor thePacific pocketmousethatwill

provide~ securesourcepopulationfor reintroductions.Makeprovisionsto obtain

sufficientanimalsfrom wild populationsto ensurethat atk~t 2Q(preferably 100~

contributingfoundersareobtained

Theultimateobjectiveofthecaptivebreedingprogramis to propagatePacific

pocketmice in captivity in sufficient numbersto providesecure,geneticallydiverse

adjunctcaptivepopulationsto thewild population(s)to buffer againstextinctionof

thesubspeciesin theeventofcatastrophicextinctionofthewild population,andto

provideanimalsfor future reintroductionefforts. From ageneticstandpoint,all

animalsthat canbe capturedin thewild shouldbe placedin aheavilymanaged

captivebreedingprogram. Time is paramountbecauseall genotypesthatcannotbe

incorporatedintoa rapidlygrowingcaptivepopulationwill be effectively extinct.

Captivebreedingofthetargetsubspecies(Pacific pocketmouse)shouldproceedas

soonassufficientprogresshasbeendemonstratedfor thesurrogate.

Fundand maintaincaptivepopulationslargeenoughto preserveatleast90 percent

ofgeneticvariationof thefounderpopulationfor at least10 years. A relatively

largenumberoffoundersfor thecaptivebreedingprogram,preferably100, is

recommendedto minimizethelossofgeneticvariationandachievesufficient

numbersof animalsto supportashort-term(atleast10 years),growingcaptive

populationof at least500animalsthatwill be ableto supplyanimalsfor

reintroductionefforts. A cooperativefundingeffort betweenFederal,Stateand

otheragenciesandinstitutionsshouldbeinitiated. If determinedto be prudentand

necessary,Serviceandotheragenciesandpartieswill needto fundaprogramof

sufficientdurationto ensurethat anexpandingcaptivecolony canbe maintained

intactat a singlesite for long enoughto establishtheefficacyofcaptivebreeding

underthebestavailableconditions. Supplementalor alternativesourcesoffunding

shouldbe sought. Oncecaptivebreedingis determinedto be necessary,sourcesof

privateandFederalfundingto supportthecaptivebreedingeffort shouldbe

cultivatedimmediately. Fundingsourcesor endowmentsshouldprovideat a

minimumof $50,000peryearto create,andthensustain,thecaptivebreeding

effort.

105

Onceadequatetechnologies£Qr captivebreedinghavebeendeveloped,collect

additional Pacific pocketmice andestablishat leasttwo separatecaptive

populationsto achievethe goal~fdoublingIh~ populationevery 2 years

Acquisition ofanimalswill requireresearchandmanagementaccessto privately

ownedlands that supportapopulationof Pacific pocketmice. A long-term.

self-sustainedcaptivecolonyshouldbe housedin at leasttwo, preferablymore,

California sitesto ensurethat acatastrophiceventatoneinstitution(e.g., infectious

disease,fire, earthquake)will not decimatetheentirecaptivepopulation. A genetic

and demographicmanagementplanshouldbe initiated to managethecaptive

populationto minimize inbreeding,ensureparityoffoundercontributionsandaffect

a stableagedistributionin thecaptivepopulation. Applicationofrationalgenetic

anddemographicmanagementtechniqueswill readily enableidentificationof

“surplus’ animalsbasedon theirgeneticmakeup,meankinship, age,fecundity, etc.,

so that geneticallyanddemographicallysoundadjunctcaptivepopulationscanbe

establishedfor reproduction,exhibition,and/oreducationprogramsat participating

institutions.

Pursue~ programofresearchon thecaptivepopulationthatcanbe of benefitto

field conservationefforts

Certaintypesofinformationpertinentto conservationandmanagementcanbe

collectedmorerapidly and cost-effectivelyin the laboratorythan in the field (e.g.,

behavioralandlife history data). A successfulbreedingcolonyofPacificpocket

micewill generateconsiderabledataneededto designanintegratedin situ andex

situ managementprogramfor therecoveryof thesubspecies(and,hopefully,other

species).It is recommendedthat aprogramfor thecollectionofthesedatabe

developedimmediatelyaftertheneedarises.

Gatherinformationon life history.k~hayior ~n4reproductivebiologyih~ ~jij

provideinformationfor developingdemographic~n4geneticmanagement

techniquesfor the in ~h~apopulationandfor futurereintroductionandtranslocation

efforts

106

Muchof thelife history anddemographicinformationnecessaryfor in situ and ex

situ populationmanagementmodelingcanbe collectedopportunisticallyby using

soundandfocusedrecord-keepingpractices.However,adatacollectionparadigm

shouldbe devisedto ensurethat all relevantdataarecollectedduring thecourseof

thecaptivebreedingprogram.

107

APPENDIX 3

Summary of the Agencyand Public Commentson the

Draft Pacific PocketMouseRecoveryPlan

In compliancewith our (Service)policy on informationstandardsundertheAct (59

FederalRegister34270,July 1, 1994),wesolicitedtheexpertopinionsoffour

appropriateand independentspecialistsregardingtheDraft PacificPocketMouse

RecoveryPlanin relationto pertinentscientific orcommercialdataandissues.

Commentswere receivedfrom oneofthereviewers. Additionally,on September

25, 1997,weannouncedtheavailability oftheDraft RecoveryPlanfor public

review(62 FederalRegister186, September25, 1997). The60-daypublic review

commentperiodfor Federalagencies,Stateandlocal governments,andmembersof

thepublic endedNovember24, 1997. Fifteenletterswerereceivedduringthe

commentperiod,eachcontainingvaryingnumbersof comments.

The number ofletters receivedby affiliation:

Federalagencies 2 letters

Stategovernment 0 letters

Academia/professionals 7 letters

Environmental/conservationorganizations 2 letter

Local governments 0 letters

Business/Industry 3 letters

PrivateCitizen I letter

Summary of Significant Commentsand ServiceResponses

Wereviewedall ofthecommentsreceivedduring thecommentperiod. Comments

receivedwerevaried,someprovidingrecommendationsfor research/conservation

strategiesordescriptionsandinformation. Commentswerebothcritical and

favorableof theapproachtaken. Severalcommentersprovidedvaluableadditions

andcorrectionsto theDraft RecoveryPlan. Thesearegratefullyacknowledgedand

108

incorporatedin theappropriatesectionsoftheFinalRecoveryPlan. Most

applicablecommentshavebeenaddressedin, or incorporatedinto, thebody of the

Final RecoveryPlan;additionalsubstantivecommentsandour responseto eachare

summarizedasfollows:

Comment: OnecommenterindicatedthattheDraft RecoveryPlanappearedto be

biasedagainstfire asacausativeagentin habitatalteration.

Response:Successionof habitatfor thePacific pocketmouseasit pertainsto its

ecologyand occupationis little understood.We (theService)acknowledgethat

additionalresearchis necessary(and calledfor in this Final RecoveryPlan)to

elucidatehabitatsuccessionfor this species.We revisedtheFinal RecoveryPlanto

greaterreflectthepotential short-and long-termbenefitand/orharmthatcanresult

from fire.

Comment: Two commentersindicatedthat theDraft RecoveryPlanfailed to

addressexotic grasslandsashabitatfor thePacific pocketmouse.

Response:SomeofthePacific pocketmicefoundon CampPendletoncurrently

occurin non-coastalsagescrubhabitats,includingnon-nativegrasslandsand

disturbedareas.Anecdotalevidencesuggeststhattheareasof densegrasslandsare

not occupied(to a level ofbeingdetectableduring surveys),but thesmall coastal

sagescrub,bareground,andlow densitynon-nativegrasslandpatcheswithin the

moredensegrasslandsareoccupied. It is unclearwhetherthemice occupythe

densegrasslandsin low numbers,usethemonly for movementto/from thesmaller

patchesof suitablehabitat,oronly moveacrossthoseareasfollowing burnevents

(which arequite frequentwithin this portionof theBase)whenthevegetationis less

prohibitiveto movements.TheFinal RecoveryPlanreflectsthis information.

Comment:SeveralcommentersindicatedthattheDraft RecoveryPlanshouldtreat

theDanaPointHeadlandspopulationasessentialto therecoveryofthespecies.

109

Response:This FinalRecoveryPlannotesthat all knownextantpopulationsare

essential,including theDanaPointHeadlandspopulation.

Comment:Onecommenternotedthat CampPendletonhasnow surveyedmostof

thecoastalzonebetweenthepopulationsknownon Baseandno newpopulations

havebeenfound. This commenternotedthat this newdatadoesnot supportthe

theorythat”. . . CampPendletonpopulationscould be partof larger

metapopulation.”

Response:Overthe long-term(100-yearsplus), it is expectedthathabitatsuitable

for occupationby thePacific pocketmousedynamicallyshifts in spaceandtime in

responseto fire, drought,andotherphysicalprocesses.Populationsmaybecome

established,thenextirpated,andthenrecolonized,in responseto thesephysicalor

otherfactors. Thetwo main concentrationsofknownPacific pocketmouse

occupationon Basearecurrentlyratherdistantfrom eachother. Historic habitat

waslikely suchthatthepotentialfor populationsdynamicallyoccupyinghabitats

betweenthecurrentlyoccupiedareason CampPendletonwasatleastmoderate.

Thus,thepotentialfor a seriesofpopulationson what is now CampPendleton

functioningasametapopulationin thepastis moderate.Barringartificial

impedimentsto movement,and/orchangesin thephysical(orother)processes

affectinghabitatsuitability, continuedpotentialexistsfor metapopulationdynamics

to existon Basein thefuture aslong ascontiguityremains.Historically thePacific

pocketmousewasknownfrom a few, disjunct,locations. Dataareunavailableto

confirmor denyfunctionasametapopulation.A currentlack ofdetectable

occupationthroughouta zoneofpotentialhabitatdoesnot eliminatethepossibility

thatametapopulationdynamicexistsor that it could becomefunctionalin the

future. A reasonableapproachto protectionofthespeciesis to continueto evaluate

andprovidefor this potential.

Comment: OnecommenternotedthattheDraft RecoveryPlanrequiredresearchon

thelife history, ecology,andpopulationbiologyofthePacific pocketmouse. This

commenterquestionedlisting thespeciesprior to assemblingthis information.

110

Response:As anothercommenternoted,relatively little is knownof the life history

andbiology ofthePacific pocketmouse. We acknowledgethatadditional research

is necessaryto elucidatethe life history,ecology,andpopulationdynamicsofthe

species.Becausetheresultsoftheseproposedstudiesarenot yetavailable,weare

currentlychargedwith incorporatingthebestavailableinformationinto theplanand

in that regardhaverepeatedlyconsultedwith therecognizedexpertson thespecies

and its habitats. Eventhoughthelife history,ecology,andpopulationbiology for

this speciesis poorly known,generalbiological tenetsareprimarily applicablein

thecaseof listing thePacific pocketmouse,and in thedevelopmentoftherecovery

strategy. Thethreatsto thespeciesaredeterminableandforeseeable.Giventhe

extentof thedocumentedthreatsfacingthespeciesandits current,knownrange,we

continueto conclude,basedon acompositeofthebestinformationavailable,that

thespeciesis imperiledandpresentlyrequiresimmediateattentionto preventthe

extirpationofimportantpopulationsor actualextinctionofthespecies.Waiting to

assemblebetterinformationon thebiologyofthespeciesbeforelisting would only

delaynecessaryprotectionfor thespeciesto aperiodwhenevenfeweroptionsfor

protectionfrom extinctionwould be available.

Comment: Severalcommentersindicatednotedthatpopulationviability analysis

(PVA) is a usefultool in conservationbiology, but that it shouldnot be usedasan

absolutemeasureof successor failure of apreserveorrecoveryplan. One

commenterlaudedus(theService)for our apparentwillingnessto usethetoolsof

modemdemographicmodelingto helpdeterminehowpopulationviability is likely

to beaffectedby alternativemanagementplans.

Response:WeagreethatPVAs canbe misusedandtheyshould be usedcautiously.

Careshouldbe takento not over-extendthepopulationviability (vulnerability)

analysisapproach.Populationviability analysisis mostusefulfor comparingthe

relativemeritsof alternativepreserveconfigurationorplans. This is indicatedin

theFinal RecoveryPlan.

Comment: Severalcommentersindicatedthat we shouldtreatthePacific pocket

mouseoccurrenceson eitherside of SanMateoCreekon CampPendletonas

separatepopulations.

ill

Response:We havemodified thisFinal RecoveryPlan in its treatmentofthese

occurrencesnearSanMateoCreekto indicatethebestinformationavailable. It is

unknownif theseoccurrenceshistorically functionedasseparatepopulations,asa

singlepopulation,or asametapopulation.Thewarrantedapproachto protecting

theseoccurrencesis to maintainand enhanceconnectivitybetweenthem asif they

aredependentuponeachotherfor exchangeof geneticmaterial and/orutilization of

oneoccurrenceto recolonizetheotherin the caseof extirpation. Without specific

referencesor informationto challengeexistingdata,information,or

recommendations,wecannotassesstherelevance,utility, or relativeimportanceof

newinformation. Becausewe are chargedwith revisingrecoveryplansas

necessary,we encourageall partiesto continueto submitany new informationthat

maybearon therecoveryprocess.

Comment: A couplecommentersquestionedthepracticalityofcompletingthe

actionsthat would resultin delistingofthePacific pocketmouse.

Response:We developrecoveryplans thatdelineatereasonableactionsrequiredto

recoverand/orprotectlisted species.Thestrategyoutlined hereinis not likely to be

easily fulfilled, but it is attainableandreasonablebasedon thebestinformation

available. We definerecoveryby theneedsofthe subjectspecies,including

conservationof theecosystemit dependsupon.

112

Region 1U.S. Fish and Wildlite ServiceEcological Services911 N.E. 11th AvenuePortland, Oregon 97232-4181

September 1998