LIMPOPO LEOPARD MONITORING REPORT CAMERA-TRAP SURVEY 2016 | ZINGELA

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LIMPOPOLEOPARDMONITORINGPROJECT

ZINGELACAMERA-TRAPSURVEY2016

RossPitman*,GarethMann,GarethWhittington-Jones,LisaThomas&GuyBalme

*rpitman@panthera.org(Correspondingauthor)

INTRODUCTION

TheLimpopoLeopardMonitoringProjectaimstoproviderobustdataon leopardpopulationtrends in

Limpopo Province to inform conservation policy andmanagement. Herewe report on a camera-trap

surveyundertaken inZingelaGameReserve (hereafter ‘Zingela’). This is the firstannual survey run in

Zingela.

METHODS

Wedeployed paired camera stationswere setup at 40 locations for a total of 57 days. To ensure all

individuals within the sampled areas had a probability > 0 of being captured, camera-traps were

distributed an average of 2035 m from one another. To maximize the probability of photographing

leopards,camera-trapswereplacedinhigh-useareas,suchasdrainagelines,animalpaths,androads.

Camera-traps were mounted on trees or steel poles located 2–4 meters from the focal movement

pathway. To reduce false photographic captures, we cleared any vegetation that might obstruct the

camera-trap’sfieldofview.Camera-trapswerenotmovedduringthesurveys.Camera-trapimageswere

cataloguedusing camtrapR (Niedballa et al. 2016),within theR Statistical Environment (RCoreTeam

2015).We identified individualsbasedon theiruniquepelagepatternswithin thepattern recognition

software,Wild-ID (Bolgeretal.2012). Inaddition,all computer-assisted identificationsweremanually

verified.

Bayesianspatially-explicitcapture-recapturemodels

Wefollowedthecapturere-captureanalyticalmethods,andhierarchicalmodelformulation,described

by Goldberg et al. (Goldberg et al. 2015) and Royle et al. (Royle et al. 2009). Themodel relates the

observations,yijk,of individual i intrap jduringsamplingintervalktothelatentdistributionofactivity

centers.Observation,yijk, took the valueofone for a capture, and zero if not captured, toproducea

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capturehistoryforallindividualsinalltrapsoverallsamplingintervals.Multipledetectionsofthesame

individual,withinthesamesamplingperiod,weretakenasasinglecapture.Individualscouldbecaptured

onmultipletrapsduringasamplinginterval(24hours).Wefollowedtheformulationoftheobservation

processusedbyGoldbergetal.(Goldbergetal.2015),Gardneretal.(Gardneretal.2010),andRussellet

al.(Russelletal.2012).

Ourspatially-explicitcapture-recapturemodelswereimplementedwithinaBayesianframework

using data augmentation (Royle & Young 2008; Goldberg et al. 2015). Data augmentation adds a

sufficientlylargenumberofall-zerocapturehistoriestocreateadatasetofsizeMindividuals(Goldberg

etal.2015).Augmentationwasconsideredlargeenoughwhenthenumberofaugmentedindividualsdid

nottruncatetheposteriorestimatesofpopulationsize(Goldbergetal.2015;Proffittetal.2015).Data

augmentation in this study was set to 400. We chose a uniform prior distribution from 0 toM on

populationsize(Goldbergetal.2015).Startingvaluesforparameterswere:s=1,q=0.75,ln(a0)=0,b=

0,Y=0,Ysex=proportionofmalessampled.Weusedimproperpriors(-¥,¥)fora0andallbparameters,

(0,¥) fors, (0.5,1)forq,and(0,1)forYand Ysex.ModelswerefitusingMarkovchainMonteCarlo

(MCMC) methods within R, using the SCRbayes package (available at:

https://sites.google.com/site/spatialcapturerecapture/scrbayes-r-package). To account for individual,

sex-specificeffects,weincludedasexcovariatewithinallmodels.Althoughcubs(<12monthsold)were

occasionallycapturedonthecamera-traps,weonlyincludedadultsandsub-adultswithinouranalyses.

Toaccountforheterogeneityinhabitatuseacrossthestudyarea,wemodelledourdensityestimateusing

anexistingresourceselectionfunction(Pitmanetal. inpress)asadensitycovariate(Royle&Chandler

2013;Proffittetal.2015).

Allanalyseswererunusingastatespaceof20km.Modelswererunfor30,000iterations,withaburn-in

of 5,000. To reduce autocorrelation,we thinned theMCMC chains by skipping every other iteration,

resultingin12,500iterationsinourposteriorsample.Weevaluatedmodelgoodnessoffitusingastandard

Bayesian P-value approach (Royle et al. 2013). Convergence of the MCMC chains were assessed by

examiningposteriorparameter-wisetraceplotsandhistograms.Themeanand95%credibilityintervals,

foreachmodelparameter,werethencomputedfromtheseconvergedsamples(Goldbergetal.2015).

Inadditiontoestimatingpopulationdensity,weassessedthedemographiccompositionofthesampled

population.Weestimatedtheageandsexofcapturedleopardsusingtheirrelativebodydimensions,the

presenceofawell-developeddewlap,andfacialscarring(Balmeetal.2012).Weclassifiedleopardsinto

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threeageclasses: juveniles (≤2years), subadults (>2years;≤3years)andadults (>3years).Foradult

males,wedistinguishedbetweenindividuals<7yearsand≥7years.

RESULTS

Camera-trapsurveys:

Thetotalareacoveredbycamera-trapstationsatZingelaamountedto186.2km2.Thesurveyranfrom

the03May2016tothe28June2016,andsamplingeffortcomprised4,480camera-trapnights.Atotalof

29,172photographswererecorded,ofwhich23,134wereindependentcaptures(thisincludesduplicates,

‘blank’ photos, and photos of the research team). A total of 48 different specieswere recorded (see

Appendix1forasummary).Leopardswerephotographedat60%ofcamera-trapstations(24stations;

Figure1).

Figure1.Leopardcapturefrequenciesrecordedatcamera-trapstationsinZingeladuringthe2016survey.Largercirclesindicategreaterleopardactivity.

We identified22 individual leopardscapturedon66occasionsduringthesurveyperiod.Of these, ten

wereclassedasadultfemalesandelevenasadultmales.Fouroftheadultmalesappearedtobeover7

yearsold.Nosub-adultleopardswererecorded,andoneindividualcouldnotbesexed.Despitethelack

Zingela_2016

-22.95

-22.90

-22.85

-22.80

-22.75

28.55 28.60 28.65

Captures 5 10 15

Zingela Game Reserve

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ofsub-adultindividuals,thedemographiccompositionofthepopulationappearsfairlyhealthy(Fig.2).

Theoccurrenceofmaleleopardsover7yearsoldisapromisingsign.

Figure2.Proportionalcompositionofleopardage-sexclassesforZingeladuringthe2016survey.

Spatially-explicitcapture-recaptureanalysisestimatedthepopulationdensitytobe4.84±1.25leopards

per100km2.ThemodelhadsufficientiterationsforMCMCtoconverge,andreportedaBayesianP-value

of 0.54, suggesting excellentmodel fit. Additional survey years will be key to improving this density

estimate and future trends. Analyses of activity patterns indicate that leopards on Zingela are active

duringnocturnalhours,withpeaksatcrepuscularperiods(Fig.3)—asisoftenthecaseforthisspecies.In

contrast, impalaavoidedmovingaroundduringnocturnalhours,butstillappeartoexhibitcrepuscular

movementpatterns(Fig.4).Brownhyaena,ontheotherhand,appearmoreactiveduringpre-dawnand

post-duskperiods(Fig.5);whilstcheetahonZingelaappearmostactiveduringearlymorninghours(Fig.

6).

Unknown AdultMale ≥ 7 YearsMale < 7 YearsFemale Adult

Zingela 2016

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Figure3. Leopardactivitypatterns inZingeladuring the2016 survey.Higherpeaks indicate increasedactivity,whilsttroughsindicateperiodsofloweractivity.

Figure4.LeopardandimpalaactivitypatternsinZingeladuringthe2016survey.Higherpeaksindicateincreased activity, whilst troughs indicate periods of lower activity. Grey shading indicates temporaloverlapbetweenthesetwospecies.

0.00

0.02

0.04

0.06

0.08

Activity of Leopard

Time

Den

sity

0:00 6:00 12:00 18:00 24:00

number of records: 66

0.00

0.02

0.04

0.06

0.08

0.10

Activity overlap: Leopard − Impala

Time

Den

sity

0:00 6:00 12:00 18:00 24:00

Dhat1=0.45LeopardImpala

number of records: 66 / 3509

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Figure5.Leopardandbrownhyaenaactivitypatterns inZingeladuringthe2016survey.Higherpeaksindicate increased activity, whilst troughs indicate periods of lower activity. Grey shading indicatestemporaloverlapbetweenthesetwospecies.

0.00

0.02

0.04

0.06

0.08

0.10

Activity overlap: Leopard − Brown_Hyaena

Time

Den

sity

0:00 6:00 12:00 18:00 24:00

Dhat1=0.81LeopardBrown_Hyaena

number of records: 66 / 255

0.00

0.05

0.10

0.15

Activity overlap: Leopard − Cheetah

Time

Den

sity

0:00 6:00 12:00 18:00 24:00

Dhat1=0.43LeopardCheetah

number of records: 66 / 16

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Figure6.LeopardandcheetahactivitypatternsinZingeladuringthe2016survey.Higherpeaksindicateincreased activity, whilst troughs indicate periods of lower activity. Grey shading indicates temporaloverlapbetweenthesetwospecies.

Astheprimary leopardpreyspeciesonZingela, impalawerecapturedthroughoutthereserve,andon

3,509occasions(Fig.7).BrownHyaenaweresimilarlycapturedacrossthereserve,andon255occasions

(Fig.8).Cheetah,ontheotherhand,werecapturedinfrequentlyonthereserve(n=16occasions;Fig.9).

Figure7.Impalacapturefrequenciesrecordedatcamera-trapstationsinZingeladuringthe2016survey.Largercirclesindicategreaterimpalaactivity.

Zingela_2016

-22.95

-22.90

-22.85

-22.80

-22.75

28.55 28.60 28.65

Captures 100 200 300 400 500

Zingela Game Reserve

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Figure8.Brownhyaenacapturefrequenciesrecordedatcamera-trapstationsinZingeladuringthe2016survey.Largercirclesindicategreaterbrownhyaenaactivity.

Figure9.Cheetahcapturefrequenciesrecordedatcamera-trapstationsinZingeladuringthe2016survey.Largercirclesindicategreatercheetahactivity.

Zingela_2016

-22.95

-22.90

-22.85

-22.80

-22.75

28.55 28.60 28.65

Captures 5 10 15

Zingela Game Reserve

Zingela_2016

-22.95

-22.90

-22.85

-22.80

-22.75

28.55 28.60 28.65

Captures 2.5 5.0 7.5

Zingela Game Reserve

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DISCUSSION

TheLimpopoLeopardMonitoringProjectcontinuestofulfilitsmandatetoproviderobustdataonleopard

populationdensity and trends,which can informmanagementdecisions.Our results suggest that the

leopardpopulationinZingelaisatanexpecteddensity,butfuturesurveyswillcertainlyberequiredto

determinethetruestatusofthis localpopulation.TheprolongeddroughtinLimpopoProvince—much

liketherestofsouthernAfrica—mayhaveinfluencedleopardmovementpatterns,butthiswouldalso

notaffecttheoveralldensityestimate(butrathertheprecisionoftheestimate).Indeed,droughtsoften

representoptimumperiodsforpredators,duetothepoorconditionofpreyandincreasedscavenging

opportunities(Owen-Smith&Mills2006),sowemightevenbedetectingunusuallyhighleoparddensity

estimatesthisyear.Illegalkillingofleopards,bothincidentallythroughbushmeatpoaching(Henschelet

al.2011),intensivegameranchingpractices(Pitmanetal.2016),anddeliberatelyfortheirpeltsandbody

parts,isverylikelyplayingaroleindepressingleopardpopulationsacrossLimpopoProvince.Ittherefore

remainstobeseenwhetherZingela’sleopardpopulationremainsonatrajectoryof±4.8leopardsper

100km2.AcrossmuchofLimpopoProvince,leopardpopulationnumbersaredecreasing.Asaresult,no

leopardtrophyhuntingpermitshavebeenissuedinSouthAfricafor2016,andwehopethattheabsence

of this source of additional mortality will allow a partial recovery of Limpopo Province’s leopard

populations.

ACKNOWLEDGEMENTS

WearegratefultoallthestaffonZingelaGameReserveforallowingaccessandWEIforprovidingsupport

totheproject.

REFERENCES

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APPENDIX1–SUMMARYOFCAPTUREDATA

COMMONNAME NUMBEROFCAPTURESAARDVARK 58AARDWOLF 41AFRICAN_CIVET 45AFRICAN_WILDCAT 35BANDED_MONGOOSE 12BAT 12BAT-EARED_FOX 22BIRD 586BLACK-BACKED_JACKAL 149BLUE_WILDEBEEST 291BROWN_HYAENA 255BUFFALO 15BUSHBUCK 25BUSHPIG 9CARACAL 7CHACMA_BABOON 539CHEETAH 16COMMON_DUIKER 101

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DOG 4ELAND 179GEMSBOK 750GENETTA 1GIRAFFE 257HARTEBEEST 52HONEY_BADGER 8HUMAN 90IMPALA 3509INSECT 2KUDU 753LEOPARD 66LEOPARD_CUB 1LESSER_BUSHBABY 2MELLERS_MONGOOSE 7PANGOLIN 1PORCUPINE 99RESEARCH_TEAM 626ROAN_ANTELOPE 13SABLE_ANTELOPE 33SCRUB_HARE 125SLENDER_MONGOOSE 2SPRINGHARE 28STEENBOK 282TREE_SQUIRREL 1UNKNOWN 624VEHICLE 2948VERVET_MONKEY 41WARTHOG 1014WATERBUCK 115ZEBRA 95