Dung beetles, monkeys, and seed dispersal in the Brazilian Amazon

127 Pages·1999·3.1 MB·English

by  Vulinec, Kevina

DUNGBEETLES,MONKEYS,ANADMASEZEODNDISPERSALINTHEBRAZILIAN
By
KEVINAVULINEC
ADISSERTATIONPRESENTEDTOTHEGRADUATESCHOOLOFTHE
REUQNUIVIERRESMIETNYTSOFFFOLROTRHIEDADEINGRPEAERTOIFALDOFCUTLFOIRLOLFMEPNHTILOOFSTOHPEHY
UNIVERSITYOFFLORIDA
1999
Tothememoryofmybrothers,bloodandspirit:
DavidClover
1939-1997
JohnE.Fischer
1948-1998
and
Zack(TheKing)
1979-1999
ACKNOWLEDGMENTS
Iwishtothankthemembersofmycommittee,CarlBarfield,ColinChapman,
JimLloyd,andMikeThomas,fortheirsupport,advice,andencouragement.I
especiallythankmycommitteechair,JohnSivinski,forhisenthusiasm,support,and
intellectuallyintriguingdiscussions.
Ithankthefollowingorganizationsfortheirfinancialsupportofmyresearch:
TheEntomologyandNematologyDepartmentattheUniversityofFlorida,the
FulbrightCommissionforInternationalStudies,theGahanFoundationatthe
UniversityofFlorida,theCharlesA.andAnneMorrowLindberghFoundation,the
FloridaCenterforSystematicEntomology,theDickinsonAwardforTropical
Agriculture,theWomeninAgricultureClub,andtheJ.D.TurnerFoundation.
InBrazil,IamgratefultoOConselhoNacionaldeDesenvolvimento
CientfficoeTecnologico(CNPq),InstitutoNationaldePesquisasdaAmazonia
(INPA),andMuseuParaenseEmflioGoeldi(MPEG).Iamespeciallythankfulto
ClaudioR.V.daFonsecaofINPAforhisfriendshipandimmeasurablehelp.Ialso
wishtothankPedroL.B.Lisboaforhisassistance.
SpecialthanksareduePhoebeWilsonforthemaps,DavidAlmquistand
FreidaAnsoanuurforsortinginsects,BruceGillandDaveEdmondsforhelpwith
identifications.IamverygratefultoKenPortier,GalinJones,andVictorHuforhelp
withthestatistics.IthankGinaPoseyandSidMayerfortheircomputerand
programminghelp.
Ialsothankmysons,ColemanandCoreyKanefortheirhelpinBrazilandthe
States,andtheirnever-endingconfidencethatIwouldeventuallyfinishandgetareal
job.Ithankmyfather,TonyVulinec,withlove,foralifetimeofsupport.Thanksare
alsoduePetteBlanchard,JulieCandela,AlfonsoDiaz,andJoannaLambertfor
continualfriendshipandencouragement(wewillsurvive).Finally,withoutthehelp
andsupportofmyfieldassistant,packer,monkey-spotter,andentertainment
committee,myhusband,DaveMellow,thisprojectwouldhavediedalonelydeathin
Rondonia.
TABLEOFCONTENTS
page
ACKNOWLEDGMENTS iii
ABSTRACT vii
INTRODUCTION 1
EvolutionofDispersalCharacteristicsofSeeds 3
OverviewofSeedDispersal 5
CommunityEcologyandSeedDispersal 8
EcologyofDungBeetles 9
DungBeetlesasSeedDispersers 13
BackgroundonMonkeysasSeedDispersers 16
DungBeetlesandDeforestation 25
ForestRegenerationandSeedDispersal 27
Objectives 28
METHODS 31
StudySites 31
Surveys 34
SeedBurialExperiments 38
RESULTS 40
BeetleSurveys 40
MonkeyCensuses 41
MonkeyandBeetleComparisons 42
BeetlesandSeedBurial 42
v
CommunityAnalysis 47
DISCUSSION 88
APPENDIX1.BEETLESPECIESCOLLECTED 98
APPENDIX2.MONKEYOBSERVATIONS 99
LITERATURECITED 102
BIOGRAPHICALSKETCH 116
AbstractofDissertationPresentedtotheGraduateSchool
oftheUniversityofFloridainPartialFulfillmentofthe
RequirementsfortheDegreeofDoctorofPhilosophy
DUNGBEETLES,MONKEYS,ANADMASEZEODNDISPERSALINTHEBRAZILIAN
By
KevinaVulinec
December1999
Chairman:Dr.JohnSivinski
MajorDepartment:EntomologyandNematology
Tropicalrainforesttreeshaveevolvedstrategiestomoveseedsawayfromthe
parentplant.Thesestrategiesarethoughttoreducetransmissionofpredatorsand
fungaldiseasesfromparenttooffspring.Oneofthemostcommonstrategiestomove
seedsisthroughfruitcarriedinvertebrategutsanddefecatedlater.Seedsembeddedin
dunganddepositedontheforestfloorarevulnerabletoseedpredationbyrodents
unlessburiedbydungbeetles.Inthisproject,Iexplorethedynamicsofdungbeetle-
monkey-seedinteractionsandhowthisprocessmaycontributetoforestregeneration,
especiallyinsecondarygrowthanddisturbedhabitat.Workwasdoneatthreesiteson
theAmazonRiverinBrazil:Esta<;aoFerreiraPennainParaandReservaAdolfoDucke
inAmazonas,andprivatelandnearCacaulandia,Rondonia.Ideterminedthatdifferent
speciesofdungbeetleshavevaryingefficienciesatseedburial,andbeetlespecieswere
rankedintoseedburialguildsbasedonscoresfromaprincipalcomponentanalysis.
Thepotentialforseedstobeburiedisdependentonthedungbeetleandmonkey
communitiesateachsite.Communitiesamonghabitatswithinthesamesitealso
differ:clear-cutareasharboraverylowbiomassofdungbeetles,andthespeciesare
differentthaneitherprimaryforestorsecondarygrowth.Secondarygrowthcontainsa
subsetofthesamespeciesfoundinprimaryforest,butlowerinspeciesrichnessand
abundance.Correspondenceanalysisofhabitatsandseedburialguildssuggeststhat
effectiveseeddispersalandburialinsecondarygrowthdependsontheamountof
disturbanceofthathabitat.Somemanagementrecommendationsaremadethatmay
encouragemonkeyandbeetleseeddisperserstocolonizedisturbedareasandcontribute
toforestregeneration.
UNIVERSITYOFFLORIDA
1999
INTRODUCTION
Rainforestsaredefinedandstructuredbytheirtrees.Theseforestsarealso
dynamic;gapsarecreatedbytreefalls,allowinglighttolerantspeciestogrow,andgaps
arefilledinsuccessionally,becomingprimaryforestagain(Martinez-Ramos&
Alvarez-Buylla1995;Brokaw1986,1985).Regenerationintropicalforestsis
dependentonseeddispersal,mostlyaccomplishedbyvertebrates.Althoughdispersal
canbebywind,water,orotherfactors,intheNeotropics,45-90%ofcanopytreesand
almost100%ofshrubsandsubcanopytreeshavefruitadaptedforanimaldispersal
(Terborgh1983;Howe&Smallwood1982;McKey1975).InNeotropicalwet
forests,only10%oftreesaredispersedbywind;incontrast,21%oftreesintemperate
forestshavewinddispersedseeds(Dirzo&Domfnguez1986).IntheNeotropical
rainforests,monkeysareoneoftheprimarydispersersoftreeseeds,swallowingseeds
wholeatthefruitingtree,anddefecatingthemintactadistanceawayfromtheparent
tree(Emmons1990;Estrada&Fleming1986;Janson1983).Primatesareestimated
tobebetween25-40%offrugivorebiomassintropicalforests(Chapman1995;
Terborgh1983;Eisenberg&Thorington1973).Nevertheless,morethan90%of
seedsdispersedbymonkeysmaybedestroyedbyrodents(Estrada&Coates-Estrada
1991).Secondarydispersalandburialbydungbeetlesmayproviderefugiaforseeds
fromrodentpredationandbeanimportantforceinrainforestregeneration.Previous
workhasemphasizedthepotentialroleoftheseinsectsindispersalandseedburial
1
2
(Andresen1999,1994;Feer1999;Estrada&Coates-Estrada1991;Howard&Zanoni
1989)andingermination(Shepherd&Chapman1998).
Dungbeetlesplayintegralrolesintropicalecosystemsasdecomposers,nutrient
recyclers,andseeddispersers.Perturbationsoftheenvironmentchangedungbeetle
communitycompositionand,often,decreasediversity(Vulinec,inpress;Halffteret
al.1992;Klein1989;Moron1987;Howden&Nealis1975).Ascattleranching,
logging,andconcomitantdeforestationincreaseinthetropics(anannualmean
deforestationrateof0.8%between1980and1990;WorldResourcesInstitute1994),
manyspeciesofdungbeetlesthatareadaptedtorainforestconditionsmayvanish.
Notonlywouldextinctionofthisbeetlefaunaaffectbiodiversity,buttheimpactofits
lossonsoilstructure,nutrients,predatoryphoreticmitesandnematodes,andforest
regenerationisunknown.
Recently,muchattentionhasfocusedontropicalforestregenerationand
reclamation(Lauranceetal.1997;Wunderle1997;Laurance1991),particularlyin
placesthathavebeendeforestedforcenturies,suchasareasintheNortheastofBrazil
(Uhletal.1997).Insomecases,abandonedpasturesandplantationsmayregenerate
backtotheoriginalforest,ifenoughintactrainforestisleftinthesurroundingarea,and
ifuseofthedegradedareawaslightormoderate,e.g.notbulldozed(Buschbacheret
al.1992). However,notonlymusttherebeintactforestleft,butthefaunainvolvedin
ecosystemfunctionsalsomustbepreserved,includingthepollinatorsanddispersers
(Pannell1989).
Myresearchhastwosetsofobjectives;(1)delineatethecharactersthatmake
particularspeciesofdungbeetlesgoodseeddispersalagents(dispersaldefinedaseither
horizontalmovementorburial),establishanindexofseeddispersalabilities,andrank
eachspeciesintermsofrelativequalityasaseeddisperser,and(2)examinewhether