threats to native aquatic insect biodiversity in hawai'i - ScholarSpace

212 Pages·2008·8.59 MB·English

THREATSTO NATIVEAQUATICINSECTBIODIVERSITYINHAWAI'IAND THEPACIFIC,
ANDCHALLENGES INTHEIRCONSERVATION
ADISSERTATIONSUBMITTEDTOTHEGRADUATEDIVISIONOFTHE
UNIVERSITYOFHAWAI'IINPARTIALFULFILLMENTOFTHE
REQUIREMENTS FORTHEDEGREEOF
DOCTOROFPHILOSOPHY
IN
ENTOMOLOGY
AUGUST 2005
By
RonaldA. Englund
DissertationCommittee:
MarkWright, Chairperson
DanRubinoff
NealEvenhuis
DanPolhemus
AndrewTaylor
TABLEOFCONTENTS
ACKNOWLEDGEMENTS , ii
ABSTRACT iii
LISTOFTABLES vi
LIST OFFIGURES viii
CHAPTER 1.THEIMPACTS OFINTRODUCEDPOECILIIDFISHANDODONATAONTHE
ENDEMIC MEGALAGRION(ODONATA)DAMSELFLIES OF0'AHUISLAND,HAWAI'I 1
CHAPTER2: EVALUATINGTHEEFFECTS OFINTRODUCEDRAINBOWTROUT(Oncorhynchus
mykiss) ONNATIVESTREAMINSECTS ONKAUA'IISLAND,HAWAI'I 40
CHAPTER3. LONG-TERMMONITORINGOFONEOFTHEMOSTRESTRICTED INSECT
POPULATIONSINTHEUNITEDSTATES, Megalagrion xanthomelasSelys-Longchamps, 1876,AT
TRIPLERARMYMEDICALCENTER, O'AHU,HAWAI'I... 76
CHAPTER4.THELOSS OFNATIVEBIODIVERSITYANDCONTINUINGNONINDIGENOUS
SPECIESINTRODUCTIONSINFRESHWATER,ESTUARINE, AND WETLANDCOMMUNITIES
OFPEARLHARBOR,O'AHU,HAWAIIANISLANDS 91
CHAPTER5. FLOWRESTORATIONAND PERSISTENCEOFINTRODUCED SPECIES IN
WAlKELESTREAM,0'AHU 125
CHAPTER6: INVASIVESPECIESTHREATS TONATIVEAQUATICINSECTAND ARTHROPOD
BIODIVERSITYINHAWAI'I,THEPACIFICANDOTHERRELEVANTAREAS WITHDISCUSSION
OFCONSERVATIONMEASURES 143
ACKNOWLEDGEMENTS
Iwouldliketo thankthemanypeoplethathavemadethis dissertationpossible. Iespeciallywould liketo
extendmythanksandwarmestgratitudetomyadvisorMarkWright, whosesenseofhumorandkeen
intellectmadethis process as enjoyableas itcan be. Mycommittee,consistingofDanRubinoff, Neal
Evenhuis,DanPolhemusandAndrewTaylorprovidedvaluableinsightsandadvicethroughout. Isincerely
acknowledgeandappreciatethe effortsofmyentirecommitteethroughoutmytimeattheUniversityof
Hawai'iatManoa.Iamalsodeeply appreciativeofNealEvenhuisandAllenAllisonfortheir
encouragement,andallowingmetheflexibility topursueaDoctoratewhile beingemployedatthe Bishop
Museum.Ihavegreatlyenjoyedthescientificandcultural 'ohanaattheBishopMuseumthatalways
providedanidealresearchandworkingatmosphere. RobCowieandFrankHowarthoftheBishopMuseum
alsoprovidedvaluablereviewsandadviceformanyofthesechapters. BishopMuseumlibrariansPatti
BelcherandB.J.Shortwerealwayshelpfulintrackingdownthemanyobscurereferences.Severalkey
organizationsprovided thesupportthatallowedmyresearchtotakeplace,andIthankthefollowing
organizationsthatfundedthisresearch: BishopMuseum, HawaiiDivisionofAquaticResources,Nature
a
Conservancy,SmithsonianInstitution, andtheDelegation laRecherchePolynesiefran<;aise.
Peopletoonumeroustomentionassistedmeinvariousaspectsofthefieldworkrequiredforthis wide
rangingdissertation, andIgreatlyappreciatehelpfromDavidPreston,BetsyGagne, DanPolhemus,Jean
Yves Meyer, BenoITFontaine, OlivierGargominy,TinaLau,StephanieLoo, BrianNaeole, Alison
Sherwood,andSteveJordan. SpecialthanksgoestotheHawaiiDivisionofAquaticResources crew
includingBobNishimoto,GlennHigashi,DarrellKuamo'o, JohnKahiapo, SkippyHau, BillPuleloa, and
MikeYamamoto. BillDevickandBobNishimotowerealsoinstrumentalinencouragingandfundingmuch
ofthisresearchaswell. LaVonneFurtadoprovidedconsistentmoralsupportduringthecrucialfinal stages
ofthisjourney.Iamalsoprivilegedtohaveincrediblysupportiveparents andawonderfulfamily, without
whomIwouldhaveneverattemptedthis work. Iwouldliketodedicatethis dissertationtomywonderful
parents,StanleyandMarjorieEnglund.
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ABSTRACT
AlthoughthedeclineinnumbersanddiversityandthreattonativeinsectsintheHawaiianIslandsis widely
recognizedbyfield scientiststherehasbeenlittleprogressineitherdocumentingtherealdeclineofnative
species,orindemonstratingspecificcausesoftheoveralldeclineofthesespecies. Additionally,few
conservationactions toeitherrestorepopulationsormitigateactualthreatstonativearthropodshavebeen
mentionedintheliterature.Thefollowing chaptersexamineseveralassessmentsofrelevantaquaticsystems
andthenativeaquaticinsectsdwellingwithin,wheretherehaseitherbeenaperceivedorrealdeclineofthese
nativeHawaiianaquaticarthropodsbecauseofthreatsfrom invasiveorintroducedspecies.
Thelargeadaptiveradiationoftheendemicnativedamselflies(Coenagrionidae: Megalagrion) inHawai'ihas
receivedconsiderableattentionandstudysinceatleastthe 1880s.EndemicMegalagrionareinmanyways
reflectiveofagreatlossbecausetheyarelargelynowfound inremoteupperheadwaterareasofstreams,yet
theyalsorepresentthehopeofpreservinghighlydiversefreshwaterecosystemsfoundthroughoutthe
Hawaiianarchipelago.Thefirsttwochaptersofthisdissertationexaminetheimpactsoftwodifferingtaxa
ofintroducedfishonHawaiianMegalagrion, Poeciliidae(livebearersormosquitofishfamily) and
Salmonidae(trout).Theeffectsofeachfish speciesonnativeaquaticinsectsdependedmainlyonthe
invasivestatusofeachgroup; forexample,Chapter1(Englund 1999)examinestheimpactsofintroduced
poeciliidsonnativedamselflies. Damselflieswerecompletelyeliminatedontheislandof0'ahuwherever
speciesinthehighly invasivemosquitofishfamily werefound, andonlyremnantpopulationswerefound in
highelevationslackingintroducedfish. Chapter2(EnglundandPolhemus2001)examinestheimpacts of
thenon-invasiverainbowtrout(OncorhynchusclarkI) onMegalagriondamselflies. Damselfliesandallother
nativeaquaticinsectswerenotfoundtobeharmedbytroutintheuppermostelevationsofKaua'istreams
wheretroutreproducenaturally, andevenhadmorerobustpopulationsthaninsomenearbynon-trout
containingstreams.Thelackofimpactsonnativedamselfliesbyalarge,generalistpredatorsuchas
rainbowtroutpointedoutaseemingparadox.Whereas thesmallbutubiquitousmosquitofishappearsto
havecompletelydevastatednativeaquaticfaunawhereverithasbeenintroducedoutsideofitsnaturalrange,
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trout,becauseoftheirrestrictedrange andsmallerpopulationsizeshavehadminimal,ifanyimpactson
nativeinvertebratesinHawai'i.
Becauseintroducedfish specieshavecausedeithertheextinctionorsevererangecontractionsofMegalagrion
damselfliesinHawai'i,long-termmonitoringoftheremnantpopulationshasbecomenecessarytopreserve
theseremainingpopulations. Chapter3(Englund2001)providesacasestudyinboththemonitoringand
preservationofaremnantO'ahudamselflypopulationnowfound inonly95moffishless streamatthe
TripIerArmyMedicalCenter. Chapter3alsoprovidesseveralharrowingexamplesofhowthisspecieswas
nearlybeeneliminatedinthepast10years throughaccidentsandmismanagement. Notonlyaretheendemic
Megalagrionnowmissingfrom alllowlandareasofO'ahu(withtheexceptionoftheTripIerpopulation),
lowlandaquaticinsectdiversitythroughoutO'ahuisataremnantstatus,andbiodiversitysurveysfornative
aquaticinsectsinthePearlHarborwatershedsinChapter4(Englund2002)indicatedanearabsenceof
nativeaquaticinsectsinthesefreshwaterhabitats.LowerPearlHarborwatershedsweredocumentedtohave
lostmanynativeaquaticinsecttaxasuchas allnativeHeteroptera,damselflies,Coleoptera,andmany
Dipteraspecies,whileintroducedinsectspecieswereabundant.
Avarietyofconservationmeasureshavebeensuggestedtoeitherrestoreormaintainthecurrentlevelsof
freshwaterbiodiversityinHawai'i.InChapter5(EnglundandFilbert1999),thecaseofsignificantly
increasingandrestoringstreamflow inaformerlydivertedstreamwasexaminedtodeterminewhetherthis
factoralonewouldleadtoarestorationofnativeaquaticspecies.Itwasfoundthatmerelyincreasingstream
flow byitselfwasnotenoughtoridthestreamofanyalienaquaticspecies,infact, severalnew
nonindigenousaquaticspeciesbecameestablishedafterstreamflows wereincreased.TheresultsofChapter
5confirmthatanintegrated,balancedandpossiblydrasticapproachwillberequiredtomaintainandpreserve
Hawai'i'snativeaquaticinsectfauna. Awide-varietyofconservationmeasuresintheHawaiianarchipelago
willbeneededtomaintaincurrentbiodiversitylevels,andalsohopefullyrestorenativefreshwater
biodiversityinselectedareas.
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ToputtheHawai'iproblemintoperspective, abriefreviewoftheimpactsofinvasivespeciesonnative
insectsinothertropicalareas isprovidedinChapter6.Thisreviewchapteralsoprovides asynthesisofthe
problemfacingHawaiianfreshwaterinsectsandotherterrestrialarthropods inHawai'iandelsewheredueto
invasivespecies,andhowtheHawaiiancasestudyofinvasivespeciesimpactshasmanyparallelsto other
vulnerablebiotas.Finally,drawingonamixedrecordofpastmistakesandsuccessesinHawai'iand
elsewhere,somepotentialpracticalconservationmeasuresintendedtopreserveandrestoreendemicisland
aquaticinsectsareprovidedinChapter6.
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LISTOFTABLES
Table1.1.ExtinctionsofMegalagrionspeciesinsurveyed0'ahuaquatichabitatssince 1936 8
Table 1.2.RemnantnativeMegalagrion speciesfound inO'ahustreams,tributariesinparentheses,and
relativeabundanceinstreamareascontainingnativedamselflies, (rare(R)=<3individualscollectedor
observed); (moderatelycommon(C)=<:3individualscollectedorobserved) 9
Table 1.3.BiogeographicstatusandHawaiianIslanddistributionofaquaticMegalagrion andintroduced
OdonataspeciesfoundonO'ahu 11
Table2.1. AquaticinsectspeciesandnativeorintroducedstatuscollectedateachKaua'istream 50
Table2.2.Totalnumberofaquaticspeciescollectedduringbenthic,drift, andaerial(general)collections
duringthisstudy 51
Table2.3PresenceorabsenceinsurveyedK6ke'eStateParkstreamsofnaturallyreproducingandstOcked
rainbowtroutandnativeMegalagriondamselflies 57
Table2.4.Geographicoriginandterrestrialoraquaticstatusofpreyitemsfound in80K6ke'etrout
stomachs, 1997-1999 60
Table2.5. Summarynumbersandpercentfrequency ofnativepreyitemsofspecialconcerncollectedin
rainbowtroutstomachsduringthis study,comparedtothenumberoftaxacollectedperstream 61
Table4.1. Summaryofthenativeornonindigenousstatusandtotalnumber(percent)ofaquaticspecies
found inPearlHarborestuarinehabitats 98
Table4.2. Geographicsource(yearofintroduction)andknown (orprobablyknown)modeofintroductionof
nonindigenousspeciesofaquaticmacrofaunafoundinPearlHarborstreamsandestuaries 107
Table5.1.Therangeandmeanwatervelocities(±standarderror)recordedintransectsdownstreamof
WaikeleSprings 131
Table5.2.Introducedandnativespeciesfound inWaikeleStream,Oahuin 1993and 1997-1998from 250
maboveWaikeleSpringsdownstreamtoconcreteweir. OahuintroductiondatesfromBeardsley
(1980), Devick(1991a), Cowie(1995), Polhemus & Asquith(1996), Randall(1996), Cowie (1998).
....................................................................................................................................132
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Table6.1. ExtinctionstatusofnativeinsecttaxaintheHawaiianIslands thathaverecentlyhadtheir
conservationstatusexamined,to lowesttaxonomicresolution 149
Table6.2.SuccessfullyeradicatedinvasiveanimalspeciesintheHawaiianIslands 161
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LIST OFFIGURES
Figure 1.1.Limnologicaldivisions onO'ahudefinedforthepurposesofthis study 5
Figure 1.2.Statusofstreamandwetlanddwellingdamselfliesontheislandof0'ahu. E=Extincton0'ahu
.......................................................................................................................................8
Figure 1.3.ElevationaldistributionforHawaiianMegalagriondamselfliesandintroducedpoeciliidfish for
streamsenteringKane'oheBay,O'ahu 12
Figure 1.4.ElevationaldistributionforHawaiianMegalagriondamselfliesandintroducedpoeciliidfishfor
streamsenteringnorthernwindwardO'ahu 13
Figure 1.5.ElevationaldistributionfortheHawaiianMegalagriondamselfliesandintroducedpoeciliidfish
forstreamsenteringPearlHarborandleewardO'ahu 14
Figure 1.6.ElevationaldistributionforintroducedIschnuraramburiiandIschnurapositadamselfliesand
introducedpoeciliidfishforselectedKane'oheBayandPearlHarborstreams,O'ahu 18
Figure2.1. StudyareaofsampledK6ke'eStateParkStreams,Kaua'iIsland,Hawai'i 45
Figure2.2SummaryofaquaticspeciescollectedinK6ke'eStateParkstreamsfromallsamplingmethods
combined(generalsampling,Malaisetraps, drift,benthicsamples) 52
Figure2.3. Summaryofallinsectspeciescollectedfromrainbowtroutstomachs(n=80) andtheir
terrestrialoraquatic,andnativeorintroducedstatusinK6ke'eStateParkStreams 52
Figure 2.4. Meandensity by streamforthetwomostimportantconstituentsofbenthic (Surber) samples,
thecaddisfly C. pettitiandmidge C. bicinctus 53
Figure2.5. SummarygraphofnumberofaquaticspeciesinKaua'iStreamsandthepresenceorabsenceof
naturallyreproducingtroutineachstream;Lumaha'iandHanaleihaveneverbeenstockedwithtrout.
..................................................................................................................................... 53
Figure2.6. ThesixnumericallymostabundantaquaticinsecttaxacapturedindriftsamplestakeninK6ke'e
stateparkstreams 58
Figure3.1. MapofO'ahu,Hawai'ishowinglocationsofcurrentandhistoricrecordsfor Megalagrion
xanthomelas(fromEvenhuis eta1., 1995) 78
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Figure 3.2. TAMCMitigationpondspriorto drainage, February 2000 79
Figure3.3. Megalagrion xanthomelascapturesatTAMC stream,May 1997-June2000 82
Figure 3.4. Megalagrion xanthomelascapturesatTAMCmitigationpondsfrom May 1997-February2000.
..................................................................................................................................... 83
Figure 3.5. Oviposition scars on waterlilies atthe TAMC mitigationpondsJuly 1997-February2000.. 84
Figure4.1. MapofPearlHarborwithsamplinglocations 95
Figure4.2. Numberofspeciesbystreamandnativeornonindigenousstatusforcombinedaquaticfauna
found inestuarineregionsofPearlHarbor 98
Figure4.3. Nativeornonindigenousstatusoffish speciesandtotalnumbersfound atdifferentsalinity
levelsinPearlHarborestuaries 101
Figure4.4. Nativeornonindigenousstatusofaquaticinsectsatvaryingelevations onO'ahu: upperHalawa
datafromPolhemus(1994),upperWaikeledatafromEnglund(1993) 112
Figure5.1. WaikeleStreamstudyarea 128
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