threats to native aquatic insect biodiversity in hawai'i and the pacific, and challenges in their

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.
11
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,
iii
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
viii
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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