Biogeography of the Indo-Australian Archipelago - SE Asia

24 Pages·2011·0.77 MB·English

ES42CH10-Lohman ARI 26September2011 14:33
Biogeography of the
Indo-Australian Archipelago
David J. Lohman,1,∗ Mark de Bruyn,2,∗ Timothy Page,3
Kristina von Rintelen,4 Robert Hall,5 Peter K.L. Ng,6
Hsi-Te Shih,7 Gary R. Carvalho,2
and Thomas von Rintelen4
1DepartmentofBiology,TheCityCollegeofNewYork,TheCityUniversityofNewYork,
g NewYork,NY10031;email:[email protected]
or
s. 2SchoolofBiologicalSciences,BangorUniversity,Bangor,GwyneddLL572UW
w
e UnitedKingdom;email:[email protected],[email protected]
vi
ualre e3Amuasitl:rapleiannguRiinvteimrs@Inhsotittmutaeil,.GcormiffithUniversity,Nathan,Queensland4111,Australia;
n
ww.anonly. H4MuumsbeuomldtfuU¨rnNivaetrusirtkyuBnderel—in,L1e0ib1n1i5zBInesrtliintu,tGeeformrRaneyse;aermchaiol:[email protected],he
we [email protected]
d from onal us L5Soonudtohne,asEtgAhsaimaR,SesuerarrecyhTGWro2u0p0,EDXep,aUrtnmiteendtKoifnEgadrotmh;Secmienaicle:sr,[email protected]
nloadeor pers N6DaetipoanratmlUenntivoefrsBitioyloofgiScianlgSacpioenrec,eSsianngdapRoarfefle1s17M5u4s6e;uemmaoifl:[email protected],
Dow11. F e7Dmeapila:[email protected],dNu.atwtionalChungHsingUniversity,Taichung402,Taiwan;
6. 3/
22
05-2n 11/
2o
42:all Annu.Rev.Ecol.Evol.Syst.2011.42:205–26 Keywords
1.H
ol. Syst. 201Prof Robert FATSyiuhrsgtseetumApstanut1nbi5culsi,asil2hsR0eod1env1oliiennwleinoafetEeacscooalolsgRyyes,.vEainevwnoluuiantilorAnevd,ivaeanwndsc.eorogn pWAhbayslllotargcaeecnatetics,phylogeography,SoutheastAsia,Thai-MalayPeninsula,
Evby
col. T10h.1is1a4r6t/icalnen’sudreovi:-ecolsys-102710-145001 The extraordinary species richness and endemism of the Indo-Australian
E Archipelago(IAA)existsinoneofthemostgeologicallydynamicregionsof
ev. Copyright(cid:2)c 2011byAnnualReviews. theplanet.Theprovenanceofitsbiotahasbeendebated,particularlyinthe
u. R Allrightsreserved areaknownasWallacea.Applicationofmoleculargeneticapproachesanda
n
An 1543-592X/11/1201-0205$20.00 betterunderstandingoftheregion’scomplexgeologyhavestimulatedmuch
∗Jointfirstauthors. recentbiogeographicworkintheIAA.Wereviewmolecularphylogenetic
andphylogeographicstudiesinlightofcurrentgeologicalevidence.Present
distributionpatternsofspecieshavebeenshapedlargelybypre-Pleistocene
dispersalandvicarianceevents,whereasmorerecentchangesintheconnec-
tivityofislandswithintheArchipelagohaveinfluencedthepartitioningof
intraspecificvariation.Manygeneticstudieshaveuncoveredcrypticspecies
with restricted distributions. We discuss the conservation significance of
the region and highlight the need for cross-taxon comparative studies us-
ingnewlydevelopedanalyticalapproacheswellsuitedtothechallengesof
historicalinferenceinthisregion.
205
ES42CH10-Lohman ARI 26September2011 14:33
INTRODUCTION
Vicariance: TheIndo-AustralianArchipelago(IAA),alsoknownasMalesiaortheMalayArchipelago,isthe
divisionofaformerly most geographically complex tropical region on Earth. It comprises more than 20,000 islands
continuously straddlingtheequatorinSoutheastAsia,andincludesBrunei,EastTimor,Indonesia,Malaysia,
distributedpopulation
NewGuinea,Philippines,Singapore,andpeninsularThailand(Figure1).Overthepast50My,
orspeciesduetothe
thegeographyofthisregionhaschangedconsiderably(Figure2),andancientvicarianceevents
formationofabarrier
havegivenrisetoremarkablepatternsinthedistributionofhighertaxa.Morerecently,risingand
Dispersal: movement
fallingsealevelsduringthePleistocenecausedislandsontheSundaShelftorepeatedlysunderand
oforganismsacrossa
barrier fusewitheachotherand/orthemainlandastheseafloorwasexposedandthensubmerged.Land
areawasconsiderablygreaterduringperiodsoflowsealevels,whichfacilitatedterrestrialdispersal
IAA: Indo-Australian
Archipelago betweenislandsthatarecurrentlyseparated.IncontrasttotheHolarctic,wherecurrentorganismal
distributionsfrequentlyreflectrangeexpansionsfromPleistocenerefugia,distributionsintheIAA
g
or
s.
w
evie Vietnam China Taiwan Wallace’s Line Brunei
alr Myanmar Huxley’s Line East Timor
u
nn Laos Lydekker’s Line Indonesia
ww.aonly. Hainan Luzon MSinalgaaypsioare
we
m us
d froonal ThTahilaanildand Philippines
nloadeor pers Cambodia
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205-226. Doon 11/23/11. Iosft hKmraus South PalawaCnagayan Arc SSuelau Mindanao
ol. Syst. 2011.42:Prof Robert Hall Strait of Malacca peMTnKhainaalansi-yuglaar-PatStSaunhin leindlefa China Sea KinMabt.alu CeSleebaes P HhilailpmpianhHeearsl-am aAhrecra
Annu. Rev. Ecol. Evby Sumatra BKearliimtuatna gstraitGSurenadtBaK(eIoansrlrdinmoenaoenstiaan) Makassar strait SulaweTseirnBaatenda SeaSeram Aru (InPdaopnNueaseiwa) EGquuinaetoar
Sunda strait Bandung Java Sea Wallacea
Java Bali Lombok
Flores
N Sahul
bok strait SumbaLesser SundasT imor Ban da Arc Shelf GPNuaipenwueaa
m
o
L
Figure1
MapoftheIndo-AustralianArchipelago(IAA)indicatingcontemporarylandmasses,straits,seas,arcs,andfaunallines.Majorislands
arelabeled;differentcountriesintheIAAareindicatedbycolor.Redororangebordersaroundanislandindicatemembershipinthe
GreaterorLesserSundas,respectively.
206 Lohmanetal.
ES42CH10-Lohman ARI 26September2011 14:33
100˚E 110˚E 120˚E 130˚E 100˚E 110˚E 120˚E 130˚E
a b
Volcanoes
Highlands
Land
Lakes
Shallow sea
0˚ Carbonate 0˚
platforms
Deep sea
Trenches
10˚S 10˚S
g
or
s. 60 Mya 40 Mya
w
e Paleocene Late Eocene
vi 20˚S 20˚S
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u
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nloadeor pers
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6. 3/ 10˚S 10˚S
22
05-2n 11/
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42:all 30 Mya 20 Mya
ol. Syst. 2011.Prof Robert H 20˚S Middle Oligocene e Early Miocene f 20˚S
Evby
ol.
c
E
v. 0˚ 0˚
e
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n
A
10˚S 10˚S
10 Mya 5 Mya
Late Miocene Early Pliocene
20˚S 20˚S
100˚E 110˚E 120˚E 130˚E 100˚E 110˚E 120˚E 130˚E
Figure2
SixCenozoicreconstructionsoflandandseaintheIndo-AustralianArchipelago.
www.annualreviews.org • Indo-AustralianBiogeography 207
ES42CH10-Lohman ARI 26September2011 14:33
arecurrentlyrefugial(Cannonetal.2009).DuringthePleistocene,theSundaShelfhadhalfthe
coastlineandtwicethelandareaastoday;thisexposedshelfisknownas“Sundaland”(Woodruff
2010). The complex history of the IAA has given rise to a diverse and highly endemic biota.
Sundaland: a
Although it occupies just 4% of the planet’s land area, the IAA is home to nearly one-quarter
terrestrialextensionof
mainlandSoutheast ofallterrestrialspeciesandthemostspecies-richcoralreefsintheworld(Corlett2009).Four
Asiaformedduring biodiversity hotspots are at least partly in the IAA: Indo-Burma, Philippines, Sundaland, and
periodswhenlowsea Wallacea(Myersetal.2000),butthisincrediblediversityisundersevereanthropogenicthreat.
levelsexposedseabeds
Islandsandarchipelagoshavelongbeenconsiderednaturallaboratoriesforthestudyofevolu-
betweentheMalay
tion.WhiletheGalapagosIslandsstimulatedCharlesDarwin’sseminalwork,theIAAwasAlfred
Peninsula,Java,
Sumatra,andBorneo Russel Wallace’s muse. He famously sent Darwin a manuscript from Ternate, in what is now
Indonesia, in which he articulated his concept of evolution by natural selection (Darwin &
Terrane: afragment
ofcrustboundedby Wallace1858),stimulatingDarwintocompleteOntheOriginofSpecies(Darwin1859).Observa-
g faultswithadistinctive tionsintheIAAalsomotivatedWallacetodevelopmanyofhisideasontherelationshipbetween
s.or stratigraphyand geologicalhistoryandanimaldistributions,andtheregionshouldthereforeberegardedasthe
w
vie history birthplaceofmodernbiogeography.UnliketheAzoresandtheCanary,Galapagos,andHawaiian
e
alr islands,whereallislandsaretrulyoceanicandarosefromtheoceanfloorthroughvolcanism,the
u
n islands of the IAA are of more varied origin, comprising pieces of continental crust (terranes),
n
www.ae only. otwceoainsilcanisdlsanadttsa,inaneddtlhaneidrmparsesseesntofcocnofimgpuorsaittieonoraigftienr,sseupcahraatseStuerlarawneessicaonldlidNeedw,pGotueinnteiaa.llyTwheitshe
d from onal us anyRreecseidnetnwtobrikotina.geology,palynology,paleoclimatology,andmolecularsystematicshasadvanced
nloadeor pers hstiustdoyriicnalthreecIoAnAs;trruecvtiieownroefcethnetermegpioirnic’saluandiqvaunecheisstinorgye.oWloegys,upmhmylaorgizeeneptricesv,ioaunsdbainoigmeaolgprahpyhloic-
wF
Do11. geography;andsuggestfuturedirectionsforbiodiversityresearchandconservation.
6. 3/
22
05-2n 11/ HISTORYOFBIOGEOGRAPHICSTUDY
2o
42:all INTHEINDO-AUSTRALIANARCHIPELAGO
1.H
Evol. Syst. 201by Prof Robert Th“(eWSoUaultlnhaciAeqm1u8ee6rn0ic,eapsa.sn1d7o4Af).fWricaa,llsaepcaer’asteLdibnyetheAtlantic,donotdiffersowidelyasAsiaandAustralia”
ol. Wallace’sLinedemarcatesthemostabruptfaunaltransitionintheworld.Toaseasonednatural-
c
E
v. istlikeWallace,thisuniquejuxtapositionofdramaticallydifferentfaunas,firstnotedbyMu¨ller
e
R (1846), was obvious, was anomalous, and begged explanation; so it is perhaps no accident that
nu. biogeographicstudyeffectivelybeganintheIAA.Therangelimitsofmanyterrestrialtaxaare
n
A coincidentwiththeeasternedgeoftheSundaShelf,andthetaxonomiccompositionsofcommu-
nitiesoneithersidearedistinctlydifferent.Wallaceadvocatedgeologicalexplanationsforthese
biological differences. He suggested, for example, that Bali and Lombok were formerly widely
separatedandhadonlyrecentlymovedtotheirpresentpositions<40kmapart;healsonotedthat
faunaldiscontinuitieswereassociatedwithdeepstraits(Wallace1860).Wallacefirstdescribedthe
Lineinan1858lettertoH.W.Bates(Marchant1916,p.66)beforehemappedtheLine(Wallace
1863)thatwaslatergivenhisnamebyHuxley(1868)andexpoundedupontheseobservationsin
booksontheIAAandbiogeographyingeneral(e.g.,Wallace1869).TheveracityofWallace’s
observationswasdebatedbecausetheexistenceofsuchastarkfaunaldivideseemedimprobable,
andthisspurredintensestudyofdistributionpatternsintheregion(e.g.,Weber1902).
One product of this debate was the designation by Dickerson (1928) of a faunal transition
zone called Wallacea. Although the relevance of this area became controversial (Mayr 1944),
208 Lohmanetal.
ES42CH10-Lohman ARI 26September2011 14:33
usageofthetermhasbecomeentrenchedtorefertothezoneofislandsbetweentheAsianSunda
Shelf and Australian Sahul Shelf—continental shelves that are traced by Wallace’s Line [with
Huxley’smodification(Huxley1868)]inthewestandLydekker’sLine(Lydekker1896)intheeast
(Figure 1). Dickerson’s original concept of Wallacea included the Philippines, but we concur
withmodernusageandconsidertheseislandstobeaseparateentity.
Simpson’s (1977) critical review of Wallace’s and six other faunal lines questioned the im-
portanceofchoosingasinglefaunallineratherthanacknowledgingthatpatternsofcommunity
diversityamongdifferenttaxaaretoovariedtomakeone,universallyapplicabledistinction.Nev-
ertheless, Wallace’s Line has remained a heuristic concept and is still widely cited because it
highlightsthestrikingfaunaldiscontinuitiesobservedinthisregion,evenifthosepatternsarenot
universal.
Intheearly1980s,advancesingeologyandtherecognitionofplatetectonicconceptsallowed
g theformulationofplausiblevicariantmechanismstoexplainthedistributionoftaxaonmultiple
or
s. islands(Whitmore1981).Thesegeologicaladvancescomplementedmethodologicalrefinements
w
vie inphylogeneticsystematicstosupportthenovelhypothesisthatsomeorganismsdispersedwithin
e
alr the region on mobile terranes (Michaux 1996). Much early research, including Wallace’s own
u
n observations,focusedonvertebrates,butinsectsfeaturedprominentlyinthisnewfusionofplate
n
www.ae only. ttehcetIoAnAicsbeannedfictltaeddisetnicosrm(Konuisglhytfr&omHmololorweraeyli1a9b9le0)a.nIdndtehteaillaetdep1l9a9te0ste,cbtioongiecomgroadpehlisc(Hreasella1r9ch96i)n,
d from onal us wThhiecshemmoaddeelsancoiimncmideeddiawteitihmtphaecetxopnlobsiivoegegorogwratphhoicfaml oinletecruplarertpahtiyolnog(eHnaeltlic&saHndolplohwylaoyge1o9g9r8a)-.
nloadeor pers phymadepossiblebyPCRandaffordableDNAsequencingtechnology.
wF
Do11. VicariantVersusDispersalistSchoolsofBiogeography
6. 3/
05-22n 11/2 Sorindciesptheresalaltitserthheaplfroedfothmeinnainnettfeoernctehecxepnlatuinriyn,gbdioisgteroibguratipohnesrssphaanvneindgebmatoerdewthhaenthoenrevliacnardimanacses
2o
42:all (Lomolinoetal.2010).Wallace(1863)espousedavicarianthypothesisinvokingaformerPacific
1.H
ol. Syst. 201Prof Robert clbsitoicronaagtititieosnoneagssnrtla(aeptt.ohegy.ae,,sxaWp1nl9daa3ilRn6la.echTneissoc1edh8pa7(yo16,n9)my.3mVa6n)oicyiunaosrvfioLatknhinetedeePabxhpneilfulaoimpnrpeabtieaniordenooaspfnhtwdiyneWpgroedathnlilseeaptvceieecrarasnalclloiiassmnltadpsncbldeerstnieadalrgryeieoagssbeaanicnnreodrhsaoislsnldyeleadreteepgirnawprIaduAtebeAd-r
ol. Evby asoceanicislandsbecausetheyhavehadnoterrestrialconnectiontoanysurroundinglandsince
c theiremergence(vanOosterzee1997).Consequently,theirbiotaarosepredominantlyviadisper-
E
v. salandnotvicariance.Sulawesiisaspecialcasebecausetheislandwasformedbythecollisionof
e
R
u. differentterranesandsubsequentfragmentationbeginningapproximately15Mya(Figure2d,e).
nn SomeofitscurrentbiotamaythereforehavevicariantoriginsfromSundalandinthewestorNew
A
Guinea/Australiatotheeast(Wilson&Moss1999,butseeHall2001,2011).However,thereis
nowlittledoubtthatthebulkofSulawesi’sfaunaisofAsianorigin,anddispersalhasreplacedland
bridgesasthefavoredexplanationfortheoriginsoftheisland’sbiota(vanOosterzee1997).
GEOLOGICALRECONSTRUCTIONS
OFTHEINDO-AUSTRALIANARCHIPELAGO
CenozoicGeologicalChanges
The network of islands that forms the IAA comprises two continental shelves and numer-
ous smaller terranes. These elements are in a state of continuous flux, and the geography of
the IAA during the Cenozoic was markedly different from today (Figure 2; Supplemental
www.annualreviews.org • Indo-AustralianBiogeography 209
ES42CH10-Lohman ARI 26September2011 14:33
Figure 1, follow the Supplemental Material link from the Annual Reviews home page at
http://www.annualreviews.org). The Philippine islands of Palawan and Luzon, for example,
wereseparatedbyatleast1,300kmduringtheearlyEoceneapproximately50Mya(Hall1996),
Emergent:
buttodayareseparatedbylessthan300km.Asterranesweremovingaroundwhatisnowthe
protrudingabovesea
level SouthChinaSea,theydidnotnecessarilyremainabovesealevel(Hall2001);submergencewould
presumably have extinguished all terrestrial and freshwater life they may have hosted. Recon-
Subduction: a
processinwhichone structingthegeologicalhistoryoftheIAAisessentialforunderstandingcontemporarypatternsof
tectonicplatemoves diversitybecausethelikelihoodofdispersalorvicariancebetweenparticularlandmassesdiffered
underanother atdifferenttimesinthepast.
AtthebeginningoftheCenozoicapproximately65Mya,Sundalandwasacontinentalpromon-
toryatthesouthernendofEurasia(Hall1996).Itwasanemergentterrestrialregionthatcrossed
Supplemental Material
theequator,probablywithamountainousinteriorandriverscarryingsedimentstothecontinental
g margins.DuringthePaleocene–EarlyEocenethermalmaximumapproximately56Mya,thecli-
or
s. matewassimilartoorwarmerandwetterthantoday,butfromapproximately45Myaduringthe
w
vie MiddleEoceneonwardwasprobablymuchmoreseasonalandpossiblydrieruptotheNeogene
e
alr approximately23Mya(Heaney1991,Morley2000).
u
n MajorchangesbeganintheEocene(Hall2002).Indiahadmovedrapidlynorthduringthe
n
www.ae only. CAuresttraacleioauhsatdobcaorlelildyeswepitahraAtesdiafartosmomAenttiamrcetiicna.thItebPeagleaongteonem(oRvoewrlaepyid19ly96n)o.rDthuwrianrgdtfhroismtimape-,
d from onal us pInrodxoinmeasitae,lyca4u5siMngyaw(iHdeasllp2re0a0d2)v.oNlcoarntihswmaradtstuhbedauccttivioenmoafrtghienAaunsdtrpalrioadnupcliantgercehsauimnsedofbiesnlaenadths
nloadeor pers (Jaarvcasa)nsidmtihlaerntoortthhoasremooffthSeulWaweesstiP,aancdificcotnotdinayu.eTdhinetoSuthnedawAesrtcerstnrePtacchiefidcftroojmoinSuthmeaPtrhai,litphprionuegsh–
wF
Do11. HalmaheraArc(Figure 1).Oneofthedeepestandwidestrifts,theMakassarStraitseparating
6. 3/ BorneofromwesternSulawesi(Figure 1),wascreatedbystretchingoftheSundalandmargin,
22
05-2n 11/ thusformingthegeologicalbasisforWallace’sLine.Southwardsubductionoftheproto-South
1.42:2Hall o CMhioincaenSeea(eaxlcseopbtefgoarnthbeenbeoartdherBowrintheow.eSsutenrdnalSaunldawweassi,suwrhriocuhnadpepdebarysstuobhdauvcetiobneeznonaefsauulnttaillotnhge
ol. Syst. 201Prof Robert tBhoerInbneotouhnaednEadraytrhlmyeaMTrhgioainci-)eMnaneadlaapywpaPrsoepnxirimnosbauatleball.yy2m3aMinlyyac(lFoisgeutroes2eadl)e,vtehle,wAiutshtrealleivanatepdlaateremasaidnewcoensttearcnt
Evby with the submerged Sundaland margin near Sulawesi, and the Sunda region began to rotate,
ol. initiallykeepingpacewithAustralia’snorthwardmovement.Fromapproximately20Mya,New
c
v. E Guineabegantoemergefromthesea,probablyassmallislandsalongthenorthernedge,butmost
Re oftheareathatisnowmountainswasshallowsea.Ataboutthesametime,mountainsrosefrom
u. centralBorneotoPalawan.Riversflowingfromthesemountainsbegantoshedlargeamountsof
n
n
A sediment into the onshore and offshore basins around Borneo. The collisions led to closure of
thedeepoceanbarrierbetweenSundalandandAustralia,anincreaseintheareaofshallowseas
throughouttheregion,andsignificantreductioninflowfromthePacifictotheIndianOcean.
Theriseofmountainsandchangesinoceancirculationprobablycontributedtothechangetoa
generallywetterclimateinSundalandfromtheMioceneonward(Morley2000).Despiteuplift
inBorneo,therewasagradualincreaseintheareaofshallowseasandreductioninlandareaon
SundalandduringtheNeogeneuntilthePlioceneapproximately5Mya(Figure 2f).Collision
contributedtoemergenceofmorelandinWallacea,includingintermittentlyemergentislands,
extensivecarbonatereefs,andshallowbuildupsbetweencontinentalAustraliaandSundaland,but
therewasnopermanentlandconnection.
DuringtheLateNeogene,Australiacontinuedtomovenorth,andsubduction-relateddefor-
mationledtothegradualemergenceofSumatraandJavaasmajorlandareasduringthePliocene.
210 Lohmanetal.
ES42CH10-Lohman ARI 26September2011 14:33
FromBorneotoNewGuinea,severalsmalloceanicbasinssubductedatdifferenttimes,leading
toacomplexpatternofupliftandsubsidence,contractionandextension,andthedevelopment
of new deep oceanic basins and volcanic arcs. Over the past 7 million years, crustal melting in
Borneo caused the rise of Mount Kinabalu to its present height of more than 4 km, and deep
crustalprocesses contributedtowidening the area oflower hills surroundingit.The Makassar
Strait remained a deep but narrowing marine barrier east of Borneo as mountains rose rapidly
inSulawesiduringthepastfivemillionyears.Atthesametime,deepbasinsformedbetweenthe
armsofSulawesi(Figure2f).IntheBandaArcregion,subductioneliminatedanold,deepoceanic
embayment,butnewdeepbasinsformed,theAustraliancontinentalmarginextended,andthere
was collision of a young volcanic arc with the Australian margin (Spakman & Hall 2010). As a
result,theislandsoftheBandaArc,notablyTimorandSeram,emergedinthepasttwomillion
yearsfromdepthsofseveralkilometerstoelevationsofmorethanthreekilometers.Atthesame
g time,evenhighermountainsrosetoformtheCentralRangesofNewGuinea,andmostofthat
or
s. islandemergedfromtheocean.NewGuineahasneverbeenclosertotheSundaShelfthanitis
w
vie atpresent,butthetwohavealwaysbeenseparatedbyocean.
e
alr
u
n
www.ane only. QSeuaaletveerlncahrayngGeedorilvoegnicbaylpCohlaarnicgeevsolumechangesmodifiedlandareaovermuchoftheIAA
d from onal us dofurlianngdtahnedQsuhaatlelornwarsyea(sHoannetbhuethSuentdaal.a2n0d09S)a.hItuilssphoeslsviebslebtyoumsiankgeprereasliesntitc-daassyesbsamtheynmtseotrfyaraenads
nloadeor pers ethsteimTahtaeis-MofahlaisytPoreincianlscuhlaan,Sguemsiantrsae,aalnedvenlo.rStuhcehrnreBcoornnsetorutcotwioanrdsitnhfeeSromuatjhoCrrhiivnearsSdearaainndinagmfraojomr
wF
Do11. riversystemflowingeastalongthepresentJavaSeawithadrainagedivideatapproximately3◦Snear
6. 3/ thepresentpositionofBelitung(Molengraaff&Weber1921,Voris2000).Riversflowedtoward
22
05-2n 11/ WallaceafromthenortherninteriorofAustraliaduringperiodsoflowestsealevel(Torgersen
1.42:2Hall o ePtleails.t1o9c8en5)e.gTloacdiaayl,inStuenrdvaallsa,nmduhcahsaohfuitmmida,ytrhoapviecablecelnimcaotoelewritahnsdeadsroienra,lbmuotnesvoeorwnse.tDcounridnigtiothnes
ol. Syst. 201Prof Robert aeKpmipneearabgraelntuotahSnaudvnpedoapsesSirbhslieysltfsemd(Baiilnrldanroeertatshaole.frnn20oS0rut5hm,SMautrmoar,aletwryaes2wt0ee0rrn0e)h.ainDgdhunerinonrogtuhgcehornotoleBrhoarivnneteebore,veaanlnsd,caoppnaplreytdsMboyfoiutchneet,
Evby whereasNewGuineahadextensivemontaneglaciers(Hope2007).
ol. ItisnotpossibletoestimatetheQuaternarydistributionoflandandseainWallaceausingthe
c
v. E sameapproachbecauseofveryrecenttectonicchanges.Thisregionischaracterizedbymountain-
Re ousislandssurroundedbynarrowshelvesandseparatedbybasinsmuchdeeperthan120m—the
u. greatestsealeveldecreasethoughttohaveoccurred.TimorandSumba,forexample,havebeen
n
An risingatratesof1–1.5kmMy−1 sincethemid-Pliocene(Roosmawati&Harris2009),whereas
GorontaloBaybetweentheeastandnortharmsofSulawesiattainedadepthof1–2kmrelatively
recently(Hall2011).RapidverticalchangeslikethislikelyoccurredinotherWallaceanlocales.
AlthoughthepaleogeographyofWallaceaisuncertain,itisclearthatdeepmarineareaspersisted
betweentheSahulandSundashelvesandtherewasnolandconnection.
There are a number of large freshwater lakes, or former lakes, in land areas such as Java,
Sulawesi, and Mindanao that emerged in the Plio-Pleistocene approximately 1.5 Mya, but few
havebeenstudiedtodeterminetheirage.DetailedworknearBandunginJavashowsthatalarge
lake formed 135 kya and disappeared in the past few thousand years (van der Kaars & Dam
1995).Otherlargelakesareintectonicallyorvolcanicallyprecariousareas(e.g.,Matano,Poso
andTowutiinSulawesi,andLanaoinMindanao)and,wheredated,areyoungerthantheBandung
Lake(e.g.,Dametal.2001a).Itisunlikelythatanylakeshavetheagesofseveralmillionyears
www.annualreviews.org • Indo-AustralianBiogeography 211
ES42CH10-Lohman ARI 26September2011 14:33
thataresometimesattributedtothem(e.g.,Tamuntuanetal.2010).Untilthereisevidenceto
thecontrary,all—includingthoselakespostulatedonthesubmergedshelfareas(Sathiamurthy&
Voris2006)—shouldcautiouslybeconsideredasgeologicallyephemeralwithlifetimesofhundreds
ofthousandsofyearsatmost.RecentseismicdataonSulawesi’sLakeTowutisuggestanageof
approximately600ky(J.Russell,personalcommunication).
PALEOCLIMATERECONSTRUCTIONS
Climate:MiocenetoPresent
Whilethechangingconfigurationoflandandseaaffectedthelikelihoodofdispersalaroundthe
IAA,changesinclimateaffectedthetypeandextentofdifferenthabitats.Inferredlandconnections
g betweenformerlyisolatedislandsmaynothavebeenconducivetobioticinterchangeifinterven-
or
s. ing habitats were not suitable. Pollen records and paleoclimatic information are used to infer
w
vie pasthabitats,andancientclimatesareoftenreconstructedthroughmarinesedimentcoresusing
alre Foraminiferaandisotopesofoxygenandcarbon(Zachosetal.2001).MorerecentPleistoceneand
nu Holoceneclimatesareinferredbycombiningglobalpredictionsbasedonthesedatawithregional
n
www.ae only. ddaisttariobnutpioonllsen(M,deiiajatoamrda2n0d03s)e,dmimagennetatricyssutuscdeipestiboifliltaykeofasneddibmogenctosr(eTsa(mDuamntueatnale.t2a0l.0210a)1,0f)a,uannadl
m us landscapefeatures(Hope2007).
d froonal ThenorthwardmovementofAustraliaintheMioceneapproximately15Myaaffectednotonly
nloadeor pers tohceeagneocluorgriecnatlsbauntdaltshoetrheelactliivmeadtiisctrsiebtutitniogn,booftlhanredgaionndaslelyaa(Mndogrlleoyba2l0ly0,0b).yWchaarnmgi,nhgupmaitdtegrlnosboafl
wF
Do11. climatespeakedinthemid-Miocene17–15Mya(Zachosetal.2001).Globalandregionalclimates
6. 3/ slowlybecamecooleranddrier,butremainedrelativelywarmandhumidthroughtothePliocene
22
05-2n 11/ approximately5Mya(Morley2000,Woodruff2010).
2o Theinterplaybetweenthemovementoftectonicplates,oscillationsintheEarth’sorbit,and
1.42:Hall the variable amount of land and sea in the IAA due to sea level change led to consistent and
ol. Syst. 201Prof Robert pspeelapriainoradctioecncgslltiaamcniataltlyeccayhlctaleenrsegd(eWdthuoeroidenxrgutetffnhte20oQ1f0ud)ar.tyeTrlhnaenardry,e(ptDheuaatsmecdhefltaonaolg.din2i0ng0gt1haben)d,tiwmdhriaincignhinahngaddoamfptophiresothuxuirmegeactoSenluytne5dn0at
Evby ofthemonsoons(Hope2007).TheclimateduringmostoftheQuaternarywascharacterizedby
ol. longglacialphases(withtheSundaplainsexposedandacoolanddryclimate),interspersedwith
c
E shortwarmhumidinterglacialperiods,suchasthepresentday(Morley2000,vanderKaars&
v.
e Dam1995).
R
u. Thelastglacialmaximumapproximately18Kyawasamongthemostsevereofthesecycles
n
An (Morley2000),withtemperatures6–9◦Clowerintheuplands,leadingtoexpandingglaciersand
lower tree lines in the New Guinea highlands and other high-elevation areas (Hope 2007). In
contrast,thelowlandsmayhavebeenonly1–2◦Ccooler(Pickettetal.2004).Specificgeographic
features,suchashigher-altitudeislands(Meijaard2003),wouldhaveaffectedlocalclimatesinsome
areas.Byapproximately6Kya,temperatureshadwarmedagain,andtheclimateandgeography
acrosstheregionwasbroadlysimilartothepresentday(Pickettetal.2004),althoughdissimilar
tomostoftheprecedingtwomillionyears(Woodruff2010).
SundalandHabitatReconstructions
ItisuncertainwhethervegetationcoveringtheexposedSundaShelfduringthelastglacialmax-
imumwasdominatedbysavannahorbyevergreenforest.Fossildistributionsandpaleoclimatic
212 Lohmanetal.
ES42CH10-Lohman ARI 26September2011 14:33
reconstructionssuggestthatanareaoflowrainfallextendedfromtheThai-MalayPeninsulato
easternJavaandwascoveredwithseasonalforestorsavannah(Heaney1991).Forrainforesttaxa,
thesehabitatswouldhavebeenasignificantbarriertodispersalbetweenthewest(Sumatraand
theThai-MalayPeninsula)andtheeast(Borneo),butwouldhaveenabledspeciesadaptedtoopen
vegetation,suchasHomoerectus(“JavaMan”),todisperseeasilytoJavafrommainlandAsia(Bird
etal.2005,Morley2000).Pollenrecords,subfossilevidence,andgeneticdatafromvertebrates
supportthissavannahcorridorhypothesis(Figure 3)(Birdetal.2005,Gorogetal.2004,Lim
etal.2011).Incontrast,distributionalandmolecularphylogeographicdataofsomerainforest-
associatedtaxasuggestthatevergreenrainforestswerecontinuouslydistributedacrosstheSunda
Shelf(Birdetal.2005,Cannon&Manos2003).Recently,aspatiallyexplicitvegetationmodel
of the Sunda Shelf incorporating geologic, geographic, and paleoclimatic evidence projected a
corridor of seasonal forest separating Sumatra from Borneo. In some projections, however, an
g east-westbandofevergreenforestconnectingSumatraandBorneobisectedthisnorth-southcor-
or
s. ridor.Thepresenceofthisconnectingcorridorofevergreenforestdependedonparameterization
w
vie ofthemodel(Cannonetal.2009).Furtherphylogeographicworkinthisregionwillrequirethe
e
alr analysisofrapidlyevolvingmarkersanddensesamplingofrainforest-dependenttaxathroughout
u
n Borneo,Java,Sumatra,andtheThai-MalayPeninsulatodeterminewhetherasavannahcorridor
n
ww.aonly. wasapervasivebarriertodispersalacrosstheSundaShelfduringthePleistocene.
we
m us
d froonal SYSTEMATICANDPHYLOGEOGRAPHICPATTERNS
nloadeor pers IWNalTlacHe’Es (I1N85D9)Oe-aArlUiesStTwRriAtinLgIsAfNromARSCouHthIePaEstLAAsiGaOstress similarities between Java and
wF
Do11. Borneo and differences between Borneo and Sulawesi. Similarly, he drew attention to islands
6. 3/ on either side of the Lombok Strait, where faunal limits are “most intimately connected.”
22
05-2n 11/ Wallace (1860) documented birds of five Sundaic genera on Bali but found none on Lombok,
1.42:2Hall o afrnodmloBcaaltie.dWthhrieleesatvrieasnsignegntehraatofnauLnoamsobnokeitthhaetrwseidreecoofmthmeodniviindeSwulearweedsiraamndatMicaallluykduibffuerteanbts,ehnet
ol. Syst. 201Prof Robert dsmpidiegcnriaeonstetmstbhadeattewtiheteetnoboaturheneadseaarrseytcwe(Wnatslaypllobarcrooeuu1sg.8hS6tq0iu)n.itrTorehplesr,soefxoiermxecixteyapmtaifoptnleers,htaorigethhceoermrtuamxleaonwhaoedrneethavtoetlrwviebedustta,enbdduttodaivrfaeerrwe-
Evby sifiedinrelativeisolation(Wallace1859,1860).Theseastuteobservationssummarizethemost
ol. salienttaxonomicpatternsintheregion;anumberofadditionalpatternshavebeendocumented
c
v. E subsequently.
Re ThepracticesoftaxonomyandsystematicsintheIAAhavechangedsubstantiallyintheyears
u. sinceWallace.Improvedinfrastructurehasmadeexplorationofnaturalareaseasier,whichhas
n
n
A aidedthediscoveryofnewhabitats,andnewcollectingmethodsfurtheraidbiodiversityexploration
(e.g.,Mendozaetal.2010).Moleculardatagatheredinthelatetwentiethcenturyofferanum-
berofrefinementsovermorphology-basedmethodsinbiogeographybecause(a)DNAsequence
datagenerallyoffersalargernumberofcharactersthathelpdeterminerelationshipsamongtaxa,
(b)confidenceinthestrengthofrelationshipscanbeassessed,(c)relationshipsamongmorpho-
logically static taxa can be ascertained, (d) divergence times can be estimated, and (e) relative
probabilities of different evolutionary hypotheses can be gauged (Avise 2000, Knowles 2009).
Thesepropertiesallowtheevolutionaryhistoriesofco-distributedtaxatobecomparedspatially
andtemporallytoassessgeneralpatterns,andtheypermitphylogenetichistoriestobemapped
ongeologicalreconstructions,allowingcalibrationofdivergencetimeswithDNAsequencedata.
PhylogeneticandphylogeographicresearchintheIAA,muchlikeconservationbiologystudies
intheregion(Sodhi&Liow2000),haslaggedbehindotherpartsoftheworld.Thewealthof
www.annualreviews.org • Indo-AustralianBiogeography 213
ES42CH10-Lohman ARI 26September2011 14:33
Quezon, Philippines
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22
205-2on 11/ SSinugmaaptorare Pygconioanvoietrus
ol. Syst. 2011.42:Prof Robert Hall PSSSSiiiiennnnngggginaaaappppsuoooolrrrraeeeer Malaysia WesternSunda Shelf
Evby Singapore
ol.
c
v. E Figure3
Re PhylogeographichistoryoftheYellow-ventedBulbul,Pycnonotusgoiavier,demonstratingsomecommon
u. patternsobservedinanimalsdistributedacrosstheIndo-AustralianArchipelago(IAA).Reciprocal
n
n monophylyofBorneanandwesternSundaShelfpopulationssuggestslackofgeneflowbetweentheseareas
A
despiteterrestrialconnectivityduringthePleistocene,consistentwiththehypothesisofanecologically
impassablesavannahcorridorbetweenthetworegions.Similarly,monophylyofMindanaorelativetoother
PhilippinepopulationsimplicatesaroleforthisPleistoceneAggregateIslandComplexinPhilippine
biogeography.TheBayesiantreeisbasedonapproximately1,875bpofmitochondrialsequencedata;
posteriorprobabilitiesateverynodebetweendifferentregionsare1.TreeadaptedfromLohmanetal.
(2010);photocopyright(cid:2)c LimKianPengandusedwithpermission.
geologic,paleoclimatic,andbathymetricdataavailablefortheIAAenablestheinterpretationof
distributionsandphylogenyinlightoftheseextrinsicfactors.Here,wehighlightseveralrecurrent
themesinIAAbiogeographyillustratingpatternsofdispersalanddiversificationilluminatedby
molecularphylogeneticandphylogeographicevidence.Wesummarizesalientcross-taxonpatterns
emergingfromthesedata.
214 Lohmanetal.