Global-biodiversity-scenarios-and-landscape-ecolog

RESEARCHARTICLEGlobalbiodiversityscenariosandlandscapeecologyGraemeS.CummingReceived:11October2006/Accepted:15October2006/Publishedonline:13January2007
SpringerScience+BusinessMediaB.V.2006AbstractThecompositionofecologicalcom-munitiesisbothcauseandconsequenceofland-scapepattern.Predictingbiodiversitychangeinvolvesunderstandingnotonlyecologyandevolution,butalsocomplexchangesinhumansocietiesandeconomies.Scenariosofferalessrigidapproachtothinkingaboutbiodiversitychangeinapolicyandmanagementcontext.Theyshiftthefocusofresearchandmanagementfrommakingsingularpredictionsanddevelopingsingle‘best’strategiestoexploringuncertaintiesandassessingtheoutcomesofalternativepolicies.ThefourMillenniumEcosystemAssessment(MA)biodiversityscenariosillustratecurrentapproachestobiodiversityestimationinglobalscenarios.TheMAbiodiversityscenariosarebuiltaroundthespecies–arearelationshipandthemagnitudesofafewarea-dependentpro-cessessuchasnitrogendepositionandclimatechange.Someofthemostobviouslandscape-relatedomissionsfromtheMAscenariosarepattern-processfeedbacks,scaledependencies,andtheroleoflandscapeconfiguration.WhiletheMAhassetanewstandardforbiodiversityscenarios,futureexerciseswouldbenefitfromamoremulti-scaleandmoremechanisticframe-work.IuseexamplesfromresearchonthelandscapeecologyandbiogeographyofAfricantickstoillustratehowahypothesis-basedap-proachcanbeusedtoanalysethemulti-scale,multi-leveldriversofchangeinpatternsofspeciesoccurrences.Twoofthemostimportantchal-lengesforthefuturedevelopmentofbothland-scapeecologyandbiodiversityscenariosaretobecomemoremechanistic(lesspattern-based)andmoregeneral(applicableacrossdifferentlandscapes).KeywordsDiversity
Scenarioplanning
Speciesrichness
Ticks
Ixodidae
Climatechange
MillenniumAssessment
Policy
Management
Scale
Species–arearelationshipIntroductionThestudyofdiversityhasbeenthesourceofmanyimportantinsightsintotheorganizationofeco-logicalcommunities.Inlandscapeecology,diver-sityhasbecomeafocaltopicthroughstudiesofsuchphenomenaaselevation-relatedchangesincommunitycomposition(Lomolino2001;Whit-taker1960),latitudinalpatternsinspeciesrich-nessandabundances(Gaston2000;Pianka1966;Stevens1989),diversity–stabilityrelationshipsG.S.Cumming(&)PercyFitzPatrickInstituteofAfricanOrnithology,UniversityofCapeTown,Rondebosch,7701,CapeTown,SouthAfricae-mails:[e-mail];[e-mail]123LandscapeEcol(2007)22:671–685DOI10.1007/s10980-006-9057-3(LevineandD’Antonio1999;Pimm1984),distur-banceecology(Connell1978;Whittaker1995)andspeciesturnoverratesinspaceandtime(Bennettetal.2004;Bestelmeyeretal.2003;Herwitzetal.1996).Sincedifferentspeciesper-formdifferentecologicalfunctionsandprovidearangeofgoodsandservicestohumans(Dailyetal.1997),theecologyofbiodiversityisalsoimportantinunderstandingecosystemfunction(Ivesetal.2000;Naeem2002)andassociatedmanagementissues.Weareengaginginahuge,uncontrolledmanipulationoftheworld’secosystems(Jacksonetal.2001;Vitouseketal.1986,1997).Thecurrentrateofspecieslossishigherthanatanyprevioustimeinhumanhistory(CeballosandEhrlich2002;Chapinetal.2000),placingconsid-erablepressureonscientists,politiciansandpolicymakerstoprovideriskassessmentsandtotakeappropriateactiontoavertpotentialdisas-ters.Someofthemostpressingchallengesrelat-ingtobiodiversityincludeinventories(howmuchbiodiversityisthere,wheredoesitoccur,andwhereisitbeinglost?);linkingbiodiversitytofunction(whatdoesbiodiversitycontributetosystemfunction,andhow?);andprotection(howcanwebestsustainbiodiversityinthefaceofextrememodificationofecosystems?).Achievingthegoalsofbiodiversityconserva-tionrequiresanintegrativeapproachthatrecog-nizesnotonlytheneedforscientificrigourbutalsothesocietalnatureofconservationanditsneedforsocial,economic,andpoliticalsupport(DietzandAdger2003;Ehrlichetal.1999).Scenariosofferanapproachforthinkingaboutthefutureinaninterdisciplinarycontext.Inparticular,biodiversityscenariosarecomplemen-taryaccountsofplausiblefuturesthatdetailpotentialchangesintheabundanceandspeciesrichnessoforganismsunderalternative,specifiedassumptionsanddrivers.Thereisconsiderablepotentialforsynergiesbetweenlandscapeecologyandbiodiversityscenarios.Ifocusontwoaspectsofthistheme:thecontributionsoflandscapeecologytothequantitativeestimationofcurrentandfuturepatternsofbiodiversity,andthechallengesforlandscapeecologythathavebeenraisedduringrecentattemptstodevelopglobalbiodiversityscenarios.Althoughscenariosaredevelopedprimarilytoaidpolicydevelopmentandprovideinformationfordecisionmakers,theirfocusonthefutureprovidesasterntestofourabilitytomakereliablescientificpredictions.PredictingchangesinglobalbiodiversityOccurrencesofanyorganismcanbeconsideredassuccessfulorganicsolutionstoasetofdynamicenvironmentalcontraintsorrequirements.Hutch-inson(1957)distinguishedbetweentheactualniche(thefullrangeofconditionsinwhichthespeciescouldlive)andtherealisedniche(condi-tionsinwhichaspeciesdoeslive).Dependingonthesizeoftheactualnicheinrelationtotherealisedniche,therecanexistsubstantialdiffer-encesinthelikelyresponsesoforganismstoclimatechange,evenwithi