Climatic Influences on Survival of Migratory African Reed Warblers Acrocephalus baeticatus in South Africa

[摘要] Thefocusofmostresearchontheinfluenceofrecentclimatechangeonbirdshasbeenonthenorthernhemisphere.Climatechangehasbeendifferentinthesouthernhemisphere,prohibitingextrapolationfromnorthernresearchfindings—andinferenceregardingfutureclimatechange—tospecieslivingthere.WeinvestigatedthecorrelationbetweenclimaticconditionsandsurvivalofamigratorypopulationofAfricanReedWarblersAcrocephlausbaeticatusinPaarl,SouthAfrica.Weusedtemperatureandrainfallinitsbreedingarea,andNormalizedDifferenceVegetationIndex(NDVI)initswinteringarea,CentralAfricaaroundtheCongoBasin.Wefittedcapture-mark-recapturemodelsforopenpopulationstoa12-yearringingdataset(1998–2010).Afteraccountingfortransience—thisspeciesexhibitshighbreedingsitefidelity—witha‘Time-Since-Marking’modelwefoundameansurvivalprobabilityof0.79±0.04SE.RainfallandNDVIdidnotinfluencesurvivalinthisdataset.Meantemperature(Aug–Apr)hadapositiveeffectonsurvival:anincreaseof1.6°Cwasassociatedwithanincreaseofannualsurvivalfrom0.69±0.05to0.88±0.03.Highertemperaturescouldhaveincreasedlocalsurvivalbyprovidingmorefoodandbreedinghabitat,therebyincreasingadultbodyconditionandreducingforagingcosts,predationandterritorialconflicts.Eventhoughwewouldneeddataonabundanceandreproductiontoquantifytheeffectsofclimaticconditionsonpopulationgrowth,wefoundacleareffectofclimaticvariationonakeydemographicparameter,adultsurvival.

[学科分类] 动物科学

[关键词] Wintering Area