Abundance of Invertebrates and Foraging Success of Black-Tailed Godwit Limosa limosa Chicks in Relation to Agricultural Grassland Management

[摘要] EffectsofagriculturalintensificationonavailabilityofgrasslandinvertebratesasfoodforchicksofthedecliningBlack-tailedGodwitLimosalimosawerestudiedinTheNetherlands.Invertebratesweresampledwithphoto-eclectorsinwetgrasslandsusedforintensivedairyfarming(highfertiliserinput,2–3cutsstartingearlytomid-May)andinameadowbirdreserve(moderatefertiliserinput,onecutinmid-June).Invertebrateswereslightlymoreabundantinreservethaninagriculturalfieldsbeforethefirstcutofthelatter.Inthe4–6weeksbetweenthefirstcutofagriculturalfieldsandthatofreservefields,invertebratesweremuchmoreabundantonreservefields.Thisisthemainperiodofgodwitchicks'presence.Meansizeofarthropodswassimilarunderthetwomanagementregimes,butlargeColeopteraweremoreabundantinagriculturalfieldsearlyintheseason.Inaforagingexperiment,captiveraisedgodwitchicksingested31%fewerpreyperunittimewhenforagingincutagriculturalgrasslandsthaninuncutreservefields,adifferencelargeenoughtocompromisechickgrowthandsurvival.Wildbroodsstronglyselectedtostayinreservefields,especiallyafteragriculturalfieldshadbeencut,andtravelledtowardsreservefieldsoverdistancesuptomorethan0.5km.PreferenceforreservegrasslandsdeclinedfromearlyJuneonwards.Weconcludethatpostponingmowingdates,inreservesoronfarmlandbymeansofagri-environmentinitiatives,improvesfeedingandsurvivalconditionsforgodwitchicksandotherinsectivoresfeedinginthegrasslandsward,inadditiontoitsbeneficialeffectonhatchingsuccess.

[学科分类] 动物科学

[关键词] Chick Survival