文档介绍：Applying landscape ecology to conservation biology: Spatiallyexplicit analysis reveals dispersal limits on threatenedwetland gastropodsKarla Niggebruggea,b, Isabelle Durancea, Alisa M. Watsona, Rob . Leuvenb,. Ormeroda,*aCatchment Research Group, School of Biosciences, Cardiff University, Cardiff CF10 3US, United KingdombDepartment of Environmental Science, Institute for Wetland and Water Research, Radboud University, Nijmegen, . Box 9010,6500 GL Nijmegen, herlandsARTICLEINFOArticle history:Received 21 September 2006Received in revised form27 June epted 11 July 2007Available online 5 September 2007Keywords:EutrophicationFragmentationGISGrazing marshesHabitat suitabilityInvertebratesNicheOrdinationABSTRACTThree gastropods in the UKred data book (RDB) occupy drainage ditches onthreatened graz-ing nitida, Anisus vorticulusandValvata macrostomaare affected by hab-itat loss, ditch management and eutrophication, but dispersal and fragmentation effectshavealso beenpostulated. Weusedlandscapeecological approachesto examinesucheffectsonthese and17 other gastropods onfour English marshes, bining ordinationto identify suitable habitat with spatially-explicit analysis of occupancy. Among all gastro-pods, the occupancy of suitable habitat declined signi?cantly as the distance to the upiedsite . nitidaandA. vorticuluswereamongthe species mostaffected, withmediannearest distances upied to upied suitable sites signi?cantly greater by3?4Xthan distances between occupied . macrostomawas not limited locally by dis-persal, but was absent from three out of four marshes with suitable habitat. Eutrophication(elevatedN) had no effects on distances between occupied and upied sites and didnot contribute to fragmentation. Although four non-threatened specieswereapparentlyalsolimited bydispersal, onlytwo(Armigercrista; Gyraulus albus) bination of thedispersal effects, upancy of suitable habitat (<50%) and small niche extent that char-acterized