DOI: 10.1111/j.1466-8238.2009.00473.x © 2009 Blackwell Publishing Ltd www.blackwellpublishing.com/geb 607 Global Ecology and Biogeography, (Global Ecol. Biogeogr.) (2009) 18, 607–616 RESEARCH PAPER Blackwell Publishing Ltd Pervasive effects of dispersal limitation on within- and among-community species richness in agricultural landscapes Frederik Hendrickx 1,2 *, Jean-Pierre Maelfait 1,3 , Konjev Desender 1 †, Stephanie Aviron 4 , Debra Bailey 4 , Tim Diekotter 5 , Luc Lens 2 , Jaan Liira 6 , Oliver Schweiger 7 , Marjan Speelmans 3 , Viki Vandomme 2 and Rob Bugter 8 ABSTRACT Aim To determine whether the effect of habitat fragmentation and habitat hetero- geneity on species richness at different spatial scales depends on the dispersal ability of the species assemblages and if this results in nested species assemblages. Location Agricultural landscapes distributed over seven temperate Europe countries covering a range from France to Estonia. Methods We sampled 16 local communities in each of 24 agricultural landscapes (16 km 2 ) that differ in the amount and heterogeneity of semi-natural habitat patches. Carabid beetles were used as model organisms as dispersal ability can easily be assessed on morphological traits. The proximity and heterogeneity of semi-natural patches within the landscape were related to average local (alpha), between local (beta) and landscape (gamma) species richness and compared among four guilds that differ in dispersal ability. Results For species assemblages with low dispersal ability, local diversity increased as the proximity of semi-natural habitat increased, while mobile species showed an opposite trend. Beta diversity decreased equally for all dispersal classes in relation to proximity, suggesting a homogenizing effect of increased patch isolation. In con- trast, habitat diversity of the semi-natural patches affected beta diversity positively only for less mobile species, probably due to the low dispersal ability of specialist species. Species with low mobility that persisted in highly fragmented landscapes were consistently present in less fragmented ones, resulting in nested assemblages for this mobility class only. Main conclusions The incorporation of dispersal ability reveals that only local species assemblages with low dispersal ability show a decrease of richness as a result of fragmentation. This local species loss is compensated at least in part by an increase in species with high dispersal ability, which obscures the effect of fragmentation when investigated across dispersal groups. Conversely, fragmentation homogenizes the landscape fauna for all dispersal groups, which indicates the invasion of non-crop habitats by similar good dispersers across the whole landscape. Given that recoloniza- tion of low dispersers is unlikely, depletion of these species in modern agricultural landscapes appears temporally pervasive. Keywords Agricultural intensification, arthropods, community ecology, diversity partitioning, Europe, habitat diversity, metacommunity, nestedness, spatial scale. *Correspondence: Frederik Hendrickx, Entomology Department, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium. E-mail: frederik.hendrickx@naturalsciences.be †Deceased 1 Royal Belgian Institute of Natural Sciences, Entomology Department, Vautierstraat 29, 1000 Brussels, Belgium, 2 Terrestrial Ecology Unit, Biology Department, Ghent University, K. L. Ledeganckstraat 35, 9000 Gent, Belgium, 3 Institute for Nature and Forest Research, Kliniekstraat 25, 1070 Brussels, Belgium, 4 Agroscope Reckenholz-Tänikon, Research Station ART, Reckenholzstrasse 191, CH-8046 Zurich, Switzerland, 5 Justus Liebig Universität, IFZ – Abteilung Tierökologie, Heinrich-Buff- Ring 26-32, D-35392 Giessen, Germany, 6 Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, EE51005, Estonia, 7 UFZ – Helmholtz Centre for Environmental Research Leipzig-Halle, Department of Community Ecology, Theodor-Lieser-Str. 4, D-06210 Halle, Germany, 8 Alterra Green World Research, Landscape Centre, PO Box 47, 6700 Wageningen, The Netherlands INTRODUCTION Understanding the drivers of biodiversity change at different spatial scales is a primary topic in community ecology, conservation biology and biogeography. Species richness at larger spatial scales (i.e. regional, landscape or gamma diversity) depends on the average local or within-community species richness (alpha diversity) and richness among communities (beta diversity)