Copyright # 2005 John Wiley & Sons, Ltd. AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS Aquatic Conserv: Mar. Freshw. Ecosyst. 15: 549–557 (2005) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/aqc.742 Spatial patterns in pond invertebrate communities: separating environmental and distance effects ROBERT A. BRIERS a, * and JEREMY BIGGS b a School of Life Sciences, Napier University, Edinburgh, U.K. b Pond Conservation, Oxford Brookes University, Oxford, U.K. ABSTRACT 1. The nature and extent of spatial pattern in communities has important implications for their dynamics and conservation. Previous studies of pond ecosystems, over relatively small spatial scales, have found little evidence of spatial autocorrelation of community composition. Patterns in community composition over greater spatial distances have not been documented. 2. Here, data on macroinvertebrate communities and physico-chemical characteristics of 102 ponds over a 60  60 km area of Oxfordshire, UK, were used to examine evidence for spatial autocorrelation in community composition and to separate the effects of environmental similarity and physical distance on community similarity. 3. Overall similarity between communities was low, but showed significant positive spatial autocorrelation. There was evidence for both environmental and physical distance effects on spatial autocorrelation of community similarity. Community similarity was negatively related to differences in environmental conditions, but effects were only significant for large environmental differences. 4. When environmental effects were accounted for, there was significant positive spatial autocorrelation of community composition over inter-site distances of up to 13 km. These results suggest that interactions between pond sites, potentially through dispersal, are evident over larger spatial scales than has previously been appreciated, and emphasize the need to consider spatial issues when developing strategies for pond conservation. Copyright # 2005 John Wiley & Sons, Ltd. KEY WORDS: spatial autocorrelation; macroinvertebrates; dispersal; conservation; landscape; community composition INTRODUCTION The nature and consequences of spatial patterns in ecological communities has become an extremely active area of research in the last decade (Legendre and Fortin, 1989; Legendre, 1993; Koenig, 1999; Lennon, 2000; Perry et al., 2002), leading to an increasing awareness of the importance of processes acting over *Correspondence to: R. A. Briers, School of Life Sciences, Napier University, Merchiston Campus, Edinburgh, EH10 5DT, UK. E-mail: r.briers@napier.ac.uk