COMMUNITY ECOLOGY - ORIGINAL RESEARCH Does dispersal ability affect the relative importance of environmental control and spatial structuring of littoral macroinvertebrate communities? Jani Heino Received: 6 March 2012 / Accepted: 24 August 2012 / Published online: 8 September 2012 Ó Springer-Verlag 2012 Abstract Both spatial processes and environmental con- trol may structure metacommunities, but their relative importance may be contingent on the dispersal ability of organisms. I examined the roles of spatial and environ- mental factors for the structuring of littoral macroinverte- brate communities across a set of lakes in a boreal drainage basin. I hypothesized that dispersal ability would affect the relative importance of spatial processes and environmental control, and thus the biological data were divided into four groups of species differing in dispersal ability. In general, the group of the strongest aerial dispersers showed greatest relative pure environmental control and least pure spatial structuring of community structure and species richness, while spatial processes seemed to be more important for the other three dispersal ability groups. However, these results were contingent on the indirect measure of spatial processes, with the spatial variables and connectivity variables providing slightly different insights into the spatial processes and environmental control of metacom- munity structuring. It appears, however, that dispersal ability has effects on the spatial processes and environ- mental control important in metacommunity organization, with strong dispersers being more under environmental control and less affected by spatial processes compared to weak dispersers. Keywords Community structure Á Macroinvertebrates Á Lakes Introduction Understanding the assembly of biotic communities has traditionally been a major aim of ecological research (MacArthur and Wilson 1967; Keddy 1992). A recently emerged field, metacommunity ecology, considers com- munity structure across a set of sites within the constraints of various regional and local processes (Leibold et al. 2004; Chase and Bentgtsson 2010). In this framework, regional processes include dispersal among localities, whereas local processes include biotic interactions and abiotic factors. Local factors can be considered as major environmental gradients, sorting species from the regional species pool to coexist locally. Local coexistence is pos- sible only if species are able to reach a locality through dispersal and to persist due to the suitability of environ- mental conditions, through source–sink dynamics or via patch dynamics (Cottenie et al. 2003; Leibold et al. 2004). In this respect, the island biogeography theory (MacArthur and Wilson 1967) and the metacommunity framework (Leibold et al. 2004) merge, with the aim to separate the influences of spatial processes and environmental control on the variation in biotic communities. The roles of spatial processes and environmental control in structuring biotic communities are, however, contingent on the dispersal abilities of the focal organism groups. For example, island biogeography studies have shown that less mobile species are often absent from distant islands or habitat fragments, leading to a decrease in species richness with isolation (MacArthur and Wilson 1967; Lomolino 1982; Prugh et al. 2008). A similar isolation effect can also Communicated by Carla Caceres. J. Heino (&) Ecosystem Change Unit, Finnish Environment Institute, P.O. Box 413, 90014 Oulu, Finland e-mail: jani.heino@ymparisto.fi J. Heino Department of Biology, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland 123 Oecologia (2013) 171:971–980 DOI 10.1007/s00442-012-2451-4