Data from: Ignoring spatial effects results in inadequate models for variation in littoral macroinvertebrate diversity

Studies focusing on the effects of spatial processes versus environmental
filtering on aquatic metacommunities have so far been focused almost
entirely on relatively isolated systems, such as sets of different lakes
or streams. In contrast, metacommunity patterns and underlying processes
within a single aquatic system have received less attention. In this
study, we aimed to examine how strongly variations in different diversity
indices are affected by spatial processes (dispersal) versus local
environmental conditions (species sorting) within a large lake system.
Modern biodiversity research focuses on multiple diversity facets because
different indices may be uncorrelated within and between facets, and they
may thus describe different phenomena. We investigated the relationship of
littoral macroinvertebrate diversity with environmental and spatial
factors using 10 indices of species, functional and taxonomic diversity.
Using spatial factors as proxies of dispersal, we decomposed variation in
diversity indices into fractions attributable to environmental and spatial
factors. Our results highlighted generally equal or higher importance of
spatial processes in controlling the variation in diversity indices when
compared to local environmental variables. Local environmental conditions
accounted for higher proportion of variation only in a single index (i.e.
taxonomic diversity). These findings suggest that the effects of high
dispersal rates (mass effects) may override the influences of local
environmental conditions (species sorting) on the diversity in
highly-connected aquatic system, such as large lakes and marine coastal
systems. Our results further suggest that biodiversity assessment and
environmental monitoring in highly-connected systems cannot rely solely on
the idea of environmental control. We hence recommend that the roles of
both environmental and spatial processes should be integrated in basic and
applied ecological research of aquatic systems.