The role of environmental and spatial factors in the assembly of aquatic insect communities in southern Brazilian temporary ponds

Metacommunity organisation in temporary ponds is assembled by spatiotemporally varying processes that are also contingent on the species' dispersal ability and scale of observation. Aquatic insects are useful models to study the relative contribution of environmental and spatial factors to community assembly in view of the differing dispersal ability existing in the species from this group. We assessed the metacommunity organisation of aquatic insects and subsets of strong- and weak-flying insects in relation to environmental (habitat structure; water chemistry; climate) and spatial factors in temporary ponds ranging along a latitudinal gradient in southern Brazil. Local and climate environmental factors (water chemistry and temperature) along with fine-scale spatial factors were the main drivers of the total insect community, although their relative importance shifted between subsets of weak- and strong-flying insects. The composition of strong-flying insects was structured by climate and fine-scale spatial factors, while weak-flying insects, by local (water chemistry) and spatially structured climate. This suggests that strong-flying insects showed stronger signatures of mass effects at finer scales, while weak-flying insects were more strongly affected by species sorting coupled to local environmental factors and regional climate. In summary, our results indicate that the relative importance of assembly processes for metacommunity organisation of aquatic insects in temporary ponds is contingent on dispersal ability.