Environmental and spatial drivers of beta diversity components of chironomid metacommunities in contrasting freshwater systems

Partition of beta diversity into components is a modern method that allows inferences about the underlying processes driving metacommunities. Based on two alternative approaches, we examined the patterns of beta diversity components of chironomids in relation to environmental and spatial gradients in three contrasting freshwater ecosystems. Beta diversity and its replacement component increased from environmentally less heterogeneous lake, through more complex wetland to stream network. Constrained ordination revealed that environmental heterogeneity and spatial processes explain some variation of the patterns of pairwise beta diversity components. Both beta diversity partitioning approaches emphasised the importance of habitat structure and food resource in structuring chironomid metacommunities. However, concurrent approaches provided contrasting results regarding the relative role of underlying mechanisms related to species replacement and richness. Therefore, further research is needed to clarify which of the beta diversity partitioning approaches should be preferred more widely in ecological studies.