Effects of habitat types and within lake environmental gradients on the diversity of chironomid assemblages

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The roles of environment, site position, and seasonality in taxonomic and functional organization of chironomid assemblages in a heterogeneous wetland, Kis-Balaton (Hungary)

Environmental heterogeneity plays a determinant role in structuring taxonomic and functional composition of local assemblages via various interacting processes as synthesized in the metacommunity theory. In this study, we evaluate the relative roles of local environmental and landscape filters, spatial constraints and seasonality in organization of assemblages of Chironomidae (Diptera), a diverse aquatic insect group with winged adults, in an extremely heterogeneous wetland system, Kis-Balaton, Hungary. As expected, local environmental variables explained a substantial proportion of assemblage variance mainly along sediment structure, macrophyte coverage, and decomposing plant matter gradients. Considering the narrow spatial range of the study area, pure spatial influence was unexpectedly strong, likely because of the dispersal limitation related to tall terrestrial vegetation patches and mass effect related to the uneven distribution and area of certain microhabitats and their species pools. However, landscape- and season-related variability proved to be low or negligible. Taxonomic and functional feeding guild (FFG)-based approaches revealed the same main trends in assemblage data; however, FFGs seemed to track environmental changes more tightly. We argue for the common use of taxonomic and functional-based approaches and advise the improvement of species optima and tolerance spectra databases to expand bioassessment power

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

The role of biotic and abiotic environmental factros in distribution of lake benthic chironomid assemblages

Az élőlény együttesek eloszlásának és diverzitásának vizsgálata kulcsfontosságú az ökológiai folyamatok megértése szempontjából. Az eloszlást befolyásoló folyamatok, illetve az ezek mögött húzódó környezeti és térbeli változók jelentősége több tényezőtől is függ. Egyebek között a vizsgált térbeli léptéktől, az élőhelyi heterogenitástól, vagy a faji jellegektől. Viszont arról, hogy egyes térbeli és környezeti tényezők miként hatnak az árvaszúnyolárvák kis léptékű, egy adott víztéren belüli eloszlására, viszonylag keveset tudunk. Ezt vizsgáltam dolgozatomban. Exploring the distribution and diversity of communities is essential for understanding the ecological processes. Importance of processes and underlying environmental and spatial variables affecting distribution of organisms depends on several factors, such as the examined spatial scale, habitat heterogeneity or species traits. But there is a clear gap in our knowledge about the contribution of certain spatial and local environmental processes to distribution of chironomid larvae at small spatial scale such for instance within a lake. Therefore my specific aim was to investigate these processes.N