Influence of habitat characteristics on lacustrine macroinvertebrates: Lake Viverone as a case study

A combined analysis performed on Lake Viverone (Piedmont) linking the composition of the littoral macroinvertebrate fauna with the benthic quality index used for lake quality classification and some hydro-morphological parameters evaluated through the application of the lake habitat survey is presented. Hydro-morphological parameters comprised the characteristics of the littoral and sub-littoral substratum type, the bank characteristics, and the anthropic impacts along the shore. The lake was sampled during water mixing (spring) and stratification (autumn) with a grab in soft sediment, according to the national standardized protocol in the littoral, sublittoral and profundal areas, but here an in-depth description of the littoral area is provided. Canonical correlation analysis to evaluate the effects of anthropic pressures on the littoral benthic community was applied. According to the described numerical analysis, i) macroinvertebrates composition and sampling stations can be classified in three principal groups, according to seasonality and anthropic impacts; ii) correlations between the benthic quality index and the hydro-morphological variables were high. It is clear that to better understand the real effects of hydro-morphology on macroinvertebrates distribution and composition, it is necessary to expand the number of sampling sites along the coast to verify the robustness of our hypothesis.