Habitat suitability evaluation of a benthic macroinvertebrate community in a shallow lake

The relations between benthic macroinvertebrate communities and eco-factors usually are nonlinear and highly complex, and are often difficult to evaluate. In this study, canonical correlation analysis (CCA) and a generalized additive model (GAM) were applied to identify the key eco-factors that influence the community characteristics of benthic macroinvertebrates in a shallow water lake-Baiyangdian Lake. The water depth (H), water transparency (secchi disc depth, SD), concentration of chlorophyll-a (Chl-a), water temperature (T), concentration of dissolved oxygen (DO), oxidation and reduction potential (ORP), ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N) in water, median particle diameter (D-50), ammonium nitrogen in the substrate (NH4-N-soil), and biomass of macrophytes, are the main eco-factors affecting the spatial distribution and structure of the benthic macroinvertebrate community in the shallow freshwater lake. This study is the first to introduce GAM to habitat suitability evaluation for benthic macroinvertebrates in large shallow lakes, and to use the Margalef index (d(M)) instead of individual indicator species to indicate diversity variation. Five factors, including H, T, NH4-N-soil, organic matter (OM) in the substrates, and the biomass of macrophytes, were selected in the optimal model by stepwise regression. The response curves generated by the GAM indicated that the diversity of benthic macroinvertebrates was negatively correlated with H and (NH3-N-soil) and was positively correlated with T and OM. The response curve showing the relation between taxa diversity and the biomass of macrophytes was unimodal. The current study examined the combined influence of multiple eco-factors on benthic macroinvertebrates, and increased understanding of relations between the benthic macroinvertebrate community and eco-factors in a shallow lake system.