The littoral benthic macroinvertebrate community as a reflection of environmental heterogeneity

Abstract

The lakes littoral zone shows high spatial heterogeneity characterized by physical and chemical parameters of the water column and sediment which in the present study allow us to describe the structure and variability of the spatial distribution of the benthic macroinvertebrates (BMI) community of Lake Alchichica, Puebla. At Alchichica, the lakes water level reduction and the presence of al almost continues stromatolites ring has generated a heterogeneous littoral zone with regions in direct contact with the limnetic zone of the lake but in the other extreme, regions totally isolated from it. In this way, the littoral zone allows us to recognize a desiccation process of the lake. Goals. Thus, the study allows us to describe the effects of the desiccation process on the BMI community structure. Methods. Eleven sampling stations were located along the littoral zone. At each station environmental variables were measured and benthic macroinvertebrates were sampled. Results. We identified 21 BMI taxa among which the dominant in density and frequency are the oligochaete Limnodrilus hoffmeisteri and the amphipod Hyalella azteca. Environmentally, the sampling stations could be divided in those stations with open communication with the limnetic zone and others almost or totally separated from the main water body. Conclusions. There is a decline in the taxonomic richness, diversity, maximum diversity, and evenness but not in density, as the communication with the limnetic zone decreases. The sediment texture changes from sandy bottom in the communicated stations to clayed-silt in those isolated which in turn favors a change in the dominant taxon from H. azteca in sandy bottoms to L. hoffmeisteri in silty-clayed bottoms.