Spatio-temporal dynamics of zooplankton communities (Rotifers, Cladocerans, Copepods) and water quality of Lake Léré (TCHAD)

Abstract

Lake Léré is situated in the Mayo-Kebbi locality southwest of Chad, it is the site for RAMSAR since 2001 hosting manatee (Trichechus senegalensis). This lake has been under study with the aimed of determining the structure of zooplankton community from February 2016 to April 2017. For this study, three sampling stations were chosen and divided into 2 to 3 layers from water surface towards the bottom. A total of 49 zooplanktonic species were identifiedin LakeLéré. This was dominated by Rotifers community with more than 75% (38 species).Rotifers and Copepodsdominated withabundance proportions of 78.10 and 60.04% respectively in the dry season. This was relatively higher compared to the rainy season (21.89 and 39.95%). In the Cladocère communities, a higherabundance was observed in the rainy season of 85.39% and 14.6% in the dry season. Therewere no significant differences between the physicochemical parameters, the sampling stations and between the different sampling levels.Thehigh values of Sorensen similarity index, shows the homogeneity of the waters of the lake and justifies the absence of significant differences in the specific richness between stations. The specific richness of zooplankton community in Lake Léré and its physico-chemical variables lead to a conclusion of the mesotrophic state of the lake's waters.