Macrozoobenthos Community Structure in Aquatic-terrestrial Ecotones of Lake Erhai
洱海湖滨带大型底栖动物的群落结构

Lake Erhai is the second largest plateau 1ake located in Dali City of Yunan Province. It belongs to deep lake and covers rich aquatic-terrestrial ecotones. Since its characteristics, it possesses endemic zoobenthos, such as Margarya melanioides and Bellamya limnophila. However, its macrobenthos community is still poorly investigated. Herein, surveys of macrobenthos were carried out in May and December 2009 in the whole aquatic-terrestrial ecotones of the lake. A total of 30 taxa was collected. Among which, oligochaete, chironomid and mollusc were main groups, and recorded 11 species (36.7% of the total number of species), 7 (23.3%) and 9 (30.0%), respectively. Oligochaetes dominated in the total density, and the average value was 488 ind./m2 (90% of the total abundance), with the highest one occurred in the mouth of Miju river (7424 ind/m2). Mollusks, however, covered 97% of the total biomass (67.26 g/m2). The first dominant species was Limnodrilus hoffmeisteri (average relative abundance is 24.4%), following by Einfeldia.sp. (13.2%), Branchiura sowerbyi (11.6%) and Tubifex tubifex (11.5%). The mean Shannon-Wiener index was 1.08, and the value at the west region was higher than that of east one.