洱海湖滨带大型底栖动物的群落结构

洱海是云贵高原第二大湖泊,拥有生物较为丰富的湖滨带和特有种,如螺蛳(Margarya melanioides)、绘环棱螺(Bellamya limnophila)。2009年5月和12月在洱海湖滨带开展调查,共采集到底栖动物30个分类单元;其中,寡毛类、摇蚊科幼虫和软体动物等主要类群为11种、7种和9种,分别占物种总数的36.7%、23.3%和30.0%,其它动物3种。在密度方面,群落结构以寡毛类为主,平均密度达488个/m2(占总丰度的89.7%),密度峰值出现在弥苴河口(7424个/m2);而在生物量方面则以软体动物占优势,平均生物量为67.26g/m2(占总丰度的91.4%)。按密度的平均相对丰度计算,霍甫水丝蚓(Limnodrilus hoffmeisteri)为第一优势种(平均相对丰度24.4%),其次为异腹腮摇蚊(Einfeldia sp.)(13.2%)、苏氏尾鳃蚓(Branchiura sowerbyi)(11.6%)和正颤蚓(Tubifex tubifex)(11.5%)。按生物量计算,圆田螺(Cipangopaludina sp.)为第一优势种(占总生物量的79.3%),其次为河蚬(Corbicula fluminea)(10.6%)和环棱螺(Bellamya sp.)(6.2%)。洱海的Shannon-Wiener指数平均为1.08,西岸比东岸的生物多样性指数要高。

Macrozoobenthos Community Structure in Aquatic-terrestrial Ecotones of Lake Erhai

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.