Community structure of benthic macroinvertebrates in Lake Ulungur in Xinjiang

Abstract

乌伦古湖是我国十大内陆淡水湖之一, 同时也是新疆维吾尔自治区的第二大湖泊和主要渔业基地.近年来, 随着气候变化和人为因素的影响, 湖区水体营养状况、生物群落组成等均发生了较大变化.为揭示该湖大型底栖无脊椎动物的群落结构特征及其对生态系统变化的响应, 2006年11月至2008年7月设28个采样点对大型无脊椎底栖动物的群落结构特征进行了季节性调查分析.共采集到底栖动物87种, 其中水生昆虫61种, 占种类总数的70.1%, 寡毛类14种, 占总种数16.2%, 软体动物7种, 占总种数的8.0%, 其它类5种, 占总种数的5.7%.大型底栖无脊椎动物年平均密度为1015.01 ind./m², 年平均生物量为9.83g/m².各季度大型底栖动物的密度表现为冬季(1234.96 ind./m²) >春季(1044.47 ind./m²) >秋季(931.16 ind./m²) >夏季(849.44 ind./m²), 生物量同样表现为冬季(13.54g/m²)>春季(12.01g/m²)>秋季(8.37g/m²)>夏季(5.02g/m²).Shannon-Wiener多样性指数年均值为2.19, Margalef丰富度指数年均值为1.34.相关分析表明, 水深是影响大型底栖无脊椎动物密度和生物量分布的关键因子。;Lake Ulungur is the second largest lake of Xinjiang Uigur Autonomous Region and one of the ten largest freshwater lakes in China.With the impact of human activities and climate variation, nutrients and biotic communities in the lake have been changed obviously.To understand the community of benthic macroinvertebrates and its response to the changes in their environ-ment, we surveyed the benthic macroinvertebrates community in Lake Ulungur seasonally from Nov.2006 to July 2008.In total, 87 taxa were recorded, including 61 Insecta (70.1%), 14 Oligochaeta (16.2%), 7 Mollusca (8.0%) and other 5 taxa (5.7%).The annual density and biomass averaged 1015.01 ind./m² and 9.83 g/m², respectively.The density was highest in winter(1234.96 ind./m²), followed by spring (1044.47 ind./m²) and autumn(931.16 ind./m²), and lowest in summer (849.44 ind./m²).The biomass of benthic macroinvertebrates was highest in winter(13.54 g/m²), followed by spring(12.01 g/m²) and autumn(8.37 g/m²), and lowest in summer(5.02 g/m²).The annual average value of Shannon-Wiener diversity index and Margalef diversity index was 2.19 and 1.34, respectively.Correlation analyses indicated that water depth was the key factor influ-encing the standing crops of the benthic macroinvertebrates in this lake.