Annual production, trophic basis and ingestion currency of dominant caddisfly (<i>Hydropsyche</i> sp.) in Shengli River, Bahe catchment, the middle reach of the Yangtze River basin

Abstract

为了加强长江中游地区大型无脊椎底栖动物的研究工作,2009年3月至2010年3月,对长江中游巴河支流的胜利河毛翅目优势种的生产力和营养基础进行了为期一年的调查研究.结果表明,胜利河中主要毛翅目优势种纹石蛾的生活史为一年3代.一至四级河流中,其生物量周年平均值分别为1.77、7.80、44.82、51.55 mg/m².采用体长频率法测算的年均生产量为7.72 mg/m²,P/B系数为13.21.利用肠内含物分析法研究了胜利河中纹石蛾的营养结构.比较一至四级河流的营养基础发现,无形态碎屑为纹石蛾最常见的食物,占肠内含物的45.22%~62.92%;而对生产量贡献率最高的多是动物组织,达52.86%~68.58%.各季节的营养基础状况也有差异,春季无形态碎屑所占比例和对生产量的贡献率较高,而夏、秋和冬季动物组织则有更高的生产量贡献率.一至四级河流的年均物质通量分别为11.83、34.76、237.52和273.17g/(m²·a).由此可见,该优势种在河流生态系统中发挥着重要作用.;In order to enrich the knowledge on the benthic macroinvertebrates in the middle reach of Yangtze River, a one-year investigation from March 2009 to March 2010 on secondary production and trophic basis of the dominant caddisfly in Shengli River (Shengli Town, Luotian County, Hubei Province), Bahe catchment, the middle reach of the Yangtze River Basin, was conducted. The result showed that the dominant caddisfly Hydropsyche sp. was trivoltinism. From the 1st to 4th rivers, the annual average biomasses of this species are 1.77, 7.80, 44.82 and 51.55 mg/m², respectively. Its annual production and P/B calculated with size (instar) -frequency method is 7.71 g/m2 and 13.21, respectively. Foregut content analysis showed that amorphous detritus was the dominant food of Hydropsyche sp., constituting 45.22%-62.92%, while the animal material usually gave the biggest contribution to secondary production, up to 52.86%-68.58%. In spring, amorphous detritus occupied the largest proportion and contributed most production, while in summer, autumn and winter animal material contributed the largest part of production. The annual ingestion currency of the species in different order rivers was 11.83 g/(m2 ·a) for 1st, 34.76 g/(m2 ·a) for 2nd, 237.52 g/(m²·a) for 3rd, and 273.17 g/(m²·a) for 4th, respectively. The study indicated that this caddisfly played an important role in the material cycling and energy flow of the Shengli River ecosystem.