凉水、帽儿山低级溪流中水生昆虫的群落特征及水质生物评价

Community characteristics of aquatic insects and bioassessment for water quality in lower order streams in Liangshui and Maoershan watersheds,Heilongjiang,China

在东北林业大学凉水国家级自然保护区和帽儿山实验林场,对3种类型低级溪流中水生昆虫进行采集、鉴定,分析水生昆虫群落组成、季节优势集中性和取食功能群,并应用指示生物法、Shannon-Weiner多样性指数、群落相似性系数和BI指数对溪流水质进行生物评价。共采集到水生昆虫4907个,分别隶属于8目38科,其中,毛翅目、蜉蝣目、襀翅目和双翅目为四大优势类群,个体数量占水生昆虫总数量的91.13%。原始林溪流中水生昆虫个体数量最多,占总数的58.98%,次生林溪流次之,农田溪流最少。次生林溪流水生昆虫物种多样性要高于原始林和农田溪流,且其各种取食功能群比例较均衡。齿角石蛾科、鳞石蛾科、新蜉科和黑襀科昆虫可以作为溪流清洁水质的指示生物。水生昆虫季节优势集中性与Shannon-Weiner多样性指数水质评价结果之间具有相关性,即随溪流水质污染程度的加重,水生昆虫的物种多样性逐渐减少。群落相似性系数的分析表明,原始林溪流和次生林溪流水质对水生昆虫的群落组成没有影响,农田溪流则产生中等影响。生物指数(BI)评价结果显示除了农田溪流10月的水质为轻污染外,其余时间3种溪流的水质都能达到清洁标准以上。

Aquatic insects in lower order streams under landscapes with different vegetations in Liangshui National Natural Rserve and Maoershan Experimental Forest Farm were collected and identified to analyze the community composition, seasonal dominant concentration and foundational feeding group, in May. August and October, 2006. The stream water quality was assessed by biological indicator using Shannon-Weiner diversity index, community similarity index and biotic index. Totally 4907 aquatic insect individuals were collected and identified to 38 families, 8 orders. Trichoptera, Ephemeroptera, Plecoptera and Diptera were dominant groups, accounting for 91.13% of all the aquatic insects collected. Most aquatic insects were found in old growth forest streams in Liangshui, accounting for 58.98% of the total, much more than that found in second growth forest streams in Maoershan, and the least were found in farmland streams in Maoershan. The aquatic species diversity in second growth streams was greater than that in the old growth and farmland streams, and the percentages of foundational feeding group in second growth streams were more balanced. The species in Odontoceridae, Neoephemeridae and Capniidae were selected as biological indicators for high stream water quality. There was relationship between seasonal dominant concentration of aquatic insects and the assessment results for water quality with Shannon-Weiner diversity index, the species diversity reduced gradually with the increasing of water pollution level. Community similarity index indicated that the composition of aquatic insect community was not influenced by water quality in old growth and second growth streams , but moderate influence was found in farmland streams. The results of biotic index analysis suggested that water quality of all streams surveyed was good at anytime except for farmland stream which was slightly polluted in October.