渭河流域鱼类群落结构特征及其完整性评价

于2011—2013年在渭河流域进行了4次鱼类调查,分析渭河流域鱼类群落结构特征及人类活动影响下渭河流域鱼类群落结构的完整性. 调查共采集到鱼类51种,隶属于5目10科33属,其中鲤科和鳅科鱼类最多,分别占43.14%和29.41%,是渭河流域鱼类群落结构的主要组成. 流域上、中、下游鱼类分别为32、39和42种. 采用MIWB(改良健康指数)评价渭河流域鱼类完整性. 结果表明,渭河流域鱼类完整性较低,秋季35.60%的采样点为较好和健康水平,而春季仅有15.00%的采样点为较好和健康水平,秋季鱼类完整性明显好于春季. 空间上,渭河源头至宝鸡干流及南岸支流(藉河和黑河)、北岸支流(通关河和千河)的鱼类完整性较高,渭河关中地区、泾河中下游和北洛河源头与下游鱼类完整性较差. 

Fish Community Structure and Biological Integrity in the Wei River Basin

Rapid population growth and economic development are seriously threatening the biological integrity of freshwater ecosystems in the Wei River basin. Fish are important components in freshwater ecosystems, and the changes in fish assemblages in response to human disturbances may provide useful information on biological integrity. Fish assemblages in the Wei River basin were sampled four times between 2011 and 2013. A total of 51 species, belonging to 10 families and 5 orders, were collected and were dominated by species of Cyprinidae (43.14%) and Cobitidae (29.41%). Fewer species were collected from sites located in the upper Wei River basin (32 species) compared with the middle and downstream locations (39 and 42 species, respectively). Modified index of well being (MIWB) based on fish abundance, biomass and diversity was used to assess the biological integrity in the Wei River basin. Biological integrity of the Wei River varied substantially throughout the catchment and over the year. Fish integrity in the autumn was better (35.60% of all the sites were in good or excellent condition) than that in spring (15.00% of all the sites were in good or excellent condition). Biological integrity from the headwater to Baoji City, tributaries in the south bank-Jie River and Hei River and tributaries in the north bank-Tongguan River and Qian River were better, whereas those in Guanzhong district, middle and downstream in the Jing River and headwater in the Beiluo River were worse. Biological integrity assessment provides an appropriate framework to evaluate ecosystem health, and is expected to play a key role in watershed management of the Wei River basin.