影响浑太河流域大型底栖动物群落结构的环境因子分析

于2012年5~6月对浑太河流域66个采样点的大型底栖动物进行调查采样.共采集到大型底栖动物72(属)种,其中水生昆虫51(属)种,占70.83%,环节动物7(属)种,占9.72%;节肢动物(属)4种,占5.56%;软体动物(属)10种,占13.89%.首先,采用相关分析从6类28个候选指标中筛选出EPT分类单元数、优势分类单元个体相对丰度、蜉蝣目相对丰度、毛翅目相对丰度、软体动物相对丰度、扁蜉科/蜉蝣目相对丰度、纹石蛾科/毛翅目相对丰度、寡毛类动物相对丰度、敏感类群相对丰度、耐污类群相对丰度、收集者相对丰度、黏附者相对丰度、香农-威纳多样性指数共13个指标用于表征浑太河流域大型底栖动物群落结构特征.然后,利用RDA方法分析了自然环境因子和反映人类活动压力的环境因子对大型底栖动物空间分异的影响.利用偏冗余分析(pRDA)比较了自然环境因子与人类活动压力因子对底栖动物群落结构影响的大小,以及流域、河岸缓冲区和河段尺度人类活动压力因子对大型底栖动物的影响.结果表明,所有环境因子可解释底栖动物群落结构空间变异的72.23%.纳入分析的人类活动压力因子解释了底栖动物群落结构空间变异的48.9%,纳入分析的自然环境因子解释了底栖动物群落结构空间变异的11.8%.河段尺度人类活动压力因子对底栖动物群落结构空间分异影响最显著.河段尺度人类活动压力因子可解释底栖动物群落结构空间分异的35.3%,其中,显著环境因子p H、栖息地质量、总氮、高锰酸盐指数、硬度、电导率、总溶解颗粒物和氨氮分别解释了4%、3.6%、1.8%、1.7%、1.7%、0.9%、0.9%和0.9%的底栖动物群落结构空间分异.河岸缓冲区和流域尺度土地利用对大型底栖动物空间分异的贡献分别为10%和7%.最后,采用相关分析比较了流域和河岸缓冲区尺度土地利用与水质、水文、栖息地质量以及底质的关系,结果表明流域尺度土地利用能更好地表征河流水质、水文、栖息地质量以及底质状况,也说明不同尺度环境因子对大型底栖动物群落结构的影响有联合效应.

Effect of Environmental Factors on Macroinvertebrate Community Structure in the Huntai River Basin in the Huntai River Basin

In May-June 2012, macroinvertebrates were investigated at 66 sampling sites in the Huntai River basin in Northeast of China. A total of 72 macrobenthos species were collected, of which, 51 species(70.83%) were aquatic insects, 10 species(13.89%) were mollusks, 7 species(9.72%) were annelids, and 4 species(5.56%) were arthropods. First, 13 candidate metrics(EPT taxa, Dominant taxon%, Ephemeroptera%,Trichoptera%, mollusks%,Heptageniidae/Ephemeroptera; Hydropsychidae/Trichoptera, Oligochaeta%, intolerant taxon%, tolerant taxon%, Collector%, Clingers%, Shannon-wiener index.) which belonged to six types were chosen to represent macroinvertebrate community structure by correlation analysis. Then, relationships between anthropogenic and physiography pressures and macroinvertebrate community structure variables were measured using redundancy analysis. Then, this study compared the relative influences of anthropogenic and physiographic pressures on macroinvertebrate community structure and the relative influences of anthropogenic pressures at reach, riparian and catchment scales by pRDA. The results showed all environmental factors explained 72.23% of the variation of macroinvertebrate community structure. In addition, a large proportion of the explained variability in macroinvertebrate community structure was related to anthropogenic pressures(48.9%) and to physiographic variables(11.8%), anthropogenic pressures at reach scale influenced most significantly macroinvertebrate community structure which explained 35.3% of the variation of macroinvertebrate community structure. pH, habitat, TN, CODMn, hardness, conductivity, total dissolved particle and ammonia influenced respectively explained 4%, 3.6%,1.8%, 1.7%, 1.7%, 0.9%, 0.9% and 0.9% of the variation of macroinvertebrate community structure. The land use at riparian and catchment scale respectively explained 10% and 7% of the variation of macroinvertebrate community structure. Finally, the relationships of land use at catchment and riparian scales and water quality factors, hydrological indicators, habitat, substrate types were analyzed. This study supports the idea that human pressures effects on river macroinvertebrate communities are linked at spatial scales and must be considered jointly.