辽河流域典型支流土地利用方式对大型底栖动物群落时空分布特征的影响

通过辽河流域典型支流(清河和凡河)不同土地利用类型区3个水期大型底栖动物及环境因子调查,研究土地利用方式对大型底栖动物分布特征的影响.结果表明,河流大型底栖动物群落四节蜉科(Baetidae)、扁蜉科(Heptageniidae)、纹石蛾科(Hydropsychidae)及石蝇科(Perlidae)等生物类群主要分布在辽河流域内林地为主的河流中;以耕地和居民点为主的土地利用方式下,河流大型底栖动物主要以摇蚊科(Chironomidae)类群为主;颤蚓科(Tubificidae)等寡毛类大型底栖动物在以城市发展为主的土地利用区域内河流中优势明显.河流中大型底栖动物生物多样性、丰富度及EPT%由高到低依次为林地耕地居民点城市,FBI值由低到高依次为林地耕地居民点城市.不同土地利用方式导致河流生境因子空间差异性显著,大型底栖动物群落相似性较低,且生物密度在空间上呈显著差异,但时间上差异不显著.底质、DO与大型底栖动物多样性等指数呈正相关关系,TN、TP、NH3-N、BOD5、CODCr与大型底栖动物生物指数呈不同程度负相关关系.生物与环境联合分析(BIO-ENV)表明,底质、DO、TN、BOD5是影响区域内大型底栖动物群落特征的最显著的主导环境因子.综合上述研究结果可得,土地利用方式通过对河流生境及水质产生影响,进而使大型底栖动物群落组成及多样性特征发生明显变化.

Impacts of land use on the spatial and temporal distribution characteristics of the macroinvertebrates in the Liao River basin

To investigate the effects of land use on the distribution of macroinvertebrates, the relevant environmental factors and the macroinvertebrates associated with different land use types in two typical tributaries (Qing River and Fan River) in the Liao River basin were studied during three periods. The results indicated that Baetidae, Heptageniidae, Hydropsychidae and Perlidae were the main macroinvertebrate communities in the woodlands of the Liao River basin. Chironomidae was the major taxon in the farmland and rural land use types. Tubificidae and other oligochaetes were dominated in the urban group. The diversity index, richness and EPT% of the macroinvertebrates were in the order of woodland> farmland> rural> urban land use types, and the FBI value presented the opposite order. Environmental variables among macroinvertebrate communities in the four major land use types presented significant inter-community and spatial differences, but there were no significant temporal differences. The diversity index of the macroinvertebrates was positively correlated with the substrate and DO and negatively correlated with the TN, TP, NH₃-N, BOD₅ and COD_Cr. The BIO-ENV analysis implied that the environmental factors that most affected the macroinvertebrate communities were the substrate, DO, TN and BOD₅. In conclusion, the variation in land use significantly affected the community structure and diversity of the benthic macroinvertebrates by changing the river habitat and water quality.