The Relationship Between Characteristics Of Macroinvertebrates Assemblages With Habitat Factors In Liao River Basin

Liao River, as one of seven major rivers in China, provides water supply for both urban and rural people, industrial and agricultural activities with its unique way. Liaoning Province is an old industrial basin, with a long history of traditional industrial development. Heavy chemical industry pollution within the basin, has formed a characteristic mode of contamination. Due to the intense interference of human activities, over-exploitation and ecological destruction, aquatic biodiversity significantly reduce and aquatic ecosystem quality deteriorate.Macroinvertebrates have been used as bioindicators for integrative measurement of ecosystem health in rivers due to their advantages of limited mobility and large-scale applicability, and a relatively long lifespan and distribution throughout the length of rivers as compared with water physicochemical parameters, we studied benthic macroinvertebrates characteristics in the Liao River basin. The objectives of this study were to identify their linkages with the habitat factors, and assess river health conditions. The relationship between macroinvertebrates community structure and the third level aquatic eco-functional zoning was researched in Fan River basin to verify the rationality of aquatic eco-functional zoning.Forty sampling sites were selected in the Liao River basin. Macroinvertebrate samples and water quality samples were collected and status of the habitat factors were recorded at the same river location. From those samples, total nitrogen (TN), ammonia-nitrogen (NH3-N), dichromate index (CODcr), total phosphorous (TP), suspended solids (SS) etc. were measured in the laboratory. We collected58benthic macroinvertebrate taxa that belonged to4phyla and7classes from Liao River basin. Clustering analysis of macroinvertebrate abundance divided the40sampling sites into two groups, group1was composed by most sites of upstream tributary, and group2was composed by downstream most sites.Comprehensive comparison of the environmental conditions of the sampling sites by habitat suitability, the habitat suitability of group1was higher than that of group2on the spatial pattern and the difference was significant. The correlation analysis showed that among the influential indexes of habitat suitability, the substrate index (mineral sediment and organic matter) was the main factor that affected the biological characteristics of group1and group2. CCA ordination analysis showed that the main impact factors were water temperature, aquatic plants and the change of riparian vegetation on the temporal dynamics.Sampling sites were selected in each the third level aquatic eco-functional zoning in Fan river basin and the purpose was to contrast the characteristics of macroinvertebrates community structure and functional properties in each aquatic eco-functional zoning. Benthic macroinvertebrates communities in three functional regions showed significant difference and demonstrated consistency with habitat conditions, human activities and other factors in each eco-functional zoning. The result showed that benthic macroinvertebrates could be used to verify the rationality of aquatic eco-functional zoning.