Study On Spatial Heterogeneity Of Water Environment And Its Influence On Aquatic Plants Communities In Huaihe River Basin(Henan Section)

Huaihe River Baisn is one of the most serious polluted basins in China. The destruction of water environment has severe impacts on aquatic ecosystem, which lead to reduce of the aquatic organism, it also endanger the water ecological safety and river health. Over the years, Henan section hydrographic net is the most serious polluted area in the Huaihe River Baisn. Thus, it is important to investigate the water environment and the present situation of aquatic biological resources spread in huaihe river basin(henan section).In the huaihe river basin(henan section),the research on spatial heterogeneity of water environment and its effect on the distribution of the aquatic plants has great significance for the recovery of aquatic ecosystems.Based on the wild investigation on aquatic plants and laboratory analysis on river sediment and water, this article use the methods of principal component analysis, cluster analysis, geology-statistical analysis and the Nemerow method to evaluate the spatial heterogeneity of water environment and its influence on the community distribution of aquatic plants. The main results are as follows:(1)The results of principal component analysis show that the TP, PO4--P, NH4+-N and TN of water, NH4+-N and TN of sediment are the key factors that determine the water environment.(2)The results of Cluster Analysis which based on 144 sampling points shows that the water environment of South tributaries is better than the north tributaries in the Huaihe river basin(southern reaches of Huaihe river), and mainstream of Huaihe, Shayin river, Hong river and Guohe river are better than its branches, and middle and upper reaches of river is better than lower reaches.(3)The results of GIS geostatistical analysis on the spatial heterogeneity of water environment show that Jialu river, Guo river, Hong river and the middle and lower reaches of Ru river and Lv river are the most serious polluted areas, meanwhile, the upper and middle reaches of Shayin river, Zhugan river, Huang river, Bailu river, Shi river and Guan river have a better water environment.(4)Wild investigation shows that a total of 51 aquatic macrophyte species were detected, including 28 emergent species, 12 submerged species, 10 floating-leaved species and 1 floating species. These aquatic plants can be classified into 14 communities. Form.Alternanthera philoxeroides, Form.Ceratophyllum demersum, and Form.Hydrilla verticillata have more appearance frequency than other species, each accounts for 25.7%, 12.5% and 11.8%. Submerged species Ceratophyllum demersum and emergent species Alternanthera philoxeroides, Phragmites australis,Polygonum flaccidum have better adaption capability, they are polluton-resist species. Different aquatic plants communities distribute differently. Submerged plant communities mainly distribute in the upper and middle reaches, the south tributaries of Huai He River, the Shayin River, Hong River, which have better water environment, however, emergent plant communities can distribute in the areas which have a poor environment.CCA ordination reveals that water environment factors, such as TP, PO4--P, NH4+-N concentrations, were the key factors that determine the distribution of aquatic plants in Huaihe River Basin.