Distribution Pattern Of Aquatic Plants And Environmental Analysis In The Guo River, A Typical River In The Huai River Basin

The basin of Huai River located in the east of China and situated in the middle of the North-South climatic transition zone, which also is one of the most important base for agriculture production in China. Water system is complex in this basin and moreover, varies of wetlands are located in this basin, which providing lots of production to ensure the normal life for local people. However, due to the development of economy and increasement of people, the wetland resource in this region degradated seriously and the vegetation were destroyed significantly. Vegetation distribution patterns means the spatial position and distribution of plants, which is determined by the interactive effects of biological characteristics of plants and environmental factors. Studies on the distribution patterns of wetland plants are not only benefit for knowing the distribution status of wetland plants, but also favorable for indicating the change of eco-environment. Therefore, study on the distribution patterns of wetland plants is a hotspot in the wetland research. Aquatic plants, as the most important part of the wetland, play an important role in the maintenance of the wetland structure and the displaying of wetland functions, such as providing food and shelter for other species, stabilize sediments, etc. Therefore, clarifying the distribution patterns within its forming mechanism of aquatic plants in the Huai River basin can benefit for understanding the forming-mechanism of distritbution patterns of aquatic plants and provide theory basis for the protection of wetland resources and the restoration of the degradation wetlands. In this paper, a typical river named Guo river was choosed, based on the field investigation and indoor measurement, the distribution status of aquatic plants with the forming reasons were analysised. The results are as follows:A total of 27 species, including 10 submerged species (37%),4 floating-leaved species(14.8%),3 floating species(11.1%) and 10 emergent species(37%), belonging to 20 families,23 genera were found in the Guo river. The main floristic component of family is the type of cosmopolitan, which takes up 90% of the total families. The main floristic conmonents of genera was temperate types. The construction of Mengcheng brake had an negative effect on the diversity of aquatic plants. The species richness and diversity were significantly greater in the section of Guoyang-Mengchang than the section of Mengcheng-Huaiyuan. Environemtal factors, specially the NH4+-N and NO3-N of soil and water changed greatly among 72 plots. Along with the investigation course, from Huaiyuan to Guoyang, the conductivity of water, water depth, water transparency and total nitrogen of water increased significantly, while the total phosphorus and Ph of soil decreased significantly. The construction of Mengcheng brake is the key factors that determining these changes.Cluster analysis showed that the aquatic plants in the Guo river can be divided into 8 community types, that is community of Eleocharis congesta+Scirpus trigueter, community of S. trigueter+Alternanthera philoxeroides, community of S. trigueter, community of Ceratophyllum demersum, community of A. philoxeroides, community of Phragmites australis+A. philoxeroides, community of Nymphoides peltatum and community of Trapa bispinosa+Nuphar pumilum. CCA ordination showd that the phy-chemical characteristics of water, such as the content of NO3-N, PO4- and total phosphorus were the key factors that determining the distribution patterns of aquatic plants in the Guo river.