Community Structure and Floristic Compositions of Aquatic Plant Communities in the Inflowing Rivers of East Chaohu Lake and Their Relationships to Environmental Factors

Abstract

Community structure and floristic compositions of aquatic plant communities in the inflowing rivers of East Chaohu Lake was surveyed,and their relationships with environmental factors were analyzed with canonical correspondence analysis(CCA).The results showed that there were 63 species,affiliating to 54 genera in 28 families,found in the inflowing rivers of East Chaohu Lake,including 4 submersed species,3 floating specie,2 floating-leaved species,10 emergent macrophytes and 44 hygrophytes.Flora analysis revealed intrazonal feature and subtropical transition feature from tropical to Northern(N) temperate zone,with prevailing cosmopolitan,N temperate and pantropic genera components(35.19%,31.48% and 12.96%,respectively).The 54 genera of aquatic plants could be categorized into 10 areal-types.In addition,Alternanthera philoxeroides,an exotic species,growing fast and profusely,filled the river channels.In contrast,submersed macrophytes significantly declined in both species diversity and their distributions,especially in heavily polluted areas,such as the DoubleBridge River and the downstream of Xiaozhegao River.CCA analysis showed that the community structures were mainly affected by physicochemical factors rather than the water-levels.In conclusion,the inflowing rivers of East Chaohu Lake were heavily polluted,the community structure of aquatic plants was degraded,and their endemic genera were declining owning to increasing pollution.