Study On The Diversity And Community Characteristics Of Wetland Plants In The Nansihu Basi

As one of the top ten freshwater lakes in China,Nansi Lake is the largest freshwater lake wetland in North China region.It is also a water conveyance channel and an important water storage reservoir for the East Route of South-to-North Water Transfer Project.The health of its ecosystem is directly related to the quality of water delivery.The wetland vegetation in this area greatly affects the health of the water environment,and can provide living environment and food sources for other organisms.Therefore,the study on plant diversity and community ecology of wetland vegetation in Nansi Lake basin can provide background information for local ecological protection and high-quality development,and it is of great significance for maintaining the multifunction of ecosystems and protecting and restoring wetland ecosystems.Through field investigation,layout of quadrats,collection of specimens,and careful identification,the list of wetland wild plants is constructed,and the plant resources and flora in this area is analyzed.According to the information of field investigation sample plots,the plant communities are classified by TWINSPAN,and the vegetation in this area is divided into different types of clusters.By comparing theα diversity of plants,the distribution of plant communities in different lakes and communities is explored.The main results of this paper are as follows:1.There are 85 families,250 genera and 437 species(including subspecies and varieties)of wild plants in Nansi Lake basin wetland.The dominant families in this area are cosmopolitan family.The analysis of family and genus composition shows that although there are abundant plant groups in this area,the degree of species differentiation is low,the flora is relatively young,and the ecological environment is fragile,the diversity of species composition coexists with instability.2.Compared with the historical list of Nansi Lake wetland,the author find 69 species of plants newly recorded in the geographical distribution of Nansi Lake,belonging to 28 families and 55 genera,such as Juncus gracillimus,J.taonanensis,Carex raddei,Cyperus compressus,C.odoratus,etc.5 species of newly recorded plants were recorded in Shandong.There are Teucrium japonicum,Euphorbia makinoi,Commelina diffusa,Fagopyrum dibotrys and Echinochloa glabrescens.3.By analyzing the geographical elements of families and genera,the flora in this area is dominated by temperate elements,followed by tropical elements.The flora is characterized by the transition from tropical to warm temperate.Compared with the flora of nearby lakes and wetlands,the higher the latitude,the higher the temperate nature of vegetation.The results of FER cluster analysis indicate that the study area is the closest to the flora of Hongze Lake.4.The vascular plant resources in this area are mainly medicinal plants,followed by forage plants.There are abundant species resources of vascular plants.There are four species of plants listed in the "National Key Protected Wild Plants List".They are Ceratopteris chingii,C.thalictroides,Glycine soja and F.dibotrys.There are 28 species of invasive alien plants,which have seriously affected the growth of other local species.There are six plants on the Priority Management list of invasive Alien species.They are Phytolacca americana,Alternanthera philoxeroides,Cabomba caroliniana,Erigeron canadensis,Avena fatua and Solidago canadensis.5.The wetland vegetation community in Nansi Lake basin is divided into 26 types by TWINSPAN classification.The species composition and structural characteristics of each cluster are discussed.The plant distribution in the wetland community of Nansi Lake tributary is zonal with the change of soil moisture gradient and flooding condition.The main communities on both sides of the tributary are Ass.Phragmites australis+Symphyotrichum subulatum and Ass.P.australis+ Paspalum distichum+ S.subulatum.The plant community types distributed in Nansi Lake area are diverse,and the emergent plants are mainly Phragmites australis,Typha angustifolia and Nelumbo nucifera.Free floating plants are mainly Trapa natans and Nymphoides peltata.Floating plants are generally Spirodela polyrhiza,Hydrocharis dubia and Salvinia natans.The submerged plants are mainly Ceratophyllum demersum,Myriophyllum spicatum,Stuckenia pectinate and Potamogeton crispus.The DCA ranking showed that vegetation distribution was closely related to environmental water conditions.6.The species diversity in the tributaries of Nansi Lake is higher than that in the lake area,and the evenness of vegetation distribution in the lake area is higher than that in the tributaries.By comparing the species diversity indices of different regions,it was found that the Hanzhuang Canal and Liangji Canal among the tributaries had the highest species richness and diversity,followed by Si River,and Guangfu River and Baima River are the lowest.Hanzhuang Canal and Liangji Canal had the best species evenness,Si River followed,Lao Wanfu River was the worst,and other rivers had similar species evenness.Among the Nansi Lakes,Zhaoyang Lake had the highest species richness,followed by Weishan Lake,while Nanyang Lake and Dushan Lake had low species richness.The species diversity of Zhaoyang Lake,Nanyang Lake,Weishan Lake and Dushan Lake in descending order.The species evenness of Nanyang Lake,Dushan Lake,Weishan Lake and Zhaoyang Lake in order from high to low.By comparing the species diversity in the tributaries,the species diversity in the tributaries was significantly higher than that in the lakes.The degree of species diversity can reflect the community habitat status and species distribution in the region.The higher the species diversity,the more complex the environment,and the relatively stable community structure.Therefore,there are abundant wetland plants in Nansi Lake basin,but it still exists problems of ecological fragility.In order to protect the wetland ecology of Nansi Lake,the author puts forward some suggestions from the aspects of early warning and prevention of alien invasive species,protection of national key protected wild plants and pollution prevention.