Investigation And Analysis Of Vascular Plants In Caizi Lake Wetland

The Caizi Lake Wetland is located in the middle way of the three major migratory routes of migratory birds in China and the East Asia-Australia Waterbird Migration Channel which is one of the major migration routes for the migratory birds in the world.It provides important wintering sites and migratory resting places for migratory birds such as bean Anser fabalis and Cygnus columbianus in East Asia.It is one of the wintering grounds of Grus monacha and Ciconia boyciana,a threatened species in the world.Recognized as an important ecologically sensitive area and a key area of biodiversity in the world,Caizi Lake wetland plays an important role in flood storage,water-logging prevention,climate regulation,biodiversity protection and water purification.Furthermore Caizi Lake provides the important value for scientific research education and the ecological protection.This survey uses 3S technology,using the method of cross-sectional investigation and sample-square investigation.The present situation of vascular plant resources in Caizi Lake wetland has been found out at a preliminary stage.The floristic composition,geographical composition,alien invasive species,vegetation types and distribution of vascular plants in Caizi Lake wetland are analyzed in the paper.It provides the necessary basic data for the protection of vascular plant resources in the Caizi Lake wetland as well as for wetland ecosystem protection of Caizi Lake.The influencing factors to the change of vascular plant in Caizi Lake wetland are analyzed and specific suggestions for restoration and protection of wetland in Caizi Lake are also presented for the purpose of providing scientific basis for better protection of ecological environment and overwintering waterbird resources in Caizi Lake wetland.The survey results are as follows:1)Vascular plants are abundant and diverse in Caizi Lake wetland.There are 422 species belonging to 278 genera in 92 families.There are 8 species of pteridophytes,8 genera and 7 families of pteridophytes,2 species of 2 genera and 1 family of gymnosperms and 412 species of angiosperms belonging to 268 genera and 84 families.There are 10 species of aquatic plants,8 species of floating leaf plants,9 species of floating plants and 12 species of submerged plants,totally 39 species of aquatic plants.2)There are 13 genus distribution types of wetland plants in Caizi Lake wetland.The vascular plants in Caizi lake wetland show the universal law of wetland vegetation with the largest proportion of widespread species.At the same time,it also shows obvious concealment and the dual nature of tropical and temperate zone.3)There are only 6 species of national key protected plants in the Caizi Lake wetland,and 1 endemic genus in China.The national key protected species of vascular plants in Caizi Lake wetland are scarce,the endemic genera are scarce,and the individual characteristics of plant flora in the wetland are not obvious.4)The threat to the Caizi Lake Wetland ecosystem is increasing gradually.Alien invasive species Alternanthera philoxeroides and Ambrosia artemisiifolia have affected the living space of native plants.Conyza canadensis and Eichhornia crassipes has formed a dominant community in the Caizi Lake Wetland.Other invasive alien species,such as Pharbitis nil,Pharbitis purpurea,Sorghum sudanense,Lolium temulentum and so on,have shown the size of diffusion.5)Vegetation in Caizi Lake wetland is divided into 3 types,6 vegetation subtypes and 24 communities.The plant community of wetland grass has the absolute predominance.In spring,the main dominant species are Ranunculus polii and Potentilla supina.In summer,the main dominant species are Setaria viridis and Eleusine indica.In autumn,the main dominant species are Hemarthria altissima and Polygonum criopolitanum.In winter,the main dominant species are Carex thunbergii and Carex cinerascens.6)Compared with the historical data,the species and distribution area of aquatic vegetation in Caizi Lake Wetland have significantly decreased,and submerged vegetation almost disappeared completely.The main factors contributing to this phenomenon are fencing fishery industry and water conservancy projects.