Studies On Plant Diversity Of Urban Lake Wetland In Wuhan

Species composition,types of wetland plant communities and distribution were analyzed in this article,based on a comprehensive survey for the vascular plant in 26 typical urban lake wetlands in the main urban and the suburbs in Wuhan.The relationship between plant diversity and human interifernce were discussed,spatial distribute regularity of typical wetland plant communities along the moisture gradient were analyzed.The major threats faced by urban lake wetland vegetation were discussed,and some suggestions were made in order to protect wetland plant diversity and wetland resources.The main results as followed:1.There are 361 vascular plant species(including variation),which belonges to 231 genera and 82 families,including pteridophyte 5families,5genera,6species; gymnosperm 2families,3genera,3species;angiosperm 75families,223genera, 352species in Wuhan urban lake wetland.Compositae,Gramineae,Cyperaceae and Leguminosae are dominant families,and it is more evenly dispersed that species distributed in the level of genera.2.Herbage plant is the dominant life form,among which,annual herb,perennial herb and aquatic herb respective occupied 37.4%,32.7%and9.3%respectively.Tree species is a predominant part in cultivated species.There are 164 species of mesophyte which is the most,accounting for 45.4%.As moisture to be a dominant ecological factor,the typical vascular plants of wetland comprise137 species,which constituted by hydrophyte,hygrophyte and helophyte,occupied 38.6%.It is indicated that the resources of wetland species were abundant in kind.3.Analysis on geography flora of genera showed that the cosmopolitan type, tropical type and emperate type were dominant in genera of wetland vascular plant. Metasequoia glyptostroboides which belongs to China endemism type have been found in Wuhan lake wetland.4.31species(15 families,23genera)of exotic plants have been found in wuhan lake wetland,24 species of which belongs to alien invasive species,occupied 77.4%in the total exotic plants,the remainder mainly comprise cultivated species by human being introducted,such as Taxodium ascendens,Robinia pseudoacacia,Trrifolium repens, etc.The survey on exotic plant showed that alien invasive species distributed widely around the lake shore in Wuhan.They had become a critical threat to the community structure of protosomatic wetland vegetation and biodiversity.5.The number of species have obviously positive correlation with area and perimeter of the lakes,compared with the value of correlation(r) between area and perimeter,perimeter is more remarkable,while the number of species seemed not simply increased with area or perimeter of the lakes.Analysis showed that agriculture activities,constructions around lakeshore and intense human disturbance caused the differences of plant diversity and the degeneration of vegetation in urban lake wetlands. 6.Species diversity index have positive correlation with dominance index of wetland plants,while no significant correlation was observed between species richness and species diversity index.Based on species richness,diversity index, evenness index and ecological dominance of wetland plants,proportion of typical wetland plants in various species of wetland plants,species richness and ecological dominance of typical wetland plants,26 lakes were classified into 4 categories, adopted the method of system cluster.7.Yanxihu lake,Qingtanhu lake,Yandonghu lake,Chedunhu lake,Beitaizihu lake have full natural vegetation and less human interference.Huangjiahu lake,Zhuzihu lake,Yehu lake,Wujiahu lake had been interferenced by agriculture activities,while the condition of vegetation was still in a higher level.Damage to the wetland vegetation to some extent in Donghu lake,Tangxunhu lake,Wuhu lake,Qinglinghu lake,Nanhu lake,etc,because of shoreline artifical and water contamination. Vegetation of wetland had been degenerated singnificantly in Shahu lake and Neishahu lake.8.Wetland vegetation in Wuhan urban lake wetland was divided into 5 vegetation types,that is Woody swamp,herb swamp,emergent hydrophytes,fioating hydrophytes and hydrophytes vegetation,in which Ass.Nelumbo nucifera,Ass.Zizania caduciflora, Ass.Alternanthera philoxeroides,Ass.Paspalum paspaloides,Ass.Cynodon dactylon, Ass.Roegneria kamoji,Ass.Imperata cylindrical etc.were the most common association types in Wuhan lake wetland.9 Spatial distribute regularity of typical wetland plant communities along the moisture gradient was analyzed,case study in Yandonghu lake.In the perennial seeper ecological environment,preponderant vegetation is Typha angustifolia community,it has clear hiberarchy in vertical direction.In the seasonal seeper ecological environment,preponderant vegetation is Juncus effusus +Carex neurocarpa community,that was typical wet herbaceous association,and have no evidently vertical hiberarchy.In wet surface environment,Imperata cylindrica community was preponderant vegetation,which species composition was similar with Com.Juncus effusus +C.neurocarpa,while significant differences in important value and frequency of species.In the rather dried ecological environment,preponderant vegetation was Imperata cylindrica community,tree and shrub gradually appeared, such as Broussonetia kazinoki,Rosa multiflora,Rubus coreanus,etc.Analysis showed that the species richness,species diversity index and dominance index of plant community in seasonal seeper ecological environment was higher than other habitats communities.