Ecological Community Construction Based On The Plant Dispersal Pattern And Its External Impact Factors In Beijing Greenway

The rapid development of economy and the continuous expansion of urbanization have led to the serious fragmentation of the landscape.As a linear corridor,the greenway has played a compensatory role in the loss and fragmentation of habitat and brought connected benefits,but unreasonable plant design will cause the rapid spread of invasive plants in green corridor as well.Based on the location type of greenway in Beijing,this paper selected 18 green ways as the research object,and adopted the ecological community investigation method to survey the data of cultivated plants and spontaneous plants,including plant species,plant height,crown width,plant quantity,cover degree and so on.The data were statistical analyzed in order to explore the distribution pattern and the influencing factors of the plants spread by different media in the green channel,and to construct the ecological community models suitable for application in Beijing.The main results show that:(1)A total of 484 plant species(including mutation)belonging to 264 genera and 91 families were recorded in Beijing greenway,including 96 kinds of trees,67 kinds of shrubs,308 kinds of herbs,7 kinds of wood vines,2 kinds of bamboo,4 kinds of pteridophytes.Among them,there were 228 species of cultivated plants(including mutation)belonging to 127 genera and 57 families,and 364 species of spontaneous plants(including mutation)subordinating to 224 genera and 78 families.(2)In the aspect of artificial plant landscape among different types of greenway,108 cultivated plants were investigated in the city park-ring greenway,109 species of cultivated plants in the central city waterfront greenway,88 species of cultivated plants in the country leisure ring greenway,65 species of cultivated plants in the forest park ring greenway,83 species of cultivated plants in the east wing river greenway and 78 species of cultivated plants in the northwest wing scenery greenway.With respect to the vertical structure of the cultivated plant communities,the city park-ring greenway,the central city waterfront greenway and the country leisure ring greenway were richer in structure,dominated by the combination structure of trees brushes and grasses.In the aspect of the crown density,the central city waterfront greenway,the east wing river greenway and northwest wing scenery greenway were relatively high.According to the conservation and management of cultivated communities,the level of the central city waterfront greenway and the central city waterfront greenway ranked higher.(3)A total of 189 species of animal dispersal plants including 68.75%of native plants were recorded in the greenway of Beijing,which covering 12 types and 5 variant types of plant flora and mainly dominated by North Temperate,Widespread and Pantropic;and 215 species of wind dispersal plants including 69.3%of the native plants were concerned,covering 12 types and 5 variant types of plant flora and North Temperate,Old World Temperate and Widespread accounted for the main part.(4)In the aspect of spatial diffusion pattern,the spatial distribution of the animal dispersal plants diversity and the wind dispersal plants diversity were both obvious different,and the distribution pattern of the wind-diffusing type was more significant.The diversity index of the spontaneous plants located in the north and the west sides of the greenway was higher,especially in the north-south direction.With the resection of the quad away from the fitness trail,the plants diversity showed a downward trend,indicating significant divergent interference effect(edge effect increased,landscape fragmentation intensified).Amongst the seasonal dynamics,the spatial distribution of the animal dispersal groups decreased in spring and autumn,and the population gradually moved to the inside of the green channel;the seasonal dynamic fluctuation of the wind diffusion group was smaller,while the divergent interference effect was most significant in summer.(5)Amongst the influencing factors,there was a significant positive correlation between the species diversity of the animal spread plants and the greenway width,the urbanization gradient,the diversity of the birds,the altitude,etc,and the population was significant negative correlated with the diversity of cultivated community,besides it showed obvious difference among the different groups of vertical structure of cultivated community,habitat type and conservation management grade.There was a significant positive correlation between the species diversity of the wind-diffusive plants and the stratification and elevation of the urbanization,the altitude and so on,and it was significant negative correlated with the diversity of the cultivated population,in addition,wind dispersal plants diversity is obvious different among the groups of the greenway type,the cultivated community structure,the habitat type,and the conservation management.(6)A total of 34 species of invasive plants were recorded in Beijing greenway,covering 7 types and 2 variant types of plant flora,which were dominated by Widespread,North Temperate and Pantropic.The distribution trend of species diversity of invasive plants was similar to that of wind dispersal groups,but it showed obvious adaptability of animal propagation in spring and autumn,and the distribution pattern was close to the animal dispersal plants.There was a significant positive correlation between the spread of invasive plants and the urbanization gradient,which was negatively correlated with the greenway width,greenway construction age,crown density and altitude.(7)According to the above research results,three ecological community types were proposed for the ecological community model.1)Diffusion-restricted communities.This type emphasizes the green landscape function,the spread of spontaneous plants is limited;2)Diffusion-dominated communities.This type is designed to promote plant proliferation,meanwhile,play the landscape function;3)Invasion-resisted communities.This type inhibits the intrusion of alien species with intrusion threat,and weakens the landscape function.Ultimately according to the function of different types of community put forward design principles and recommended the plant community model.Based on the ecological investigation and community census,this study is aim to explore the design method of ecological greenway in Landscape architecture by using the theory of Community ecology,Plant movement ecology and Species genetics,etc.The distribution pattern and its influencing factors in the green road were analyzed in this paper.According to the above research conclusion,the paper put forward the design principle and the patterns of the ecological community suitable for the Beijing area,and lays the theoretical foundation for the popularization of the ecological greenway.