Study On The Landscape Pattern Of Green Land Semi-natural Community In Shanghai New Jiangwan City Conservation Area

With the accelerating development of urbanization,the original vegetation of the city is gradually disappearing and deteriorating.The original natural landscape in the city is gradually disappearing.In this paper,we study the semi-natural community of the green space in the preservation area of Shanghai New Jiangwan City,take all the plants in the sample as the research object,and study the characteristics of the semi-natural community from the perspective of the structure,biodiversity,and landscape effect of the sample community.The application of semi-natural communities in cities.At the same time,the concept of semi-natural is clarified,and a breakthrough for the development of a semi-natural concept in the direction of the landscape is sought,adding a landscape type concept to the landscape industry in the future.The main conclusions are as follows:(1)Important species value:The species with the most important values in the current conservation area sample are:coral,palm,privet,arborescens,heather,horse chestnut,scorpion,locust,broad-leaved Stones,Ophiopogon japonicus,and rice straw.In woody species,the important values of Cyclobalanopsis glauca and Castanopsis kawakamii are low,and the herbaceous species are rich in species,so the overall important values are relatively average.(2)Types of community greenland:The community types of greenbelts in Xinjiangwancheng Conservation Area are dominated by deciduous broad-leaved forests,supplemented by evergreen and deciduous broad-leaved mixed forests,and there is a small amount of deciduous coniferous forest communities.(3)Characteristics of vertical structure of the community:The community can be vertically divided into the upper,middle,and lower layers of the trees;the upper and middle layers of the shrubs;and the herb layer.Among them,the upper middle layer of the trees was the best,and the number of species in the lower layers of trees and shrubs was the highest,and the lower layers of shrubs were loose.In addition,in the large sample of Phyllostachys pubescens,the number of other species in the whole community except for Phyllostachys pubescens is too small,and the density of bamboo is relatively large.The problem of bamboos needs to be solved urgently.(4)Characteristics of community diversity:Diversity of green space in the conservation area of Xinjiangwan City Compared with the ordinary urban forest park,the Simpson index and Shannon-Wiene index of the shrub layer in the tree layer were significantly higher than those in the urban forest park,and the herb layer Simpson index and Shannon-Wiene index is not very different.The evenness index of the arbor layer,shrub layer and herb layer in the preservation area of the New Jiangwan City generally exceeded 0.8;the evenness index of the arbor layer and shrub layer in the urban forest park was seriously low.The conservation area is superior to the ordinary urban forest park in the performance of the diversity index,thus ensuring the stability of the community structure and avoiding the phenomenon of community decline or death caused by climate change.(5)Plant species screening:After investigation,it was found that the plant species of the semi-natural community in Xinjiangwan City are dominated by native tree species,and the tree species with high important value are basically zonal species;therefore,when we screened for the species of urban semi-natural communities,the plants The species range is dominated by zonal vegetation species,and species with good growth and good landscape effect,such as herbaceous plants,are selected from the zonal vegetation.At present,species of weed species in the conservation area are more invasive,and we can artificially plant some areas.Herbal plants with ornamental characteristics,such as grasshoppers,crow's petals,oil grass,iris,lisianthus,etc.These are wild and slightly shade-tolerant herbs.(6)Community screening and landscape effects:After investigation and analysis,we obtained that in the semi-natural community of Xinjiangwan City,the typical communities are:coral and tree structure,Ligustrum lucidum,camphor tree,and hackberry communities;Tree + tree formation community;Coral Park + camphor community;Metasequoia community;Coral community.From the above communities,we can infer that the species of coral,privet,citron,eucalyptus,arboreal,and esculin are all zonal vegetation,and the advantages of zonal vegetation have been proved on the side,and a stable community can be built..At the same time,the viewing characteristics of the same genus are basically the same,and we can carry out screening combinations from the same genus.For example,the genus Euphorbia is a genus of deciduous trees and autumn leaves are yellow.The camphor trees,the Shenshui River,the Zhejiang Water Stream,and the Putuo Mountain under the Auraceae branch are all evergreen trees.When we create the desired landscape,we can replace it according to the principle of selection:zonal vegetation species with similar ornamental characteristics in the same family or in the same genus.To achieve the goal of enriching urban biodiversity.