Study On The Relationship Between Urban Forest Structure And Urban Birds In Autumn

Urban forest is an important part of urban ecosystem,and its structure is the basis for realizing its ecological function.Urban birds,as the most common wild animals in cities,are an important part of urban biodiversity and an important indicator species for evaluating regional environmental quality.In order to optimize the urban forest structure and improve the ecological service function of fragmented urban forest patches.Taking urban birds as indicator species,21sample plots of 0.5-2.5hm~2 in the First Ring Road of Hefei City and its adjacent areas were selected to investigate the urban forest structure and bird data.Combining Arc GIS software with satellite image map,the indexes of urban forest tree species composition,space,infrastructure and landscape structure were quantified.Taking the richness,abundance,Shannon index and Pielou evenness of urban birds as indicators,referring to the definition of urban forest in a narrow sense,the relationship between the structure of 20 urban forest sample plots and bird habitat was expounded by using correlation analysis,principal component analysis and regression analysis.The research results show that:(1)There are 662 trees,573 shrubs,214.5m2 hedgerows and 46.3 m2 herbaceous groundcovers in 21 plots,belonging to 51 families,76 genera and 90 species.Palm,osmanthus,Cinnamomum camphora,Ligustrum lucidum,Koelreuteria paniculata,Lagerstroemia indica,Broussonetia papyrifera,Pomegranate,Pittosporum and Cedar are the most widely used trees and shrubs.After nearly 20 years'development,the DBH of urban forest trees in Hefei has increased significantly,and the overall tree height remains at the level of medium and small trees.Large trees are scarce.The tree species with large DBH and tree height are mostly Metasequoia glyptostroboides,Ginkgo biloba,Cedar,Chinese tallow and Cinnamomum camphora.On the landscape structure,the total area of urban forest patches in the outer ring area of Hefei surrounded by Linquan Road,Qianshan Road,Wangjiang Road and Tongling Road is about 432hm2,and the d IIC value and d PC value of each land are low,which makes little contribution to the overall landscape connectivity of the region.(2)A total of 8 orders,22 families and 38 species of birds were recorded in the survey of birds in the sample plot,accounting for 10.08%of the recorded bird species in Hefei,and1213 birds were counted by the maximum retention method.The Palaearctic species and Oriental species of birds permeate each other,and the proportion of insectivorous birds and omnivorous birds is as high as 76%.According to the definition of dominant species,Bulbulwark(19.37%),Magpie(12.04%)and Tree Sparrow(11.38%)are the dominant species of urban birds,which are omnivorous and clustered birds.The similarity of bird composition in 20 urban forest sample plots ranged from 0.381 to 0.857,with an average value of 0.588,showing high similarity.(3)Species composition,space,infrastructure and landscape structure of urban forest have different influences on bird index.By further analyzing the influencing factors,the factors affecting bird richness can be classified into three aspects:the amount of resources and potential available resources in urban forest sample plots,the richness and diversity of trees,and the resource enrichment degree of urban forests per unit area.The factors affecting bird abundance can be classified as the comprehensive influence of landscape structure characteristics inside urban forest and the factors outside urban forest structure,and the influence on Shannon index and Pielou evenness of birds is that besides the site structure characteristics,external factors still play an important role.The equation of bird abundance and bird abundance is obtained by stepwise regression:a:Y(BR)=0.399*TR+0.005*TD+3.176*AR+0.755BR:bird richness(species);TR:tree richness;TD:Tree density;AR:Area rangeb:Y(BA)=30*AR-0.945*RER+73.26BA:Bird abundance;AR:Area range(ha);RER:Road enclosing rate(%)...