| The blue-green space composed of green land and water provides various types of regulation and support services for the city.The typical ecological effects of blue-green space include the impact on bird diversity.This study selected south lake catchment area in wuhan with continuous canopy plaque area gradient 12 green space as the research object,extracted from habitat level and landscape level,landscape and urbanization interference variables as environment variables is analyzed,and the 2021-2022,spring,summer,autumn,winter four seasons on the investigation of distribution of the sample patches in birds,The environmental variables were screened and grouped by principal component analysis,and the species composition and distribution characteristics,species diversity and functional diversity of bird communities in built environments around urban lakes were quantitatively analyzed,as well as their relationships with key environmental variables.The environmental factors that have significant influence on different bird ecotypes were screened through redundancy,and the influence trend of key environmental variables on bird diversity of different ecotypes was analyzed.In this way,the paper explores the spatial optimization strategy of environmental green space built around urban lakes,and provides an important theoretical and practical basis for the construction of urban environment for harmonious coexistence of humans and birds.The main research results are as follows:(1)Through the analysis of the species composition and temporal and spatial distribution characteristics of birds in the built environment around the South Lake,the results showed that in the built environment around the city lake,rare species and rare species were more inclined to natural forest land and park green land in spring,summer and autumn,and forest birds and insect-eating birds accounted for a larger proportion.At the same time,larger green patches showed higher bird aggregation and bird diversity,which had better characteristics of protected bird species composition.There was no obvious advantage in bird diversity in adjacent water patches,but some bird species showed a clear preference for adjacent lake patches.However,due to the influence of urbanization disturbance variables,the bird community in the green patches of residential areas with greater disturbance tended to be homogenized,and omnivorous birds had more obvious advantages in the community,while widespread birds had obvious numerical advantages in the community.In spring,summer and autumn,the bird community preferred natural woodland and park patches.In winter,the bird community weakened its preference for land use type and distributed evenly in all kinds of urban green patches.In residential green patches,the bird community cluster phenomenon was obvious,with a large number of birds,and the advantage of widespread birds was obvious.(2)Through the analysis of the impact of built environment around urban lakes on bird species diversity and functional diversity,the results showed that the impact of environmental variables on bird communities could be divided into four categories by principal component analysis,which were landscape level feature factors,dynamic type disturbance factors,site level feature factors,and traffic disturbance factors.(3)Through the analysis of the correlation between bird diversity and environmental variables(landscape variables and urban disturbance variables)in the built environmental green space around the South Lake,the analysis results at the landscape level show that DN has no significant effect on the three ecotypes of birds;In the NS threshold range of800 m,natural woodland was more attractive to widespread birds.The results at the habitat level showed that the effect of LSI on bird diversity was always accompanied by the effect of CA.When LSI > 750,the ABUb of widespread birds increased significantly,and the numerical dominance in the community was more significant.The richness of both widespread birds and forest birds increased with the increase of CA,and the functional richness of widespread birds reached its peak when CA=13.The influence of urbanization disturbance variables on bird community is two-sided.The increase of state disturbance factors(200%＿Y,NT)will lead to the gradual homogenization of bird community,and forest and water birds are more susceptible to the negative impact of 200%＿Y.The widespread bird community can better adapt to the impact of the rise of 200%＿Y,and gradually occupy a more significant advantage in the community.In addition,when 200%＿Y=0.4,the negative effects on forest birds and water birds are more significant.When 200%＿Y=0.37,widespread birds occupy a significant numerical advantage in the community.The negative impact of NT on urban bird community was different in autumn and winter.In autumn and winter,the negative impact threshold range of NT was 400 m and 200 m,respectively.The dynamic disturbance factors(PF,NI)would further increase the dominant position of widespread birds in the community.Widespread birds were less affected by NI,water birds had an upward trend with the increase of NI,and forest birds had a larger fluctuation range.The ABUb of widespread birds and waterbirds increased with the increase of PF.When PF=6,the abub of widespread birds reached the peak value,but the abub of forest birds was not affected by PF.Therefore,the increase of urbanization disturbance variables within a certain range can increase the number of widespread birds and strengthen the dominance of widespread birds in the community,but it does not mean the increase of biodiversity and ecological function of bird community... |
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