Effects Of Characteristics Of Landscape Structure On Bird Communities In Urban Green Spaces

Urbanization poses a global threat to birds.However,bird diversity can be enhanced in urban areas by adjusting the characteristics of landscape structures in green spaces.Therefore,understanding the variations of bird species and communities in green space sites with multiple characteristics of landscape structure can help to understand the impact of urbanization on bird diversity and contribute to the development of effective conservation strategies.Consequently,it is an open question in urban green space management how to integrate multiple green space sites with different characteristics of landscape structure from multiple perspectives to enhance bird diversity,promote the stability of bird communities,and maintain the stability of ecosystem services and functions.Based on the geodatabase of 19 green space sites and the corresponding bird survey data from March 2014 to February 2019,this study aimed to elucidate the effects of characteristics of landscape structure on bird species and communities from temporal and spatial scales within green spaces,answering the following questions:(1)What are the temporal trends and community structure of birds in urban green spaces?(2)How do characteristics of landscape structure influence the roles of different green space sites in bird species-habitat networks?(3)What underlying mechanisms contribute to the stability of bird communities when considering characteristics of landscape structure in urban green spaces?(4)Can the conservation of certain bird species lead to improvements in regulating ecosystem services,and how do characteristics of landscape structure impact these bird species in urban green spaces?First,the characteristics of the bird communities were explored using dynamic factor analysis and comparative analysis.Subsequently,ecological network analysis and regression analysis were employed to analyze the effects of characteristics of landscape structure on the role of green space nodes in the bird species-habitat network.Third,regression analysis and structural equation models were used to study the effects of landscape structure characteristics on bird community stability and to distinguish its direct and indirect effects on resident and migratory birds.Lastly,we examined the potential of bird species as surrogates for the win-win strategies of conserving biodiversity and enhancing ecosystem services,and we also explored the role of the characteristics of landscape structure of green space sites on the abundance of surrogate species.In this study,we focused on the spatial characteristics of landscape structure,which was quantified using landscape metrics.The main results are summarized as follows:(1)The density and the community structure of the forest birds exhibited noticeable seasonal variations.Notably,the species richness,species abundance,population stability,and community stability per unit hectare for resident birds were higher than those of migratory birds,and this difference was particularly pronounced during non-breeding seasons.Among these differences,the monthly average abundance of resident bird species is nearly five times that of migratory birds.Furthermore,there are variations in the community structure of bird species between forest parks,urban parks,and green belts.Bird species in green belts exhibit characteristics of high richness,abundance,and synchrony.Additionally,community stability is relatively high in green belts.(2)The species-habitat network of resident and migratory birds at the landscape level in green spaces was characterized by low connectivity,high modularity,and low robustness.Significant low-nested networks were shown in migratory birds.Furthermore,resident birds preferred to choose green spaces in areas with low urbanization intensity as their habitats,while migratory birds preferred green spaces with larger patch sizes and lower urbanization intensity.(3)Bird diversity improved community stability,while urban green spaces with larger habitat sizes,less regular shapes,and more fragmented patches had less stable bird communities.Characteristics of landscape structure influenced the stability of both resident and migratory bird communities,but through different pathways.Resident birds in urban green spaces with larger patch sizes and more irregular patch shapes had lower population asynchrony,while the population stability of migratory birds was lower in urban green spaces with less patch continuity.Additionally,patch size was positively correlated with community stability via taxonomic diversity in resident birds,while patch size and fragmentation together were negatively correlated with community stability via functional diversity in migratory birds.(4)The conservation of specific passerine bird species has the potential to achieve the win-wins for biodiversity conservation and regulating service provision.The response of bird species abundance to landscape structure characteristics in urban green spaces is species-specific,with no landscape metrics consistently affecting all species.Overall,the results revealed that maintaining a balance by moderately increasing the area,ensuring regular shape and high connectivity of habitat patches,and implementing reasonable controls on urban development intensity can enhance bird diversity and community stability in urban environments.These findings highlight the importance of considering the influence of characteristics of landscape structure on bird community from multiple perspectives,which can help conserve bird diversity in urban areas and provide theoretical bases for developing effective biodiversity conservation measures in urban green spaces.