Bird Diversity And Its Influencing Factors In Nanjing City Parks

Habitat loss,fragmentation and decrease of habitat quality caused by urbanization have led to a dramatic decline in biodiversity worldwide.For highly urbanized areas,parks have become “islands” or habitat fragments for wildlife.As an important indicator group of urban ecosystem health,the response of birds to urbanization has attracted the global attention of ecologists.Understanding the key factors affecting bird diversity in urbanized environment is crucial to the protection of biodiversity in urban ecosystems.However,up to now,there is still a lack of research on taxonomic,phylogenetic and functional diversity in birds and their influencing factors in Nanjing,a city with a high degree of urbanization.In this study,we systematically analyzed the taxonomic,phylogenetic and functional diversity of birds and the effects of park characteristics on the different diversity indices in Nanjing urban parks.We first used the line-transect method to survey birds in 37 urban parks in Nanjing from April 2019 to January 2020.We also measured a number of park characteristics(area,isolation,environmental noise,building index and habitat diversity)that are commonly assumed to influence bird diversity.We then used the information-theoretic multi-model inference approach to determine which park characteristics had significant impacts on bird species richness,phylogenetic and functional diversity.The main research results and conclusions are as follows:1.During the study period,76 bird species were recorded,belonging to 13 orders and 31 families,among which Passeriformes and resident birds were the main components.2.Park area,habitat diversity and building index were important factors for bird species,phylogenetic and functional diversity in Nanjing urban parks.Among them,habitat diversity and park area were positively correlated with bird diversity,while building index was negatively correlated with bird diversity.By contrast,park isolation and environmental noise had little or no influence on bird diversity.3.The phylogeny and functional structure in urban bird communities tended to be clustered,which indicated that environmental filtering might play a major role in structuring communities.4.Our study highlights the importance of park size,habitat diversity,and building index in determining bird diversity in Nanjing city parks.Therefore,we recommend that conservation priority should be given to large parks with complex and diverse habitats or reducing the construction(e.g.buildings,roads)around parks to increase bird diversity in urban ecosystems.Our research not only analyzed the important factors affecting bird biodiversity in Nanjing urban parks,but also enriched the theoretical basis of urban bird diversity research,which provided a scientific basis for bird biodiversity protection in urban environment and urban park planning and management.