Urban green infrastructure affects bird biodiversity in the coastal megalopolis region of Shenzhen city

Urban green infrastructure (UGI) is an important habitat for birds and acts a leading role in bird diversity conservation. However, the response of bird diversity to UGIs characteristics have not been well understood. Taking Shenzhen as an example, a dataset of bird records was compiled by several citizen science. We quantified the impact of environmental characteristics of UGI on bird diversity by the generalized additive model. Then, the clustering method was used to classify bird diversity bundles for identifying priorities of UGIs. The results showed that: (1) There are significant differences in urban gradients formed the spatial pattern of bird diversity. (2) There was mainly nonlinear relationship between the bird diversity and UGI environmental characteristic, with different response processes and thresholds. Area of UGI was critical for bird diversity, and an area of about 20 km2 plays a relatively large role. Moreover, migratory birds were more sensitive to the negative impact of the surroundings of UGI, such as impervious surfaces and nighttime light. (3) The cluster analysis indicates that UGIs with better eco-environment were conducive to maintaining bird diversity. This study could be helpful to provide guidelines for the implementation of UGI planning and management and bird diversity conservation.