Blue-green infrastructures as avian refuges: Evidence from thermal-habitat niche stability across seasons

Many biodiversity trends have been linked to climate and land-use changes, but their effects on local community dynamics at fine regional scales remain underexplored. This study investigated urban blue-green infrastructure's impact on community niche variability, focusing on ecological source areas in Jiangsu, China. We analyzed bird communities' thermal and habitat niche compositions during breeding and overwintering seasons, influenced by climate and habitat variations. The results indicated that ecological source areas provided significant microclimatic buffering, attracting more cold-dwelling species during the breeding season, while warm-dwelling species dominated the overwintering season (p < 0.0001). Furthermore, the range of habitat niches remained consistently broad throughout all seasons (p < 0.0001). Blue-green infrastructure components differed in their composition across seasons in their effect on local and landscape-scale thermal and habitat niche compositions of bird communities. At a landscape scale, the number of patches influenced thermal niche metrics and significantly affected community niche breadth across several scales. Increased wetland area and the number of patches extended a variety of ecological niche types at almost any scale and season, while increased forest area and aggregation benefited certain species with specialized needs. These results indicated the importance of high-quality blue-green infrastructure management and planning to effectively support diverse conservation strategies. It is vital to employ these approaches to combat extreme climate and land-use changes as well as to develop novel adaptation strategies for communities. A biodiversity conservation strategy based on high-value typical BGI areas, ecological nodes, and ecological corridors is expected to promote sustainable development.