Facing escalating biodiversity decline, threats extend beyond species loss to reduced evolutionary and functional potential in ecosystems. Urbanisation is one of the main causes of biodiversity loss, and its impact is expected to be further increased by the anticipated growth in the human population over the coming decades. In this context, achieving sustainable development requires a balance between conservation and urban growth. A key step in characterizing the impacts of urbanisation on biodiversity using integrative approaches that reflect current scenarios of global change. This study focuses on the main representatives of urban flying vertebrates, birds and bats, to study how different levels of urbanisation affect these components of biodiversity. More precisely, we examine the influence of Urban Heat Islands (UHIs), as a proxy of strong urbanisation, on community composition and taxonomic, phylogenetic and functional diversity of bats and birds in the French city of Poitiers. We also assess the contribution of turnover and nestedness to community composition. Our results indicate that high urbanisation, reflected by UHIs, affects community composition, particularly for bats, whose diversity across taxonomic, phylogenetic and functional components is reduced. In contrast, birds display only a decline in taxonomic diversity in these zones. Turnover is the dominant process structuring bird communities, whereas nestedness primarily drives bat assemblages, suggesting greater potential for species replacement in birds. These results highlight the differing vulnerability of birds and bats to urbanisation and emphasize the need to consider these differences and the ecological interactions between them in conservation and urban planning strategies.
Querejeta et al. (Fri,) studied this question.