Spatial mismatches and multi-dimensional conservation priorities for urban birds in China

With increasing urbanization, the importance of urban areas in biodiversity conservation grows. However, traditional conservation efforts are often based on high species richness, may underestimate the value of evolutionary potentials and functional traits that species could provide for the ecosystem processes. In this study, we draw priority maps to capture the priority areas of avian taxonomic, phylogenetic, and functional diversity using a relativity-based prioritization approach. We also explored possible solution for how action could be implemented in those important areas, by assessing the impacts of urbanized and environmental (climate and anthropogenic) factors on bird diversity. The results showed that only 2.1% and 6.9% overlap at the top 10% and 20% prioritization respectively across three diversity dimensions. There were significantly positive relationships between urban bird diversity and precipitation, altitude, and vegetation coverage. Conversely, impermeable surface proportion and temperature had significantly negative effects on phylogenetic and functional diversity. In addition, although little explanatory power, vegetation coverage could suppress the divergences between taxonomic and phylogenetic diversity, while tree canopy height would promote the divergences between taxonomic and functional diversity. This suggests that more vegetation coverage enables persistence of avian lineages, while different tree canopy height separates functionally similar species by offering hierarchical niches. These findings highlight the need to consider multi-dimension priorities for conservation efforts in urban areas. Moreover, better designs in greenness, such as replanting vegetation where necessary and optimizing vertical structure by well-balanced mixture of herbaceous and woody plants could be long-term measures to minimize the anthropogenic impacts on diversity loss.