Avian Conservation and Ecology (Jun 2021)
Local habitat and landscape attributes shape the diversity facets of bird communities in Inner Mongolian grasslands
Abstract
The loss and fragmentation of natural habitats because of anthropogenic activities are major threats to biodiversity worldwide. In recent decades, vast mosaics of natural and seminatural habitats have been transformed into fragmented agricultural landscapes in Inner Mongolia, China, with potential negative effects on avian diversity. We quantified the effect of local and landscape habitat attributes on the taxonomic, functional, and phylogenetic diversity of bird communities in Inner Mongolian grasslands. We considered eight independent habitat variables obtained by variance inflation factor analysis. We used canonical correspondence analysis to determine how these habitat factors of multiple scales explained variance in species composition. We then fitted Bayesian generalized additive models to analyze the habitat-biodiversity relationships and included a smooth effect of land cover richness to test the intermediate disturbance hypothesis in each model. Our results provided evidence that differences in bird assemblages can be explained, in part, by differences in local and landscape-scale habitat features. The responses of the four diversity indices to these predictors were diverse and scale-dependent. We found species richness and Shannon diversity exhibited similar response, with both being negatively related to bare land percentage while being positively related to plant canopy and impervious surface percentage. Phylogenetic diversity was positively associated with plant richness while negatively associated with forest percentage and impervious surface percentage. We found no statistical evidence for a relationship between functional diversity and any of the variables examined here. Additionally, for the four measures of bird diversity, we did not find any evidence that they peaked at intermediate levels of habitat disturbance. We propose that assessments of regional grassland bird communities should be conducted at multiple scales and that a range of biodiversity metrics are required to better evaluate and inform conservation decision making, especially when the target is preserving not only species but also their evolutionary history and ecological functions.
