Changes in diversity of wetland birds across spatial scales following 20 years of wetland degradation: a case study from central Türkiye

OpenAlex İngilizce

Wetlands, despite their ecological value, have been extensively degraded worldwide. This study investigates the impact of 2 decades of wetland degradation, uncontrolled water use, and warming on the taxonomic and functional diversity of wetland bird communities in the Konya Closed Basin, Türkiye. Using data from 2 breeding bird atlases (1998 and 2018) and historical satellite imagery, we assessed changes in wetland breeding bird diversity across various spatial scales and wetlands’ seasonal shrinking patterns. We partitioned beta diversity into its turnover and nestedness components and calculated individual contributions of extinctions and colonizations to the overall changes in beta diversity. We utilized mixed-effect models and Wilcoxon tests to assess the significance of diversity changes. Our findings revealed widespread diversity losses at the local scale. We also found that the communities became more dissimilar, primarily because of local diversity losses. At the basin scale, functional diversity decline (66%) greatly exceeded taxonomic diversity decline (19%). Our satellite imagery analysis revealed an advancing wetland shrinking/drying over the study period. The diversity changes we found indicate that functional homogenization occurred at local and basin scales, and diversity losses at the local scale caused a subtractive heterogenization among the communities. We suggest that advancing wetland shrinking/drying dates due to climate change and human actions may be contributing to the decline of the late-breeding endangered diving ducks. Taken together, these findings suggest that a large-scale conservation plan, considering these seasonal and spatial changes, is needed to protect the remaining wetland bird diversity in the basin.