Effects of Wind Farm Development on the Vertical Distribution Patterns of Mountain Birds in Karst Regions

With the rapid development of China's wind power industry, its ecological impacts have drawn increasing research attention. Karst mountainous regions, recognized as global biodiversity hotspots, have undergone extensive wind farm development. However, the effects of wind power construction on the vertical distribution patterns of mountain birds remain poorly understood. In this study, bird communities inside and outside operational wind farm areas were surveyed in the Karst mountains of northern Liuzhou, Guangxi, to assess wind-farm impacts on avian diversity and vertical distribution patterns. The results revealed that mountain bird species richness within wind farm areas followed a unimodal pattern along the elevational gradient, while richness outside wind-farm areas declined monotonically along the elevation gradient. This indicates that wind farm disturbance has altered the vertical distribution of bird communities. Both α-diversity and functional diversity peaked at mid-elevations within wind farm areas, and species turnover between low- and high-elevation communities was significantly higher, suggesting that mid-elevation zones may act as critical ecological transition belts for the mixing and dispersal of bird species across elevations. Furthermore, functional diversity patterns indicated that wind farm development increased environmental filtering effects on bird communities at high elevations, where raptors exhibited clear avoidance behavior toward turbine areas. These findings underscore the importance of prioritizing ecological conservation for mid-elevation zones within wind farm regions and avoiding wind farm planning for elevations with peak biodiversity.