Habitat associations and structural connectivity shaping avian diversity in southern Ethiopian forest mosaics

Understanding patterns of avian diversity and habitat associations is fundamental for biodiversity conservation in fragmented tropical landscapes undergoing rapid environmental change. This study evaluated bird species richness, abundance, seasonal variation, and habitat associations across four habitat types (grassland, shrubland, natural forest, and plantation forest) within the Gamuwa and Woyito forest mosaics of southern Ethiopia. Bird surveys were conducted using line transects and point-count methods during the wet and dry seasons. A total of 71 bird species representing 33 families and 11 orders were recorded, including endemic, migratory, and globally threatened species. Forest habitats consistently supported greater species richness, diversity, and abundance than open habitats, whereas grasslands exhibited the lowest diversity. Bird abundance differed significantly among habitats and between seasons. Although overall diversity was slightly higher during the dry season, this pattern is likely attributable to seasonal differences in bird detectability, vegetation phenology, and localized resource availability rather than reflecting a general ecological trend. Species similarity was highest between natural and plantation forests, suggesting that these habitats share comparable bird assemblages. Because landscape connectivity was not directly quantified, these results indicate potential structural connectivity rather than functional connectivity within the forest mosaic. Overall, the findings demonstrate that heterogeneous forest mosaics provide complementary habitats for forest-dependent, endemic, and migratory bird species and emphasize the importance of landscape-level conservation strategies for maintaining avian diversity in southern Ethiopia.