Supplementary material for the Israel Journal of Ecology and Evolution: Differential avifaunal diversity and water quality analysis in various sampling sites on Lake Tana in Ethiopia

The physical and chemical parameters of habitats are known to influence the populations of both migratory and resident bird species. Nevertheless, research on the impacts of water quality parameters on avian diversity and abundance within the Lake Tana biosphere reserve remains limited. The present study investigated spatial and temporal relationships of water physicochemical parameters at different sites based on anthropogenic disturbance, namely, urban, cultivar, grazing, and island sites with bird diversity, abundance, and distribution, using the point count method. A total of 209 bird species from 60 families and 21 orders, including 47 migrants, nine threatened species, and five endemic species, were recorded. Our findings show that avifauna diversity and abundance are lower in disturbed urban and cultivated habitats that exhibit elevated levels of suspended solids (SS) and turbidity, along with the lowest recorded levels of dissolved oxygen (DO) and pH, indicating that the Lake Tana biosphere reserve is in poor health. Species richness and abundance exhibited a positive correlation with both pH levels and DO. The findings showed that anthropogenic factors adversely affected the physicochemical parameters at the selected sampling sites to a varying degree. Across sampling sites, the mean spatial and seasonal pH measurements remained within the acceptable range, tending alkalinity, which is conducive to the majority of aquatic biota. The study highlights the necessity for effective management strategies focused on enhancing water quality and reducing the effects of anthropogenic disturbances to secure the long-term sustainability of the Lake Tana ecosystem and its avian biodiversity. Moreover, the presence of threatened, endemic, and migratory species, such as Necrosyrtes monachus, Gyps africanus, Aquila rapax, Clanga clanga, Balearica pavonina, Oxyura maccoa, Bostrychia carunculata, and Agapornis taranta emphasizes the importance of avifaunal conservation in Lake Tana and its surrounding habitats.