A neglected wetland in human-dominated landscape shields avifauna from seasonal harsh conditions in Gambella, western Ethiopia

To mitigate biodiversity loss, increasing the number of protected areas in terrestrial and marine habitats is becoming a pressing demand on a global scale. However, the rising human population and per capita consumption continue to limit protected area designations, especially in economically productive areas. There is a dearth of information on the potential roles of small wetland ecosystems in human-dominated landscapes in supporting biodiversity conservation efforts. Here, we assess the roles of wetland ecosystems for avifaunal diversity within Gambella National Park and in the surrounding human-dominated landscape. We used a strip transect method to collect data on bird species during the wet and dry seasons. We evaluated whether each bird species are migratory or resident based on Birdlife International category and assessed their conservation status based on IUCN Red List of Threatened Species. We recorded 114 bird species belonging to 41 families and 16 orders from the study area. Though the overall diversity of birds is significantly higher within the national park when averaged over the two seasons (p = 0.001), we recorded higher species diversity (3.78 vs. 3.09), evenness (0.85 vs. 0.77), and richness (88 vs. 56) for the wetland located within the human-dominated landscape during the wet season. The reverse was true during the dry season where we recorded higher diversity (3.29 vs. 2.31), evenness (0.75 vs. 0.55) and richness (80 vs. 66) for the wetland located within the national park. Species turnover between the two areas was higher during the wet season than during the dry season (β = 0.22 vs. 0.1), showing the avifaunal similarity shared between the two systems seasonally fluctuates. Most bird species often depend on the wetlands outside protected areas for feeding and roosting in the wet season to escape widespread flooding within the park. Our results support synergy between the two settings for sustaining avifaunal diversity, illustrating the importance of near-natural ecosystems within human-disturbed landscapes for supporting biodiversity conservation efforts. Besides focusing on protected areas alone, conservation agencies and decision makers should take into account the significances of such areas in human-dominated landscapes to ensure comprehensive and sustainable biodiversity conservation.