Population status and habitat suitability of the vulnerable common hippopotamus (Hippopotamus amphibius) in the Dhidhessa Wildlife Sanctuary, Southwestern Ethiopia

Common hippopotamuses (Hippopotamus amphibious) are among the top five herbivorous animals in Africa. Despite being listed as a vulnerable species by the International Union for Conservation of Nature, they are a common mammal in Ethiopia's protected areas, lakes, rivers, and marshes. However, there is insufficient data to evaluate status of the population and habitat compatibility across the most of the country. The aim of this research was to ascertain the population size of hippos and the suitability of its habitat in the Dhidhessa Wildlife Sanctuary (DWS) in southwest Ethiopia. The study was conducted between 2021 and 2022. To estimate the population size, the total count procedures were employed. The adaptability of each habitat for hippos was determined using the multi-ring buffer analysis in Arc GIS 10.2. A total of 231 and 133 hippos were observed during both the dry and wet seasons, respectively. Of the surveyed individuals, 62.08 % were adults, 20.88 % were under-adults, and 17 % were young. More hippos (45.1 %) were observed in the savanna grassland during the rainy season. Subsequently, the hippos (50.6 %) relocated to the riverine forest in the dry season. Thus, the habitats in DWS and their environs were determined to range from most suitable to unsuitable for hippos. The results showed that 58.31 % of the regions were unsuitable, 18.49 % were moderately suitable, and 23.18 % were highly suitable for hippos grazing. 7.95 % of the research area slope was suitable, 26.32 % moderate and 65.72 % not suitable and 19.8 % was considered most suitable for human interference, 46.3 % was severely disturbed, and 33.9 % was moderately affected. Based on the current investigation, it has been determined that human interference in hippos' habitats is significant. In order to protect the hippos' habitats from excessive human activities and their impacts, a buffer should be created around the DWS area.