Introduction
The diurnal large mammals have a special role in maintaining important ecological healthy functions of terrestrial ecosystems and are good indicators of the habitat value (Estes et al. 2011). Particularly, the large predators often shape the population size, distribution, and behavioral activities of the prey population (Berger et al. 2001); and the large herbivores act as ecological engineers by changing the structure and species composition of the vegetation (Dinerstein 2003). Beyond the direct species interaction, the mammalian species manipulate the whole ecosystem through cascading trophic effects (Berger et al. 2001; Crooksand Soule 1999).
The high diversity of large mammals is a natural feature of the African tropical savanna biomes and the present distribution of such species within the topographically diverse Rift Valley region of the East African savanna (Turpie and Crowe 1994).
Understanding the distribution, abundance, and habitat requirements of mammalian species is basic to establish a baseline for its long-term monitoring at a particular site. Even though high mammalian species diversity is present in Ethiopia, its mammalian species are extremely declining, and there is little information about the mammalian resources (Girma et al. 2012). Nech Sar National Park is one of the protected areas in Southern Ethiopia which was thought to be home to a variety of wildlife including large mammals (Vreugdenhil et al. 2012). Nevertheless, only very little published information exists about large mammalian species.
Therefore, the present study aimed to assess the population size and distribution of diurnal large wild mammals along systematically laid transects in the study area. It will strongly believe that, contribute in the filling of some information gaps and significant to provide the current information on the large mammals for the strong management actions in the park area.