Figure 8 : Charcoal productions by men Figure 9 : Firewood collection by women
(Photo by Yacob Kassa, 2018)
Discussion
Large mammals’ distribution and abundance in the present study were highly associated with the habitat types. In this study, the bushland habitat has supported the highest number of mammalian species followed by open grassland, riverine forest, and ground-water forest in both wet and dry seasons. A similar result was obtained by Lemma and Tekalign (2020) in the Humbo Community Based Forest, in which the highest numbers of mammals were found in the bushland area, followed by the open grassland, while the riverine forest supported the least number of mammalian species. Whereas, the study of Chane and Yirga (2014) in Borena-Sayint National Park indicated that, woodland habitat has supported the highest number of mammalian species followed by the riverine forest and open grassland habitat, respectively. The possible reason for this distribution of large mammalian species might be due to the presence of food, and water, and stability of the area from the human disturbances. According to Tolcha et al. (2021), the availability of quality forage and other resources determines the habitat preference and association of ungulates. Large mammals in this study area had no consistent distribution among the habitat types. Therefore, their abundance significantly varies among habitats between seasons. Balakrishinan and Easa (1986) also described that water and pasture conditions or the combinations of both are the major factors determining the distribution of wildlife populations in their natural habitats.
The five large mammalian species, the Burchell’s zebra, Anubis baboon, Vervet monkey, Grants gazelle, and Colobus monkey were the most abundant in both wet and dry seasons. The Burchell’s zebra and Grants gazelle were favored in the bushland and open grassland habitats. Whereas, Anubis baboon was found in all the four habitats and, Vervet monkey and Colobus monkey were totally absent from the open and bushy grassland. This might be attributed to the feeding behavior that it is adapted to feed on a variety of food items. Kingdon and Largen (2003) described that primates commonly need forested areas with tall trees. A large number of Colobus monkey individuals were recorded in the present study from the different habitats during both wet and dry seasons. Some mammalian species including Guenther’s dik-dik, Bushpig, Abyssinian hare, and Bush duiker were the least abundant during this study. Burchell’s zebra or plains zebra was closely associated with the availability of water and edible grasses. The present study showed that plains zebra lives in areas where few other plain ungulates and livestock also depend upon. The number of individuals of Lesser kudu that was recorded in the habitats of open grassland and bushland during both seasons is comparable with the individuals recorded by Stuart and Stuart (2000). These animals had been frequently occurred in the open woodland, less frequent in the wooded grasslands, and the least observed in shrublands and open grassland areas. These animals were hardly observed in dense forests, riverine forests, and water-logged areas. The habitat choice of animals in the study area probably is a consequence of competition and predation, which allow species to coexist. The number of individuals of large mammals recorded during the wet season surpassed the number recorded during the dry season. In the open grassland and ground-water forest area was the common habitat for livestock and human encroachment, which was thought to be ideal habitat for the Burchell’s zebra and Anubis baboon species.
Gundogdu (2011) showed that livestock and human encroachments often reduce the foraging opportunities of the wild mammals, which in turn reduce the mammal’s opportunities of being sighted (Figure 10). Doku et al. (2006) recorded that, a total of 7587 heads of cattle and goats from the households in the nearby villages of Nech Sar National Park. Fetene et al. (2019) indicated that, within the Nech Sar National Park, between 2005 and 2013, the number of livestock has increased by half. Higher grazing pressure depreciates the scenery and the visibility of the wildlife species of the park (Fetene et al. 2011). Besides, firewood collection and harvesting of grasses were higher in the dry season, thus reducing the sighting of mammals. According to Fetene et al. (2019), fuelwood and construction wood gathering are also every day activities that highly have an effect on the wildlife habitats of the park. Fetene et al. (2011) also identified that grazing deteriorates the scenery and the wildlife visibility diminishing greatly over time and putting obstacles for the income-generating from ecotourism activities of the park.