Population Status, Distribution, and Threats of Colobus guereza gallarum in Bale Mountains National Park, Southeastern Ethiopia

Abstract

Colobus guereza gallarum is the subspecies of Colobus monkey (Colobus guereza) restricted to the Ethiopian highlands to the east of the Rift Valley. This study was carried out from February to June 2016 to provide data on Population status, distribution, and threats of C. g. gallarum in Bale Mountains National Park. Line transects with 5 km distance were made in all survey areas to estimate the whole population in the area. Field visits and questionnaire distribution were made to assess community perception and threats to the species. The major population of C. g. gallarum was observed in Rira. A total of 116 and 113 individuals were observed in the wet and dry seasons, respectively. There was no significant difference between wet and dry seasons (F= 0.072, df=1, p=0.795) of the population size of C. g. gallarum. Out of 229 individuals of guereza counted in both dry and wet seasons, 44 were adult males, 58 adult females, 42 sub-adult males, 43 sub-adult females and the remaining 42 were young individuals. However, as t-test indicated, here was no significant difference between wet and dry seasons in a number of in this sex and age categories (P>0.70). The male to female ratio was 1.00:1.1, while, the age ratio of young to all other individuals was 1.00:4.45. Here also, the ratio of young to an adult female was 1.00:1.40 and 1.00:1.36 during dry and wet seasons, respectively. The response of communities indicated the presence of positive perception towards the species due to its main importance for tourism and cultural aspect of the communities. Moreover, habitat destruction due to logging, farmland expansion and settlement were main observed threats to species in the area.