Density, Detection Function, and Abundance of Black and White Colobus Monkey (Colobus guereza) in Khatasa Protected Forest, Amhara Regional State, Ethiopia

Khatasa Protected Forest is one of the protected forests found in the Awi Zone of Amhara Regional State that has been protected since 1994. The study on the population distribution of the Colobus monkey ( Colobus guereza ) was carried out from January 2021 to August 2021. For this purpose, a line transect survey was established using a stratified random sampling procedure based on their vegetation types. Distance software, Version 7.3, was used to analyze the abundance and density of Colobus monkeys. For data analysis, the conventional distance sampling model with hazard rate key function and simple polynomial adjustment was employed. The detection function of the Colobus monkey during the dry season showed that the Hazard rate key function model parameters A (1) and B (1) were positively correlated ( r = 0.791 and 0.681, during dry and wet seasons). The model took the lowest Akaike information criterion (AIC) values of 282.2 and 260.20, during the dry and wet seasons, respectively. The total number of Colobus monkeys in the study area was 229 during the dry season and 183 during the wet season, respectively, while the sex ratio of Colobus monkeys in the study area was 1:2.9. The AIC value gives us the relative measure of fit or model performance, and the test indicates that the data were normally distributed and fitted to the selected model of analysis (Kolmogorov–Smirnov test [ p = 0.74] and Cramer–von Mises family tests [ p = 0.70] during the dry season and [ p = 0.80]) during the wet season, respectively. Determining the population status of monkeys in dry and wet seasons in this protected area would enable to take conservation actions.