Population structure and distribution of geladas (Theropithicus gelada, Ruppell 1835) in Kotu Forest, Nor thern Ethiopia

Endemic gelada populations outside protected areas are less investigated and population census data are not available. As a result, a study was conducted to investigate the population size, structure and distribution of geladas in Kotu Forest and associated grasslands, in northern Ethiopia. The study area was stratified into five dominant habitat types namely; grassland, wooded grassland, plantation forest, natural forest and bushland based on dominant vegetation type. Each habitat type was further divided into blocks and a total counting technique was employed to count the individuals of gelada. The total mean population size of gelada in the Kotu Forest was 229 ± 6.11. The mean ratio of male to female was 1:1.178. The gelada age composition comprised: 113 (49.34%) adults, 77 (33.62%) sub-adults and 39 (17.03%) juveniles. The mean number of group one male unit (OMU) ranged from 1.5±0.2 in the plantation forest to 4.5±0.7 in the grassland habitat.  On the other hand, all male unit (AMU) social system group was recorded only from grassland (1.5) and plantation forest (1) habitats.  The average band size (number of individuals per band) was 45.0± 2.53. The largest number of geladas was recorded from grassland habitat 68 (29.87%) and the lowest from plantation forest habitat 34 (14.74%). Even though, the sex ratio was female biased, the proportion of juveniles to other age classes was very low as compared to geladas in relatively well-protected areas, indicating negative consequences for the future viability of the gelada populations in the area. Geladas were widely distributed over open grassland habitat. Therefore, for sustainable conservation of the geladas in the area, there is a need for integrated management of the area with special attention on the conservation of the grassland habitat.