RESULTS
Population size and density
The total mean number of gelada in the Kotu forest was 229 ± 6.11. They were 259 ± 6.77 and 198 ± 5.44 individuals of gelada during the dry and wet seasons, respectively. There was significant variation in population size between wet and dry seasons (U= 1330.0, P= 0.001). The mean population density of gelada in the study area was 16.63 ± 2.21 individuals per km2 (Table 1). The population density of gelada was 14.41 and 18.85 per km2 during the wet and dry seasons, respectively.
Age and sex structure
Out of the total mean number of 229 ±6.11 individuals of the gelada encountered in the study area, females comprised 121± 18.8 (52.84 %) individuals and males 69± 5.0 (30.13%) individuals, whereas 39 individuals were juveniles with undetermined sex (Table 2). The number of females was significantly higher than males (χ2= 14.23, df= 1, P= 0.000). There was higher number of female individuals during dry (140 ± 16.10) season than the wet season (102.0± 13.10). Out of the total mean individuals of geladas recorded in the study area adult, sub adult and juvenile constituted 113 (49.34%), 77 (33.62%) and 39 (17.03%) respectively. The adult: subadult: suvenile ratio is 2.8:1.9:1.
There was a significant difference in age/ sex classes in the population of geladas (F 4 20 =7.279, P= 0.001). The population was dominated by adult females (75 ±10.90), while sub adult males (31 ± 1.75) were least represented (Table 2). Adult females comprised the highest proportion of geladas during both dry (86 ± 2.67, 33.20%) and wet (64 ± 1.88, 32.32%) seasons (Table 2). On the other hand, sub adult males comprised the least proportion of geladas during both dry (32 ± 1.02, 12.36%) and wet (29± 0.86, 14.64%) seasons (Table 2). There was a significant difference of age/ sex classes during both wet (F4 20 = 4.948, P= 0.006) and dry (F 4 20= 4.948, P= 0.000) seasons. The mean male to female sex ratio was 1:1.78. The average ratio of adult male to adult female was 1:1.96 (Table 3).
Group size and composition
The mean group size of gelada was 18± 2.0, out of which 2.5± 0.5 (13.89%) was all- male unit (AMU) and 15.5± 1.5 (86.11%) was one male unit (OMU) social system. During the wet season, 16 groups were encountered, out of this 2 (12.5%) was AMU (bachelor and sub adult male) and 14 (87.5%) was OMU social system. During the dry season, 20 groups were recorded, out of which 3 (15%) was AMU and 17 (85%) was OMU social system.
The average maximum group size of AMU was 11.5± 0.5 and the average minimum group size was 3.5± 0.5. During the wet season, the maximum group size of AMU was 11 and the minimum was 4. Whereas, during the dry season, the maximum group size of AMU was 12 and the minimum was 3. On the other hand, during the dry season, the maximum group size of OMU was 17 and the minimum was 6. Whereas, during the wet season, the maximum group size of OMU was 13 and the minimum was 7. The average band size was 45.0± 2.53. The band size during the wet season was 2-4 adult male geladas with their follower up to 60 individuals aggregated together. On the otherhand, during dry season, the band size and compostion comprised, most of a time 2- 8 adult males with its follower maximum up to 110 individuals of geladas.
Population distribution pattern
Populations of gelada were not uniformly distributed over the study area among doimant habitat types. The highest number of gelada was observed in grassland habitat 68± 8.0 (29.87 %), while the least were recorded in plantation forest habitat 34 ± 4.5 (14.74%) (Table 4). Simlarly, the highest density of geladas was recorded in grassland habitat (4.96 ± 0.56), while the least was in plantation forest (2.45 ± 0.29) (Table 1). There was significant difference in the number of geladas among habitat types (χ2= 15.913, df= 4, P= 0.003). Significant variation in the number of geladas was observed among habitat types during both wet ( χ2=14.980, df= 4, P= 0.005) and dry (χ2=17.699, df=4, P=0.001) seasons. During the wet season, 16 groups of geladas comprising 198 individuals’ were recorded in Kotu forest (Fig. 3). Out of these, the highest number of groups 5 (31.25% were recorded from grassland habitat and the lowest groups 2 (12.50%) in the plantation forest (Fig. 3). During the dry season, 20 groups comprising 259 individuals were recorded. During the dry season, the maximum numbers of group 6 (30.0%) were recorded from grassland habitat and the minimum group number 2 (10.0%) from natural forest.