Biomass distribution and habitat use by forest elephants (Loxodonta africana cyclotis), Bongos (Tragelaphus eurycerus eurycerus) and Duikers (Cephaloplius spp.) in the Kakum Conservation Area
Elephants, bongos and duikers use the same patches of forest but previous studies have focused on elephants with little or no recent information on the status of bongos and duikers in Kakum Conservation Area. The objectives therefore were to estimate the number of elephants, bongos and duikers and identify the factors that underlined the distribution and use of the habitat by elephant and bongo. The size structure and biomass of the elephant population was also examined. After a reconnaissance, the study area was stratified into three (high, medium and low) density strata. By dung counts in the wet and dry seasons, the population size and biomass of elephants, bongos and duikers (Maxwell, Black and Yellow-backed) were estimated. Camera traps were also used to survey the bongo population. The elephant population size was estimated at 217 with confidence interval of 136-336. This estimate is close to an estimate obtained from a previous genetic survey of the population, when the dung data was analyzed using a model that relates the number of dung piles on the forest floor to rainfall in the two months preceding the survey. Fewer bongo droppings (<7) were recorded in each season during the dung count. Bongo photographs were not obtained through the camera traps and an estimate of bongo numbers could not be made. But through inferences from the dung count, the camera traps results and from a predicted camera trapping success, a conservative density estimate of 0.10 bongos/sq km in the high density zone is presented. The bongo population was discrete and isolated. Maxwell and black duikers densities were estimated at 9.61 and 2.20 sq/km respectively. No Yellow-backed duiker dropping was seen in the dung count. All elephants irrespective of age group were potential crop raiders. There was no marked difference when the dung boli circumference data of the elephant population in the park and their crop raiding counterparts were compared. Sub-adult elephants made the highest contribution to the dung boli records and dominated the estimated biomass. Elephant abundance and distribution was influenced by gaps in the forest canopy and fruiting tree spots. But there was a threshold of fruit abundance (approx. 2.80 fruiting tree spots/km) beyond which elephant dependence declined. A weak relationship exists in the sharing of food resources between elephants and bongos. It is suggested that there is no strong competition between the two species at their current densities. The park staffs have always said that poachers are less active in the wet season because they would be tending their farms but their assertion was not supported by the study, so anti-poaching efforts must be intensified in the wet season. Farmers also maintained that killing elephants will keep them off the crop fields but illegally killed elephants in the study area within three months to the dry season survey did not significantly influence the distribution of the elephants.
A thesis submitted to the College of Agriculture and Natural Resources in partial fulfilment of the requirements for the degree of Master of Science