Effects of Environmental Changes on the Assemblages of Eight Sympatric Large Grazers in the Mole National Park, Ghana

Abstract

The goal of this thesis was to determine the effects of environmental changes on the assemblages of eight sympatric large grazer~ of Mole National Park (MNP). Transects were surveyed in each of five main habitat types over a one-year period by counting large grazers and measuring abiotic, anthropogenic and grass-related variables. Climate and land cover data time series were analysed for change detection and ARIMA models used to forecast changes up to 2020. Mixed effects and regression models of grazing behaviours were used to identify the environmental factors by which animals selected preferred feeding areas. The results indicated there has been a significant climate change over the period. The mean temperature increased by about 0.7 °c after two decades and the mean rainfall decreased after each decade. Co-existing large grazers avoided resource use overlaps and competition, but allowed high overlaps and some degree of competition when resources were limited. Larger grazers were more selective for forage than smaller ones and habitat use varied seasonally with different patterns for each habitat type leading to inter-habitat shifts by large grazers. The mean density of grazers ranged from 1.18 ± 0.36 (elephant) to 6.5 ± 0.601km2 (kob). Populations showed increasing trends for all the large grazers with the potential for further increases in future. With the weight ratio of 1.40, grazers at MNP were closely packed but several species with similar body weight co-existed within the grazer assemblage. Limiting factors, mainly water, fire and anthropogenic, imposed constraints that resulted in either lack of a clear pattern of abundance, distribution and habitat selectivity or unexplored forage in most seasons. Replication of this study about two to four times is recommended to boost the outcome as information for management planning and action.