Search

The resource-use patterns and nutritional status of sable antelope herds were investigated in the Okavango Delta region of northern Botswana for comparison with those documented for declining sable antelope populations elsewhere in southern Africa. GPS collars recorded the relative use of floodplain, upland and wooded grassland habitats by the sable herds while VHF beacons facilitated locating the herds for direct observations on feeding. Surprisingly, the sable herds made greatest use of upland grasslands, rather than the floodplain grasslands exposed after floodwater had receded, during the dry season months. In the upland grasslands, they exploited tall, fibrous grass species that retained quite high levels of greenness through the dry season. This ability, together with partial use of the floodplain and some browsing on new leaves and flowers, helped maintain dietary nitrogen and phosphorus levels, as indicated by faecal nutrient levels, above maintenance thresholds through the dry season. Hence, the sable herds in the study region did not seem to be limited nutritionally under the rainfall and flooding conditions prevailing during the study. [ABSTRACT FROM AUTHOR]

Animals selectively utilize their environments within a hierarchical framework. Our study addressed how the home ranges of sable antelope selectively incorporated the landscape and habitat types available to them. It was conducted in a region of northern Botswana where the sable population was expected to be thriving, in contrast to their threatened status in the wild in South Africa. The movements and habitat use of three neighbouring sable herds were recorded by global positioning system ( GPS) telemetry during parts of the seasonal cycle in a region adjoining the seasonally flooded Okavango Delta. Total home range extents covered by these herds were larger than those found for sable in other areas, and local population densities, taking into account the herd sizes, were accordingly lower than in these other areas. Access to surface water appeared to be the main limitation on seasonal home range occupation. Almost all of the local vegetation types were utilized, but sable herds generally favoured dryland grassland during the dry season and floodplain grassland during the wet season, contrary to what we had expected. Hence, it appeared that local home range occupation and habitat use by the three sable antelope herds could be influenced more by interactions with potential competitors and predators than by intrinsic habitat suitability. [ABSTRACT FROM AUTHOR]