The response of ungulates to rainfall along the riverbeds of the southern Kalahari, 1972-1982.

Abstract

Examined springbok Antidorcas marsupialis, gemsbok Oryx gazella, blue wildebeest Connochaetes taurinus and red hartebeest Alcelaphus buselaphus. Springbok reacted most rapidly to rainfall along the riverbeds and, by browsing in dry times, maintained a fairly stable presence throughout the year, although the actual number present in any one year was dependent on annual rainfall. Gemsbok responded more slowly, and reached highest numbers in years of high rainfall when grasses were tall and mature, after which they rapidly departed from the riverbeds. Red hartebeest also reached their highest numbers during the rainy season, but departed slightly more slowly than gemsbok. In dry years, they too failed to come into the riverbeds. Blue wildebeest in the vicinity of the riverbeds tended to be more sedentary than the other species. The presence of potable artificial water appeared to be more important for wildebeest and, although rainfall was undoubtedly an important factor in regulating numbers along the riverbeds, they depended to a greater extent on breeding success and mortality factors than on emigration and immigration. The overall seasonal pattern of ungulate abundance along the riverbeds in the southern Kalahari was one of wet season concentrations and dry season dispersion. -from Authors springbok Antidorcas marsupialis gemsbok Oryx gazella blue wildebeest Connochaetes taurinus red hartebeest Alcelaphus buselaphus