Short-term response in ungulate numbers to rainfall in the Nossob river of the Kalahari Gemsbok National Park

Abstract

Counts of springbok, gemsbok, red hartebeest and blue wildebeest were made in the Nossob riverbed of the Kalahari Gemsbok National Park to measure the response in abundance of these species to the onset of the summer rains. Springbok and red hartebeest showed an immediate increase in numbers, probably in response to improving grazing as the first green sprouts of the riverbed vegetation appeared. Gemsbok showed a delayed reaction, their numbers increasing only after the vegetation in the riverbeds grew tall enough to be utilized by them. Blue wildebeest showed a relatively small decline in numbers which could be due to local movements or the start of their annual east-west movement in winter.