Factors Contributing to the Springbok Population Decline in the Kalahari, Botswana

Abstract

Nationwide aerial animal censuses of Botswana between 1992 and 2012, conducted by the Department of Wildlife and National Parks, have highlighted a 71% decline in the national springbok (Antidorcas marsupialis) population and a contraction of their range. The reasons for this decline remain unknown. We investigated possible drivers of this decline in the southern Kalahari of Botswana. We assessed springbok resource selection levels, movement behaviour and seasonal and spatial effects on the juvenile:adult female ratio. Springbok displayed high levels of forage and habitat selection. Their dependency on pan habitats renders their distribution predictable, which could expose them to high levels of predation and poaching. Springbok moved shorter daily distances during the hot dry and longer distances during wet seasons. High temperatures during the hot dry season could limit movement and prevent exploitation of spatially and temporally heterogeneous resources. We recorded a ratio of 0.37 juvenile:1 adult female in the wet season months followed by a ratio decline to 0.10:1 in the subsequent cold dry season, indicating a low recruitment rate that could be contributing to the springbok population decline. Environmental changes and anthropogenic disturbances, exacerbated by climate change, will likely exert a negative influence on selective foragers like springbok.