Data Set: Body size and vegetation greenness shape activity patterns of ungulates in semi-arid African savannas

Species captures lists the camera trap records for each species at each location. Linear Model Variables lists the inputs required to run the linear model, including predictor variables.

Abstract: Flexibility in ungulate behaviour allows their persistence in environments with varying threats and constraints. We explored the relationship between activity patterns and body size of ungulates in the highly seasonal, semi-arid Kalahari, with the aim to identify drivers influencing their diel cycles. Using camera traps and the Watson’s U2 test, we compared the activity patterns of four ungulate species ranging in body size from the steenbok (Raphicerus campestris, 11 kg), springbok (Antidorcas marsupialis, 27 kg), gemsbok (Oryx gazella, 162 kg) to the eland (Tragelaphus oryx, 393 kg). Our linear model showed that vegetation greenness (Enhanced Vegetation Index) and the magnitude of difference in body size were important predictors of ungulate activity. Ungulates more similar in body size had similar 24-hr activity patterns when vegetation greenness was relatively high (gemsbok vs springbok U2 = 0.028, coefficient of overlap = 0.9, 95% CI: 0.78 – 0.98; springbok vs steenbok U2 = 0.066, coefficient of overlap = 0.85, 95% CI: 0.71 – 0.95), but distinctly different 24-hr activity patterns during periods of reduced vegetation greenness (gemsbok vs springbok U2 = 3.171, coefficient of overlap = 0.6, 95% CI: 0.53 – 0.66; springbok vs steenbok U2 = 0.612, coefficient of overlap = 0.59, 95% CI: 0.46 – 0.73). Neither steenbok, nor eland, changed their activity patterns when vegetation greenness was reduced, while springbok and gemsbok became more crepuscular and nocturnal respectively. Ungulate activity patterns in the hot and semi-arid Kalahari may therefore be influenced by resource competition, mediated by ungulate body size and changes in vegetation greenness.