Influence of temperature and predation risk on herbivore micro habitat choice in a South African savanna

Sammanfattning: The challenging conditions animals face on the African savanna influence their time budget. To accomplish the activities needed for survival they have to trade-off the amount of time they can invest in each activity. One well studied example is the trade-off between foraging and avoiding predators. Another trade-off is between avoiding predation and heat stress. In the face of climate change escaping high temperatures is an important behavioural response in animals. Between March and June of 2016 the trade-off between perceived predation risk (with visibility as a proxy) and heat stress was examined for mammalian herbivores (with a focus on ungulates) in Hluhluwe-Imfolozi Park, South Africa. The woody vegetation was manipulated in experimental plots to create a difference in visibility, and animal visitation was recorded through camera traps. The difference in woody vegetation was also predicted to affect temperature which was measured in all plots via Thermochron iButtons. Four species; impala (Aepyceros melampus), white rhino (Ceratotherium simun), plains zebra (Equus quagga), and blue wildebeest (Connochaetes taurinus) had enough visitation data for analysis. Impala visitation increased with increasing visibility, and impala showed a temporal avoidance of high temeratures. White rhino visitiation on the other hand was not influenced by visibiliy, but was positively related to average maximum temperature. The results show that perceived predation risk affect micro habitat choice in animals, and that they respond to high temperatures. These findings are important for managing animal populations on the African savanna, especially when concidering the future ramifications of climate change.