Movement responses of an iconic large grazer to extremes of temperature and aridity

Climate change poses a threat to herbivores directly through increased thermal stress and indirectly through consequences following from altered precipitation patterns. We investigated how blue wildebeest (Connochaetes taurinus) coped with elevated temperatures and water scarcity across three regions of southern Africa differing in surface water availability. Using GPS telemetry, we tracked wildebeest movements over multiple seasonal cycles. In dry Kalahari regions, wildebeest travelled far when water sources within their usual home ranges ran dry. These animals reduced daytime movement on hotter days, especially while relocating to and from distant water sources. To compensate for consequent reductions in diurnal foraging time, they increased nocturnal activity, potentially increasing their exposure to predation risk. Conversely, wildebeest in Kruger National Park, with year-round access to surface water, showed less response in their movements and daytime foraging activity to elevated ambient temperatures. These results illustrate how lack of nearby surface water can amplify the anticipated effects of climate change on animal movements, with likely consequences for population viability. While artificially augmenting water sources through pumped pans may alleviate temperature-related stress, it can also intensify local overgrazing and attract more water-dependent species, at the expense of rarer ones. Managers must therefore carefully consider the broader ecological consequences when implementing water provision strategies to mitigate climate change impacts on wildlife populations.