Effect of drought on wildlife activity at artificial waterholes

Abstract

Across southern Africa artificial waterholes have been introduced into many national parks to reduce the pressure of water scarcity on animals during drought. However, their introduction can shift ecological dynamics, and many artificial waterholes are now being removed. As global temperatures rise, droughts are predicted to become more frequent and more severe. Whether to retain or remove artificial waterholes thus presents a management dilemma. Here, we examine the effect of an extreme drought on artificial waterhole use in the Kruger National Park, South Africa. Comparing camera trap data collected during a one-in-twenty year drought with observation from a non-drought year, we quantify shifts in waterhole visitation patterns between years. The majority of the species show differences in waterhole use between drought and non-drought years. Species showing the largest temporal shifts include kudu and white rhinoceros, whereas elephants and warthogs show little change between years. Temporal overlaps between species pairs were also highly shifted, with the majority of species overlapping more in drought years, although some (e.g. buffalo and impala) show the opposite trend. Asynchronous shifts in species daily activity cycle may have cascading impacts on interspecific competition, predator-prey interactions, and multi-host disease dynamics. Our study illustrates how the interaction between drought and management choices to mitigate impacts of climate change may have complex and unforeseen ecological consequences. We show that, during drought, artificial waterholes are visited more frequently, likely increasing the frequency of interspecific interactions, including between ungulate herbivores and their predators, and elevating risk of disease spillover. HIGHLIGHTS • Drought and extreme heat events are predicted to become more common, with cascading impacts on species ecologies. • Artificial waterholes are a feature of many parks in Africa and can mitigate the impact of severe droughts on wildlife. • The decision to maintain or remove artificial waterholes from national parks presents a complex management dilemma. • Using camera trap data, we examine how extreme weather (drought and heat) may shift species waterhole visitation patterns. • We show changes in timing of waterhole visitation during drought which results in greater temporal overlap among species.