Large carnivores make savanna tree communities less thorny
2014
Ford, Adam T. | Goheen, Jacob R. | Otieno, Tobias O. | Bidner, Laura | Isbell, Lynne A. | Palmer, Todd M. | Ward, David | Woodroffe, Rosie | Pringle, Robert M.
Understanding how predation risk and plant defenses interactively shape plant distributions is a core challenge in ecology. By combining global positioning system telemetry of an abundant antelope (impala) and its main predators (leopards and wild dogs) with a series of manipulative field experiments, we showed that herbivores’ risk-avoidance behavior and plants’ antiherbivore defenses interact to determine tree distributions in an African savanna. Well-defended thorny Acacia trees ( A. etbaica ) were abundant in low-risk areas where impala aggregated but rare in high-risk areas that impala avoided. In contrast, poorly defended trees ( A. brevispica ) were more abundant in high- than in low-risk areas. Our results suggest that plants can persist in landscapes characterized by intense herbivory, either by defending themselves or by thriving in risky areas where carnivores hunt.
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