Minimizing predation risk in a landscape of multiple predators: effects on the spatial distribution of African ungulates

Abstract

Studies that focus on single predator-prey interactions can be inadequate for understanding antipredator responses in multi-predator systems. Yet there is still a general lack of information about the strategies of prey to minimize predation risk from multiple predators at the landscape level. Here we examined the distribution of seven African ungulate species in the fenced Karongwe Game Reserve (KGR), South Africa, as a function of predation risk from all large carnivore species (lion, leopard, cheetah, African wild dog, and spotted hyena). Using observed kill data, we generated ungulate-specific predictions of relative predation risk and of riskiness of habitats. To determine how ungulates minimize predation risk at the landscape level, we explicitly tested five hypotheses consisting of strategies that reduce the probability of encountering predators, and the probability of being killed. All ungulate species avoided risky habitats, and most selected safer habitats, thus reducing their probability of being killed. To reduce the probability of encountering predators, most of the smaller prey species (impala, warthog, waterbuck, kudu) avoided the space use of all predators, while the larger species (wildebeest, zebra, giraffe) only avoided areas where lion and leopard space use were high. The strength of avoidance for the space use of predators generally did not correspond to the relative predation threat from those predators. Instead, ungulates used a simpler behavioral rule of avoiding the activity areas of sit-and-pursue predators (lion and leopard), but not those of cursorial predators (cheetah and African wild dog). In general, selection and avoidance of habitats was stronger than avoidance of the predator activity areas. We expect similar decision rules to drive the distribution pattern of ungulates in other African savannas and in other multi-predator systems, especially where predators differ in their hunting modes.

Limited spatial response to direct predation risk by African herbivores following predator reintroduction

“…Indeed, where direct lion associated risk effects have been detected, lion densities have generally been much higher than the 2.1 lions/100 km 2 in our study site [Thaker et al. 2011 (5.8/100 km 2 ), Tambling et al. 2012 (13.2/100 km 2 ), Creel et al.…”

“…2009b; Thaker et al. 2011). Both of these elements of predation risk affect prey behavior because neither are homogenous across landscapes, nor are they random.…”

“…Hunting mode of the predator is one such determinant, with ambush predators exerting stronger effects than active searching predators, a pattern consistent across ecosystems, and prey functional groups (Schmitz 2008; Thaker et al. 2011; Miller et al. 2014).…”

Phantoms of the forest: legacy risk effects of a regionally extinct large carnivore

“…Whether ungulates select open or closed habitats in the presence of predators may depend on the hunting strategy of the predator (Thaker et al. 2011). Ambush predators are more likely to kill in denser habitat types (Lone et al.…”

“…2009; Thaker et al. 2011); however, information about the consequences of carnivores on the behavior and space use of their ungulate prey in heavily human‐modified European landscapes is lacking. Here, we recognize two aspects that we consider particularly relevant; prey naivety toward recolonizing carnivores, and human alterations to the perceived “landscape of fear” (Laundré et al.…”