Antipredator response diminishes during periods of resource deficit for a large herbivore

Abstract

2019. Antipredator response diminishes during periods of resource deficit for a large herbivore. Ecology 100(4):Abstract. The starvation-predation hypothesis predicts that, during resource shortages, prey forego antipredator behavior and forage as much as possible to avoid starvation, even when risk of predation is high. We tested this hypothesis using GPS locations collected simultaneously from moose (Alces alces) and wolves (Canis lupus) in the Greater Yellowstone Ecosystem of North America. We assessed shifts in the speed, displacement, and habitat selection of moose 24 h following encounter with wolves (0-1,500 m distance). We examined whether the strength of antipredator behaviors would weaken as winter progressed and the nutritional condition of moose declined. Moose responded to wolf encounters by increasing their rate of movement in early winter, but only within 500 m distance. Importantly, these responses attenuated as winter progressed. Moose did not avoid their preferred foraging habitat (riparian areas) following encounters with wolves at any distance, and instead they more strongly selected riparian areas, especially in early winter. Our findings support theoretical predictions that resource deficits should dampen prey antipredator behavior, and suggest that nutritional condition of prey may buffer against run-away risk effects in food webs involving large mammalian predators and prey.

Effects of Human Disturbance on Terrestrial Apex Predators

“…This case provided a remarkable example of the effects of losing predators in nature, to the extent that "the reintroduction of gray wolves to Yellowstone National Park is the most celebrated ecological experiment in history" [44]. Research carried out in this ecosystem in the last two decades explores, among other things, the relative impact of predation in terms of numerical and behaviorally mediated effects on both mesopredators and prey [44][45][46][47][48][49][50], which is further complicated by the modulating effects of climatic factors [33,51].…”

Roads, forestry, and wolves interact to drive moose browsing behavior in Scandinavia

“…The trade‐off between predation avoidance and foraging has long been recognized (Sih 1980, McNamara and Houston 1987). Predation and foraging are dynamic processes that vary in time and space, and their effects are context and scale‐dependent (Oates et al 2019). The risk allocation hypothesis states that predation risk and food availability interact: under food‐limited conditions, animals will lose fat faster and enter risky areas earlier than in areas with abundant food (Lima and Bednekoff 1999).…”

Remote mapping of foodscapes using sUAS and a low cost BG-NIR sensor

“…A modified BG-NIR camera, mounted on a low cost sUAS, has been shown to be successful in classifying plant species and to describe the foodscapes of ungulates such as Ibex. The benefits of this study, the methodology presented, and the potential for further development are applicable to studies of wild and domestic herbivore distribution and welfare, predator distribution, vegetation changes, and habitat biodiversity internationally (Boulanger et al, 2018;Moore et al, 2010;Oates et al, 2019;Peters et al, 2019;Searle et al, 2007) Further studies with hyperspectral cameras are necessary to assess the improvements hypothesised, and the potential enhancement of efficiency and accuracy offered by an increased quantity and refined nature of spectral information.…”

“…The spatiotemporal assessment of food resources for large herbivores, also called foodscapes, is fast gaining interest within landscape and wildlife management, and associated research agendas worldwide. Knowing the distribution and availability of specific plants (i.e., used by ungulates see Espunyes et al, 2019), has become essential not only to understand population dynamics of herbivores but also those of their predators (Oates et al, 2019;Peters et al, 2019;Searle et al, 2007). Mapping vegetation is also essential for ecologists (Moore et al, 2010) and wildlife conservation agents (Schweiger et al, 2015a).…”