Weak spatiotemporal response of prey to predation risk in a freely interacting system

Abstract

1. The extent to which prey space use actively minimizes predation risk continues to ignite controversy. Methodological reasons that have hindered consensus include inconsistent measurements of predation risk, biased spatiotemporal scales at which responses are measured and lack of robust null expectations.2. We addressed all three challenges in a comprehensive analysis of the spatiotemporal responses of adult female elk (Cervus elaphus) to the risk of predation by wolves (Canis lupus) during winter in northern Yellowstone, USA.3. We quantified spatial overlap between the winter home ranges of GPS-collared elk and three measures of predation risk: the intensity of wolf space use, the distribution of wolf-killed elk and vegetation openness. We also assessed whether elk varied their use of areas characterized by more or less predation risk across hours of the day, and estimated encounter rates between simultaneous elk and wolf pack trajectories. We determined whether observed values were significantly lower than expected if elk movements were random with reference to predation risk using a null model approach.4. Although a small proportion of elk did show a tendency to minimize use of open vegetation at specific times of the day, overall we highlight a notable absence of spatiotemporal response by female elk to the risk of predation posed by wolves in northern Yellowstone. 5.Our results suggest that predator-prey interactions may not always result in strong spatiotemporal patterns of avoidance.

Do prey select for vacant hunting domains to minimize a multi‐predator threat?

“…When wolves were reintroduced to Yellowstone National Park in 1995-1997(Bangs & Fritts 1996, they joined a system that was already populated by other predators of elk, including growing numbers of grizzly (Ruth et al 2019). Despite this predator diversity, subsequent research and commentary about elk space use in and around Yellowstone have assumed, implicitly or explicitly, that wolves are the only (or primary) predator that elk respond to (e.g., Ripple & Larsen 2000;Laundr e et al 2001;Creel et al 2005;Fortin et al 2005;Mao et al 2005;Middleton et al, 2013aMiddleton et al, , 2013bKohl et al 2018;Cusack et al 2019). Our study is the first to test this long-held assumption, and our results suggest it is false.…”

Density-Dependent Foraging Behaviors on Sympatric Winter Ranges in a Partially Migratory Elk Population

“…Several factors may contribute to the moderate response. First, the extent of response may reflect the frequency of reactive vs proactive responses to the risk of predation (Creel et al, 2014;Moll et al, 2017;Cusack et al, 2020). Because we used a RSFbased predation risk, that variable reflected primarily habitat conditions associated with wolves (i.e., risky places), where elk are expected to proactively make trade-offs in selection or alter their movements because of perceived vulnerability (Kauffman et al, 2007;Creel, 2018;Kohl et al, 2018).…”

Animal Welfare in Extensive Production Systems Is Still an Area of Concern

“…In the recent years, advances in tracking technology can provide a huge amount of information to better understand behavioral patterns of prey and predators. In a recent study, Cusack et al (2020) assessed the spatiotemporal response of GPS-collared female elk to the risk of predation by wolves during winter in northern Yellowstone. The study highlights a notable absence of spatiotemporal response by adult female elk to the risk of predation posed by wolves.…”