Complex tactics in a dynamic large herbivore–carnivore spatiotemporal game

Abstract

The spatiotemporal game between predators and prey is a fundamental process governing their distribution dynamics. Players may adopt different tactics as the associated costs and benefits change through time. Yet few studies have investigated the potentially simultaneous and dynamic nature of movement tactics used by both players. It is particularly unclear to what extent perceived predation risk mediates the fine‐scale distribution of large and dangerous prey, which are mostly driven by bottom–up, resource‐related processes. We built habitat use and movement models based on 10 years of monitoring GPS‐collared grey wolves Canis lupus and plains bison Bison bison bison in Prince Albert National Park, Canada, to investigate the predator–large prey game in a multi‐prey system. Bison did not underuse patches of high‐quality vegetation at any time during the seasonal cycle even though wolves were selectively patrolling these areas. Rather, in at least one season, bison engaged in complex tactics comprised of proactive responses to the long‐term distribution (risky places) and reactive responses to the immediate proximity (risky times) of their opponent. In summer–autumn, bison reduced the time spent in food‐rich patches as both the long‐term use and the immediate proximity of wolves increased. By demonstrating that wolf distribution triggers patch abandonment by bison, we provide a key element in support of the shell game hypothesis – where prey move constantly to avoid predators attempting to anticipate their location. In winter, a season of relatively high energetic stress, bison no longer abandoned food‐rich patches as predation risk increased, while no bison responses to wolves were observed in spring–summer. Our work demonstrates the highly dynamic and complex nature of the predator–large prey spatiotemporal game, a key trait‐mediated mechanism by which trophic interactions structure ecological communities.

Extensive daily movement rates measured in territorial arctic foxes

“…Predator movements generate spatial variation in predation risk that can be perceived by prey, which can further respond by modifying their behavior (Gaynor et al, 2019). Prey will for example avoid areas that are highly used by their predators (Simon et al., 2019; Valeix et al, 2009). The distance traveled by predators within their territory could have critical effects on the spatial and temporal distribution of predation risk, since a predator's movement rate strongly determines its encounter rate with prey, which in turn controls its consumption rate (Holling, 1959; Merrill et al, 2010; Pawar et al., 2012).…”

A theory of the use of information by enemies in the predator-prey space race

“…Previous theoretical (Mitchell & Lima 2002;Mitchell 2009) and empirical (Roth & Lima 2007;Valeix et al 2011;Bosiger et al 2012;Simon et al 2019) studies have suggested that predators and prey play a shell game in which both the prey and the predator would benefit from moving regularly in an unpredictable manner to prevent the other player to learn and then avoid (for the prey) or focus on (for the predator) places where the other player would be. Theoretical studies have however focused on unpredictability of the prey, as they never allowed predators to move somewhat randomly.…”

“…Empirical demonstrations of the shell game are only emerging (Simon et al 2019)(but see Laundré 2010), and the optimal level of randomness that prey and predators should optimally use remains unknown. No theory integrating the co-evolution of prey and predator movement strategies has been proposed yet, and we argue this is a fundamental gap in our ability to understand and predict the movement of animals.…”

Complex eco-evolutionary dynamics induced by the coevolution of predator–prey movement strategies

“…Behavioural traits play an important role in predator-prey interactions. Experiments have demonstrated that predators and prey show strong behavioural responses to each other (Gilliam & Fraser 1987;Savino & Stein 1989;Ehlinger 1990;Hammond et al 2007;Simon et al 2019). These responses differ across species and spatial scales, and they are likely the product of strategies that incorporate various information sources from the environment.…”