The context dependence of non‐consumptive predator effects

Abstract

Non-consumptive predator effects (NCEs) are now widely recognised for their capacity to shape ecosystem structure and function. Yet, forecasting the propagation of these predator-induced trait changes through particular communities remains a challenge. Accordingly, focusing on plasticity in prey anti-predator behaviours, we conceptualise the multi-stage process by which predators trigger direct and indirect NCEs, review and distil potential drivers of contingencies into three key categories (properties of the prey, predator and setting), and then provide a general framework for predicting both the nature and strength of direct NCEs. Our review underscores the myriad factors that can generate NCE contingencies while guiding how research might better anticipate and account for them. Moreover, our synthesis highlights the value of mapping both habitat domains and prey-specific patterns of evasion success ('evasion landscapes') as the basis for predicting how direct NCEs are likely to manifest in any particular community. Looking ahead, we highlight two key knowledge gaps that continue to impede a comprehensive understanding of non-consumptive predator-prey interactions and their ecosystem consequences; namely, insufficient empirical exploration of (1) context-dependent indirect NCEs and (2) the ways in which direct and indirect NCEs are shaped interactively by multiple drivers of context dependence.

Prey Foraging Behavior After Predator Introduction Is Driven by Resource Knowledge and Exploratory Tendency

“…Not surprisingly, therefore, predators with large domains induced prey to spend more time searching for refugia away from the introduction quadrant and, as a result, to suffer increased penalties to consumption. Interestingly, when also considering forager memory, our findings align broadly with the "hunting mode-habitat domain" concept (Schmitz et al, 2017;Wirsing et al, 2021). Under this framework, prey with domains that extend beyond those of their predators should rely on avoidance to minimize encounters, whereas those whose domains fall within that of a predator are expected to experience more encounters and utilize defenses that reduce the likelihood of death given an encounter.…”

“…When they perceive predation risk, prey individuals commonly sacrifice food in exchange for the safety afforded by differential space use (e.g., refuging), apprehension, or group size (Lima and Dill, 1990;Preisser et al, 2005;Cresswell, 2008;Say-Sallaz et al, 2019). There is growing recognition, however, that such anti-predator investment can vary in nature and intensity as a function of context, or, in other words, properties of the prey experiencing the danger, the predator imposing the threat, and/or the setting of the interaction (Wirsing et al, 2021). For example, prey energetic state (i.e., body condition or hunger), is known to affect risk-taking behavior by mediating individual differences in the incentive to protect vs. seek assets (energy stores) linked to residual reproductive value (McNamara and Houston, 1986;Lima, 1988;Whitham and Mathis, 2000;Olsson et al, 2002;Heithaus et al, 2007).…”

Shade affects magnitude and tactics of juvenile Chinook salmon antipredator behavior in the migration corridor

“…For example, animals often perceive sheltered habitats to be less risky than exposed habitats, and consequently, in sheltered habitats prey allow predators to approach more closely before they flee (de Boer et al 2004). Habitat-dependent antipredator behavior has been heavily studied in resident prey and can scale up to affect populations and communities (Preisser et al 2005;Wirsing et al 2021). However, these antipredator decisions are much less studied in migrating animals, despite that migrants often experience high predation risk in migration corridors where they are concentrated and conspicuous (Furey et al 2018).…”

Chemical Cues from Entomopathogenic Nematodes Vary Across Three Species with Different Foraging Strategies, Triggering Different Behavioral Responses in Prey and Competitors

“…A major goal among ecologists is to better predict the outcomes of trophic interactions and their cascading consequences for community ecology and ecosystem function (Miller et al 2014;Culshaw-Maurer et al 2020;Descombes et al 2020). Growing evidence in the study of predator-prey interactions points to environmental (e.g., climate and habitat) and species (e.g., predator and prey) traits as playing key roles in disentangling this complexity (Rosenheim et al 2004;Luttbeg et al 2020;Wirsing et al 2021). Behavioral traits of both predators and prey are of increasing interest, particularly the role these traits play in non-consumptive effects.…”