Hunting-mediated predator facilitation and superadditive mortality in a European ungulate.

Benedikt Gehr,Mirjam Pewsner,Kristina Vogt,Eric Vimercati,Andreas Ryser,Elizabeth J Hofer,Lukas F Keller

doi:10.1002/ece3.3642

Benedikt Gehr, Mirjam Pewsner + Show 5 more

Open Access

https://doi.org/10.1002/ece3.3642

Copy DOI

Abstract

Predator‐prey theory predicts that in the presence of multiple types of predators using a common prey, predator facilitation may result as a consequence of contrasting prey defense mechanisms, where reducing the risk from one predator increases the risk from the other. While predator facilitation is well established in natural predator‐prey systems, little attention has been paid to situations where human hunters compete with natural predators for the same prey. Here, we investigate hunting‐mediated predator facilitation in a hunter‐predator‐prey system. We found that hunter avoidance by roe deer (Capreolus capreolus) exposed them to increase predation risk by Eurasian lynx (Lynx lynx). Lynx responded by increasing their activity and predation on deer, providing evidence that superadditive hunting mortality may be occurring through predator facilitation. Our results reveal a new pathway through which human hunters, in their role as top predators, may affect species interactions at lower trophic levels and thus drive ecosystem processes.

Highlights

Predation risk is one of the key factors shaping animal space use patterns as prey species often have to trade off between finding enough food and being eaten (Lima & Dill, 1990; McNamara & Houston, 1987)
We found that roe deer avoided areas of high hunting risk during the hunting season at the expense of higher exposure to lynx predation risk
In turn, increased their activity in the forest between dawn and dusk and we found evidence of increased predation on deer during the hunting season. These results indicate that human hunting can induce predator facilitation through behavioral changes in both the prey and their natural predator, and we provide evidence that this predator facilitation resulted in superadditive mortality

Summary

Introduction

Predation risk is one of the key factors shaping animal space use patterns as prey species often have to trade off between finding enough food and being eaten (Lima & Dill, 1990; McNamara & Houston, 1987). Many prey species are eaten by more than one type of predator, resulting in a combination of threats that form a risk landscape through which animals have to move in order to acquire resources and reproduce (Sih, Englund, & Wooster, 1998). Prey defense mechanisms depend on the predator-s pecific hunting modes and the environmental context (Schmitz, 2008; Sih et al, 1998). Predator- specific prey defenses can lead to situations where avoiding one predator may increase the risk of being killed by another, a phenomenon known as predator facilitation (Charnov, Orians, & Hyatt, 1976). There are examples of predator facilitation from various systems in different taxonomic groups (e.g., Cresswell & Quinn, 2013; Fraser, Gilliam, Akkara, Albanese, & Snider, 2004; Kotler, Blaustein, & Brown, 1992), we do not understand how human hunters as top predators affect the susceptibility of their prey species to natural predators

Objectives

Findings

Discussion

Conclusion