Abstract
Fear of predation produces large effects on prey population dynamics through indirect risk effects that can cause even greater impacts than direct predation mortality. As yet, there is no general theoretical framework for predicting when and how these population risk effects will arise in specific prey populations, meaning that there is often little consideration given to the key role predator risk effects can play in understanding conservation and wildlife management challenges. Here, we propose that population predator risk effects can be predicted through an extension of individual risk trade-off theory and show for the first time that this is the case in a wild vertebrate system. Specifically, we demonstrate that the timing (in specific months of the year), occurrence (at low food availability), cause (reduction in individual energy reserves), and type (starvation mortality) of a population-level predator risk effect can be successfully predicted from individual responses using a widely applicable theoretical framework (individual-based risk trade-off theory). Our results suggest that individual-based risk trade-off frameworks could allow a wide range of population-level predator risk effects to be predicted from existing ecological theory, which would enable risk effects to be more routinely integrated into consideration of population processes and in applied situations such as conservation.
Original language | English |
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Pages (from-to) | 2006-2015 |
Number of pages | 10 |
Journal | Ecology |
Volume | 95 |
Issue number | 7 |
DOIs | |
Publication status | Published - Jul 2014 |
Bibliographical note
Date of Acceptance: 17/12/2014This work formed part of the EU-funded BIOCET project (Bioaccumulation of persistent organic pollutants in small cetaceans in European waters: transport pathways and impact on reproduction, EVK3-2000-00027). We are grateful to our Project Officer, Cathy Eccles, for her support. The UK marine mammal strandings program, funded by DEFRA as part of its commitment to the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas, supported attendance at strandings and necropsies. We thank Tony Patterson and Robert Reid for their contributions to data collection in Scotland. R. MacLeod is supported by a Royal Society of Edinburgh Scottish Government Research Fellowship. C. D. MacLeod and R. MacLeod contributed equally to this study
and are regarded as joint first authors.
Keywords
- bottlenose dolphin
- Tursiops truncates
- harbor porpoise
- Phocoena phocoena
- indirect effects individual-based theory
- lethal porpoise dolphin interactions
- mass-dependent predation risk
- nonconsumptive effects
- nonlethal predator effects
- sandeel
- Ammodytes marinus
- Scotland
- starvation-predation risk trade-off
- mediated indirect interactions
- bottle-nosed dolphins
- harbor porpoises
- body-mass
- wintering birds
- violent interactions
- relative importance
- Parus-Major
- trade-off