Abstract
Currently, there is no general agreement about the extent to which predators impact prey population dynamics and it is often poorly predicted by predation rates and species abundances. This could, in part be caused by variation in the type of selective predation occurring. Notably, if predation is selective on categories of individuals that contribute little to future generations, it may moderate the impact of predation on prey population dynamics. However, despite its prevalence, selective predation has seldom been studied in this context. Using recoveries of ringed tawny owls (Strix aluco) predated by 'superpredators', northern goshawks (Accipiter gentilis) as they colonized the area, we investigated the extent to which predation was sex and age-selective. Predation of juvenile owls was disproportionately high. Amongst adults, predation was strongly biased towards females and predation risk appeared to increase with age. This implies age-selective predation may shape the decline in survival with age, observed in tawny owls. To determine whether selective predation can modulate the overall impact of predation, age-based population matrix models were used to simulate the impact of five different patterns of age-selective predation, including the pattern actually observed in the study site. The overall impact on owl population size varied by up to 50%, depending on the pattern of selective predation. The simulation of the observed pattern of predation had a relatively small impact on population size, close to the least harmful scenario, predation on juveniles only. The actual changes in owl population size and structure observed during goshawk colonization were also analysed. Owl population size and immigration were unrelated to goshawk abundance. However, goshawk abundance appeared to interact with owl food availability to have a delayed effect on recruitment into the population. This study provides strong evidence to suggest that predation of other predators is both age and sex-selective and that selective predation of individuals with a low reproductive value may mitigate the overall impact of predators on prey population dynamics. Consequently, our results highlight how accounting for the type of selective predation occurring is likely to improve future predictions of the overall impact of predation.
Original language | English |
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Pages (from-to) | 692-701 |
Number of pages | 10 |
Journal | Journal of Animal Ecology |
Volume | 84 |
Issue number | 3 |
Early online date | 3 Dec 2014 |
DOIs | |
Publication status | Published - May 2015 |
Bibliographical note
© 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.Acknowledgements:
Thanks to J. Reid, S. Redpath, A. Beckerman and an anonymous reviewer for their helpful comments on a previous version of the manuscript. This work was partly funded by a Natural Environment Research Council studentship NE/J500148/1 to SH and a grant NE/F021402/1 to XL and by Natural Research Limited. Forest Research funded all the fieldwork on goshawks, tawny owls and field voles during 1973–1996. We thank B. Little, P. Hotchin, D. Anderson and all field assistants for their help with data collection and Forest Enterprise, T. Dearnley and N. Geddes for allowing and facilitating work in Kielder Forest. In addition, we are grateful to English Nature and the BTO for kindly issuing licences annually visit goshawk nest sites.
Data accessibility:
All data associated with the study which have not already been given in the text are available from the Dryad Digital Repository: http://doi.org/10.5061/dryad.h1289 (Hoy et al. 2014).
Keywords
- Accipiter gentilis
- mesopredator
- northern goshawk
- population dynamics
- predatory interactions
- recruitment
- senescence
- Strix aluco
- superpredator
- tawny owl
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Dive into the research topics of 'Age and sex-selective predation moderate the overall impact of predators'. Together they form a unique fingerprint.Datasets
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Estimated age at death for owl ring recoveries, and recruitment of breeders into the owl population
Hoy, S. R. (Creator), Petty, S. J. (Creator), Millon, A. (Creator), Whitfield, D. P. (Creator), Marquiss, M. (Creator), Davidson, M. (Creator) & Lambin, X. (Creator), British Ecological Society, 30 Oct 2014
DOI: 10.5061/dryad.h1289, http://dx.doi.org/10.1111/1365-2656.12310
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Xavier Lambin
- Biological Sciences, Aberdeen Centre For Environmental Sustainability - Chair in Zoology
Person: Academic