Food-limitation in a generalist predator
Investigating food-limitation in generalist predators is difficult, because they can switch to alternative prey, when one of their staple prey becomes scarce. Apart from data on the dynamics of the predator population, a robust study requires: (i) a documentation of the predator's entire prey b...
Published in: | Proceedings of the Royal Society B: Biological Sciences |
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Online Access: | http://dx.doi.org/10.1098/rspb.2006.3507 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2006.3507 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2006.3507 |
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crroyalsociety:10.1098/rspb.2006.3507 2024-06-02T07:54:12+00:00 Food-limitation in a generalist predator Rutz, Christian Bijlsma, Rob G 2006 http://dx.doi.org/10.1098/rspb.2006.3507 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2006.3507 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2006.3507 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Proceedings of the Royal Society B: Biological Sciences volume 273, issue 1597, page 2069-2076 ISSN 0962-8452 1471-2954 journal-article 2006 crroyalsociety https://doi.org/10.1098/rspb.2006.3507 2024-05-07T14:16:49Z Investigating food-limitation in generalist predators is difficult, because they can switch to alternative prey, when one of their staple prey becomes scarce. Apart from data on the dynamics of the predator population, a robust study requires: (i) a documentation of the predator's entire prey base; and (ii) an experimental or natural situation, where profitable dietary shifts are impossible, because several preferred prey species decline simultaneously. Here, we provide a detailed description of how food-supply has limited a generalist avian top predator, the northern goshawk Accipiter gentilis . In our study area, populations of several principal goshawk prey species crashed simultaneously during 1975–2000, whereas other extrinsic factors remained essentially unchanged. The breeding and non-breeding segments of the local goshawk population declined markedly, associated with a significant increase in nest failures. Brood size of successful pairs remained unaffected by changes in prey availability. Breeding recruitment ceased at a time when potential replacement birds (‘floaters’) were still present, providing a rare empirical demonstration of an ‘acceptance threshold’ in raptor territory choice. To investigate how goshawk diet changed in response to varying food-supplies, we make novel use of an analytical tool from biodiversity research—‘ a bundance– b iomass– c omparison curves’ (ABC curves). With increasing levels of food-stress, the dominance of principal prey species in the diet decreased, and the number of small-bodied prey species increased, as did intra-guild predation. Our finding that breeder and non-breeder segments declined in concert is unexpected. Our results carry the management implication that, in food-limited raptor populations, externally induced breeder mortality can rapidly depress population size, as losses are no longer buffered when floaters reject breeding opportunities. Article in Journal/Newspaper Accipiter gentilis Northern Goshawk The Royal Society Proceedings of the Royal Society B: Biological Sciences 273 1597 2069 2076 |
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Open Polar |
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The Royal Society |
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crroyalsociety |
language |
English |
description |
Investigating food-limitation in generalist predators is difficult, because they can switch to alternative prey, when one of their staple prey becomes scarce. Apart from data on the dynamics of the predator population, a robust study requires: (i) a documentation of the predator's entire prey base; and (ii) an experimental or natural situation, where profitable dietary shifts are impossible, because several preferred prey species decline simultaneously. Here, we provide a detailed description of how food-supply has limited a generalist avian top predator, the northern goshawk Accipiter gentilis . In our study area, populations of several principal goshawk prey species crashed simultaneously during 1975–2000, whereas other extrinsic factors remained essentially unchanged. The breeding and non-breeding segments of the local goshawk population declined markedly, associated with a significant increase in nest failures. Brood size of successful pairs remained unaffected by changes in prey availability. Breeding recruitment ceased at a time when potential replacement birds (‘floaters’) were still present, providing a rare empirical demonstration of an ‘acceptance threshold’ in raptor territory choice. To investigate how goshawk diet changed in response to varying food-supplies, we make novel use of an analytical tool from biodiversity research—‘ a bundance– b iomass– c omparison curves’ (ABC curves). With increasing levels of food-stress, the dominance of principal prey species in the diet decreased, and the number of small-bodied prey species increased, as did intra-guild predation. Our finding that breeder and non-breeder segments declined in concert is unexpected. Our results carry the management implication that, in food-limited raptor populations, externally induced breeder mortality can rapidly depress population size, as losses are no longer buffered when floaters reject breeding opportunities. |
format |
Article in Journal/Newspaper |
author |
Rutz, Christian Bijlsma, Rob G |
spellingShingle |
Rutz, Christian Bijlsma, Rob G Food-limitation in a generalist predator |
author_facet |
Rutz, Christian Bijlsma, Rob G |
author_sort |
Rutz, Christian |
title |
Food-limitation in a generalist predator |
title_short |
Food-limitation in a generalist predator |
title_full |
Food-limitation in a generalist predator |
title_fullStr |
Food-limitation in a generalist predator |
title_full_unstemmed |
Food-limitation in a generalist predator |
title_sort |
food-limitation in a generalist predator |
publisher |
The Royal Society |
publishDate |
2006 |
url |
http://dx.doi.org/10.1098/rspb.2006.3507 https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2006.3507 https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2006.3507 |
genre |
Accipiter gentilis Northern Goshawk |
genre_facet |
Accipiter gentilis Northern Goshawk |
op_source |
Proceedings of the Royal Society B: Biological Sciences volume 273, issue 1597, page 2069-2076 ISSN 0962-8452 1471-2954 |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rspb.2006.3507 |
container_title |
Proceedings of the Royal Society B: Biological Sciences |
container_volume |
273 |
container_issue |
1597 |
container_start_page |
2069 |
op_container_end_page |
2076 |
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1800745397684011008 |