Evidence for an Allee effect in a declining fur seal population
Allee effects play an important role in the dynamics of many populations and can increase the risk of local extinction. However, some authors have questioned the weight of evidence for Allee effects in wild populations. We therefore exploited a natural experiment provided by two adjacent breeding co...
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ftzenodo:oai:zenodo.org:4553841 2024-09-09T19:07:15+00:00 Evidence for an Allee effect in a declining fur seal population Nagel, Rebecca Stainfield, Claire Fox-Clarke, Cameron Toscani, Camille Forcada, Jaume Hoffman, Joseph 2021-03-04 https://doi.org/10.5281/zenodo.4553841 unknown Zenodo https://doi.org/10.32942/osf.io/acu5h https://doi.org/10.5061/dryad.zcrjdfnb0 https://zenodo.org/communities/dryad https://doi.org/10.5281/zenodo.4553840 https://doi.org/10.5281/zenodo.4553841 oai:zenodo.org:4553841 info:eu-repo/semantics/openAccess MIT License https://opensource.org/licenses/MIT info:eu-repo/semantics/other 2021 ftzenodo https://doi.org/10.5281/zenodo.455384110.32942/osf.io/acu5h10.5061/dryad.zcrjdfnb010.5281/zenodo.4553840 2024-07-26T11:40:05Z Allee effects play an important role in the dynamics of many populations and can increase the risk of local extinction. However, some authors have questioned the weight of evidence for Allee effects in wild populations. We therefore exploited a natural experiment provided by two adjacent breeding colonies of contrasting density to investigate the potential for Allee effects in an Antarctic fur seal ( Arctocephalus gazella ) population that is declining in response to climate-change induced reductions in food availability. Biometric time-series data were collected from 25 pups per colony during two consecutive breeding seasons, the first of which was amongst the worst on record in terms of breeding female numbers, pup birth weights and foraging trip durations. In previous decades when population densities were higher, pup mortality was consistently negatively density-dependent, with rates of trauma and starvation scaling positively with density. However, we found the opposite, with higher pup mortality at low density and the majority of deaths attributable to predation. In parallel, body condition was also depressed at low density, particularly in the poor-quality season. Our findings shed light on Allee effects in wild populations and highlight a potential emerging role of predators in the ongoing decline of a pinniped species. Funding provided by: Deutsche Forschungsgemeinschaft Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100001659 Award Number: 316099922 Funding provided by: Deutsche Forschungsgemeinschaft Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100001659 Award Number: 396774617 Other/Unknown Material Antarc* Antarctic Antarctic Fur Seal Arctocephalus gazella Zenodo Antarctic |
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Allee effects play an important role in the dynamics of many populations and can increase the risk of local extinction. However, some authors have questioned the weight of evidence for Allee effects in wild populations. We therefore exploited a natural experiment provided by two adjacent breeding colonies of contrasting density to investigate the potential for Allee effects in an Antarctic fur seal ( Arctocephalus gazella ) population that is declining in response to climate-change induced reductions in food availability. Biometric time-series data were collected from 25 pups per colony during two consecutive breeding seasons, the first of which was amongst the worst on record in terms of breeding female numbers, pup birth weights and foraging trip durations. In previous decades when population densities were higher, pup mortality was consistently negatively density-dependent, with rates of trauma and starvation scaling positively with density. However, we found the opposite, with higher pup mortality at low density and the majority of deaths attributable to predation. In parallel, body condition was also depressed at low density, particularly in the poor-quality season. Our findings shed light on Allee effects in wild populations and highlight a potential emerging role of predators in the ongoing decline of a pinniped species. Funding provided by: Deutsche Forschungsgemeinschaft Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100001659 Award Number: 316099922 Funding provided by: Deutsche Forschungsgemeinschaft Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100001659 Award Number: 396774617 |
format |
Other/Unknown Material |
author |
Nagel, Rebecca Stainfield, Claire Fox-Clarke, Cameron Toscani, Camille Forcada, Jaume Hoffman, Joseph |
spellingShingle |
Nagel, Rebecca Stainfield, Claire Fox-Clarke, Cameron Toscani, Camille Forcada, Jaume Hoffman, Joseph Evidence for an Allee effect in a declining fur seal population |
author_facet |
Nagel, Rebecca Stainfield, Claire Fox-Clarke, Cameron Toscani, Camille Forcada, Jaume Hoffman, Joseph |
author_sort |
Nagel, Rebecca |
title |
Evidence for an Allee effect in a declining fur seal population |
title_short |
Evidence for an Allee effect in a declining fur seal population |
title_full |
Evidence for an Allee effect in a declining fur seal population |
title_fullStr |
Evidence for an Allee effect in a declining fur seal population |
title_full_unstemmed |
Evidence for an Allee effect in a declining fur seal population |
title_sort |
evidence for an allee effect in a declining fur seal population |
publisher |
Zenodo |
publishDate |
2021 |
url |
https://doi.org/10.5281/zenodo.4553841 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Antarctic Fur Seal Arctocephalus gazella |
genre_facet |
Antarc* Antarctic Antarctic Fur Seal Arctocephalus gazella |
op_relation |
https://doi.org/10.32942/osf.io/acu5h https://doi.org/10.5061/dryad.zcrjdfnb0 https://zenodo.org/communities/dryad https://doi.org/10.5281/zenodo.4553840 https://doi.org/10.5281/zenodo.4553841 oai:zenodo.org:4553841 |
op_rights |
info:eu-repo/semantics/openAccess MIT License https://opensource.org/licenses/MIT |
op_doi |
https://doi.org/10.5281/zenodo.455384110.32942/osf.io/acu5h10.5061/dryad.zcrjdfnb010.5281/zenodo.4553840 |
_version_ |
1809821318361645056 |