Ecological drivers of change at South Georgia: the krill surplus, or climate variability
Macaroni penguins Eudyptes chrysolophus are thought to be one of the most important mesopredators in the Southern Ocean having a greater impact on prey availability and abundance than any other seabird species. Their population centre has long been held to be South Georgia where populations were tho...
Published in: | Ecography |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
Wiley
2012
|
Subjects: | |
Online Access: | http://nora.nerc.ac.uk/id/eprint/17803/ |
id |
ftnerc:oai:nora.nerc.ac.uk:17803 |
---|---|
record_format |
openpolar |
spelling |
ftnerc:oai:nora.nerc.ac.uk:17803 2023-05-15T13:45:12+02:00 Ecological drivers of change at South Georgia: the krill surplus, or climate variability Trathan, Phil Ratcliffe, Norman Masden, E.A. 2012 http://nora.nerc.ac.uk/id/eprint/17803/ unknown Wiley Trathan, Phil orcid:0000-0001-6673-9930 Ratcliffe, Norman orcid:0000-0002-3375-2431 Masden, E.A. 2012 Ecological drivers of change at South Georgia: the krill surplus, or climate variability. Ecography, 35 (11). 983-993. https://doi.org/10.1111/j.1600-0587.2012.07330.x <https://doi.org/10.1111/j.1600-0587.2012.07330.x> Publication - Article PeerReviewed 2012 ftnerc https://doi.org/10.1111/j.1600-0587.2012.07330.x 2023-02-04T19:31:21Z Macaroni penguins Eudyptes chrysolophus are thought to be one of the most important mesopredators in the Southern Ocean having a greater impact on prey availability and abundance than any other seabird species. Their population centre has long been held to be South Georgia where populations were thought to comprise many million animals. Here we report the results of a recent census of the macaroni population at South Georgia undertaken using aerial survey methods. We report dramatic declines in numbers (∼1.0 million breeding pairs) compared to numbers observed in the late 1970s (∼5.4 million pairs), but show that these reductions have occurred principally at sites where numbers had previously been very large. During the breeding season, the main foraging grounds of birds from these sites overlap with the foraging grounds of Antarctic fur seals Arctocephalus gazella, a major competitor for their principal prey, Antarctic krill Euphausia superba. We suggest that the redistribution of the macaroni penguin population at South Georgia reflects the recent recovery of fur seal populations and thus the ongoing consequences of human intervention at South Georgia, a process which started more than 2 centuries previously. The implied resource competition and the observed population changes may also be exacerbated by recent reductions in Antarctic krill abundance which have been linked with reductions in seasonal sea ice following recent, rapid, regional warming in the Antarctic; however, the recovery of fur seal populations, and the ongoing recovery of krill-eating whale populations argues that tropho-dynamic interactions may be sufficient to explain the observed changes Article in Journal/Newspaper Antarc* Antarctic Antarctic Fur Seals Antarctic Krill Arctocephalus gazella Eudyptes chrysolophus Euphausia superba Macaroni penguin Sea ice Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean The Antarctic Ecography 35 11 983 993 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
Macaroni penguins Eudyptes chrysolophus are thought to be one of the most important mesopredators in the Southern Ocean having a greater impact on prey availability and abundance than any other seabird species. Their population centre has long been held to be South Georgia where populations were thought to comprise many million animals. Here we report the results of a recent census of the macaroni population at South Georgia undertaken using aerial survey methods. We report dramatic declines in numbers (∼1.0 million breeding pairs) compared to numbers observed in the late 1970s (∼5.4 million pairs), but show that these reductions have occurred principally at sites where numbers had previously been very large. During the breeding season, the main foraging grounds of birds from these sites overlap with the foraging grounds of Antarctic fur seals Arctocephalus gazella, a major competitor for their principal prey, Antarctic krill Euphausia superba. We suggest that the redistribution of the macaroni penguin population at South Georgia reflects the recent recovery of fur seal populations and thus the ongoing consequences of human intervention at South Georgia, a process which started more than 2 centuries previously. The implied resource competition and the observed population changes may also be exacerbated by recent reductions in Antarctic krill abundance which have been linked with reductions in seasonal sea ice following recent, rapid, regional warming in the Antarctic; however, the recovery of fur seal populations, and the ongoing recovery of krill-eating whale populations argues that tropho-dynamic interactions may be sufficient to explain the observed changes |
format |
Article in Journal/Newspaper |
author |
Trathan, Phil Ratcliffe, Norman Masden, E.A. |
spellingShingle |
Trathan, Phil Ratcliffe, Norman Masden, E.A. Ecological drivers of change at South Georgia: the krill surplus, or climate variability |
author_facet |
Trathan, Phil Ratcliffe, Norman Masden, E.A. |
author_sort |
Trathan, Phil |
title |
Ecological drivers of change at South Georgia: the krill surplus, or climate variability |
title_short |
Ecological drivers of change at South Georgia: the krill surplus, or climate variability |
title_full |
Ecological drivers of change at South Georgia: the krill surplus, or climate variability |
title_fullStr |
Ecological drivers of change at South Georgia: the krill surplus, or climate variability |
title_full_unstemmed |
Ecological drivers of change at South Georgia: the krill surplus, or climate variability |
title_sort |
ecological drivers of change at south georgia: the krill surplus, or climate variability |
publisher |
Wiley |
publishDate |
2012 |
url |
http://nora.nerc.ac.uk/id/eprint/17803/ |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctic Fur Seals Antarctic Krill Arctocephalus gazella Eudyptes chrysolophus Euphausia superba Macaroni penguin Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Fur Seals Antarctic Krill Arctocephalus gazella Eudyptes chrysolophus Euphausia superba Macaroni penguin Sea ice Southern Ocean |
op_relation |
Trathan, Phil orcid:0000-0001-6673-9930 Ratcliffe, Norman orcid:0000-0002-3375-2431 Masden, E.A. 2012 Ecological drivers of change at South Georgia: the krill surplus, or climate variability. Ecography, 35 (11). 983-993. https://doi.org/10.1111/j.1600-0587.2012.07330.x <https://doi.org/10.1111/j.1600-0587.2012.07330.x> |
op_doi |
https://doi.org/10.1111/j.1600-0587.2012.07330.x |
container_title |
Ecography |
container_volume |
35 |
container_issue |
11 |
container_start_page |
983 |
op_container_end_page |
993 |
_version_ |
1766216451165782016 |