Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders
Abstract Ego net analysis is a well‐known practice in social sciences, where an ego net (EN) consists of a focal node, the ego, and its links to other nodes, called alters, and alter–alter links may also be included. An EN describes how a focal node is embedded in its interaction context. Here, I in...
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ftdoajarticles:oai:doaj.org/article:9dbb5960de764dc8913d07bbbda897d8 2023-05-15T13:56:15+02:00 Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders Jens M. Olesen 2022-05-01T00:00:00Z https://doi.org/10.1002/ece3.8916 https://doaj.org/article/9dbb5960de764dc8913d07bbbda897d8 EN eng Wiley https://doi.org/10.1002/ece3.8916 https://doaj.org/toc/2045-7758 2045-7758 doi:10.1002/ece3.8916 https://doaj.org/article/9dbb5960de764dc8913d07bbbda897d8 Ecology and Evolution, Vol 12, Iss 5, Pp n/a-n/a (2022) Ecology QH540-549.5 article 2022 ftdoajarticles https://doi.org/10.1002/ece3.8916 2022-12-31T01:52:56Z Abstract Ego net analysis is a well‐known practice in social sciences, where an ego net (EN) consists of a focal node, the ego, and its links to other nodes, called alters, and alter–alter links may also be included. An EN describes how a focal node is embedded in its interaction context. Here, I introduce EN analysis to ecology in a study of the trophic network of a sub‐Antarctic land bird, Lesser Sheathbill (Chionis minor). Data originate from the sheathbill population on Marion Island in the Southern Ocean. The bird is ego and its enemies and food are alters. The EN is organized along three dimensions: habitat, interaction type, and time (from before human arrival in 1803 and until a future year 2100). Ten EN descriptors are defined, estimated, and used to track the 300 years of change in sheathbill EN structure. Since 1803, the EN has passed two major, but reversible shifts—seal exploitation in the 19th century and presence of cats from 1949 to 1991. These shifts can be read as structural changes in the sheathbill EN. In the future, a third, perhaps irreversible change is predicted, driven by climate change and a surprising, recent shift to seabird predation by House Mouse, the most detrimental of all extant invaders on Marion. In a warmer and drier future, the mouse will proliferate, and if this forces seabirds to abandon the island, their accumulation of detritus runs dry, starving a rich invertebrate detritivore fauna, which also is a key food source to sheathbills. These detritivores together with plants have also constituted the main food sources of mice. The EN descriptors quantify that story. In the future, these events may lead to a collapse of the island ecosystem, including extinction of the sheathbill—unless plans for mouse eradication are implemented. Article in Journal/Newspaper Antarc* Antarctic Marion Island Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean Chionis ENVELOPE(-60.633,-60.633,-63.883,-63.883) Ecology and Evolution 12 5 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 |
spellingShingle |
Ecology QH540-549.5 Jens M. Olesen Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
topic_facet |
Ecology QH540-549.5 |
description |
Abstract Ego net analysis is a well‐known practice in social sciences, where an ego net (EN) consists of a focal node, the ego, and its links to other nodes, called alters, and alter–alter links may also be included. An EN describes how a focal node is embedded in its interaction context. Here, I introduce EN analysis to ecology in a study of the trophic network of a sub‐Antarctic land bird, Lesser Sheathbill (Chionis minor). Data originate from the sheathbill population on Marion Island in the Southern Ocean. The bird is ego and its enemies and food are alters. The EN is organized along three dimensions: habitat, interaction type, and time (from before human arrival in 1803 and until a future year 2100). Ten EN descriptors are defined, estimated, and used to track the 300 years of change in sheathbill EN structure. Since 1803, the EN has passed two major, but reversible shifts—seal exploitation in the 19th century and presence of cats from 1949 to 1991. These shifts can be read as structural changes in the sheathbill EN. In the future, a third, perhaps irreversible change is predicted, driven by climate change and a surprising, recent shift to seabird predation by House Mouse, the most detrimental of all extant invaders on Marion. In a warmer and drier future, the mouse will proliferate, and if this forces seabirds to abandon the island, their accumulation of detritus runs dry, starving a rich invertebrate detritivore fauna, which also is a key food source to sheathbills. These detritivores together with plants have also constituted the main food sources of mice. The EN descriptors quantify that story. In the future, these events may lead to a collapse of the island ecosystem, including extinction of the sheathbill—unless plans for mouse eradication are implemented. |
format |
Article in Journal/Newspaper |
author |
Jens M. Olesen |
author_facet |
Jens M. Olesen |
author_sort |
Jens M. Olesen |
title |
Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
title_short |
Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
title_full |
Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
title_fullStr |
Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
title_full_unstemmed |
Ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
title_sort |
ego network analysis of the trophic structure of an island land bird through 300 years of climate change and invaders |
publisher |
Wiley |
publishDate |
2022 |
url |
https://doi.org/10.1002/ece3.8916 https://doaj.org/article/9dbb5960de764dc8913d07bbbda897d8 |
long_lat |
ENVELOPE(-60.633,-60.633,-63.883,-63.883) |
geographic |
Antarctic Southern Ocean Chionis |
geographic_facet |
Antarctic Southern Ocean Chionis |
genre |
Antarc* Antarctic Marion Island Southern Ocean |
genre_facet |
Antarc* Antarctic Marion Island Southern Ocean |
op_source |
Ecology and Evolution, Vol 12, Iss 5, Pp n/a-n/a (2022) |
op_relation |
https://doi.org/10.1002/ece3.8916 https://doaj.org/toc/2045-7758 2045-7758 doi:10.1002/ece3.8916 https://doaj.org/article/9dbb5960de764dc8913d07bbbda897d8 |
op_doi |
https://doi.org/10.1002/ece3.8916 |
container_title |
Ecology and Evolution |
container_volume |
12 |
container_issue |
5 |
_version_ |
1766263619535765504 |