Human impacts, energy availability and invasion across Southern Ocean Islands
Aim Ongoing biological invasions will enhance the impacts of humans on biodiversity. Nonetheless, the effects of exotic species on diversity are idiosyncratic. Increases in diversity might be a consequence of similar responses by species to available energy, or because of positive relationships betw...
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ftunstellenbosch:oai:scholar.sun.ac.za:10019.1/119998 2023-05-15T16:33:57+02:00 Human impacts, energy availability and invasion across Southern Ocean Islands Chown, SL Hull, B Gaston, KJ 2007-04-13T14:26:15Z 219013 bytes application/pdf http://hdl.handle.net/10019.1/119998 en eng BLACKWELL PUBLISHING 1466-822X http://hdl.handle.net/10019.1/119998 biological invasions disturbance diversity human history insects introduced species propagule pressure vascular plants Journal Articles 2007 ftunstellenbosch 2021-08-31T00:08:54Z Aim Ongoing biological invasions will enhance the impacts of humans on biodiversity. Nonetheless, the effects of exotic species on diversity are idiosyncratic. Increases in diversity might be a consequence of similar responses by species to available energy, or because of positive relationships between human density, energy and propagule pressure. Here we use data from the Southern Ocean island plants and insects to investigate these issues. Location The Southern Ocean Islands ranging from Tristan da Cunha to Heard Island and South Georgia. Methods Generalized linear models are used to explore the relationships between indigenous and exotic species richness for plants and insects on two different islands. Similar models are used to examine interactions between indigenous and exotic species richness, energy availability and propagule pressure at the regional scale. Results Positive relationships were found between indigenous and exotic species richness at local scales, although for plants, the relationship was partially triangular. Across the Southern Ocean Islands, there was strong positive covariation between indigenous and exotic plant species richness and insect species richness, even taking spatial autocorrelation into account. Both exotic and indigenous plant and insect species richness covaried with energy availability, as did human visitor frequency. When two islands with almost identical numbers of human visits were contrasted, it was clear that energy availability, or perhaps differences in climate-matching, were responsible for differences in the extent of invasion. Conclusion In plants and insects, there are positive relationships between indigenous and exotic diversity at local and regional scales across the Southern Ocean islands. These relationships are apparently a consequence of similar responses by both groups and by human occupants to available energy. When visitor frequency is held constant, energy availability is the major correlate of exotic species richness, though the exact mechanistic cause of this relationship requires clarification. Ctr Invas Biol Article in Journal/Newspaper Heard Island Southern Ocean Ocean Island Stellenbosch University: SUNScholar Research Repository Southern Ocean Heard Island Tristan ENVELOPE(140.900,140.900,-66.735,-66.735) |
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Stellenbosch University: SUNScholar Research Repository |
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ftunstellenbosch |
language |
English |
topic |
biological invasions disturbance diversity human history insects introduced species propagule pressure vascular plants |
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biological invasions disturbance diversity human history insects introduced species propagule pressure vascular plants Chown, SL Hull, B Gaston, KJ Human impacts, energy availability and invasion across Southern Ocean Islands |
topic_facet |
biological invasions disturbance diversity human history insects introduced species propagule pressure vascular plants |
description |
Aim Ongoing biological invasions will enhance the impacts of humans on biodiversity. Nonetheless, the effects of exotic species on diversity are idiosyncratic. Increases in diversity might be a consequence of similar responses by species to available energy, or because of positive relationships between human density, energy and propagule pressure. Here we use data from the Southern Ocean island plants and insects to investigate these issues. Location The Southern Ocean Islands ranging from Tristan da Cunha to Heard Island and South Georgia. Methods Generalized linear models are used to explore the relationships between indigenous and exotic species richness for plants and insects on two different islands. Similar models are used to examine interactions between indigenous and exotic species richness, energy availability and propagule pressure at the regional scale. Results Positive relationships were found between indigenous and exotic species richness at local scales, although for plants, the relationship was partially triangular. Across the Southern Ocean Islands, there was strong positive covariation between indigenous and exotic plant species richness and insect species richness, even taking spatial autocorrelation into account. Both exotic and indigenous plant and insect species richness covaried with energy availability, as did human visitor frequency. When two islands with almost identical numbers of human visits were contrasted, it was clear that energy availability, or perhaps differences in climate-matching, were responsible for differences in the extent of invasion. Conclusion In plants and insects, there are positive relationships between indigenous and exotic diversity at local and regional scales across the Southern Ocean islands. These relationships are apparently a consequence of similar responses by both groups and by human occupants to available energy. When visitor frequency is held constant, energy availability is the major correlate of exotic species richness, though the exact mechanistic cause of this relationship requires clarification. Ctr Invas Biol |
format |
Article in Journal/Newspaper |
author |
Chown, SL Hull, B Gaston, KJ |
author_facet |
Chown, SL Hull, B Gaston, KJ |
author_sort |
Chown, SL |
title |
Human impacts, energy availability and invasion across Southern Ocean Islands |
title_short |
Human impacts, energy availability and invasion across Southern Ocean Islands |
title_full |
Human impacts, energy availability and invasion across Southern Ocean Islands |
title_fullStr |
Human impacts, energy availability and invasion across Southern Ocean Islands |
title_full_unstemmed |
Human impacts, energy availability and invasion across Southern Ocean Islands |
title_sort |
human impacts, energy availability and invasion across southern ocean islands |
publisher |
BLACKWELL PUBLISHING |
publishDate |
2007 |
url |
http://hdl.handle.net/10019.1/119998 |
long_lat |
ENVELOPE(140.900,140.900,-66.735,-66.735) |
geographic |
Southern Ocean Heard Island Tristan |
geographic_facet |
Southern Ocean Heard Island Tristan |
genre |
Heard Island Southern Ocean Ocean Island |
genre_facet |
Heard Island Southern Ocean Ocean Island |
op_relation |
1466-822X http://hdl.handle.net/10019.1/119998 |
_version_ |
1766023689882566656 |