Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change
Marine communities represent biological networks, where physical and chemical changes in the marine environment can influence the physiology and behaviour of marine organisms. Stochastic marine conditions can alter key biological interactions and thus, influence the mechanisms that underpin populati...
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2017
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ftrhodesunivcory:vital:29452 2023-05-15T15:44:41+02:00 Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change Ryklief, Rabiah 2017 105 leaves pdf http://hdl.handle.net/10948/21167 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:29452 English eng Nelson Mandela Metropolitan University Faculty of Science http://hdl.handle.net/10948/21167 vital:29452 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:29452 Nelson Mandela Metropolitan University Endemic birds -- South Africa Marine pollution -- South Africa Thesis Doctoral PhD 2017 ftrhodesunivcory 2022-12-26T13:21:24Z Marine communities represent biological networks, where physical and chemical changes in the marine environment can influence the physiology and behaviour of marine organisms. Stochastic marine conditions can alter key biological interactions and thus, influence the mechanisms that underpin population demography and phenotypic plasticity. Marine top predators, such as seabirds, are often controlled by bottom-up processes and their ability to cope with variable ocean conditions lies in their physiological and behavioural response to such perturbations. Seabirds are central-place foragers during the breeding season making them particularly vulnerable to environmental fluctuations as they face constrains associated with reproductive effort in addition to self-maintenance. The Cape gannet Morus capensis is a medium-sized pelagic seabird that is endemic to southern Africa. The Cape gannet has experienced considerable change in population distribution and abundance over the past 50 years. These changes have been linked to a combination of fishing pressure and climate-mediated regime shifts of their preferred prey, i.e. sardine Sardinops sagax and anchovy ngraulis encrasicolus. Historically, Malgas Island was the largest Cape gannet colony in South Africa. However, it is now in a state of population decline, despite its occurrence within one of the most productive upwelling systems in the world, the Benguela Current. At present, Bird Island is the largest Cape gannet colony and has recently stabilised, despite regular immigration of gannets from the west coast. Furthermore, Bird Island lies within the Agulhas bioregion and is subject to low levels of productivity from the nutrient-poor Agulhas current. Malgas and Bird islands are the two most populous of the six extant Cape gannet colonies. Birds at these colonies provided a natural experiment due to the contrasting population trajectories and environmental conditions at their colonies. The foraging ecology and behaviour of Cape gannets were studied during the breeding ... Doctoral or Postdoctoral Thesis Bird Island Rhodes University Cory: Repository Bird Island ENVELOPE(-38.060,-38.060,-54.004,-54.004) |
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Rhodes University Cory: Repository |
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language |
English |
topic |
Endemic birds -- South Africa Marine pollution -- South Africa |
spellingShingle |
Endemic birds -- South Africa Marine pollution -- South Africa Ryklief, Rabiah Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
topic_facet |
Endemic birds -- South Africa Marine pollution -- South Africa |
description |
Marine communities represent biological networks, where physical and chemical changes in the marine environment can influence the physiology and behaviour of marine organisms. Stochastic marine conditions can alter key biological interactions and thus, influence the mechanisms that underpin population demography and phenotypic plasticity. Marine top predators, such as seabirds, are often controlled by bottom-up processes and their ability to cope with variable ocean conditions lies in their physiological and behavioural response to such perturbations. Seabirds are central-place foragers during the breeding season making them particularly vulnerable to environmental fluctuations as they face constrains associated with reproductive effort in addition to self-maintenance. The Cape gannet Morus capensis is a medium-sized pelagic seabird that is endemic to southern Africa. The Cape gannet has experienced considerable change in population distribution and abundance over the past 50 years. These changes have been linked to a combination of fishing pressure and climate-mediated regime shifts of their preferred prey, i.e. sardine Sardinops sagax and anchovy ngraulis encrasicolus. Historically, Malgas Island was the largest Cape gannet colony in South Africa. However, it is now in a state of population decline, despite its occurrence within one of the most productive upwelling systems in the world, the Benguela Current. At present, Bird Island is the largest Cape gannet colony and has recently stabilised, despite regular immigration of gannets from the west coast. Furthermore, Bird Island lies within the Agulhas bioregion and is subject to low levels of productivity from the nutrient-poor Agulhas current. Malgas and Bird islands are the two most populous of the six extant Cape gannet colonies. Birds at these colonies provided a natural experiment due to the contrasting population trajectories and environmental conditions at their colonies. The foraging ecology and behaviour of Cape gannets were studied during the breeding ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Ryklief, Rabiah |
author_facet |
Ryklief, Rabiah |
author_sort |
Ryklief, Rabiah |
title |
Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
title_short |
Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
title_full |
Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
title_fullStr |
Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
title_full_unstemmed |
Cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
title_sort |
cape gannets in contrasting environments: ehaviour, demographics and indicators of environmental change |
publisher |
Nelson Mandela Metropolitan University |
publishDate |
2017 |
url |
http://hdl.handle.net/10948/21167 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:29452 |
long_lat |
ENVELOPE(-38.060,-38.060,-54.004,-54.004) |
geographic |
Bird Island |
geographic_facet |
Bird Island |
genre |
Bird Island |
genre_facet |
Bird Island |
op_relation |
http://hdl.handle.net/10948/21167 vital:29452 https://corycommons.ru.ac.za/vital/access/manager/Repository/vital:29452 |
op_rights |
Nelson Mandela Metropolitan University |
_version_ |
1766379065426575360 |