Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019
Penguins are among the most important avian predators in the Southern Ocean, consuming large amounts of prey. Macaroni Penguins Eudyptes chrysolophus and Eastern Rockhopper Penguins E. filholi are listed as Vulnerable due to large-scale population declines across their distributions. The aim of my t...
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Online Access: | http://hdl.handle.net/11427/37072 https://open.uct.ac.za/bitstream/11427/37072/1/thesis_sci_2022_dakwa%20farisayi%20e.pdf |
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ftunivcapetownir:oai:localhost:11427/37072 2023-05-15T13:46:03+02:00 Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 Dakwa, Farisayi E Makhado, Azwianewi Ryan, Peter 2022_ application/pdf http://hdl.handle.net/11427/37072 https://open.uct.ac.za/bitstream/11427/37072/1/thesis_sci_2022_dakwa%20farisayi%20e.pdf eng eng Faculty of Science Department of Biological Sciences http://hdl.handle.net/11427/37072 https://open.uct.ac.za/bitstream/11427/37072/1/thesis_sci_2022_dakwa%20farisayi%20e.pdf Biological Sciences Master Thesis Masters MSc 2022 ftunivcapetownir 2023-03-03T00:14:39Z Penguins are among the most important avian predators in the Southern Ocean, consuming large amounts of prey. Macaroni Penguins Eudyptes chrysolophus and Eastern Rockhopper Penguins E. filholi are listed as Vulnerable due to large-scale population declines across their distributions. The aim of my thesis is to update trends in the breeding populations of Macaroni and Eastern Rockhopper Penguins at Marion Island from 1994–2019. The breeding population of Macaroni Penguins has decreased more or less consistently at an average rate of 1.9% per year since 1994, whereas Eastern Rockhopper Penguins showed a rapid initial decline of 13% per year from 1994–2001, then stabilised to fluctuate between 55 000 and 80 000 pairs. I assess the long-term trends in pre-breeding condition (arrival dates and mass on arrival for breeding) and breeding performance (breeding success and fledgling mass) of both Macaroni and Eastern Rockhopper Penguins. I also compare within and between these variables to explain trends in the breeding population of both penguins for the last two decades. There was inter-annual variation in pre-breeding variables (arrival dates and mass on arrival) and breeding variables (breeding success and fledging mass) in both penguins which could indicate variability in prey availability and climatic conditions across the breeding seasons from 1994–2019. Over the study period, Macaroni Penguins arrived to breed 3–5 weeks earlier than Eastern Rockhopper Penguins on Marion Island. There was no consistent trend in mass on arrival among male or female Macaroni Penguins but Eastern Rockhopper Penguin mass on arrival decreased from 1994 to 2007 and then had an increasing trend post 2007 for both sexes. Breeding success of Macaroni Penguins fluctuated annually with no obvious trend, whereas the breeding success of Eastern Rockhopper Penguins increased at all three study locations. This increase in body condition and breeding success could explain the stabilising population of Eastern Rockhopper Penguins at Marion Island. ... Master Thesis Antarc* Antarctic Eudyptes chrysolophus Marion Island Rockhopper penguin Southern Ocean University of Cape Town: OpenUCT Antarctic Southern Ocean |
institution |
Open Polar |
collection |
University of Cape Town: OpenUCT |
op_collection_id |
ftunivcapetownir |
language |
English |
topic |
Biological Sciences |
spellingShingle |
Biological Sciences Dakwa, Farisayi E Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 |
topic_facet |
Biological Sciences |
description |
Penguins are among the most important avian predators in the Southern Ocean, consuming large amounts of prey. Macaroni Penguins Eudyptes chrysolophus and Eastern Rockhopper Penguins E. filholi are listed as Vulnerable due to large-scale population declines across their distributions. The aim of my thesis is to update trends in the breeding populations of Macaroni and Eastern Rockhopper Penguins at Marion Island from 1994–2019. The breeding population of Macaroni Penguins has decreased more or less consistently at an average rate of 1.9% per year since 1994, whereas Eastern Rockhopper Penguins showed a rapid initial decline of 13% per year from 1994–2001, then stabilised to fluctuate between 55 000 and 80 000 pairs. I assess the long-term trends in pre-breeding condition (arrival dates and mass on arrival for breeding) and breeding performance (breeding success and fledgling mass) of both Macaroni and Eastern Rockhopper Penguins. I also compare within and between these variables to explain trends in the breeding population of both penguins for the last two decades. There was inter-annual variation in pre-breeding variables (arrival dates and mass on arrival) and breeding variables (breeding success and fledging mass) in both penguins which could indicate variability in prey availability and climatic conditions across the breeding seasons from 1994–2019. Over the study period, Macaroni Penguins arrived to breed 3–5 weeks earlier than Eastern Rockhopper Penguins on Marion Island. There was no consistent trend in mass on arrival among male or female Macaroni Penguins but Eastern Rockhopper Penguin mass on arrival decreased from 1994 to 2007 and then had an increasing trend post 2007 for both sexes. Breeding success of Macaroni Penguins fluctuated annually with no obvious trend, whereas the breeding success of Eastern Rockhopper Penguins increased at all three study locations. This increase in body condition and breeding success could explain the stabilising population of Eastern Rockhopper Penguins at Marion Island. ... |
author2 |
Makhado, Azwianewi Ryan, Peter |
format |
Master Thesis |
author |
Dakwa, Farisayi E |
author_facet |
Dakwa, Farisayi E |
author_sort |
Dakwa, Farisayi E |
title |
Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 |
title_short |
Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 |
title_full |
Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 |
title_fullStr |
Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 |
title_full_unstemmed |
Influence of ecosystem variability on the demography and reproductive performance of two Eudyptes penguins, Macaroni and Eastern Rockhopper Penguins, at sub-Antarctic Marion Island, 1994–2019 |
title_sort |
influence of ecosystem variability on the demography and reproductive performance of two eudyptes penguins, macaroni and eastern rockhopper penguins, at sub-antarctic marion island, 1994–2019 |
publisher |
Faculty of Science |
publishDate |
2022 |
url |
http://hdl.handle.net/11427/37072 https://open.uct.ac.za/bitstream/11427/37072/1/thesis_sci_2022_dakwa%20farisayi%20e.pdf |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Eudyptes chrysolophus Marion Island Rockhopper penguin Southern Ocean |
genre_facet |
Antarc* Antarctic Eudyptes chrysolophus Marion Island Rockhopper penguin Southern Ocean |
op_relation |
http://hdl.handle.net/11427/37072 https://open.uct.ac.za/bitstream/11427/37072/1/thesis_sci_2022_dakwa%20farisayi%20e.pdf |
_version_ |
1766235410161205248 |