Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem
Arctic regions are expected to experience an increase in both temperature and precipitation over the coming decades, which is likely to impact vegetation dynamics and greenhouse gas exchange. To test this response, an experiment was installed at the Cape Bounty Arctic Watershed Observatory, on Melvi...
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ftqueensuniv:oai:qspace.library.queensu.ca:1974/15283 2023-05-15T14:56:24+02:00 Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem Arruda, Sean Scott, Neal Geography and Planning 2016-12-13T21:57:28Z http://hdl.handle.net/1974/15283 eng eng Canadian theses http://hdl.handle.net/1974/15283 Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada ProQuest PhD and Master's Theses International Dissemination Agreement Intellectual Property Guidelines at Queen's University Copying and Preserving Your Thesis This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. Arctic vegetation phenology senescence carbon dioxide Cape Bounty thesis 2016 ftqueensuniv 2020-12-29T09:09:03Z Arctic regions are expected to experience an increase in both temperature and precipitation over the coming decades, which is likely to impact vegetation dynamics and greenhouse gas exchange. To test this response, an experiment was installed at the Cape Bounty Arctic Watershed Observatory, on Melville Island, NU, in 2008 as part of the International Tundra Experiment (ITEX). Snow fences and open top chambers (OTCs) were used to manipulate snow depth and air temperature, respectively. Unlike most ITEX sites to date, enhanced temperature and snowfall were combined here in a factorial design with eight replicates. As an added control, four plots were established well outside the enhanced snow area. Senescence date was recorded at the end of the season, and at the peak of the growing season a vegetation survey was conducted within each plot in order to determine the total percent cover of each plot, as well as the percent cover of individual species. Carbon dioxide (CO2) exchange was also measured within each plot throughout the growing season. The date of senescence occurred significantly earlier in plots which had not been manipulated in any way, compared to all other treatments for all species. Salix arctica showed the greatest increase in cover over time at the species level. Lichen cover increased significantly in the deepened snow plots, and in general there were significant increases in percent cover in some functional groups over time. During June and into July the net CO2 flux was to the atmosphere. It was not until July 27 that these ecosystems became net carbon sinks. However, warming alone resulted in the ecosystem acting as a significant net carbon sink for the entire growing season. Plots exposed to warming alone were estimated to have removed approximately 19.94 g C m-2 from the atmosphere, whereas all other treatments were very similar to one another and estimated to have added approximately 3.12 g C m-2 to the atmosphere. Active layer depth and soil temperatures suggest that plots within the ambient snow zone may be receiving some additional snow due to their proximity to the fences. CO2 fluxes measured within the outer control plots suggest that the effect of warming alone could lead to this ecosystem being an even stronger net C sink under truly ambient snow conditions. M.Sc. Thesis Arctic Tundra Melville Island Queen's University, Ontario: QSpace Arctic Cape Bounty ENVELOPE(-109.542,-109.542,74.863,74.863) |
institution |
Open Polar |
collection |
Queen's University, Ontario: QSpace |
op_collection_id |
ftqueensuniv |
language |
English |
topic |
Arctic vegetation phenology senescence carbon dioxide Cape Bounty |
spellingShingle |
Arctic vegetation phenology senescence carbon dioxide Cape Bounty Arruda, Sean Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem |
topic_facet |
Arctic vegetation phenology senescence carbon dioxide Cape Bounty |
description |
Arctic regions are expected to experience an increase in both temperature and precipitation over the coming decades, which is likely to impact vegetation dynamics and greenhouse gas exchange. To test this response, an experiment was installed at the Cape Bounty Arctic Watershed Observatory, on Melville Island, NU, in 2008 as part of the International Tundra Experiment (ITEX). Snow fences and open top chambers (OTCs) were used to manipulate snow depth and air temperature, respectively. Unlike most ITEX sites to date, enhanced temperature and snowfall were combined here in a factorial design with eight replicates. As an added control, four plots were established well outside the enhanced snow area. Senescence date was recorded at the end of the season, and at the peak of the growing season a vegetation survey was conducted within each plot in order to determine the total percent cover of each plot, as well as the percent cover of individual species. Carbon dioxide (CO2) exchange was also measured within each plot throughout the growing season. The date of senescence occurred significantly earlier in plots which had not been manipulated in any way, compared to all other treatments for all species. Salix arctica showed the greatest increase in cover over time at the species level. Lichen cover increased significantly in the deepened snow plots, and in general there were significant increases in percent cover in some functional groups over time. During June and into July the net CO2 flux was to the atmosphere. It was not until July 27 that these ecosystems became net carbon sinks. However, warming alone resulted in the ecosystem acting as a significant net carbon sink for the entire growing season. Plots exposed to warming alone were estimated to have removed approximately 19.94 g C m-2 from the atmosphere, whereas all other treatments were very similar to one another and estimated to have added approximately 3.12 g C m-2 to the atmosphere. Active layer depth and soil temperatures suggest that plots within the ambient snow zone may be receiving some additional snow due to their proximity to the fences. CO2 fluxes measured within the outer control plots suggest that the effect of warming alone could lead to this ecosystem being an even stronger net C sink under truly ambient snow conditions. M.Sc. |
author2 |
Scott, Neal Geography and Planning |
format |
Thesis |
author |
Arruda, Sean |
author_facet |
Arruda, Sean |
author_sort |
Arruda, Sean |
title |
Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem |
title_short |
Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem |
title_full |
Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem |
title_fullStr |
Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem |
title_full_unstemmed |
Impacts of Enhanced Temperature and Snow Deposition on Senescence Date, Vegetation Cover, and CO2 Exchange in a Canadian High Arctic Mesic Ecosystem |
title_sort |
impacts of enhanced temperature and snow deposition on senescence date, vegetation cover, and co2 exchange in a canadian high arctic mesic ecosystem |
publishDate |
2016 |
url |
http://hdl.handle.net/1974/15283 |
long_lat |
ENVELOPE(-109.542,-109.542,74.863,74.863) |
geographic |
Arctic Cape Bounty |
geographic_facet |
Arctic Cape Bounty |
genre |
Arctic Tundra Melville Island |
genre_facet |
Arctic Tundra Melville Island |
op_relation |
Canadian theses http://hdl.handle.net/1974/15283 |
op_rights |
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada ProQuest PhD and Master's Theses International Dissemination Agreement Intellectual Property Guidelines at Queen's University Copying and Preserving Your Thesis This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
_version_ |
1766328446898667520 |