Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales.
Climate change will affect Arctic plant communities directly, by altering growth and recruitment, and indirectly, by increasing the frequency of natural disturbance. Since the structure of northern vegetation influences global climate, understanding both temperature and disturbance effects on vegeta...
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ftunivbritcolcir:oai:circle.library.ubc.ca:2429/1240 2023-05-15T14:46:42+02:00 Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. Lantz, Trevor Charles 2008 2693840 bytes application/pdf http://hdl.handle.net/2429/1240 eng eng University of British Columbia Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Plant ecology Arctic vegetation Temperature impact Text Thesis/Dissertation 2008 ftunivbritcolcir 2019-10-15T17:43:39Z Climate change will affect Arctic plant communities directly, by altering growth and recruitment, and indirectly, by increasing the frequency of natural disturbance. Since the structure of northern vegetation influences global climate, understanding both temperature and disturbance effects on vegetation is critical. Here, I investigate the influence of temperature and disturbance on Low Arctic vegetation at several spatio-temporal scales in the Mackenzie Delta Region, N.W.T. To disentangle the relative impact of temperature and disturbance on forest-tundra and tundra ecosystems, I sampled microenvironmental variability, plant community composition, and green alder abundance, growth, and reproduction on disturbed (burns and thaw slumps) and undisturbed sites across a regional temperature gradient. Disturbed areas showed increases in alder productivity, catkin production, and seed viability, as well as differences in plant community composition and microenvironment. The magnitude of plot-level responses to disturbance compared to variation across the temperature gradient suggests that in the short-term, increasing the frequency of disturbance may exert a stronger influence on tundra ecosystems than changes in temperature. At the plot level, increases in alder seed viability and recruitment at warmer sites point to the fine-scale mechanisms by which shrub abundance will change. To examine the relative influence of temperature and biophysical variables on landscape-level patterns of shrub dominance, I mapped Low Arctic vegetation using aerial photos. At this broader scale, correlations between temperature and the areal extent of shrub tundra suggest that warming will increase the dominance of shrub tundra. To assess the magnitude of changes in temperature and thaw slump activity, I analyzed climate records and mapped retrogressive thaw slumps using aerial photographs. An increase in thaw slump activity in recent decades, coincident with higher temperatures, suggests that continued warming will change the area affected by thermokarst disturbances like slumps. Taken together, my research indicates that the effects climate change will be magnified by shifts in the frequency of disturbance, initiating changes to Arctic vegetation with significant implications for global climate. My work also shows that to fully understand the influence of patch-landscape feedbacks on Arctic vegetation dynamics, the effects of disturbance must be examined across longer temporal and broader spatial scales. Forestry, Faculty of Graduate Thesis Arctic Climate change Mackenzie Delta Thermokarst Tundra University of British Columbia: cIRcle - UBC's Information Repository Arctic Mackenzie Delta ENVELOPE(-136.672,-136.672,68.833,68.833) |
institution |
Open Polar |
collection |
University of British Columbia: cIRcle - UBC's Information Repository |
op_collection_id |
ftunivbritcolcir |
language |
English |
topic |
Plant ecology Arctic vegetation Temperature impact |
spellingShingle |
Plant ecology Arctic vegetation Temperature impact Lantz, Trevor Charles Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. |
topic_facet |
Plant ecology Arctic vegetation Temperature impact |
description |
Climate change will affect Arctic plant communities directly, by altering growth and recruitment, and indirectly, by increasing the frequency of natural disturbance. Since the structure of northern vegetation influences global climate, understanding both temperature and disturbance effects on vegetation is critical. Here, I investigate the influence of temperature and disturbance on Low Arctic vegetation at several spatio-temporal scales in the Mackenzie Delta Region, N.W.T. To disentangle the relative impact of temperature and disturbance on forest-tundra and tundra ecosystems, I sampled microenvironmental variability, plant community composition, and green alder abundance, growth, and reproduction on disturbed (burns and thaw slumps) and undisturbed sites across a regional temperature gradient. Disturbed areas showed increases in alder productivity, catkin production, and seed viability, as well as differences in plant community composition and microenvironment. The magnitude of plot-level responses to disturbance compared to variation across the temperature gradient suggests that in the short-term, increasing the frequency of disturbance may exert a stronger influence on tundra ecosystems than changes in temperature. At the plot level, increases in alder seed viability and recruitment at warmer sites point to the fine-scale mechanisms by which shrub abundance will change. To examine the relative influence of temperature and biophysical variables on landscape-level patterns of shrub dominance, I mapped Low Arctic vegetation using aerial photos. At this broader scale, correlations between temperature and the areal extent of shrub tundra suggest that warming will increase the dominance of shrub tundra. To assess the magnitude of changes in temperature and thaw slump activity, I analyzed climate records and mapped retrogressive thaw slumps using aerial photographs. An increase in thaw slump activity in recent decades, coincident with higher temperatures, suggests that continued warming will change the area affected by thermokarst disturbances like slumps. Taken together, my research indicates that the effects climate change will be magnified by shifts in the frequency of disturbance, initiating changes to Arctic vegetation with significant implications for global climate. My work also shows that to fully understand the influence of patch-landscape feedbacks on Arctic vegetation dynamics, the effects of disturbance must be examined across longer temporal and broader spatial scales. Forestry, Faculty of Graduate |
format |
Thesis |
author |
Lantz, Trevor Charles |
author_facet |
Lantz, Trevor Charles |
author_sort |
Lantz, Trevor Charles |
title |
Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. |
title_short |
Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. |
title_full |
Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. |
title_fullStr |
Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. |
title_full_unstemmed |
Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales. |
title_sort |
relative influence of temperature and disturbance on vegetation dynamics in the low arctic : an investigation at multiple scales. |
publisher |
University of British Columbia |
publishDate |
2008 |
url |
http://hdl.handle.net/2429/1240 |
long_lat |
ENVELOPE(-136.672,-136.672,68.833,68.833) |
geographic |
Arctic Mackenzie Delta |
geographic_facet |
Arctic Mackenzie Delta |
genre |
Arctic Climate change Mackenzie Delta Thermokarst Tundra |
genre_facet |
Arctic Climate change Mackenzie Delta Thermokarst Tundra |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
_version_ |
1766317894417776640 |