Permafrost disturbances, including active layer detachments (ALDs), have occurred both recently and historically at Cape Bounty, Melville Island. These recent and relict ALDs were studied to determine their short- and long-term landscape effects. Six relict detachments showed altered vegetation and site characteristics, despite 60 or more years of recovery. Of the environmental variables studied, including soil moisture, soil temperature, and active layer depth, soil moisture showed the greatest changes in disturbed zones. These were attributed to the concavity of disturbance, which allows for more snow accumulation. Two vegetation types influenced by moisture regimes, polar
desert and mesic heath, were compared to determine the role of moisture in recovery.
The best indicators of disturbance differed in areas of different moisture regimes, with
canopy height showing increases in disturbed mesic heath zones, while Normalized
Difference Vegetation Index (NDVI) values increased in polar desert disturbances.
Ultimately, the comparison of vegetation in disturbed and undisturbed zones revealed
differences to be highly localized and minimal. Remote sensing was utilized to compare the effects of recent and relict disturbances as seen on satellite and airborne imagery. Vegetation was classified using NDVI, and zonal separation of these values in ALDs revealed the upper scar areas and lower toe zones contained significantly different NDVI values. The upper scar values were similar to undisturbed control areas, as blocks of vegetation in these areas often contain unmodified vegetation, which later helps with revegetation. The lower toe zone displayed both elevated and lower NDVI values, as material accumulates in these areas but often in a complex with bare soil. Remote sensing techniques also allowed for site characterization of disturbances, with
physiographic factors including slope and flow properties determined through satellite
imagery. Slope values ranged from 3 to 13 degrees in each disturbance, but were found
to be slightly lower in relict disturbances, as recovery and revegetation have reduced
these slopes. Flow paths were identified in ALDs, however similar patterns were also
identified in surrounding undisturbed landscapes. Given the small scale of many ALDs, it is difficult to characterize the nature of the changes associated with these events, particularly for relict ALDs. / Thesis (Master, Geography) -- Queen's University, 2011-07-28 11:42:47.636
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/6629 |
| Date | 10 August 2011 |
| Creators | CASSIDY, ALISON ELIZABETH |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | 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. |
| Relation | Canadian theses |
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