1:00 pm - 2:00 pm
Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Nina Vogt. This seminar is open to the general public to attend.
Thesis Topic: Influence of permafrost characteristics on vegetation change in Yukon and Northwest Territories, Canada
Zoom Link: https://zoom.us/j/95124515874?pwd=b2xjenpPUCtZaVh6c2xLcUExOHlGUT09 (Passcode: 169313)
Permafrost thaw is a significant contributor to landscape change and ecosystem disruption in northern systems. While previous studies have examined the impact of permafrost on vegetation change, few have investigated the connection of permafrost characteristics to the type and extent of vegetation change. Additionally, much of the literature investigating vegetation change due to permafrost thaw has been restricted to peatlands. This thesis investigates the impacts of permafrost thaw on vegetation characteristics and how permafrost characteristics may influence the type and severity of ecosystem change in the peatlands of Jean Marie River, Northwest Territories, and boreal forests of the Whitehorse and Kluane regions of Southern Yukon, Canada.
Ecological and geophysical field investigations were incorporated to examine how vegetation characteristics differ with permafrost thaw, how vegetation differences may indicate permafrost thaw, and what this may tell us about landscape transition and the availability of habitat for characteristic boreal species post-thaw. I hypothesized that post-thaw vegetation would shift to species supported by moister conditions and that permafrost characteristics would be linked to the type and extent of vegetation change. I further hypothesized that such changes could result in qualitative differences in the amount and distribution of future habitat available to woodland caribou (Rangifer tarandus tarandus) in these regions.
Ecosystems and permafrost conditions varied considerably across the three study areas in Jean Marie River, Greater Whitehorse, and Kluane. However, with permafrost degradation, vegetation across all study sites shifted from species supported by drier, intact permafrost conditions to those supported in wetter environments. In general, there was a loss of characteristic boreal forest species, including lichens (Cladina, Cladonia, Cetraria), berries (Vaccinium vitis-idaea, Empetrum nigrum, Shepherdia canadensis), and forbs (Lupinus arcticus, Galium boreale ), as well as loss of forest cover. Both permafrost characteristics and surrounding ecosystems influenced the shift of species. Type and severity of vegetation and ecosystem change appear to be linked to permafrost characteristics. Qualitative assessment suggests substantive implications from permafrost thaw for the amount and distribution of important seasonal habitats for woodland caribou in these systems, with related considerations of landscape connectivity for both boreal and northern mountain populations.
This research fills a critical knowledge gap in how ecosystems in northwestern Canada may transition with permafrost thaw and helps reduce uncertainties concerning potential landscape change associated with climate change.