Abstract
Resiliency is an ecosystem’s capacity to withstand (or resist) change – resilient ecosystems are considered to be less vulnerable to change. Yukon’s Arctic region is experiencing some of the most rapid climate change in the world (IPCC 2007). Understanding an ecosystem's inherent resiliency, through stability of its plant community and ecological processes over a range of climatic conditions, will provide insight into its vulnerability to climate change. I propose that ecosystems that have overlapping climate ranges (hereby bioclimate envelopes) for contemporary and predicted future climate are less likely to experience a change in ecological processes. Ecosystems that overlap very little with a future climate are more likely to experience changes in ecological processes and may be vulnerable to climate change. Low to high ecosystem vulnerability could be mapped using an ecological basemap. A vulnerability map can be used to target study area for climate change research to test what makes an ecosystem resilient or vulnerable to climate change.
The primary objective of this study is to assess if a mapped ecological classification of Yukon's Arctic ecosystems be used to identify which ecosystems, given a particular possible future climate, will be vulnerable to climate change. To address this overarching objective, I ask three questions about the bioclimate envelope of ecosystems at the regional to local scale in Yukon's North Slope: (1) Do field verified ecosystems differ in their climatic relationships at a regional scale? (2) Does a recent climate period differ from a projected future climate for field verified ecosystems at a regional scale? (3) Do field verified and mapped ecosystems differ in their relationship to climatic variables at a local scale?
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Climate data used to describe the bioclimate envelope are two Climate Normal periods (1961-190 and 1980-2010) and 29 Intergovernmental Panel on Climate Change future climate scenarios generated by a downscaled climate model for years 2025, 2055 and 2085. Results show that bioclimate subzones (using confirmed ground plots) differ significantly (alpha = 0.05) by for the Climate Normal period 1961-1990. Bioclimate subzones also differ significantly across all climate models, for Climate Normals and future climate scenarios. Field confirmed local ecosystem (using a subset of confirmed ground plots for a mapped region of the North Slope) and random locations, differed in their climate enveloped across nearly all ecosystem units for the Climate Normal period 1961-1990. Most ecosystem units differed from each other within their "plot type" grouping (plot vs random).
I suggest that bioclimate envelopes could be a useful tool to understand how the climate envelope, associated with regionally mapped ecosystems, may change in the future. Applying this approach however, to the locally defined ecosystem unit and associated climate envelope, does not yield consistent results between field and random sites at the local scale. Additional work should include a multivariate analysis to consider the influence of climate and abiotic factors at the same time to understand the degree the climate envelope drives ecosystems at a local scale.
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