Control of Short-Stature Vegetation Type on Shallow Ground Temperatures in Permafrost Across the Eastern Canadian Arctic

Abstract

The Arctic has warmed three times the rate of the global average, resulting in extensive thaw of perennially frozen ground known as permafrost. While it is well understood that permafrost thaw will continue and likely accelerate, thaw rates are nonuniform due, in part, to the expansion of Arctic trees and tall shrubs that may increase ground temperatures. However, in permafrost regions with short-stature vegetation (height < 40 cm), our understanding of how ground temperature regimes vary by vegetation type is limited as these sites are generally found in remote high-latitude regions that lack in situ ground temperature measurements. This study aims to overcome this limitation by leveraging in situ shallow ground temperatures, remote sensing observations, and topographic parameters across 22 sites with varying types of short-stature vegetation on Baffin Island, Canada, a remote region underlain by rapidly warming continuous permafrost. Results suggest that the type of short-stature vegetation does not necessarily correspond to a distinct shallow ground temperature regime. Instead, in permafrost regions with short-stature vegetation, factors that control snow duration, such as microtopography, may have a larger effect on evolving ground temperature regimes and thus permafrost vulnerability. These findings suggest that anticipating permafrost thaw in regions of short-stature vegetation may be more nuanced than previously suggested.