Vulnerability of peatland complexes in the Hudson Plains, Canada to permafrost-thaw-driven hydrological change

Abstract

<p>Thawing discontinuous permafrost in subarctic peatland-dominated landscapes is increasingly recognized as an indicator of a warming climate and potentially shifting these landscapes from atmospheric carbon store to source. Furthermore, in certain discontinuous permafrost landscapes (e.g., northwest Canada) the thaw of permafrost peatlands leads to a reorganization of near-surface flow paths as permafrost-free peatlands expand, connect, merge, and drain. Collectively, these permafrost-thaw-driven landcover and hydrological changes have increased runoff and altered biogeochemical cycles threatening natural resources and critical infrastructure in Indigenous peoples’ traditional territories along with aquatic and terrestrial wildlife habitat. Owing to the region’s remote position and vast scale, comparatively less is known about the landcover and hydrological impacts of permafrost thaw in the Hudson Plains, the world’s third largest peatland region (370,000 km<sup>2</sup>) and southern most extent continental permafrost. For this study, we assign specific hydrological functions to individual peatland types based on their form, to then infer hydrological flux and storage processes within and between peatlands un a circuitry analog, at the scale of the peatland complexes and peatland complex regions. We analyze several remotely sensed data, including high-resolution lidar, historical air photographs, and recent panchromatic and multispectral satellite imagery along a latitudinal transect to evaluate peatland form, complex, and regional patterns. We then summarise these results and interpretation to present an initial vulnerability map of peatland complexes in the Hudson Plains to permafrost-thaw-driven hydrological change.  </p>