Permafrost thaw and ecosystem change

At high latitudes, permafrost conditions are fundamental to the ecology of boreal and tundra ecosystems. As such, the rapid warming and associated changes in permafrost conditions directly impact the composition, health and function of ecological communities. However, these communities in turn directly impact water and energy balances of the system resulting in complex interactions between climatic, hydrological, and ecological responses of ecosystems to warming. The Taiga Plains Ecoregion is ideally suited for the study of ecosystem responses to climate warming since it covers >50% of the NWT continental land mass over a wide latitudinal range, and therefore includes a wide range of permafrost characteristics. Furthermore, this region is home to a large proportion of the Northwest Territories’ population thus understanding the implications of climate warming-related changes in this region is critical for successful climate change adaptation planning in the NWT. Widespread ecosystem changes occurring as a consequence of climate warming and human disturbance, include but are not limited to: permafrost thaw-induced conversion of forests to wetlands on discontinuous permafrost and a greening of the tundra via shrub expansion promoted by active layer warming and thickening on continuous permafrost. Ongoing efforts include (1) the quantification of boreal forest responses to permafrost thaw across latitudes and examination of the mechanism underlying these responses; and (2) interactions between permafrost conditions and natural disturbance agents in determining the distribution, structure, and function of vegetation communities.