POTENTIAL INFLUENCE OF CLIMATE CHANGE ON ECOSYSTEMS WITHIN THE BOREAL PLAINS OF NORTHERN ALBERTA

The Boreal Plains region of northern Alberta is composed of a myriad of shallow ponds and peatlands interspersed within forested uplands. Within the existing sub-humid climate regime, these ecosystems exist under a delicate hydrologic balance due to the prevalence of water deficit conditions. In a future warmer climate, they may be particularly sensitive to changes in the timing and magnitude of precipitation (P), as well as increased potential evapotranspiration (PET) resulting from a warmer and extended growing season. Increases in the frequency of wildfire and northward migration of pests and diseases previously limited by the cold winter season may further combine to stress these ecosystems, with a significant potential for changes in the dominant vegetation. The long term viability of these ecosystems is both regionally and globally significant, as the ponds and peatlands provide important seasonal habitat for migratory birds and also contain a large carbon pool. Thus, there is a need to understand what hydrological changes may occur in response to climate change.

In this study, numerical simulations were used to examine the potential influence of climate change within a small watershed characteristic of the Boreal Plains of northern Alberta. The study was conducted at the Utikuma Region Study Area (URSA), located approximately 350 km northwest of Edmonton. The study area consists of a shallow pond-peatland complex situated within aspen forested uplands composed of deep glacial moraine materials.

A two-dimensional model was developed using the fully-integrated code HydroGeoSphere. The model was calibrated to a decade of hydrologic data that included both wet and dry periods. Predictive simulations were performed to the end of 2090 for eight climate change scenarios. The predictive simulations were driven by the atmospheric fluxes of P and PET that were derived from a long-term climatic dataset from within the region. Results of the climate change simulations were compared to an additional simulation that incorporated boundary inputs from the existing climatic regime. Simulations results indicate that the ecosystems within the Boreal Plains of northern Alberta may experience more frequent water stress conditions as the climate warms, with the pond shifting to an ephemeral feature in some scenarios.