Trembling Aspen (Populus tremuloides) Transpiration and Recovery Post-fire Disturbance in the Western Boreal Plains of Alberta

Midori Depante, University of Waterloo, Waterloo, ON, Canada, Richard M Petrone, University of Waterloo, Geography and Environmental Management, Waterloo, ON, Canada, Kevin Devito, University of Alberta, Edmonton, AB, Canada, Nicholas Kettridge, University of Birmingham, School of Geography, Earth & Environ. Sciences,, Birmingham, United Kingdom and James Michael Waddington, McMaster University, Hamilton, ON, Canada

Contact First Author: Midori Depante; mdepante@uwaterloo.ca

Abstract ID#: 34219

 

English Abstract:
The Western Boreal Plains of Canada (WBP) is characterized by a sub-humid climate where evapotranspiration often exceeds precipitation, highlighting the importance of the interactions between peatlands that hydrologically feed uplands. The connectivity between both land units can also be attributed to trembling aspen (Populus tremuloides) clones and rooting systems that aid in hydraulic redistribution, though this process has not been linked to aspen roots found in peatlands. The objectives of this study are: 1) to understand why aspen, an upland tree species, exist in peatlands post-fire, and 2) to determine the contribution of aspen roots in peatlands to the early recovery of burned sites in the WBP. Aspen leaf stomatal conductance was measured daily across a burned upland-peatland gradient in the Utikuma Research Study Area (URSA) in north central Alberta two years post-fire. Aspen transpiration (mm s-1) in peatlands was particularly of interest since they are not known to establish in peat after disturbance. In the same plots, plant tissue and soil was also collected and analyzed for 18-oxygen (δ18O) and deuterium (δ2H) composition to determine the water source for regenerating aspen. While usually stressed in waterlogged soils, the results showed that aspen transpiration did not significantly differ across each land unit regardless of differences in leaf area and soil moisture. Furthermore, δ18O/ δ2H signatures of pore water and plant tissue of aspen found in peatlands indicate the uptake of peat water through aspen rooting systems and hydraulic redistribution to the adjacent land units. Although the long-term effect of aspen transpiration and water usage in peatlands remains unknown, this study demonstrates that aspen can withstand wetland soils which aids in the hydrologic connectivity between peatlands and uplands needed during the early recovery of naturally and anthropogenically disturbed sites.
Back to: Advances in Wetland Ecohydrology