Hydraulic redistribution and hydrological controls on aspen transpiration and establishment in peatlands following wildfire

Midori Depante, Matthew Q. Morison*, Richard M. Petrone, Kevin J. Devito, Nicholas Kettridge, James M. Waddington

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

In the sub-humid Western Boreal Plains of Alberta, where evapotranspiration often exceeds precipitation, trembling aspen (Populus tremuloides Michx.) uplands often depend on adjacent peatlands for water supply through hydraulic redistribution. Wildfire is common in the Boreal Plains, so the resilience of the transfer of water from peatlands to uplands through roots immediately following wildfire may have implications for aspen succession. The objective of this research was to characterize post-fire peatland-upland hydraulic connectivity and assess controls on aspen transpiration (as a measure of stress and productivity) among landscape topographic positions. In May 2011, a wildfire affected 90,000 ha of north central Alberta, including the Utikuma Region Study Area (URSA). Portions of an URSA glacio-fluval outwash lake catchment were burned, which included forests and a small peatland. Within 1 year after the fire, aspen were found to be growing in both the interior and margins of this peatland. Across recovering land units, transpiration varied along a topographic gradient of upland midslope (0.42 mm hr−1) > upland hilltop (0.29 mm hr−1) > margin (0.23 mm hr−1) > peatland (0.10 mm hr−1); similar trends were observed with leaf area and stem heights. Although volumetric water content was below field capacity, P. tremuloides were sustained through roots present, likely before fire, in peatland margins through hydraulic redistribution. Evidence for this was observed through the analysis of oxygen (δ18O) and hydrogen (δ2H) isotopes where upland xylem and peat core signatures were −10.0‰ and −117.8‰ and −9.2‰ and −114.0‰, respectively. This research highlights the potential importance of hydraulic redistribution to forest sustainability and recovery, in which the continued delivery of water may result in the encroachment of aspen into peatlands. As such, we suggest that through altering ecosystem services, peatland margins following fire may be at risk to aspen colonization during succession.

Original languageEnglish
Pages (from-to)2714-2728
Number of pages15
JournalHydrological Processes
Volume33
Issue number21
DOIs
Publication statusPublished - 15 Oct 2019

Bibliographical note

Funding Information:
Thank you to George Sutherland, Scott Brown, Corey Wells, and the University of Waterloo Environmental Isotope Laboratory for laboratory assistance and to Aryn Cain, Sarah Irvine, Hillary McDougall, Patrick Pow, and Greg Carron for assistance with fieldwork. This research was funded by a NSERC CRD Grant and a Research Grant from Syncrude Canada Ltd. and Canadian Natural Resources Ltd. to K. J. D., J. M. W., R. M. P. and N. K.

Publisher Copyright:
© 2019 John Wiley & Sons, Ltd.

Keywords

  • Aspen
  • boreal
  • forest recovery
  • hydraulic redistribution
  • peatland-upland interface
  • transpiration
  • Western Boreal Plains
  • wildfire

ASJC Scopus subject areas

  • Water Science and Technology

Fingerprint

Dive into the research topics of 'Hydraulic redistribution and hydrological controls on aspen transpiration and establishment in peatlands following wildfire'. Together they form a unique fingerprint.

Cite this