Plot Scale Evapotranspiration from Restored and Unrestored Extracted Peatlands
Abstract
Peat extraction severely alters peatland hydrology through active drainage and altered peat hydrophysical properties. Once extraction ceases, ecosystem recovery is limited due to low soil moisture and deep water tables. Peatland restoration aims to return hydrologic conditions to be similar to those in undisturbed, reference peatlands. Changes to water table position following the blockage of drainage ditches, and re-introduction of plant species post-restoration, will both alter ET. Yet, how ET evolves post-restoration in extracted peatlands is poorly understood, particularly at the plot scale. In this study, growing season relative humidity data collected using the closed chamber dynamic method was compiled from restored, unrestored, and natural peatland sites in Seba Beach, Alberta and Bois-des-Bel, Quebec. Time since restoration at these sites ranged from 1 year to 25 years. The objectives of this study were to i) assess differences in ET between the three site types, ii) assess the influence of time since restoration on ET, iii) evaluate the influence of environmental controls and vegetation communities on ET. When considering the random effects of the year and month of measurement, the restored sites had significantly higher ET (2.1 mm d-1) than the natural sites (1.8 mm d-1). There was a trend of increasing ET with time since restoration. Vascular plant and moss cover were important drivers of ET at the natural site, explaining 66% of the variation, but not at the restored or unrestored sites where hydrologic conditions were more important in driving ET. There were positive relationships between ET and water table depth at the unrestored and restored sites, and a negative relationship with soil moisture at the restored site. At all site types, soil temperature had a significant positive relationship with ET. Understanding the drivers of ET will help us better predict restored peatland water balance at the plot scale under a changing climate.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMB025...13H
- Keywords:
-
- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCES;
- 0428 Carbon cycling;
- BIOGEOSCIENCES;
- 0497 Wetlands;
- BIOGEOSCIENCES;
- 1813 Eco-hydrology;
- HYDROLOGY