Yi Wang, Richard Petrone (2022). Effects of microforms on the evaporation of peat-bryophyte-litter column in a montane peatland in Canadian Rocky Mountain. Proceedings of the GWF Annual Open Science Meeting, May 16-18, 2022.

Peatland microtopography contains hummocks (local high points) and hollows (local low points). Little is known about how the evaporation of peat (P), peat-bryophyte (BP), peat-litter (LP) and peat-bryophyte-litter (LBP) columns vary with peatland microforms. Whether there are fine-scale variations in peatland evaporation, and if they are critical when being upscaled to the entire peatland ecosystem is yet to be answered. Our study found that evaporation was significantly affected by the cover type (P, BP, LP or LBP) and the interaction effect of the cover type and microform, based on field evaporation experiments in a montane peatland in Canadian Rocky Mountains during the growing season of 2021. Mean daily evaporation of P-Hummock and P-Hollow was 14.16 and 11.76 g d-1, respectively; BP-Hommock and BP-Hollow is 9.57 and 14.38 g d-1, respectively; LBP-Hummock and LBP-Hollow is 9.44 and 9.91 g d-1, respectively; and evaporation of LP-Hummock and LP-Hollow is 5.68 and 7.64, respectively. Peatland microform indirectly affected evaporation by interacting with cover type, modifying the vertical profile of soil temperature, and changing the key environmental drivers of evaporation. Moreover, we tested the ability of two widely used models in modelling the spatial variation of peatland evaporation. We found that the Penman-Monteith (P-M) model and bryophyte layer model in the Atmosphere-Plant Exchange Simulator (APES) were able to yield satisfactory results based on field measurements of soil temperature and soil moisture. Our study provides valuable information supporting the evaluation on the hydrological state of peatland ecosystems.

AOSM2022 Mountain Water Futures First Author: Yi Wang, Hydrometeorology Research Group, University of Waterloo Additional Authors: Richard Petrone, Hydrometeorology Research Group, University of Waterloo