The hydrology of the Bois‐des‐Bel peatland restoration: hydrophysical properties limiting connectivity between regenerated Sphagnum and remnant vacuum harvested peat deposit

Abstract

AbstractThe Bois‐des‐Bel peatland was restored in the winter of 1999; since then, an ~15–20 cm Sphagnum moss carpet has regenerated over the site, but it is currently unknown how the structure of the regenerated Sphagnum moss and cutover peat influences the hydrology of Bois‐des‐Bel. This study evaluates the hydrophysical properties of Bois‐des‐Bel, based on a combination of field and monolith experiments at a restored (RES), natural (NAT) and unrestored (UNR) site. The lowest field soil moisture in the Sphagnum moss at RES was 0.09 cm3 cm−3, while 0.20 cm3 cm−3 at NAT. These results were similar in both the monolith experiments and individual core hydraulic parameterization (i.e. soil water retention and unsaturated hydraulic conductivity). The low soil moisture and relatively abundant large pores (>397 µm) in the RES Sphagnum resulted in low unsaturated hydraulic conductivity (0·23 cm day−1 at ψ = −35 cm) and high specific yield (0·45) compared with NAT Sphagnum (1·2 cm day−1 and 0·10, respectively). The abundance of large pores at RES resulted in hydrological conditions dissimilar to NAT and limited connectivity with the cutover peat, the latter being similar to UNR. To negate the implications of limited connectivity on water transfer from the cutover peat to the regenerated Sphagnum, the water table would need to fluctuate almost entirely within the regenerated Sphagnum layer. This will occur in time, as decomposition and compression cause a decrease in average pore size of the regenerated moss, thus detaining water and resulting in a higher water table. Copyright © 2014 John Wiley & Sons, Ltd.