Open Collections

Abstract

Abandoned block-cut peatlands are typified by an alternating topography of mined trenches and raised baulks. Although these sites re-vegetate densely with native bog species, Sphagnum species characteristic of undisturbed bogs are conspicuously absent and peat accumulation has not recommenced. Ecological restoration of abandoned block-cut peatlands involves blocking remnant drainage ditches, “rewetting” the residual peat body to: 1) re-establish vegetation assemblages dominated by Sphagnum, and 2) re-establish the upper, hydrologically active layer (acrotelm) that characterizes intact peatlands. This study evaluates the progress towards achieving these goals in three rewetted block-cut sites in eastern Québec. Plant species composition, above-ground biomass, and accumulated organic matter data were collected from mined trenches within rewetted and non-rewetted sectors of the study sites and used for comparison with nearby undisturbed reference bogs. Comparisons of current patterns of community vegetation structure in rewetted and non-rewetted sectors of the study sites indicated that vegetation assemblages are strongly influenced by water table position. In areas where rewetting resulted in a water table position at or just above the peat surface, rapid community scale vegetation change occurred, with widespread mortality of vascular vegetation followed by recolonization by hydrophytic ericaceous and herbaceous species, and hollow/lawn Sphagnum species (