The excavation of shallow peat basins enhances establishment of the Sphagnum mosses at a cutover peatland in the Lac-Saint-Jean region, Québec, Canada
Published source details
Campeau S., Rochefort L. & Price J.S. (2004) On the use of shallow basins to restore cutover peatlands: plant establishment. Restoration Ecology, 12, 471-482
Published source details Campeau S., Rochefort L. & Price J.S. (2004) On the use of shallow basins to restore cutover peatlands: plant establishment. Restoration Ecology, 12, 471-482
Since the early 1990s, techniques have been developed to re-establish plant communities lost from harvested peatlands in Canada. These techniques include reintroduction of plants, restoring hydrology and the use of straw mulch to improve surface conditions. This study examined the effectiveness of using shallow (20 cm deep) basins of various widths to improve the success of Sphagnum moss establishment.
Study area: The study was undertaken on a cutover portion of peatland in the Lac-Saint-Jean region, Québec, Canada. The area was drained and in 1991–1992 the upper 0.35–0.6 m was removed by block cutting. This resulted in no plant diaspore left with extensive areas of bare peat. To restore water levels, drainage ditches were blocked in 1993–1994. Residual peat (thickness 1.2 to 1.8 m) had suffered oxidation and subsidence due to drainage and cutting activities.
Experimental design: The objective was to compare establishment of three species of Sphagnum between basins and adjacent flat surfaces. In spring 1996, eight, 8 × 12 m plots were marked out on two peat fields. Four were left untouched, and four excavated in spring 1996 to form shallow basins using a bulldozer. The surface peat was scraped down to the frozen layer (20–25 cm), and the spoil pushed into ridges bordering the basin sides. Each main plot was divided into three 8 × 4 m subplots.
Within each plot, one of the subplots was sown with Sphagnum fuscum, a second S.magellanicum, and the third S.rubellum (= S.capillifolium) diaspores. These mosses were collected by hand in early May 1996 from two nearby natural peatlands. The moss was handsown at a 1:10 ratio (1 m² surface collected in the natural area spread over 10 m² of experimental surface). All plots were covered with straw mulch after sowing.
Sphagnum establishment: The shallow basins enhanced establishment of the three Sphagnum species. At the end of the fourth growing season, there was significantly higher moss cover in the basins than on the flats. No significant differences in cover were observed among species in basins, but S.magellanicum had a lower success establishing on flat surfaces than the two other species.
The higher Sphagnum cover in basins was compensated partly by better establishment of other mosses, mainly Polytrichum strictum, on the flats (average cover in basins 2%; on flats 5%). Despite this, the average bryophyte cover in basins (61%) greatly exceeded that on flats (24%) after four growing seasons. Vascular plant cover was similar between basins and flats after four growing seasons (average cover 5%).
Conclusions: The use of basins resulted in wetter conditions which enhanced Sphagnum development. Basins were flooded temporarily each spring during snowmelt, and in summer and autumn following heavy rain. In contrast, flat surfaces were almost never covered with water or, if so, only very locally. Results of this experiment demonstrate that the basins were generally effective at promoting Sphagnum establishment.
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