Animal and vegetation patterns in natural and man-made bog pools: implications for restoration

Restore/create peatland vegetation using the moss layer transfer technique

A controlled, before-and-after, site comparison study in 1999–2003 in a historically mined bog and 92 natural bogs in Quebec, Canada (Mazerolle et al. 2006) reported that an area restored using the moss layer transfer technique developed greater vegetation cover than an unrestored area, and that vegetation in the restored area was more similar to that of natural bogs. These results were not tested for statistical significance. After four years, the restored area had 49% moss cover (vs unrestored: 2%; natural: 85%), 19% herb cover (unrestored: 8%; natural: 19%) and 8% shrub cover (unrestored: 13%; natural: 51%). In autumn 1999, 8.4 ha of historically mined bog were restored by levelling the surface, rewetting (blocking drainage ditches and building embankments), adding plant fragments from the surface of a nearby natural peatland, straw mulching, and phosphorous fertilization. An adjacent 3.1 ha was not restored. In August 2003, vegetation cover was recorded in 3 x 8 m quadrats: 32 in the restored area and 15 in the unrestored area. Vegetation cover in 92 nearby natural (unmined) bogs was recorded in 2000. This study was based on the same experimental set-up as (2) and (3).

(Summarised by: Nigel Taylor)

Excavate pools (without planting)

A replicated, before-and-after, site comparison study in 1999–2003 in four bogs in eastern Canada (Mazerolle et al. 2006) found that created pools developed vegetation cover within four years, but reported that this remained lower than cover in and around natural pools. Initially, the created pools contained no vegetation. After four years, Sphagnum moss cover had increased to 9% (vs 80% in natural pools), herb cover had increased to 5% (natural: 10%) and shrub cover had increased to 5% (natural: 27%). Comparisons with natural pools were not tested for statistical significance. In 1999, four 6 x 8.5 m pools were created in one historically mined bog by excavating and rewetting (blocking drainage ditches and building embankments). No vegetation was introduced to these, although the surrounding site was sown with bog vegetation fragments. In 2003, vegetation cover was recorded in 36 quadrats/pool, each 30 x 30 cm, along six bank-to-bank transects. Vegetation cover of 70 natural pools, in unmined parts of nearby bogs, was recorded in 1999 and 2000. This study was based on the same experimental set-up as (2).

(Summarised by: Nigel Taylor)

Directly plant peatland herbs

A replicated, controlled, before-and-after study in 1999–2003 in a historically mined bog in eastern Canada (Mazerolle et al. 2006) found that planting in and around created pools did not significantly affect vegetation cover. After four years, planted and unplanted pools had similar cover of Sphagnum moss (13 vs 9%), other mosses (3 vs 3%), herbs (3 vs 5%), shrubs (6 vs 5%). In 1999, eight 6 x 8.5 m pools were created by excavating and rewetting a bog (blocking ditches and building embankments). In 2000, four pools were planted with four herb species. Sphagnum moss was also introduced to the water column. The study does not distinguish between the effects of planting herbs and mosses. The other four pools were not planted, although bog vegetation fragments were spread onto the rest of the peatland. In 2003, vegetation cover was recorded in 36 quadrats/pool, each 30 x 30 cm, along six bank-to-bank transects.

(Summarised by: Nigel Taylor)

Add mosses to peatland surface

A replicated, controlled, before-and-after study in 1999–2003 in a historically mined bog in eastern Canada (Mazerolle et al. 2006) found that sowing Sphagnum moss (and herbs) into created pools did not significantly affect vegetation cover. After four years, planted and unplanted pools had similar cover of Sphagnum (13 vs 9%), other mosses (3 vs 3%), herbs (3 vs 5%) and shrubs (6 vs 5%). In 1999, eight 6 x 8.5 m pools were created by excavating and rewetting a bog (blocking ditches and building embankments). In 2000, four pools were sown with Sphagnum moss (introduced to the water column). Four herb species were also planted in and around these pools. The other four pools were not planted, although bog vegetation fragments were spread onto the rest of the peatland (see intervention Spread mixed vegetation onto peatland surface). In 2003, vegetation cover was recorded in 36 quadrats/pool, each 30 x 30 cm, along six bank-to-bank transects.

(Summarised by: Nigel Taylor)

Create ponds for amphibians

A replicated site-comparison study in 2000–2003 of eight created ponds in restored peatland near Québec, Canada (Mazerolle et al. 2006) found that within a year three of four species found in natural ponds were breeding in the created ponds. Wood frogs Rana sylvatica and green frogs Rana clamitans melanota were present in 60–88% of created ponds each year. Numbers were 1–5 times greater than in natural ponds for green frogs (tadpoles: 23 vs 2; frogs: 5 vs 1/100 trap nights) and wood frog tadpoles (127 vs 1). Numbers of wood frog adults to juveniles were similar (1 vs 1). Leopard frogs Rana pipiens were not found and American toads Bufo americanus only found in created ponds. In 2000, tadpole numbers were lower in the four ponds stocked with plants compared to those left to recolonize naturally; however, numbers were similar in 2001–2002. Amphibians were surveyed using minnow traps set for 1–3 consecutive nights/month in May-August, 2000–2003 (24–192 trap nights/pond/year). Vegetation, invertebrates and pH were also monitored. For comparison 10–12 ponds in each of three natural (mined) peatlands were also sampled in 1999 and 2000.