Action: Replace blocks of vegetation after mining or peat extraction
Key messagesRead our guidance on Key messages before continuing
- Two studies evaluated the effects on peatland vegetation of replacing blocks of vegetation after mining or peat extraction. One study was in a bog and one was in a fen.
- Plant community composition (2 studies): Two studies, in a bog in the UK and a fen in Canada, reported that transplanted vegetation blocks retained their peatland vegetation community. In the UK, the community of the transplanted blocks did not change over time. In Canada, the community of replaced vegetation blocks remained similar to an undisturbed fen.
- Vegetation cover (2 studies): One before-and-after study in the UK reported that bare peat next to translocated bog vegetation developed vegetation cover (mainly grass/rush). Sphagnum moss cover declined in the translocated blocks. One site comparison study in Canada reported that replaced fen vegetation blocks retained similar Sphagnum and shrub cover to an undisturbed fen.
This intervention involves replacing blocks of peatland vegetation on a bare peat surface, such as that left behind after mining subsurface peat. In this way, the surface vegetation may recover much more quickly than if reassembled through colonization or planting individual plants. Blocks of introduced vegetation with an intact surface layer may help to regulate moisture.
The vegetation blocks should be cut from the upper 30 cm of natural peatlands. They may be cut from the mined peatland before mining begins, then kept aside during mining. This retention and replacement approach has its origins in the German Bunkerde concept (Money & Wheeler 1999) but is also known as ‘peat-block reclamation’ (Cagampan & Waddington 2008). Alternatively, vegetation blocks may be cut from another peatland area and transplanted to the damaged area, as in ‘bofedal transplants’ used in South America. Clearly, this damages the donor bog (although blocks could be sourced from peatlands destined to be destroyed by development).
Key peatland types where this action may be appropriate: bogs, fens/fen meadows, tropical peat swamps.
Related action: rewetting, because peatlands are often drained to allow peat extraction.
Cagampan J.P. & Waddington J.M. (2008) Moisture dynamics and hydrophysical properties of a transplanted acrotelm on a cutover peatland. Hydrological Processes, 22, 1776–1787.
Money R.P. & Wheeler B.D. (1999) Some critical questions concerning the restorability of raised bogs. Applied Vegetation Science, 2, 107–116.
Supporting evidence from individual studies
A before-and-after study in 1991–1997 in a historically mined blanket bog/heathland in England, UK (Standen & Owen 1999) reported that translocated bog vegetation retained its overall community composition whilst gaining new species, and that adjacent bare peat was colonized by herbs and bog-characteristic plants. These results were not tested for statistical significance. Over six years, translocated bog vegetation retained its overall bog-characteristic community (data reported as a graphical analysis). However, it did gain six additional plant species (before translocation: 15 species; six years after: 21 species) and abundance of fringed bog moss Sphagnum fimbriatum declined (in 15% of quadrats before translocation, but only 3% six years after). Bare peat between translocated strips was colonized by 28 plant species with 48% total vegetation cover, 21–31% grass/rush cover, 10–15% cover of heather Calluna vulgaris and 1–5% cover of five other bog-characteristic species. In 1991, sods (vegetation and 1 m of underlying peat) were cut from a blanket bog remnant. They were moved to eight 4 x 140 m trenches, dug in a site historically mined for coal. Dry peat was spread between the translocated strips. Plant species and vegetation cover were recorded in 1991 (before translocation) and 1997: in 100 quadrats (0.25 m2) in six translocated strips, and in 90 quadrats (1 m2) in three strips between.
A site comparison study in 2008–2009 in a fen in Ontario, Canada (Wilhelm et al. 2015) reported that plots where surface peat was replaced developed plant cover and community composition intermediate between hummocks and hollows of an undisturbed plot. These results were not tested for statistical significance. After one year, Sphagnum moss cover was higher in peat-replacement plots (22–35%) than in undisturbed hollows (8–19%), but lower than on undisturbed hummocks (100%). The same was true for shrubs (peat-replacement: 15–20%; undisturbed hollows: 10%; undisturbed hummocks: 50%). For peat-replacement plots, data were not provided separately for hollows and hummocks. Overall community data were reported as a graphical analysis. In April 2008, 30-cm-thick blocks of peat and vegetation were replaced on a 12 x 12 m plot after removal of the underlying peat. An undisturbed plot 80 m away provided a comparison. From May to July 2009, vegetation cover was estimated in 6–18 quadrats/plot, distributed evenly across hummocks and hollows.
- Standen V. & Owen M.J. (1999) An evaluation of the use of translocated blanket bog vegetation for heathland restoration. Applied Vegetation Science, 2, 181-188
- Wilhelm L.P., Morris P.J., Granath G. & Waddington J.M. (2015) Assessment of an integrated peat-harvesting and reclamation method: peatland-atmosphere carbon fluxes and vegetation recovery. Wetlands Ecology and Management, 23, 491-504