Working on 16 sites across the 3 protected areas involved in the project, Pennine PeatLIFE will restore 1353ha of eroding blanket bog using site-specific Sphagnum-based restoration techniques.
The Pennine PeatLIFE project uses five basic steps to restore bare peat. These steps have been developed and modified over several years and are based on other projects across the UK and Canada. The steps have been modified to suit the bogs of northern England.
The five basic steps to restoration are:
1) Hydrology – preventing erosion from water
2) Slopes – the re-profiling of steep slopes
3) Heather brash cutting and spreading
4) Re-start vegetation growth
5) Sphagnum re-establishment
The restoration of site hydrology is the crucial first step in restoring a bare peat site. Sites with active drainage channels will continue to erode making re-vegetation difficult to accomplish.
There are a variety of techniques that can be used to prevent running water causing further or new erosion within the site, these include:
Peat dams – If there is sufficient peat on site and it the gully is accessible to a digger peat can be taken from borrow pits and placed in the gullies. This is similar to grip blocking in that it will act as a leaky dam.
Coir Rolls/Heather bale dams – These are used on degraded peat sites to slow water movement in eroded gullies. They are best used in shallow water channels where peat is still present. They should be keyed into the eroded channel reduce water movement, hold water during drier months and trap sediment.
Stone dams – These are used on large gullies (over 2m wide) that have either a peat base or eroded down to the mineral layer. Stone is flown in by helicopter to avoid damaging the bog with vehicles and dropped along the gully in pre-determined locations to form dams. Stone dams trap sediment, slow water movement during high rainfall keeping the water on the peatland longer.
Wooden dams – These can be used when there is still peat at the bottom of the gully. They are constructed of hardwood planks and fencing posts. These are leaky dams that slow the water and slow water during high rainfall.
Steep slopes (greater than 45 o) can be re-profiled to speed up colonisation from the base. A digger is used to peel back vegetation on the top of the slope, re-profile the exposed peat and then replace the vegetation from the top back over the newly re-profiled slope.
Not all slopes can be re-profiled in this way. Access within peat haggs can be difficult and this technique is only used where the surrounding area is vegetated as not to cause unnecessary damage.
3) Heather Brash
Covering bare peat with sphagnum rich heather brash is a crucial part of restoration in Northern England. Heather brash acts as a mulch which is a seed source of new plants contained in the mulch, acts as an insulator to prevent frost heave and reduces the drying and erosion impact of wind.
The heather brash will also provide material for mosses to grow on.
Heather brash is typically sourced and cut as locally as possible and then airlifted to the restoration site as needed.
4) Re-vegetation growth
To encourage and speed up re-vegetation of bare peat a number of things can be added.
- Moorland mix of species typically found in the surrounding area including heather and wavy hair grass.
- Sphagnum moss can be added in the wetter areas of the site and this will help retain water and prevent the bare peat from drying out
- Whole plug planting, usually cotton grasses can be transplanted.
- Fertiliser and lime can be added in very small quantities to initially improve the soil conditions. This will give the colonising vegetation a much needed temporary boost but will not damage the surrounding bog vegetation.