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Dartmoor Mires Project

Restoration

The Dartmoor Mires Project aims to explore the effects of restoration on around 100 hectares of high quality blanket bog, using experimental, low-key gully-blocking techniques to reduce erosion and promote regeneration of moorland bog vegetation. In consultation with project partners four areas have been identified as potential sites for pilot restoration. They are all within the northern part of the Forest of Dartmoor and located above 500m on relatively flat plateaux. They are all subject to erosion encroaching onto high quality blanket bog on peat up to seven meters in depth. For more information on these sites please see the briefing note on selection of candidate sites below, or see the site profiles.

Briefing note on selection of candidate sites

During August and October 2013 we carried out restoration works on damaged blanket bog at South Tavy Head, an area of blanket bog within the Merrivale firing range, on high plateau, just north of Cowsic Head.  Some final surveying of the work carried out is required, however if successful, we expect these works should hydrologically restore 9.5ha of blanket bog. Including the restoration works we completed at Winney’s Down Area 1 in 2011 and 2012, and the works at Winney’s Down Area 2 in 2012, we have now, if successful, restored approximately 44.5ha of blanket bog.

Our next phase of restoration works will begin next summer at Flat Tor Pan, an area of blanket bog immediately south east of Flat Tor. This site represents our largest restoration area which, if successful, will hydrologically restore around 58ha. This area is also home to our hydrological monitoring equipment, and restoration will enable us to record invaluable data on the effects of restoration on the hydrology and erosion on this site.

Flat Tor Pan will be the last site to be restored in the current 5 year pilot phase of the project. However, it is hoped that the experience gained at these four sites, and the data gathered from the extensive monitoring programme set up during this pilot project, will enable us to assess the feasibility and potential for further work to help protect Dartmoor’s peatlands.

Why is restoration work necessary?

At these sites erosion can be seen on the ground as networks of gullies. Where these are more pronounced irregular lumps of bare peat topped with modified vegetation, may be seen. These are known as hags and may be 2m high or more, demonstrating the quantity of peat which has eroded from around them. There is often little, or only modified vegetation in the gullies, and generally just bare peat. The vegetation around the gullies is also modified with reduced presence of characteristic bog plants such as sphagnum moss and cotton grass, and increased presence of coarse species such as purple moor grass and deer grass. The gullies help water to run quickly off the bog and contribute to a lowered water table, erosion, and oxidisation of the peat.

What form does the restoration take?

The restoration aims to slow, and ideally reverse, peat loss. To achieve this, peat from within and immediately around the gullies is used to form numerous small blocks across the gullies. Rainwater is held behind these blocks forming a series of small shallow pools. This enables the water-table to recover in previously degraded areas, and protects the bog from being damaged, where it is still in good condition. These pools provide ideal conditions for bog plants to recolonise naturally.

At all sites, only peat/peat turves are currently used to form the blocks within the gullies, this ensures a low impact, unobtrusive result. The exception may be a small number of blocks at Flat Tor Pan, which is yet to be restored, where wood may be used to support the peat blocks immediately around some of the hydrological monitoring equipment. As far as possible, vegetation tops all of the created blocks. The aim is that, following rain, all remaining unvegetated peat is covered by water (see photo below). The performance of this peat-only technique will be assessed and monitored over future years. If it is successful then it will be used in other areas where similar erosion is threatening the blanket bog.

Blanket bog on Winney’s Down before (left) and after (right) restorationDartmoor mires

How much restoration has been completed to date?

To date we have undertaken restoration works at two sites, both at Winney’s Down. Restoration began on Winney’s Down Area 1 in 2011, and was completed in a second round of works 2012. These works also saw the restoration of Winney’s Down Area 2. In total (and if successful) these works have hydrologically restored 35 hectares of blanket bog on Dartmoor. The term ‘hydrologically restored area’ refers to an area of blanket bog, beyond and including the worked area, which is protected as a result of the restoration works. For more information on this please see our briefing note on Hydrological Restored Areas below:

Briefing note on Hydrologically Restored Area

We are currently developing a work plan for next autumn’s restoration works in consultation with our project partners.

Who undertakes the work?

Mires restorationThe restoration plans are developed by the Dartmoor Mires Project staff in consultation with Natural England, the Environment Agency, Dartmoor National Park Authority Dartmoor Commoners’ Council, Forest of Dartmoor Commoners’ Association and the Duchy of Cornwall.

A wider range of partners also ensured that historic, biodiversity, recreation, and military interests had been taken into account, whilst restoration proposals are developed with assistance from the Forest of Dartmoor commoners, whose stock graze the sites.

The restoration is undertaken by contractors under the constant supervision of Dartmoor Mires Project staff, who are present on site at all times whilst the work is underway. The restoration utilises machinery which is specially constructed for work on bogs. It has specially designed tracks and exerts extremely low ground pressure to stop it from damaging the surface of the bog.

Visiting the sites

There are no restrictions from visiting the sites but please avoid stepping in pools and on any unvegetated, bare peat areas. Please be aware that some of our sites are within the MOD ranges and as such will be subject to access restrictions on firing days. Please visit the MOD page for details of firing days.

Site profiles

view an interactive map of the restoration sites  View the mires map

Winney’s Down area 1

Restoration on Winney’s Down area 1 was completed in September 2012 having started in 2011 as our initial site. The site is west of Fernworthy plantation, immediately south of Statt’s House, at approx OSGR SX625820. The effects of works are visible on 9 ha of the site, however if successful 20ha of blanket bog will be hydrologically restored.

Anything of interest?

Winneys Down area 1 is a great place to see Sphagnum magellanicum. This, often bright red, moss is an important peat building species associated with higher quality sites. It is also a good place to spot Black Darter dragonflies (Sympetrum danae) which lay their eggs in the sphagnum pools on the blanket bog.

This site also has some of the deepest peat recorded on all of our restoration sites, measured at 6.7m at one location, but know to be at least 5m deep across a wider area.

Winney’s Down area 2

Restoration on Winneys Down area 2 was undertaken during Autumn 2012. This site is located about half a mile northwest of Winneys Down area 1 beyond Statts House at OSGR SX616826. The effects of works are visible on around 4.5ha of the site, however if successful 15ha of blanket bog will be hydrologically restored.

Anything of interest?

This site boasts a wide range of the sphagnum species common on Dartmoor’s blanket bogs. In particular Sphagnum denticulatum is common in the bog pools; this can often be identified by the curved branches that give it its common name Cow-horn bog-moss.

Prior to works in 2012 a palaeoecological survey was commissioned for Winney’s Down area 2. This report revealed that peat formation was not uniform across the site, with peat onset beginning at different times. It also revealed peat depths between 1.35 to 5.45m across the site.

Flat Tor Pan (Broad Down)

Flat Tor Pan (referred to variously elsewhere as Broad Down, Wildbanks Mire, and Wildbanks Hill) is currently scheduled for restoration in summer/autumn 2014. It is located southeast of Flat Tor at OSGR SX613812. Works are planned on around 10ha of the site, and it is estimated these works will hydrologically restore 58ha of blanket bog.

Anything of interest? Flat Tor Pan is the site of the Hydrological monitoring equipment installed and managed by Exeter University. This equipment is gathering data on ground water levels, water flow and quality, and CO2 emissions. This data once analysed will provide invaluable evidence on the value of the restoration work. For more information please visit our research and monitoring page. The equipment is held within two small enclosures to protect it from livestock. If you wish to visit the Flat Tor Pan site we request that you do not enter these enclosures as the equipment is very sensitive and footfall may affect readings.

Flat Tor Pan also contains the scars and debris leftover from a plane crash. On 31 May 1965 during a training flight, a Sea Vixen from 776 Royal Navy Air Squadron, crashed on the site. Luckily the pilot and his observer managed to eject safely before the plane crashed. After the crash the larger parts of the fuselage were removed by the military, however a few small pieces of twisted metal and wire lie scattered over the surface of the bog. The site of the crash is now a large pond located on the northern side of the restoration area.

South Tavy Head

South Tavy Head lies about a 1km north of Devil Tor at OSGR SX597807 and is located within the Merrivale firing range. The site is a small part of a large blanket of peat which stretches from Cowsic head up to Cut Hill and across to Walkham Head. Restoration works were carried out at this site in August and October in 2013 and it is estimated, if successful, will have hydrologically restored around 9.5ha of blanket bog.

Anything of interest?

South Tavy Head is in the middle of a very extensive area of blanket bog on the north moor of Dartmoor. It contains characteristic hummock and hollow bog pools, however much of this is now degraded. South Tavy Head is in one of the most remote areas of Dartmoor and provides a real sense of isolation.
Page last updated: 15 Apr 2014