Ecological Briefing Notes 2020

20th Jan 2020

Ourea Events races are located in Britain’s greatest upland areas that often contain features of outstanding biodiversity value and importance. Occasionally, the features that provide this interest can be vulnerable to the wear and tear that may result from the passage of event participants. The risk of ecological damage is carefully assessed during early stages in the planning process for each event, when every effort is made to avoid sensitive ecological interest areas that could be disturbed by the event. 


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Marmot Dark Mountains visits some of Britain’s greatest upland areas​ ©Steve Ashworth


We are keen to encourage personal route selection choices by participants on our events to further avoid the risk of local ecological disturbance. This Ecological Briefing Note has been prepared for the 2020 Marmot Dark Mountains event to identify key ecological interest features that contribute to the special character of the event area, with route selection comments to help minimise the risk of localised ecological disturbance.

The 2020 Marmot Dark Mountains event area is located within the northern Snowdonia National Park east of Blaenau Ffestiniog. The countryside within this area has a remote, wild character with areas of extensive dissected upland plateau landscape and areas of greater topographical variety where glacial action towards the eastern end of the event area has formed a complex of hills and steep-sided valley landforms.

The glaciated landforms and upland character of the area has produced a range of nature conservation interest sites. Those recognised by statutory designations comprise three areas of international nature conservation importance, and two sites of national nature conservation importance. 

One designated site extends across a substantial part of the event area, containing a varied assemblage of upland wildlife habitats, including a location of particular importance for the conservation of montane heath, and habitats that are used by three rare species of upland breeding birds. The designated site also includes one of the largest tracts of intact blanket bog habitat in Wales. 

The event area is crossed by a considerable number of existing hill paths and tracks, and use of these by Marmot Dark Mountains participants will help to avoid trampling disturbance of fragile upland habitats. Where courses require movement across hill land between paths and tracks this ecological briefing note provides recommendations for personal route choices that will help to avoid the risk of significant ecological disturbance. This ecological briefing note has also been produced to communicate the special upland environmental interest of the event area to enrich the experience of participating in the Marmot Dark Mountains event.


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Using existing hill paths and tracks ©Steve Ashworth


  • Dry acid grassland is a relatively widespread vegetation type within the event area, where centuries of livestock grazing has converted heather moorland to open grassland. These areas provide a relatively robust vegetation type that can generally withstand the trampling effects of hill running. 


  • Extensive areas of dry acid grassland in upland areas can include mosaics of other upland vegetation types such as blanket bog, heather-dominated heath vegetation and wet acid grassland creating areas of local vulnerability to a concentration of trampling by Marmot Dark Mountains participants. 


  • Blanket bog is an important habitat within the event area that includes one of the most extensive tracts of high-quality blanket bog habitat in Wales. Some of these areas include degraded blanket bog where bog vegetation has been lost and peat erosion gulleys have formed where the underlying peat is being eroded. 


  • Disturbance of blanket bog by runners churning through peat hags has the potential to trigger further peat erosion by de-stabilising the peat surface. Wherever possible, route choices in these areas should try to link strips and patches of surviving moorland vegetation between the peat hags. These are often quite well-drained, providing areas of relatively robust vegetation and resistant to the trampling effects of running.


  • In contrast to areas of degraded blanket bog, extensive areas on plateau landforms and valley bottoms within the event area contain high quality blanket bog with an intact vegetation surface that lack eroding peat hags. These are typified by areas of wet heath vegetation interspersed with shallow pools, often associated with Sphagnum mosses. These areas often comprise a mosaic of vegetation types that will include slightly raised areas of better drained peat with drier heather moorland vegetation. These will be far less vulnerable to disturbance through vegetation damage by trampling and should ideally be selected when making route choices for running through these intact blanket bog areas.


  • Areas of wet acid grassland will be encountered where impeded drainage occurs within relatively level hill grassland areas or where groundwater emerges at the surface as seepages across more steeply sloping ground. Wet acid grassland can be of special nature conservation interest, in particular where groundwater seepages provide conditions for communities of specialised mosses, liverworts and other specialised plants. These vegetation types can be vulnerable to persistent disturbance effects of trampling and should ideally be avoided wherever possible by selecting routes that keep to dry acid grassland to by-pass wet grassland patches.


  • Wet acid grassland at groundwater seepages on steep ground can be difficult to avoid where they cross valuable contouring lines. Avoidance of these areas could involve a significant route change and deviation from the desired contour level. Despite this, it would be ideal if damage to seepage zone vegetation could be minimised, often located within shallow gulleys, re-entrant features or associated with ground level rock outcrops that cross steep slopes.


  • On hillsides, soil movements within dry and wet acid grassland areas can develop well-defined micro-terrace systems, often referred to as sheep walks or trods. These typically follow contours and can provide extremely useful running lines. Grassland vegetation at the edge of these micro-terraces is often friable and easily broken off. Care should be taken when using these features for contouring to avoid running on the edge of these terraces to minimise grassland damage.


  • Boulder field habitats are present on the summits of the highest hills within the event area that are potentially vulnerable to disturbance. Boulder fields on the highest hills support fragile montane grass-heath plant communities of high nature conservation value. Existing paths through these areas should be used where possible to avoid disturbance of these communities. Blocky scree often supports specialised plant communities that utilise the microclimate of sheltered spaces within the scree. Sections of Marmot Dark Mountains courses that cross these features should use existing paths where possible and should always minimise disturbance of scree blocks.


  • Specialised rock ledge plant communities are present at a number of locations within the event area. If Marmot Dark Mountains participants need to negotiate low rock outcrops great care should be taken to minimise disturbance of ledge vegetation.


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Expect remote and wild terrain ©Steve Ashworth