Above the stunning landscape of Glenfeshie lies the “Great Moss”, the Mòine Mhór, forming a gentle, rolling plateau of peatlands at an altitude of between 900 and 1000 metres. This makes it probably the largest extent of high-altitude blanket mire in Britain, set amongst snow-bed grassland and associated montane sedge, lichen and bryophyte communities.
Dr Olivia Bragg from Dundee University took me up to this special bog in a 4x4 open buggy, courtesy of Glenfeshie Estate. This was to see some of the hi-tech monitoring equipment that is in place on the bog and to discuss possible restoration options.
The Cairngorms is the largest area of near-continuous high ground in the UK, with many summits exceeding 1000m altitude, and so the vegetation here has to endure the most extreme climate in the UK. It is therefore surprising to find such a huge expanse of peat at this altitude.
The Mòine Mhór is primarily composed of the NVC sub-community M19c blanket mire (Vaccinium-Hylocomium) and heather (Calluna vulgaris) is largely absent. Cloudberry, crowberry (and its montane sub-species Hermaphroditum) and Sphagnum fuscum are common along with other montane species. Surrounding the bog is Racomitrium lanuginosum heaths and Nardus stricta-Carex bigelowii grass-heath (the latter is a sub-montane grassland community associated with late snowbeds: a very common feature at this altitude).
The peatlands of the Mòine Mhór are heavily eroded, with vast expanses of bare peat, criss-crossed with numerous erosion channels. The peat is up to 1.4m deep in places, though it may have been deeper in the past before it became eroded. Until very recently, red deer numbers were very high in this area (well over 30 deer per square kilometre), and the deer congregated on the plateau in high numbers. The effects over 150 years of trampling, grazing and lying on the peatlands of the Mòine Mhór have led to the rapid loss of peat.
Water and wind action is severe in this high altitude climate, with high rainfall and flash floods a regular feature as well as hurricane force winds. In addition, the bog is covered with snow for at least six months of the year, with freeze/thaw action common resulting in water running under the snow across the peat.
Since 2006 the management of Glenfeshie Estate has changed significantly, with the emphasis on nature conservation and “re-wilding”. Red deer numbers have been reduced significantly, and are now below two per km2 – an achievement the Estate are to be complimented for. Given the current state of the Mòine Mhór, and its climatic position, it is not clear if the bog can recover without intervention. Work by Dundee and Southampton Universities is trying to provide some answers.
Due to the difficulty in accessing the site and unpredictability of the weather, remote monitoring equipment was installed on the Mòine Mhór, connected by a number of transmitters down to the Estate Office and directly to researchers. Data collection is specifically targeting the temperature of the bare peat on the surface and up to depths of 40cm. Data on air temperature, solar radiation, rainfall, humidity and air pressure is also collected and there is a camera on the site.
The data indicates that the temperature under the bare peat surfaces drops below freezing on a regular basis. This has implications for plants attempting to colonise the hostile bare peat environment.
Work is also on-going looking at the carbon content of water running into the tributaries of the River Feshie. Data was also collected on 279 quadrats recording peat depth, vegetation cover and species composition (if present) across the Mòine Mhór: 22% of quadrats were bare peat.
The data being collected on the Mòine Mhór is all helping to build up a picture of the current status of the bog and the impact of the climate. These data sets will help inform the next steps to be taken to attempt to restore this bog. The key issue appears to be slowing and re-distributing the water flow across the site and thus raise the water table and limit the damaging flood events.
Stephen Corcoran, Land Management Adviser
Cairngorms National Park Authority
