Upland peatlands

The first in a series of posts covering the 'peatlands' in the uplands of the UK.

Peatland in the Brecon Beacons National Park

A generally accepted definition of what constitutes an upland in the UK is the uncultivated land above 250m - 400m in England and Wales, whilst in Northern Ireland and Scotland upland environments can occur at lower elevations. A relief map of the UK is one way of visually representing the distribution of uplands.

Relief map of the UK
By Captain Blood - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=930331

A case could also be made for visually representing uplands by climatic criteria.

http://www.metoffice.gov.uk/public/weather/climate

Wind

http://www.metoffice.gov.uk/public/weather/climate

Rainfall

http://www.metoffice.gov.uk/public/weather/climate

Days of rain

http://www.metoffice.gov.uk/public/weather/climate

Mean Maximum Temperature

http://www.metoffice.gov.uk/public/weather/climate

Mean Minimum Temperatures

http://www.metoffice.gov.uk/public/weather/climate

So on average the UK upland climate is cool, windy and often wet. The rain falls onto ground underlain by predominantly impermeable bedrock lithologies and that causes at least seasonal waterlogging of the overlying soil layer. Water saturated soils create anaerobic conditions and low temperatures reduce biological activity slowing down the rate of organic material decomposition. Once a threshold is passed for low temperature/months of soil waterlogging, organic material starts to accumulate in soil.

View uphill of an exposure of blanket peat and minerogenic surface from fluvial erosion on a moderate hill slope ~ Mynydd Du, Brecon beacons National Park.

Unsurprisingly the uplands also reveal their presence on a soil carbon map.

Ostle, Nicholas & Levy, Peter & D. Evans, C & Smith, P. (2009). UK land use and soil carbon sequestration. Land Use Policy 26:S274-S283. Land Use Policy. 26. . 10.1016/j.landusepol.2009.08.006.

Comparing the organic carbon content of the UK upland soils to European soils highlights their significance and explains why so many walkers in southern Europe wear fabric walking boots.

There are numerous descriptions of what constitutes a peatland in press - varying minimum depths of peat, satisfying a varying minimum criteria of % carbon content covering a minimum area of land. The International Union for Conservation of Nature, UK Committee have taken a pragmatic approach and define it simply as:

Peatlands are areas of land with a naturally accumulated layer of peat. These are formed under waterlogged conditions from carbon rich, dead and decaying plant material. 

The next post will concentrate on the vegetation and habitats that cover upland peatlands.

Rannoch Moor