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Last Updated: Saturday, 1 September 2007, 20:17 GMT 21:17 UK
UK peatlands face future stress
Gulley on bog. Image: National Trust
Special dams can keep bogs wet and prevent erosion
Severe erosion and climate change could result in a vast volume of carbon from the UK's peatlands being released into the atmosphere, scientists have warned.

Hotter summers and wetter winters could result in the habitat, described as the "most severely eroded in the world", becoming even less stable, they said.

But if areas were conserved properly, they could actually help the UK reduce emissions, the paper's authors added.

The study was presented at the Royal Geographical Society's annual meeting.

Climate stress

The UK scientists, from the universities of Manchester and Durham, said the bogs and peatlands of northern Britain stored more than 1.5 billion tonnes of carbon.

"Peatlands are areas where there is a high water table, and because of this you get low oxygen conditions within the saturated area that prevents organic materials from breaking down," explained Martin Evans, the paper's lead author.

"If you take the current rate of carbon loss as a result of badly eroded areas and apply this across the whole of the UK's peatlands then you lose about 1.5 million tonnes of carbon each year - that's the worst-case scenario."

If you restore and manage peatlands, you not only avoid losing stored carbon but you actually add to that store
Dr Martin Evans, University of Manchester

Climate projections forecast the UK experiencing warmer summers and stormier, wetter winters.

Dr Evans said the shift in climatic conditions could lead to higher rates of erosion on the landscapes.

"Erosion is caused by things that stress the vegetation layer, which might be pollution or grazing, but it is also climate dryness in particular.

"On the other side of the climate coin is more intense rainfall, which also means that there is more erosive power."

He said these factors could lead to a substantial volume of carbon dioxide being released from the bogs into the atmosphere.

Tale of two landscapes

To understand the impact of erosion on peatlands' ability to store carbon, the team selected two sites - one in the northern Pennines, and the other in the southern reaches of the uplands.

Map showing location of research sites (Image: BBC)

The northern location, Rough Sike, is in the Moorhouse Nature Reserve, one of the UK's most studied moorlands.

The southern Pennine site, Upper North Grain, was situated in an area that was among the nation's most degraded.

"They are almost like the miners' canary," Dr Evans suggested. "If that degree of erosion where to repeated across Britain's peatlands then we would have a problem."

The team found that the study area at Rough Sike had undergone extensive natural revegetation on gully slopes and beds, limiting the amount of carbon particles being washed away.

This was in contrast to their observations at Upper North Grain: "Sediment is eroded from exposed peat faces on gully walls and rapidly evacuated from the catchment (area)," they wrote.

Dr Evans said this highlighted the need for effective land management.

"If you restore and manage peatlands, you not only avoid losing stored carbon but you actually add to that store," he said.

"Revegetated gullies seem to be locking up carbon more quickly than some intact areas of the bogs.

"The gullies are very wet so plants grow very nicely; they photosynthesise and store carbon dioxide taken out of the atmosphere and store it in plant tissue, which when it dies becomes incorporated in the peat."

He said that there were a number of schemes that looked promising.

The National Trust has been installing a series of small dams in gullies. The dams create small pools that allow peat sediment to settle and grasses and mosses to recover.

The scientists hoped their research, published in the Geomorphology journal, would help identify areas that were at risk from increased rates of erosion and needed protecting.

'Preserve peat bogs' for climate
28 Mar 07 |  Science/Nature
Reading peat's carbon contribution
28 Mar 07 |  Science/Nature
Action urged to save peat bogs
02 Feb 00 |  Sci/Tech

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