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Peatland restoration: Dr. Tim Thom, Yorkshire wildlife trust.
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Global Distribution of Peatlands
Approximately 4 million km2
175 countries from tropics to poles
3% of the world’s land area
UK Distribution of Peatlands
Peatlands occur in a number of different forms in the UK: fens, wet woodland and bogs
92% of the peatland in the UK occurs as blanket and raised bogs
The UK has about 13% of the world’s blanket bog
Carbon storage & sink
Peatlands cover just 3% of the world’s land surface but store more than 30% of the total global soil carbon
A loss of just 1.6% of the global peat store equates to the total annual global anthropogenic greenhouse gas emissions
In the UK peatlands store 3 200 million tonnes of carbon, 20 times than that of UK forests
A loss of just 5% of the UK peat store equates to the total annual UK anthropogenic greenhouse gas emissions
Semi-natural, intact bogs may remove 30-70 tonnes of carbon per km2 per year
Biodiversity
Largest area of semi-natural habitat in the UK containing 16 NVC plant communities
Supports a unique, rare and threatened range of specialised species adapted to waterlogged, nutrient-poor conditions such as sundews and Sphagnum
Internationally important bird assemblages such as golden plover, dunlin, merlin & hen harrier (designated as SPA)
One of the most ancient and unique habitats in Europe dating back thousands of years (designated as SAC)
History
Preserved pollen and partially decomposed plant remains enables reconstruction of vegetation and land management history.
Record of past atmospheric pollution levels
Record of past events – eg volcanic eruptions
Archaeological artefacts
Economy
As major tourist attractions peatland bring the tourist pound into remote areas supporting accommodation providers and local communites
Management of peatlands for grouse (or deer stalking in Scotland) provides employment opportunities for keepers and other sporting managers
Peatlands are an integral part of the extensive sheep farming systems of the UK uplands
In some areas of the UK peat is still exploited as a fuel source
Current state of peatlandsLess than 20% of blanket bog in UK is in a natural or near-natural condition
Majority of UK peatlands are no longer peat forming
16% severely eroded, 10% afforested, 11% affected by past peat-cutting, 40% modified or destroyed by conversion to agriculture
Now emitting 3.7million tonnes of CO2 equivalents per year > average annual emissions of Leeds, Edinburgh and Cardiff.
Only 58% of internationally designated blanket bog is in favourable condition. Of the rest only 15% is recovering
Over last 30 years amount of dissolved organic carbon (brown colour) in water draining peatlands has doubled which has to be taken out by water companies
Key damaging driversLarge areas drained with ditches (grips) through agricultural subsidies. No longer funded but still flowing and eroding
10% of UK peatlands afforested. Generally requires drainage, cultivation and fertilisation which causes peat to crack, shrink and oxidise
Heavy grazing changes the vegetation converting from specialists to grass dominated peatlands which begin to erode and stop peat forming.
Fire. Wildfire and poorly-managed burns on grouse moors damages Sphagnum and leads to conversion to heather and grasses. Dessicated peatlands are drier and more prone to fire – a vicious circle
Partnership funded by:
Yorkshire Wildlife Trust
Yorkshire Dales NPA
North York Moors NPA
Environment Agency
Natural England
Yorkshire Water
National Trust
Other Partners:
Yorkshire Dales rivers Trust
Nidderdale AONB
Pennine Prospects
Moorland Association
National Gamekeepers Association
National Farmers Union
Objectives•Restore 35,000 (50%) of peatland by restoring 3401km (45%) of grip/gully and re-vegetating 169ha (50%) of bare peat by March 2017
• Establish long-term sites for research into the benefits of peatland restoration to ecosystem services by March 2013
•To use and promote best practice in all applied restoration techniques
•To raise awareness and promote the multitude of benefits that peatland restoration can provide
Part A – Aerial Photographs
Part B – Rapid Walkover
Category 1b - Blocked grip
Category 3 - Eroding and deeply scoured; >1000mm-1500mm wide; >1000mm-1200mm deep
Category 1f - Flowing grip up to 600mm wide; 650mm deep
Category 4+
Eroding Hags Peat Pans
Micro Erosion Oxidised Peat
Grip blocking
Gully blocking
Majority of larger grips and some gullies can be blocked using timber sediment traps
Gully/hag reprofiling
All gullies but especially larger ones that can’t be blocked are re-profiled and then re-vegetated to remove source of continued erosion
Re-vegetating bare peat
Bare peat needs treating in several ways to get a vegetation cover to establish
pH levels often too low for vegetation (even Sphagnum)
Wind, water and frost heave in exposed areas mean surface is continually mobile so vegetation cannot get a hold
Vulnerable to dessiccation in dry periods
Cut heather brash
Transport brash to site
Spread brash to stabilise surface
Create stable root mat
Spread lime & fertiliser to support growth for 3 yrs
3 yrs on all being well
Establish Sphagnum & other peat formers
Results so farAchievement by December 2011 Quantity
Area of land surveyed 16,542ha (48%)
Area under restoration 3283ha (10%)
Length of grips blocked 334km (13%)
Length of eroding gullies re-vegetated 40km (5%)
Area of bare peat re-vegetated 17ha (10%)
Number of peat dams installed in grips 33,000
Number of timber sediment traps installed in larger grips and gullies
300
Number of peat depth records 20,000
Number of volunteers involved 40
Carbon & climate change
Biodiversity & History
Restore the peat we regain the biodiversity and prevent the loss of the historic record
Water quality
Blocking reduces fine particulate organic matter, suspended solids and bed sediment leading to change back to Ephemeroptera, Plecoptera, Trichoptera from Diptera.
Restoration works!