How peatland restoration at Cuilcagh is helping to tackle climate change

This winter we worked with local landowners on Cuilcagh Mountain Special Area of Conservation (SAC) to restore precious blanket bog habitat, through funding from the EU Interreg CANN project. Landowners were trained in specialist restoration techniques and worked to stabilise and revegetate 17ha of eroding peat. This type of restoration is vital, not only to protect our native wildlife but also in the fight against climate change.

Benefits of healthy blanket bogs

Blanket bogs are one of the world’s rarest habitats. The UK and Ireland boast 20% of the world’s total blanket bog area, with almost 10% of Northern Ireland covered in this globally scarce habitat. These landscapes are a refuge for some of our most iconic and endangered wildlife, like Golden Plover, Hen Harrier and Irish Hare. As well as underpinning NI’s hill farming industry, they provide us with drinking water and help alleviate downstream flooding.

Formed over millennia, blanket bogs are also vast carbon stores. As peatland vegetation grows it captures CO2 from the atmosphere. This carbon is then trapped as peat, which forms as a result of acidic, waterlogged conditions preventing the dead plant material fully decomposing. In the UK, peatlands store 20 times more carbon than all the forests combined!

Carbon stores vs carbon emitters

However, all these benefits are lost when blanket bogs are degraded. Decades of mismanagement through unsustainable grazing, drainage, burning and afforestation, as well as the wider impacts of pollution and climate change, have damaged these important landscapes.  Only 20% of the UK’s blanket bogs are in a natural or semi-natural state, with the UK’s peatlands now classed as net carbon emitters.

Erosion gullies, like those being restored on Cuilcagh Mountain, occur when this damage leads to the loss of surface vegetation. This exposes the bare peat below which is easily eroded through wind and rain. Over the years this erosion forms a complex maze of steep sided gully channels and isolated peat islands (haggs), which can be several metres deep and wide.

Bare peat is bad news for everyone. It isn’t useful for grazing, wildlife cannot thrive there, it releases carbon into our atmosphere and washes into our water courses, negatively impacting drinking water supply and aquatic habitats. Up to 3cm of peat can be lost a year, with severely eroding areas producing over 30 tonnes of CO2 - equivalents per hectare per year!

Restoring Cuilcagh

Following a restoration plan devised by RPS hydrologists, alongside the support and knowledge of landowners, the first step to recovery was to reprofile 2.5km of bare gully edges, using low ground pressure excavators on bog mats. The steep edges were graded to 30-35 degree slopes, then covered with turfs of borrowed vegetation. These gentler slopes allow for vegetation to recolonise and prevent continued erosion.

The flow of water in bare gully bases, and the seasonal freeze/thaw and drying out of exposed peat, mean that conditions are too hostile for vegetation to establish and grow. Coir rolls, made from the outer husk of coconuts (a by-product of the coconut industry), were placed across the bare peat to intercept the erosive flowing water. These fibres trap the peat sediment, stopping it washing off the mountain, but allow water to seep through slowly enough to rewet the area. This creates the conditions needed to allow natural bog plants to re-establish. The worst affected bare areas will have stock exclusion fencing, to give vegetation a chance to establish.

Carbon in Balance – Coconuts and Helicopters

Despite the carbon benefits of restoring peatlands being well known, using helicopters to transport materials to site, and even shipping material like coir, may lead some to ask if this tips the carbon balance.

Carrying many tons of coir rolls and fencing materials up the mountain, either using machinery or human power, would cause significant damage to the sensitive habitats through repeated tracking over very long distances. Using the helicopter meant we could reach the remote areas of the site without causing any damage to the important habitat in the process, and all materials were transported in less than one day.

When creating the restoration plan, RPS hydrologists looked to proven techniques from across the UK, where use of coir rolls has been standard practice for peatland restoration for more than 10 years.

The rolls are excellent at trapping peat and coir’s high lignin content means it takes up to 10 years to rot away, allowing enough time for the restabilising plants to root and start protecting the underlying peat from erosion.

Moors for the Future Partnership regularly use helicopters to transport materials for peatland restoration projects, including coir. Their carbon audits indicate that the restoration outcomes far outweigh the carbon emissions. They calculate that one year following revegetation, the magnitude of the avoided carbon losses from bare peat will be 37 times that of the emissions produced through undertaking the work, including use of helicopters.  This is also before factoring in all the associated (non-carbon linked) benefits of gully restoration for water quality, flood management and native wildlife.

Coir in place with pooled water

Innovative and Local Alternatives

However, we are always looking to improve on the standard practice in peatland restoration and to this end have trialled a light-weight, novel sediment trap technique in the area, with permission from NIEA. If successful, these solutions could replace materials like coir in the future and reduce the associated carbon costs of transportation to site. We are also planning to explore the feasibility and effectiveness of potential alternatives for gully blocking, such as locally-sourced heather bales and wool. We have used local sheep’s wool and peat itself in other types of restoration work on Cuilcagh and are monitoring the results. 

When we trial alternatives, we must bear in mind that Cuilcagh is an internationally important, protected site and there needs to be a balance between trying novel techniques (with a possibility of failure) and the immediate need for effective restoration using established techniques.

We must take care when using local materials such as heather bales, that our removal does not damage one area to restore another, or that the materials used don’t introduce invasive plant seeds or pests to the SAC, such as conifers and heather beetle. The longevity of materials is also important, with the idea of locally grown straw being abandoned as it simply does not last long enough to act as an effective sediment trap.

We have secured funding to do a carbon audit of Ulster Wildlife’s operations, which will include this gully restoration project. We expect the results to illustrate a carbon positive approach, and the effectiveness of this valuable work in restoring this rare and important habitat on Cuilcagh.