Environmental and Socio-economic Benefits of Peatland Restoration

This site compiles evidence on the environmental and socio-economic benefits of peatland restoration carried out by water@leeds scientists.

There is a cost to delayed action

In research focused on Scotland, Glenk and Martin-Ortega (2018) investigated the value that people place on the benefits of peatland restoration, such as carbon capture, habitat provision and regulation of water quality. They found that restoring 20% of Scottish peatland would result in economic benefits estimated at between £79.6 and £287.6 million over a period of 15 years (these are net benefits, i.e. after taking restoration costs into account).

A follow on study concluded that restoration would provide £191 million of economic benefits annually for the country if it took place by 2027, rather than delayed to 2039–2050 (Glenk, Faccioli, Martin-Ortega et al. 2021). This means that delaying restoration of peatland would lead to substantial loss of economic benefits to society.

Restoring peat bogs will reduce the risk of flooding

In 2008 Holden et al. published research that showed how water running over Sphagnum on blanket peatlands moved much more slowly (often ten times slower) than water running through sedges or over bare peat. This spawned a new body of research which has shown how revegetation of peat, particularly by a dense Sphagnum cover, can slow the flow of water during storm events to reduce the flood peak downstream (Grayson et al. 2010; Shuttleworth et al. 2019). These effects hold (and can be proportionally greater) even for the very largest storm events (Gao et al. 2018). The research shows the importance of restoring strips of peatland either side of watercourses, and other gently sloping parts of the catchment to maximise flood reduction benefits.

Restoring peat bogs will reduce wildfires impacts

Those in favour of managed burning of UK moorlands, including peatlands, suggest it is an important tool in reducing the fuel load of the above-ground parts of the heather plants, thereby lowering the risk of damaging wildfire (e.g., Marrs et al., 2019). In a short piece in Nature Geoscience Baird et al. (2019) challenge this argument, and note that re-wetting is a far better tool. Heather does not grow well in water-logged conditions, so a wet peatland has a lower fuel load; the heather does not need managing, it does not need burning. The wetter conditions in themselves also act to reduce the chance and severity of wildfire. Abundant heather is an indicator that a peatland is too dry. Rather than continuing with a cycle of burning to manage the heather, it is better to increase the wetness of the peatland.

Restored peatland can increase biodiversity

An estimated 1 million ponds have been lost in the UK over the last 3-4 decades; in peatlands though, rewetting provides large-scale pond creation opportunities which benefits aquatic species. Recent drain-blocking initiatives to rewet damaged peatlands have created hundreds of thousands of new pools. Research has found that these are being colonised readily by a diverse assemblage of aquatic organisms, similar to previously undisturbed peatland sites (Carter et al. 2015; Brown et al. 2016; Swindles et al. 2016). This is highly beneficial for upland biodiversity and should improve resistance and resilience of upland wildlife to future disturbances and environmental change. In addition to preventing erosion, rewetting peat and increasing carbon sequestration, these findings highlight a further positive effect of peat restoration for upland ecosystems in terms of increased biodiversity.

Sediment release from bare peat strongly influences peatland stream ecosystems (Aspray et al 2017; Brown et al 2019) affecting both their biodiversity and functioning. Targeted restoration work that aims to achieve a dense Sphagnum layer will reduce sediment and deliver maximum downstream benefits for river habitats and flood risk, while simultaneously adding resilience to the peatland ecosystems in the face of climate change, drought and wildfire.

New research has cast doubt on carbon accumulation under managed burning

Previous claims that peatlands continue to build up under a managed burning regime - that is that more organic matter and carbon (C) is added via plant growth than is lost by decay - are based on two studies: Heinemeyer et al. (2018) and Marrs et al. (2019), which use a metric called aCAR (the apparent rate of carbon accumulation) calculated from peat-core data. Two new papers (Young et al., 2019; Young et al., 2021) clearly show that it is not possible to say using aCAR whether a burning regime leads to a net C loss or net gain; other methods are needed. Studies that use aCAR to infer effects of past climate or management on peatland carbon balance are unreliable and should not be used to inform policy.

Lowland agricultural peatlands also need urgent action

Approximately 90% of the UK’s lowland peatlands have been drained for cultivation. This exposes previously waterlogged organic matter to sustained decomposition which produces carbon dioxide that is lost to the atmosphere. Thus, agricultural peatlands are the largest land use source of carbon emissions in the UK and crops grown on peat have among the highest production intensities (GHG emissions per crop calorie) in the world. Recent research by Evans et al. (2021) has shown that bringing the water table to within 30 centimetres of the ground surface greatly reduces decomposition, reducing warming by the equivalent of at least 3 tonnes of carbon dioxide per hectare per year. This would still allow productive use of the land for agriculture. Policies need to be urgently promoting agricultural practices that mitigate greenhouse gas emissions from lowland peatlands, like raising water levels.

Evidence provided by water@leeds: Prof. Julia Martin-Ortega, Prof. Joseph Holden, Prof. Andrew Baird, Prof. Pippa Chapman, Prof. Lee Brown, Dr. Paul Morris, Dr. Dylan Young, Dr. Richard Grayson (University of Leeds) and Dr. Klaus Glenk (SRUC), on research funded mainly by the UK’s Natural Environment Research Council , the Scottish Government and the Department for Environment, Food and Rural Affairs. This briefing was supported by Policy Leeds.

References

Aspray, K. L., Holden, J., Ledger, M. E., Mainstone, C. & Brown, L. E. (2017) Organic sediment pulses impact rivers across multiple levels of ecological organisation. Ecohydrology https://doi.org/10.1002/eco.1855

Baird, A.J., Evans, C.D., Mills, R., Morris, P.J., Page, S.E., Peacock, M., Reed, M., Robroek, B.J.M., Stoneman, R., Swindles, G.T., Thom, T., Waddington, J.M., Young, D.M. (2019) Validity of managing peatlands with fire. Nature Geoscience, 12, 884–885. https://doi.org/10.1038/s41561-019-0477-5.

Brown, L. E. et al. (2019) Sediment deposits from eroding peatlands alter headwater river invertebrate biodiversity. Global Change Biology 25, 602-619

Brown, L.E.  Sorain J. Ramchunder, Jeannie M. Beadle, Joseph Holden. (2016) Macroinvertebrate community assembly in pools created during peatland restoration. Science of the Total Environment. 569–570, p. 361-372. https://doi.org/10.1016/j.scitotenv.2016.06.169

Carter, Christopher F.; Beadle, Jeannie M.; John, David M.; Brown, Lee E. (2015) New observations on Saturnella saturnus (Steinecke) Fott: the first British record of a little-known enigmatic 'green' alga. Algological Studies Volume 149 (2015), p. 61 – 77. https://doi.org/10.1127/algol_stud/2015/0247

Evans, C.D.,  M. Peacock, A. J. Baird, R. R. E. Artz, A. Burden, N. Callaghan, P. J. Chapman, H. M. Cooper, M. Coyle, E. Craig, A. Cumming, S. Dixon, V. Gauci, R. P. Grayson, C. Helfter, C. M. Heppell, J. Holden, D. L. Jones, J. Kaduk, P. Levy, R. Matthews, N. P. McNamara, T. Misselbrook, S. Oakley, S. E. Page, M. Rayment, L. M. Ridley, K. M. Stanley, J. L. Williamson, F. Worrall & R. Morrison (2021). Overriding water table control on managed peatland greenhouse gas emissions. Nature volume 593, pp. 548–552: https://www.nature.com/articles/s41586-021-03523-1

Gao, J., Kirkby, M. & Holden, J. (2018) The effect of interactions between rainfall patterns and land-cover change on flood peaks in upland peatlands. Journal of Hydrology 567, 549-559

Glenk K, Faccioli M, Martin-Ortega J, Schulze C, Potts J. (2021)[1] The opportunity cost of delaying climate action: peatland restoration and resilience to climate change. Global Environmental Change: https://www.sciencedirect.com/science/article/pii/S0959378021001023

Glenk K, Martin-Ortega J. (2018) The economics of peatland restoration. Journal of Environmental Economics and Policy. 7(4), pp. 345-362: https://www.tandfonline.com/doi/full/10.1080/21606544.2018.1434562

Grayson, R., Holden, J. & Rose, R. (2010) Long-term change in storm hydrographs in response to peatland vegetation change. Journal of Hydrology 389, 336-343

Heinemeyer, A., Asena, Q., Burn, W.L., Jones, A.L. (2018) Peatland carbon stocks and burn history: Blanket bog peat core evidence highlights charcoal impacts on peat physical properties and long-term carbon storage. Geo: Geography and Environment, 5, e00063. https://doi.org/10.1002/geo2.63

Holden, J. et al. (2008) Factors affecting overland flow velocity in peatlands. Water Resources Research 44, W06415. https://doi.org/10.1029/2007WR006052

Marrs, R.H., Marsland, E.L., Lingard, R., Appleby, P.G., Piliposyan, G.T., Rose, R.J., O’Reilly, J., Milligan, G., Allen, K.A., Alday, J.G., Santana, V., Lee, H., Halsall, K., Chiverrell, R.C. (2019) Experimental evidence for sustained carbon sequestration in fire-managed, peat moorlands. Nature Geoscience, 12, 108 https://doi.org/10.1038/s41561-018-0266-6

Shuttleworth, E. L. et al. (2019) Restoration of blanket peat moorland delays stormflow from hillslopes and reduces peak discharge. Journal of Hydrology X 2, 100006

Swindles et al. (2016) Evaluating the use of dominant microbial consumers (testate amoebae) as indicators of blanket peatland restoration link. Ecological Indicators. Vol 69, Pages 318-330 https://doi.org/10.1016/j.ecolind.2016.04.038

Young, D.M., Baird, A.J., Charman, D.J., Evans, C.D., Gallego-Sala, A.V., Gill, P.J., Hughes, P.D.M., Morris, P.J., Swindles, G.T. (2019) Misinterpreting carbon accumulation rates in records from near-surface peat. Scientific Reports, 9, 17939. https://doi.org/10.1038/s41598-019-53879-8

Young, D.M., Baird, A.J., Gallego-Sala, A.V., Loisel, J. (2021) A cautionary tale about using the apparent carbon accumulation rate (aCAR) obtained from peat cores. Scientific Reports, 11, 9547. https://doi.org/10.1038/s41598-021-88766-8

[1] Information from Glenk et al. 2018 & 2021 studies can also be found in this press release: https://www.leeds.ac.uk/news-environment/news/article/4916/act-now-for-economic-benefits-from-peatland-restoration