Important new study on impacts of moorland burning on river catchments

Photo: Donside April 2014 by Peter Cairns
Photo: Donside April 2014 by Peter Cairns06

The EMBER study by the University of Leeds (funded by NERC and Yorkshire Water) has been a five-year study of 10 river catchments – five that have lots of heather burning for driven grouse shooting and five that do not. The study area was the North Pennines.

The British uplands collect and distribute rainwater, sequester carbon in the form of peat and provide the habitats for many important species.  In some areas, land management is dominated by the industry of driven grouse shooting where burning of heather to produce artificially very high densities of Red Grouse for shooting is part of the traditional management regime.

Rotational burning of heather is important for grouse shooting but what does it do for the rest of us?

These are the results of this major study and they indicate, in just about every respect, that burning of heather imposes a cost on the taxpayer and society.

 

  • Heather burning. Photo: Paul Adams via wikimedia commons.
    Heather burning. Photo: Paul Adams via wikimedia commons.

    Prescribed burning on peatlands was shown to have clear effects on peat hydrology, peat chemistry and physical properties, river water chemistry and river biota.

  • Burning reduces the organic matter content of the upper peat layers. The net result is that the peat is less able to retain important particles known as exchangeable cations. In other words, the peat in burned sites is deprived of chemicals which are important for plant growth and for buffering acidic rainfall.
  • Lower concentrations of nutrient elements found in peat soils in burned river basins do not support the idea that burning  enriches the peat with nutrients from ash.
  • Rivers draining burned catchments were characterised by lower calcium concentrations and lower pH relative to rivers draining unburned catchments. Rivers draining burned sites had higher concentrations of silica, manganese, iron and aluminium compared to unburned catchments.
  • There was no difference between burned and unburned catchments in peat nitrogen concentrations or in carbon to nitrogen ratios (high C/N is considered unfavourable to microbial decomposition of peat), and no significant difference in peat soil pH.
  • Water-table depth is very important in peatlands for maintaining their stability and function as a carbon store. Water tables were found to be significantly deeper for burnedcatchments than for unburned ones. Deeper water tables would suggest a greater scope for degradation of the peat and loss of carbon to the atmosphere.
  • Heather burning. Photo: Paul Adams via wikimedia commons.
    Heather burning. Photo: Paul Adams via wikimedia commons.

    Sphagnum is an important peat-forming species. Changes in the hydrological properties of the peat after fire make the peat less conducive to moss growth.

  • River flow in catchments where burning has taken place appears to be slightly more prone to higher flow peaks during heavy rain. However, this was not a conclusive finding.
  • Burning vegetation alters the natural peat hydrology in the upper layers of the peat affecting the balance of where water flow occurs. Recovery of many hydrological properties appears to be possible if a site is left unburned over many years.
  • Prescribed peatland vegetation burning leads to significant increases in mean and maximum near-surface soil temperatures in the years following burning as well as lower minima (and thus wider thermal variability).
  • Thermal regimes appear to recover as vegetation regrows. This recovery was also seen in soil hydrology data from burned plots of different ages.
  • Heather burning. Photo: Paul Adams via wikimedia commons.
    Heather burning. Photo: Paul Adams via wikimedia commons.

    Macroinvertebrates play a vital role in aquatic food webs by feeding on algae, microbes and detritus at the base of food chains before they themselves are consumed by birds, fish and amphibians. The research found that river macroinvertebrate diversity was reduced in burned sites.

  • Particulate organic matter (predominantly peat) deposits were increased up to four-fold in the bed sediments of burned rivers compared to unburned rivers.
  • In burned sites, river macroinvertebrate populations were dominated by groups that are commonly found in higher abundance in disturbed river systems, such as non-biting midge larvae (Chironomidae) and burrowing stonefly larvae (Nemouridae).
  • Increases in the abundance of disturbance-tolerant taxa counteract declines and/or losses amongst some groups (e.g. mayflies) which are typically sensitive to reduced pH, increased aluminium and deposition of fine sediments. These changes show that burning increases the effect of biological stressors compared to unburned rivers.

In other words, the researchers say that heather burning puts particulate matter into your rivers, makes rivers more acidic, reduces the numbers of many invertebrates (some of which are replaced by ones characteristic of knackered rivers), reduces the soil quality and organic matter of the peat, reduces the water table and makes carbon loss to the atmosphere more likely.

Farmers simply wouldn’t be allowed to behave in this way.

A day’s driven grouse shooting has a cost of maybe £45,000 for a group of six guns.  The environmental damage caused by heather burning is picked up in increased water bills, increased risk of flooding and increased climate change impacts by all of society.

Any policy-maker or politician, unless they shoot grouse (as have several recent Defra ministers, of course), should see that the public costs of grouse shooting vastly outweigh the private benefits.

The sport of the few should not be allowed to degrade the environment of the many.  Sign here to ban driven grouse shooting.

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24 Replies to “Important new study on impacts of moorland burning on river catchments”

  1. Confirms what many of us have believed for a long time, heather burning may be great for grouse shoot management but it has pretty poor knock on effects and should be much more rigorously controlled or banned altogether.

    1. The positive contribution that this report could make to improved land management practices is reduced by the political statements that are made in conjunction with the findings. The business of grouse shooting provides much needed economic turnover in rural communities. Salaries for hard working locals, local accommodation for beaters, catering contracts for local businesses, maintenance of vehicles by local agricultural engineers to name but a few benefits. Practices can change, alternatives to burning no doubt can be found and best practice discussed and improved. I support communication without politics, who agrees?

      1. Christian – thank you for your comment. Welcome!

        That’s a rather political suggestion.

        ‘Alternatives to burning no doubt can be found’? Oh yes? It’s a tradition you know…

  2. Now, the ban on stubble burning didn’t bring about the end of the world…. It’s certainly time for a ban on burning on blanket peat.

  3. With all the hype on climate change & species, this study shows that Amanda Anderson & all the Grouse Estates are talking a load if crap to justify Driven Grouse Shooting. The natural balance needs to be restored to our moorlands & people need to stop destroying the habitats of wildlife. They survived before we started messing around with it, so leave it be and let nature take it’s course. Now is the time to protect what we have left, ban driven grouse shooting, once & for all.

  4. Has there been any comparative study of Grouse breeding success on managed and unmanaged moorland Mark?

    1. Philip – it would be amazing if Red Grouse didn’t do much better on areas managed almost solely for their benefit, wouldn’t it? Driven shooting needs that massive productivity to remain financially profitable – although environmentally it has so many aspects on the ‘loss’ side of the balance.

      1. Indeed Mark. I just wondered how great the difference is and whether some burning is a good thing just maybe not on the intensive scale employed on shooting estates.

  5. I wonder if Liz Truss, Environment Secretary, was referring to the results of this study when she said in her speech to the Conservative Party Conference:
    “I am determined to press ahead restoring habitats,
    ….cleaning rivers……………”

    Perhaps not………………………………………………..

  6. The Hawk and Owl Trust had an accidental fire on its Fylingdales Moor (ex grouse moor) a few years ago. I don’t know whether before and after studies were done but will ask. There are certainly red grouse present

  7. This is very interesting, and I cant wait to dig into it. Re grouse productivity, I suspect there will be surprising results there also. In years following natural crashes in non-managed grouse, including willow grouse and black grouse etc, productivity can be very high and survival to fledging very high as the cover is better against the few predators remaining after the crash. I can actually see the tide turning much more strongly against traditional grouse management now, and for all the right reasons, I just hope we don’t end up with more sheep. Yesterday I sent an email to the ilkley moor stakeholders to suggest they seek a radical solution instead of walking vs driven grouse and aim to create a wild moorland where people from all backgrounds can use the area for all their interests, from walking , to birding , to cycling to shrooming to an odd walked up shoot managed by public permits and quota (like an LNR permit scheme). Would be nice to work together :0)

  8. The elephant is leaving the room. The peat is going!

    To see what I mean Google Images for Holme Fen Post to see a lamp post driven full height into the organic fen soil in Victorian times now standing proud and full height.
    Your quotes from the report:
    “Deeper water tables would suggest a greater scope for degradation of the peat and loss of carbon to the atmosphere.”
    “Particulate organic matter (predominantly peat) deposits were increased up to four-fold in the bed sediments of burned rivers compared to unburned rivers.”

    The report you quote, I assume, made no estimate of the loss of peat to oxidation. This is the curse of disturbing soils and drying them out everywhere in the world.

    Horticulturalists are not allowed to use peat but this is just as bad over the long term. viz the lamp post.

  9. If you want a laugh, read Andrew Gilruth’s blog on the report on the GWCT website – Im sensing some panic here! http://gamewildlife.blogspot.co.uk/2014/10/is-it-time-to-ban-heather-burning.html

    What Andrew fails to point out in his justification and ‘mitigation’ of burning is that the Heather and Grass burning code has a presumption against burning of sensitive features such as peat bog and wet heathland – the exact thing the Leeds report says is stupid to do for a host of reasons. He’s already talking about how to mitigate the impacts highlighted by the report – its simple, don’t burn deep peat soils or lets just ban driven grouse shooting as the ‘industry’/hobby and its supporters can’t take the issues seriously and adapt to change or regulation.

    Also worth Andrew noting that the RSPB don’t burn on deep peat soils on their Geltsdale reserve so this is in no way a supporting factor to continue the practice in his link to their website. Also what is the percentage of wildfires resulting from ‘controlled’ burns?

    His last sentence on roads and tracks made me chuckle – has he heard of Walshaw or Wemmergill moors?

    1. Gongfarmer – spot on!

      It is also worth pointing out just how feeble and irrelevant Andrew Gilruth’s ploughing analogy is. Unsuprisingly he omits two key points; firstly ploughing is undertaken to produce food which is pretty important to human survival and not as part of a minority recreational activity. Secondly, each year less and less ploughing takes place as farmers are waking up to the considerable economic, agronomic and environmental benefits of conservation/minimum tillage techniques.

      As the GWCT rightly acknowledge on their own website:

      ‘One new type of cultivation is conservation tillage or non-inversion tillage. This is a combination of very shallow cultivation and mulching. This helps to concentrate organic matter in the upper soil layers. It improves soil structure and workability, decreases erosion and leaching, improves drought tolerance and also creates favourable conditions for beneficial predatory invertebrates, micro organisms and earthworms. Weed control is accomplished by good crop rotation and targeted herbicides.

      Nevertheless adopting a soil cultivation system that improves soil structure has many advantages. There is reduced runoff of sediment, pesticide and fertiliser. Less cultivation means less energy consumption, lower carbon dioxide emission and increased carbon sequestration because of more soil organic matter. A richer soil biota improves nutrient recycling and may help combat crop pests and diseases. Non-inversion tillage also leaves seeds and crop litter on the surface as food for wildlife.

      Ploughing is costly in labour, time, energy and machinery. It reduces the soil fauna, exacerbates soil erosion and causes nutrient leaching. Thus adopting an improved cultivation system is at the heart of ICM’

  10. Interesting that neither the blog or the comments make any mention of the importance and rarity of managed heather moorland habitat, and of course upland heath is a BAP priority habitat.

    While cutting is obviously an alternative management, and can be more effective in some situations, it is not always practical, and has disadvantages. For example, it takes much longer to cut than to burn, and land may not always be accessible to be cut. More importantly, cutting does not remove litter at the soil surface, and combined with the debris from the cut this leads to a poor environment for germination and seedling establishment, and impedes new vegetative growth.

    So long as the burn avoids deep peat, and is kept cool, then I don’t have a problem with it as part of the “toolkit” for moorland management, and it is certainly what keeps the heather in a young and vigorous condition.

  11. Is the answer really to ban driven grouse shooting? Or is it really just to ban burning on deep peat? There are alternative heather managements, such as mowing, which are already used at least in part by some of the more forward thinking estates.

    Simply banning shooting will probably lead to lots of illegal shoots and ‘accidental’ fires on moors. Educating estates and actually explaining all the reasons to stop in terms they can understand (including the link between burning drying the peat, there being fewer insects on drier peat and grouse chicks eating predominantly insects in their first few weeks) might be more effective…

    1. Phoebe – educating estates has not proved very effective to date. Thank you for your comment.

  12. I think there’s a big problem with mixing up two issues. Many people jump on this bandwagon not because of concerns about peat but because they don’t like the idea of little birdies being shot. That’s their perogative but it’s a separate issue. The shoots themselves do no harm to the environment.

    It’s difficult therefore to form an objective opinion, as almost everyone writing about the subject has a pre-set agenda either for or against burning, and is selective in the evidence they write about. I don’t have a strong view either way, but what I would say is there is much more to moorland management than heather growth. Remove the economic value of a moor and you remove any willingness to do any management at all. If burns are proven – by proper scientists without agendas – to harm the environment then surely they could be banned or further regulated (they already require licencing) without banning shooting. In any case as someone else pointed out, banning shooting is likely to be very hard to enforce. The fox hunting ban was a massive waste of time & money and has had no significant effect on hunting activities.

  13. I think there’s a big problem with mixing up two issues. Many people jump on this bandwagon not because of concerns about peat but because they don’t like the idea of little birdies being shot. That’s their perogative but it’s a separate issue. The shoots themselves do no harm to the environment.

    It’s difficult therefore to form an objective opinion, as almost everyone writing about the subject has a pre-set agenda either for or against burning, and is selective in the evidence they write about. I don’t have a strong view either way, but what I would say is there is much more to moorland management than heather growth. Remove the economic value of a moor and you remove any willingness to do any management at all. If burns are proven – by proper scientists without agendas – to harm the environment then surely they could be banned or further regulated (they already require licencing) without banning shooting. In any case as someone else pointed out, banning shooting is likely to be very hard to enforce. The fox hunting ban was a massive waste of time & money and has had no significant effect on hunting activities.

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