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Twenty-one

Peatlands

Peatlands: the long-term perspective…

Peatlands

Peatlands: the long-term perspective

Anyone who's ever gone walking in Scotland will have come across peatlands (and probably also got stuck in a bog), but even though “our most iconic views are framed by peatland habitats,” how many people know about the critical role of the peatlands in filtering water and soaking up carbon dioxide emissions? In the fight to mitigate the worst effects of climate change and decades of neglect, scientists in Scotland are studying peatlands from every possible angle – including the airspace above them – to help them to deliver their environmental benefits into the future...

“Much of our peatland is in poor condition and requires suitable management and, in many areas, restoration,” Scotland’s first National Peatland Plan (published in 2015) says at the start. Later on, the report states: “The loss of soil organic matter is one of the key threats to ecosystems, with climate change as a major driver.” The Plan sets out proposals for the “sustainable use, protection, management and restoration” of peatlands, as well as greater public engagement and “a new focus on positive management, supported by evidence and research.” It also seeks to encourage partnerships between private landowners, industry, public bodies and environmental NGOs, plus international collaboration – e.g., to meet the Aichi(1) biodiversity target of restoring at least 15% of degraded ecosystems by 2020.

Faced with these daunting challenges and long-term objectives, scientists in Scotland have been “trying to develop new decision-making tools over the last 10 years” to help the Government, and everyone else with an interest in peatlands, learn about the current state of Scottish peatlands and work out the best ways to manage and restore these important resources.

According to Dr Rebekka Artz of the James Hutton Institute, the key questions are to identify what can be done, and when and where to do it. We know a lot about the general state of the peatlands, but not about current conditions. “Our estimates are based largely on designated sites, which were generally in a better condition to start with,” says Artz, “so we are generally in the dark when it comes to pointing out exactly where the damaged sites are. In particular, we are lacking spatial information to allow us to locate where peatland drainage has taken place and exactly how badly eroded our upland peatlands are.”

In recent years, however, more detailed information has been gathered, not just to diagnose the problems and decide where restoration is a viable option, but also to decide where investment will add the most value. Monitoring current conditions, and assessing the success of restoration projects, has a key role to play, on the ground and from above (planes, drones and satellites), as long as there is funding available over the long term. “Where will restoration be successful in future?” asks Artz. And even if the water table is raised and the vegetation starts to recover, is the project future-proof? How much will it contribute to reducing global greenhouse-gas emissions, thus combatting climate change?

The Chair of the James Hutton Institute’s Board, Professor James Curran, recently said that every £1 spent by the JHI “generates £12 of value-added elsewhere in the economy,” but when it comes to peatlands, the benefits can be much harder to measure. Government funding for peatlands has increased to about £10 million today (including £8 million for restoration through the Peatland Action project this year), but peatlands are a challenge which needs long-term funding to generate visible outcomes. An estimated 35,000 hectares of peatlands have been restored since 1990, largely thanks to recent government initiatives, but an estimated one million hectares has been drained or degraded in the last 100 years, says Artz, based on an analysis of historical data. This not only means that we have lost a vital chunk of ecosystem, but have in the process also released a lot of greenhouse gases stored in the peatlands for thousands of years. And to underline the scale of the challenge, Scotland would need to restore about 115,000 hectares by 2020, to meet the Aichi biodiversity target.

Big data in the big picture

Data are critical in peatlands research as well as in cost-benefit analysis. Data are key to looking at important features such as state of vegetation, as well as much more complicated issues such as carbon emission rates (in degraded sites) or sequestration rates (how much carbon dioxide intact peatlands absorb). This helps to prioritise where work is needed and measure progress, and remote sensing greatly increases the detail, adding to the much more patchy information gathered on the ground. In recent years, the satellite data available has improved dramatically, increasing from a scale of 500 metres per pixel (on NASA’s MODIS satellite) to roughly 10 metres per pixel today on the European Space Agency’s Sentinel satellite. As well as providing much more fine-grain data, remote sensing can also validate data already collected, or help look at areas where access is a problem.

Despite these technological advances, says Artz, remote sensing still has a long way to go. There are well-established methods for looking at the “productivity” of peatland – for example, modelling land surface temperature and vegetation indices of ‘greenness’ – but most of the off-the-shelf data have not been specifically parameterised for peatland biomes. Carbon emissions or sequestration rates are much harder to model at present, in part due to a lack of ground observation to validate models. In addition to identifying where different peatlands (blanket bogs, fenlands and raised bogs) exist, satellite-based modelling could potentially act as “early warning systems” for the ecosystem, helping to predict how the landscape will change in the future.

In Artz’s view, a major challenge for peatland researchers is the need to use long-term satellite data combined with ground observations. Peatlands act as carbon sinks in some years and as sources in others, so it's important to model what happens over the longer term. We know that sequestering carbon dioxide outweighs the methane emissions (more virulent than carbon dioxide) in the average year in intact sites, but to get a more accurate picture, we need long-term data – and that requires long-term investment.

As well as helping to interpret the satellite data, Artz retains an interest in studying the functions of microbiota in peatland ecosystems, including finding out if restoration or regeneration of the surface vegetation will improve the microbial community structure. The link between this work and carbon emissions from peatlands is the function of bacteria and fungi in such environments. They represent the bottleneck in the decomposition of newly-deposited litter, and in intact peatlands at least, decomposition rates are outweighed by the addition of new plant material, allowing peat to form in the long term. This means that the community structure of fungi (but also of other decomposing microbiota) may be a useful indicator of ecosystem health.

Successful restoration of the peatlands needs the right vegetation and the right amount of moisture. You also need to understand the process in detail. “Some projects fail because the wider conditions at the time of the intervention are not right,” Artz explains. “Sometimes, for example, the mulches placed to protect seed material on top of bare peat dry up, blocked drains fail, or the plants don’t take hold. So you need to know what makes that happen and when is the best time to start restoration.”

Some peatlands are simply in a much worse starting condition than others, she says, and we need to ask why a particular area should be restored in the first place. Is it primarily to help reduce emissions? “Doing anything is better than nothing in carbon terms, but the wider restoration benefits may require a longer timeframe than the human eye can easily perceive,” she adds.

Different perspectives

Scotland's peatlands are unique for a number of reasons, says Artz, with “more than its fair share” of peatlands than many other countries with a similar latitude, mainly because of its maritime climate. “There is also intriguing variation on a very small scale,” she explains, with different peatlands thriving in their own microclimates.

Artz’s colleague, plant ecologist Professor Rob Brooker, points out that the peatlands in Scotland are not just important for ecological reasons – for example, by supporting so much wildlife – but also for cultural reasons, providing inspirational landscapes for artists, musicians and writers. “Many of the pictures used for Scottish tourist promotions feature peatlands as part of the image,” he adds, “even though they are not always recognised as peatlands.” Peat is also an important fuel traditionally used by Scotland’s crofting communities, and well-managed peat banks contribute to biodiversity by diversifying the landscape.

“The fact that damaged peatlands can also be responsible for greenhouse gas emissions is also not very well known,” Artz explains. “When peatlands are drained, the ecosystem changes completely, so because we are now more aware of the impact of drainage, it happens very rarely today. But the historic damage has already been done and such sites continue to lose large amounts of carbon that arguably should be fixed instead.”

As well as doing research to support restoration and monitor current conditions, Artz and her colleagues are sometimes brought in to comment on environmental impact assessments – for example, giving their opinion on the potential impact of wind farms which developers propose to build on peatlands. Brooker explains that they provide the underpinning science – and the underpinning data – for these public inquiries; but even with the benefits of satellites and other smart technology, the data are a “moveable feast,” he continues, “because they are the best estimates we can make with the available data,” and these estimates will change with advances in technology. “It’s always possible there may be unexpected changes in our assessments in the future,” he adds, “and one of the scientists’ main contributions is to ask if the assumptions of developers and planners tally with our latest thinking.”

Along with their JHI colleagues, Artz and Brooker also get involved in public outreach. At one recent event, they used several decades’-worth of aerial photographs, including images taken by drones, to illustrate the changes in the peatlands in 3D and over time, to show the visual impact of a well known landscape-scale peatland restoration project. “We got amazing feedback” says Artz. “Sometimes, a fresh pair of eyes can see more than the scientists see, because they are not trained to look for the same kind of things.”

Planning restoration projects can be incredibly complex, even when researchers have identified suitable peatlands. It takes a lot of money to hire the machinery and train the people required, and because there is never enough cash to fund many projects at the same time over several years, lots of “juggling” is needed to allocate funds at the start of the year – and work out potential return on investment.

“There are huge areas of valuable peatlands in Scotland that could be restored, although access to these relatively remote areas is sometimes a problem,” says Artz. “Peatlands are slow-growing environments – fickle and ever-changing. That’s why we’ve got to be in for the long haul, and why we need long-term support.”

Since 2013, Peatland ACTION, led by Scottish Natural Heritage, has started the restoration process on more than 10,000 hectares of degraded peatlands. The Scottish Government provided £8 million to spend on continuing Scotland-wide peatland restoration in 2017–18.

 

(1)The Aichi Plan sets out global targets for biodiversity, and was updated at a meeting in Nagoya, Japan in 2010.

 


Peatlands: Basic Facts

> Peatlands cover more than 20% of Scotland’s land area – a total of two million hectares.

> Scotland's peatlands are also our largest terrestrial carbon store, holding about 1.6 billion tonnes of carbon –  almost 25 times as much carbon as all other plant life in the UK, and the equivalent to over 180 years of greenhouse gas emissions from Scotland at current emission rates.

> Worldwide, peatlands cover about 400 million hectares or 3% of the Earth, most of it in the Northern Hemisphere – storing about one third of the carbon absorbed by the soil.

> Draining, burning and degrading peatlands produces the equivalent of 6–10% of global carbon dioxide emissions caused by burning fossil fuels.

 


The Benefits of Peatlands

To some people, peatlands are wastelands, but conservationists are keen to stress the benefits of one of Scotland's most important natural assets:

> Ecosystem – as well as storing carbon, peatlands also absorb atmospheric pollutants, including sulphur dioxide, nitrogen and heavy metals.

> Natural habitats for birds, plants, fungi, invertebrates and micro-organisms – some very rare.

> Water supply – much of our drinking water comes from peatland areas, which also filter the water.

> Flood management.

> Archaeology – the best preserved human remains are found in peatlands.

> Iconic tourist attractions and inspirational landscapes.

> Fuel.

> Livestock grazing.

> Sport & recreation – deer stalking, grouse shooting, fishing, hill walking, bird-watching.

> Education – outdoor classrooms for history, archaeology and science, etc.

> Whisky production – dependent on peat for drying malted barley.

> Harvestable products – bog myrtle and berries, etc.

 

 

Targets

The principal aim of the National Peatland Plan is to protect, manage and restore peatlands to maintain their natural ecosystem functions, biodiversity and benefits. It also sets out a number of targets for the next 20 years:

By 2020

Improvements in the protection and condition of peatlands – so they’re valued more by everyone. More people using peat-free composts. More private funding for peatland management and restoration, and continued public funding. A network of demonstration sites, a Peatland Code supporting private funding, and peatland management included in national carbon accounting. Protected areas “should be an exemplar of good management in rural Europe.”

By 2030

Peatlands in a healthy state, widely regarded as resilient. Global recognition of the benefits of peatlands to society, reflected in the level of support to manage them as healthy ecosystems. Funding for stewardship extended from public to private sources. Peatlands viewed as “essential to the nation’s wellbeing and natural capital.”

2050 and beyond

Rewards of restoration work now evident. The effects of climate change will be more apparent, but peatlands are coping. Restoration work continues, generating income which helps to maintain rural skills and employment.

 

 

 

 

 

"Peatlands". Science Scotland (Issue Twenty-one)
Printed from http://www.sciencescotland.org/feature.php?id=316 on 21/10/17 04:09:46 AM

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