Re-flooded peatlands could unite the bioeconomy with conservation

Peatland covers just 3% of global land surface but stores twice as much carbon as the world’s forests combined.

Despite its rarity and importance, the habitat has on the decline for centuries. Farmland expansion and the over-extraction of its dark, nutrient-rich soils by the horticultural industry have been the main drivers.

Policymakers in Germany, Ireland, and the UK are now trying to encourage regenerative forms of agriculture that could conserve peatland while drawing on its unique ecosystem for fuel, fodder, food, and construction materials.

Peat microorganisms filter aquaculture waste

In the Republic of Ireland, the government has been experimenting with peatland aquaculture. Ireland’s seafood development agency has trialled the method at “Oasis” fish farm in Mount Lucas Wind Farm, situated on Mountlucas bog: a 1, 000 hectare peatland habitat near Daingean in the centre of the country.

The trial had four culture pounds with eight comportants for rearing European perch, rainbow trout, common duckweed, and gibbous duckweed. Everything is on a former cutaway site, a pit where peat was previously extracted from, and the wind farm generates all the energy required for the farm.

Every aquaculture system needs a way of removing fish waste so toxins do not build up. In modern raceway aquaculture, where fish are raised in artificial ponds, solid wastes are often released directly into natural streams nearby.

In the Irish peatland system, natural organisms perform the waste management. The fish ponds are connected to a block of 16 lagoons filled with living algae and duckweed that act as living water filters. In a study sample, 20 genera of algae in the fish ponds were identified. This community of organisms means that raw, untreated wastewater does not enter the natural water systems. Ireland’s peatland fish farms comprise a nature-based system that leans on the unique flora and fauna of the habitat to maintain an optimal rearing environment.

New peatland economies could support climate goals

The Irish peatland aquaculture trial was set up in order to solve several interlocking problems.

First is the biodiversity crisis. As elsewhere in the British isles, Irish peatlands are under threat and setting up sustainable industries on the land aim to prevent more ecologically damaging activities from encroaching. With the ecosystem doing most of the work in processing the fish waste, it can also be far less polluting of waterways than modern aquaculture.

The Irish aquaculture experiment is also a climate mitigation and a food security measure, a means of developing a food system that does not require the carbon intensive footprint of intensive livestock rearing.

Peatland aquaculture systems could also support adjacent, higher-value bio-industries to form around it: the microalgae used in water purification could be harvested for ingredients in new food and packaging. Some have argued the project, which could create low carbon local jobs, could provide a model of sustainable development that could be replicated in similar habitats around the world.

The carbon problem of drained English peat

Although peatlands are powerful carbon sinks in their undisturbed state, land conversion can turn it into a huge source of emissions.

Eastern England is famous for its once-extensive peatland habitat, known as the fens. Although tracts remain, it’s now only 16% of its size in 1850. Over the last 500 years, peatlands around Europe were drained and its fertile soils given over to intensive farming.

Draining the wetlands have not just destroyed a unique ecosystem and its wildlife. When peatland soil becomes dried out and farmed, its peculiar chemistry means it releases large amounts of carbon. Shockingly, while drained former peatlands cover only 0.3% of the world’s land surface they emit 4% of anthropogenic global greenhouse gas emissions.

A return to water

Farmers and policymakers recognise the carbon leakage of drained peatland as a huge issue. To reduce emissions, the fens would have to be re-flooded, something that would restore the peatland to its former boggy glory. Of course, this would mean losing vast acreages of some of what is now among the most highly productive farmland in Britain.

The drive to rewet farms that were former peatland is now a national policy issue. The problem is ensuring that the land can still support local incomes once the land is flooded again.

The UK government has recommended a policy pathway that combines nature restoration with biobased industries. The solution lies in finding new, low-intensity farming that could allow for the exploitation of some rewetted peatland areas as well as more sustainable farming for areas that cannot be fully flooded again.

For rewetted areas, something known as paludiculture is a possibility. This is a form of agriculture that takes place in flooded landscapes. New crops and working methods would have to be found but a Defra funded review stated that paludiculture could make a valuable contribution to climate change mitigation and adaptation while sustaining the economic output of the conventional agriculture currently occurring on the peatland.

In August 2022, the British government announced a £5 million fund to promote sustainable peatland farming. It argues that although re-flooding farmed peatland would result in an immediate loss of agricultural productivity, the long term environmental and carbon improvements would bring net benefits. The England Peat Action Plan published in 2021 recognised that while the cost of restoring all UK peatlands to near natural condition would be between £8.4 to £21, 3 billion, doing so would deliver environmental benefits of £109 billion.

Thatched rooves and sustainable clothing

Germany also hosts large peatland areas that have been degraded through conversion to farming. For several years, the government has launched strategies and programs for rewetting historic peatland in a way that sustains local economies with new crops and value chains.

One of the ways that rewetted peatland could contribute to the economy would be the provision of biobased building materials. The most important historic building materials that came from peatland species was reed, the material used in thatched roofs.

Germany has an import dependence for the reed material used in thatched rooves. This is one of the target areas of the government’s peatland economies project. Typha, the species that provides thatch reeds, is fast-growing and stores high levels of carbon, making it a potential candidate for a low-impact peatland bioeconomy crop. Aside from roofs it can be used in paper production and can replace plastics in the industry.

Germany’s Paludi-PRIMA project is looking for other plant species and crop management techniques that could found a larger peat agricultural system. The aim of the German government’s plan is that water-loving species could return and provide the basis of a stable industry so that the habitat is protected.

Typha could also provide fibres for textiles. In 2023, British biomaterials company Saltyco announced it is working with the Wildlife Trust, a independent wildlife charity, in Lancashire, Manchester and North Merseyside to cultivate and process bulrush crops on restored peatland into a goose feather replacement in padded jackets. The R&D project has received £400,000 funding from the UK government’s Paludiculture Exploration Fund.

Sphagnum moss: peatland’s alternative to peat

Another candidate crop for a restored peatland bioeconomy is sphagnum moss. This prolific peatland species has many biotechnological uses. For example, it can be used as a biobased tool for environmental monitoring. Mosses take up elements and nutrients via their surface, they can be used to detect the chemical composition of their surroundings.

Sphagnum could also provide an alternative horticultural medium to peat soil. The extraction of peat for horticultural use has been one of the main drivers of peatland habitat destruction over the last two centuries. However, sphagnum moss offers the nutrient and water-retaining properties of peat while also being a more renewable material.

In North Cambridgeshire, home to part of the great East Anglian fens, a project has begun in 2023 to trail a working wet farm on the peatland. Speechly’s Farm won a lottery heritage fund to grow typa bulrush and sphagnum moss.

Speechly Farm’s project linked up with experts in Lower Saxony, Germany, to work out ways of cultivating sphagnum moss. The main market for sphagnum moss is horticulture right now but new products and markets are on the horizon, including biobased building materials.

The British agriculture and environment agency DEFRA have researched sphagnum farming as a means of replacing peat use in horticulture as part of its own research into the possibilities of paludiculture.

According to the agency, a total of eighty-eight native UK wetland species have been identified with economic potential. Wet meadows can support diverse species that serve as animal fodder as well as delicacies like blueberry and elderberries. Working out regenerative forms of peatland agriculture for these crops could achieve that elusive balance between industry and habitat preservation.

The longer frame

There is still a long way to go before we see the US bioeconomy plan translate into more biobased production capacity on the ground as it remains in its planning stages. The plan tasked many government agencies to conduct around 40 scoping missions on the policy, economic, and technological aspects of the new bioeconomy. Only a few have so far been completed.

However, as the size of the raw material pool and supply chain infrastructures are major limiting factors on bioeconomy scaling, the USDA report marks an important step in planning for implementation.

In the final instance, the bioeconomy plan will also need support from and cohesion with other domains of policy. A good example is agriculture, where policymakers need to assess the kinds of crops, technologies, and economic support will be needed to hit 1.2 billion tonnes of biomass in a more volatile climate.