Sphagnum Moss

Sphagnum are a group of mosses (opens new window), over 30 of which are native to the UK, that play vital a role in upland ecosystems. These keystone species are Priority Species under the UK Post-2010 Biodiversity Framework and protected by law under the Wildlife and Countryside Act, 1981. As a keystone species, their presence is essential to develop healthy ecosystems in the habitats they occupy.

Their water absorbing properties, allowing them to store 20 times their weight in water (opens new window), are so powerful that the moss was used as a field dressing to dry wounds during the First World War (opens new window). This allows them to retain water in upland areas that would otherwise run down into the valleys below. Not only does this create important wetland bog habitats, but it also reduces the flood risk to towns and villages in the valleys below, by reducing the amount of water being flushed from the moors, particularly after storm events. The water that does eventually leave the bog is also cleaner, as sphagnum mosses help to reduce the amount of sediment displaced and transported by the water. Water companies spend thousands of pounds removing sediment from water, so improving the number and function of these mosses could help customers to save on their water bills by doing some of the cleaning for free.

Perhaps their most underappreciated role is as the founding keystone species of these important peatland bogs. Bog mosses do not decay when they die, instead forming peat as they are compressed by newer individuals growing on top over centuries. This drives the bog to become increasingly acidic and nutrient poor. The lack of nutrients makes these environments hostile to most species, but creates havens for specialists including sundews, butterworts and bladderworts (opens new window), carnivorous plants that are able to make up for the nutrient deficit by consuming invertebrates inhabiting the bog. Golden plover and dunlin wade the moors, predating invertebrates, but could in turn be predated by birds of prey including hen harriers and short-eared owls. The bogs also support a rich variety of invertebrates including dragonflies, darters, butterflies and hawkers. However, since the industrial revolution, British moors have been heavily degraded due to a combination of heather burning for grouse shooting and grazing, and pollution in areas closer to cities. Many hectares of once great uplands lie as barren bare peat across the country.

Without sphagnum mosses, these areas would remain as bare peat, harbouring almost no life at all. However, when sphagnum is plug planted at densities of as low as 5 plugs per m2, it will grow and spread, with restored areas seeing 100% vegetation cover after 6 years and blanket bog indicator species returning to full swing in less than 10 (opens new window). Once the moss establishes it creates a chain reaction as soil moisture increases in areas where moss is retaining water, sediment erosion is reduced and the habitat becomes more suitable for other species to begin to play their role in the ecosystem.

However, there is very little scope for 'natural' re-establishment of the moss in degraded areas, and it very rarely recolonises sites without being actively introduced. The uplands have been actively degraded by human activity, and will only be restored with assistance from human hands. With enough support, sphagnum moss can be re-established across the North of England and help restore our uplands in as little as 10 years.

Sphagnum balticum (Baltic bog-moss)