SPHAGNUM: PLANT OF LIFE

Sphagnum moss works as an “ecosystem engineer”, according to ecologist David Leach, because it actually shapes the habitat it lives in. David, the peatland restoration project officer for Dartmoor National Park Authority (DNPA), says: “Sphagnum moss actively lowers the soil pH, making it more acidic while creating anaerobic conditions [without oxygen], so waterlogged vegetation forms peat instead of rotting.”

Healthy moorlands with thriving mossy peatlands are great for the environment because they store vast amounts of carbon. Dartmoor’s peat soils lock an estimated 10 million tonnes of carbon – equivalent to one year’s CO2 emissions from UK industry.

Healthy peat bogs also store water. Nine rivers originate in Dartmoor’s peat and 45% of South West Water’s daily water supply falls as rain here. Peat bogs can act as a buffer, protecting lowland towns from flooding.

“During high rainfall, peat soaks up water and slows flooding. In drought, it releases water slowly into river systems.” Unfortunately, adds David, “Dartmoor’s southernmost bogs are degraded and riddled with gullies due to peat extraction and erosion, which drain the bog.” Other impacts on the health of peat bogs include overgrazing, climate change, reduced rainfall, and possibly acid rain and nitrogen deposits caused by air pollution.

Restoring peat bogs, and the health of the mosses that grow there, will help protect wildlife. Diving beetles and the carnivorous plant sundew live among the eight species of sphagnum found on Dartmoor. Ground-nesting waders, such as dunlin, rely on the cover of sward for protection from predators and the shallow pools are first feeding grounds for their chicks. DNPA aims to “re-wet” 750 acres of Dartmoor peatland by blocking up erosion gullies, drainage channels and peat cuttings.