Peat

What are peatlands?
Peat is formed by the accumulation of undecayed plant material. The term peatland refers to any wetland that contains peat, including those sites that no longer support the natural peat-forming plant species that once inhabited the area. A mire is a wetland that supports at least some of the vegetation that is normally peat forming.

Fens are mires which receive water, nutrients and minerals from the soil, rock and ground water as well as from rainfall. Peat-forming mires which are fed purely by atmospheric precipitation - i.e. rainfall, snow, mist and dust alone - are termed bogs. Two main types of bogs have been described in Britain, blanket bog and raised bog.¹

Blanket bogs
In the UK blanket bogs tend to exist where conditions are harsh e.g. in northerly or upland areas. Their formation requires a persistently wet and cool climate, in order to allow the growth of peat forming Sphagnum mosses. The acidic, waterlogged environment ensures plant decomposition rates are low, resulting in peat formation which spreads over large areas of gently sloping ground as well as hollows and flat ground to form an extensive 'blanket' of peat.² It is one of the most extensive semi-natural habitats in the UK and ranges from Devon in the south to Shetland in the north.³

Lowland raised bogs
Raised bogs are found mainly on low plains or broad valley floors. They are formed from the decaying remains of plants, such as Sphagnum mosses, which retain large amounts of water and form a dome of peatland many metres deep.⁴

Why are peatlands important?
Peatlands are of great ecological, cultural and archaeological interest. Since they are acidic and low in nutrients decay barely takes place. They therefore contain an irreplaceable archive of past climate, vegetation and human activity dating back thousands of years. In addition, peat bogs play an important role in the regulation of the world's climate. Referred to as 'global coolers,' they remove carbon from atmospheric CO2 and serve as valuable 'CO2 sinks.' Unless disturbed by human activities, such as peat extraction, this carbon can be stored for near geological time periods.⁵

Lowland raised bogs
Lowland raised peat bogs are one of the most important wildlife habitats in the UK, being of both national and international conservation interest. There are few intact examples remaining and they form a unique and fascinating home for many rare and threatened species. These include important populations of wild birds, such as the nightjar, marsh harrier and long-eared owl. They also support a wealth of unusual plants such as the giant sundew (Britain's largest carnivorous plant) and thousands of species of rare insect.⁶

Blanket bogs
The UK contains 16% of the original world distribution of blanket bog. This makes conservation of blanket bogs a priority under the Habitats Directive.⁷ The bird populations of blanket bogs are of particular conservation importance and several are of international interest for either their rarity or for the densities of their breeding populations on blanket bogs, for example red-throated diver (Gavia stellata) and Eurasian golden plover (Pluvialis apricaria). A number of important moths, butterflies (large heath), dragonflies (azure hawker), tipulids and beetles (Oreodytes alpinus) also occur on blanket bogs.⁸

Fens
The UK is thought to host a large proportion of the fen surviving in the EU, and some of these areas are of international importance. Fen habitats support a diversity of plant and animal communities. Some can contain as many as 550 species of higher plants - a third of the UK's native plant species; up to and occasionally more than half the UK's species of dragonflies, as well as being an important habitat for a range of aquatic beetles and several thousand other insect species. Bearded tits and marsh harriers can also be seen in fen habitats.⁹

What are the threats facing peatlands?

Agriculture and afforestation
Much of the UK's peatlands have been degraded by, or entirely lost to, agricultural 'improvement' (usually through drainage) and commercial forestry operations. The delicate hydrology of peatlands can also be affected by agricultural and commercial forestry activities in adjacent areas - for example if they result in the water table being lowered.¹⁰

Peat extraction
Peat bogs have been exploited by humans for many years. Traditionally peat was cut by hand and, being a slow method, this allowed some moss vegetation to regenerate. Since the 1960s, however, major commercial companies, such as Scotts, have introduced more intensive methods of extraction. These have resulted in the unsustainable 'mining' of peat. The UK's raised peat bogs have now been reduced to a fraction of their original extent. In 1996, of an original 69,000 hectares, only 5.5% (3,836 ha) of lowland raised bog could still be described as in a 'near natural' state.¹¹

What is peat used for?
Unlike some European countries where peat is extracted commercially for fuel, in the UK the use of peat is almost entirely related to horticulture.¹² Approximately 3.39 million m3 of horticultural peat is used annually in the UK (down 1% from 3.43 million m3 in 1999). It is used as both a soil improver and a growing medium, with these two categories respectively accounting for 3% and 97% of the market.¹³ Soil improvers mainly consist of peat alternatives (94%) and growing media are still mostly comprised of peat (90%).¹⁴ Growing media in mainland Europe also tend to be predominantly peat-based.¹⁵

The use of peat as a soil improver has declined in recent years - largely due to the availability of cheap, high quality, alternatives such as green compost and bark. In a survey conducted by the DETR (Department of Environment, Transport and the Regions) the majority of local authorities, landscape contractors and amateur gardeners questioned agreed that it was a waste to use peat for soil improvement. Resistance to the use of peat alternatives in growing media remains fairly strong however, particularly among professional growers.¹⁶

The use of peat in horticulture is almost completely unnecessary¹⁷. Prior to the 1960s gardeners used a wide range of alternatives to peat. Since then, aggressive marketing by companies such as Scotts managed to convince the gardening and landscaping world that peat was an indispensable component of successful horticulture. For several years now this view has been challenged. As the late Geoff Hamilton put it "I think that gardeners buy peat because of brain conditioning rather than soil conditioning".¹⁸