Peatlands

What are peatlands?

Peatland is a terrestrial wetland ecosystem in which the production of organic matter exceeds its decomposition and a net accumulation of peat results.

Peatlands occur in every climatic zone and continent. The total area globally is around 4 million km2 making them 70% of natural freshwater wetland or 3% of the Earth’s land surface. Peatlands include landscapes that are still actively accumulating peat (mires), others that are no longer accumulating and do not support the principal peat forming plants (e.g. Sphagnum spp.), and peatland used for economic uses such as agriculture, forestry and excavation for energy generation, horticulture and a few other.

Boreal and temperate peatlands

The majority of the world’s peatlands occur in boreal and temperate parts of the Northern Hemisphere, especially, Europe, North America and Russia where they have formed under high precipitation-low temperature climatic regimes.

Tropical peatlands

In the humid tropics, regional environmental and topographic conditions enable peat to form under conditions of high precipitation and high temperature in Southeast Asia, mainland East Asia, the Caribbean, Central America, South America, Africa, parts of Australasia and a few Pacific Islands. Most tropical peatlands are located at low altitudes where rain forest vegetation grows on a thick layer of organic matter although some are found in upland or mountainous areas where peat can exceed 30 m. The largest area of tropical peatland is in Southeast Asia.

Mire

In the humid tropics, regional environmental and topographic conditions enable peat to form under conditions of high precipitation and high temperature in Southeast Asia, mainland East Asia, the Caribbean, Central America, South America, Africa, parts of Australasia and a few Pacific Islands. Most tropical peatlands are located at low altitudes where rain forest vegetation grows on a thick layer of organic matter although some are found in upland or mountainous areas where peat can exceed 30 m. The largest area of tropical peatland is in Southeast Asia.

Wetland

Wetland is a landscape experiencing high amounts of water at the surface, either permanently or for considerable periods in the year. Waterlogging can be by fresh or saline water and in extreme cases the surface can be inundated. Wetlands are dynamic systems, which form part of the hydroseral continuum from open water to dry land a process that takes place over thousands of years and all stages of which may not be evident in every location. Mires and peatlands are specific types of interrelated wetland with the unique potential to accumulate dead organic matter as peat, often to considerable thickness.

The Ramsar Convention on Wetlands (Article 1.1) adopts a broad approach to wetlands considering them to be ‘areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine waters the depth of which at low tide does not exceed 6 metres’. Also included are wetlands that have been impacted or made as a result of human activity and those restored as nearly as possible to their former natural or an alternative condition.

Wetlands occur in all climatic zones from tropics to tundra and on every continent, except Antarctica. The global area of wetlands and the carbon they contain are subject to considerable debate and reliable data are difficult to obtain or distinguish from peatlands. The global area of wetland ranges from 280 to 398 million hectares , 1993) while an assessment for the Ramsar Convention suggests it is in the region of 5.7 million km2, equivalent to 6% of the Earth’s land surface.

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