Aapa mire: A mire complex with minerotrophic peat layer and pronounced surface pattern of wet flarks and hummocky mostly oligotrophic dwarf-shrub strings.

Acrotelm: Upper peat producing layer of mire with a distinct hydraulic conductivity gradient in which water level fluctuations and most of horizontal water flow occur.

Blanket bog: Bog in a very humid climate, which forms a blanket-like layer over the underlying mineral soil.

Bog (raised bog): Mire raised above the surrounding landscape and only fed by precipitation.

Catotelm: The lower permanently water saturated layer in a peatland, with relatively low hydraulic conductivity and rate of decay.

Cut-away peatland: What remains of a peatland after all the peat which can be economically removed has been extracted.

Fen: Peatland receiv¬ing inflow of water and nutrients from the mineral soil. Distinguished from swamp forest by a lack of tree cover or with only a sparse crown cover. Indistinctly separated from marsh (which is always beside open water and usually has a mineral substrate). See also minerotrophic peatland.

Flark: Elongated wet depressions with sparse vegetation (mud-bottom) in string mires; most of the time waterlogged or even flooded. Also called rimpi (Finnish).

Flood mires: Mires in which periodical flooding by an adjacent open water body (sea, lake, river) enables peat accumulation.

Fluvial mires: Mires associated with rivers.

Geogenous peatland: Peatland subject to external flows.

Hummock: Peatland vegetation raised 20-50 cm above the lowest surface level, characterized by drier-occurring mosses, lichens, and dwarf shrubs.

Infilling, terrestrialization: The process whereby peat develops on the margins and into the centers of ponds, lakes, or slow-flowing rivers.

Lagg: A narrow fen or swamp surrounding a bog, receiving water both from the bog and from the surrounding mineral soil.

Limnogenous peatland: Geogeneous peatland that develops on the ground along a slow-flowing stream or a lake.

Marsh: Develops mostly on mineral soil, but could be a peatland. Beside open water, with standing or flowing water, or flooded seasonally. Submerged, floating, emergent, or tussocky vegetation.

Mesotrophic peatland: Intermediate peatland between minerotrophic and ombrotrophic.

Minerotrophic peatland: Peatland receiving nutrients through an inflow of water that has filtered through mineral soil.

Mire: Synonymous with any peat-accumulating wetland. A peatland where peat is currently forming and accumulating.

Mire complex: An area consisting of several hydrologically connected, but often very dif-ferent, mire types; sometimes separated by mineral soil uplands.

Mixed mire: A mire type with bog and fen features or sites in close connection.

Moor: Synonymous of mire (Europe).

Muskeg: Large expanse of peatlands or bogs (Canada and Alaska).

Oligotrophic peatland: Peatland with poor to extremely poor nutrient levels.

Ombrogenous peatland: Peatland receiving water and nutrients only from atmosphere. Also called ombrotrophic. See Bog.

Palsa mire: Peatland complex of the discontinuous permafrost region, with palsas (peat mounds or plateaus usually ombrotrophic) swelling out above the adjacent unfrozen peatland (usually fen).

Paludification: The formation of marsh or waterlogged conditions: also refers to peat accumulation which starts directly over a formerly dry mineral soil.

Peat: Fibric organic sedentarily accumulated material with virtually all of the organic matter allowing the identification of plant forms; consists of at least 30% (dry weight) of dead organic material.

Peat extraction: The excavation and drying of wet peat and the collection, transport and storage of the dried product.

Peatland: An area with or without vegetation with a naturally accumulated peat layer at the surface of at least 30 cm depth.

Polygon mire: Permafrost peatland patterned complex which consists of closed, roughly equidimensional polygons bounded by cracks, with high or low centers, and often with ridges along the margins.

Primary peat formation: The process whereby peat is formed directly on freshly exposed, wet mineral soil.

Pristine mire: Mire which has not been disturbed by human activity in a way which damages its ecosystem.

Quaking bog (quagmire, quaking mat, floating mat, Schwingmoor): Mire in which the peat layer and plant cover is only partially attached to the basin bottom or is floating like a raft.

Raised bog: Deep peat deposits that fill entire basins, develop a dome raised above ground water level, and receive their inputs of nutrients from precipitation.

Riparian peatland: Peatland adjacent to a river or stream, and, at least periodically, influenced by flooding.

Sloping mire: Mire with a sloping surface.

Soligenous peatland: Geogenous peatland that develops with regional interflow and surface runoff.

Spring mire: Mire that is mainly fed by spring water.

String: Elongated ridges in patterned fens and bogs arranged perpendicularly to the slope with hummock or lawn level vegetation.

Swamp: Usually forested minerotrophic peatland. Separate from wooded fens due to a denser tree canopy. Also peat swamp forest.

Terrestrialisation: The accumulation of sediments and peats in open water. See infilling.

Topogenous peatland: Geogenous peatland with a virtually horizontal water table, located in basins.

Wetland: Land with the water table near the surface. Inundation lasts for such a large part of the year that the dominant organ¬isms must be adapted to wet and reducing conditions. Usually includes shallow water, shore, marsh, swamp, fen, and bog.

Wetland (Ramsar definition): Areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static, flowing, fresh, brackish or salt, including areas of marine water, the depth of which at low tide does not exceed six meters.