MI12 Red-listed mire habitats

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Status of mire habitat types

A little more than a half of all mire habitat types were evaluated as threatened in a red-list assessment of Finland's habitat types published in 2008. The greatest percentage of red-listed habitat types was found in the groups of spruce mires, rich fens and spruce-birch fens. Negative development has been the strongest in southern Finland, where land use has been more intensive. Many nutrient-poor mire types, for example dwarf shrub spruce mires and fens have become more threatened in southern Finland in addition to the nutrient-rich types. However, local changes have occured also in the mires of northern Finland, even though the overall development has not been so severe.

Red-list assessment was also conducted separately for habitat type coplexes. Half of the mire habitat type complexes were found threatened. These include mire succession series of the land uplift coasts, wooded raised bogs and middle boreal lawn-surfaced aapa mires. All red-listed habitat type complexes were found in southern Finland.

Threats

Mires have been utilized for agricultural purposes in Finland for centuries. The exploitatioon became more intensive after the middle of the 20th century as more mires were drained for forests (see also MI1 and MI2). Peat production became extensive in the 1970s (see MI3). Other threats to remaining mire habitats include fellings of wooded mires, soil treatment, construction, road network, groundwater extraction and the effects of watercourse regulations, for example artificial lakes and clearing of small brooks.

Decrease in the amount of mires still occur, but it has become a lot slower since the beginning of the 21st century as draining of pristine mires has mainly been given up. For the remaining mires to sustain it is important that their water resources are kept undisturbed. Land use and water construction may have long-distance effects on mires even further away. Ditch clearing, for example, often affects also the hydrology of undrained mires. Because of this the quality of mires in southern Finland is still decreasing.

Global change may in a long term affect the mire habitat types. As climate temperature rises, palsa mires and pine mires of northern Lapland are the first mire types which will become threatened, since they are closely linked to ground frosting. Because of this threat palsa mires were classified as near threatened in the red-list assessment.