MI17 Mire restoration

>> Background information

Development

Restoration of drained mires aims to gradually restore natural mire hydrology and original mire vegetation. This is most often achieved by removing trees and filling or damming ditches.

The annual area of restored mires varies, but has in generel increased since mid 1990s. The years 2004 and 2005 marked a peak in the so far short history of mire restoration as approximately 2 000 hectares of mires were restored per year.

Mire restoration projects have concentrated almost entirely on protected areas on state land, although a small area (c. 200 ha) of  protected private land and forestry land has also been restored. In 2003 it was estimated that a minimum of 20 000 hectares of mires required restoration in protected areas managed by Metsähallitus Natural Heritage Services. By 2013 altogether 22 600  hectares have been restored.

Impact on biodiversity

Restoration of mires has a positive impact on biodiversity, because it allows a variable habitat to develop and thus increases the viability of threatened, vulnerable and demanding species. Recovery rate is largely species dependent. It has been reported, for example, that birds nesting on open mires have sought their way to the restored areas quite quickly after restoration. Many plant species of flark fens may on the other hand take longer to recover, since they usually disappear altogether when mires area drained. Migration from other areas after restoration is relatively slow.

Restoration increases the abundance of available habitats for mire species, but it does not automatically help all declining species. The effect varies within organisms and areas. In populations of Yellow wagtail, for instance, both increase and decline have been observed in different areas after restoration. However, restoration decreases the risk of population decline in the future and it may have a significant effect on local species diversity.