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Restoration of raised bog Holmegaards Mose (HOLMEGAARD MOSE)
Date du début: 1 janv. 2010, Date de fin: 31 déc. 2013 PROJET  TERMINÉ 

Background Denmark has carried out a national assessment of the conservation status of habitat types and species covered by the Habitats Directive. The main threats to the habitat *7110 ‘Active raised bogs’ was recognised to be desiccation, overgrowth with trees and scrubs, and fragmentation. In the planning process to develop management plans and actions plans for all Natura 2000 sites (according to the Act on Environmental Objectives), it was recommended that the restoration of sites with active raised bogs be prioritised. This recommendation reflected the likelihood that the national conservation status of this habitat type would further deteriorate during the first planning period of 2010-2015 without any preventative action. The LIFE project would focus on the largest active raised bog area in Eastern Denmark –dHolmegårds Mose – which was exploited for more than a century to provide fuel for glass production and for heating purposes. But parts of the active raised bog remains and the site still has the potential to develop large areas mainly covered with *7110 Active raised bog. The project site is situated in the southern part of the island of Zealand. Objectives The overall objective was to restore and maintain at a favourable conservation status areas in Denmark of *7110 Active raised bog. It planned to restore conditions to ensure a development of the main part of Holmegårds Mose into *7110 Active raised bogs at a favourable conservation status. A secondary objective was to restore the conditions to ensure favourable conservation status for *7230 Alkaline fens, *7140 Degraded raised bogs still capable of natural regeneration, *7210 Calcareous fens with Cladium mariscus and species of the Caricion davallianae – with a preference for maintaining, or if possible expanding, the area of the habitat for the orchid species Liparis loeselii. Results The project achieved its main objective to restore conditions that ensure a development of the main part of Holmegårds Mose into *7110 active raised bogs at a favourable conservation status. Around 70 ha of bog were restored. The increase of sphagnum in the restored areas is significant as it is a sign of both improved hydrology and light conditions. All actions connected to the secondary objective were implemented, but mapping activities carried out in 2010 are not able to show any improvements. However, a population of the fen orchid (Liparis loeselii) in the northernmost project area was surveyed every year of the project. The monitoring showed that the size of the habitat for fen orchid decreased significantly during the LIFE project. The variations in population size, at least during the last years, primarily reflect variations in water regime. The Natura 2000-plan 2010-2015 for Holmegaard Mose highlighted the conflicting interests of a simultaneous goal of both restoring active raised bog and improving habitat for fen orchid. The latter requires a humid, calcareous substrate created by peat cutting (where the vegetation is in contact with the calcareous bottom of the former lake). According to the plan of the LIFE project, the water table in this area is expected to rise by up to 25 cm. The Natura 2000 plan resolves this conflict by prioritising raised bog restoration. A key hydrological action carried out by the project was the flooding of Glasværksengen (Glaswork meadow) with the purpose of cleaning the surface water and groundwater before running it through the bog. Measurements of the nutrient load of the incoming water conducted prior to the project revealed significant loads of nitrogen and phosphorus. New measurements after implementation of the hydrological action on Glasværksengen indicated that the nutrient load was reduced significantly. Along with field measurements, this information helped inform a renewed strategy, which was outlined in the After-LIFE plan. Significant results of the project included: Hydrological restoration on 70 ha out of the 90 ha foreseen (It was decided not to implement the action on 20 ha due to high nutrient levels which would actually damage the bog area.); Clearing of secondary birch wood carried out on 96 ha out (four more than foreseen); Grazing on 31 ha of the area using a dynamic grazing regime with mobile fences (The rest of the targeted area 50 ha is being managed by hand as this was considered to be the most suitable long-term management method for the area.); Two leaflets produced and excellent information boards erected; Creation of a watch tower, paths and board walk; and Biological monitoring conducted throughout the project time and water level monitoring during the last years.A rough estimate of the environmental benefit of the LIFE project was obtained by comparing an orthophoto after the clearings with data from the initial habitat mapping in 2004. Such a comparison gives a net gain, as a result of the project, of 52 ha *7110 Active raised bog + 7120 Degraded raised bog. Given that a certain amount of the 2004 mapped area of *7110 was covered with birch, this area was also added to the total 52 ha, giving a growth of 70 ha, as quoted above. It is assumed that with the continuous growth of peat mosses – as documented by the monitoring programme – will gradually result in more patches of degraded raised bog becoming active raised bog. The LIFE project, in short, represented a cost-effective way of tackling the overgrowth of the entire bog with birch and purple moor grass. Taking such action at a later date would have been more expensive. With the Danish Nature Agency as the managing authority, there is now an obligation to continue to manage the area – and a staff member was hired full time for this task. Additionally, should a management cooperation arrangement be concluded with the Næstved Municipality, as expected, a skilled supervisor is likely to be employed on a seasonal basis. The restoration of the largest raised bog in eastern Denmark will preserve the locality as a unique destination accessible to the public. The dissemination activities of the project and the associated measures (such as the construction of a viewing tower) have improved the quality of recreation at the site. Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).

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