Denmark: Restoration of Dune Habitats along the Danish West Coast

Project Stage:
Completed

Start Date:
2001-11-28

End Date:
2005-11-28

Primary Causes of Degradation

Degradation Description

The main threats to the dune habitats are the large-scale invasion of non-native species, lack of natural dynamic processes (i.e. over-stabilization), and eutrophication. The species invading the dune heaths are mainly Pinus mugo and Pinus contorta. The trees are spreading from the dune plantations established along the Danish West Coast more than 100 years ago to mitigate dune mobility. The encroachment of these and other woody species creates a shadowing effect that alters the microclimate of the region and disrupts natural processes of nutrient circulation. These changes in the ecology of the dune heaths jeopardize native biodiversity and imperil the longevity of the ecosystem.

Reference Ecosystem Description

Dune heaths are characterised by great variation – both in terms of the terrain and the animals and plants which live there. The dynamic dune heath is a mosaic of dry plains, moist hollows, shallow lakes, and dune formations. The plains are dominated by crowberry (Empetrum) and heather (Calluna), and the vegetation in the hollows includes bell heather (Erica), bog whortleber¬ry (Vaccinium), purple moor grass (Molinia), bog myrtle (Myrica), and willow (Salix). In the dunes, the vegetation is dominated by sand sedge (Carex), helmet, grey hair-grass (Corynephorus), and lichen.

Several species of herpetofauna inhabit the dune heath ecosystems, including Bufo calamita, Rana arvalis, Lutra lutra and Triturus cristatis. The dunes also provide important habitat for many common and rare species of birds, Grus grus and Tringa glareola among them.

Project Goals

The project goal was to restore threatened and vulnerable coastal dunes and dune heathlands along the
Danish West Coast, in order to regain a favourable conservation status for the area. This objective was to be obtained through the following field activities:

– Clearing of 542 ha of dense overgrowth (overgrowth degree III).
– Removal of tree encroachment on 3452 ha (overgrowth degree II).
– Management activities on more than 2800 ha in order to counter threats from nutrient enrichment and lack of natural dynamics (overgrowth degree I).
– Restoration of natural hydrology on site 72 (Lyngbo Hede) and site 78 (FanÁ¸), and restoration of dune heath on site 184 (Stenbjerg).
– Land swaps on roughly 36ha on site 78 (RÁ¸mÁ¸), in order to remove land-ownership related barriers to habitat management.
– Restoring natural hydrology in the project areas containing decalcified fixed dunes with a mosaic of humid dune slacks in order to secure viable populations of amphibians, primarily Bufo calamita and Rana arvalis.

Monitoring

The project does not have a monitoring plan.

Description of Project Activities:
Measures were taken to restore hydrologic processes at several of the project sites. A 1-kilometre long drainage trench, up to 3 metres deep and 3 metres wide, from the 1960s traversed site 72, Lyngbo Hede, and drained the dune heath and the nearby holiday cottage area. Groundwater measurements at 22 points within the project area showed that the trench had a significant drainage effect on the southwestern part of the heath, lowering the groundwater table up to 1,5 m in the summer and thus having a significant effect on the low-lying wet areas. A preparatory project was conducted in order to determine the most feasible way to restore the natural hydrology on the dune heath, without negatively affecting the holiday cottage area. The restoration was done by laying down pipes in the trench on a 630-metre stretch, including outlet mechanisms for extreme conditions, ensuring that the drainage effect on the heath is significantly reduced, while the holiday cottage area will not be negatively impacted. The pipes were covered with materials from the heath, ensuring that the natural undulating landscape was maintained. Hydrologic issues were also addressed on two other project sites. At sites 78 and 184, drainage trenches were closed in order to restore natural hydrology, and thereby expand the wet habitats on the dune heath and maintain the mosaic pattern of microhabitats in these areas. A shallow trench on site 78 (FanÁ¸) was closed in 2005, resulting in a longer retention of surface water in the area during the summer and a raised water table that will assist in keeping the area free of invading trees. On site 184 (Stenbjerg-Lodbjerg), several such trenches were closed. Because project expenses turned out to be much lower than initially foreseen, it was decided to close trenches at other sites, including site 26 (Á…lvand). The eradication of invasive trees and/or unwanted vegetation proceeded according to predetermined categories for the degree of overgrowth observed at a given site. Forest stands categorized as having overgrowth degrees of IV or V (i.e. the most densely overgrown) were selected for conversion through felling, chipping and removal of unwanted material. These areas were mainly old plantations of Pinus mugo and Pinus contorta, which were planted more than 100 years ago in order to halt the sand drift. The areas selected for felling were often protruding as narrow strips into the dune heath, and removal of these plantations created a much more coherent dune heath landscape. High priority was given to clearing of stands in low-lying wetter areas, as this is believed to give the highest return in terms of biodiversity benefits for birds and amphibians. The trees were felled either by machinery or motor-manually, according to the local conditions. The trees were then converted to wood chips, and typically sold to district heat plants. The original target was to manage 264,3ha under this action, and the end result of 388,1ha managed is therefore very satisfactory. Areas where tree encroachment had taken place over a period of up to 50 years were assigned to overgrowth degree III and selected for clearing. The trees were felled motor-manually and transported out of the area. In hilly terrain or wet areas, where the use of machinery would be too damaging, the trees were collected in small heaps and burned. In flat areas, smaller trees and bushes were destroyed using a tractor-mounted mulcher. In areas with overgrowth degree II, self-sown trees (mainly non-native species, primarily Pinus mugo and Pinus contorta) were felled and removed, or mulched. The trees have invaded the dune heath from nearby plantations, and removing them at this early succession stage reduces the risk of significant biodiversity loss. It also reduces the cost of future management efforts to keep the dune heath in a favourable conservation state. Solitary trees were felled and collected in heaps, which were burned. Smaller trees growing in patches on flat areas were removed by a tractor-mounted mulcher. In the areas designated as overgrowth degree I, a variety of techniques was used to clear vegetation. Low-intensity grazing was introduced or extended in some selected areas. In order to maximise the nutrient removal, no supplemental fodder was provided for the livestock. On state owned land, the grazing rights were leased out to local farmers, but as the grazing value was very limited, no profits were gained from this. In other overgrown areas, mosaic burning was employed in lieu of grazing. The burning of dune heath in a mosaic pattern of small irregular patches is, in many places, a very efficient management tool. In order to control the fire, the vegetation is usually cut (with a tractor-mounted mulcher) in a narrow belt around the areas to be burned. Thereafter, on the lee side of the belt a small counterfire is started, before the actual fire is started on the windward side. The shape of the burned areas is undulating and set according to the local conditions in hopes of achieving a more "natural" look. Burning takes place mainly in February and March, and only outside the breeding season of birds and other inhabitants of the dune heath. Some weather conditions are not suitable for burning, and delays were sometimes experienced due to wet spring weather. Even on project sites very close to residential or holiday cottage areas, burning has taken place without any incidents, although great care was taken to inform the local people about the action. In areas where the terrain is very flat, cutting and removing unwanted vegetation was done using tractor mounted harvesters. In some areas, all the vegetation had to be cut, but in most of the selected areas a mosaic pattern was applied, meaning that only about 20% of the area was directly cut. In some cases, land swaps had to be arranged in order to make certain areas accessible for management activities. On the island of RÁ¸mÁ¸, for instance, long and narrow strips of privately owned dune heath areas on site 78 were a barrier to coherent management efforts. The Directorate of Food, Fisheries and Agricultural Business (DFFE) under the Ministry of Food, Agriculture and Fisheries had holdings on the island outside of the target area, and agreed to acquire the private lots as part of a larger land consolidation scheme. Twenty different private owners were involved, and the transactions were complicated and time consuming. DFFE arranged to swap the lots inside the management area with holdings outside, and then the National Forest and Nature Agency purchased these lots from DFFE. Once these transactions had been completed, management activities could be conducted on the newly acquired land. Public outreach and awareness activities were important throughout the project as a means of communicating project objectives, activities, and outcomes. Map tables with information about the dune heath habitats in general, and the specific site in particular, were set up on 30 locations to help educate the public. The project website was created at the beginning of the project, and was used for publishing reports, news and other materials. At the end of the project, a layman's report was produced to make relevant information and findings accessible to non-experts. Throughout the project, local newspapers often published special stories about project activities, and several guided tours of the sites were conducted. A video was also produced in association with the project in order to disseminate information to a wider audience.

Ecological Outcomes Achieved

Eliminate existing threats to the ecosystem:
The successes and failures of methodologies applied in this project will not be entirely clear until some years after the project end date. However, the monitoring reports from the intensive as well as the extensive monitoring activities indicate that the methods applied have generally had a positive impact on the conservation status of the dune heath areas involved in project activities. Three hundred eighty-eight hectares of plantations, 516 hectares of dense overgrowth, and 4,972 hectares of tree encroachment areas were cleared of invasive vegetation and non-indigenous trees as a direct result of the project. Furthermore, grazing, burning and cutting were also carried out on 2,909 hectares. At the time of its completion, the project had managed to restore a larger area than was originally projected. Bufo calamita has started breeding in, and has thus successfully colonized, two new breeding ponds at GrÁ¦rup Strand (site 73). The species has also colonised an area at Lodbjerg (site 184) where the vegetation was removed, although without breeding success thus far. Rana arvalis is successfully breeding in large numbers at site 184 and site 26 where the vegetation has been mowed, and at site 185 and 78 where grazing has been introduced. Furthermore, Triturus cristatus has been found breeding on site 184 in an area where the vegetation has been cut down around a small pond. This habitat is a bit unusual for the species, but it is hoped that the population will remain there.

Factors limiting recovery of the ecosystem:
Obstacles encountered in the implementation of management strategies were primarily of an administrative character and generally beyond the control of the project management. The interface with property owners at or near the designated sites proved especially difficult, as land use issues repeatedly stalled project activities. In general, private landowners were reluctant to enter into management agreements, and this led to withdrawal of project areas on several sites. At site 72, Lyngbo Hede, the restoration of natural hydrology through the filling of the drainage trench was repeatedly delayed by disputes with property owners who feared that their cottages would be adversely affected. Elsewhere, property owners were reluctant to give their consent for tree felling, as they feared a reduction in trees would result in less deer, and thus less income from hunting licenses. Finally, securing the cooperation of livestock owners in restorative methods involving grazing was difficult at times, as EU subsidy reforms introduced during the project's implementation resulted in unforeseen changes in local economic patterns. Despite these difficulties, however, many property owners were encouraged by project activities and volunteered to enlarge the management areas beyond what had been previously pledged. Furthermore, there were some cases in which landowners who had not participated initially approached project practitioners and asked to have their properties included. For instance, a private fund that owns large nature areas with the specific purpose of nature conservation and animal protection (Aage V. Jensens Fond), actively asked for the inclusion of additional dune heath areas in the project activities on site 2 (RÁ¥bjerg Mile). Overall, the withdrawal of some privately owned areas was more than compensated for by the inclusion of other areas, both private and state owned.

Socio-Economic & Community Outcomes Achieved

Economic vitality and local livelihoods:
The Danish coastline bordering the North Sea is famed for its long stretches of white sandy beaches and extensive dunes. Consequently, income from tourism is becoming more and more important in this area, as many people visit the Danish west coast with the purpose of experiencing the vast open areas and unspoiled nature. In fact, two of the Natura 2000 sites included in the project (184 and 26) are part of the area currently being considered in political discussions for designation as one of the first Danish national parks, which is to be established in 2008. A socio-economic analysis conducted in connection with the development of the proposal indicates that establishment of a national park in the area will have significant income generating effects, particularly in the tourism sector. With this potential for tourist revenue in mind, the rehabilitation of dune habitats can be seen as an investment for local agencies and individuals.

Key Lessons Learned

The methodologies applied in this project are innovative and have already been used in other dune heath areas–private as well as state-owned, and both inside and outside of Natura 2000 areas. Methods of clearing plantations and mosaic burning have attracted international interest among relevant authorities, and a cooperative exchange has been established between Dutch and Swedish entities.

Long-Term Management

Vigorous new growth of Pinus mugo has been found in parts of the mechanically cleared and burnt areas, which underlines the need for a fast and consistent follow-up of the clearing work already carried out. If conservation work in the form of the removal of new growth of Pinus mugo (which can be carried out by hand) is not implemented within the next few years, the extensive clearing work will have been wasted.

It is deemed that annual inspection and clearing will be necessary for a 5-year period after the first major clearing. It will subsequently be possible to reduce the frequency of inspection and clearing to every three to five years.

It is recommended to continue monitoring of the habitat in the areas based on the previously laid out permanent sampling areas and transects. In this way it will be possible to assess whether the vegetation dynamics are developing as expected, and the need for any conservation measures in order to achieve the goals for the Atlantic coastal heath habitat can be continuously evaluated.

Due to the difficulties experienced in getting grazing agreements with stockowners, some areas where grazing would be the optimal management activity may have to be managed through mosaic burning and mowing instead.

Sources and Amounts of Funding

4,675,796.00 Euros Funding was provided by the European Union’s LIFE program, the financial instrument established to support environmental and nature conservation projects throughout the European Union.

Other Resources

Hanne Stadsgaard Jensen
Project Manager, Thy State Forest District
Danish Forest and Nature Agency, Ministry of Environment
SÁ¸holtvej 6
7700 Thisted
Denmark
Tel: +45-97-977088
Fax: +45-96-185229
e-mail: lifedunes@sns.dk
Website: http://www.skovognatur.dk/foralle/projekter/klithede/english.htm

Danish Forest and Nature Agency
http://www.skovognatur.dk/Emne/Naturbeskyttelse/Naturpleje/LIFE/Afsluttede/Klithede/Restorationdune.htm

Primary Contact

Organizational Contact