PROJECT DESCRIPTION
BACKGROUND
At the end of the last Ice Age, about 10 000 years ago, an extensive area of peat bogs was created along what is now the Drenthe-Friesland border. For centuries, peat was used for heating on a small scale, but large-scale land clearance for agriculture between 1600 and 1900 fundamentally changed the character of the region. All that was left of this once huge peat resource was the Fochterloërveen (3 000 ha) and a few smaller cores. Even here, the peat degraded and turned into earth after the peat bog was drained for tree-planting and farming (of buckwheat varieties). The result was a monotonous expanse of Molinia grasses. Only in the highest core area was the peat still intact, complete with the vegetation associated with raised bogs. Sufficient peat moss (sphagnum) still grew here to sustain peat formation: it therefore provided a core area from which the entire Fochterloërveen raised bog could be restored. Apart from agricultural activities, this is a lonely, isolated region (the Fochterloërveen itself is surrounded by penal institutes), which in principle made the work of restoration easier. In 1965, the drainage ditches were sealed off and extraneous water was kept out. The task of restoration itself began in the 1980s, with the building of low dykes, creating isolated compartments on the bog surface. The aim was to manage the water levels in each compartment in such a way that peat moss could grow there again. The compartments proved to be too big, however, and the differences in their height above sea level has meant that some are too dry and others too wet.
OBJECTIVES
This LIFE project was based on a "Hydrologische Inrichtingsplan voor Hoogveenregeneratie" (Hydrological Raised Bog Restoration Plan). Raised bogs are fed by rainwater, of which there is a sufficient volume locally. The aim was to prevent rain water from flowing off the raised bog too quickly and to stimulate natural peat formation. Making the compartments smaller, beginning with the highest ones in the middle of the area and then working outwards to the periphery, was to give the bog restoration a helping hand. At the same time, a buffer zone of more than 400 ha was to be created around the bog with national funds. The LIFE project itself is a unique experiment in restoration and an example of Dutch hydraulic engineering. The task of cutting peat with which to cover the sheet piling for the compartments needed to be done with care, so as not to cut such deep holes that peat formation becomes impossible. The restoration work also had to take account of possible flooding as a result of heavy rain, water seepage where the (excessively) thin peat lies on a sandy ridge, the swelling of peat when it gets wet, and access for visitors. Its precise, phased approach had the potential to make the project a model for peat bog restoration elsewhere in Europe.
RESULTS
The core results achieved by this LIFE-Nature project were: (a) the construction of compartments subdividing the bog by means of peat-covered dykes and dams; (b) the inundation of these compartments to stimulate Sphagnum growth, to initiate peat-production and to kill the purple moor grass (Molinia); (c) the control of the water levels afterwards in function of the monitoring of the bog restoration. The works were carried out from the central part of the bog outwards – the core and highest part of the raised bog was done first, and then the increasingly lower-lying zones located concentrically around this core. The dykes and dams were carried out as planned. Altogether 24.5 km of dykes and 39 dams were built. Works were also carried out to adapt the local traffic infrastructure to the new situation created by the rehumidification project: - Fochteloërveenweg: replacement of an asphalted road by a narrower road with a surface of bricks on a pebble substrate; - Bonghaar cycle track: replacement of asphalted cycle track by a gravel track on top of one of the dykes acting as border of a compartment; an observation platform and a short boardwalk leading to it were built beside this cycle track. Wildlife screens and passages to guide reptiles (snakes) and amphibians to underpasses below the Fochteloërveenweg and the Bonghaar cycle track, were built. A first set associated with the Fochteloerveenweg was done in 2001 and were the first wildlife passages specifically designed for snakes in the Netherlands. Monitoring: 105 permanent plots and 7 transects for vegetation monitoring were set up. For hydrological monitoring, the project established a network of 23 gauges for surface water, 17 for groundwater and 4 lysimeters for water quality. The first phase of hydrological (abiotic) and vegetation monitoring (1999-2002) was charged to LIFE, but would be continued for another 6 years, funded by Dutch national funds. Fauna is monitored by local volunteers. Information and communication: - 5 public meetings in surrounding villages, plus bilateral meetings with stakeholders (landowners, tourism boards, horse riding clubs); - participation in two village festivals and a sports rally (with theatre, floats, decoration); - production of a brochure (15,000 copies) and an exhibition; - erection of 7 information panels; - elaboration of an educational nature trail and a package for schools; - excursions for locals, visitors, press and stakeholders. Conservation benefit: The 3,000 ha Fochteloerveen is one of the largest raised bogs in the Netherlands. At the end of the LIFE-project, all necessary dykes have been built and inside the compartments water level can be controlled by a system of dams. Thus the hydrology of the entire raised bog can be managed and peat formation can be initiated. This is quite unusual in LIFE-Nature as peat restoration projects generally focus on drainage-ditch blocking rather than address the entire peat body. A method was developed during the project to measure the rate at which peat absorbs water after rehumidification and swells. This yielded data which indicates that the comprehensive raised-bog restoration has been successful: - the new dyke compartments allow a better control of the water levels: seepage no longer occurs to an extent that the bog surface desiccates; maximum annual water level fluctuation is 20-30 cm; - the water quality is good (pH 4 and low in carbonates and nutrients): so the water chemistry is suitable to restart Sphagnum growth; - natural methane production promotes floating of the free peat layer, so that Sphagna have a substrate to grow from; - purple-moor grass (Molinia caerulea) decreased and water peatmoss (Sphagnum cuspidatum) increased; - the characteristic raised-bog hummock-forming peat mosses increased (S. magellanicum, S. rubellum and S. fuscum); - the population of Coenonympha tullia, a threatened butterfly of which the site hosts the largest of the remaining Dutch populations, and the population of dragonflies of raised bogs are apparently increasing in size; - the wildlife passages built during LIFE are certainly a success: in 2002 only one snake was killed by traffic, compared to up to 100 annually before. The improvement of the nature area already resulted in the increase of a number of Annex I bird species. Crane (Grus grus) successfully bred in 2001 for the first time in the Netherlands since the Middle Ages and again in 2002 and 2003 (2 pairs in that year, with 3 chicks). Since 2001 two short-toed eagles (Circaëtus gallicus) were staging for a long time each year in the restored bog. Geese had, by the end of the project, started using the areas of open water as resting places during migration – this will be carefully monitored to see if the geese cause any eutrophication problem. Innovation and demonstration: The project learned as it went along. The dykes around the compartments were made of pilings covered by peat, which was needed to protect the wood. The type of wood best suited for the pilings turned out to be French oak, but this did cause some technical difficulties in construction which had to be overcome. At a later stage PLATO-treated pine wood (developed by a LIFE Environment project) was used. It proved so satisfactory that it was adopted for the subsequent LIFE-Nature Korenburgerveen project. Techniques to install the pilings also evolved during the project as well as the way the cut sods of peat were deployed over the dykes to reduce the potential for wind and wave action caused by areas of open water adjoining the dykes. Rubber caterpillar treads were installed on machinery because this caused less damage – steel treads turned out to be too damaging for soil and vegetation. Using the areas where peat sods were cut or where dykes would be built, as tracks, also helped to limit damage. Experience with the first wildlife screens and passages led to improvements in design of the next ones. The project management also discovered techniques to save costs and get advantageous prices from subcontractors. The experience gained in this project as well as the monitoring results are already being used in the LIFE project Korenburgerveen and also in mire projects funded by national progammes (e.g. Haaksbergerveen). Through its contribution to the adaptation of cycle tracks, observation platforms and information panels, it helped create infrastructure for nature-based tourism. Tourism and recreation are already very important for the local economy and that is why the beneficiary held bilateral talks with the tourism boards. Nature education and public awareness work helped raise the profile of the raised bog and the project among the local population – with good results, local pride in the site increased during the project, as evidenced by two village festivals and a sports rally (where there was theatre, floats, and street decoration referring to the raised bog). A number of important flanking initiatives took place in parallel to this project: - a strategic plan by the provincial authorities to enlarge the nature area around Fochterloerveen to ca 4.500 ha; anticipating this project, Natuurmonumenten already bought over 300 ha of the Fochteloërveen buffer zone; - a large-scale hydrological assessment of the Fochteloërveen and surroundings, with objective to keep water as long as possible in the buffer zone. After LIFE: For the rehumidified raised bog itself, the investment work has been done – continuation implies monitoring developments (hydrological and biological), managing water levels in function of these developments and where necessary repairing or upgrading dams and dykes. Provisions to keep up this recurring management were made (a permanent site manager was employed by the beneficiary, national funds were identified for the monitoring after LIFE)