Habitat restoration in Landschap De Liereman

PROJECT DESCRIPTION

BACKGROUND

De Liereman is a complex area of habitats in Flanders laid out in a mosaic pattern. It includes wet depressions and steep continental dunes. The ecological gradients between sandy, loamy and peaty soils and the associated vegetation communities make this an outstanding landscape. After the deforestation of the Middle Ages, heathland developed in combination with small-scale grasslands and arable fields within a context of low intensity farming.

However, when the market for pine increased in the 19th century - timber was urgently needed for the shafts in the coal mines - the depressions were drained and the dunes were afforested with pine to better exploit the land. In the 20th century, agricultural intensification further affected the heathlands and semi-natural grassland, which only survived as relicts inside nature reserves. Most of the oligotrophic lakes disappeared or were turned into fishponds. Small wet heathlands, mire vegetations - small raised bogs and Cladium mariscus vegetations - and brook forests remained, but suffered from desiccation and increased fertilization. The former important Nardetalia grasslands only survived as tiny relicts along road verges.

Thus, by the end of the 20th century, the Liereman had lost most of its conservation value to habitat fragmentation, conifer plantations, changes in the natural hydrology and lack of appropriate land use. The project beneficiary had been making efforts since the early 1980s to restore, protect and manage parts of the Liereman, but larger-scale efforts were needed.

OBJECTIVES

The Liereman project set out to restore the natural values of the De Liereman complex of habitats - from dry heathland on the hills to oligotrophic ponds in the bottom of the valleys - through a large-scale coordinated programme of action.

The project sought to deliver a comprehensive management plan to reduce habitat fragmentation and start restoration works. Large conifer plantations would be cleared and a number of cottages removed from strategic locations to enable the natural redevelopment of heath. Locally, cleared areas would be sod-cut to restore the humid-depression fen vegetations of wet heath and, on the slopes, the rare Nardetalia vegetations. Filled and drained oligotrophic ponds would be restored.

To support and enable these actions, the project foresaw the purchase of 132 ha of land. The aim was that this initial investment should enable the beneficiary to start the long-term sustainable management of the site, including controlling visitor access to the more fragile areas.

RESULTS

The project succeeded in purchasing and restoring key areas of the De Liereman habitat. It engaged well with local stakeholders to deliver a coherent management plan that should enable ongoing preservation of the target heathland habitats into the future.

The project team started by conducting a detailed hydrological study of the project sites. This involved collation of existing data and collection of additional data by means of small-diameter observation wells (piezometers). They modelled the geo-hydrology - infiltration areas, seepage areas and water flows - and applied the model to test five different possible management scenarios for restoring the habitat.

The project also developed a concept of sustainable recreational land-use and conducted soil analyses. The studies helped inform negotiations with authorities and stakeholders on the agreement of an integral management plan based on relocating the Lieremansloop - the main watercourse crossing the site containing eutrophic water leaching from farmland.

Based on the findings, the beneficiary purchased over 143 ha of land - mainly pine plantations or agricultural land - for habitat restoration. This exceeded the target of 132 ha and helped incorporate strategic sites and reduce fragmentation. The implementation of the management plan led to the following habitat restoration actions:

Removal of trees and the litter layer and sod cutting over 44.55 ha;

Removal of invasive black cherry trees (Prunus serotina), local deep mowing and sod cutting over 52.6 ha;

Sod cutting over 57.17 ha;

Removal of the topsoil layer or intensive mowing and grazing to reduce the dominance of velvet grass (Holcus lanatus) over 21.61 ha;

Digging of two retention basins to reduce the frequency of flooding of the nutrient rich rivers;

Relocation of the Lintloop by construction of a dam and dredging of a deeper creek;

Restoration of five oligotrophic ponds, including removal of surrounding exotic conifers and bank repairs;

Thirty-four cottages were demolished and removed in co-operation with a social employment project;

For the ongoing management of the mosaic of habitats - including continental dunes, heathland and Nardus grassland - the project introduced extensive grazing over 131.26 ha, intensive mowing over 82.56 ha and small-scale mowing over 10.26 ha. Tree saplings were removed from 15.35 ha to control reforestation. The success of the management actions was shown by the return of important fauna and flora, including the natterjack toad (Epidalea calamita, formerly Bufo calamita), European nightjar (Caprimulgus europaeus), Drosera sp. and Ranunculus ololeucos.

New hiking trails were constructed and information on the area provided to visitors to encourage ongoing engagement from local people. The project has led to the Flemish Region agreeing to conduct a complementary study and nature project to deviate more creeks and further the management and conservation of the project area.

Further information on the project can be found in the project's layman report (see "Read more" section).