The Dutch study area for Bio-SOS is located within the Natura 2000 site the Veluwe (site codes: NL9801023+ NL3009017). Although the Veluwe has a total surface of 91.200 ha, the selected sites are much smaller.
The heathland area Ginkelse and Ederheide measures approximately 1000 ha and is known for its large area covered by Calluna heath vegetation. This terrain is managed by Ministry of Defense and is also used for military exercises.
The Wekeromse Zand is an active inland sand dune area, 3 km North of the Ginkelse and Ederheide, with a total area of approximately 500 ha. About 100 ha of this area is covered by open space with active inland sand dunes. Less digital data are available for this site, but the active inland sand dunes are of European importance. Moreover, both sites are so close (3km distance) that they can be treated as one case study area in BIO-SOS. Most important pressure to the biodiversity of the above mentioned habitats are the nitrogen deposition caused by intensive agriculture in the region.
Data available for the sites:
- Digital aerial photographs (e.g. 1989, 1992, 1995, 2000, 2003, 2005, 2006, 2008)
- Hyperspectral data: AHS-160
- Landsat TM or SPOT XS
- Medium and low resolution long term time series (MERIS, MODIS, NOAA-AVHRR)
- Land use databases(LGN-1 – LGN-6)
- Digital topographic maps 1:10.000
- Historical topographic maps
- Vegetation maps en relevés
- Soil data
- Digital terrain models (AHN)
- Management database in terms of sod cutting and mowing (derived from aerial photo-interpretation period 1982-2006.
- Airborne LiDAR data is planned to be ordered.
- Wageningen University got a ground LiDAR
Ginkelse- and Ederheide
Habitat types: European dry heath (4030), Dry sand heaths with Calluna and Genista (2310), iii) 2330 Inland dunes with open Corynephorus and Agrostis grasslands.
The vegetation on the Ginkelse and Ederheide consist mainly of dry and wet heath, grassland vegetation, herbaceous and shrub vegetation, and forest. In addition, small areas with open sand can be found. The Ginkelse heide is located to the south of the main road N224 going from Ede to Arnhem, and the Eder Heide is located to the North of it. Besides its ecological values, it has also archaeological values: urn fields date back from 1100 - 500 BC. The heath vegetation has developed during the Middle Ages as part of agricultural use. For many centuries, the organic layer was removed from the surface by sod-cutting. The sods were transported to a stable, where it was mixed with the animal manure and subsequently re-used on arable land. Due to overexploitation and mismanagement, the sandy soils lost fertility and heath land and inland dune systems developed.
This practice continued until the 19th century. Starting already in the beginning of the 20th century, the Ginkelse & Ederheide was used as a military exercise terrain and intensively used. A historic milestone for the area is that it has been the landing place for paratroopers during the operation Market Garden in World War II. Heavy fighting took place in and around this area then.. During the last 30 years military use has been combined with outdoor recreation (hiking, cycling). As a result ecological processes are under pressure and this causes continuous change of the landscape. Currently, the area is managed and owned by the Ministry of Defence. The current management objectives for the area is to keep heath land vegetation (Calluna vulgaris and Erica tetralix) in its optimal condition (age differentiation) by;
- preventing grass encroachment;
- preventing natural generation of trees;
- preventing the loss of sand dunes;
- providing optimal conditions for fauna.
Especially as a result of increased nitrogen deposition the quality of the heath vegetation declined rapidly during the 1980s due to grass and shrub encroachment. Specific management was carried out to influence this process: sod-cutting, ploughing, grazing etc. Based on analysis of a time-series of aerial photographs, the management over the period 1982-2006 was reconstructed. Initially ploughing was applied on a large scale which still can be detected in the patchy structure of the heathland in especially the Ginkelse heide. At the beginning of the 1990s less intensive practices were applied such as mowing and sod cutting, however over smaller areas.
Habitat types: i) 2310 Dry sand heaths with Calluna and Genista; ii) 2330 Inland dunes with open Corynephorus and Agrostis grasslands; iii) 6230 Species-rich Nardus grasslands; iv) 9120 Atlantic acidophilous beech forests with Ilex and sometimes also Taxus in the shrub layer; v) 9190 Old acidophilous oak woods with Quercus robur on sandy plains.
The Wekeromse Zand is situated North of the Eder Heide, with a total area of 513 ha. About 100 ha are covered by open space with active inland sand dunes. The inland sand dunes are manmade due to intensive agricultural use of the heath land vegetation during the middle ages. The historic agricultural use of the area can be deduced from the presence of Celtic fields in the area which date back to the Iron Age. The active sand dunes make the Wekeromse Zand an ecologically unique landscape, almost not disappeared from Europe. In the last 200 years, those sand dunes have been partly overgrown. In 1800, the sand dunes still covered an area of around 300 ha, in 1900 around 170 ha, in 1960 around 40 ha and in 1993 only 14 ha . The Wekeromse zand is currently owned and managed by the Dutch foundation “Geldersch Landschap”. To promote natural dynamics, in 1972 en 1973 the Geldersch Landschap has cut more than 35 ha of forest to ‘give the wind its way’ and an area of open sand again could develop and expand again.
Open sand forms a very extreme biotope with large temperature differences between day and night. Often the ecosystem is very dry as the sand has a low water holding capacity. As a result only some specialized species are able to survive in these kind of systems. In the central part of the area all stages of natural succession of sand are present. Pioneer flora of the sand are Grey hair-grass (Corynephorus canescens) and sand sedge (Carex arenaria), followed by the moss polytrichum (Polytrichum piliferum). In this more stable environment, different types of lichens are able to develop. In a next succession stage, heathland vegetation is starting to develop. High quality dry heath land are present around the central sand dune area. The complete area is surrounded by conifer and mixed forests.