Hydrology and restoration of wet heathland and fen meadow communities, 2000

“Until the beginning of the twentieth century wet heathlands were widespread in the Pleistocene
landscape of The Netherlands (de Smidt 1977). Most wet heathlands have been reclaimed
since the introduction ofartificial fertilizers, but remnants have been protected as nature
reserves. These nature reserves are ofinterest for their botanical and zoological richness,
but also for the preservation of archaeological objects and old semi-natural landscapes. Despite
their protection as nature reserves, wet heathland ecosystems have deteriorated during
the last decades, mainly as a consequence ofacidification, eutrophication and changes in the
hydrology, not only in The Netherlands, but also elsewhere (van Leeuwen 1954; Westhoff
1979; Dierssen 1981; Heil & Diemont 1983; Arts et al. 1990; Buck-Sorlin 1993). Due to
these changes in environmental conditions, the species-rich, low-productive and fine-grained
vegetation ofwet heathlands has been replaced by species-poor, highly productive and more
homogeneous, coarse-grained, vegetation, due to which characteristic plant communities and
species ofwet heathlands have become rare. Thus, biodiversity has decreased. During the last
decade several attempts have been undertaken to stop further deterioration and to restore wet
heathlands, even on former agricultural fields. It is generally recognised that such attempts
may only be successful, when the required site conditions can be restored (Wheeler 1995).
The site conditions of wet ecosystems, i.e. base status, nutrient status and groundwater regime,
are to a large extent dependent on hydrological processes (Wheeler 1995; Wheeler &
Shaw 1995). This thesis focuses on the restoration prospects of wet heathland ecosystems
within the context oftheir hydrological functioning.”

(Citaat: Jansen, A.J.M. – Hydrology and restoration of wet heathland and fen meadow communities, 2000)