THE RESTORATION OF SPECIES-RICH HEATHLAND COMMUNITIES IN THE NETHERLANDS

The wet heathland communities of the Ericetum tetralicis and the Cirsi o-Molinietum have declined in the Netherlands due to acidification, eu trophication and lowering of the water table. To investigate the prosp ects of restoration of both communities, the effects of sod cutting an d hydrological measures on vegetation and soil chemistry were studied in two nature reserves where these plant communities occurred decades ago. The combination of sod cutting and hydrological measures has rest ored several rare,groundwater dependent heathland communities. Sod cut ting has restored the Ericetum tetralicis, but not the Cirsio-Moliniet um. This might be due to the absence of viable seeds of characteristic species of the Cirsio-Molinietum and/or the absence of optimal site c onditions, especially high phosphorus concentrations in the top soil. The high phosphorus concentrations might be a consequence of high mine ralization rates and/or prolonged inundation with iron-poor water and the decreased flux of iron-rich groundwater into the topsoil. Restorat ion of the Cirsio-Molinietum only seems possible when sod cutting is c arried out together with hydrological measures that counter prolonged inundation and reinforce the discharge of base and iron-rich groundwat er.