Low productivity in wetlands is maintained by a relatively low nutrient availability. The vegetation of fen is moderately species-rich in plant species and rich in bryophytes. The plant communities frequently occurring in this type of environment are alliance of Caricion davallianae, Caricion nigrae, Junco-molinion and Eu-Molinion (Grootjans & Van Diggelen 1995). Fen may vary in heterogeneity and relative contribution of abiotic and biotic factors. Drainage, fertilization and liming in agricultural zones affected the surrounding area, by changing the local or regional hydrology and nutrient inputs in the environment. Caricion davallianae communities may be found on relatively nutrient poor and calcium-rich peat soils. But this community has been disturbed by a few fast-growing species (in “het Buitengoor” by Molinia caerulea and Myrica gale) causing less species richness.Our studies contributes to knowledge on restoration of rich fen where most important factors regulating the sites conditions are:-Water levels and quality-Nutrient availability (depending on biotic and abiotic factors)-Soil structure and qualityWe will test wish factors (biotic and abiotic) best describes the “relative” low nutrient availability for the caricion davallianae vegetation and high nutrient availability to the fast-growing species (Molinia caerulea). The experiments are performed at the plant community level and species level (Molinia caerulea, carex demissa and carex dioïca).