The effect of different methods of reconstruction and different seed mixtures on the restoration of botanically valuable, semi-natural, species- rich grasslands on enlarged river dikes (embankments) was studied. If during the reconstruction a strip of the species-rich vegetation is kept unaffected it functions as a source of propagules. From this intact zone species disperse to other parts of the dike and the redevelopment of the vegetation is stimulated. When it is not possible to save part of the original vegetation, the upper soil layer can be put aside as complete sods or as topsoil and can be replaced as the new topsoil after the reconstruction. In this way the redevelopment of species-rich grasslands is promoted by the reestablishment of previously occurring species out of the propagules present in the replaced top soil. The application of the original subsoil or the use of imported clay as the new toplayer prevent a quick restoration of botanically valuable, semi-natural, species-rich grasslands. Seed mixtures applied influence the development of succession. Redevelopment of former river dike grasslands is quickest if D1 LGM (i.e., standard seed mixture plus locally gathered seed mixture) is used as a seed mixture. Seed mixtures containing a considerable proportion of Lolium perenne seeds are unsuitable as the redevelopment is retarded, whereas application of locally gathered seed mixtures accelerate succession.