SOME ASPECTS OF THE IMPORTANCE OF GENETIC DIVERSITY IN PHRAGMITES-AUSTRALIS (CAV) TRIN EX STEUDEL FOR THE DEVELOPMENT OF REED STANDS

Various sites of Phragmites australis in Germany (Uckermark and Mark B randenburg) and sites in Hungary and Denmark were investigated by PCR fingerprinting in order to determine their genetic diversity. Genetic similarities were calculated and, based on this, a cluster analysis wa s performed. The genetic similarity of reed clones around one lake ran ged from between 70 to 100%, that of clones from different lakes was c learly lower. The further apart the clones were situated from each oth er, the less similar they were. At a wetland site near the shore a sud den colonisation by several new Phragmites clones was observed. This s ite was located in front of a well established genetically almost homo genous stand within the eulittoral. All the results are discussed in c onnection with a proposed model of establishment and development of wa ter reed stands: colonization, selection of best adapted clones by com petition and the stability of stands.