Clonal diversity of populations of Calamagrostis epigejos in relation to environmental stress and habitat heterogeneity

The clonal diversity of four populations of the vegetatively propagating grass Calamagrostis epigejos was studied with isozyme markers From each population, 100 individuals were sampled within a 10 × 10 m gnd In two populations of unpolluted sites 5 and 10 clones were distinguished, respectively Higher levels of clonal diversity were found m the populations at an abandoned sewage farm (59 clones) and around a copper smelter (92 clones) The level of clonal diversity observed suggests that sexual recruitment is important for the genetic structure in this species On the unpolluted, presumably more suitable habitats, the clonal diversity was lower than on the habitats polluted with heavy metals The results are discussed in relation to environmental stress and habitat heterogeneity, with the conclusion that in the unpolluted habitats intraspecific competition results in low clonal diversity On the other hand, stressful conditions decrease the importance of competition and facilitate the coexistence of a great number of clones