Regional dynamics of Calamagrostis pseudophragmites on riverbanks in the NP Gesäuse inferred from AFLPs

Calamagrostis pseudophragmites (Poaceae) is a pioneer equestrian grass that grows on the banks of the alpine rivers and is one of the endangered species in Austria due to the increasing river regulation and the increasing number of hydropower plants. The population of C. pseudophragmites in Gesäuse National Park was studied to assess the clonal structure and role of clonal migration along the Enns, as well as the genetic structure, differentiations and mode of regional dynamics within the population. The present study suggests that sexual reproduction is prevalent in the C. pseudophragmites population and that vegetative reproduction is important at the subpopulative level. The overall genetic differentiation between subpopulations is moderate, but both Haslau subpopulations differ very well from other eastern subpopulations. Thus, there is a remarkable gene flow within the population mainly due to pollen flight. The distribution of seeds is carried out between all population groups. The population of C. pseudophragmites in the Gesäuse provides evidence of metapopulation dynamics in the sense of extinction and (re)population processes, especially in the few years since Kammerer’s study (2003). As long as the regeneration of the population is possible and the population has no major setbacks, no specific genetic threat to the survival of this species in grooms is known. Further constant monitoring and protection of the sensitive habitat of C. pseudophragmites is proposed.