Dynamics of island populations of Cypripedium calceolus in the Biebrza river valley (north-east Poland)

Three Cypripedium calceolus populations were observed in the Biebrza National Park (north-east Poland) for 11 years (1989-99). The populations differed in the number of genets and ramets and in their dynamics. Differences were in the proportion of flowering ramets, number of flowers, fruiting and recruitment. Fruiting and recruitment are low in populations of Cypripedium calceolus. Fruiting is probably pollinators limited, and recruitment is limited by environmental conditions. Changes in the size of populations of this species are caused by the following processes: changes in the number of genets (their appearance and death), changes in the size of clones (growth of individuals and their disintegration, death of individual ramets), dormancy of genets, and animal pressure. (C) 2002 The Linnean Society of London.