Experimentelle Demographie von Pflanzen: Solidago altissima

The demography of the clonal perennial Solidago altissima was studied under different experimental treatments in the field. Development of clones, population flux of shoots, sexual reproduction, population dynamics of seeds, and growth and survival of seedlings and young plants were studied in detail over a period of 3 years. Mortality among established clones was low and occurred only in plots subjected to repeated mowing. The early development of a hierarchy of shoot sizes with predictable fates for given size classes points to a regulation of shoot growth by clonal integration. In contrast to vegetative growth sexual reproduction contributed very little to the maintainance of the population. Survival of seeds was low and germination under natural conditions extremely rare. Growth and survival of seedlings and young plants was positively correlated with size. Mowing had a highly significant effect on growth, survival, and reproduction of the population and this effect was further increased in an exceptionally dry year. A matrix model was constructed to quantitatively describe the dynamics of the population and analyze the effects of possible managment practices. Demographic analysis and population models can be used to solve problems posed by invading or endangered species.