Population Structure of the Rare, Long-Lived Perennial Gentiana pneumonanthe in Relation to Vegetation and Management in the Netherlands

After analysis of population age-state spectra of Gentiana pneumonanthe in a variety of vegetation types, three different population types could be distinguished: (a) «invasive» or «dynamic» populations, characterized by high densities of seedlings and juveniles relative to the adult age states, (b) «normal» or «stable» populations with adult age states prevailing, but with low densities of seedlings and juveniles, and (c) «regressive» or «senile» populations, consisting only of adult flowering and adult vegetative individuals. The structure of the surrounding vegetation appears to be very important in determining the population structure of the marsh gentian. In particular the percentage of bare soil surface and the cover of the litter layer explain most of the variation in the density and proportion of different age states in the populations