We tested whether established populations in similar environmental conditions exhibit similar or varying spatial genetic structures by comparing populations of the long-lived, early-flowering plant species Anemone nemorosa L. in late successional deciduous woodlands of Central Europe. A standardized sampling strategy was used to collect thirty ramets from each of 20 populations. Genotypes of the samples were determined by allozyme electrophoresis. Genetic variation and clonal diversity were high compared with other clonal species. Most (95 %) of the sampled ramets had unique multilocus genotypes with only 22 multilocus genotypes occurring more than once. No recurring multilocus genotype occurred in more than one population. Fixation indices (mean over 14 loci) in the populations ranged between 0.08 and 0.56 (grand mean = 0.21) confirming that the breeding system in A. nemorosa is predominantly outcrossing or mixed-mating. Limited gene flow among populations (Nm = 0.62) was reflected by high population differentiation (GST = 0.29) and low genetic identities among populations. A non-significant correlation between these identities and geographic distances was detected (Mantel test). Spatial autocorrelation (Moran's I) showed no significant differences in genetic structures between populations under similar environmental conditions. Samples taken less than 0.5 m apart from each other were genetically more closely related than to more distant samples, but similarity of genotypes only decreased slightly with further increase in distance. The high levels of genetic variation found in populations of A. nemorosa are probably due to repeated seedling recruitment and the outcrossing or mixed-mating breeding system, whereas vegetative propagation and short-distance seed dispersal may contribute to the positive genetic autocorrelation observed at a small spatial scale.

Key words: allozymes, Anemone nemorosa, clonal size, Ranunculaceae, repeated seedling recruitment, spatial autocorrelation