Spatial genetic structure and clonal diversity of Anemone nemorosa in late successional deciduous woodlands of Central Europe

Abstract

1. We tested whether established populations in similar environmental conditions exhibit similar or varying spatial genetic structures by comparing populations of the long-lived species Anemone nemorosa from a number of late successional deciduous woodlands in Central Europe. We discuss the ways in which genetic structure may have been shaped by clonal growth and sexual reproduction. 2. A standardized sampling strategy was used to collect 30 ramets from each of 20 populations. Genotypes of the samples were determined by allozyme electrophoresis and analysed assuming that A. nemorosa shows tetraploid-tetrasomic inheritance. 3. 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 examples occurring more than once. Differences between observed and expected heterozygosities within populations were generally small to moderate. Fixation indices (mean of over 14 loci) in the populations ranged between 0.08 and 0.56 (grand mean = 0.21) confirming reports that the breeding system in A. nemorosa is predominantly outcrossing or mixed-mating. 4. Limited historic gene flow among populations (Nm = 0.62) was reflected by high population differentiation (G(ST) = 0.29), low genetic identities among populations and a non-significant correlation between these identities and geographical distances. 5. 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 were genetically more closely related than to more distant samples, but similarity of genotypes decreased only slightly with further increase in distance. 6. 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.