Orchid colonization: multiple parallel dispersal events and mosaic genetic structure in Dactylorhiza majalis ssp. lapponica on the Baltic island of Gotland.
Background and Aims The island of Gotland in the Baltic Sea had no contact with surrounding continental areas since the withdrawal of the Weichselian ice sheet at ca 17 ka BP. Plants present on Gotland must have arrived by long distance dispersal, so populations are expected to exhibit reduced levels of genetic diversity compared with surrounding mainlands. However, orchids have very small seeds, Background and AimsThe island of Gotland in the Baltic Sea has had no contact with surrounding continental areas since the withdrawal of the Weichselian ice sheet at approx. 17 ka BP. Plants present on Gotland must have arrived by long-distance dispersal, so populations are expected to exhibit reduced levels of genetic diversity compared with populations on surrounding mainlands. However, orchids