Frequencies and effects of hybridisation between two arctic plant species: Pyrola grandiflora and P. minor
Thure P. Hauser
dep. Agriculture & Ecology, Copenhagen University
In the Arctic, hybridization, polyploidisation and introgression have been important for the evolution of the flora. With the predicted and ongoing change of climate, there will be an increased influx of plants from warmer parts of Eurasia and America. The fate of these newcomers, and of the resident species, will depend on the competitive and reproductive interactions between them.
Two species of Pyrola (Danish: vintergrøn) grow in Greenland. Both have a circumpolar distribution, but P. minor has a more southern distribution including Europe. At Disko Island on the west coast, P. minor has its northern limit, and hybridizes with P. grandiflora. In a project financed by the Carlsberg Foundation, we study the dynamics of hybridization between the two species to evaluate how hybridization may affect their distributions locally and regionally. Last summer we collected material to test if hybridization has led to integration of genetic material of one species into the other (introgression) by characterizing the genetic and morphological composition of local populations of the species. To test how easy it is for the two species to hybridize, we further did controlled pollinations between the species and hybrids and evaluated to what extent seeds are produced. In the coming summer, we will survey how often plants are actually pollinated, how well foreign pollen grows in the styles, and how successful hybrids grows in the habitats of the parental species.
