Genet age in marginal populations of two clonal Carex species in the Siberian Arctic

During a Swedish-Russian expedition to northern Siberia 1994, we sampled two marginal populations of two Carex species at two high arctic sites (C. stans Drej. on Faddeyevsky Island and C. ensifolia V. Krecz ssp. arctisibirica Jurtz. at north-eastern Taymyr Peninsula), both north of previously documented localities in that areas for the two species. These populations were composed of a few distinct patches of ramet colonies, some of them shaped like fairy rings with dead centres. We measured the size of all colonies and collected samples for detailed morphometric analyses of rhizome growth. By using RAPD (random amplified polymorphic DNA) analysis we established that the largest colony at each site consisted of a single genet, based on 41 polymorphic bands amplified with three primers. Pooled samples from each of two additional colonies of C. stans on Faddeyevsky Island were analysed and showed that clones of the same species at the same site were relatively dissimilar (Dice's similarity index 0.26-0.43). We then assumed that each ramet colony represented a single genet. Based on the morphometric data, we developed a deterministic growth model that simulates the clonal growth of these species and enabled estimates of the time since establishment of the genets. The estimated age of the five C. stans clones varied from 17 to 154 yr and the age of the two C. ensifolia ssp. arctisibirica clones was well over 3000 yr.