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 tw o marginal populations of two Carex species at two high arctic sites (C. st uns Drej. on Faddeyevsky Island and C. ensifolia V. Krecz ssp, arctisibiric a Jurtz. at north-eastern Taymyr Peninsula), both north of previously docum ented localities in that areas for the two species. These populations were composed of a few distinct patches of ramet colonies, some of them shaped l ike 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 p olymorphic bands amplified with three primers. Fouled samples from each of two additional colonies of C. stuns on Faddeyevsky Island were analysed and showed that clones of the same species at the same site were relatively di ssimilar (Dice's similarity index 0.26-0.43). We then assumed that each ram et colony represented a single genet. Based on the morphometric data, we de veloped a deterministic growth model that simulates the clonal growth of th ese species and enabled estimates of the time since establishment of the ge nets. The estimated age of the five C. stans clones varied from 17 to 154 y r and the age of the two C. ensifolia ssp. arctisibirica clones was well ov er 3000 yr.