Genetic variation and clonal diversity in four clonal sedges (Carex) alongthe Arctic coast of Eurasia

We studied the structure of genetic variation (at both ramet- and genet-lev el) and clonal diversity within and among populations in the four closely r elated arctic clonal sedges Carex bigelowii, C. ensifolia, C. lugens and C. starts by use of allozyme markers. Compared to other sedges and arctic pla nts, the studied taxa all had high levels of genetic variation, both within populations and taxa. These taxa contained most of the total gene diversit y (H-T) within populations and a small part of the diversity among populati ons (G(ST) ranged 0.05-0.43). Carex bigelowii had genetic variation (H-S = 0.173, mean for populations) at a comparable level to other outbreeding arc tic plants and to other widespread, rhizomatous and mainly outbreeding Care x species. In contrast, C. ensifolia (H-S = 0.335), C. lugens (H-S = 0.339) and C. stans (H-S = 0.294) had within-population variations that were high er than in most other studied Carex species and for arctic plants in genera l. Genetic variation was not related to any tested environmental variable, but it was lower in areas deglaciated only 10 000 years BP compared to area s deglaciated 60 000 years BP or not glaciated at all during the Weichselia n. All the populations were multiclonal, except for two populations of C. s tarts that were monoclonal. In contrast to genetic variation, clonal divers ity decreased with latitude and did not differ between areas with different times of deglaciation. In accordance with previous studies, C. bigelowii a nd C. lugens were found to be outbreeding, while C. ensifolia and C. stans had mixed mating systems.