text: The five researchers investigated clonal diversity, as well as the size structure and longevity of genets (a group of genetically identical individuals), in populations of four arctic-alpine plants ( Carex curvula , Dryas octopetala , Salix herbacea and Vaccinium uliginosum ), in order to evaluate "their persistence under past climatic oscillations." This they did by determining the size and number of genets via an analysis of amplified fragment length polymorphisms and a standardized sampling design in several European arctic-alpine populations, where these species dominate the vegetation, while "genet age was estimated by dividing the size by the annual horizontal size increment from in situ growth measurements."