Amplified fragment length polymorphism analysis reveals high genetic variation in the Ouachita Mountain endemic Carex latebracteata (Cyperaceae)

Abstract

Species with limited geographic ranges are often of conservation concern because they may possess low levels of genetic variability and thus have a reduced ability to respond to stochastic events. As a consequence, an important conservation strategy is to maximize a species’ adaptive potential by preserving natural levels of genetic variation. With this goal in mind, we assessed genetic variation within and among six populations of the Ouachita Mountain endemic Carex latebracteata Waterfall using 653 amplified fragment length polymorphism (AFLP) loci. Indices of genetic variation [% polymorphic loci, expected heterozygosity (HE), population differentiation (ΦPT)] were most consistent with an outcrossing or mixed mating system despite an inflorescence morphology that seems conducive to self-pollination. An analysis of molecular variance (AMOVA) showed that >80% of the variation occurred within populations, suggesting high levels of gene flow. The close geographic proximity of most populations, which are often adjacent to streams, may facilitate long-distance seed dispersal and help to maintain high intra-population genetic variation. Conservation strategies focused on maintaining the ecological integrity of rivers and streams, and the provision of naturally vegetated buffers would likely assist in the conservation of this and other Ouachita Mountain endemics.