Genetic Variation and Conservation Implications in Pennsylvania for the Rare and Imperiled Buffalo Nut (Cervantesiaceae; Pyrularia pubera Michaux)

Abstract

Buffalo nut (Cervantesiaceae; Pyrularia pubera Michx.) is a unique facultative hemiparasitic species that can reproduce clonally or sexually. Fragmented population stands of buffalo nut in Pennsylvania, USA, represent the northern–most range of distribution of the species. These leading–edge populations could be the originators for new stands expected to arise as climate change shifts this species' native range further north. When observing an isolated stand of buffalo nut, it is impossible to be sure if individual trees are clones of a common parental plant or the product of sexual reproduction. Our study represents the first attempt to use population genetic methodologies to determine the genetic relatedness of individual plants in fragmented stands, and to assess the genetic diversity of native buffalo nut populations in North America. Our study used microsatellite markers to compare genetic variation in samples from populations in Pennsylvania to samples collected in other populations in the northern end of its range (i.e., West Virginia, Kentucky, and Virginia). We found 1) that trees could not be located at most sites, and 2) that Pennsylvania populations are largely clonal with little genetic diversity among locations within the state (∼200 km2) relative to populations sampled in Kentucky and Virginia. We provide best practice suggestions for conservation of this species.