Date of Graduation
1999
Document Type
Thesis
Degree Type
MS
Committee Chair
James B. McGraw
Abstract
Harvesting of wild American ginseng (Panax quinquefolius L.) has lowered natural population sizes. Accurate assessment of extinction risks necessitates an understanding of the demographic consequences of small populations. I experimentally tested for reproductive limitation of plants in small populations (a form of the Allee effect). I found that fruit production per plant significantly declines in small populations, suggesting mate-limitation of seed set despite the ability of ginseng to self-pollinate. A detailed breeding system study was then carried out, demonstrating that both selfing and outcrossing contribute to seed production. A third study examined the spatial extent of pollen flow in an attempt to determine how to define the spatial boundaries of populations (and hence, their size). Site to site variation in pollen movement was evident, however pollen flow was observed at a distance of 50 m from the central population. Hence, natural populations may be larger than they appear from rapid ground surveys.
Recommended Citation
Hackney, Erin Elizabeth, "The effects of small population size, breeding system, and gene flow on fruit and seed production in American ginseng (Panax quinquefolius L., Araliaceae)." (1999). Graduate Theses, Dissertations, and Problem Reports. 10497.
https://researchrepository.wvu.edu/etd/10497