Dissertation Research: Dispersal, Breeding Patterns, and Genetic Structure of an Epiphytic Orchid

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Hamrick0104598In plants, gene movement is mediated either via pollen or seeds. In most flowering plants, pollen can potentially travel much greater distances than seeds. Orchids, however, are capable of considerable long-distance seed dispersal while pollen flow is limited to the range of pollinator movement. What is the relative contribution of pollen and seed dispersal to overall partitioning of genetic variation? How much gene movement occurs in disturbed habitats and what is the spatial scale of that movement? To address these questions, the distribution of genetic diversity in the neotropical, epiphytic orchid, Laelia rubescens, will be examined at multiple spatial scales using biparentally inherited nuclear markers (allozymes) and maternally inherited chloroplast sequence markers. Genetic diversity is crucial for the long-tern survival of species, particularly in fragmented and disturbed landscapes which are becoming increasingly ubiquitous. It increases the likelihood that a species can survive environmental fluctuations and natural catastrophes that invariably occur over time. By better understanding how pollen and seed dispersal impact the distribution of genetic diversity in this orchid, insights will be gained into how forest fragmentation influences genetic viability and how species with long-distance seed dispersal capabilities may preserve genetic variation and thereby facilitate their long-term survival in highly disturbed habitats.