Molecular Ecology and Evolution
Theim, Terra J. , Givnish, Thomas J. .
Gene flow and fecundity in tropical forest understory Psychotria .
FECUNDITY and density of reproductive individuals of a plant species are important factors affecting pollinator behavior, seed disperser behavior, seedling establishment, and spatial genetic structure. Even though understory trees and shrubs comprise the majority of species in moist tropical forests, studies of their genetic structure are almost nonexistent. I quantified genetic structure and apparent gene dispersal using AFLP markers in four understory species of Psychotria (Rubiaceae: Psychotrieae) in Panamanian rainforests. Mantel tests showed significant genetic structure at fine geographic scales ( < 512-1024 m) in all four species. RMS gene dispersal also operated over remarkably short distances (ca.10-50 m), smaller than any woody, animal-dispersed taxa studied to date. Neighborhood size varied from 10 to 41 individuals. Genetic differentiation at small spatial scales is consistent with the hypothesis that the seeds of fleshy-fruited trees in tropical understories should be dispersed relatively short distances by sedentary forest-interior birds. Relative fruiting rates and absolute density of fruiting individuals were very tightly correlated with estimated gene dispersal, consistent with models based on pollen dilution and density-dependent mortality.
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1 - University of Wisconsin Madison, Department of Botany, Birge Hall, 430 Lincoln Drive, Madison, Wisconsin, 53706-1381, USA
population genetic structure
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 31st, 2006
Time: 2:00 PM