Journal of Heredity Advance Access published online on May 21, 2008
Journal of Heredity, doi:10.1093/jhered/esn043
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Spatial Genetic Structure of the Southeastern North American Endemic, Ceratiola ericoides (Empetraceae)
From the Odum School of Ecology, University of Georgia, Athens, GA 30602 (Trapnell and Schmidt); and the Department of Plant Biology, University of Georgia, Athens, GA 30602 (Hamrick)
Address correspondence to Dorset W. Trapnell at the address above, or e-mail: dorset{at}plantbio.uga.edu.
Understanding the spatial distribution of genetic diversity (i.e., spatial genetic structure [SGS]) within plant populations can elucidate mechanisms of seed dispersal and patterns of recruitment that may play an important role in shaping the demography and spatial distribution of individuals in subsequent generations. Here we investigate the SGS of allozyme diversity in 2 populations of the southeastern North American endemic shrub, Ceratiola ericoides. The data suggest that the 2 populations have similar patterns of SGS at distances of 0–45 m that likely reflect the isolation by distance (IBD) model of seed dispersal. However, at distances
50 m, the pattern of SGS differs substantially between the 2 populations. Whereas one population continues to reflect the classical IBD pattern, the second population shows a marked increase in autocorrelation coefficient (r) values at 50–75 m. Furthermore, r values at these distances are as much as 33% higher than at 0–5 m where the highest r value would be predicted by IBD. A likely explanation is the differing frequencies of 2 fruit morphologies in these populations and the greater role that birds play in seed dispersal in the second population.
Corresponding Editor: David B. Wagner
Received January 12, 2008
Accepted April 22, 2008