5 | CONCLUSIONS
This study was unusual in combining the statistical power provided by
over 1300 loci with the spatiotemporal coverage provided by sampling
over 1400 individuals across space, time, and life stage. The finding of
near genetic uniformity over large distances is an expected consequence
of a life history that facilitates dispersal. Where genetic
differentiation was detected among locations or among years, estimates
of FST were on the order of 0.0001, below the
detection limits of most previous studies. We did not determine the
causes of these slight deviations from spatial and temporal homogeneity,
but spatial variation was not related to distance and sweepstakes
reproductive success does not appear to have been the cause of temporal
variation. Gene flow from distant populations, selection, and
conventional genetic drift remain as possible explanations. In a
forthcoming paper, we will examine spatiotemporal patterns of variation
at individual loci in relation to environmental variation and consider
the possible role of natural selection.