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.