Data from: Patterns of genetic diversity reveal multiple introductions and recurrent founder effects during range expansion in invasive populations of Geranium carolinianum (Geraniaceae)

Genetic diversity, and thus the adaptive potential of invasive
populations, is largely based on three factors: patterns of genetic
diversity in the species' native range, the number and location of
introductions, and the number of founding individuals per introduction.
Specifically, reductions in genetic diversity ("founder
effects") should be stronger for species with low within-population
diversity in their native range and few introductions of few individuals
to the invasive range. We test these predictions with Geranium
carolinianum, a winter annual herb native to North America and invasive in
China. We measure the extent of founder effects using allozymes and
microsatellites, and ask whether this is consistent with its colonization
history and patterns of diversity in the native range. In the native
range, genetic diversity is higher and structure is lower than expected
based on life-history traits. In China, our results provide evidence for
multiple introductions near Nanjing, Jiangsu province, with subsequent
range expansion to the west and south. Patterns of genetic diversity
across China reveal weak founder effects that are driven largely by low-
diversity populations at the expansion front, away from the introduction
location. This suggests that reduced diversity in China has resulted from
successive founder events during range expansion, and that the loss of
genetic diversity in the Nanjing area was mitigated by multiple
introductions from diverse source populations. This has implications for
the future of G. carolinianum in China, as continued gene flow among
populations should eventually increase genetic diversity within the more
recently founded populations.