Data from: Revealing biogeographic patterns in genetic diversity of native and invasive plants and their association with soil community diversity in the Chinese coast

Within-species genetic diversity is shaped by multiple evolutionary forces
within the confines of geography, and has cascading effects on the
biodiversity of other taxa and levels. Invasive species are often
initially limited in genetic diversity but still respond rapidly to their
new range, possibly through ‘pre-adapted’ genotypes or multiple sources of
genetic diversity, but little is known about how their genetic structure
differs from that of native species and how it alters the genetic-species
diversity relationship. Here, we selected a widespread native species
(Phragmites australis) and its co-occurring invasive competitor (Spartina
alterniflora) as our model plant species. We investigated the genetic
structure of P. australis using two chloroplast fragments and ten nuclear
microsatellites in 13 populations along the Chinese coastal wetlands. We
discovered a distinct geographical differentiation, showing that the
northern and southern populations harbored unique genotypes. We also found
a significant increase in genetic diversity (allelic richness and expected
heterozygosity) from south to north. Combined with previous studies of S.
alterniflora, the Mantel tests revealed a significant correlation of
genetic distances between P. australis and S. alterniflora even when
controlling for geographic distance, suggesting that the invasive species
S. alterniflora might exhibit a phylogeographic pattern similar to that of
the native species to some extent. Furthermore, our results suggest that
the S. alterniflora invasion has altered the relationship between the
genetic diversity of the dominant native plant and the associated species
richness of soil nematodes. The reason for the alteration of
genetic-species diversity relationship might be that the biological
invasion weakens the environmental impact on both levels of biodiversity.
Our findings contribute to understanding the latitudinal patterns of
intraspecific genetic diversity in widespread species. This work on the
genetic diversity analysis of native species also provides significant
implications for the invasion stage and ecological consequences of
biological invasions.