Data from: Habitat type and dispersal mode underlie the capacity for plant migration across an intermittent seaway

Background and Aims Investigating species distributions across geographic barriers is a commonly utilized method in biogeography to help understand the functional traits that allow plants to successfully disperse. Here the biogeographic pattern analysis approach is extended by using chloroplast DNA whole genome ‘mining’ to examine the functional traits that have impacted the dispersal of widespread temperate forest species across an intermittent seaway, the 200 km wide Bass Strait of southeastern Australia. Methods Multiple, co-distributed species of both dry and wet-forests were sampled from five regions on either side of the Strait to obtain insights into past dispersal of these biomes via seed. Using a Next Generation Sequencing-based pooled-seq method the sharing of Single Nucleotide Polymorphisms (SNPs) was estimated between all five regions in the chloroplast genome.
Key Results A total of 3,335 SNPs were detected in 20 species. SNP sharing patterns between regions provided evidence for significant seed-mediated gene flow across the study area, including across Bass Strait. A higher proportion of shared SNPs in dry-forest species, especially those dispersed by birds, compared to wet-forest species suggests that dry-forest species have undergone greater seed-mediated gene flow across the study region during past climatic oscillations and sea level changes associated with the interglacial/ glacial cycles. Conclusions This finding is consistent with a greater propensity for long distance dispersal for species of open habitats and proxy evidence that expansive areas of dry vegetation occurred during times of exposure of Bass Strait during glacials. Overall, this study provides novel genetic evidence that habitat type and its interaction with dispersal traits are major influences on dispersal of plants.