Fig 1.
Geographical location, environmental niche model and distance-based relationship tree of sampled sites for Castanospermum australe.
The map indicates the location of each sampled site within NNSW and AWT (each site represents eight individuals), with a different colour to represent each catchment, and pink squares to represent the herbarium records to display overall species’ distribution. Shading within the map represents a relative scale of environmental suitability for the study species. A distance tree shows the relative genetic distances between catchments (branch lengths according to indicated scale of nucleotide substitutions per base pair, node values indicate branch support), and identifies sites to each catchment (represented by the colour used in the map). The objective of the tree is not to estimate branching topology or deeper relationships among its branches, but to visually represent diversity within the focal lineage.
Fig 2.
Map of northern NSW (NNSW) showing sampled sites, relevant river catchments, and Aboriginal Songline.
The main study area (NNSW) showing: shaded elevation (darker equals higher); the distribution of Castanospermum australe (verified herbarium records, pink squares); the location of the genomic samples across the three main catchments (locations are colour-coded as per Fig 1); publicly listed Aboriginal places of importance; and the Nguthungulli Songline. The Songline traverses the main ridge of the Nightcap, Border and McPherson ranges, which traverse the top of the three main NNSW catchments across which C. australe was sampled for this study.
Table 1.
Castanospermum australe sampling sites.
Sites are arranged in a latitudinal pattern, starting with the comparative northern sites (AWT) followed by the main study sites (NNSW). Names (and abbreviations), location details, elevation and distance from the coast are listed.
Table 2.
Summary of cpDNA and nrDNA genomic data for Castanospermum australe.
Population-level diversity for chloroplast and nuclear ribosomal DNA across all sample sites, and regional between-catchment genomic distances. Overall, diversity and divergence are higher in the comparative northern populations (AWT), than across the main study sites in northern NSW.