Figure 2.

Sample sizes and genetic diversity estimates by site for (a) B. tricaudatus and (b) B. bicaudatus. Site IDs indicate drainage (P, B or S) followed by elevation in meters. Plots of observed heterozygosity (H_o) and gene diversity (H_s) represent the distribution of heterozygosity for each site. Plots of pairwise F_ST represent the distribution of pairwise relationships for a given site with all other sites. Pairwise F_ST values were not computed for sites with low sample numbers (n⩽8). In general, B. bicaudatus populations show reduced genetic diversity and elevated pairwise F_ST, reflecting the combined effects of isolation, drift and local adaptation.