Fig. 7

Competing demographic scenarios of Psittacanthus schiedeanus divergence and admixture. Because three haplotype clusters are hypothesized to be associated with individuals/populations separated by habitat (BREE, SCHI, CALY) with post-glacial population expansions and potentially corresponding to post-glacial invasion types (see Results), five evolutionary scenarios were defined and tested: (a) three populations (Pop1, Pop2 and Pop3) have diverged simultaneously from an ancestral population at t1 (scenario 1, null model), which corresponded to the plant genetic groups, BREE, SCHI and CALY, respectively; (b) isolation split model 1 (scenario 2), in which Pop1 (BREE) merged with Pop2 (SCHI) at t1 and subsequently with Pop3 (CALY) at t2; (c) isolation split model 2 (scenario 3), in which Pop3 merged with Pop2 at t1, then both populations merged with Pop1 at t2; (d) isolation split model 3 (scenario 4), in which Pop3 merged with Pop1 at t1 and then both populations merged with Pop2 at t2; and (e) isolation with admixture model (scenario 5), in which Pop2 was generated by admixture of Pops 1 and 3 at t1, then Pop1 merged with Pop3 at t2. Comparison of the scenarios was implemented in the DIYABC software [92]. Habitat type abbreviations are as follows: SCHI cloud forests from San Luis Potosí to Oaxaca and Chiapas, CALY xeric vegetation in central Oaxaca, BREE tropical deciduous forests in Chiapas (Additional file 2)