Contrasting diversity and demographic signals in sympatric narrow range endemic shrubs of the southwest Western Australian semi-arid zone

Comparative studies of sympatric species that integrate both phylogeographical and population genetic approaches provide insight into how demographic events and life history traits shape adaptive potential and drive species persistence. Such studies are rare for species-rich and strongly structured environments, especially those of the southern hemisphere. For two sympatric, perennial shrubs of the south-west Western Australian semi-arid zone, Grevillea globosa and Mirbelia sp. Bursarioides, we assessed historical and contemporary genetic diversity and structure, demographic processes and ratios of pollen to seed dispersal. Phylogeographical structure was not detected and haplotype networks were star-like. Number of haplotypes, nucleotide diversity, haplotype diversity, and allelic diversity were statistically significantly lower for G. globosa than for M. sp. Bursarioides. Levels of haplotype divergence and more contemporary genetic divergence and expected heterozygosity were lower for...