Format: ORAL

Peter Pemberton1, Rose Andrew1, Manu Saunders1, John Hunter1, Liz Wandrag2

1 University of New England, Armidale, Australia 2 University of Tasmania, Hobart, Australia

Old Climatically Buffered Landscapes (OCBILs) often exist as terrestrial islands that are isolated in a larger landscape matrix, and plants confined to OCBILs have a high incidence of endemicity and rarity. Shrubs are a significant component of OCBIL vegetation, yet many have restricted gene flow due to a lack of seed dispersal mechanisms, and a reliance on insect pollinators with limited ranges. We hypothesise that the persistence of these shrub species in small and isolated populations limits the adaptive potential that arises from gene flow between populations. We conducted a systematic review of molecular ecology papers on OCBIL species to identify where the research has occurred and what the molecular ecology revealed about OCBIL flora. We identified geographic gaps and a paucity of studies focusing on shrubs, whilst species pollinated by insects alone tended to have highly structured populations with low gene migration rates, underlining the need to understand how OCBIL shrubs diversify and persist. On the basis of this review, we will now research the genetic diversity and gene flow at multiple scales in the New England Tableland region of Australia, a region with relatively understudied OCBILs. Fine-scale analysis of relatedness and spatial autocorrelation at centimetre precision will investigate patterns of gene flow and dispersal within granite outcrop populations. In concert with observations of flower visitors, comparisons among age cohorts will illustrate the influence of geography and insect-mediated pollination on gene flow at the finest scale. Using coalescent estimates of migration rates and population divergence in OCBIL and non-OCBIL taxa, we can begin to understand the demographic history and adaptations of terrestrial island flora. This research sheds light on the mechanisms by which small, isolated populations persist, and their capacity to adapt to novel conditions under global climate change.