Abstract
Significant climate changes are evident across Australia with declining rainfall and rising temperature, in conjunction with more frequent fire. Significant species loss and range contractions have been predicted, however the validity of these predictions is uncertain with critical gaps remaining in our understanding of the intrinsic capacity of species to respond to climate change. We quantified genome wide adaptive genetic variation in populations of Banksia attenuata, a prominent woody plant of multiple vegetation types in southwest Australia, evaluated the impact of declining rainfall, rising temperature and shortened fire intervals on population adaptive genetic variation. We characterised candidate genes associated with rainfall gradients, temperature, and fire interval through environmental association analysis. Population adaptive genetic variation was significantly impacted by shortened fire intervals, while declining rainfall and rising temperature have not had detectable influence so far. Candidate genes associated with rainfall and high temperature are diverse, with polymorphic alleles present in populations, while genes associated with specific fire intervals are fixed in one allele. Gene annotation further revealed four genes with function in stress tolerance, regulation of stomatal opening and closure, energy use, and morphogenesis with adaptation to climate and fire interval. B. attenuata, and perhaps other species with similar life history and distribution, may tolerate some further change in rainfall and temperature through evolutionary adaptation based on their adaptive genetic variation. However, the capacity to survive future climate change may be compromised by change in fire regime, and the capacity to survive more frequent fire and further environmental fluctuations is uncertain.