Speciation and the maintenance of species boundaries are the main evolutionary processes shaping biodiversity, yet neither is well understood. However, the field is entering a new phase of discovery thanks to our rapidly growing ability to acquire and work with large amounts of environmental and molecular data. Key knowledge gaps are: (i) how environmental variation acts on both genotypes and phenotypes to drive divergence between populations up until the emergence of reproductive barriers; and (ii) how climate change will affect this process to either enhance or weaken species barriers and ultimately change patterns of biodiversity. My PhD aims to help bridge these gaps by using a cutting-edge combination of environmental, genomic and experimental data. I will do so in a rapidly-warming marine hotspot on Australia’s southeast coast. Here, the habitat-forming native marine tubeworm, Galeolaria, has undergone speciation, forming two partially-isolated cryptic species. So far, I have developed a general framework on how to use environmental variation to predict evolutionary outcomes across space and I have analysed sea surface temperature (SST) data in combination with molecular data (single nucleotide polymorphisms) to assess temperature as a potential agent of divergent selection in Galeolaria (i.e., genotype-environment correlations), delivering preliminary results. In the upcoming year, I will assess local adaptation among populations using within-population crosses at native and non-native SST. Then, I will assess the strength and nature of reproductive barriers, together with their maintenance under future climate conditions, using between-population crosses at a basal temperature level plus 1°C and 3°C of warming. By completing my PhD, I expect to contribute new knowledge in the field of evolutionary biology and speciation, and to deliver predictions about the maintenance of species boundaries under climate change, thereby aiding in the conservation and management of Australian biodiversity.
|Effective start/end date||30/06/20 → 31/05/21|