- Evolutionary ecology research
- Australian rain forest community assembly
- Australian rain forest through time
- Ecology of Cumberland Plain Woodland
- Bicentenary Plant Diversity Program
- Biodiversity Adaptation Transect
- Botany of Botany Bay
- Conservation genetics
- DNA studies of Elaeocarpaceae
- Ecology of Isopogon prostratus
- Floristic Lists of NSW
- Habitat fragmentation
- Lomatia (Proteaceae)
- Molecular phylogeny of the Australian Lauraceae
- Promiscuous Lomatia
- Promiscuous Proteaceae
- Native plants of Sydney Harbour NP
- Newnes Plateau Shrub Swamps
- Next Generation Sequencing
- Nickel hyperaccumulation in Stackhousia
- NSW Vegetation Classification & Assessment Project
- Plants of the Newnes Plateau
- Plants, vegetation, landscape, country
- Phylogenetic relationships of Ceratopetalum
- Podocarpus elatus
- Rainforest conifer - Podocarpus elatus
- Speciation in Proteaceae
- Testing speciation models
- Horticultural research
- Plant diversity research
- Plant pathology research
- Herbarium & resources
- Scientific publications
The response of a genus to biogeographic barriers in south-eastern Australia
Lomatia (Proteaceae) is a genus of 12 species, occurring in South America (three species), eastern mainland Australia (six species) and Tasmania (three species). In mainland Australia five of the species have distributions that overlap extensively, with a distribution from the Otways in Victoria to central Queensland. We predict that closely related species with a shared distribution would have a similar response to the same barriers.
We used chloroplast DNA to assess genetic differentiation across five sympatric (i.e. species evolving from a single ancestor in the same geographic area) species of Lomatia. The majority of resulting genetic groups, known as chlorotypes, were shared across species, indicative of both retention of ancestral lineages and more recent hybridisation. The chlorotypes displayed a geographical relationship, where the pattern of differentiation was more indicative of location than species relationship. The geographical pattern of chlorotype distribution was also responsive to known biogeographical barriers. The most significant of these was the Hunter River valley (HRV). Despite the widespread chlorotype sharing, chlorotypes were differentiated on either side of the HRV. Whilst the HRV has been assumed to be a significant barrier for eastern Australian flora, there is very little molecular evidence to support this, making this study one of few to show itís impact Hunter River valley on genetic differentiation and distribution.
Evolution in Lomatia was also influenced by other biogeographical barriers in eastern Australia. For example, a number of unique chlorotypes were restricted to the east Gippsland region, which is a marine incursion zone that in the past has been submerged, with only isolated pockets of vegetation surviving during this period. Several biogeographical barriers at the NSW-QLD border have also influenced distribution of species and genetic differentiation. The McPherson/Main Ranges along the border are likely to have been refugia for species during times of increasing aridity, and further south the Clarence River Corridor is a dry corridor recognized as a barrier for mesic species.
Another region of genetic differentiation was found in the southern NSW/ACT region, believed to be a transitional barrier as species suitability changed throughout the varying climatic cycles and resulting glaciation and aridification.
This study has identified a number of important biogeographical barriers that have influenced the distribution and differentiation of Lomatia in eastern Australia. Further investigation on genetic differentiation across the genus is currently focusing on markers using DNA from the nucleus of the cell.