Radiation of the Australian flora: What can comparisons of molecular phylogenies across multiple taxa tell us about the evolution of diversity in present-day communities?

The Australian fossil record shows that from ca. 25 Myr ago, the aseasonal-wet biome (rainforest and wet heath) gave way to the unique Australian sclerophyll biomes dominated by eucalypts, acacias and casuarinas. This transition coincided with tectonic isolation of Australia, leading to cooler, drier, more seasonal climates. From 3 Myr ago, aridification caused rapid opening of the central Australian and zone. Molecular phylogenies with dated nodes have provided new perspectives on how these events could have affected the evolution of the Australian flora. During the Mid-Cenozoic (25-10 Myr ago) period of climatic change, there were rapid radiations in sclerophyll taxa, such as Banksia, eucalypts, pea-flowered legumes and Allocasuarina. At the same time, taxa restricted to the aseasonal-wet biome (Nothofagus, Podocarpaceae and Araucariaceae) did not radiate or were depleted by extinction. During the Pliocene aridification, two Eremean biome taxa (Lepidium and Chenopodiaceae) radiated rapidly after dispersing into Australia from overseas. It is clear that the biomes have different histories. Lineages in the aseasonal-wet biome are species poor, with sister taxa that are species rich, either outside Australia or in the sclerophyll biomes. In conjunction with the fossil record, this indicates depletion of the Australian aseasonal-wet biome from the Mid-Cenozoic. In the sclerophyll biomes, there have been multiple exchanges between the southwest and southeast, rather than single large endemic radiations after a vicariance event. There is need for rigorous molecular phylogenetic studies so that additional questions can be addressed, such as how interactions between biomes may have driven the speciation process during radiations. New studies should include the hither-to neglected monsoonal tropics.

Placard on truck during Labour Day procession Brisbane 1966

Placard "Brisbane 1966 not Germany 1936" on truck during Labour Day procession Brisbane 1966. Image shows arrest of student during anti war demonstration in Brisbane, Australia, 1966. City Hall tower can be seen in background.

Conscription banner on truck during Labour Day procession 1966 Brisbane

Conscription headstone banner on truck during Labour Day procession 1966 Brisbane, Australia.

Education not war May Day 1968 Brisbane

Children on float during May Day march in Brisbane 1968. Banners say Education not war and Overseas for Peace Trade not war.

Moscow Circus performers during May Day march in Brisbane 1968

Performers from the Moscow Circus on float during May Day parade, Brisbane, Australia, 1968

Inala Darra Peace Committee during Hiroshima Day 1964, Brisbane

Members of the Inala Darra Peace Committee during Hiroshima Day 1964, Brisbane.

Graceville and District Peace Committee members with banner during Hiroshima Day 1964, Brisbane

Graceville and District Peace Committee members with banner during Hiroshima Day 1964, Brisbane, Australia.

Dockers utility in Labour Day procession 1965 Brisbane Australia

Holden utility carrying members of the Federated Ship Painters and Dockers Union during the Labour Day march in 1965, Brisbane, Australia. Anti conscription banners can be seen in the background, and the facade of the Pearl Assurance Building.

Young Labor demands better deal for Aborigines - Labour Day 1965 Brisbane Australia

Young Labor Association float during the Labour Day procession in Brisbane, Australia 1965. Placards call for voting rights for Aborigines, more education facilities and award wages.

Boys with placard during the Labour Day procession in Brisbane, 1965

Boys with placard during the Labour Day procession in Brisbane, 1965.

APSR Market Day

Notes for presentation

May Day procession 1967 showing Bill Sutton and other men

Marchers including Bill Sutton during Labour Day procession in 1967 outside Exhibition Motors, Brisbane, Australia.

Save our sons banner on float during May Day procession in Brisbane, Australia 1967

Save our sons banner on float during May Day procession in Brisbane, Australia 1967. Other signs on truck include No conscription and Death lottery 1967.

Woman with sash in sportscar during May Day procession 1967 Brisbane

Woman with sash in sportscar during May Day procession, 1967, Queen Street, Brisbane, Australia. Onlookers stand outside a Queenslander house.

Miss Equal Pay in sportscar during May Day procession 1967 Brisbane

Miss Equal Pay in sportscar during May Day procession, 1967, Queen Street, Brisbane, Australia.