DISTRIBUTION

Global | In Australia | The Acacia Community | South-eastern Australia | Diversity

Species richness in south-eastern Australia

Over 80 species of Acacia (as well as a high diversity of Eucalyptus species) occur in central-eastern New South Wales, particularly in the Hunter Valley area, where there is a large diversity of habitats, climate and soil types. A similar abundance of Acacia species (exceeding 100) is found in the south-west of Western Australia and this has been attributed to the extreme fluctuations of climate during the Quaternary, producing many and changing habitats and consequently fragmenting and isolating species resulting in a high rate of speciation¹². These same factors were probably at work in central-eastern New South Wales where the fluctuating climates of the Quaternary had their greatest impact on the vegetation. Somewhat similar to the south-west botanical province in Western Australia¹², Acacia species richness in the south-east of Australia is predominately in Sections Plurinerves and Uninerves (particularly the Racemosae and Botrycephalae) , with Section

Fig. 7. Acacia species richness in SE Australia, showing also the rainfall

Juliferae being more northern. This richness of species is shown correlated with annual average rainfall for south-east Australia in Fig. 7.

Global | In Australia | The Acacia Community | South-eastern Australia | Diversity