The habitat of Acacia auriculiformis and probable factors associated with its distribution.

Abstract

This paper describes the current distribution of Acacia auriculiformis in Australia (Northern Territory and Queensland), Papua New Guinea and Indonesia, including details of the forest (population) types in which it is found in each; these include coastal, sub-coastal, riparian, isolated monsoon vine, floodplain and swamp forests. Climatic data for six climatically defined groups within the species distribution are indicated. Details are given of past geological and climatic events that are likely to have been important in moulding the current distribution. The species is fairly primitive and may have evolved on rain forest fringes sympatrically with Acacia aulacocarpa and Acacia crassicarpa. In recent times it is likely to have expanded from monsoon vine forests and gallery rain forests when conditions were favourable. The species is opportunistic and very mobile. Rising sea levels and periods of aridity are probably the major factors determining its current disjunct distribution. Implications for seed collection programmes and for the interpretation of results from biosystematic studies are discussed.