Conservation and Management of Acacia in Australia

Acacia species (‘acacias’ or ‘wattles’) are primarily found in Australia, where they occur across the continent and occupy a wide range of habitats. While acacias are dominant in arid environments, centres of species richness occur in south-western Australia, the McPherson–Macleay Overlap and the Central Coast in eastern Australia. Nearly half of the many centres of endemism occur in the south-western Australian centre of species richness. Acacia makes up 5% of the listed threatened plant species in Australia and most threatened taxa occur in centres of species richness, with nearly half occurring in south-western Australia. Acacias dominate many ecosystems, and several acacia-dominated ecological communities are listed as threatened. Many threats affect multiple species and ecological communities, including changed fire regimes, land clearing, habitat fragmentation and degradation, and grazing by herbivores. Active management of these threats is required with in situ and ex situ recovery actions involving direct threat management and promoting natural regeneration, as well as translocation of threatened species and ecological restoration of species and habitats, supported by ex situ seed banking. Acacia species generally have impermeable seeds that require heat treatment or scarification to germinate, and typically regenerate following fire. They also show a range of levels of genetic diversity and differentiation among populations and are self-incompatible or have mixed mating systems. Many species can also reproduce asexually through suckering or resprouting, which may be advantageous in arid environments, and apomixis (the development of an embryo without fertilization) is also known to occur in some Acacia species. Knowledge of seed biology and genetics provides important information for implementation of effective management and conservation of acacias.