Climate change and the potential distribution of an invasive alien plant: Acacia nilotica in Australia
Acacia nilotica (Fabaceae) is a spinescent woody legume that has become highly invasive in several parts of the world, including Australia where it has been declared a weed of national significance. Understanding the likely potential distribution of this plant under current and future climate scenarios will enable policy makers and land managers to prepare appropriate strategies to manage the invasions.
CLIMEX software was used to identify areas at risk of further invasion in Australia so that appropriate measures could be undertaken in time. A potential distribution of A. nilotica in Australia under current climatic conditions was produced by the model. The latter was vast and far greater than the current distribution. Global climate change is likely to increase significantly the area at risk of invasion in Australia. The factors of most importance are the expected increases in water-use efficiency of A. nilotica due to increased atmospheric CO2 concentrations, allowing it to invade more xeric sites further inland, and increased temperatures, allowing it to complete its reproductive life cycle further towards the south. Simple quarantine procedures, such as installing paddocks, may provide a means of limiting the range of A. nilotica. The projected increased growth potential of A. nilotica throughout its current range suggests that if future management patterns result in seed pods lying unconsumed on the ground, additional vigilance may be required to identify and eradicate new invasion foci arising from flood dispersal. The increased growth potential may also result in a change of the economic balance, in favour of harvesting A. nilotica for agroforestery or bioenergy projects. Moreover, raising public awareness and identifying suitable control techniques are also crucial components in containing the invasion.
Sources
Kriticos DJ, Sutherst RW, Brown JR, Adkins SW, Maywald GF (2003) Climate change and the potential distribution of an invasive alien plant: Acacia nilotica in Australia. Journal of Applied Ecology 40, 111-124