The current and future potential geographical distribution of Hyparrhenia hirta

P>Hyparrhenia hirta is a pasture grass that has become highly invasive in several parts of the world, including Australia where it has become a serious environmental weed in recent decades. Knowledge of the likely potential distribution and relative abundance of this invasive species, under current and future climate scenarios, will help biosecurity and weed control authorities to plan better strategies to manage the invasion. The CLIMEX modelling package was used to investigate the impacts of climate change on the potential global distribution of H. hirta, based on eco-physiological data. The worldwide potential distribution of H. hirta under current climatic conditions is vast and far greater than the current distribution, with suitable climate conditions extending over much of the tropics and subtropics. Under future climate scenarios, the range of H. hirta is likely to expand into areas currently too cold for its survival and contract from areas that are projected to become hotter and drier under climate change. The effects of likely climatic scenarios on the global potential distribution of H. hirta are sufficiently great that they should be considered routinely in strategic control plans for biotic invasions. Changes in the potential range of an invasive species such as H. hirta, under global warming scenarios, will mean that it could invade new jurisdictions. Knowledge of this emerging threat could help to formulate effective prevention, surveillance and response measures in these presently marginally unsuitable regions.