Strategic management of the highly invasive Buddleja davidii within New Zealand in a changing climate.

Buddleja davidii Franchet is a very high impact exotic weed that competes strongly with forest plantations in New Zealand. While it is currently restricted mainly to the North Island, a large proportion of the area identified for future forest expansion is in eastern and southern regions of the South Island where the weed is presently relatively scarce. Using a process-oriented climatic niche model (CLIMEX), we project increases in climatic suitability for the weed under climate change to be greatest in these eastern and southern regions of the South Island. As B. davidii predominantly colonises disturbed areas, the likely future increases in plantation area in this region can be expected to promote the spread of B. davidii. Various climate-change adaptation strategies that could be implemented to reduce the spread of B. davidii are discussed.