Combining asset- and species-led alien plant management priorities in the world’s most intact Mediterranean-climate landscape

Abstract

Minimising the spread and impact of alien plants is a crucial component of land management for biodiversity conservation. Alien plant management typically focuses on either controlling selected alien species (‘species-led’), or on minimizing invasions within selected biodiversity or cultural assets (‘asset-led’). Here, we compare and combine species- and asset-led approaches to prioritise alien plant management activities in the world’s largest Mediterranean-climate woodland, located in south-western Australia. Our species-led approach focused on identifying aliens likely to be increasingly problematic in future with a changing climate. Our asset-led approach used comprehensive flora survey data to identify key predictors of contemporary alien presence, with the purpose of minimising alien occurrence across the asset of a relatively little-disturbed landscape. Most aliens were associated with climates more mesic than are predicted to occur in the region in future. A limited range of alien taxa (12 %) are predicted to be both highly invasive in the future and feasibly eradicated or contained, and it is these that should be subject to species-led management. A consistent set of management-related predictors of contemporary alien presence were identified, including closer proximity to towns, buildings and water points, and occurrence on a geology and soil type associated with prospective mineral deposits. Addressing the highest management priorities of each approach would appear to be a complementary and parsimonious way forward for regional-scale alien management for biodiversity conservation, as this tackles the processes associated with contemporary alien spread (asset-led approach) while taking a precautionary approach to pre-empt future problematic invasions (species-led approach).