The Anthropocene is defined by human-induced environmental change, including climate change, land use change and alien species invasions. These changes have sparked a global biodiversity crisis. Human introduction of species beyond their historical biogeographic boundaries is one of the defining characteristics of the Anthropocene. Over 13,000 alien plant species are naturalised worldwide with numbers growing year on year. Here is the conundrum: alien species introductions could augment local and regional biodiversity, increasing ecosystem stability and productivity. If this were true, alien invasions could ameliorate some of the negative effects of native species loss. However, alien species that have become invasive are themselves among the top threats to biodiversity and have already contributed to at least 1,215 species extinctions worldwide. So, we must ask, under what conditions, through what processes and in what ways does alien plant invasion affect plant community diversity?
The fundamental aim of ALIENIMPACTS is to develop an approach for accurately predicting impacts of alien plants on floristic diversity, and to identify the circumstances under which negative impacts will occur, using temperate grasslands as a model system.
Using temperate grasslands as a model system, ALIENIMPACTS will:
1. Characterise the cause-effect relationships (dose-response curves) associated with the principal causes and mechanisms of invasion impact, and how they vary depending on context.
2. Quantify the proportion of alien plant species that have higher ecological fitness than co-occurring native species, the magnitude of that fitness advantage, and how long it lasts.
3. Develop new models, and a modelling approach, to predict the establishment and abundance of invading plant species in a site, and the resulting impact on plant community diversity.
By achieving its three project objectives, ALIENIMPACTS will realise its fundamental aim of developing the capacity to predict the impact of alien plant invasions on plant diversity at a community-scale. The modelling framework will be applied to temperate grasslands in three continents, but adaptable to other systems. This predictive capacity – and associated identification of indicators of high-risk high-impact invasions – will support biosecurity and natural resource management, guide conservation policies and practice, and inform trade, transport and production at local, regional and global scales. Extensions of ALIENIMPACTS would enable the efficacy of possible mitigation and management actions, and their trade-offs, to be evaluated.
