Thu, Aug 18, 2022: 5:00 PM-6:30 PM
ESA Exhibit Hall
Background/Question/Methods: Increases in regional connectivity are effectively intensifying establishment of self-sustaining populations of invasive plants around the globe. However, some ecosystems are disproportionately susceptible to incoming species. This range of potential susceptibility is described as invasibility, or the propensity for an ecosystem to be invaded by non-native organisms. It is imperative to determine contributing factors of regional invasibility and predict potential future invasions. Yet, we lack a global picture of invasion potential. Exotic fraction, or the proportion of an ecosystem that is already invaded, estimates the degree by which invasive species have established in an ecosystem by calculating the proportion of exotic plant species to native and exotic plant species in an ecosystem. In this study, we used a recently compiled global data set of invasive plant distributions to calculate exotic fraction for regions across the globe. We then modeled exotic fraction for each region using predetermined variables that facilitate invasion success. We calculated the differences between observed and predicted values of exotic fraction to identify potentially high-risk regions. While invasion potential has been estimated elsewhere, this study is the first to use exotic fraction to estimate regional invasibility on a global scale.
Results/Conclusions: Overall, we found considerable variation in global invasibility, with some trends in high and low values. Our analyses revealed highest invasibility for two island regions in Australasia. New Caledonia, a French territory, is signatory to the highest number of global and regional international treaties mentioning invasive species in the world and has extensive legislation and regulations dedicated to prevention and management of invasive species. As New Caledonia has high potential for future invasions, careful attention should be paid to the effectiveness of current policies on invasive species. The island of New Guinea was colonized by the Dutch and is currently two separate entities. Conversely, New Guinea does not have legislation or regulations dedicated to prevention or management of invasive species. As a region with high potential for future invasions, and with little to no preventative efforts, this could be an area of great concern and potential opportunity. An appropriate invasibility metric, as the one developed here, has been largely lacking from invasion literature despite its potential to guide effective, pre-emptive strategies for invasion prevention. We suggest that this tool is used as an efficient method to determine regions of greatest priority and opportunity for successful mitigation of threats from invasion.
Results/Conclusions: Overall, we found considerable variation in global invasibility, with some trends in high and low values. Our analyses revealed highest invasibility for two island regions in Australasia. New Caledonia, a French territory, is signatory to the highest number of global and regional international treaties mentioning invasive species in the world and has extensive legislation and regulations dedicated to prevention and management of invasive species. As New Caledonia has high potential for future invasions, careful attention should be paid to the effectiveness of current policies on invasive species. The island of New Guinea was colonized by the Dutch and is currently two separate entities. Conversely, New Guinea does not have legislation or regulations dedicated to prevention or management of invasive species. As a region with high potential for future invasions, and with little to no preventative efforts, this could be an area of great concern and potential opportunity. An appropriate invasibility metric, as the one developed here, has been largely lacking from invasion literature despite its potential to guide effective, pre-emptive strategies for invasion prevention. We suggest that this tool is used as an efficient method to determine regions of greatest priority and opportunity for successful mitigation of threats from invasion.