Remember your roots: Biogeographic properties of plants' native habitats can inform invasive plant risk assessments

Abstract

AbstractAimReducing the effects of invasive plants is best accomplished by predicting which species will invade and preventing their introduction. To do this, risk assessments rely on a variety of plant traits and biogeographic properties to predict potential invasiveness. However, the relative importance of these traits and properties is unknown. Determining which biogeographic properties contribute the most to predicting invasiveness could improve the accuracy and reduce the time needed to complete future risk assessments. Here, we provide a comprehensive analysis and ranking of the biogeographic properties that best differentiate invasive and noninvasive plant species.LocationConterminous United States.MethodsWe compiled county‐level distributions of 10,721 vascular plant species native to the conterminous United States of which 884 were established elsewhere and 131 were invasive elsewhere. For each species, we used native distribution data to calculate biogeographic properties, including range size, human modification and abiotic niche breadth. We assessed the ability of biogeographic properties to predict whether each species was invasive outside of the United States using random forest classification models.ResultsVariables that represent the breadth of a species' native range, including the ranges of soil textures, ranges of soil fertility and total geographic area, are strong predictors of plant invasiveness. Models that included these variables correctly classified 86% of invasive species and 62% of noninvasive species. Variables representing resource availability and disturbance regime were not useful for distinguishing between established and invasive species.Main conclusionsFocusing on niche breadth properties could improve the accuracy of risk assessments and reduce the effort spent compiling information with lower predictive power. The importance of niche breadth in this analysis supports previous findings that broad physiological tolerance enables survival and reproduction in numerous environments, thereby increasing the likelihood of invasion.