Scanning the horizon for invasive plant threats to Florida, USA

Early detection and eradication of invasive plants are more cost-effective than managing well-established invasive plant populations and their impacts. However, there is high uncertainty around which taxa are likely to become invasive in a given area. Horizon scanning, which pairs rapid risk assessment with consensus building among experts, can help identify invasion threats. We performed a horizon scan of potential invasive plant threats to Florida, USA—a state with a high influx of introduced species, conditions that are favorable for plant establishment, and a history of negative impacts from invasive plants. We began with a list of 2128 non-native plant species and subspecies that are crop pests or invasive somewhere in the world and used publicly available data to prioritize 100 taxa for rapid risk assessment. We derived overall invasion risk scores by evaluating the likelihood and certainty of each of the 100 taxa arriving, establishing, and having an impact in Florida. Through the rapid risk assessments and a consensus-building discussion, we identified six plant taxa with high overall risk scores ranging from 75 to 100 out of a possible 125. The six taxa are globally distributed, easily transported to new areas, found in regions with climates similar to Florida’s, and can impact native plant communities, human health, or agriculture. We recommend more thorough risk assessments for each of these six species and, if appropriate, policy and management actions to limit invasive plant introduction and establishment in Florida.