Modelling alternative management strategies of invasive tree species at the expansion front: Ligustrum lucidum as a case study.
Abstract
Managing invasive non-native species is a global challenge, especially for long-lived trees like Ligustrum lucidum, known for its detrimental effects on invaded ecosystems. Using individual-based models (IBMs), we simulated different control methods on the population dynamics and range expansion propensity of the established population. Across different sets of simulations, we varied the number of life stages and sites targeted. We additionally investigated how changing the management strategy over time affected outcomes. Controlling all life stages was essential to contain the expansion of L. lucidum. Removing both reproductive and non-reproductive stages was more than twice as effective as removing either saplings or reproductive stages only, especially if a high number of sites were targeted every year. The method of selecting sites for removal within the population was important if only saplings were removed; in which case targeting the most recently colonized sites was the most effective strategy. Finally, a strategy that switches after 5 years from controlling all stages to focusing exclusively on early life stages could be effective at reducing both the total population size and the area occupied. Practical implication: This approach could be valuable when the availability of long-term resources for control is limited. The ability of IBMs to simulate various scenarios and assess outcomes at population and landscape levels enhances their utility for predicting invasive non-native species management success. It can be a solution to reducing the time and cost of fieldwork, helping to identify potential limitations of control actions.