Global costs of plant invasions must not be underestimated

The impacts of biological invasions have become a key focus of researchers in recent decades, leading to a rapid accumulation of evidence on economic losses associated with invasions. In a synthesis paper, Diagne et al. (2021) use a new database, InvaCost (Diagne et al. 2020), to quantify the global economic costs of biological invasions. They demonstrate that the global costs associated with invasive alien species are massive, at least US$ 1.3 trillion between 1970 and 2017, and increasing rapidly. Such high costs emphasize the critical importance of preventing and controlling biological invasions. Their paper thus delivers an important and much needed contribution to invasion science, which can strengthen invasive alien species management and policy globally. However, the costs of plant invasions presented by Diagne et al. (2021) are substantially underestimated compared to those of vertebrate and invertebrate invasions, and with respect to the available literature. While Diagne et al. (2021) state that the reported costs have pronounced geographic and taxonomic gaps, we believe that their significant underestimation of plant costs in comparison with other taxonomic groups needs to be clarified, to correctly demonstrate the severity of plant invasions and guide appropriate prioritization, budgeting, and allocation of limited management resources