Fighting neobiota with neobiota: Consider it more often and do it more rigorously

Abstract

Invasive non-native plants (INNP) cause severe impacts on nature and human well-being, and these are predicted to increase. While management tools have been developed to control early-stage invasions or to clean particular sites from INNP, they are only rarely available to halt and reduce large-scale invasions. Importation biological weed control (IBWC; also termed classical biological weed control) offers a potentially effective tool, especially when combined with other land management interventions. Here, we aim to bridge the gap between IBWC advocates and critics by providing a state of the art of IBWC and exploring untapped opportunities and new ideas to further increase efficacy and safety of this tool. We first present a decision tree to identify the circumstances under which IBWC should be considered, either alone or as part of an integrated weed management approach. We then address concerns raised against IBWC by contrasting historical approaches with recently suggested improvements and outline a path forward. With two case studies, we emphasize that successful reduction of weed densities using IBWC will specifically also contribute to environmental health and human well-being by restoring ecosystem services without pesticide input and reaching areas with otherwise no INNP management options. We hope that our compilation helps to reconcile advocates and critics of IBWC and lead to a more constructive discourse and hopefully closer collaboration between the two groups. A joint effort is needed to further improve IBWC and to consider it more often, as the increasing threats imposed by INNP are urgently awaiting sustainable and affordable solutions.