Preventing and controlling non-native species invasions to bend the curve of global freshwater biodiversity loss.

Abstract

The Emergency Recovery Plan for freshwater biodiversity recognises that addressing non-native species is one of six principal actions needed to bend the curve in freshwater biodiversity loss. This is because introduction rates of non-native species continue to accelerate globally and, where these species develop invasive populations, they can have severe impacts on freshwater biodiversity. The most effective management measure to protect freshwater biodiversity is to prevent introductions of non-native species. Should a non-native species be introduced, however, then its early detection and the implementation of rapid reaction measures can avoid it establishing and dispersing. If these measures are unsuccessful and the species becomes invasive then control and containment measures can minimise its further spread and impact. Minimizing further spread and impact includes control methods to reduce invader abundance and containment methods such as screening of invaded sites and strict biosecurity to avoid the invader dispersing to neighbouring basins. These management actions have benefitted from developments in invasion risk assessment that can prioritise species according to their invasion risk and, for species already invasive, ensure that management actions are commensurate with assessed risk. The successful management of freshwater non-native species still requires the overcoming of some implementation challenges, including non-native species often being a symptom of degraded habitats rather than the main driver of ecological change, and eradication methods often being non-species specific. Given the multiple anthropogenic stressors in freshwaters, non-native species management must work with other restoration strategies if it is to deliver the Emergency Recovery Plan for freshwater biodiversity.