Functional eradication as a framework for invasive species control

Abstract

Invasive species continue to drive major losses in biodiversity and ecosystem function across the globe. Dealing with the effects of invasion is particularly problematic in marine and freshwater habitats, because the pace at which invaders establish often greatly outstrips the resources available for their eradication. While most managers in North America now focus on ongoing containment and suppression interventions, they often lack quantitative guidance from which to set targets and evaluate success. We propose practical guidelines for identifying management targets for invasions for which eradication is unfeasible, based on achieving “functional” eradication – defined as suppressing invader populations below levels that cause unacceptable ecological effects – within high‐priority locations. We summarize key ecological information needed to inform this strategy, including density–impact functions and recolonization rates. We illustrate the framework's application for setting local suppression targets using three globally invasive species as examples: red lionfish (Pterois spp), European green crab (Carcinus maenas), and rusty crayfish (Faxonius rusticus). Identifying targets for suppression allows managers to estimate the degree of removal required to mitigate ecological impacts and the management resources needed to achieve sufficient control of an invader.