Invasive species eradication: How do we declare success?

Abstract

Deciding whether or not eradication of an invasive species has been successful is one of the main dilemmas facing managers of eradication programs. When the species is no longer being detected, a decision must be made about when to stop the eradication program and declare success. In practice, this decision is usually based on ad hoc rules, which may be inefficient.Since surveillance undertaken to confirm species absence is imperfect, any declaration of eradication success must consider the risk and the consequences of being wrong. If surveillance is insufficient, then eradication may be falsely declared (a Type I error), whereas continuation of surveillance when eradication has already occurred wastes resources (a Type II error). We review the various methods that have been developed for quantifying these errors and incorporating them into the decision-making process. We conclude with an overview of future developments likely to improve the practice of determining invasive species eradication success. Impact StatementWe review the latest quantitative methods that can be used to analyse surveillance data to estimate the probability of species absence, when no individuals are detected. These methods allow defendable and transparent decisions to be made about the probability of successful eradication. Decisions associated with eradication operations need to be evidence-based to ensure cost-efficient strategies are adopted and to satisfy concerns of funders, policymakers, managers and the public.

Managing invasive hybrids with pond hydroperiod manipulation in an endangered salamander system

“…The global proliferation of invasive species requires the exploration of novel methods to complement traditional management strategies like targeted removal. Even without the complications imposed by hybridization, declaring the success of invasive eradication is difficult at best (Ramsey et al., 2023). We explored the restoration of human‐modified ponds to their historically ephemeral condition to reduce the success of non‐native genotypes.…”