Review Article A global review of risk-benefit-cost analysis for the introduction of classical biological control agents against weeds: a crisis in the making?

Risks of non-target effects resulting from releases of exotic organisms for the biological control of alien pests are a growing major concern because: (a) previous releases (<1%) are having significant negative impacts on rare native species, (b) alien organisms are a recognized global threat to sustainable agriculture and biodiversity, (c) risk analysis, as applied to environmental threats of species invasions and harmful effects of releases of genetically modified organisms, is a burgeoning field, and (d) biological control is increasingly being used in complex natural ecosystems where indirect impacts are harder to predict. As a result, governments are adopting a more risk-averse attitude to biological control as they assess such releases from an environmental and an economic standpoint. This is leading to more expensive and fewer successful release applications. In this paper we review the processes of risk analysis used by regulatory bodies around the world to pre-judge biological control releases against weeds. The aim is to publicize both strengths and weaknesses and to help encourage existing assessments to be fair to all without blunting the value of biological control as an effective tool against invasive alien weeds. The review, based around the five components of formal risk analysis (comparative analysis, risk assessment, risk management, risk evaluation, and risk communication), also focuses on how well the benefits and costs of biological control releases are evaluated in addition to the traditional analysis of the hazards. Currently only the New Zealand approach closely matches a full ecological risk-benefit-cost analysis of biological control releases with a precautionary approach, open consultation, a broad hazard/benefit definition in the release application and a judicial basis to the decision, but it comes at a high cost. Improving the analytical approaches used by countries runs a high risk of grinding biological control releases to a halt in a world where the precautionary approach has been adopted with respect to threats from exotic organisms on biodiversity (in line with the ‘precautionary approach’ set forth in principle 15 of the 1992 Rio Declaration on Environment and Development). The benefits of biological control remain poorly understood by the public, allowing the risks to attain disproportionate attention. We make recommendations to address this crisis in the making and discuss the outcomes of the review with respect to the inherent social risks of making analysis of biological control releases an overly protracted process.