Impacts of exotic biological control agents on non-target species and biodiversity: evidence, policy and implications

Over the last 20 years there has been increasing concern about environmental impacts of introduced biological control agents, and particularly the potential effect they might have on non-target organisms and biodiversity. This chapter will consider the range of policies that have been put in place in many countries to regulate the introduction of biological control agents. While each country has approached this in a slightly different way, in general policy has developed that requires a risk assessment for the proposed agent to be carried out, often coupled with other biosecurity focussed legislation that regulates quarantine provisions and associated organisms. Applicants need to identify and analyse risk, and predict likely post-release outcomes. In many cases they also need to calculate benefits, both financial and qualitative, and to consider the environmental and economic costs should their application to import a biological control agent be unsuccessful. Regulators then evaluate the evidence presented and additional information sourced from literature, often in addition to comments received from stakeholders, technical experts, and the public during a notification process. Regulating agencies conduct a full risk assessment and make a decision to approve a release or not. Providing robust data to support a case for environmental safety of a biological control agent, and minimising uncertainty from quarantine testing continues to prove challenging, arguably more so for biosafety testing of entomophagous agents compared with weed biological agents. Increasing consideration is being given to pathogens for biocontrol, which brings with it further unique challenges. Often it is claimed that there are insufficient resources to carry out post-release validation of predictions made from risk assessments, even to assess the beneficial impact of the biological control release on the target weed or pest, let alone to investigate adverse impacts on non-target species or biodiversity. We argue, however, with reference to case studies, that follow-up research can contribute enormously to our understanding of the implications of biological control releases, and more specifically to reducing uncertainty in future regulatory decision-making.