Using qualitative food webs to predict species at risk of indirect effects from a proposed biological control agent

Abstract

Indirect effects of biological control agents (BCAs) are difficult to assess because they are mediated through the complex connections between species within the ecological community. Being able to visualise such complex connections by constructing qualitative food webs could greatly enhance our ability to predict indirect effects that could then be evaluated through empirical studies or modelling. Qualitative food webs were constructed for two case studies of entomophagous BCAs using the existing literature on invertebrate consumer relationships and status (e.g., as pest or rare species). We suggest that these webs can reduce uncertainty around the species that may be at risk, can predict species that perhaps should be monitored post-release, or identify knowledge gaps on species and their feeding relationships prior to the release of a BCA. Thus, these webs may be useful for those who need to consider the potential indirect risks of BCAs when making decisions about the release of a BCA into new regions.