Risks of species introduced for biological control

Numerous biological control introductions have adversely affected non-target native species. Although many of these problems occurred in the early days of biological control, some are recent. Because of how little monitoring is done on species, communities, and ecosystems that might be affected by biological control agents, it is quite possible that known problems are the tip of an iceberg. Regulations for officially sanctioned releases for biological control are insufficient, and there are also freelance unregulated releases undertaken by private citizens. Cost-benefit analyses for conservation issues, including those associated with biological control, are exceedingly difficult because it is hard to assign values to the loss of species or ecosystem functions. Risk assessment for biological control is difficult because of how hard it is to predict community- and ecosystem-wide impacts of introduced species and because introduced species disperse and evolve. Nevertheless, cost-benefit analyses and risk assessments for biological control introductions would have the salubrious effect of forcing consideration of myriad factors that now often receive cursory attention and of broadening public understanding of the issues. Copyright (C) 1996 Published by Elsevier Science Limited