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 lit tle monitoring is done on species, communities, and ecosystems that mi ght be affected by biological control agents, it is quite possible tha t known problems are the tip of an iceberg. Regulations for officially sanctioned releases for biological control are insufficient, and ther e are also freelance unregulated releases undertaken by private citize ns. Cost-benefit analyses for conservation issues, including those ass ociated 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 h ard it is to predict community- and ecosystem-wide impacts of introduc ed species and because introduced species disperse and evolve. Neverth eless, cost-benefit analyses and risk assessments for biological contr ol introductions would have the salubrious effect of forcing considera tion of myriad factors that now often receive cursory attention and of broadening public understanding of the issues. Copyright (C) 1996 Pub lished by Elsevier Science Limited