Based on a meeting in April 1996 of international ecologists and economists who met to discuss the role of economics in designing procedures for biodiversity impact assessment. The group took the Convention on Biological Diversity as its mandate; in particular, the declaration `that it is vital to anticipate, prevent and attack the causes of significant reduction or loss of biological diversity at source.' A case-study approach was used, focusing on biodiversity loss in coral reefs, tropical forests, and savannahs and complemented by papers on different perspectives on the economics of biodiversity loss, ranging from the implications of macroeconomic policy to the economic benefits of ecosystem services.