Advocates of ecotourism often invoke a 'win-win-win' message of eco­tourism's potential for people, profits and the planet. Since the late 1980s, global environmental organizations and multilateral development agencies have invested heavily in ecotourism with the hope that it can meet people's needs while also protecting the environment. Sometimes the goals have been mutually reinforcing and, in places, ecotourism has succeeded at building social and economic foundations for conservation (Alexander, 2000). In other places, ecotourism has failed to deliver benefits either for people and or the environment (Belsky, 1999). In yet other cases, ecotourism has benefited people, but caused direct damage to species and ecosystems (Isaacs, 2000). Success and failure in ecotourism have varied over time as well. Short-term economic gains in some places have led to degradation of resources over time (Barrett et al., 2001). An overriding challenge for conservationists is to find the conditions under which ecotourism works for people and environment, both now and into the future. At the core of many ecotourism projects is a social and economic paradigm that functions, at least in the aspirations of project managers, as something like an equation (Malek-Zadeh, 1996). The equation posits that ecotourism (£), when multiplied by economic benefits (B) and divided equitably among local residents (R). equals conservation ( C): E (B/R)=C. Calculating this 'equation' in real life often entails calculating ·E as numbers of tourists, rooms occupied, vacation days or expenditures, and measuring ·B' as total revenues, number of jobs created or volume of local commerce generated. The · C for conservation seldom gets measured in the same way by researchers across sites, although often it is summarized as a ·conservation ethic', expressed in reported attitudes or values, or as a set of behaviours. such as the limiting of harvest rates or the establishment of a reserve or protected area (Agrawal and Redford. 2006).