ABSTRACT
Natural ecosystems provide an array of critical but largely undervalued goods and services. Because these are seldom included in benefit-cost calculations of land use change, the value of wild land development nearly always appears greater than protecting wild nature. The following paper introduces a theoretical framework within which environmental economists evaluate ecosystem services. This is followed an assessment of three types of ecosystem services with particular relevance to the developing world pharmaceutical drug development from native plants, the economics of non-timber product extraction, and the benefits and costs of ecotourism as a development strategy. We conclude with an overview of recent attempts to provide a global estimate of the value of nature's services