3 decision support techniques that do not depend exclusively on market incentives and monetary valuation. The World Conservation Strategy published by the mCN (1980) recognised the full dimensions of these problems, and introduced the concept of sustainable development, placing the emphasis on the exploitation of natural systems and the use of biological natural resources within limits so that the availability of these resources for use by future generations would not be jeopardised by the current use of them. At this time, the imposition of quotas and the definition of critical loads and...

3 decision support techniques that do not depend exclusively on market incentives and monetary valuation. The World Conservation Strategy published by the mCN (1980) recognised the full dimensions of these problems, and introduced the concept of sustainable development, placing the emphasis on the exploitation of natural systems and the use of biological natural resources within limits so that the availability of these resources for use by future generations would not be jeopardised by the current use of them. At this time, the imposition of quotas and the definition of critical loads and...