Biodiversity is usually regarded as an asset or resource, the stock of which is partly natural and partly determined by humans. Humans both subtract from and add to this stock and consequently, the change in the stock is heterogeneous. This heterogeneity is not taken account of by some authors...

Several different concepts of sustainable development exist in the literature (Tisdell, 1993, Ch. 9). However, it seems that no matter which of these concepts is adopted conservation of biological diversity is necessary for its achievement, even though there is room for argument •about the...