asset would be needed to compensate for the loss of one unit of another type t capital asset. Ecologists express concerns that natural resources have only a limite set of substitutes. They fear that to the extent that economists are overly optimist about opportunities to substitute other capital assets for certain natural resource reductions in their stocks would then receive too little weight. A major goal ( ecological economics is to increase our understanding of the ways in which diffe ent kinds of natural capital contribute to human wellbeing and the extent to whic