The methods that can be used for valuing biodiversity are still evolving at the global level, but studies have been done on how biodiversity values can be incorporated into the process of decision making for investment projects. In carrying out valuation studies, it i s necessary to emphasize the importance of adopting appropriate criteria and methods and focusing on values that are of relevance to the respective countries. In this regard, however, we need to be able to see the distinction between valuing only individua l biological resources and valuing biological diversity (i.e. the existence of a range of variation in biological resources, whether measured quantitatively or qualitatively).
A balanced approach to understanding the values of biodiversity in the context of ecosystem services should be based on the understanding that people in all countries and regions depend daily on ecosystem services from terrestrial as well as aquatic habitats for managing their lives. This underscores the need to value and conserve th e natural ecosystems of all countries and regions rather than only on biodiversity hot-spots or charismatic species. Identification and recognition of ecosystem services is therefore required at various scales from local to regional, national and global.
Overall, while it is evident that neither ethical nor aesthetic arguments alone provide sufficient grounds for attempting to maintain all the earth's existing biological diversity. A more general and practical approach recognizes that different but equally valid values (resource values, optional values, ethical and aesthetic values, etc.) can assume importance in different cases, and together can provide an overwhelmingly powerful case for the conservation of the earth's biodiversity. In current practice, many of the arguments used to justify the conservation of biodiversity stress the benefits, both economic and otherwise, from the sustainable use of biological resources. However, arguments for biodiversity conservation on economic grounds alone is insuffi cient to ensure its long term preservation. It is a fact that aesthetic, moral or other values are just as valid and necessary as financial values to justify the conservation of biodiversity.