5. Discussion
‘‘The total value of biodiversity is infinite so having a debate about what is the total value of nature is actually pointless because we can’t exist without it.’’ (Robert Scholes, ecologist).The legitimacy of evaluating biodiversity remains at stake. Behind these criticisms, there may be some misunderstanding of what economic evaluation really means. The issue is not to put an economic value on nature,which would indeed be pointless, but to translate the value
of losses from the destruction of some ecosystems in terms that allow a comparison with other societal issues. Scholes’assertion is actually based on confusion between the economic value of the whole biosphere, which is obviously meaningless, and the sum of all economic reasons of
conserving or preserving a particular ecosystem. Even the latter, more limited purpose is hardly achievable in absolute terms, in the absence of a precise context of what threatens this ecosystem and how [87]. To go further in this direction, we will briefly review what should not be done and what should be tried, before discussing the contexts needed for meaningful evaluations of ecosystems.