Integrating Diverging Goal Functions: Time Scale Effects with Respect to Sustainability

Abstract

The conflict between the economic and the ecological point of view can be interpreted as a conflict between economic and ecological goal functions. Using the example of land-use in the southern Kalahari we apply the framework of goal functions to the problem of developing strategies of sustainable management. We use a grid-based simulation model to identify an appropriate ecological goal function. As a result, the widely used generic goal function of deterministic, continuous succession up to a climax state turns out to be inappropriate. Instead, the systems changes abruptly between distinct states which are separated by thresholds. Based on this experience and on a discussion of ‘classical’ goal functions such as equilibrium and stability, we argue that for developing strategies of sustainable management generic ecological goal functions should only be used with great caution. Management should instead be based on the identification and understanding of the goal function which is characteristic of the particular system in question. The application of these tailored goal functions is necessarily linked to an explicit acknowledgment of time horizons and inherent uncertainties, which are due to random fluctuations.