Quantifying the trends expected in developing ecosystems

In this paper we describe an assessment of ecosystem health that is both comprehensive in that it is based on a series of common trends associated with the process of ecological succession, and operational in that the indices capable of quantifying these trends can be easily calculated given appropriate simulation model output or estimates of material exchange. We developed a simulation model which generated output characteristic of an ecosystem advancing through the various stages of succession to test the ability of a suite of systems-level information indices to quantify these trends. Our regression analyses suggest that these indices may be able to capture the trends associated with ecological succession, hence the reversal of many of these trends characteristic of ecosystem response to anthropogenic stress. We further argue that indice performance could be enhanced with the use of more dynamic modelling techniques. In addition, we introduce a methodology for the valuation of non-marketed ecosystem components which could be easily included with our assessment of ecosystem health. We conclude that this measure of ecosystem health in combination with the valuation technique may provide an informative compliment to many past and future regional modelling projects aimed at better understanding and managing the impacts of anthropogenic stress on our regional ecosystems. (C) 1998 Elsevier Science B.V. All rights reserved.