AN ECOLOGICAL ECONOMIC SIMULATION-MODEL OF MOUNTAIN FYNBOS ECOSYSTEMS- DYNAMICS, VALUATION AND MANAGEMENT

Mountain fynbos ecosystems in South Africa are threatened by alien pla nt invasions and by a lack of funding for effective management of thes e invasions. This paper develops an ecological-economic argument for t he effective management of plant invasions in mountain fynbos ecosyste ms. We do this by building a dynamic ecological economic model which v alues the ecosystem services that fynbos ecosystems provide under diff erent management regimes. We propose that the services that mountain f ynbos ecosystems provide fall into six components: water production, w ildflower harvest, hiker visitation, ecotourist visitation, endemic sp ecies and genetic storage. A scenario analysis based on a hypothetical 4 km(2) mountain fynbos ecosystem in the western part of the fynbos b iome estimated that the ecosystem's value varies from R19 million (und er low valuation and poor management scenario) to R300 million (under high valuation and good management scenario) [R4.50=US$1]. Water produ ction and genetic storage were the most valuable ecosystem services. T he model showed that the cost of clearing alien plants (under the proa ctive management scenario) was a tiny (0.6-5%) proportion of the value of mountain fynbos ecosystems. This result motivates an injection of funds for clearing alien plants from mountain fynbos ecosystems. (C) 1 997 Elsevier Science B.V.