Extending a Bayesian Belief Network for ecosystem evaluation

This paper explores the use of a Bayesian Belief Network (BBN) to model ecosystem services valuation. It links the stages of the process from the functioning of the natural ecosystems through the delivery of service to the human stakeholders to the valuation stakeholders put on the service delivery. The BBN is a graphical decision tool with nodes representing the states of the system and links encapsulating the evidence for dependence between parent and child nodes. A BBN differs from other decision tools because it uses probabilistic reasoning throughout, and so these networks can propagate uncertainty and can adjust for differing spatial and temporal scale dependences. The framework has been developed through application to case studies and through consideration of the requirements of one of Scotland’s National Parks. Further developments to improve the use of the tool for ecosystem services and environmental impact assessment are discussed.