Validation of a rapid wetland ecosystem services assessment technique using the Delphi method

Abstract

Wetlands differ in their ability to provide ecosystem services, and thus there is a need to assess ecosystem service delivery in order to prioritize protection and restoration efforts. We used a Delphi-based expert-panel method to validate an ecosystem services assessment technique in a context where there is a paucity of field-level process-based research into the delivery of ecosystem services. The validation process entailed comparing scores from a panel of wetland experts to that derived by WET-EcoServices. Three wetlands were selected where detailed information relating to the supply of regulating services was available. At each site a selection of regulating services was assessed and then scored using the technique and independently by the panel of experts. The expert panel reached high levels of consensus (83%) on the scores for the three case studies used in the validation process. The consensus formed a useful basis for the validation of the technique. Statistical testing revealed no significant differences between expert and technique scores however, when considered practically, there were small differences in 53% of the scores, moderate differences in 23% and large in 20%. In most cases the technique over scored relative to the expert assessment. The results were useful for identifying specific refinements to the technique. The study demonstrates how a three-way “engagement” of a rapid-assessment technique, expert opinion and detailed research can be used to improve ecosystem services assessments in resource-limited situations. We reflected on the use of the Delphi method in a resource-constrained environment and advocate its careful application in similar contexts.