Valuing nature-conservation interests on agricultural floodplains.
The ecosystem approach and evaluation of ecosystem services is gaining increasing attention from scientists, practitioners and policy makers. An important part of this process is to establish the 'value' of the nature-conservation assets within an area. This value can then be compared with data for other ecosystem services to identify management priorities under different future scenarios. However, there is little consensus on how to perform such an evaluation. In this study, we assess seven methods of valuing nature-conservation interest and compare their utility. Five agricultural land drainage schemes across lowland England were selected for study. The current land-use was determined and four different scenarios of future management were developed. The land-use and habitats predicted under each scenario were assessed using seven methods of determining value, namely: Ecological Impact Assessment method, reserve-selection criteria, target-based criteria, stakeholder-choice analysis, reserve-selection criteria guided by stakeholders, agri-environment scheme payments and contingent valuation. The first three methods derive values based on pre-defined priorities, the next two use stated preferences of stakeholders, and the last two methods derive monetary values based on revealed and expressed preference, respectively. The results obtained from the different methods were compared. The methods gave broadly similar results and were highly correlated, but each method emphasized a different aspect of conservation value, leading to different possible outcomes in some cases. The advantages and disadvantages of each method were evaluated. Synthesis and applications. As the ecosystem services approach becomes embedded in decision-making, ecologists are increasingly called upon to value the biodiversity of a site or to compare the value of different sites. This study has shown that seven different valuation methods, although all giving significantly correlated findings, resulted in seven different rankings of nature-conservation value for the 25 situations studied. This difference occurred in spite of the sites being of the same landscape type and occurring within the same country. The discussion concludes that each method has its strengths; monetary valuations are appropriate in some contexts, stakeholder preferences are paramount in others, but where objectivity is key, then assessment against independently defined criteria or targets should be the preferred method.