Combining multiple indicators to determine conservation status based on expert preferences

Assessments of the conservation status of species depend on using multiple indicators, and most methods for combining indicators either assume that all indicators are equally important or they use some other pre-determined weighting. This article discusses the case of Canada's Wild Salmon Policy, which requires that the biological status of Conservation Units (CUs) of Pacific salmon (Oncorhychus spp.) be assessed by combining the status of several indicators or metrics. We developed a questionnaire for experts based on stated preference methods and found that the status of spawner abundance and trend in spawners metrics had the highest relative importance in assessment of CU status, especially for cases with high data quality and amount (DQA). Without information on metric status, DQA had little influence on CU status ratings. Our study presents a novel method for combining indicators to assess conservation status, and in future could be applied to other species and contexts.