A salience index for integrating multiple user perspectives in cultural ecosystem service assessments

Cultural ecosystem services (CES) include non-material values such as recreation, aesthetic enjoyment, and spiritual fulfilment. Such values are culturally specific, and frequently difficult to measure and monetarize. The standard methodology to assess CES is through social surveys, though these are often costly, lack standardization and are geographically restricted. An alternative to surveys is to use information from social media. Here, we propose a novel salience index to quantify and compare CES provision for multiple user groups (local residents, researchers and visitors) of Catimbau National Park in Brazil using data derived from distinct methodologies: i) a traditional social survey; ii) an online survey, and iii) analysis of photos published on Flickr and Instagram. Our index allowed direct comparison between groups despite the data being collected using different approaches. As predicted, residents identified more locations providing CES and a higher overall diversity of CES. Correspondingly, researchers and visitors identified CES from a more restricted set of locations and were biased towards educational services and aesthetic value, respectively. Since multi-stakeholder, multi-method approaches are essential for a comprehensive understanding of CES, integrating results using standardized metrics such as our salience index will allow broad scale analysis of this poorly quantified class of ecosystem services.