Valuing nature-based recreation using a crowdsourced travel cost method: A comparison to onsite survey data and value transfer

Representing the economic value of recreation generated by natural ecosystems can provide a powerful incentive for their conservation. Demonstrating value, however, requires resource-intensive surveys or reliance on techniques which transfer value from other sites. Recent technological developments have contributed to an abundance of georeferenced public data as an alternative for exploring human-nature interactions, offering a potential substitute to costly and time-consuming visitor surveys and their commonly adopted alternative for the valuation of recreation, value transfer. Here, we (1) integrate data crowdsourced from geotagged photographs from social media into the travel cost method non-market valuation technique and (2) validate the results with value estimates generated using representative on-site surveys for German national parks and value transfer techniques. As expected from standard economic and consumer demand theory for ordinary goods, we find downsloping demand curves. Consumer surplus for access to the parks ranges between €16.54 and €34.90 (2016 rates). Value estimates are significantly correlated with those generated by on-site surveys, with a mean absolute error of €4.93 and a mean absolute percentage error of 22%, outperforming basic unit value transfer. We highlight the entailed, unprecedented opportunities to extend the scope and reduce costs of research seeking to value outdoor recreation.