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.

代表自然生态系统所产生的娱乐活动的经济价值可以为其保护提供强大的动力。然而，要证明价值，就需要进行资源密集型调查或依靠从其他场所转移价值的技术。最新的技术发展为大量的地理参考公共数据做出了贡献，作为探索人与自然互动的一种选择，为昂贵且耗时的访问者调查提供了潜在的替代方法，并为娱乐，价值转移的评估提供了常用的替代方法。这里，我们（1）将来自社交媒体中带有地理标签的照片的众包数据整合到旅行成本法非市场估值技术中，并（2）使用通过对德国国家公园进行的代表性现场调查和价值转移技术所产生的价值估算来验证结果。正如标准经济和消费者对普通商品的需求理论所预期的那样，我们发现需求曲线呈下降趋势。进入公园的消费者剩余在16.54欧元和34.90欧元之间（2016年价格）。价值估计值与现场调查产生的估计值显着相关，平均绝对误差为4.93欧元，平均绝对百分比误差为22％，胜过基本单位价值转移。我们着重指出了为扩大户外娱乐价值而扩大范围并降低研究成本所带来的前所未有的机遇。