Trends in the scientific literature exploring socio-cultural valuation approaches for cultural ES. Note: this illustration is not representing the total number of published papers on cultural services valuation, but the timeline of publications of the most relevant papers which focus on six cultural ES: non-extractive recreation and tourism (e.g. outdoor recreation, ecotourism), (2) extractive recreation and tourism (e.g. sport fishing, recreational hunting), (3) local ecological knowledge, (4) scientific knowledge and environmental education, (5) spiritual interactions with nature and (6) aesthetic experience.