Mapping and assessment of karst landscape aesthetic value from a world heritage perspective: a case study of the Huangguoshu Scenic area

Aesthetic value is an essential component of outstanding universal value (OUV) for natural world heritage (NWH) site. However, comparisons of aesthetic value lack a set of effective evaluation systems. In the identification of aesthetic value, there is subjectivity and difficulty in quantifying the methodology suggested by the IUCN in the operation manual, and it is difficult to compare in different NWH sites. This study focused on establishing a universal system to map and assess the aesthetic value of karst NWH sites. The research focused on three dimensions: naturalness, diversity, and uniqueness. The final combination of the three is achieved by geographic information system (GIS)-based spatial map overlay analysis with multisource data. To verify the rationality of the model, the aesthetic value of a case study in the Huangguoshu Scenic Area in China at the WH nominated site was evaluated. The results revealed that the areas with low, relatively low, medium, relatively high, and high values accounted for 12.2%, 20.2%, 32.4%, 21.4% and 13.8%, respectively. The distribution of aesthetic value is basically consistent with the boundary division of the NWH site, and high scores are mostly distributed in areas with high protection levels. Moreover, the impacts of naturalness, uniqueness and diversity on aesthetic value in the research area are in decreasing order. Furthermore, the research analyses the aesthetic characteristics and causes at different levels. The research area combines the quintessential nature of karst, hills and water, caves, fenglin and historic villages; it unifies sturdiness, peculiarity, precipitousness, and peace. Among the 7 nominated NWH sites, the Huangguoshu Waterfall has the highest aesthetic value, while those of Tiantaishan Ancient Temple and Getuhe are relatively low. The rationality of the evaluation system for extracting areas with high aesthetic value was demonstrated. This study compensates for the limitation of the inability of existing studies to quantify the aesthetic value. This approach fills a previous gap in the research on the aesthetic value of WH and can provide a useful reference for better protection and management decisions.