Evaluation of Perceptions Using Facial Expression Scores on Ecological Service Value of Blue and Green Spaces in 61 Parks in Guizhou

This study selected 61 parks in Guizhou province as research points and collected 3282 facial expression photos of park visitors in 2021 on the Sina Weibo platform. FireFACE v1.0 software was used to analyze the facial expressions of the visitors and evaluate their emotional perception of the landscape structure and ecosystem service value (ESV) of different landscape types of blue–green spaces. Research shows that the average ESV of green spaces in parks is USD 6.452 million per year, while the average ESV of blue spaces is USD 3.4816 million per year. The ESV of the blue–green space in the park shows no geographical gradient changes, while the happiness score in facial expressions is negatively correlated with latitude. Compared to blue spaces, green spaces can better awaken positive emotions among visitors. The ESV performance of different types of green spaces is as follows: TheroponcedrymV > GrasslandV > Shrubland V. The landscape structure and ESV of the blue–green space in the park can be perceived by visitors, and GreenV and vegetation height are considered the main driving factors for awakening positive emotions among visitors. In Guizhou, when the park area decreases, people are more likely to experience sadness. Regressions indicated that by increasing the green space area of the park and strengthening the hydrological regulation function of the blue–green space, people can achieve a more peaceful mood. Overall, people perceive more positive sentiments with high ESV in blue–green spaces of Karst parks but low ESV in shrubland.