The “2nd industry output value” was an extremely significant (ES) factor with the highest range in the response domain. The monotonic decreasing function of the “2ndindustry output value” and ESV meant that a more developed 2nd industry led to a lower ESV (Figure 2a). In addition, there were a series of X factors with a relatively high range of response domains and significant influence intensities. Among them, “GDP”, “light index” and “tourism output” had a positive impact on ESV, and “industrial water consumption”, “3rdindustry output value”, “agricultural electricity consumption” and “1st industry output value” had a negative impact on ESV. The function of the relationship between “water consumption” and ESV adopted an inverted U-shaped curve. The inflection point of “water consumption” was approximately 10 kt, while ESV reached a maximum value of 810 k (Figure S2).
“Water area” was another extremely significant factor, and the areas of other types of land were all NS factors except “woodland area” (S), which displayed the lowest range in the response domain compared with other significant (S) factors. The “water area”, “woodland area” and “unused land area” had a positive impact on ESV (Table 2). In contrast, the “cultivated area” and “construction land area” had a negative impact on ESV. Moreover, the relationship between the “grassland area” and ESV displayed a U-shaped curve that had an inflection point at approximately 80% of the grassland area (Figure 2b and Figure S2).
Other factors had a relatively low range of response domains, which meant that their influence was not significant. However, the functions capturing the relationship between these NS factors and ESV almost all assumed a U-shaped curve or an inverted U-shaped curve (Figure 2b and Figure S2). All the analyses suggested that there is a response relationship between ESV and socioeconomic conditions. Therefore, the ESV can be improved indirectly by adjusting these factors. However, understanding how to regulate and control the above factors to achieve a balance between ESV and economic development still requires further multifactor coupling research.