## 2 Study Area, Data and Methodology
### Estimation of ESV  
[PERSON] et al. [1] proposed an ESV accounting method based on the classification of ecosystems and service functions and estimated the global ESV. Based on [PERSON] et al. 's parameters, [PERSON] et al. [22] extracted the ESEV and modified the value coefficients of the Chinese terrestrial ecosystem. With deeper research, [PERSON] et al. [24] supplemented the ESEV according to different types of literature research and ecological monitoring data and proposed an integrated method for evaluating the ESEV in a unit area for different ecosystem types and different ecosystem service functions on Chinese terrestrial ESV. Based on the 2010 ESEV proposed by [PERSON] et al. [24], this paper adjusts it into Table 2 as the basic reference standard. In the Table 2, the provisioning services include food production (FP), raw material production (RMP) and water provision (WP); the regulation services include gas regulation (GR), climate regulation (CR), environmental purification (EP) and hydrology regulation (HR); the supporting services include soil formation and retention (SFR), nutrition circulation (NC) and biodiversity protection (BP); and the culture services mainly manifest as aesthetic scenery (AS). (Note: Considering that the study area is located in the tropical monsoon climate area, cropland is dominated by paddy fields, so the ESEV of cropland adopts paddy fields. In the original paper [24], the WP of the paddy field is negative, but in fact the study area has abundant rainfall, in addition to the water resources consumed by the paddy field itself, the paddy field can still generate a net water provision, so we adjusted the WP of the paddy field ESEV to 0.02). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Function**} & \multirow{2}{*}{**Cropland**} & \multirow{2}{*}{**Orchard**} & \multirow{2}{*}{**Forest**} & \multirow{2}{*}{**Grassland**} & \multicolumn{2}{c}{**Unused and**} & \multirow{2}{*}{**River**} & \multicolumn{1}{c}{**Wetland and**} \\  & & & & & & **Other** & & **Lakes** \\ \hline FP & 1.36 & 1.035 & 0.29 & 0.38 & 0 & 0.44 & 0.51 \\ RMP & 0.4 & 0.61 & 0.66 & 0.56 & 0 & 0.23 & 0.5 \\ WP & 0.02 & 0.325 & 0.34 & 0.31 & 0 & 3.12 & 1.32 \\ GR & 1.11 & 2.07 & 2.17 & 1.97 & 0.02 & 0.77 & 1.1 \\ CR & 0.57 & 5.855 & 6.5 & 5.21 & 0 & 2.29 & 3.6 \\ EP & 0.17 & 1.825 & 1.93 & 1.72 & 0.1 & 2.55 & 2.6 \\ HR & 2.72 & 4.28 & 4.74 & 3.82 & 0.03 & 20.8 & 14.23 \\ SFR & 1.03 & 2.525 & 2.65 & 2.4 & 0.02 & 0.66 & 1.2 \\ NC & 0.12 & 0.19 & 0.2 & 0.18 & 0 & 0.07 & 0.18 \\ BP & 0.13 & 2.295 & 2.41 & 2.18 & 0.02 & 1.88 & 3.32 \\ AS & 0.06 & 1.01 & 1.06 & 0.96 & 0.1 & 0.66 & 2.73 \\ Total & 7.69 & 22.02 & 22.95 & 19.69 & 0.29 & 33.47 & 31.29 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Basic reference standard ecosystem service equivalent value (ESEV) table [24]. Ecosystem service capacity refers to the capacity to provide ecosystem products and services in specific areas over a specific time period. Ecosystems and their services have significant spatial heterogeneity and interannual differences, so their service capabilities also have significant spatial and temporal differentiation characteristics. Considering the difference between the national parameter representation area and the interannual ecological background quality characteristics, it was necessary to modify China's nationwide ESEV. The food production and raw material production services were quantitatively modified by the crop production coefficients (CPCs), which were calculated from the unit area output of rice, beans and potato food crops in the national and Guangdong statistical yearbooks. These crops are the main food crops both in the nation and in the study area. The _CPC_ calculation is shown in Equation (1):  
\[\left\{ \begin{aligned} & CPC=\frac{Production_{r}\ +\ Production_{b}\ +\ Production_{p}}{Total_{Area}}\\ &\eta_{Food\ \&\ Material}\ =\ \frac{ CPC_{GDyr}}{\ CPC_{CHNyr}}.\frac{ CPC_{CHNyr}}{ CPC_{CHN2010}}\end{aligned} \right.