## 3 Results  
### Temporal Changes in ESV  
#### 3.1.1 Changes in Total ESV  
The changes in the total value of ecosystem services are closely related to the dynamic shifts in land use types during the study period. From 1991 to 2021, the ESV of water bodies was much higher than that of other land use types, followed by that of cultivated land and woodland, with the sum of ESVs of these three land use types accounting for more than 95% of the total ESV, indicating the pivotal role of water bodies, cultivated land, and forests in maintaining the stability of the ecosystem along the Beijing-Hangzhou Grand Canal. The distribution of land use areas along the canal was considered (Table 3). Cultivated land ecosystems occupy a significant portion, accounting for over 60% of the entire study area, making it the primary land use type in the region, followed by forests and construction land. The water body accounted for a smaller proportion of the area than woodland, cultivated land, and construction land, but had a higher ESV. The increase in the total ESV from 1991 to 2006 was mainly due to the increase in the area of the water body, and the decrease in the ESV from 2006 to 2021 was attributed to the rapid economic development in the region, the accelerated urbanization process, and the significant increase in construction land, resulting in continued reductions in cultivated land, woodland, grassland, and water body areas.  
From 1991 to 2021, the ESV along the Beijing-Hangzhou Grand Canal exhibited a significant fluctuating trend of increasing first and then decreasing, with an overall decrease of CNY 16.684 billion. Among them, the ESVs of cultivated land and grassland continuously declined, reflecting the weakening of the ecological service supply capacity of these two land use types. The ESV of forest land experienced a slight increase and then gradually declined, eventually stabilizing at a level of CNY 233.851 billion. Although the ESV of water bodies first increased significantly and then decreased, it still showed an overall growth trend (Table 4). From 1991 to 2006, the ESV increased by CNY 46.916 billion, reaching its highest total value in 2006, with an increase of 4.83%. The ESV of water bodies experienced the largest change, with an increase of CNY 72.642 billion, accounting for 99.68% of the total increase in value during this period. From 2006 to 2021, the ESV decreased by CNY  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**1991**} & \multicolumn{2}{c}{**2006**} & \multicolumn{2}{c}{**2021**} \\ \cline{2-7}
**Land Use Type** & **ESV (CNY** & **Area of Land** & **ESV (CNY** & **Area of Land** & **ESV (CNY** & **Area of Land** \\  & **100 Million)** & **Use Type (km\({}^{2}\))** & **100 Million)** & **Use Type (km\({}^{2}\))** \\ \hline Cultivated land & 2454.20 & 140,093.63 & 2241.60 & 127,958.19 & 2095.35 & 119,609.48 \\ Woodland & 2351.04 & 26,081.39 & 2353.39 & 26,107.48 & 2338.51 & 25,942.32 \\ Grassland & 173.03 & 2591.98 & 126.05 & 1888.28 & 90.62 & 1357.50 \\ Water body & 4729.23 & 12,518.13 & 5455.65 & 14,440.94 & 5016.32 & 13,278.05 \\ Wetland & 0.07 & 0.32 & 0.06 & 0.29 & 0.06 & 0.28 \\ Construction land & 0.00 & 20,524.04 & 0.00 & 31,455.06 & 0.00 & 41,763.04 \\ Unused land & 0.15 & 164.20 & 0.11 & 123.46 & 0.02 & 23.02 \\ Total ESV & 9707.72 & 201,973.69 & 10,176.88 & 201,973.69 & 9540.88 & 201,973.69 \\ \hline \hline \end{tabular}
\end{table}
Table 3: ESVs of individual land use types along the Grand Canal from 1991 to 2021.  
63.6 billion or 6.25%. The ESVs of water bodies and cultivated land changed greatly, with a total decrease of CNY 58.558 billion.