## Materials and Methods
### Comprehensive Assessment Indicator System for Assessing Ecological Changes from the GGP  
To comprehensively and efficiently monitor and assess the ecological changes in the GGP region, we developed an assessment indicator system from three perspectives: ecosystem pattern, ecosystem quality, and key ecosystem services (Table 2). Ecosystem area and ecosystem conversion area, which have been used in many studies, were selected as indicators to reflect changes in the ecosystem pattern [13; 20]. As the amount and distribution of vegetation are of prime importance for terrestrial ecosystems [28], the fractional vegetation cover (FVC), leaf area index (LAI), and NPP were chosen to detect ecosystem quality. The FVC is the percentage of vegetation occupying the ground area in a vertical projection [29], while LAI is the ratio of leaf surface area to unit ground surface area [30]. The FVC and LAI parameterize the horizontal and vertical density of vegetation, respectively [31]. They are two important variables used to describe the condition of land surface vegetation, characterize ecosystem changes, and reflect the related biological and physical processes [31; 32; 33; 34]. NPP marks the first visible step of carbon accumulation [35], is a key regulator of ecological processes [36], and is an important component of net ecosystem exchange or net ecosystem productivity. It indicates the metabolism of the ecosystem [37]. Because the FVC, LAI, and NPP vary within a year, we chose the  
\begin{table}
\begin{tabular}{c c c} \hline
**Classification** & **Subregions** & **Natural Characteristics** & **Restoration Measures** \\ \hline \multirow{6}{*}{Alpines-Gorges Region in Region in Region in Southern China (AGRSC)} & \multirow{6}{*}{Plateau alpine climate, annual precipitation ranges from 500 mm to 1500 mm. High terrain, steep slopes, mainly montane cinnamon soil, poor soil on sunny slopes with water deficits, naturally poor regeneration of forest.} & \multirow{6}{*}{Return all sloping cropland above 25\({}^{\circ}\) with shallow soil to forest; forest sloping land with gentler gradient and thicker soil after partial transformation into high-standard farmland by 0.1 h a per capita. Emphasis on planting of ecological forest and appropriate development of timber and firewood forest and high-quality pasture.} \\ \cline{1-1}  & Mountains-Hills Region in Sichuan, & \multirow{6}{*}{Subtropical humid monsoon climate, annual precipitation ranges from 1000} & After guaranteeing high-standard farmland of 0.07 h per capita, replant all sloping to regional to ecological forest after partial transformation into economic forest by 0.07 h per capita. Ecological forest and timber forest should account for over 80\%, and economic forest for under 20\%. \\ \cline{1-1}  & Low Mountains-Hills Region in Middle and Lower Yangtze Plain (LMHRMLYP) & Subtropical humid monsoon climate, annual precipitation ranges from 1400 & Reforest all sloping cropland above 25\({}^{\circ}\), and sloping cropland between 15\({}^{\circ}\)-25\({}^{\circ}\) with important ecological status. Emphasis on planting ecological forest and grassland, while taking timber and economic forest into consideration. Mainly plant trees, with some shrubs and herbs. \\ \cline{1  
annual maximum value of FVC (FVC\({}_{\text{max}}\)) and LAI (LAI\({}_{\text{max}}\)) to reflect the instantaneous vegetation growth status, and the annual average value of NPP (NPPavg) to reflect the accumulated process of carbon accumulation. In addition, owing to the aims of the GGP were to control soil erosion, mitigate flooding, and prevent sandstorms, we selected three key ecosystem services, water regulation (WR), soil conservation (SC), and sandstorm prevention (SP), to evaluate the enhancement of ecosystem services arising from the program implementation. The annual quantity per unit area of water regulation (WR\({}_{\text{pua}}\)), soil water loss (SWAL\({}_{\text{pua}}\)), and soil wind loss (SWIL\({}_{\text{pua}}\)) were selected as assessment indicators to exclude the influence of area.