Distinguishing ecological outcomes of pathways in Grain for Green Program in the subtropical areas of China

Effective forestation policies are urgently required across the globe under the initiative of UN Decade on Ecosystem Restoration. Rather than simply planting trees, such initiatives involve complex components of societal and biophysical systems. However, the underlying pathways by which forestation influences the ecological outcomes are not well understood, especially lacking a unified quantification framework. In this study, such a framework was developed to reveal the pathways in which reforestation programs influenced ecological outcomes through identifying the linkages among reforestation efforts, societal changes, land system changes, and ecological outcomes. The framework was applied in the reforestation program of Grain for Green Program (GFGP), to explore that how the GFGP influenced vegetation dynamics and ecosystem functioning in Guizhou Province of China through direct and indirect pathways. Two independent remote-sensing-based indicators: the enhanced vegetation index (EVI), derived from Moderate Resolution Imaging Spectroradiometer (MODIS), and gross primary production (GPP), obtained from the Solar-induced chlorophyll fluorescence (SIF) fine resolution dataset GOSIF, were combined with inventory data and land use maps to detect changes in social and ecological outcomes. Using the Structural Equation Model (SEM) to perform the framework, the results showed that the GFGP positively contributed to the increasing greenness and GPP of the study area through the direct conservation pathway. Although the implementation of GFGP encouraged outmigration and led to a decrease in farmland area, GFGP on greenness and GPP showed negative indirect effects because of the difficulty of reforestation during land-use conversion from farmland to forest land. This study revealed divergent impacts of the reforestation program through multiple pathways, which could provide valuable information for other parts of the globe to design ecological restoration policies more precisely.

The Grain for Green Program Intensifies Trade-Offs between Ecosystem Services in Midwestern Shanxi, China

Ecological engineering is a widely used strategy to address environmental degradation and enhance human well-being. A quantitative assessment of the impacts of ecological engineering on ecosystem services (ESs) is a prerequisite for designing inclusive and sustainable engineering programs. In order to strengthen national ecological security, the Chinese government has implemented the world’s largest ecological project since 1999, the Grain for Green Program (GFGP). We used a professional model to evaluate the key ESs in Lvliang City. Scenario analysis was used to quantify the contribution of the GFGP to changes in ESs and the impacts of trade-offs/synergy. We used spatial regression to identify the main drivers of ES trade-offs. We found that: (1) From 2000 to 2018, the contribution rates of the GFGP to changes in carbon storage (CS), habitat quality (HQ), water yield (WY), and soil conservation (SC) were 140.92%, 155.59%, −454.48%, and 92.96%, respectively. GFGP compensated for the negative impacts of external environmental pressure on CS and HQ, and significantly improved CS, HQ, and SC, but at the expense of WY. (2) The GFGP promotes the synergistic development of CS, HQ, and SC, and also intensifies the trade-off relationships between WY and CS, WY and HQ, and WY and SC. (3) Land use change and urbanization are significantly positively correlated with the WY–CS, WY–HQ, and WY–SC trade-offs, while increases in NDVI helped alleviate these trade-offs. (4) Geographically weighted regression explained 90.8%, 94.2%, and 88.2% of the WY–CS, WY–HQ, and WY–SC trade-offs, respectively. We suggest that the ESs’ benefits from the GFGP can be maximized by controlling the intensity of land use change, optimizing the development of urbanization, and improving the effectiveness of afforestation. This general method of quantifying the impact of ecological engineering on ESs can act as a reference for future ecological restoration plans and decision-making in China and across the world.

Effects of the “Grain for Green” Program on Soil Water Dynamics in the Semi-Arid Grassland of Inner Mongolia, China

The Grain for Green Program (GGP) initiated by Chinese government significantly impacts mitigating environmental degradation. Soil water resources probably constrain large-scale vegetation restoration projects in arid and semi-arid regions. Characterizing soil water dynamics after the GGP’s implementation is essential in assessing whether vegetation restoration can be sustained as part of ecological restoration. In this study, four sites were selected for field investigation: original natural grassland (NG) and grassland that was reconverted from cropland 12 years (12-year site), 8 years (8-year site), and 6 years (6-year site) before. Soil water at five depths was measured continuously at 10 min intervals at four sites. The findings showed that less rainfall infiltrated a deeper soil layer as the time after restoration augmented, and the 12-year site had the shallowest infiltration depth and soil water storage. Younger restored grassland (8-year and 6-year sites) had a higher soil water content than older restored grassland (12-year site) and NG. The soil water content decreased steadily with restoration age after an immediate initial rise, and the highest soil moisture was in the 8-year site. The results suggest that soil water dynamics varied with GGP and a soil water deficit could be formed after the GGP’s implementation for 12 years in semi-arid grassland.