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.

Impact of Grain for Green Project on Water Resources and Ecological Water Stress in Yanhe River Basin

Grain for Green project (GGP) initialed by China government since 1999 has achieved substantial achievements accompanied with surface runoff decrease in the Loess Plateau but impacts of large-scale afforestation on regional water resources are uncertain. Hence, the objective of this study is to explore the impact of land use change on generalized water resources and ecological water stress using blue and green water concept taking Yanhe River Basin as a case study. Soil and Water Assessment Tool (SWAT) is applied to quantify summary of green and blue water which is defined as generalized water resources, ecological water requirement of vegetation (forest and grass), agricultural water footprint and virtual water flow are considered as regional water requirements. Land use types of 1980 (scenario?), 2017 (scenario?) are input in SWAT model while keeps other parameters constant in order to isolate the influence of land use changes. Results show that average annual difference of blue, green and generalized water resources is -72.08 million m 3 , 24.34 million m 3 , -47.74 million m 3 respectively when simulation results of scenario? subtracts scenario?and it presents that land use change caused by GGP leads to decrease in blue and generalized water resources whereas increase in green water resources. SURQ in scenario?is more than that in scenario?in all the study period from 1980-2017, green water storage in scenario?is more than that in scenario? in all the study period except in 1998; whereas LATQ in scenario?is less than that in scenario? except in 2000 and 2015, GWQ in 1992, 2000 and 2015, green water flow in 1998. Blue water, green water storage and green water flow in scenario? is less than that in scenario?in the whole basin, 12.89 percent of the basin and 99.21 percent of the basin respectively. Total WF increases from 1995 to 2010 because forest WF increases significantly in this period though agricultural WF and grass WF decreases. Ecological water stress index has no obvious temporal change trend in both land use scenarios but ecological water stress index in scenario? is more than that in scenario?which illustrates that GGP leads to increase of ecological water stress from perspective of generalized water resources

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.