近 40 年来黄土高原植被变化趋势及其生态效应.

Since 1999, China has implemented the Grain for Green Project(GFGP), which has significantly changed the vegetation coverage status and land use structure of the Loess Plateau. As a result, vegetation coverage and ecological quality have been greatly improved. However, the spatio-temporal trend of the vegetation coverage is very uncertain, while the comprehensive assessment of its ecological effects has been relatively weak. To this end, two vegetation indices, including normalized difference vegetation index(NDVI)and fractional vegetation cover(FVC), were analyzed, and the changes in vegetation coverage and distribution on the Loess Plateau before and after the implementation of GFGP in the past forty years were reviewed. The results show that ① comparing five common data sets that record the dynamic changes of vegetation coverage, it is found that the data sources affect the authenticity of the eco-environmental benefits' evaluation results to a certain extent; ② the overall vegetation coverage of the Loess Plateau has been increasing in a fluctuating manner over the years, whose growth rate has surged due to the implementation of the project; its spatial distribution decreases from southeast to northwest, and is influenced by the ecosystem pattern, land use type, climate change, etc.; ③ with a rise of vegetation coverage, the water and soil conservation, and carbon sequestration capacity of the Loess Plateau ecosystem also gradually make a build-up, both of which are highly coupled with vegetation changes. According to the current situation of eco-environment management and food production level, it is recommended to strengthen the construction of high-standard farmland to alleviate the problem of arable land shortage caused by GFGP. Meanwhile, it is necessary to accelerate the promotion of ecological value transformation and eco-compensation, so that the lucid water and lush mountains can truly become invaluable assets. [ABSTRACT FROM AUTHOR]