The Loess Plateau (LP) is one of the most fragile eco-regions in China, and is characterized by severe soil erosion and water shortage. The fragile environment poses a threat to ecological safety and sustainable development on the LP and neighboring areas. The ecosystem on the LP has undergone great changes in recent decades owing to dramatic climate change, ecological rehabilitation, and tremendous human pressure. This study was focused on quantifying and assessing the multiple ecosystem services from 2000 to 2012, based on actual observation records and widely used biophysical models. These included Universal Soil Loss Equation (USLE), Revised Wind Erosion Equation (RWSQ), Carnegie-Ames-Stanford Approach (CASA), and rainfall storage method. Furthermore, in this study, the roles of climate variability and an ecological restoration program on vegetation activity and ecosystem services were investigated, as well as the synergies between multiple ecosystem services. The slight increase in both precipitation and temperature during 2000–2012, in conjunction with ecological rehabilitation, induced a trend of increasing in vegetation cover and productivity. During 2000–2012, the overall soil retention function was slightly enhanced while the amount of hydrological regulation decreased. The biomass production (vegetation carbon sequestration) and food production increased sharply. The increasing precipitation intensified water erosion by enhancing rainfall erosivity, whereas the reduction in wind speed lessened wind erosion and thereby reduced the frequency and duration of sandstorm events. Vegetation restoration supported by climate variability and resulting from ecological projects also played positive roles in soil retention enhancement. The spatial correlation analyses indicated synergies between multiple regulating ecosystem services. There was also a synergy between food production and carbon sequestration in vegetation. The performance of ecological rehabilitation and changes in ecosystem services on the LP exemplified the need for ecological conservation to take climate variability into account, and to facilitate synergies involving multiple ecosystem services, to maximize human well-being and preserve natural ecosystems.
The comprehensive control measures of the Grain for Green Program (GFGP) since 1999 included return- ing farmland to forest, artificial reforestation, closing hillsides to facilitate afforestation, grassland restoration, and other ecologi- cal rehabilitation measures, which thus compressed farmland and enlarged woodland.
|Climate change impacts||Effect of Nbs on CCI||Effect measures|
|Other climate impact||Positive||Other = Sandstorm Measure = Sandstorm prevention, estimated using revised wind erosion equation(RWEQ). Sandstorm prevention refers to the sand retained in an ecosystem within a certain period (one year for this study).|
|Other climate impact||Unclear results||OTH = hydrological regulation rainfall storage method to assess the hydrological regulation of the ecosystem - calculate the total regulated flow (m3) of a regional ecosystem compared with bare soil|
|Soil erosion||Positive||Soil retention ( t hm−2 yr−1) - through universal soil loss equation|
The Loess Plateau covers an area of approximately 6.4 × 105 km2 (34–41◦ N, 98–114◦E), traversed by the upper-middle reach of China’s Yellow River, which encompasses more than eight sub-basins