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Highlights • We quantified the soil erosion change in a spatially explicit manner. • We investigated the driving forces of soil erosion change. • The hydrological effects of soil and water conservation were assessed. • The limitations and sustainability of soil and water conservation were discussed. Abstract Land degradation is a global environmental problem that threatens human safety and socioeconomic development. In order to alleviate severe soil erosion, China has implemented historically unprecedented large-scale afforestation. In this study, we selected the most severely eroded Loess Plateau as a case, to assess the effectiveness of soil and water conservation (SWC) efforts based on the Revised Universal Soil Loss Equation. In addition, the underlying drivers for soil erosion changes and hydrological effects of SWC were investigated, and finally the potential policy implications of our findings were discussed. The soil erosion intensity from 2000 to 2015 was weakened largely due to favorable climate conditions and SWC efforts, which promoted vegetation restoration and enhanced soil retention. However, there was a significant trade-off between water provision and soil retention functions. The excessively artificial afforestation reduced sediment yield but depleted surface runoff. Furthermore, artificial afforestation and increasing irrigation water consumption overused groundwater resources and finally lowered groundwater table. The SWC efforts characterized by artificial afforestation induced soil moisture declining, particularly for the conversion type of farmland to forest/shrub. Our results suggested that afforestation might be a poor choice in arid and semiarid regions, because it did not consider local precipitation conditions, and have exacerbated water shortages and offset SWC efforts. Therefore, the future ecological restoration efforts should be transformed from simple species-based measures to optimal plant species combinations to minimize the tradeoff between water yield and soil retention. The strategies for ecological restoration of drylands should also account for water balance to ensure effectiveness and sustainability. [ABSTRACT FROM AUTHOR]

Human demands for natural resources have significantly changed the natural landscape and induced ecological degradation and associated ecosystem services. An understanding of the patterns, interactions, and drivers of ecosystem services is essential for the ecosystem management and guiding targeted land use policy-making. The Losses Plateau (LP) provides ecosystem services including the carbon sequestration and soil retention, and exerts tremendous impacts on the midstream and downstream of the Yellow River. Three dominant ecosystem services between 2000 and 2012 within the LP were presented based on multiple source datasets and biophysical models. In addition, paired ecosystem services interactions were quantified using the correlation analysis and constraint line approach. The main conclusions are as follows. It was observed that the warming and wetting climate and ecological program jointly promoted the vegetation growth and carbon sequestration. The increasing precipitation throughout 2000–2012 was related to the soil retention and hydrological regulation fluctuations. The vegetation restoration played a positive role in the soil retention enhancement, thus substantially reduced water and sediment yields. The relationships between ecosystem services were not only correlations (tradeoffs or synergies), but rather constraint effects. The constraint effects between the three paired ecosystem services could be classified as the negative convex (carbon sequestration vs. hydrological regulation) and hump-shaped (soil retention vs. carbon sequestration and soil retention vs. hydrological regulation), and the coefficients of determination for the entire LP were 0.78, 0.84, and 0.65, respectively. In the LP, the rainfall (water availability) was the key constraint factor that affected the relationships between the paired ecosystem services. The spatially explicit mapping of ecosystem services and interaction analyses utilizing constraint line approach enriched the understanding of connections between ecosystem services and the potential drivers, which had important implications for the land use planning and landscapes services optimizing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]