Long-term effects of restoration strategies on ecosystem functions, soil conservation and afforestation on the Loess Plateau

Loess Plateau is a typical ecologically-fragile area worldwide. Vegetation restoration acts as a long-term and important strategic program wherein, while the ecological effects after long-term vegetation restoration need to be assessed in detail to support for ecological restoration in similar areas. Across the Loess Plateau, four representative sites: the P. tabulaeformis artificial forest, P. orientalis artificial forest, R. pseudoacacia artificial forest and natural Secondary forest were selected as typical artificial plantations and natural forests in this study. To analyze ecological benefits under different vegetation restoration types and discuss the optimal model of afforestation in the future, soil properties in 0-100 cm, vegetation attributes at four synusium, hydrological processes of 23 rainfall events and ecosystem functions (10-years soil water storage) were measured and compared. The results showed that: (1) the soil properties of natural forest, especially soil water retention, were better than that of planted forests; (2) the biomass of arborous synuium in natural forest was lower than that in artificial forest, while it was significantly higher at shrub and herbaceous synuium; (3) there were differences in rainfall redistribution between natural and artificial forest with the satisfactory water storage conversion in study, but the natural forest had the highest soil water storage (414.33 mm) during the last decade; (4) according to the structure equation model (SEM), the vegetation attributes at arborous and herbaceous synuium had the most direct and total effects on the hydrological processes and function in ecosystems. The results indicate that afforestation should be conducted in a nature inclusive manner, which can provide guidance for vegetation restoration in the Loess Plateau and similar ecologically-fragile regions in the future.