[1] Gerla P, Cornett M, Ekstein J et al. Talking big: Lessons learned from a 9000 hectare restoration in the northern tallgrass prairie[J]. Sustainability, 4, 3066-3087(2012).

[2] Anwar M M. Recreational opportunities and services from ecosystem services generated by public parks in megacity Karachi-Pakistan[J]. Sindh University Research Journal-Science Series, 44, 23-28(2012).

[3] Reyers B, O'farrell P J, Cowling R M et al. Ecosystem services, land-cover change, and stakeholders: Finding a sustainable foothold for a semiarid biodiversity hotspot[J]. Ecology and Society, 14, 38-61(2009).

[5] Foudi S, Spadaro J V, Chiabai A et al. The climatic dependencies of urban ecosystem services from green roofs: Threshold effects and non-linearity[J]. Ecosyst Services, 24, 223-233(2017).

[6] Peng J, Tian L, Liu Y X et al. Ecosystem services response to urbanization in metropolitan areas: Thresholds identification[J]. Science of the Total Environment, 607, 706-714(2017).

[7] Collins S L, Carpenter S R, Swinton S M et al. An integrated conceptual framework for long-term social-ecological research[J]. Frontiers in Ecology & the Environment, 9, 351-357(2011).

[8] Zhang J Z, Luo M T, Yue H et al. Critical thresholds in ecological restoration to achieve optimal ecosystem services: An analysis based on forest ecosystem restoration projects in China[J]. Land Use Policy, 76, 675-678(2018).

[9] Yang G, Zhong B B, Yue H et al. A degradation threshold for irreversible loss of soil productivity: A long-term case study in China[J]. Journal of Applied Ecology, 48, 1145-1154(2011).

[10] Cao S X, Lu C X, Yue H. Optimal tree canopy cover during ecological restoration: A case study of possible ecological thresholds in Changting, China[J]. Bioscience, 67, 221-232(2017).

[11] Fu B J, Liu Y, Lü Y H et al. Assessing the soil erosion control service of ecosystems change in the Loess Plateau of China[J]. Ecological Complexity, 8, 284-293(2011).

[12] Jiang W G, Yuan L H, Wang W J et al. Spatio-temporal analysis of vegetation variation in the Yellow River Basin[J]. Ecological Indicators, 51, 117-126(2015).

[13] Lü Y H, Fu B J, Feng X M et al. A policy-driven large scale ecological restoration: Quantifying ecosystem services changes in the Loess Plateau of China[J]. PLoS ONE, 7, e31782(2012).

[14] Xin Z B, Ran L S, Lu X X. Soil erosion control and sediment load reduction in the Loess Plateau: Policy perspectives[J]. International Journal of Water Resources Development, 28, 325-341(2012).

[15] Chen H S, Shao M A, Li Y Y. Soil desiccation in the Loess Plateau of China[J]. Geoderma, 143, 91-100(2008).

[16] Wang Y Q, Shao M A, Shao H B. A preliminary investigation of the dynamic characteristics of dried soil layers on the Loess Plateau of China[J]. Journal of Hydrology, 381, 9-17(2010).

[17] Cao S X, Chen L, Shankman D et al. Excessive reliance on afforestation in China's arid and semi-arid regions: Lessons in ecological restoration[J]. Earth-Science Reviews, 104, 240-245(2011).

[18] Wang Y Q, Shao M A, Zhu Y J et al. Impacts of land use and plant characteristics on dried soil layers in different climatic regions on the Loess Plateau of China[J]. Agricultural and Forest Meteorology, 151, 437-448(2011).

[19] Chen F, Yuan Y J, Zhang R B et al. A tree-ring based drought reconstruction (AD 1760-2010) for the Loess Plateau and its possible driving mechanisms[J]. Global and Planetary Change, 122, 82-88(2014).

[20] Cai Q G. Soil erosion and management on the Loess Plateau[J]. Journal of Geographical Sciences, 11, 53-70(2001).

[21] Bai Y, Jiang B, Wang M et al. New ecological redline policy (ERP) to secure ecosystem services in China[J]. Land Use Policy, 55, 348-351(2015).

[22] Feng X M, Fu B J, Lu N et al. How ecological restoration alters ecosystem services: An analysis of carbon sequestration in China's Loess Plateau[J]. Scientific Reports, 3, 2846(2013). https://doi.org/10.1038/srep02846

[23] Lü Y H, Zhang L W, Feng X M et al. Recent ecological transitions in China: Greening, browning, and influential factors[J]. Scientific Reports, 5, 8732(2015). https://doi.org/10.1038/srep08732

[24] Zhang K, Lü Y H, Fu B J et al. The effects of restoration on vegetation trends: Spatiotemporal variability and influencing factors[J]. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 109, 473-481(2019).

[25] Jiang Z Y, Huete A R. Linearization of NDVI based on its relationship with vegetation fraction[J]. Photogrammetric Engineering and Remote Sensing, 76, 965-975(2010).

[26] Ivits E, Cherlet M, Sommer S et al. Addressing the complexity in non-linear evolution of vegetation phenological change with time-series of remote sensing images[J]. Ecological Indicators, 26, 49-60(2013).

[27] Imukova K, Ingwersen J, Streck T. Determining the spatial and temporal dynamics of the green vegetation fraction of croplands using high-resolution RapidEye satellite images[J]. Agricultural and Forest Meteorology, 206, 113-123(2015).

[29] Deng S F, Yang T B, Zeng B et al. Vegetation cover variation in the Qilian Mountains and its response to climate change in 2000-2011[J]. Journal of Mountain Science, 10, 1050-1062(2013).

[30] Zhang Y L, Gao J G, Liu L S et al. NDVI-based vegetation changes and their responses to climate change from 1982 to 2011: A case study in the Koshi River Basin in the middle Himalayas[J]. Global and Planetary Change, 108, 139-148(2013).

[31] Fu B J, Zhao W W, Chen L D et al. Assessment of soil erosion at large watershed scale using RUSLE and GIS: A case study in the Loess Plateau of China[J]. Land Degradation & Development, 16, 73-85(2005).

[32] Wischmeier W H, Smith D D. Predicting Rainfall Erosion Losses: A Guide to Conservation Planning[J]. Washington, DC: United States Department of Agriculture(1978).

[33] Sharpley A N, Williams J R. EPIC-erosion/productivity impact calculator: Model documentation[J]. Technical Bulletin-United States Department of Agriculture, 329, 421-428(1990).

[34] Mccool D, Brown L, Foster G et al. Revised slope steepness factor for the universal soil loss equation[J]. Transactions of the American Society of Agricultural and Biological Engineers, 30, 1387-1396(1987).

[35] Zhang L W, Fu B J, Lü Y H et al. Balancing multiple ecosystem services in conservation priority setting[J]. Landscape Ecology, 30, 535-546(2015).

[36] Zhang L, Dawes W R, Walker G R. Response of mean annual evapotranspiration to vegetation changes at catchment scale[J]. Water Resources Research, 37, 701-708(2001).

[37] Lü N, Sun G, Feng X M et al. Water yield responses to climate change and variability across the North-South Transect of Eastern China (NSTEC)[J]. Journal of Hydrology, 481, 96-105(2013).

[38] Hamon W R. Computation of direct runoff amounts from storm rainfall[J]. International Association of Hydrological Sciences Publication, 63, 52-62(1963).

[39] Lu J B, Sun G, Mcnulty S G et al. A comparison of six potential evapotranspiration methods for regional use in the southeastern united states[J]. Journal of the American Water Resources Association, 41, 621-633(2005).

[40] Li M, Yao W Y, Ding W F et al. Effect of grass coverage on sediment yield in the hillslope-gully side erosion system[J]. Journal of Geographical Sciences, 19, 321-330(2009).

[41] Zheng F L. Effect of vegetation changes on soil erosion on the Loess Plateau[J]. Pedosphere, 16, 420-427(2006).

[42] Feng X M, Sun G, Fu B J et al. Regional effects of vegetation restoration on water yield across the Loess Plateau, China[J]. Hydrology and Earth System Sciences, 16, 2617-2628(2012).

[43] Fu B J, Wang S, Liu Y et al. Hydrogeomorphic ecosystem responses to natural and anthropogenic changes in the Loess Plateau of China[J]. Annual Review of Earth and Planetary Sciences, 45, 223-243(2017).

[44] Sun Q H, Miao C Y, Duan Q Y et al. Temperature and precipitation changes over the Loess Plateau between 1961 and 2011, based on high-density gauge observations[J]. Global and Planetary Change, 132, 1-10(2015).

[45] Deng L, Kim D G, Li M et al. Land-use changes driven by 'Grain for Green' Program reduced carbon loss induced by soil erosion on the Loess Plateau of China[J]. Global and Planetary Change, 177, 101-115(2019).

[46] Wang Y Y, Deng L, Wu G L et al. Estimates of carbon storage in grassland ecosystems on the Loess Plateau[J]. Catena, 164, 23-31(2018).

[47] Zhang J, Ding Z, Luo M. Risk analysis of water scarcity in artificial woodlands of semi-arid and arid China[J]. Land Use Policy, 63, 324-330(2017).

[48] Martin J, Runge M C, Nichols J D et al. Structured decision making as a conceptual framework to identify thresholds for conservation and management[J]. Ecological Applications, 19, 1079-1090(2009).