Assessment and forecast of the water-related nature’s contributions to people on the Loess Plateau from a spatial flow perspective

Integrating the spatial flow perspective, temporal trade-off perspective, and future tendency perspective enables a comprehensive assessment of nature’s contributions to people (NCPs). However, assessments that integrate these perspectives and combine them with regional ecological restoration policy remain limited. Based on the perspective of spatial flow and considering the two dimensions of nature’s contributions and people’s needs, we assessed and forecasted water-related NCPs, including water yield (NCP6), water purification (NCP7), and soil conservation (NCP8), from the Loess Plateau to downstream regions of the Yellow River in China. To forecast the future tendencies of the NCPs and their temporal trade-offs, we simulate land use changes based on rapid landscape restoration and slow landscape restoration under five shared socioeconomic pathways (SSPs) from 2020 to 2100. The results showed that the spatial distributions of the values of the three NCPs differ greatly from the corresponding values of nature’s contributions. The soil conservation NCP and water purification NCP will decrease under all scenarios, while the water yield NCP will be stable in most of the scenarios except SSP3. The soil conservation NCP showed a faster decrease under R2 compared to R1, with the highest rate observed at 2.11%. Conversely, the water purification NCP and water yield NCP experienced a faster decrease under R1 than under R2, with rates of 8.61% and 14.30% respectively. The rapid landscape restoration will have a more positive impact on the soil conservation NCP, and a more negative impact on the other two water-related NCPs than the slow landscape restoration. This assessment provides a forecast of the future benefits of landscape restoration from dual dimensions of nature’s contributions and people’s needs, indicating the importance of integrating the future changes in both dimensions when making regional landscape restoration policy.