Sustaining or enhancing Nature's Contributions to People (NCP) should highlight two aspects: nature's contributions and people's needs. However, the two aspects for water-related NCPs are spatially mismatched. We have developed an assessment framework for water-related NCPs from a spatial flow perspective, considering the  local nature's contributions assessed by the InVEST model, as well as people's needs in the downstream assessed by a distance decay method. We assessed three water-related NCPs on the Loess Plateau from 2000 to 2020, where a largescale ecological restoration was implemented. The results demonstrate that NCP6 did not show an increasing trend in most watersheds over the past 20 years, in contrast to NCP7 (from water purification) and NCP8 (from soil conservation). There are synergic relationships among NCP6 (from water yield), NCP7, and NCP8. Between 2000 and 2020, the degree of synergy between NCP7 and NCP8 increased, and between NCP6 and NCP7, as well as NCP6 and NCP8 decreased. The temporal dynamics of NCP6 and NCP8 demonstrate a trade-off relationship, whereas NCP6 and NCP7 show a synergic relationship. NCP7 and NCP8, in turn, exhibit a transition from collaboration to trade-off. Most watersheds with a correlation between the three nature's contributions and people's needs exhibited low levels or a surplus in supply. This assessment can provide guidance for planning ecological conservation and restoration in the upstream based on people's needs in the downstream.
 

生态系统服务,空间流动,距离衰减,自然的贡献,人类需求