Non-linearity impacts of landscape pattern on ecosystem services and their trade-offs: A case study in the City Belt along the Yellow River in Ningxia, China

[Display omitted] •Landscape pattern has significant but limited un-linearity impact on ESs.•3 km has been suggested as the most suitable scale across 1.5 km to 30 km.•Landscape-level metrics of CONTAG, SHDI and FRACMN have larger impacts than others.•Too high or low fragmentation or diversity would alter relations among ESs.•These un-linearity and threshold relations provide new direction for improving ESs. Exploring the impacts of landscape pattern on ecosystem services (ESs) and their trade-offs could provide a new way to improve ESs without largely altering land use types. Using the City Belt along the Yellow River in Ningixa (CBYN) as a case study, we quantified five critical ESs (one provision service of crop production, three regulating services of carbon sequestration, nutrient retention and sand fixation, and one cultural service of recreational opportunity) in 1989–2019 through CASA model, InVEST model and empirical equations. Then we calculated landscape pattern metrics at landscape and class level through Fragstats 4.3 across multiple scales and quantified their impacts on each ES and ES trade-offs through random forest analysis, self-organizing mapping analysis and multivariable regression tree. The results suggested that 3 km is more suitable for analyzing the impacts of landscape pattern on ESs in the CBYN. The nonlinear relations between landscape pattern metrics and each ES were fitted with adjusted R2 ranging from 0.26 to 0.51, indicating the significant but limited impacts of landscape pattern on ESs. Specially, landscape-level metrics of CONTAG, SHDI and FRACMN have higher impacts on ESs than class-level ones. Significant synergies existed among agricultural production, carbon sequestration and nutrient retention, except in mountain region with higher or lower fragmentation. Sand fixation has synergy relations with the former three ESs, which would be altered in situations with higher or lower diversity. Our results provide a new direction for land use management to achieve high-quality development without largely altering existing land use situation.