Exploring the response of trade-offs and synergies among ecosystem services to future land use changes in the hilly red soil region of Southern China.

Studies on the potential disruptions that future land use changes may have on trade-offs and synergies among ecosystem services (ESs) in the ecologically fragile region of hilly red soil region (HRSR) are still lacking. We employed multi-source observational data to project the land use patterns expected for the year 2035 in Jiangxi Province - a typical HRSR in China - across three specific scenarios: nature development (ND), economic development (ED), and ecological protection (EP). Through the integration of the InVEST model, correlation analysis, and geographically weighted regression methods, we evaluated habitat quality, soil conservation, water yield, and soil conservation, as well as the associated trade-offs/synergies among ESs. The results showed that the built-up land will continue to increase and occupy a large amount of cropland and woodland, resulting in a 0.79-1.96% reduction for the above four ESs under ND scenario. Under the ED scenario, the cropland and built-up land will increase by 2.95% and 12.00%, respectively, and most of them will convert from woodland, which will reduce ESs by 1.07-1.99%. Under the EP scenario, the expansion rate of built-up land will slow down and woodland will increase by 1.55%, leading to a 0.02-1.58% increase in ESs relative to the ED and ND scenarios. In addition, there were clear trade-offs observed in the ES pairs related to the water yield, while other ES pairs showed synergies. The proportions of counties that will experience changes in trade-off intensity, synergy intensity and the direction of trade-offs/synergies are expected to be 1-31%, 1-47% and 1-37%, respectively, from 2010 to 2035 under different scenarios. The study can provide valuable insights for ecological managers in HRSR in developing land use management strategies that optimize the mutual benefits of various ESs according to local conditions.