Separating the effects of two dimensions on ecosystem services: Environmental variables and net trade-offs

Spatial and temporal changes in ecosystem services (ESs) are driven by two types of factors: environmental factors and trade-offs/synergies between services. In the ecological conservation red line (ECRL) area, in which national ecological security and social sustainable development are guaranteed, it is particularly important to clarify the driving mechanism of ESs for the management of ecosystems. In this study, soil conservation, water yield, and carbon sequestration in Beijing’s ECRL area are quantified, and GeoDetector is used to identify the factors influencing the trade-offs/synergies between ESs. Moreover, partial correlation analysis is used to calculate the net trade-offs/synergies and compare them with the extent to which environmental variables contribute to ESs. The results are as follows: environmental variables and trade-offs/synergies have different effects on the changes in ESs, and their interactions can enhance the determinative power of the corresponding individual variable. The land use intensity is an extremely important factor affecting the trade-offs/synergies between the three services, indicating that rational land use planning in Beijing’s ECRL area is crucial for avoiding the negative impacts of trade-offs and enabling coordinated optimization of ESs. After the elimination of the cross-influence of environmental variables, the trade-offs/synergies change significantly, and the impact of environmental variables on ESs is compared with the net trade-offs/synergies. Environmental variables are the driving forces of the spatiotemporal changes in soil conservation. Precipitation and carbon sequestration have similar effects on water yield. Spatiotemporal changes in carbon sequestration are closely related to the other two services, with smaller influences from environmental variables.