Associations among ecosystem services from local perspectives.

Present works on the relationship between pairwise ecosystem services (ES) in one period are mostly based on global perspective, which ignores the influence of spatial heterogeneity. In view of this problem, this study proposes a static local association model for pairwise ES, and the applicability of this model is then tested in Ningxia Hui Autonomous Region, China. Four ES, namely, grain production, livestock production, soil conservation, and carbon sequestration, are selected. The global and local associations among these services are tested and compared using Spearman's correlation analysis and the proposed local static association model, respectively. Results showed that all six possible ES pairs were significantly correlated in the global scale. However, for strongly correlated pairwise ES (e.g., grain production and livestock production and carbon sequestration), a reverse trend still exists in some local areas. This inference is especially true for ES pairs with relatively low correlation coefficient. We also determine that some of the trade-offs or synergies are formed only by artifact, such as the synergy between grain and livestock production in the midwest, the trade-off between grain production and carbon sequestration concentrating on the southern mountains, and the trade-off between livestock production and soil conservation and carbon sequestration in the central area of the northern Yellow River irrigation district. In summary, local association analysis conveys the abstract overall relationship among specific spatial locations to identify the mechanism of the relationship among ES. This finding will provide new insights for the planning and management of ES, which include that local ES cannot be managed and planned according to the global relationship, local trade-offs or synergies caused by artifact cannot be applied to ES management, the proposed local association analysis helps identify ES problems in parts, and the high-value synergy area is an appropriate reference for ecosystem management.