Evaluating the supply-demand relationship for urban green parks in Beijing from an ecosystem service flow perspective

The mismatch between the spatial patterns of urban green parks (UGP) and population in urban areas is a common phenomenon in Chinese cities and elsewhere. Whether and to what extent such mismatch may impact the realization of Ecosystem Service (ES) provided by the former remain unclear. Stemming from the Ecosystem Service Flow (ESF) perspective, this paper argues that the distance-decay effects and spatial heterogeneity in the propagation process of the ESF with different conveyors may render the various types of ES demonstrating different location sensitivity in both provision and realization terms. We then present an "is-ought" framework for analyzing the supply-demand relationship of ES, which features deductively obtained ES provision potential and empirically observed ES realization, both are spatially explicitly mapped. Refined ontological and distancedecay modeling methods and mobile signaling data were introduced to implement the framework taking Beijing as a case. For the two typical types of ES in urban environments, the recreational and thermoregulating services, we find that there indeed exists under- or over-supply of ES along the center-periphery gradient of the city. The findings have policy implications for the planning and management of UGP.