Mapping and quantifying variations in ecosystem services of urban green spaces: A test case of carbon sequestration at the district scale for Seoul, Korea (1975-2015)

Abstract

Urban ecosystem services (ESs) can moderate many common environmental issues in cities that are caused by the land use transformation central to urbanization. However, quantitative knowledge of historical changes in ES provisioning at various urban scales is limited. In this research, it is proposed to identify ESs, especially those generated by urban green space (UGS), and quantify their spatiotemporal variations at the regional scale in the southern part of Seoul City, Korea. Changes are first detected in landscape patterns, then one ES indicator - carbon sequestration (CS) - is chosen as a test case, and its spatial pattern explored using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. Total potential CS decreased by 41.2% from 1975 to 2015, with loss and fragmentation of landscapes occurring and patches becoming smaller and simpler in shape in the urban area, as indicated by landscape metrics. Moreover, strong decreases in urban forest and agricultural areas were the primary causes of loss of CS. On the other hand, a 120% increase in the grassland area somewhat offset these two factors. It is hoped that these results will contribute to cognizance of the potential of historical processes to inform future policy decisions related to green infrastructure and land-use planning.