The greenspace in urban settlements provides city citizens with immediate access to greenness and numerous ecosystem services, as urban residential greenspace comprises more than half of overall greenspace in many cities. Their small patch size and high biodiversity, however, bring more challenges for low- and moderate-resolution satellite imagery to accurate greenspace mapping, which could help authorities better manage greenspace to support human well-being.
Here we conducted residential greenspace recognitions at two different scenarios and scales. Firstly we recognized greenspace types in urban settlements of Leuven city, Belgium using multi-temporally stereoscopic Pleiades satellite imagery. We found that the mean green coverage of urban gardens was 62.37% (mean green size was 366m²) across the study area of Leuven city. The overall accuracy achieved by multi-temporal imagery was nearly 9.47%, tri-stereo imagery for 12.79%, and was up to 20.16% when applying them together. Then we quantified the residential greenspace dynamics from 1995 to 2010 across European human settlements. From the continental analysis, we concluded that the moderate resolution satellite imagery dramatically underestimated the greenspace growth in European human settlements. The residential greenspace per capita was divergent among European countries. Most southern European settlements exhibit the degradation of residential greenspace while eastern Europe was almost the opposite. Developing high-vegetated new settlements has been the primary way to increase their urban greenness level for most European countries. This study calls for greater attention to urban residential greenspace and more multidisciplinary studies conducted in collaboration of local authorities and urban ecologists to provide both greenspace density and landscape amenities in urban human settlements.
 

城市居民区,城市绿地,遥感,人类福祉