Open space fragmentation in Hong Kong's built–up area: An integrated approach based on spatial horizontal and vertical equity lenses

Spatial equity embeddedness in fragmented open space has long been neglected but is now becoming a pivotal topic in sustainable urban development. It is unclear whether open space fragmentation has widened existing spatial inequalities. Thus, this study proposes an integrated methodological framework of open space fragmentation and its associated spatial equity issue in towns at different stages of urbanisation development. Hong Kong's built–up area could provide a typical case to unveil this topic due to the high shortage of open space, continued urbanisation, high immigrant rate, large wealth gap and aging population. The characteristics of open space fragmentation forms in old and new towns are elaborated through landscape pattern analysis and principal components analysis. Spatial horizontal equity and spatial vertical equity based on demographic characteristics and social economic status are portrayed by means of the Theil index and spatial matching. The findings indicate that the heterogeneity of open space fragmentation is evidenced by the uneven distribution of residents' environments in the old and new towns. Statistics reveal that in addition to shape fragmentation, the mean values of use fragmentation, internal fragmentation, extensive fragmentation and location fragmentation in old towns are all larger than those in new towns. Additionally, internal fragmentation overall is embedded in more spatial horizontal inequalities, and there is a higher level of spatial horizontal inequality in old towns than in new towns. Vulnerable groups that rely more on open spaces, including children, the elder, low education groups, immigrant groups and unemployed groups, suffer more from spatial vertical inequalities in old towns than in new towns. The knowledge gained from this research could provide a valuable reference for open space planning at home and abroad.