An indicator set for capturing long-term open space fragmentation and urban development dynamics

Open space preservation is an important spatial policy issue in developed, densely populated countries. Understanding open space dynamics in relation to urban development is critical to the development and evaluation of such policies. Starting from a conceptual model that hypotheses how open space will have developed over the past century we use a set of landscape ecology based indicators to capture these changes from a societal (perceptional) perspective. The indicators are applied to a newly compiled geodatabase of urban development in the Netherlands to show their performance in detecting and understanding past and future trends in open space provision. Our combined indicator set consists of land-use-based metrics that capture the area ratio of open space in relation to the total available space and total unit density of open and built-up patches. The methodology is designed to fit the low spatial and thematic resolution of land-use models as is exemplified by the inclusion of a future land-use scenario in the evaluation of open space development. The indicators confirm the hypothesised intrusion, intermediate and fill-up phases in open space fragmentation, and indicate a strong correlation between fragmentation and loss of open area. The results facilitate the distinguishing of compact urban regions from more fragmented counterparts while taking their relative state of urban development into account. The combined indicator set is useful to summarise and compare spatial development status between regions, while in combination with the advent of more detailed historic land-use data, our approach can be used to analyse open-space dynamics in different socioeconomic contexts.