Modelling the fragmentation of open space. A framework for assessing the impact of land use change on open space

The Netherlands is one of the most densely populated countries in the world and urban functions are constantly claiming more space. This continuing urbanisation has lead to a growing concern for the preservation of open space. A loss of open space does not only mean a fragmentation of ecosystems or (potential) animal habitat but also affects the geographical, historical and cultural qualities of the landscape. The preservation of open space is an important theme in the spatial planning of the Netherlands. The Dutch government strives to keep the total volume of open space at a reasonable high level and tries to avoid the fragmentation of open space. The present research deals with the modelling of future land use and will focus more specifically on the fragmentation of open space. A GIS-oriented land use model will be used to study this subject. Assessing the impact of land use change on open space calls for a thorough definition of open space that takes into account the shape and size characteristics of various land use functions. This definition is strongly related to the policy context that introduces the concept of open space. In the Dutch, anthropocentric practice open space does not necessarily refer to large natural areas with high ecological values, but it rather relates to large areas with relatively few buildings. This might for example exclude wooded areas that do not offer panoramic views. Single objects (high voltage or television masts) can also severely affect the individual experience of open space. GIS-technology allows for a quantitative implementation of the concept of open space. It furthermore facilitates the spatial analysis of the impact of land use changes. Different simulations from land use models will be assessed both in terms of a total loss in the volume of open space and the localised impact in terms of fragmentation. To study the latter impact a methodology will be developed that will adopt experiences from spatial ecological research on habitat fragmentation.