Recent advances in land-use modelling techniques may help city planners identify sites for the conservation of urban green space and the development of climate adaptation measures.
Apart from the recreational and aesthetic value they offer residents, metropolitan green spaces provide several important ecosystem services; they improve air and water quality, generate and restore soil fertility, moderate extreme temperature fluctuations, and provide wildlife habitat. Each of these functions also plays a role in climate-change adaptation.
Most metropolitan areas contain open green spaces and, while many of these are fragmented by urban expansion, they still carry significant ecological potential if developed in the right way. To determine how such areas might be best used, it is helpful to measure their level of fragmentation – how broken-up they are into separated patches – as well as certain other biophysical features such as evapotranspiration levels – the combined water loss from both surface evaporation and plant transpiration.
Recently, Italian researchers developed a new method which combines both evapotranspiration and fragmentation analysis into a single useful tool: the Land Use Suitability Strategy Model (LUSSM). By combining these two important measurements, the LUSSM can be used by planners to make better-informed decisions about land allocation.
Evaluating open spaces in terms of fragmentation and evapotranspiration is crucial for land-use planning because these measurements can go a long way toward recommending certain land uses over others. Whether a site should become a natural park, greenbelt, agricultural allotment or playground is largely a question of how fragmented it is in proportion to its evapotranspiration levels.
Good candidates for natural parks, for instance, show little fragmentation and high levels of evapotranspiration, as this indicates the presence of an intact ecosystem. The inverse is true for small gardens and playgrounds which neither require contiguous distribution nor benefit from pre-existing vegetation.
The LUSSM was tested recently in the Italian municipality of Mascalucia in the Province of Catania, Sicily. Mascalucia has seen much of its open areas, including farmland, severely impacted by urban sprawl. The model helped determine the most productive use of the remaining open space with a view to climate adaptation.
The Mascalucia trial is one of several case studies which have contributed to the Green and Blue Space Adaptation for Urban Areas and Eco Towns (GRaBS) project. Financed by the European Regional Development Fund, the project is one of several organised efforts across Europe aimed at integrating climate-change adaptation strategies into regional planning and development.
No technological change alone can secure the adaptive capacity of a city. That will depend, too, on political will. For regional authorities interested in taking a strategic approach to pollution reduction and climate change, the LUSSM may prove to be a useful tool.