A Land Suitability Index for Strategic Environmental Assessment in metropolitan areas

This paper presents the Land Suitability Index (LSI), a transparent, modular hierarchical system of cartographic indices aimed at delivering Strategic Environmental Assessment (SEA) of developmental land uses for regional planning (European Directive 2001/42/EC). The LSI evaluates land suitability by combining three main sub-indices concerning (i) the vulnerability of the biosphere, lithosphere, and hydrosphere to impacts arising from implementing development proposals; (ii) the natural heritage value of the target area; and (iii) its contribution to terrestrial ecological connectivity. We have used the LSI to evaluate the impact of municipal urban plans in the Barcelona Metropolitan Region (BMR). For this case study, we provide redundancy and sensitivity analyses, and a partial validation using independent studies. Results showed noticeable inconsistencies between the municipal plans and the values of the LSI and its main sub-indices. There was moderate redundancy between sub-indices but considerable sensitivity to changes in input variables. Validation showed a high degree of coincidence with previous, independent, studies as regards connectivity. The quantitative and cartographic approach adopted by the methodology facilitates conveying the results to planners and policy makers. In addition, successive iterations to check the impact related to different alternative planning scenarios can be quickly performed. We therefore propose its application to other metropolitan areas.