An Infrastructure Fragmentation Index for Assessing Landscape Fragmentation Due to Transportation Infrastructure

Landscape fragmentation is the phenomenon of breaking up natural areas into smaller, more isolated units. The present work describes a methodology for evaluating the impact of both new and pre-existing transportation infrastructures by means of land cover maps. It enables quantifying the “pressure” on natural areas in terms of any further reduction in suitable habitat units based on the type of infrastructure and land cover elements. The proposed Infrastructural Fragmentation Index (IFI) assesses landscape fragmentation, taking into account both the number and connectivity of natural areas, which are rendered in clusters. The effects of defragmentation measures, such as wildlife crossings, are evaluated in terms of the consequent reduction in the pressure from the infrastructure. A case study has been analyzed in order to evaluate the fragmentation effects due to a new motorway in Lombardy (Italy), using CLC2000 and a GIS. Three scenarios have been studied: in the absence of the new infrastructure, and in its presence without and with the addition of wildlife crossings.