Indicator of connectivity: application to specific Sardinian cases

Landscape fragmentation (LF) is a process largely caused by road infrastructure and urbanised areas. LF consists of dividing a natural environment into several separate fragments and reducing the surface area of the original land. The most obvious effects are: the isolation of animal and plant species, the reduction of biodiversity, and loss of connectivity between natural areas. LF can be considered as one of the main causes that negatively affect landscape quality, because it triggers habitat loss processes, decline of fauna and flora species. Transport and mobility infrastructures and urban settlement have been acknowledged as key factors in catalysing LF processes. On the other hand, connectivity is defined as "the degree to which the landscape facilitates or prevents movement between patches” and can be measured by the probability of movement between all points or areas of intervention of a landscape. In this work we propose the application of the connectivity indicator for natural areas. The index, which is part of a more complex indicator, the City Biodiversity Index (CBI), or Singapore Index on Cities' Biodiversity Index, is particularly useful for measuring connectivity of natural areas in urban environments. This index can provide answers on the degree of connectivity of a habitat, considering intra and inter patch movement. We apply the indicator to specific case studies located in Sardinia, in the cities of Cagliari and Sassari. The connectivity between the natural areas of the urban context has been evaluated; results provide planners with powerful indications on possible interventions able to limit the effects of LF.