Urban-rural ecological networks and landscape planning

Urban-rural landscape planning research is nowadays focusing on strategies and tools that support practitioners to design local areas where human and natural pressures interfere. A prominent framework is provided by ecological network studies, whose design regards the combination of a set of green areas or patches (nodes) interconnected through environmental corridors (edges). Ecological networks are key for biodiversity protection and enhancement, as they are able to counteract fragmentation, and to create or strengthen relations and exchanges among otherwise isolated elements. Biodiversity evolution, indeed, depends on the quantity and quality of spatial cohesion of natural areas. In this paper, we propose a methodological framework based on network modeling to the study and monitoring of ecological systems. We use network properties and centrality measures (degree, clustering coefficient, and betweenness centrality) and take into account the intensity of the dispersal capacity by introducing the corresponding weighted centrality measures. We simulate the dynamics of ecological networks by monitoring the residual dispersal capacity and the number of connected components from three perspectives: random attacks, deterministic attacks according to decreasing betweenness centrality and influence of the master plans. We demonstrate how spatial network analysis is useful to monitor the performance of ecological networks and to support decision-making, management, and planning. The proposed methodology is applied to the case study of the peri-urban and urban areas of the town of Nuoro (Italy). Patches (nodes) have been selected among the ecosystems with target vegetal species holm oak (Quercus ilex) and cultivated (or wild) olive (Olea europaea var. sativa, O. europaea var. sylverstis) while the connecting corridors (links) enable for seed dispersal.