The European environmental policy strategies require that biodiversity protection should no longer be confined only to protected areas but promoted by connecting these areas through ecological networks. The European Directives 92/43/EEC and 79/409/EEC form the basis of the Natura 2000 network that is the major initiative for biodiversity conservation in the European Community: it is made up of 24,831 well-categorized sites that cover 17% of the territory of the Member States. Unfortunately, these Directives does not include provision for an ecological network in the sense of spatially or functionally connected territories or sites. This can be achieved by the implementation of the concepts expressed by the Pan-European Ecological Network (PEEN), an implementation tool of the Pan-European Biological and Landscape Diversity Strategy. For the establishment of the PEEN a schematization is conventionally adopted that identifies the following structural and functional units of the network: the core areas (focal nodes where most of the protected natural features are), the buffer zones (adjacent to the core areas and with a protective function for the core areas, through mitigation of the impact of the surrounding anthropogenic matrix) and the ecological corridors (various landscape structures that vary in size and shape, whose function is to promote the dynamics of dispersion of species between the natural areas). In our paper published in Biodiversity and Conservation (2012) we try to produce a methodological model that allow the Natura 2000 network to be integrated with the PEEN. This methodology must be based on phytosociological analyses, as these analyses led to the definition of the habitats of Directive 92/43/EEC and determined the choice of the Natura 2000 sites. At the landscape level the methodology must be integrated with geosynphytosociological analyses and with analyses used in the spatial schematization of the PEEN and currently in use in landscape ecology.
The central nodes of the ecological network (core areas and buffer zones) are defined on the basis of the areas where there is a higher density of the habitats of Directive 92/43/EEC (Figure 1). These areas are identified using the kernel method, which estimates the density distribution across the territory obtaining a cumulative density surface in all of the points in space.
The ecological corridors are identified according to the distribution of the plant communities and of the spread elements of the agricultural landscape (Figure 2). Rows of trees, hedgerows, woodlands, shrublands and grasslands, attributed to different phytosociological associations but spatially adjacent to each other, are considered as single polygons that comprise multiple types of vegetation. Then, these polygons are classified according to their relative sizes, and therefore to their degree of internal spatial connection.
|Figure 2. Ecological corridors in the province of Ancona (central Italy) (modified from Biondi et al. 2012)|
To make the model of this ecological network truly effective, it must overcome the unique structural and spatial vision upon which many of the planning and design proposals have been based. The understanding and management of the natural dynamics that can determine the constitution of the ecosystems must be considered in great detail. Moreover, to make the ecological network actually applicable in terms of the planning it is best not to limit the focus to individual species or species groups, as the integration of different species-specific networks is extremely complex and difficult to apply, and would arise from a non-univocal interpretation of the landscape. It is necessary to evaluate the structure and ecological function of the spatial mosaic as a whole. The goal is thus to make the whole territory suitable for the presence and displacement of the greatest number of species that can find sufficiently large and continuous suitable habitats in the central nodes of the network. The presence of a spread ‘naturalness’ in the territory is an essential requirement to maintain the general connectivity of the landscape elements.
Edoardo Biondi, Simona Casavecchia, Simone, Pesaresi and Liliana Zivkovic, 2012. Natura 2000 and the Pan-European Ecological Network:a new methodology for data integration. Biodiversity and Conservation 21(7):1741–1754.
Edoardo Biondi - Department of Agriculture, Food and Environmental Sciences, Marche Polytechnic University, via Brecce Bianche, 60131 Ancona, Italy.
Simona Casavecchia - Department of Agriculture, Food and Environmental Sciences, Marche Polytechnic University, via Brecce Bianche, 60131 Ancona, Italy.
Simone Pesaresi - Department of Agriculture, Food and Environmental Sciences, Marche Polytechnic University, via Brecce Bianche, 60131 Ancona, Italy.
Liliana Zivkovic - Department of Agriculture, Food and Environmental Sciences, Marche Polytechnic University, via Brecce Bianche, 60131 Ancona, Italy. email: email@example.com