Assessment of ecotone changes over the last six decades in two cultural landscapes: The case of the Prosecco Hills of Conegliano and Valdobbiadene UNESCO site and of the Olive Groves of the Slopes between Assisi and Spoleto GIAHS site

Abstract Cultural landscapes are often characterized by a complex landscape structure providing different habitats, nesting place, food reservoirs and ecological networks, for different fauna and flora species. Edges between different land uses can be assimilated to ecotones, and land uses changes over the years also affect ecotones characteristics and associated biodiversity. This study intends to contribute to the understanding of the relation between land use changes and ecotone characteristics and changes in two Italian cultural landscapes inscribed in the UNESCO WHL and in the FAO GIAHS (Globally Important Agricultural Heritage Systems) Programme, applying a GIS-based methodology. In the last six decades, in both study sites, agricultural areas decreased with consequent increase of forests and shrublands. This trend affected ecotones presence and density, but in different ways depending on the characteristics of the study areas. In the Prosecco Hills of Conegliano and Valdobbiadene UNESCO site the analyses recorded an overall reduction of ecotones total length (− 6.4%), in particular of the first level ecotones (the ones between forests and agricultural areas) due to the loss of high altitude pastures that have been recolonized by forests, and of the second level ecotones (the ones between different types of cultivated areas) due to the agricultural mosaic simplification caused by the reduction of mixed cultivations and the spread of monocultures. In the Olive Groves of the Slopes between Assisi and Spoleto GIAHS site, similar land use trends caused an increase of the total length of first (+ 53.7%) and second level ecotones (+ 13.5%). This different behavior highlighted for the two sites, demonstrates that the relation between land use changes and ecotones changes is site-specific. The average density of first level ecotones decreased in both the study sites (− 20.2% in the UNESCO site and − 30.3% in the GIAHS site), while the maximum density remains high (424 m/ha in the UNESCO site and 794 m/ha in the GIAHS site). The applied methodology and the classification of ecotones according to a hierarchical system demonstrated to be effective in their identification and assessment. The study demonstrated that cultural landscapes are characterized by important ecotones networks and that preserving landscapes of recognized cultural value also means protecting ecotones, and associated habitats and biodiversity. Instead of only focusing on increasing protected areas number and surface, EU Biodiversity Strategy for 2030 should consider traditional cultural landscapes as a pillar for biodiversity conservation.