Heath species and heathlands of Italy: an analysis of their relationships under the perspective of climate change based on the description of habitats used for the project \u201cCarta della Natura\u201d (Italian Map of Nature).

The project \u201cItalian Map of Nature\u201d (IMN) is dedicated to create an electronic map (GIS) of the environmental state (quality and vulnerability) of the Italian territory at different scales. Up to now the GIS of IMN is offering maps at a scale 1:50,000. The environmental quality is estimated on the basis of biological description of habitats that can be mapped at this scale, the vulner- ability on the basis of variables related to the anthropogenic pressure. In this paper I want to show that the information collected for creating the data base of habitats for mapping purposes may be useful for getting information related to the climatic niche width of the species considered habitat indicators. In this paper I consider the heath species characterizing the IMN habitats of Italy in order to get an indirect estimation of the climatic vulnerability of Italian heathlands. To measure the climatic niche width of the species I propose a formula that combines the number of habitats (they characterize) with the heterogeneity of the habitats according to their distribution in altitudinal belts and in biogeographic regions. The results offer parameters on which to base a discussion for policy conservation of heaths and heathlands in Italy under the perspective of climate change