Protected Areas — Habitats

The ArcGIS 9.3. software was used for the creation of habitat maps. The different types of habitats have been identified through the interpretation of aerial photos of the affected areas in a 1:2,500 video scale with insights also on a scale of 1:1,000. The use of such precise scales has allowed, thanks also to the excellent quality of the images, to define in greater detail not only the physiognomic aspects (for example precise delimitation between areas of gravel and cliff areas) but also aspects concerning the type of habitats (for example, it was possible to recognise in many cases the different types of subalpine and alpine lands). The map base used is that of the Regional Technical Charter (CTR2003) on a scale of 1:10.000. In order to assign any correspondence between the different types found with the habitats defined by Directive 92/43 (N2000), the following documents were used as a reference: Corine Biotopes manual — Habitats of the European Community (1991), key to reading Corine Biotopes; · Italian Habitats Interpretation Manual of Directive 92/43/EEC, available online at http://unipg.it/habitat/; Manuel d’interprétation des habitats de l’Union Européenne (1996), key to reading the habitats included in Annex I to Directive 92/43/EEC; · Guide des milieux naturels de Suisse (Delarze R. & Gonseth Y., 2008), also useful for the definition and recognition of the habitats of the Alpine territories bordering Switzerland; Habitats according to the EUNIS nomenclature: classification manual for Italian reality (APAT — Reports 39/2004). It should be noted that the attribution of N2000 correspondence was made mainly on the basis of the acquired knowledge concerning the “belonging” of the different types of habitats present in the Valle d’Aosta region to specific phytosociological alliances (and therefore to precise N2000 habitats) and not on actual vegetation surveys carried out in the field, this methodology does not apply to the creation of habitat maps on large areas, but only for vegetation maps on very small extensions. It should also be remembered that attributing a certain portion of the territory to a specific habitat never excludes the presence of other habitats either because it is possible to overlap them (for example in a forest it is possible to have a shrub and a herbaceous layer not distinguishable from aerial photos), and because, often, if not always, the different habitats appear in mosaic.