Crucial points for a Habitat Red List in Italy

Sound assessment criteria, processes and thresholds are crucial tools for habitat conservation strategies and management decision making. Recently a number of scientists started to shift red-listing criteria, based on IUCN approach, from species to ecosystems. Unfortunately a remarkable heterogeneity still persists in the different approaches, mostly concerning the units to be assessed. In order to focus on a wide-scale accepted habitat classification, we concentrated on the Italian Habitats (H) included in 43/92/EEU Directive’s Annex I. The phytosociological basis of H’s descriptions, supported in Italy by the Italian Habitat Manual, offers a sharable interpretation tool and creates a useful link with the European and national biodiversity conservation strategies. Besides, the plant community concept adopted by Annex I agrees with EUNIS and Corine Biotopes, thus allowing future evaluations of all the habitats and not only those of Community interest. We performed some national scale assessments (H with restricted/localized, restricted/widespread, large/widespread distribution), emphasizing the weak points deriving from an unsuited use of EOO/AOO. Different H types show notable dissimilarities in spatial arrangement, due to H-specific structure and ecology, which deeply affect the identification of proper thresholds. New reading keys are suggested to evaluate the distribution decline, i.e. the H’s potential distribution, linked to the Natural Potential Vegetation concept, and the H’s successional stage, to provide specific attributes for threats evaluation. One of the weakest points remains the quantitative evaluation of H’s quality, bringing back to H definition. Almost each H type requires ad hoc criteria (vegetation cover/structure, averaged floristic composition and relative acceptable thresholds) and quality evaluation seems to be profitably performed only at a regional/local scale.