Primi risultati per una nuova regionalizzazione fitogeografia del territorio italiano

Biogeographia vol. XXVIII - 2007 (Pubb/icato il 30 dicembre 2007) Biogeografia de/I’Appennino eentra/e e sertentrionale: trenfanni dopo Primi risultati per una nuova regionalizzazione fitogeografica del territorio italiano CARLO BLASI, GOFFREDO FILIBECK*, SABINA BURRASCANO, RICCARDO COPIZ**, ROMEO DI PIETRO°, STEFAN IA ERCOLE, EDDA LATTANZI, LEONARDO ROSATI, AGNESE TILIA Dzpartimento di Bio/agizz Vegerzzle, Uniuersitiz di Roma qLa Szzpienzzz’: pizzzzzzle Aldo Mom 5, 00185 Roma (Italy); e-mzzil: czzrlo.b/zzsi@zmiromzz1.it *Dipzzrtimmt0 DEC 05, Universitfz de/[zz Tzzscizz, largo Universifiz, 01100 Viterbo {ftzz/y) **Dz'pzzrtz'mem‘0 S T A T, U7zz'z/ersiziz de[ M olise, contrzzdzz Fonte Lzzppone, 86190 P656‘/:76’, Isemizz (ltzzly) °Dz'pzzrtimem‘0 I TAC/‘1, Uiziuersitfz di Roma “La Szzpienzzz”, z/itz Flzzmirzitz 7 8, 00196 Roma (ftzzey) Key words: biogeographical regions, local fioras, potential natural vegetation, phytogeography, regionalization SUMMARY Biogeographical regionalization should not be confused with ecological cartography or landscape classification, as biogeographical classification should be based only on species distribution. Therefore, the optimal data set for a phytogeographical (fioristic) Classification of Italy would be a floristic atlas including all the vascular plants species of the country: grid cells should be treated as OGUS (Operational Geographic Unit) and elaborated through multivariate presence/ absence analysis. However, such an atlas has never been realized in our country. Aim of the paper is to present a quantitative phytogeographical classification of Italy based on available data, i.e. the new chet:l(—list of the Italian vascular Hora, the large amount ofpublished local Horas and information about the distribution of Potential Natural Vegetation (vegetation series). As the check-list shows the plant list of each of the 20 administrative regions of Italy, these can be treated as OGUS For a first, coarse—grain framework classification of the country. A more detailed and fine—grainecl analysis of Italy’s phytogeographical units can be made analyzing a wide set oflocal floras, chosen — among the many available — on the basis of their study area surface and ecological heterogeneity. We also present a detailed analysis regarding the chorological attributes of species exclusive of the Thyrrenic regions compared to the Adriatic ones. The complex of the analysis confirm the presence of a gradient north—south and a clear separation est—west along the Peninsula. Results confirm that the adopted method is a valuable approach and propose a new boundary for the Centre— European Region in Southern Italy. q INTRODUZIONE La distribuzione degli organismi dipende da fattori ecologici, cioe dalle catat- tetistiche dell’arnbiente e dalle interazioni fra organismi e comunita, e da fat