Biodiversity Journal, 2012, 3 (4): 337-342 Vascular flora evolution in the major Mediterranean islands Gianniantonio Domina 1* , Pasquale Marino 2 , Vivienne Spadaro 2 & Francesco Maria Raimondo 2 1 Dipartimento di Scienze Agrarie e Forestali, Università degli Studi di Palermo, via Archirafi 38 - 90123 Palermo, Italy; e-mail: gianniantonio.domina@unipa.it 2 Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche, Università degli Studi di Palermo, via Archirafi 38 90123 Palermo, Italy * Corresponding author ABSTRACT Characteristics of Mediterranean island floras are analyzed with stress on endemic units. On these bases the main relationships between the major Mediterranean areas and the inland ter- ritories with the strongest floristic affinities are analyzed. Finally the role of aliens in Mediter- ranean island floras and threats are discussed. KEY WORDS Biogeography; Mediterranean; endemism; alien flora. Received 11.05.2012; accepted 20.11.2012; printed 30.12.2012 Proceedings of the 1 st International Congress “Insularity and Biodiversity”, May 11 th -13 th , 2012 - Palermo (Italy) INTRODUCTION The Mediterranean is among the richest regions in the world for wild and cultivated species. Cir- cum-Mediterranean countries house about 25,000 species, almost one tenth of the world's vascular flora, the 63% of which are endemic (Greuter, 1991; Medail & Quezel, 1999). A peculiarity of this area is the high amount of species with a narrow range, many of which are local endemics. In some sectors endemics are more than 20%. Among these there is Sicily and the other major Mediterranean islands and island groups: Baleares, Corse, Sardinia, Kriti, Cyprus with their mountain areas. The main reason for this high endemism can be searched in the pronounced habitat fragmentation that characterises the Mediterranean area as a whole. CHARACTERISTICS OF MEDITERRA- NEAN ISLAND FLORAS Mediterranean island flora is relatively well known although each year new species, sometimes completely unknown, are described (e.g. Ptiloste- mon greuteri Raimondo et Domina. Fig.1). Tradi- tionally the floras of large Mediterranean islands are considered ancient, relatively poor in species, rich in endemic taxa and particularly vulnerable (Greuter, 1995). Permanence in situ and prolonged evolutionary standstill are salient characteristics of Mediterra- nean island floras (Greuter, 1979). These have a re- lictual nature and are at least ancient as the islands themselves; for Cyprus, Crete and the Baleares about 5-6 milion years, dating back to the post-Mes- sinian transgression (Greuter, 1995). According to the equilibrium theory of island biogeography (MacArthur & Wilson, 1967) the number of species on an island is in a state of dynamic equilibrium; diversity eventually stabilizes but turnover remains high as species continuously colonize and go ex- tinct. The flora of the Mediterranean was subject to an impoverishment due to the climatic fluctuation during Pliocene and a subsequent enrichment due to immigration by long range dispersal (Quézel & Médail, 2003). This is more manifest in the islands where original species pool seems to become con-