Vascular flora evolution in the major Mediterranean islands

Vascular flora evolution in the major Mediterranean islands341The Sardinian flora is better represented in Corsica,where 84% of its flora occurs (Bocchieri et al.,2006); strong similarities with the Balearic Islands,as well as with coastal Spain and France (Fig. 3) arealso clear. This pattern is expected because the islandshave a similar geological history and they,particularly Sardinia, were closer to the Balearic Islandsand the Pyrenees in the Miocene, e.g. Soleiroliasoleirolii (Req.) Dandy, Urticaceae.Corsica shows the strongest floristic affinitywith Sardinia, when we compared endemics sharedbetween W Mediterranean islands. A particularlyconspicuous affinity also exists with the adjacentmainland of France (incl. Massif Central), NESpain and W Italy (e.g. Bupleurum stellatum L.Apiaceae). Crete shows the strongest floristic affinitywith Greece (e.g. Potentilla speciosa Willd.Rosaceae) but few similarities with Anatolia and EMediterranean.Cyprus shows the strongest floristic affinity withAnatolia (e.g. Onosma mite Boiss. et Heldr., Boraginaceae)and few similarities with East Mediterraneanand North African territories.HUMAN IMPACTIn the last centuries man has become the mostimportant vector for newcomers surpassing theother animals, birds, drift and wind; in this way formerisolation barriers were broken (Domina &Mazzola, 2011). By the trade of goods, plants andanimals Man has, accidentally or purposely, introducedlarge quantities of alien propagules into suitablycleared, new manmade habitats, or at leastinto a degraded, unbalanced environment. Thiscould have eliminated vulnerable old relic species.But if these losses did happen, it must have beenlong before reliable botanical records were made(Greuter, 2001). Looking at the damage that alreadyoccurred in a flora can be assessed its vulnerability.Rather than by new species introductionmost damages to floras are to be imputed to habitatloss; recent examples are the endemics Lysimachiaminoricensis J.J.Rodr. (Primulaceae) extinct fromMenorca and Adenostyles nebrodensis (Wagenitzet I. Müll.) Greuter (Asteraceae) practically extinctfrom Sicily.Vulnerability of a flora is evidenced by its openingto aliens. New introductions of plant diasporesis difficult in the Mediterranean because of nichepre-emption of a resident flora that has long beenwell adapted to existing habitat conditions (Runemark,1969). This is overcome when habitats havebeen pre-cleaned by human activities. So since ancienttimes the Mediterranean islands have been affectedby more intense human pressure, thereforethey host higher percentage of alien than the mainland.The most important relations in large islandshave been observed between aliens occurrence andfloristic density. In fact the aliens occurrence ineach island is related to extension and variety of habitatsactually susceptible to invasions (Domina &Mazzola, 2011).WHERE ARE WE GOINGLarge Mediterranean islands conserve mid-Tertiary floras rich in endemics. These plants arewell fitted to their natural environment and severalof them, in spite of their rarity, continue to surviveif their habitats are not manipulated.Touristic and urban development are seriously damagingunique biota and their plants. Research onMediterranean plant diversity, biology, demographyand distribution is to be intensified to betterknow how we can protect plant admitting a wisehuman development aware of natural resources.Awareness of conservation problems is arisingthroughout the Mediterranean, and if coordinatedefforts are done, we are still in time to preventheavy losses and to leave this rich and valuableplant heritage to future generations.ACKNOWLEDGEMENTSFunding by Università degli Studi di Palermo(ex 60 %) is gratefully acknowledged.REFERENCESBocchieri E., Mannini D. & Iiriti G., 2006. Endemic floraof Codula di Luna (Gulf of Orosei, Central EasternSardinia). Bocconea, 19: 233-242.Danin A., Baker I. & Baker H.G., 1978. Cytogeographyand taxonomy of the Portulaca oleracea L. polyploidcomplex. Israel Journal of Botany, 27: 177 211.