Mediterranean ecosystems facing global change, Portail de ressources électroniques en sciences humaines et sociales, Sub-chapter 2.4.4. Nevertheless, the time frame and evolutionary consequences of biogeographical events linked to repeated cycles of island connections and isolation, in relation to marine regressions-transgressions, remain largely unknown (Mansion et al., 2008). Economidou E. 1995L’appauvrissement de la flore et de la végétation des îles grecques, conséquence des activités humaines. (ed.) 2013Managing threatened plants in islands: task and priorities. After European colonization of these regions, fires were suppressed, which has caused some unintended consequences in these ecoregions; fuel builds up, so that when fires do come they are much more devastating, and some species dependent on fire for their reproduction are now threatened. The unique terraced landscapes have disappeared on most of these islands. Médail F. IN PRESSPlant biogeography and vegetation patterns of the Mediterranean islands. 0000010287 00000 n
2016). In Greece, the situation has been of particular concern for the last few decades given the increase in frequent intense wildfires. In: Gillespie R.G. Bulletin de la Société botanique de France, 121, 175-204. The smallest islands should not be neglected, as they are often isolated territories where micro-speciation processes occurs, offering modern refuge-areas for diversity that is put at risk by the impacts of human activity on the coasts of the adjacent mainland. Sub-chapter 2.4.3. It's characterized by drier warmer months and mild, wet colder months. This zone is determined chiefly by its climate, which is characterized by very dry summers and mild, rainy winters, but it has long been much differentiated by its inhabitants. The similarity of form andfunctional response of the vegetation to the rigorous mediterraneanenvironment is therefore a striking example of evolutionary convergence,and has resulted in a high degree of endemism within the regionalfloras." Blondel J. Omissions? Local persistence of Mediterranean plants, notably perennials, in diverse microhabitats may be due to multiple demographic strategies of persistence by longevity or regeneration, depending on the local or regional conditions (García & Zamora, 2003). Deciduous trees were widespread during the postglacial period, notably in the northern Mediterranean, but these forests were severely impacted by humans and their livestock. Israel Journal of Botany, 39, 481-508. T Letcher), Oxford, UK: Elsevier Press, pp. & Clague D.A. In this essay you will find out about how plants survive and multiply in a dry heat and the different types that exist. Rühl J.& Pasta S. 2008Plant succession on Sicilian terraces. 1995Changements socio-économiques et conservation de la flore dans les îles de la Méditerranée. ; THIÉBAULT, Stéphane (dir.). The European shrublands have also been shaped by anthropogenic fire, historically associated with transhumance herding of sheep and goats. 0000066920 00000 n
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8,000–7,000 cal. Global Change Biology, 8, 531-44. & Rešetnik I. 100 individuals occupy only one square meter. “Sub-chapter 2.4.3. A Mediterranean climate gets its name from the Mediterranean Basin, where this type of weather is most common. For example, the relation between successional processes and increased grazing pressure after land abandonment is still uncertain in many Mediterranean islands (e.g. On this fire-prone island, 28,000 starting fires occurred between 1973-2004 (i.e. 20Fire regime changes and the occurrence of extreme fire events (or “megafires”) are related to both land use change and climate change, and involve multiple biotic and socio-economic drivers (e.g. 8Today, there is a slight increase in permanent human population on the bigger islands, whereas the medium-sized islands – except some hot-spots of tourism such as Corfu and Djerba – are undergoing a population decline. 14Sea level rise (SLR) is another important component of climate change. Politi P.I., Georghiou K. & Arianoutsou M. 2011Reproductive biology of Abies cephalonica Loudon in Mount Aenos National Park, Cephalonia, Greece. 1The profound environmental heterogeneities and the complex historical biogeography explain the high diversity of landscapes and vegetation types in the Mediterranean Basin, one of the world’s biodiversity hot-spots (Médail & Myers, 2004). 2nd Botanical Conference in Menorca. 90 under Mediterranean climate, marked by a strong deficit of rainfall during the warm season, causing stress for 91 the vegetation submitted to a dry summer period (Gauquelin 2011). Distribution of Mediterranean Climate: The Warm Temperate Western Margin Climate is found in relatively few areas in the world. Forest cover, which was only 17.6% in 1866 (153,775 ha), is currently 58%, an increase of 3.3% over a period of 150 years (Panaïotis et al. Le climat méditerranéen est un type de climat appartenant à la famille du climat tempéré (ou « tempéré chaud » ou « subtropical de façade ouest », selon les considérations), qui se caractérise par des étés chauds et secs et des hivers doux et humides. Regional rates of sea level change may increase by a factor of 1 to 6 relative to the observed long term rates (Galassi & Spada, 2014). doi:10.1371/journal.pone.0006392. Médail F. 2008Ecosystems: Mediterranean. For the emblematic Corsican pine (Pinus nigra subsp. trailer
Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. 18Like grazing, forest fire has been a major driving force of Mediterranean ecosystem dynamics since the emergence of the Mediterranean climate, 3.2 Ma ago. In: Climate Change: Observed Impacts on Planet Earth, 2nd edn. Le Houérou H.N. All these ecoregions are highly distinctive, collectively harboring 10% of the Earth's plant species. Slim H., Trousset P., Paskoff R. & Oueslati A., 2004Le littoral de la Tunisie. Forty nine islands cover more than 100 km2, of which 36 cover more than 200 km2. The fynbos and Southwest Australia shrublands have flora that are significantly more diverse than the other ecoregions, although any Mediterranean shrubland is still rich in species and endemics relative to other non-forest ecoregions.. Peñuelas J., Filella I. They emphasize with abundance of migratory birds, migrate in summer to climates less hot and dry and others in winter. Furthermore, there often is spatial congruence between the most fire-affected micro-regions and the main cattle-rearing regions, like in Corsica. Plant biodiversity and vegetation on Mediterranean islands in the face of global change. 2012Dynamiques récentes des sebkas littorales de l’archipel des Kerkennah (Tunisie centro-méridionale): apport de la télédétection. Cerabolini B., Caccianiga M. & Andreis C. 1996Secondary successions due to agricultural dereliction and post-fire recovery in the Mediterranean vegetation: first outlines in the western Elba (North Tyrrhenian sea-Italy). Fires contributed to the frequent dominance of shrubland on islands during the mid-Holocene (ca. • Similar biomarker values between Mediterranean and north Atlantic (IODP SITE 608). Around the Table 1. Much of the woody vegetation in Mediterranean-climate regions is sclerophyll, which means 'hard-leaved' in Greek. 2014). 6Most changes in Mediterranean ecosystems are linked with human land use and its dynamics over time and these will likely continue to play a major role (Blondel & Médail, 2009).  The hot, dry summers make much of the region prone to fires, and lightning-caused fires occur with some frequency. Mansion G., Rosenbaum G., Schoenenberger N., Bacchetta G., Rosselló J.A. This is of particularly concern for efficient evolutionary conservation of these heterogeneous insular floras. Etienne L., Dahech S., Beltrando G. & Daoud A. Actes du symposium international, Kerkennah (Tunisie), 20-24 octobre 2015, Sfax: pp. & Roberts C. 2005Confronting a biome crisis: global disparities of habitat loss and protection. In the Ionian Sea, there are ca. However, most plants interact with bioclimatic characteristics at a physiological rather than macro-climatic level (Curtis et al. Geo-archaeological studies mention significant flooding of coastal lands and antique remains, up to two meters 2,000 years ago (Slim et al. Etna, 3,342 m a.s.l. (eds.) What Are The Features Of A Polar Climate? Landscape series, volume 9. 0000128256 00000 n
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Nature, 532, 99-102. CEMEX (Monterrey), Conservation International (Washington) & Agrupación Sierra Madre (Mexico), pp. Kadis K. & Georghiou K. 2010Seed dispersal and germination behavior of three threatened endemic labiates of Cyprus.