Mediterranean Basin

Potential distribution over the Mediterranean Basin of the olive tree—one of the best biological indicators of the Mediterranean Region (Oteros, 2014)[1]
Political Map of the Mediterranean Basin

In biogeography, the Mediterranean Basin /ˌmɛdɪtəˈreɪniən/ (also known as the Mediterranean region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have a Mediterranean climate, with mild, rainy winters and hot, dry summers, which supports characteristic Mediterranean forests, woodlands, and scrub vegetation.

As a rule of thumb, the Mediterranean Basin is the Old World region where olive trees grow.[2] However olive trees grow in other corners of the world which have a Mediterranean climate, and there are many areas around the Mediterranean Sea which do not have a Mediterranean climate and where olive trees cannot grow.

Geography

The Mediterranean basin covers portions of three continents Africa, Asia, and Europe.

It has a varied and contrasting topography. The Mediterranean Region offers an ever changing landscape of high mountains, rocky shores, impenetrable scrub, semi-arid steppes, coastal wetlands, sandy beaches and a myriad islands of various shapes and sizes dotted amidst the clear blue sea. Contrary to the classic sandy beach images portrayed in most tourist brochures, the Mediterranean is surprisingly hilly. Mountains can be seen from almost anywhere.[3]

The Mediterranean Basin extends into Western Asia, covering the western and southern portions of the peninsula of Turkey, excluding the temperate-climate mountains of central Turkey. It includes the Mediterranean climate Levant at the eastern end of the Mediterranean, bounded on the east and south by the Syrian and Negev deserts.

The northern portion of the Maghreb region of northwestern Africa has a Mediterranean climate, separated from the Sahara Desert, which extends across North Africa, by the Atlas Mountains. In the eastern Mediterranean the Sahara extends to the southern shore of the Mediterranean, with the exception of the northern fringe of the peninsula of Cyrenaica in Libya, which has a dry Mediterranean climate.

Europe lies to the north, and three large Southern European peninsulas, the Iberian Peninsula, Italian Peninsula, and the Balkan Peninsula, extend into the Mediterranean-climate zone. A system of folded mountains, including the Pyrenees dividing Spain from France, the Alps dividing Italy from Central Europe, the Dinaric Alps along the eastern Adriatic, and the Balkan and Rhodope mountains of the Balkan Peninsula divide the Mediterranean from the temperate climate regions of Western and Central Europe.

Köppen-Geiger-based map of the areas surrounding the Mediterranean Sea. Based on the work of M. C. Peel, B.L. Finlayson and T.A. McMahon at the University of Melbourne. For explanation of the colors see the image file "World_Koppen_Map.png" at Wikimedia Commons.

Geology and paleoclimatology

The Mediterranean Basin was shaped by the ancient collision of the northward-moving African-Arabian continent with the stable Eurasian continent. As Africa-Arabia moved north, it closed the former Tethys Sea, which formerly separated Eurasia from the ancient super continent of Gondwana, of which Africa was part. At about the same time, 170 mya in the Jurassic period, a small Neotethys ocean basin formed shortly before the Tethys Sea was closed at the eastern end. The collision pushed up a vast system of mountains, extending from the Pyrenees in Spain to the Zagros Mountains in Iran. This episode of mountain building, known as the Alpine orogeny, occurred mostly during the Oligocene (34 to 23 million years ago (mya)) and Miocene (23 to 5.3 mya) epochs. The Neotethys became larger during these collisions and associated folding and subduction.

About 6 mya during the late Miocene, the Mediterranean was closed at its western end by drifting Africa, which caused the entire sea to evaporate. There followed several (debated) episodes of sea drawdown and re-flooding known as the Messinian Salinity Crisis, which ended when the Atlantic last re-flooded the basin at the end of the Miocene.[4] Recent research has suggested that a desiccation-flooding cycle may have repeated several times [5][6] during the last 630,000 years of the Miocene epoch, which could explain several events of large amounts of salt deposition. Recent studies, however, show that repeated desiccation and re-flooding is unlikely from a geodynamic point of view. [7][8]

The end of the Miocene also marked a change in the Mediterranean Basin's climate. Fossil evidence shows that the Mediterranean Basin had a relatively humid subtropical climate with summer rainfall during the Miocene, which supported laurel forests. The shift to a Mediterranean climate occurred within the last 3.2–2.8 million years, during the Pliocene epoch, as summer rainfall decreased. The subtropical laurel forests retreated, although they persisted on the islands of Macaronesia off the Atlantic coast of Iberia and North Africa, and the present Mediterranean vegetation evolved, dominated by coniferous trees and sclerophyllous trees and shrubs, with small, hard, waxy leaves that prevent moisture loss in the dry summers. Much of these forests and shrublands have been altered beyond recognition by thousands of years of human habitation. There are now very few relatively intact natural areas in what was once a heavily wooded region.

Flora and fauna

Phytogeographically, the Mediterranean basin together with the nearby Atlantic coast, the Mediterranean woodlands and forests and Mediterranean dry woodlands and steppe of North Africa, the Black Sea coast of northeastern Anatolia, the southern coast of Crimea between Sevastopol and Feodosiya and the Black Sea coast between Anapa and Tuapse in Russia forms the Mediterranean Floristic Region, which belongs to the Tethyan Subkingdom of the Boreal Kingdom and is enclosed between the Circumboreal, Irano-Turanian, Saharo-Arabian and Macaronesian floristic regions.

The Mediterranean Region was first proposed by German botanist August Grisebach in the late 19th century.

Drosophyllaceae, recently segregated from Droseraceae, is the only plant family endemic to the region. Among the endemic plant genera are:

The genera Aubrieta, Sesamoides, Cynara, Dracunculus, Arisarum and Biarum are nearly endemic. Among the endemic species prominent in the Mediterranean vegetation are the Aleppo pine, stone pine, Mediterranean cypress, bay laurel, Oriental sweetgum, holm oak, kermes oak, strawberry tree, Greek strawberry tree, mastic, terebinth, common myrtle, oleander, Acanthus mollis and Vitex agnus-castus. Moreover, many plant taxa are shared with one of the four neighboring floristic regions only. According to different versions of Armen Takhtajan's delineation, the Mediterranean Region is further subdivided into seven to nine floristic provinces: Southwestern Mediterranean (or Southern Moroccan and Southwestern Mediterranean), Ibero-Balearian (or Iberian and Balearian), Liguro-Tyrrhenian, Adriatic, East Mediterranean, South Mediterranean and Crimeo-Novorossiysk.[9]

The Mediterranean Basin is the largest of the world's five Mediterranean forests, woodlands, and scrub regions. It is home to a number of plant communities, which vary with rainfall, elevation, latitude, and soils.

The Mediterranean Basin is home to considerable biodiversity, including 22,500 endemic vascular plant species. Conservation International designates the region as a biodiversity hotspot, because of its rich biodiversity and its threatened status. The Mediterranean Basin has an area of 2,085,292 km2, of which only 98,009 km2 remains undisturbed.

Endangered mammals of the Mediterranean Basin include the Mediterranean monk seal, the Barbary macaque, and the Iberian lynx.

Ecoregions

History

Neanderthals inhabited western Asia and the non-glaciated portions of Europe starting about 230,000 years ago. Modern humans moved into western Asia from Africa less than 100,000 years ago. Modern humans, known as Cro-Magnons, moved into Europe approximately 50-40,000 years ago.

The most recent glacial period, the Wisconsin glaciation, reached its maximum extent approximately 21,000 years ago, and ended approximately 12,000 years ago. A warm period, known as the Holocene climatic optimum, followed the ice age.

Food crops, including wheat, chickpeas, and olives, along with sheep and goats, were domesticated in the eastern Mediterranean in the 9th millennium BCE, which allowed for the establishment of agricultural settlements. Near Eastern crops spread to southeastern Europe in the 7th millennium BCE. Poppy and oats were domesticated in Europe from the 6th to the 3rd millennium BCE. Agricultural settlements spread around the Mediterranean Basin. Megaliths were constructed in Europe from 4500 – 1500 BCE.

A strengthening of the summer monsoon 9000–7000 years ago increased rainfall across the Sahara, which became a grassland, with lakes, rivers, and wetlands. After a period of climatic instability, the Sahara settled into a desert state by the 4th millennium BCE.

Agriculture

Wheat is the dominant grain grown around the Mediterranean Basin. Pulses and vegetables are also grown. The characteristic tree crop is the olive. Figs are another important fruit tree, and citrus, especially lemons, are grown where irrigation is present. Grapes are an important vine crop, grown for fruit and to make wine. Rice and summer vegetables are grown in irrigated areas.

See also

References

  1. ↑ Oteros Jose (2014) Modelización del ciclo fenológico reproductor del olivo (Tesis Doctoral). Universidad de Córdoba, Córdoba, España Link
  2. ↑ Ad Hoc Urban Sprawl in the Mediterranean City: Dispersing a Compact Tradition?, p. 61, at Google Books
  3. ↑ "Natura 2000 in the Mediterranean Region" (PDF). European Commission of the European Union. Retrieved August 6, 2015.
  4. ↑ W. Krijgsman; A. R. Fortuinb; F. J. Hilgenc; F. J. Sierrod (2001). "Astrochronology for the Messinian Sorbas basin (SE Spain) and orbital (precessional) forcing for evaporite cyclicity". Sedimentary Geology. 140: 43–60. Bibcode:2001SedG..140...43K. doi:10.1016/S0037-0738(00)00171-8.
  5. ↑ Gargani J., Rigollet C. (2007). "Mediterranean Sea level variations during the Messinian Salinity Crisis.". Geophysical Research Letters. 34 (L10405): L10405. Bibcode:2007GeoRL..3410405G. doi:10.1029/2007GL029885.
  6. ↑ Gargani J.; Moretti I.; Letouzey J. (2008). "Evaporite accumulation during the Messinian Salinity Crisis : The Suez Rift Case.". Geophysical Research Letters. 35 (2): L02401. Bibcode:2008GeoRL..35.2401G. doi:10.1029/2007gl032494.
  7. ↑ Govers, R. (2009). Choking the Mediterranean to dehydration: The Messinian salinity crisis Geology, 37 (2), 167-170 doi:10.1130/G25141A.1 Link
  8. ↑ Garcia-Castellanos, D., A. Villaseñor, 2011. Messinian salinity crisis regulated by competing tectonics and erosion at the Gibraltar Arc. Nature, 2011-12-15 pdf here Link
  9. ↑ Тахтаджян А. Л., Флористические деления суши и океана. Древнесредиземноморское подцарство.

Further reading

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