Mediterranean climate

The pattern

Mediterranean climates sit on the western coasts of continents between approximately 30° and 45° latitude (north or south), where the seasonal migration of the subtropical high-pressure systems produces dry summers (when the high sits overhead) and wet winters (when the high retreats poleward and lets mid-latitude storm tracks reach the coast). The combination of mild temperatures (rarely freezing, rarely above ~35°C), winter wetness, and summer drought selects for a very particular flora — sclerophyll (hard-leaved) evergreen shrubs and small trees that conserve water in summer and photosynthesize through the cool wet winter rather than dropping leaves like temperate deciduous forests.

The five regions

The Mediterranean-climate regions converge on similar vegetation structure despite no shared evolutionary history:

Region	Local name for the vegetation	Iconic genera
Mediterranean Basin	maquis, garrigue, macchia	Quercus ilex, Quercus suber, Olea, Cistus, Pistacia, Lavandula, Rosmarinus, Thymus
California	chaparral	Adenostoma, Arctostaphylos, Ceanothus, Quercus agrifolia, Salvia
Central Chile	matorral	Acacia caven, Lithraea, Quillaja, Cryptocarya
Cape Floristic Region	fynbos, renosterveld	Protea, Erica, Restio, Pelargonium, Leucadendron
Southwestern Australia	kwongan	Banksia, Hakea, Eucalyptus, Verticordia, Acacia

The five regions are evolutionary independent — Australia’s Banksia-and-Eucalyptus flora, the Cape’s Protea-and-Erica fynbos, and California’s Adenostoma chaparral share virtually no genera. Yet the leaves look similar, the shrub heights converge, the fire-adaptation patterns rhyme. The Mediterranean-climate signal is strong enough to produce convergent evolution at the biome scale.

What grows in Mediterranean climate

The world’s four great Old World fruit trees — [[olive|olive]], [[grape|grape]], [[fig|fig]], [[pomegranate|pomegranate]] — are all Mediterranean-climate species. Cork (Quercus suber), date palm, almond, pistachio, walnut, citrus (introduced from Asia but thriving), and many of the world’s wine, olive-oil, and stone-fruit industries are Mediterranean-climate enterprises. The same climate signal therefore underlies the agricultural economies of southern Europe, North Africa, central Chile, California’s coastal-valley belt, the South African Western Cape, and southwestern Australia. Five regions, one climate, similar economies.

Fire and biodiversity

Mediterranean-climate ecosystems are fire-adapted — periodic summer wildfires are part of the system, not an exception to it. Many of the iconic genera (Banksia, Pinus halepensis, several Protea, several Eucalyptus, several Adenostoma) have serotinous cones or fruits that only open after fire, or have lignotubers that resprout after the above-ground plant burns. Fire suppression in any of these regions reshapes the vegetation and damages the long-term biodiversity. Climate-change-intensified fire seasons in California, Australia, and the Mediterranean Basin in the 2010s and 2020s have begun to test whether the fire-adaptation envelope is being exceeded.

See also

Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.

• Demonstrated by: [[mediterranean-basin]] · [[cape-floristic-region]] · [[central-coast-california]]

Sources

• di Castri, Francesco, Goodall, David W., Specht, Raymond L. (eds.), Mediterranean-Type Shrublands (1981)
• Cowling, Richard et al., “Plant diversity in Mediterranean-climate regions” (TREE 1996)
• Wikipedia — Mediterranean climate

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A concept entry in the 0mn1.one wiki.