Plants

Biodiversity is high in Greece. The number of species of flowering plants alone is more than 6,000; this may be compared with 2,113 in the entire British Isles, which have an area well over twice as large as Greece.

Mediterranean ecosystems occur in zones with limits determined by a combination of such factors as latitude, elevation, exposure, and precipitation. The lowest zone extends from sea level to about 1,000 m elevation, and contains the typical vegetation of the Mediterranean climatic zone proper. Before human interference, this was in large part a belt of forests consisting mainly of pines and evergreen oaks, with thick shady galleries of broadleaved trees along watercourses.

Here also in dryer sections occurs the most distinctive plant association of the Mediterranean basin, the maquis, a brushy cover of hardy shrubs that varies from sparse to impenetrable. It is widespread in Greece and might be said to be the most typical cover of hillsides there. The bushes or small trees ofwhich it is composed rarely exceed 8 m in height. Some students of plant succession regard maquis as a degenerate association, and it often becomes established after forest has been removed, but it is not always a sign of disturbance. In many districts it is the climax, that is, a biotic community that perpetuates itself under locally prevailing conditions of soil and climate. The most prominent species are broad sclerophylls, which are evergreen trees with leaves adapted to drought by thick hairy, leathery, oily, or waxy coverings. Some maquis plants survive in dry conditions by having extensive root systems, high osmotic pressure, and the evergreen ability to utilize winter moisture. Most importantly, maquis is a community of plants that is perfectly adapted to periodic fires, which are widespread in Greece. Each species possesses one or more adaptations that enable it to reestablish itself after fire: by recuperating rapidly, sprouting from buried root crowns, or germinating from seeds that respond to heat or spread into a burned area on the winds or by other means and find bare or scorched soil a congenial place to germinate. Typical maquis plants are holm-oak and kermes oak, junipers, arbutus, laurel, myrtle, tree heather, rockrose, broom, rosemary, and the shrubby mastic tree (Pistacia lentis-cus), a widespread plant of the maquis that is cultivated on Chios.

After repeated destruction by clearing, browsing, or fire, or in harsh locations, maquis may be replaced by garigue or ‘‘rock heath,’’ a tough, low association of shrubs that are often spiny. It is rarely more than 50 cm high, often lower than the rocks among which it grows. Among more than two hundred common species that occur in it are many spice-bearing herbs such as basil, garlic, hyssop, lavender, oregano, rosemary, rue, sage, savory, and thyme. Their pleasant odors waft far out to sea, especially in spring, the flowering season.

Garigue may be tough, but where conditions are even more extreme or overexploited, not even it can survive, and there a winter grassland or ‘‘steppe’’ may occur. It includes annuals adapted to the moister half of the year, and perennials that grow from rootstocks, tubers, or bulbs. Like garigue, grassland blooms in spring before the desiccating winds of summer. Species that survive grazing do best here; typical are asphodel, mullein, sea squill, thistle, and members of the buttercup, composite, grass, legume, lily, mint, mustard, parsley, pink, and rockrose families.

The deciduous forest zone occurs, where rainfall permits, above the zone just described, and up to around 1,400 m, and is sometimes called the upper Mediterranean zone. Dominant trees are deciduous oaks, elm, beech, chestnut, ash, and hornbeam. In Greece these forests are seen in the northern mountains; elsewhere they may have been eliminated by human use over the centuries.

At even greater altitudes the mountain zone, or coniferous forest zone, extends upward to the tree line, which is found at about 2,400 m on Mount Olympos. In rare pristine conditions, a high forest of pines, silver fir, cedars, and junipers survives, interspersed with open meadows. One such forest in Greece, which has apparently remained untouched since time immemorial, has been discovered in the Rhodope Mountains north ofDrama near the Bulgarian frontier. Greece created a national park of 585 ha in 1975 to protect a portion of this unique forest of beech, fir, Norway spruce, and other trees, with its rich population of birds and mammals. Among the birds found there are the capercaillie, golden eagle, and black and griffon vultures, while the mammals include bear, wolf, lynx, red and roe deer, and chamois. The scenery is exquisite, with mountains, gorges, streams, and waterfalls. Precipitation is higher in this subalpine zone, taking the form of snow in the winter and thunderstorms in the summer. The growing season, limited by winter cold rather than dryness, takes place in the summer.

Above the tree line is an alpine tundra of dwarfed plants and lichens. Tiny flowering plants are adapted to a short summer growing season, during which they must bloom and set seed quickly before frosts return. On the bare rocks of the summits, snow may persist until the hottest part of the summer. Species in this zone are often narrowly endemic, occurring only on one mountain or range, a fact noted by the ancient botanist, Theophrastos (Historia Plantarum 3.18.1). Mount Olympos, for example, has a dozen or so species that grow only there among the 150 species that occur there above the tree line. Among the ‘‘locals’’ are a cerastium named after Theophrastos, an alyssum, a violet, and an Achillea.