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The flowers of Crete, Greece.

Crete, the fifth largest island in the Mediterranean, is located equidistant from Europe, Asia and Africa. Its most outstanding features are its lengthy coastline, high mountains, fertile plains, extensive hilly areas, and stupendous gorges. The about 1000 km of coastline include both sandy beaches and high cliffs, with more and less pronounced peninsulas on the northern shore and many small islands; the northern coastlines are generally more accessible, while those to the south are often characterized by steep cliffs.

The most important mountains are Mount Ida, Crete's highest, which rises in the center of the island with its peak, Psiloritis, at 2456 meters, Lefka ori (White Mountains), rising to 2452 meters in the western portion of the island; and Mount Dikti, 2148 meters high and located to the east. In the easternmost part of the island is the Sitia range, which rises to 1476 meters. Other highlands, although not as prominent, cover a large portion of the territory of Crete and within them are found broad highland and fertile plains areas like Omalos, Messara, Nida and Lassithi.

The substrate of the island is 85% calcareous rock, and due to the frequency of karst phenomena there are many grottoes and gorges.The gorges are one of the most spectacular natural features of Crete: they are generally north-south rifts in the mountains that cross most of the island's width, with tall, steep, almost parallel walls at the base of which run watercourses that generally dry up in the summer. It is in the gorges and the highest areas of the mountainous areas that we find the majority of the plants endemic to Crete.

The watercourses are few, and those few there are are often dry from early summer onward. The wet areas include the Lake of Kournas, near Georgioupoli, and the man-made reservoir of Agia near Hania. Despite their quite limited extension, these environments are of great importance in that they provide a stopping-place between Africa and Europe for migrating birds. The climate is typically Mediterranean, with hot summers with only rare episodes of precipitation from May to October, and mild winters with greatest rainfall in December and January. Average annual rainfall on the northern coast is 700 mm, while on the much more arid southern coast it averages only 200-300 mm.

Local climatic conditions are strongly influenced by the nearness of the high mountains to the coast; in summer, haze may form on the north-facing slopes, which are damper than the areas with southern exposure. Snow persists on the highest peaks until summer; the spectacle offered by typically Mediterranean flowers blooming in the summer against snowcapped pinnacles is particularly evocative. The prevailing winds are the west wind from the Atlantic, the hot, dry Saharan sirocco, and the meltemi/ winds from central Asia that blow at sometimes annoying strength on the northern coast to mitigate temperatures that would otherwise be extreme.

During the Miocene era (26-25 million years ago), when the climate was warmer than it is today, there emerged in the area now occupied by the Aegean Sea a vast territory of which today's Crete is but a fragment. In the mid Miocene (18 million years ago), Crete was part of an unbroken strip of land linking continental Greece, the Aegean islands, and Turkey.

During the late Miocene, the Mediterranean Sea dried up a number of times. Toward the end of the Tertiary period (10 million years ago), the dry land underwent a number of changes due to sudden lowering or more prolonged geological phenomena: the sea invaded the land and the land-mass broke up. Thus, for example, eight million years ago what is now Crete was instead a group of several islands: today's highest mountain peaks. In the Pliocene era (3 million years ago), the landmass alternately lifted and sank, causing tectonic fractures; Crete was still a group of islands during this period.

Finally, during the Pleistocene (about 1 million years ago), the island took on its present form. Geological events have played a fundamental role in the evolution of the flora and fauna of the island: since the Mediterranean Sea has dried up repeatedly over the course of geological history, Crete has more than once been in communication with southern Greece, southwestern Turkey, and with such islands as Kythera, Antikythera, Rhodes, and the Cyclades, and this fact favored the migration of the plants from one part to another of whatever was the dry landmass at any given time. The repeated glaciations that alternated with interglacial periods through the Pleistocene were a/so very important in determining plant distribution: the formation of ice, with the consequent lowering of the level of the sea (it has been calculated that during the first glacial periods - Gunz, Mindel, and Riss the level of the sea was lower than it is today by hundreds of meters), created bridges linking widely-scattered territories and so facilitated the migration of plants and animals.

the flowers of Crete

There were also periods in geological history, other than our own, during which Crete was completely isolated and many existing species differentiated to produce new subspecies or even new species. That these geomorphological processes actually took place is confirmed by the presence, on Crete, of many elements native to the Balkan region and to Asia, as for example Ebenus cretica and Ricotia cretica, endemic species belonging to genera the distribution center of which is in Asia.

Most of the endemics are ancient species that were once widely distributed over the island and which, isolated by the various inundations of the Mediterranean, succeeded in surviving while their congeners disappeared: emblematic in this sense is the case of Petromarula pinnata, a monospecific genus endemic to Crete. It has been calculated that the isolation of the island lasted about five and one half million years', despite the length of this geological period, only a few species evolved in loco, probably due both to a shortage of new habitats that the new species could colonize and to strong competition among the existing species. Only when the ice withdrew did vast territories open to conquest by the plains species most ready to invade them.

Article by Marina Clauser , Photos by Andrea Innocenti and Stelios Asmargianakis



Posted on: 24/01/2011






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