plant evolution in the mediterranean apr 2005

[...]... swing across north-west Europe Fourth, the majority of depressions originate within the Mediterranean Basin itself An important feature of rainfall in the Mediterranean is the marked regional variation in annual levels and timing of peak rainfall events Rainfall may be concentrated in the autumn, winter, or spring, depending on the region In the western Mediterranean, the peak rainfall occurs in the. .. ramifications for our understanding of the origins of the flora in the Mediterranean Basin and provides a fascinating setting for the study of plant evolution As Oleg Polunin (1980: 1) pointed out in the opening sentence of his book on the flora of the Balkans, The geological history of the Balkans is perhaps the most important single factor contributing to the diversity of the present-day flora’ I will... have since then become the determining factor in uencing Mediterranean forest cover, beginning in the east and moving west Around 10,000 bp, human-induced forest clearance was dotted around the landscape in the form of small, temporary clearings in an otherwise forested landscape (Pons and Thinon 1987) Since then, the impact of human activities has increased dramatically (Pons 1984) One can identify the. .. marked geographic variation in the dominant species present in these forests: evergreen oaks in drier areas of southern Spain, deciduous oaks in southern France and in Italy, firs in the northern Appenines, pines in the Maritime Alps and the eastern Pyrenees, and Pinus nigra subsp laricio forests on Corsica (Reille et al 1996) Pollen cores in southern Spain attest the presence of a Mediterranean- type vegetation... place the evolutionary processes which shape plant evolution into the context of the three main historical in uences on vegetation in the Mediterranean region, that is, geology, climate, and human activities I thus attempt to write a story of plant evolution in the context of regional history To write about the evolution of plants that inhabit the lands around the Mediterranean Sea requires the conception... occurs in the autumn A smaller peak occurs in spring around the coastal areas of the northern rim of the Mediterranean, in winter from the southern tip of Spain (Andalousia) across north Africa and Sicily to southern Italy (Calabria), and in spring in the centre of the Iberian peninsula, the Moroccan Atlas and the high plateau of Algeria Overall, rainfall declines from west to east More important, seasonal... (Nyssaceae) These extinctions were not simultaneous in different regions; Taxodiaceae, Symplocus, Nyssa, and a few others remained for longer periods in Catalonia than they did in the Languedoc The progressive appearance of the Mediterranean climatic regime, and in particular the precipitation regime was the key element in these extinctions While setting the scene for the evolution of one of the world’s... variation in the Mediterranean: (a) shrub–woodland interface in the Sierra de Cazorla in southern Spain (photo kindly supplied by C Herrera), (b) Pinus brutia forest pocket in the mountains of Crete, (c) oak woodland, limestone cliffs, scree slopes, and open garrigue vegetation adjacent to cultivated fields and abandoned cultivated areas in southern France 7 8 PLANT EVOLUTION IN THE MEDITERRANEAN understanding... Europe In the Mediterranean region, the decline set in during the Middle Pliocene whereas in the rest of Europe this decline did not occur till the Late Pliocene and Early Pleistocene (Michaux et al 1979) Indeed by the Middle Pliocene, taxa in the Hamamelidaceae and Juglandaceae diminished and the Taxodiaceae were completely lost from the coastal areas The loss of the Taxodiaceae and depletion of other... European plate 14 PLANT EVOLUTION IN THE MEDITERRANEAN Box 1.2 Geological history of the basins under the Mediterranean Sea islands are poised on these sills In the east, the Gibraltar sill maintains a degree of isolation from the Atlantic, with implications for sea currents and the climate of the Mediterranean region The Mediterranean Sea is subdivided into individual basins (black) separated by shallow . understanding of the origins of the flora in the Mediterranean Basin and provides a fascinating setting for the study of plant evolution. As Oleg Polunin (1980: 1) pointed out in the opening sentence. provide the frame- work for my discussion of plant evolution in the Mediterranean. My purpose is to firmly place the evolutionary processes which shape plant evolution into the context of the three. write about the evolution of plants that inhabit the lands around the Mediterranean Sea requires the conception of a certain unity which holds together the immense diversity present in the flora. This