Large-Scale Post-Glacial Distribution of Vegetation Structures in the Mediterranean Region. Quézel, P. In Mazzoleni, S., Pasquale, G. D., Mulligan, M., Martino, P. D., & Rego, F., editors, Recent Dynamics of the Mediterranean Vegetation and Landscape, pages 1–12. John Wiley & Sons, Ltd, Chichester, UK, April, 2004.
doi  abstract   bibtex   
[Excerpt: Conclusions] We have seen that the vegetation structures and the most important landscapes in the Mediterranean basin are currently the result of both climatic changes that took place over some 12 millennia and modern local ecological factors. Among the latter, geomorphology, temperature and precipitation have played a fundamental role in the organisation of the large-scale arboreal groupings, as well as in the shrublands and herbaceous grasslands, which often are their derivatives. But the last phase of climatic improvement corresponded with the explosion of those civilisations, especially from its mid-point onwards, which profoundly upset the natural equilibrium that had been established. [] The intensive increase in grazing and subsequently farming led to far-reaching changes, which had, as their most apparent consequence, a massive reduction of the forests, the cultivation of land and large-scale extension of grazing land. In the space of a few millennia, with the exception of some mountain zones that were partially spared, human action profoundly altered the ecological balance that had been achieved over 4 or 5 millennia, so that nowadays it is difficult, especially in low-lying belts and on deep soils, to form a precise idea about the original vegetation. The arboreal species, where they still exist, occupy only minimal areas compared to their potential initial cover. [] The primary forests, which are by definition plurispecific, have generally become scarcely varied or indeed monospecific. Their opening up, followed by the spread of burning practices, has favoured the extension of chamephytes, and also of scrublands or of perennial grasslands, which, by excessive use and soil erosion, have transformed into annual grasslands. A precarious equilibrium has come into being, linked to a more or less controlled traditional land use, in different periods such as the Roman Empire, the Middle Ages, and the eigh- teenth and nineteenth centuries in particular (Godron, 1989). This may have created a certain impression of stability (Kunholtz-Lordat, 1938), but the radical economic and social transformations that have taken place since the end of the last century have upset this balance once again. [] The northern countries that have been affected by industrial development and the marked abandonment of the land in zones of low productivity has favoured a biological recuperation featuring, above all, expansionist conifers such as P . halepensis and P . sylvestris in particular, which in spite of the spread of forest fires has led, for example, in Provence, to a doubling of the areas of natural population in less than a century (Barbero and Quezel, 1990), and the widespread renewal of the matorral through the reconstitution of the pre-forestal structures based above all on Quercus coccifera and the widespread closing of herbaceous scrublands. The human residential presence, locally important and very intense in coastal zones, is an additional cause of disturbance. This has led to a significant loss in biodiversity as a direct consequence, and it also leads to uniformity in the landscapes, which is not compatible with the generalised perception of the Mediterranean world. [] On the other hand, the countries to the south and east of the basin have a sizeable population growth combined with a still predominantly precarious way of life, which has led to an exacerbation of the use of natural resources: illegal tree felling, forest clearance, intensive grazing and misuse of the matorrals and steppes has led to the rapid destruction of the biological heritage (cf. above). Currently, for example, more than half of the north African forests have been destroyed or at least have been profoundly altered in the space of only a few decades, and steppes and matorrals are being transformed into grasslands with annuals with a very low yield, progressively invaded by thorny or toxic species. [] In each of these cases, and for the opposite reasons, the Mediterranean vegetation is currently undergoing drastic and rapid transformations, which are undoubtedly every bit as far-reaching as those that characterised the first half of the Holocene!
@incollection{quezelLargeScalePostGlacialDistribution2004,
  title = {Large-{{Scale Post}}-{{Glacial Distribution}} of {{Vegetation Structures}} in the {{Mediterranean Region}}},
  booktitle = {Recent {{Dynamics}} of the {{Mediterranean Vegetation}} and {{Landscape}}},
  author = {Qu{\'e}zel, Pierre},
  editor = {Mazzoleni, Stefano and Pasquale, Gaetano D. and Mulligan, Mark and Martino, Paolo D. and Rego, Francisco},
  year = {2004},
  month = apr,
  pages = {1--12},
  publisher = {{John Wiley \& Sons, Ltd}},
  address = {{Chichester, UK}},
  doi = {10.1002/0470093714.ch1},
  abstract = {[Excerpt: Conclusions] We have seen that the vegetation structures and the most important landscapes in the Mediterranean basin are currently the result of both climatic changes that took place over some 12 millennia and modern local ecological factors. Among the latter, geomorphology, temperature and precipitation have played a fundamental role in the organisation of the large-scale arboreal groupings, as well as in the shrublands and herbaceous grasslands, which often are their derivatives. But the last phase of climatic improvement corresponded with the explosion of those civilisations, especially from its mid-point onwards, which profoundly upset the natural equilibrium that had been established.

[] The intensive increase in grazing and subsequently farming led to far-reaching changes, which had, as their most apparent consequence, a massive reduction of the forests, the cultivation of land and large-scale extension of grazing land. In the space of a few millennia, with the exception of some mountain zones that were partially spared, human action profoundly altered the ecological balance that had been achieved over 4 or 5 millennia, so that nowadays it is difficult, especially in low-lying belts and on deep soils, to form a precise idea about the original vegetation. The arboreal species, where they still exist, occupy only minimal areas compared to their potential initial cover.

[] The primary forests, which are by definition plurispecific, have generally become scarcely varied or indeed monospecific. Their opening up, followed by the spread of burning practices, has favoured the extension of chamephytes, and also of scrublands or of perennial grasslands, which, by excessive use and soil erosion, have transformed into annual grasslands. A precarious equilibrium has come into being, linked to a more or less controlled traditional land use, in different periods such as the Roman Empire, the Middle Ages, and the eigh- teenth and nineteenth centuries in particular (Godron, 1989). This may have created a certain impression of stability (Kunholtz-Lordat, 1938), but the radical economic and social transformations that have taken place since the end of the last century have upset this balance once again.

[] The northern countries that have been affected by industrial development and the marked abandonment of the land in zones of low productivity has favoured a biological recuperation featuring, above all, expansionist conifers such as P . halepensis and P . sylvestris in particular, which in spite of the spread of forest fires has led, for example, in Provence, to a doubling of the areas of natural population in less than a century (Barbero and Quezel, 1990), and the widespread renewal of the matorral through the reconstitution of the pre-forestal structures based above all on Quercus coccifera and the widespread closing of herbaceous scrublands. The human residential presence, locally important and very intense in coastal zones, is an additional cause of disturbance. This has led to a significant loss in biodiversity as a direct consequence, and it also leads to uniformity in the landscapes, which is not compatible with the generalised perception of the Mediterranean world.

[] On the other hand, the countries to the south and east of the basin have a sizeable population growth combined with a still predominantly precarious way of life, which has led to an exacerbation of the use of natural resources: illegal tree felling, forest clearance, intensive grazing and misuse of the matorrals and steppes has led to the rapid destruction of the biological heritage (cf. above). Currently, for example, more than half of the north African forests have been destroyed or at least have been profoundly altered in the space of only a few decades, and steppes and matorrals are being transformed into grasslands with annuals with a very low yield, progressively invaded by thorny or toxic species.

[] In each of these cases, and for the opposite reasons, the Mediterranean vegetation is currently undergoing drastic and rapid transformations, which are undoubtedly every bit as far-reaching as those that characterised the first half of the Holocene!},
  isbn = {978-0-470-09371-9},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-13699742,~to-add-doi-URL,forest-resources,mediterranean-region,species-evolution,vegetation-types},
  lccn = {INRMM-MiD:c-13699742}
}
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