Mediterranean Basin

The Mediterranean Basin Hotspot covers some 2 085 292 km² and stretches from Portugal to Jordan and from Morocco to northern Italy. It encompasses over 90% of Greece, Lebanon, and Portugal, but less than 10% of France, Algeria, and Libya. In Spain, 6 000 of the country's 7 500 plant species occur within the Mediterranean climate zone; in Israel, 1 500 out of 2 200; and in Morocco, 3 800 out of 4 200 (Quézel 1985; Greuter 1991). The hotspot also includes the Canary Islands, Madeira, and the Selvages (Selvagens) Islands and, in contrast to the former definition of this hotspot (Myers and Cowling 1999), the region is here considered to also include the Azores and Cape Verde Islands, even though the floristic affinities of these two Macaronesian island groups lie more closely with Europe and Africa, respectively.

Of overwhelming importance in understanding the origins and diversity of the Mediterranean Basin biota is the region's location at the intersection of two major landmasses, Eurasia and Africa. Indeed, the collision between these two continental plates during the mid-Tertiary is responsible for the Basin's spectacular scenery. The Basin's violent geological history has produced an unusual geographical and topographical diversity, with high mountain ranges (more than 4 500 m in elevation), peninsulas, and one of the largest archipelagos in the world (the Mediterranean Sea includes several hundred islands and islets). The physiographic diversity of the region has resulted in a wide range of local climates, with mean annual rainfall ranging from 100 mm up to 3 000 mm (Blondel and Aronson 1999).

The typical and most widespread vegetation type is maquis or matorral, a hard-leaved shrubland dominated by Cistus, Erica, Genista, Juniperus, Myrtus, Phillyrea, Pistacia, and other evergreens, and similar in appearance to the chaparral of California and the matorral of Chile (Di Castri and Mooney 1973). Although maquis now covers more than half of the region, much of it has been derived from forest formations created by humaninduced disturbances. Frequent burning of maquis results in depauperate vegetation dominated by Kermes oak (Quercus coccifera), Cistus spp. or Sarcopoterium spinosum, all of which regenerate rapidly after fire by sprouting or mass germination.

Shrublands, including maquis and the aromatic, softleaved and drought phrygana of Rosmarinus, Salvia, and Thymus, persist in the semiarid, lowland, and coastal regions of the Basin. However, prior to the onset of significant human impact, which started some 8 000 years ago, most of the Mediterranean Basin was covered by some form of forests (Quézel and Médail 2003), including: evergreen oak forests (Quercus ilex, Q. suber, and Q. coccifera ssp. calliprinos); deciduous forests (Quercus canariensis, Q. faginea, Q. frainetto, Q. ithaburensis, Q. petraea, Q. pubescens, Q. pyrenaica, and Fagus sylvatica); and conifer forests (Abies spp., Cedrus spp., Juniperus spp., and Pinus spp.).

The flora of the Mediterranean Basin is comprised of around 25 000 species of vascular plants, 13 000 of which are endemic (Quézel 1985; Greuter 1991). These figures include taxonomically doubtful taxa (6% to 9%) and naturalized exotics (less than 3%). As we are considering here only confirmed native species, we subtract 10% for a figure of 22 500 (and 11 700 endemics). The plant species endemic to the Mediterranean Basin are not a random assemblage in terms of their taxonomic affinities, biology, habitat requirements, and geographical distribution. Rather, the flora comprises a complex admixture of Mediterranean woody plants belonging to pre-Mediterranean lineages (start of the Tertiary) (Verdú et al. 2003) and localized neoendemics composed predominantly of herbs and subshrubs in the families Asteraceae, Brassicaceae, Caryophyllaceae, Cistaceae, Fabaceae, Lamiaceae, Poaceae, Ranunculaceae, and so on. Endemics are mainly concentrated on some Tertiary and Pleistocene refugia on islands, peninsulas, rocky cliffs, and mountain peaks (Médail and Verlaque 1997). Nevertheless, endemism at the higher level is very reduced, with only two endemic families (Aphyllanthaceae and Drosophyllaceae), both represented by single species, Aphyllanthes monspeliensis and Drosophyllum lusitanicum. The Mediterranean Region also harbors a high degree of tree richness and endemism (290 indigenous tree species with 201 endemics) (Quézel and Médail 2003). A number of trees are important flagships, including the cedars (such as the famous cedar of Lebanon, Cedrus libani); the argan tree (Argania spinosa), a species in the Souss region of southwest Morocco; oriental sweet gum (Liquidambar orientalis); and Cretan date palm (Phoenix theophrasti) in Greece and western Turkey.

The principal foci in the Mediterranean are 10 regional mini-hotspots within the larger hotspot, characterized by areas of high plant richness and narrow endemism of more than 10% (Médail and Quézel 1997, 1999): the Atlas Mountains in North Africa; the Rif-Betique range in southern Spain and two coastal strips of Morocco and Algeria; Maritime and Ligurian Alps of the French-Italian border; Tyrrhenian Islands; southern and central Greece; Crete; southern Turkey/Cyprus; Israel and Lebanon; Cyrenaica in Libya; and the Canary/Madeira Islands. These 10 areas cover about 22% of the Basin's total area, yet account for almost 5 500 endemic plants, i.e., about 47% of total Mediterranean endemics (Médail and Quézel 1999). Considering the redefinition of the hotspot boundary, the inclusion of the Cape Verde Islands (4 071 km²) and the Azores (2 407 km²) with the Canary/ Madeira Islands to form an expanded Macaronesian mini-hotspot appears warranted. Clearly, these are priority sites for conservation of these plant components of Mediterranean-Macaronesian biodiversity.

As with the other Mediterranean-climate hotspots, diversity and endemism among vertebrates is much lower than for plants (Blondel and Aronson 1999). The mammal and bird faunas are largely derived from extra-Mediterranean biogeographical zones, with Eurasian and African elements dominating the mammal fauna, whereas Eurasian and semiarid southern elements dominate the avifauna. The North African mammal fauna has closer affinities with tropical Africa than with the Mediterranean Basin. On the other hand, the reptile and amphibian faunas comprise mainly Mediterranean species, and have higher levels of endemism. Many endemic species and genera are archaic lineages, which have probably remained unchanged since their differentiation before the Late Tertiary onset of Mediterranean climate conditions.

The present number of land mammals in the region is about 224, of which 25 are endemic, including several standouts like the Barbary deer (Cervus elaphus barbarus); Barbary macaque (Macaca sylvanus, VU); Mediterranean monk seal (Monachus monachus, CR), now thought to number fewer than 400 individuals; and Iberian lynx (Lynx pardinus, CR), the world's most threatened felid with no more than 250 individuals surviving. The region's avifauna includes about 497 regularly occurring species of which only 32 are endemic, among them two Critically Endangered species: the Raza Island lark (Alauda razae), found only on that island in the Cape Verde Islands; and the Madeira or Zino's petrel (Pterodroma madeira), which has an estimated breeding population of 20–30 pairs in the central mountain massif of Madeira. A few small portions of the hotspot also appear as priorities in BirdLife International's recent global analysis of Endemic Bird Areas (EBAs) (Stattersfield et al. 1998), namely Cyprus, Madeira, and the Canary Islands (with eight species confined to this EBA), and Cape Verde.

Endemism is much better developed in reptiles, with 228 species, 77 of which are endemic; there are also four endemic genera, namely Algyroides, Trogonophis, Macroscincus, and Gallotia (the latter being a genus of lizard unique to the Canary Islands). Of the 86 species of amphibians in the hotspot, 27 are endemic. Reptile diversity is highest in the drier, eastern part of the European portion of the basin and in North Africa, whereas the opposite is true of amphibians. For both groups, the Mediterranean Basin is an important center of diversity and endemism for some families. These include, for amphibians, the Discoglossidae (11 of the world's 12 currently recognized species, with nine endemic) and, for reptiles, the Lacertidae (63 species, or 23% of the world total; 25 endemic), Testudinidae (five species, 16% of the world total; one endemic, Testudo weissingeri), and Viperidae (19 species, 8% of the world total; five endemic).

The inland fishes of this hotspot represent small subsets of the rich Eurasian and African fish faunas from which they are isolated. Consequently, the fauna is species-poor (216 native species), although it includes 63 endemic species, six endemic genera, and even an endemic family, Valenciidae, the tooth carps of the Iberian and Greek peninsulas. These two peninsulas provide the primary centers of fish endemism in the hotspot, together containing 86% of its endemic fishes.

The present human population of the Mediterranean Basin is some 300 million and increasing, and the impact of a long history of human assault on Mediterranean ecosystems has been huge. Perhaps the most severe transformation has been the conversion of forests, especially primeval deciduous forests, to agricultural lands, evergreen woodlands, and maquis. Tourism, too, has had a serious impact on semi-natural areas in western and southern Turkey, and in Cyprus, Tunisia, and Morocco, a list that may shortly be joined by Greece among several other countries, particularly as concerns Mediterranean Islands such as the Balearics, Corsica, Sardinia, Sicily, Crete, and the Canary and Madeira Islands. Although reforestation is occurring in some of the more developed areas of the Basin, e.g., southern France and parts of northern Spain, Italy, and Croatia, the pace of land degradation is accelerating in North Africa, where human populations are still increasing at a rapid rate (2.1% per year, way higher than the 1.6% for developing countries as a whole, and the population could surge from 150 million in 2003 to 206 million in 2025) (Population Reference Bureau 2003).

Much of the Basin's current vegetation reflects the influence of humans for several millennia. To this profound extent, many, if not most, present-day landscapes are an example of co-evolution between nature and humans. It would be erroneous in the case of the Mediterranean to regard only purely pristine vegetation as “worthwhile” primary vegetation in the sense of undisturbed original vegetation when, even by the year 1000, much of the Mediterranean Basin was bearing widespread marks of human activity. For this reason, today's environments have been divided into pristine (extremely rare, 1%–2%), semi-natural (fairly frequent, albeit in small patches, for the most part uncultivated, but somewhat managed, 20%–25%), and sub-natural (the predominant form, with limited natural vegetation and of contrasted relevance to the conservation of biodiversity, 73%–79%) (Naveh and Kutiel 1990).

The Mediterranean Basin Hotspot, therefore, emerges as one of the hottest, having exceptionally high plant endemism, and one of the lowest percentages of natural vegetation remaining in pristine condition (no more than 5%) of any hotspot. Furthermore, the hotspot has a surprisingly low protected area coverage, with only 4% under some form of protection, and protected areas in IUCN categories I to IV make up an extremely low 1% of the surface area of the hotspot.

Protected areas have had a long history in the Mediterranean. As much as 2 000 years ago, several societies set aside areas for protective purposes or, rather, as “resource reserves,” some of them surviving to the present time. They were “developed as an ancient acknowledgment of the scarcity of renewable resources and a need to conserve and use them widely in support of sustainable rural economic development” (Sulayem 1994). Today, most countries of the Basin are planning substantial increases in their protected area systems. This applies especially to the Levant countries of Turkey, Syria, and Lebanon. Because of the demands of agriculture and other activities that absorb large tracts of natural environment, many protected areas are small, but a good deal is being accomplished through more flexible arrangements of Biosphere Reserves, especially in those areas where state authorities recognize their value. Biosphere Reserves seek to safeguard natural environments in areas where there is a moderate degree of intrusion by humans. There is also a host of conservation efforts under way, such as the European Union's Habitats Directive, popularly known as Natura 2000, which requires the Mediterranean countries of the European Union to identify the more important natural sites and to formulate conservation responses. Indeed, there is still much to be hopeful about in this hotspot, where there is so much biodiversity at stake.

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