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In the year 2000 about 9300 species of vascular plant were known for the area of the Turkish Republic. By comparison, Europe as a whole contains only about 24% more species (about 11500), despite having thirteen times the area.〔(【引用サイトリンク】url=http://www.allaboutturkey.com/turkfauna.htm )〕 The most important reasons for Turkey’s high plant biodiversity are believed to be the relatively high proportion of endemics in combination with a high degree of climatic and edaphic variety. == Endemism == DAVIS & al. (1988) calculated that nearly one third or Turkish plant species (30,6%) is endemic to Turkey and the nearby Aegean Islands. For Austria the respective value is meagre 1,56% and for the British Isles it is still lower. Moreover, none of the endemic British species is taxonomically remote from a non-endemic species. An ultra-conservative taxonomist might therefore unite all the endemic species with none-endemic ones, thus reducing endemism on the British Isles to 0%. On the other hand, rates of endemism are also highly dependent on the surfaces of compared areas and their delimitations. In order to achieve better comparable data we might unite the surfaces of Germany and France, thus obtaining an even larger area than Turkey. But the estimated proportion of endemics still would remain much lower, with Germany alone having about the same low proportion as Austria. One reason for this relative importance of endemism in the Turkish flora is the mountainous and at the same time rather strongly fragmentised surface of Anatolia. In fact the Anatolian mountains resemble archipelagos like the famous Galapagos Islands. Since Darwin we know that geographic isolation between islands or separated mountains is an important means of speciation, leading to high spatial diversity. For Anatolia this assumption is conformed by concentrations of endemism on highly isolated and relatively old massifs as Uludağ or Ilgaz Dağ, whereas very young volcanic cones as Ercyes Dağ or Hassan Dağ are surprisingly poor in endemics. . As the evolution of local endemics is a rather lengthy process, we have to consider also the different histories of central or north European mountains and the Anatolian ones. During each of the glacial periods the former were covered by thick shields of permanent ice. Thereby pre-glacial endemism was mostly destroyed and the forming of neo-endemics hindered. Only less glaciated, peripheral areas, the so-called “massifs de refuge”, offered suitable conditions for the survival of local endemics during glacial periods. In Anatolia ice cover during Pleistocene glaciations always remained restricted to the highest peaks. As a logical consequence, species with small distribution-areas are a rather common phenomenon in many parts of the country. In other words: Anatolia as a whole is a big “massif de refuge”, showing all degrees of past and recent speciation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Flora and vegetation of Turkey」の詳細全文を読む スポンサード リンク
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