Excursus : Vegetation, natural history and geo-politics (2)

There are times when to observe Turkish politics may be tiresome and frustrating, particularly if you feel some sympathy for the Turks (in a broad meaning), the main victims of these politics. As an observer, you can’t do much about it. So sometimes it may be better to leave for a stroll in the greenery.

 First part

IV. Different types of relics.

It may be noted that it is Georgia which is mentioned by far the most frequently when the issue is Caucasian endemism. It’s not really wrong, but Azerbaijan is even richer in that respect. One might guess that there is an effect of the Muslim-malus which is frequently appearant in Western (European) perspectives, but this is not necessarily the case. I dare say that it would be rather atypical for botanists or zoologists. It cannot be excluded altogether because this malady seeps in from all the traditional fields of the humanities.
But another issue is also involved : In Azerbaijanian endemism, the still considerable share of endemic woodland species is considerably outnumbered by steppe and semi-desert dwellers.

An often-heard explanation for the wealth of Anatolia in terms of species numbers is that three major phytogeographical regions - Euro-Siberian, Irano-Turanian, and Mediterranean - meet there, each covering wide regions. Whereas this is true in a strictly recent-geographical meaning, it drops the historical aspect. Therefore it needs some correction to fit, for instance, in the concept of evolution. Those phytogeographical types mingle in Europe at least since the Miocene, since some twenty million years. There is another reason for Turkey’s abundance of species, and especially for their wealth in endemics. Which we may extend to Caucasia.

Relics and endemics are not restricted to the temperate forest and Mediterranean vegetation, but occur even more in steppe and other vegetation types, including tundra and semi-desert. The rate of endemism in Turkey’s temperate forests is just around ten percent (which is still high), whereas it is as high as forty percent and more in steppe species, and the Mediterranean element is intermediate. How come ?

Relics and endemics occur most frequently when a population is cut off from the main area of the species. Either they simply retain the old features (relic endemism in a strict sense), or they develop further, but independently and differently from the mainstream of the species dwelling in another geography. Then they are “progressive” endemics, although they may still be relics of a once wider and coherent distribution of the initial species. It’s not always possible to decide which exactly is the case. But mountains are a suitable terrain for both, because they are somewhat isolated from each other as well as ecollogically different from the plains, and because each has a wide variety of ecological conditions (northern or southern slopes with different insolation, deep or shallow soils, different precipitation regimes east and west, different accessibility for grazing or pollinating animals, etc.). More variety of effects may result from deep canyons and gorges.

So today the Alps have a lot of relics and endemics, such of tundra or taiga, and even more of steppe type – largely stemming from late glacial or early postglacial times, because there were virtually no plants in the Alps during the high glacial. As the central Alps are dryer than the fringes, there are more steppe elements in the center. Anatolia was much lesser glaciated than the Alps even in high glacial times, and in turn has not only more, and sometimes more isolated mountains, but also a much wider center. Obviously, much of the Anatolian endemism is older than the last glacial. Anatolia, and even the Caucasus, is poor in tundra and taiga elements, but immensely rich with respect to the steppe flora, and no surprise, particularly in the higher mountain steppes (and alpine meadows). Here, the temperate and Mediterranean forests and shrublands are in an intermediate position.

Between three seas (Pontic, Aegean and Mediterranean) north, west and south, and (by nature) the East-Anatolian woodlands (now however mostly cleared and overgrazed since the Bronze Age), even the Central-Anatolian steppe had relic character in post- and interglacial periods, and perhaps already in some M^io- and Pliocene periods as well. And each mountain has some possible refuge high up or down below, and in addition some special habitats for rock-dwellers. In the Euxinic corner of Georgia, some steppe plants, which immigrated in a dry period, “were taken by surprise” when annual rainfalls started to go up to more than 2.000 l per square meter, which enabled some of them to grow to rather giant forms.

The highland of Armenia is basically an extension of the East-Central-Anatolian steppe and wood-steppe region, with some share in the Euxinic forest region, but becoming more of Iranian rocky dryland type in the southeast, like the Azerbaijanian exclave of Nakhchivan. To the northwest, much of Georgia is the very heart of the Euxinic temperate rainforest region extending to northeastern Turkey, but also becomes quite dry towards the east. There, in Azerbaijan, we still find the Euxinic forest in the western mountains, and more Hyrkan type forest towards the eastern foothills of the Great Caucasus and especially near the southern border (Talysch mountains and Lenkoran plain). The riverine-alluvial vegetation in the west of the country is also of temperate European type. But on the eastern Kuras River plains and the lowlands of the Caspian Sea, semi-desert and dry steppe prevail. There are some fragments of riverine forest, and planted trees may grow rather well (by nature it may be a savanna type region). But here we enter the region where the typical European woodland flora comes to an end while typical “Central-Asian” (more correctly Central-Eurasian) dryland starts.

 To be continued.