The goal of the project is to document particular vegetational types of the everhumid warm temperate area of the Colchis at the eastern Black Sea coast. The area is characterised by mild winter temperatures, and evenly distributed high amounts of precipitiation, which exceed 2500 mm per year in many regions, and more than 4000 mm in the most humid hinterland of Batumi, Kobuleti.The Colchic lowlands are outstanding for the co-occurrence of distinct vegetational types. The most important are:
1. Well drained forests with Fagus sylvatica ssp. orientalis and accessory broad leaved-deciduous species in the canopy layer, evergreen shrubs and perennial herbs in the understorey, such as Rhododendron ponticum, Prunus laurocerasus, Ilex colchica, Buxus colchica, Daphne pontica, Ruscus colchica, Epimedium colchicum, and Smilax excelsa.
2. Poorly drained forests, partly natural levees and backswamp forests, dominated either by Alnus barbata or by Pterocarya fraxinifolia - Alnus barbata - Carpinus caucasicus - (Quercus hartwissiana - Ficus carica) and others. Evergreen shrubs are missing. Lianas are abundant, for example Smilax excelsa, Periploca graeca, Vitis vinifera, Hedera helix, H. colchica, Lonicera japonica, and Polygonum perfoliatum.
3. Marshes and peat bogs intermingling with above mentioned forest types.
3. Coastal dunes.
Mountain forests of the hinterland resemble lowland forest type no. 1, but contain a number of endemic species such as Rhododendron ungernii and R. smirnowii, and Quercus pontica, which was a widespread European Tertiary element.
Special attention is drawn to the ecological amplitude of Tertiary relict species. In order to evaluate this, outposts of Colchic species in the Borjomi area and in east Georgia, Lagodekhi area, as well as in the Turkish Pontic Range, are studied. One characteristic feature of many relict taxa, for example the genus Zelkova, is their ambivalent ecological behaviour, such as the occurrence in warm humid forest types as well as in summer-dry mediterranean vegetation types. The same can be observed in some animals, such as the genus Mertensiella.
During the Pleistocene period a number of taxa that were widespread during the Tertiary became extinct in Europe, while most survived in SE North America and/or SE Asia. Models on European Tertiary vegetation and climate are therefore mainly based on these vegetations. We want to study how the few Tertiary relict species in western Eurasia occupy niches that were in pre-Quaternary periods inhabited by many more species. A sort of vicariance is apparently present, for example Alnus barbata could be viewed as a vicarious species to the fossil taxa of Taxodium and Nyssa. Moreover, the presence of free niches is demonstrated by the enormous spreading of ‘exotic´ elements in the Colchic area. Therefore, (1) the mosaic-like pattern of different vegetational types, (2) the co-occurrence of zonal and azonal elements, and (3) the co-occurrence of vegetation units normally confined to distinct vertical belts are supposed to reflect well European conditions of the Late Tertiary.
Coworkers:
Norbert Frotzler, Vienna
Nino Davitashvili, Tbilisi
Find out more:
Temperate dry forests of Eastern Transcaucasia - Tertiary relict vegetation of a “pre-Mediterranean" type?
Print page
