Location and General Description
The Caucasus Mixed Forests are located at a biogeographical crossroads where flora and fauna of at least three biogeographic provinces converge - Central/Northern Europe, Central Asia, and the Middle East/North Africa. Climate is temperate but fluctuates by elevation, that varies from 0 to 5,642 m a.s.l. (Mount Elbrus, Europe’s highest point) and by regions: air temperature is changed on the average of 0,65oC per 100 m altitude, annual precipitation – from 1500-2000 (up to 4500) mm in the western, Colchic section to 600-1000 mm in drier parts of eastern and southern sections. Temperate mixed forests concentrate within the mid-zone of mountains (400 - 2,200 m) and cover about 70% of ecoregion’s area. Forests are predominantly broad-leaved (about 85 %) with domination of Georgian oak (Quercus iberica) and hornbeam (Carpinus caucasica) – up to 1000-1200 m a. s. l., sweet chestnut (Castanea sativa) – in humid western part (500-1000 m), Oriental beech (Fagus orientalis) – 1000-1500 (1800) m, ., which in drier parts is replaced by oriental oak (Quercus macranthera). Timberline is mainly created with crooked-steam forests/elfin woods of birch species (Betula litwinowii, B. raddeana, etc.) in humid parts and with woodlands of oriental oak and Caucasian pine (Pinus kochiana) in drier parts – 1800 (2000)-2600 m. Coniferous forests mainly composed of fir (Abies nordmanniana), spruce (Picea orientalis) – 1500 (1200) – 1800 (2000), and Caucasian pine (from 800-1000) . Grassland ecosystems occur from forest line to snow cover and glaciers and composed by tall herbaceous vegetation of grass and forbs (1,800- 2200 m), various subalpine (1800-2500 m) and alpine (2500-3000 m) meadows, alternating with thickets of Rhododendron caucasicum (2000-2800) and rock scree vegetation. Open sub-nival plant communities found in rock and talus substrates at the elevation of 3000-4000 m (Nakhutsrishvili, 1999; Zazanashvili et al., 2000).
The Caucasus mixed forests is a unique ecoregion due to its evolutionary phenomena. The eight ecoregions bordering it differ significantly with regard to climatic conditions and species composition. Apart from this, the area partly coincides with the Colchic refuge of Tertiary Flora (eastern part of catchment basin of the Black Sea). This is the most important refuge and relict area of the arctotertiary forests in West-Eurasia. These are the only places in this part of the World where warm-temperate deciduous forests existed without interruption since the Tertiary. Even now, many relict forms still appear as dominant or co-dominant in a number of plant communities, such as oaks (Qurcus hatwissiana, Q. pontica), zelkova (Zelkova carpinifolia), birchs (Betula medwedewii, B. megrelica), rhododendrons (Rhododendron ponticum, Rh. ungernii, Rh. smirnowii, etc), chery-laurell (Laurocerasus officinalis), Colchic holly-tree (Ilex colchica), etc. (Dolukhanov, 1980).
Because of such conditions (influence from different biogeographic provinces, existence of refuge), the speciation rate here was high, and accordingly, it has one of the highest levels of endemism in the temperate world with 23 percent of vascular plants and 10 percent of vertebrate animals endemic to the region. In addition to location, landscape and habitat diversity favors to high species richness - about 5,000 vascular and 7,000 lower plants (including high mountains), and 700 vertebrate animals are found in this ecoregion (Georgia 1996, Azerbaijan 1998, Armenia 1999).
Fauna richness is high; characteristic mammals include the East Caucasian tur (Capra cylindricornis), West Caucasian tur (Capra caucasica) – endemic species of the Greater Caucasus range, chamois (Rupicapra rupicapra), Caucasian red deer (Cervus elaphus maral), wild goat (Capra aegagrus), mouflon (Ovis orientalis gmelini), brown bear (Ursus arctos), gray wolf (Canis lupus), lynx ( Lynx lynx), European otter (Lutra lutra), and critically endangered Caucasus leopard (Panthera pardus ciscaucasica).
Many species of avifauna is found in this ecoregion including such endandered species as the golden eagle (Aquila chrysaetos), and lammergeier (Gypaetus barbatus), restricted species such as the Caucasian black grouse (Tetrao mlokosiewiczi), and Caucasian snowcock ( Tetraogallus caucasicus). Other characteristic species include great rosefinch (Carpodacus rubicilla), Guldenstadts’ redstart (Phoenicurus erythrogaster), gadwall ( Anas strepera), whooper swan ( Cygnus cygnus), common pochard ( Aythya ferina), Greater Scaup ( A. marila), common goldeneye ( Bucephala clangula), and Dalmatian pelican ( Pelicanus crispus).
Fauna of reptiles and amphibians includes the restricted range endemic species of Caucasian salamander (Mertensiella caucasica), Caucasian viper (Vipera kaznakovi) and Caucasian parsley-frog (Pelodytes caucasicus).
Urban and rural development have been converted most of lowland forests to agricultural and development lands. About 5% of the region’s area have protective guidelines. Principal protected areas are Borjomi-Kharagauli National Park, Lagodekhi and Tusheti Strict Nature Reserves in Georgia, Caucasus Biosphere Reserve in Russia, and Zakatala Reserve in Azerbaijan. The gaps in the reserve network were not assessed. Approximately 35% of mountain forests mainly remain in a natural state, but current attempts to develop commercial forestry in the region along with socio-economical crisis, which stimulates raising of the demands of local population on firewood is a potential threat to these habitats.
Types and Severity of Threats
Unsustainable forest use, including poor management and illegal cutting in combination with uncontrolled timber export, create main threats for forest ecosystems. Overgrazing is a major cause of habitat degradation at upper line of forests and grasslands (Gokhelashvili et al. 1999).. Overexploitation or poaching of game and economically valuable species is another very significant threat to biodiversity here. Georgia and Armenia have developed national Biodiversity Strategy and Action Plans (Armenia 2000, Georgia 2000), where conservation of these habitats is listed as one of the priority actions.
Justification of Ecoregion Delineation
The Caucasus ecoregion boundary was derived from the DMEER (2000) unit of the same name. It consists of altitudinal belts of hornbeam-Oriental beech forests, montane fir forests, subalpine and oro-Mediterranean vegetation, and alpine vegetation (Bohn et al. 2000). As a result of fitting the Guidotti (1986) and DMEER systems together, the easternmost section of the subhumid Black Sea mountain conifer forests vegetation unit (Guidotti 1986) and the extreme eastern portion of mountain Black Sea deciduous mixed forest (ibid.) have been included in the Caucasus mixed forest ecoregion.
Armenia. 1999. Biodiversity of Armenia. First National Report. Ministry of Nature Protection, UNDP, Yerevan.
Armenia. 2000. Biodiversity strategy and action plan. Ministry of Nature Protection, Yerevan.
Azerbaijan. 1998. National environmental action plan. State Committee on Ecology, Baku.
Bohn, Udo, Gisela Gollub, and Christoph Hettwer. 2000. Reduced general map of the natural vegetation of Europe. 1:10 million. Bonn-Bad Godesberg 2000
Dolukhanov, A. G. 1980. Colchic understorey. Publishing House "Metsniereba", Tbilisi.
Georgia. 1996. Georgian Biodiversity Country Study Report. UNEP, Ministry of Environment, and NACRES. Tbilisi.
Georgia. 2000. Biodiversity Strategy and Action Plan. Ministry of Environment, the WB, Tbilisi.
Guidotti, G., P. Regato, S. Jimenez-Caballero. 1986. The Major Forest Types in the Mediterranean. World Wildlife Fund, Rome, Italy.
Nakhutsrishvili, G. 1999. The Vegetation of Georgia (Caucasus). Braun-Blanquetia,15, Dipart. di Botan. ed Ecol. dell’Univers.-Camerino et Station de Phytosoc.-Bailleul, Printed by Centro Audovisivi e Stampa, Camerino.
Zazanashvili, N., Gagnidze, R. and Nakhutsrishvili, G. 2000. Main types of vegetation zonation on the mountains of the Caucasus. Proceedings IAVS Symposium, IAVS; Opulus Press Uppsala. Printed in Sweden.
Prepared by: Ramaz Gokhelashvili
Reviewed by: Nugzar Zazanashvili