ANNALS OF AGRARIAN SCIENCE, vol. 9, no. 1, 2011 ИЗВЕСТИЯ АГРАРНОЙ НАУКИ, Том 9, Ном. 1, 2011 ----------------------------------------------------------------------------------------- AGRONOMY AND AGROECOLOGY АГРОНОМИЯ И АГРОЭКОЛОГИЯ THE RESULTS OF BIOGEOGRAPHICAL STUDY OF THE ARCTOARCTO----TERTIARYTERTIARY REFUGIA (COLCHIS AND TALYSH) OF SOUTHERNSOUTHERN CAUCASUS A.M.Gegechkori Ivane Javalhishvili Tbilisi State UniversiUniversitytytyty,, Department of Biodiversity 3, Ilia Chavchavadze Ave.,Tbilisi, 0128, Georgia; [email protected] Received: 17.11.10; accepted: 09.01.11 South Caucasus two regions Colchis and Talysh are one of the species-rich refugia for many Tertiary relict organisms – plant and animal species in Western Euroasia. Due to two regions peculiar geography, abiotic factors and natural history both refugial centres of South Caucasus are of particular interest for biogeographical studies. However, present article is a first attempt to a such interdisciplinary investigation. We analysed patterns of floristic and faunistic richness, endemism, including relict endemics, modern distribution of close relict species in other countries and regions of Northern Hemisphere, specificity of formation of two harbour territories of Tertiary organisms, palaeo-ecological data of the Black seacoastal and Caspian seacoastal regions, comparative analyses of the specificity of altitudinal zonation of Colchis and Talysh, at the same time comparing the structure of surviving in mentioned shelters two ancient elements of native flora and fauna – a) tropical-subtropical, b) organisms of the Arcto-Tertiary origination. Finally, critical analyse was dedicate to two refugial centres, which by some botanists are recognized as moist subtropic biocenosis. OBJECTIVES AND METHODS The overview of biomes and comperative analyse of two famous rafugial centres of the Caucasus – Colchis and Talysh is first and foremost the result of the long-term comprehensive (faunistic, floristic, biogeographical) studies of the wildlife of the Caucasus by the author of present articles cycle. We focussed first of all on the psyllids (Insecta: Hemiptera, Psylloidea). This group of insects constitude a highly indicative group for environmental research [1-3]. Psyllids are small phloem feeding insects that are typically monophagous (feed on a single plant species) or olygophagous (feed on a few relates species). The data were gathered during almost thirty years (1962-1990) of field work in all biomes and altitudinal zones of the natural-historical regions of the Caucasus (see schematic maps 1,2.), and in all vegetation seasons (early spring – late autumn). During the years 1990-2008 similar excursions were made but with lower intensity. Data for interregional comparison were collected in Middle Asia, Siberia and the Russian Far East (1981- 1991), in Asia Minor (1995-1998, 2006), and in other parts of the world (1986, 1989, 2000-2003). The results are presented in various monographs and articles [2-9]. 1 Sch. map 1. Sch. map 2. As it is broadly known, refugia are the regions of the Earth, where living organisms endured severe climatic and orographic fluctuations and as a relict forms are still survived. Hence, these shelters of the archaic organisms consist of useful data for solving important problems of biogeography, evolutionary biology, taxons genesis, etc. Each refugia of the Earth have their specific historical, geographical and abiotic peculiarities by what they in historical past turn into shelters for ancient organisms. For instance, how does California preserve Mediterranean proper maquis communities, known today as a Madro- Tertiarian flora, or New Zealand keeps a Mesozoic Antarctic’s Gondwanian formations with species of tree ferns, south beeches ( Nothofagus spp.), south conifers ( Podocarpus spp.), etc? The reasons are different. Their own historical and palaeecological-geographical reasons have Transcaucasia’s two famous refugia – Colchis and Talysh with present-day communities, for which not seldom is used the term – “subtropic”. In some regions of the Caucasus, namely, in Colchis, Talysh, and partially in river Alazani valley (Kakhetia, East Georgia), owing the warm and moist climate survived considerable number of species – the representatives of ancient Tertiary’s origin plants and animals. Among the Caucasus biomes, the floristic and faunistic diversity and infrequency (relict and endemic species) of forests of mentioned two refugia, are one of the most striking feature of this region. With respect to vegetations of this region this phenomenon have long been recognized, intensively studied and discussed [10-20]; the same interests have increasingly fascinated regarding to fauna [21-26,6]. What do we consider under Tertiary relicts in South Caucasus? In moderate climate belt of the Northern Hemisphere is represented broad-leaved deciduous (summer-green) forest’s zone (biome). In biogeographical literature it is determined as a Temperate Broad-Leaf Deciduous Forest (TBDF). By geobotanists this flora are proposed as the Arcto-Tertiary Geoflora (ATG) [27-30]. In Russian language literature it is indicated as a Turgayan Flora [31]. This term derives from Turgay Hollow (Kazakhstan), where in 1929 Russian paleobotanists A. Kryshtofovich [31] and then S. Zhilin [32] from Oligocene deposits has described the most characteristic fossil remains of TBDF complex: chestnut, beach, zelcova, walnut, hazelnut, etc.; from gymnosperms to mentioned complex belongs Sequoia , Metasequoia , bog’s cypress, etc. Sometimes TBDF complex mentioned as a Nemoral Flora (the term nemoralis – means “forest”) [33,34,26,7]. Broad-leaved deciduous forest of a particular floristic composition evolved in the Rocky Mountains [29] during Eocene time, and lately in Himalayas [35], persisted there during the Early Tertiary and, in response to gradually cooling climate, migrated southward during mid- Tertiary into the middle latitudes, where their most large territories of these forests persist today in east-central Asia and south-eastern North America [35,36]. In the Oligocene Epoch this ancient mesic woody flora was represented as a circumpolar distributed biome. Originated within depth of subtropical evergreen moist forests, the Arcto- Tertiary’s forests woody elements adaptation to initial more or less clearly expressed global cooling climate were foliage drop in coldest season of the year. About 15 million years ago, climatic cooling took place due to northward drift of both northern continents after break up of Laurasia in the Cretaceous Period. Cooling apparently let the sorting out of the gymnosperms from the angiosperms. The former one became concentrated 3 in higher latitudes as a boreal (taiga) forests [37]; Angiosperms, preferring a milder climate, became the TBDF. These forests were traditionally compared with forests of the Tertiary Period [38]. As it was mentioned above, ATG was supposed to have been widespred from higher latitude throughout the Northern Hemisphere [39,35,36]. Chaney [39] believed that severe climate during the Quarternary Period eliminated the ATG entirely from many region of the Northern Hemisphere. But following to J.A. Wolfe [40], changes of the Late Tertiary and Quartenary climate caused local adaptations rather than migrations of intact plant comities from one latitude to another as Chaney hypothesized. More, the same author challenged the geoflora concept and argued that a uniform broad-leaved forest never existed. His analysis of the paleobotanical data shows that Tertiary floras were diverse, with evergreen gymnosperms such as Sequoia dominant, and evergreen angiosperms present elsewhere. Continental drift of Laurasia’s megacontinent has caused the separation of North America from Euroasia [41]. This separation of two continents’ nemoral flora in the most impressive way attracts Arcto-Tertiarian floras complexes of eastern Asia and North America. This disjunction in the TBDF, leads to the contemporary configuration of distribution pattern of the biome. The close floristic, partially faunistic relationship between the both regions has long been recognized and discussed [42-45]. Mentioned and other macro-disjunction areas have been triggered the origination of new direction in biogeography – vicariance (mobilistic) biogeography. In western Euroasia, a species-poor broad-leaved forest reflects widespread extinctions during the Pleistocenes Ice Ages. At present, the nemoral forest (sensu lato) consist of all those biocenoses which in the Northern Hemisphere are occupying a broad-leaved forest biome (an indicator of this biome is considered deciduous species of oaks). Within this communities participate some warm climate loving conifers – tsuga, yew tree, etc. [31,46,36,29,30]. With respect to the Turgai fauna, it belongs to Oligocene as well. The Russian paleontologist A. Borisiak [47] was first scholar, who described from the same Turgai Hollow the complex fauna closely connected with nemoral forests. The most characteristic species of this fauna is giant unicorn – Indricotherium . According to Dolukhanov [20], some of representatives of the Arcto-Tertiarian flora grow in dispersive way, as a seldom met specimen or groups in large territories (f.e., Taxus baccata ), some of them preserve in local places, strictly restricted in refugial areas. Among them should be mentioned eastern part of the USA (the Appalachian Mountains), the Russian Far East, and Atlantic Ocean coast countries in South Europe. Nemoral communities of East Asia and the Appalachian