Professor, Ilia State University, Georgia
Series: Wildlife Protection, Destruction and Extinction
The Caucasus is a mountain region located at the edge of Europe and Asia, between the Black and Caspian seas. In spite of limited geography and mostly temperate climate, diversity of natural landscapes, plant and animal species, and cultivated plants is unusually high. For these reasons, the Caucasus has been included in the list of global biodiversity hotspots. Proportion of endemic species of higher plants and terrestrial vertebrates varies between 15-30% for individual groups according to different authors, with a vast majority of some taxonomic groups such as terrestrial snails exceeding 80%. There is a number of relict plants and animals, whose relatives are not found in the neighboring parts of Eurasia, but in the distant regions throughout the northern Hemisphere.
Simultaneously, the Caucasus is known as an area of early settlements of hominids and the area of ancient agriculture. High proportion of endemic and relict species is unusual for a continental, non-tropical region. The author describes the biodiversity of the Caucasus region, starting from the Mesozoic time and ending with the current situation, and tries to analyze the evolutionary factors that shaped this diversity. Since the Caucasus is not an island (and most of its parts were associated with the Eurasian continent), the main reasons driving spatial isolation and speciation, were long-term climate changes, specifically gradual decline of temperature and humidity and landscape transformation since last 15 millions of years. This factor, together with changes of land shape in Cenozoic time, caused isolation of forest animals and plants and their transformation into unique species, in parallel with adaptation to new habitats.
Although fossil evidence of the evolution of the Caucasus biodiversity is discussed, the main focus is on the recent molecular genetic data. This information helps to identify closest relatives of the endemic forms outside the studied region and to reconstruct the process of separation among evolutionary lineages and further evolution. At last, types of animal and plant ranges are discussed from the evolutionary perspective. The book contains multiple examples of evolutionary patterns and distribution histories of diverse organisms, including forest trees, evergreen shrubs, snails, frogs, salamanders, lizards, grouses, mice, shrews, hedgehogs, bears, and many others. The book is illustrated with multiple images of discussed species of plants and animals, landscapes, geographic maps, and diagrams that help to understand the discussed patterns. (Imprint: Nova)