Biodiversity of Island Ecosystems of the Northern and Middle Caspian and a New Outlook at the Islands Age and the Caspian Sea Level Regime

Abstract

Species diversity of some biota taxonomic groups of the larger islands (Chechen, Tyuleniy, Nordovyy, Kulaly) of the Middle and Northern has been established by the research expeditions of 2009-2013. Endemic taxa of species and subspecies rank have been found in the flora and fauna of this island group. The results of the GIS simulation (of the map), showing the water surface configuration under the sea level lowering have been presented and different approaches to explain the fluctuations in the Caspian Sea level and the mechanisms of islands and evolution and depositional bench lands of the Northern and Middle Caspian have been briefly described in the article. The supposition on the presence of island firm land throughout the holocoen (even during the highest sea level) has been made on the basis of analysis of the island biota composition and the causal explanation of the endemic taxa presence in the water area of the Middle and Northern Caspian.