The ecology of Olkhon island (Baikal lake) water bodies under the changeable conditions

In our days the recreational impact on ecosystem of Olkhon Island, the largest island of Lake Baikal, is rapidly growing. Drastic reduction of the area and depth (the so-called ageing) of lakes has been recorded on Olkhon Island. Ecological investigations were performed in two lakes in 2014-2015. We studied physical and chemical parameters of the lakes, species diversity, structure and seasonal dynamics of planktonic rotifers and crustaceans. Species and dominant compositions of Lake Nur and quantitative characteristics of zooplankton were compared with the data obtained 40 and 60 years ago. We determined the dominance of species resistant to anthropogenic impact. Besides natural “ageing” of the lakes (warm and dry period in Pribaikalye region), the lakes are also subject to intensified activity of tourists and local population. All these facts can make the current situation irreversible.