Conceptual scenarios of the influence of changes in the Lake Baikal level on the biota of coastal ecosystems
N.G. BORISOVA, O.A. ANENKHONOV, S.V. ZAITSEVA, A.I. STARKOV, O.P. DAGUROVA, L.L. UBUGUNOV
Institute of General and Experimental Biology, Siberian Branch, Russian Academy of Sciences, Ulan-Ude, Russia
Keywords: ecological conceptual models, microbial communities, vegetation cover, fauna, hydrological factors, biota response
Abstract
It is established that when making decisions concerning the level management in Lake Baikal which possesses a unique biota and unprecedented hydrological parameters, yet being used in the mode of a reservoir of long-term regulation, it is necessary to take into account the requirements permitting the lake ecosystems to operate sustainably. Such requirements can be defined in the process of developing conceptual scenarios reflecting the impacts of various factors on the biota with due regard for the relationships between them and ecosystem components. We examine the possible factors of the impact of changes in water level on three components (microbial communities, vegetation cover, and fauna) of coastal ecosystems of Baikal and suggest relevant conceptual scenarios. A number of mechanisms of the influence of the water level on microbial communities are highlighted, and direct and indirect impacts on structural and functional characteristics of microbial communities of Baikal in different conditions of water levels are suggested. A two-level framework of factors affecting aquatic and terrestrial coastal vegetation with rising and falling water levels has been developed, and the influence of each factor was qualitatively assessed. Potential threats for the fauna (waterfowl and near-water birds were involved as a case) generated by the water level fluctuations were outlined in connection with biotopic and trophic relationships. In general, the heterogeneity and multidimensional character of the biota responses to the water level fluctuations has been revealed. It is emphasized that environmental integrity of ecosystems of fresh-water lakes, and the character and degree of impact on the biota from changes in water level of lakes still represent a “white gap” for the modern science. This is why the general schemes for ecosystem-based management of lakes have still not been developed.
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