Structural-dynamic organization of forests in Lake Baikal basin
V.I. VORONIN, A.P. SIZYKH, V.A. OSKOLKOV
Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
Keywords: polydominant forests, river basins, hydroregimes, period of flooding, Western Cisbaikalia, Eastern Cisbaikalia
Abstract
Presented are the results from studying the structural-dynamic organization of the forests in basins of large rivers flowing into Lake Baikal and having a considerable influence on changes in its hydrologic regimes. It is known that annual discharge of rivers essentially depends on the state of the forests growing in their basins. The stability of the hydrologic regime of the rivers accounting for the main volume of water transported into the lake is directly dependent on the functional properties of forests. The preservation of the environment-protective and water-regulatory functions of the forests contributes to a stable functioning of catchment basins of the rivers ensuring lake sustainability in general as an integrated ecosystem within the Lake Baikal drainage basin. It is pointed out that the secular dynamics of forests associated with the succession of forest-forming species (which is typical for the zonal types of vegetation) under climate change promotes the formation of polydominant dark-light-coniferous and light-coniferous forests, also influences the hydrologic regimes of rivers in the study areas. We identified the structural-dynamic organization of forest communities under different physical-geographical conditions and the characteristics of their formation, which made it possible to forecast the vector of possible development of forests within the Lake Baikal drainage basin. It is shown that changes in the structure and dynamics as well as in the spatial organization of forests within the lake’s drainage basin as a consequence of an intensification of fires over the last several decades and recent industrial harvesting affect the river discharge and, as a result, the relatively abrupt water level fluctuations in the lake from year to year. It is established that the trends in forest formation within the basins of the rivers flowing into Baikal are responsible for the relationships in the “forest structure-period of flooding of rivers”, which will influence optimization of forest use within the Lake Baikal drainage basin as a whole.
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