Abstracts

Forest Ecosystems

The biodiversity management supposes knowledge on trends of change and mechanisms of vegetation’s transformation. The successions observed during XX century, reflect the influence of natural and anthropogenic factors.

The purpose of the present research is the study of particularities on forest vegetation’s transformation of low-mountain subtaiga on the South of the Krasnoyarsk territory. This research attempts to verify the hypothesis about climate-induced fluctuations, which influence on structure and composition of subtaiga belt complex.

The test area occupies the low mountain borderland of East Sayan on the left-bank of Yenisey river near Divnogorsk Hydroelectric Station. It consists of three parts: dark coniferous (fir) taiga, light coniferous subtaiga and transitional subzone.

Dark coniferous taiga is settled on H 450-550 meters. Uneven-aged stands formed by Abies sibirica dominate the belt complex of forest types. On the south slopes the separate old trees of larch and Scotch pine (300 and more years old) occurs.

It was clarified that the transitional subzone (H 350-450 m) between dark coniferous (fir) taiga and light coniferous subtaiga are composed by Scotch pine (dominant of the mature forests), Larch, Aspen and Birch. On the shadowed (northern) slopes Fir in sustainable during last 80-100 years in the second layer of the forest stands.

Scotch pine is sustainable in low-mountain light coniferous subtaiga on H 250 - 350 meters. It have lost sustainability on the south steep slopes below 250 m, where steppe and meadow-steppe bushes and herbs replace pine and birch forest types.

Along with typically subtaiga groups there is a wide range of the other ones (e.g. forest-steppe, steppe, taiga, nemoral bioecogroups). Their combination demonstration mosaic pattern of this ecotone between for steppe and taiga.

Developed on the basis of the test area ordination of forest type series in the system of V.N. Sukachev’s ecological-phytocoenotic ranks revealed forest-typological structure and relations between ECG and soil. It was shown that herb species of forest were dominant. The absence of shrub and mosses forest type series is the specific feature of low-mounted subtaiga and this makes it different from mountain taiga.

Comparing of soil cover and vegetation maps allows to conclude, that the boundary between dark coniferous (fir) taiga and light coniferous (pine and larch) subtaiga zones was not stable in space. There were more humid periods favorable for fir and spruce invasion during last centuries as well as other periods, with increasing role of pine, birch and mixed stands. Wildfires and dryness allowed Pine and Larch population to regenerate. Besides Betula pendula and Populus tremula regeneration was successful in herbaceous forest types, and small – leafed stands have been formed during 70-90 years after cut and crown fires.

The last century is remarked by tendency to fir activity on the low boundary of mountain dark coniferous taiga. The consideration that sustainable positions of Abies sibirica, Pinus sibirica and mixed dark coniferous stands in current climate allows to influence considerably on forest management and to increase -biodiversity in low-mountain subtaiga.

Note. Abstracts are published in author's edition

|Home Page| |English Part|

Go to Home