Home – Home – Jornals – Contemporary Problems of Ecology 2010 number 2

The photosynthetic capacity of wood plants under urban conditions was evaluated on the basis of the level of reduced assimilates. Noticeable deceleration of the synthesis of carbohydrates was observed in Sorbus sibirica and Tilia cordata during vegetation, which correlated negatively with the overall technogenic load on the atmosphere in different districts of the city. It was concluded that this index of photosynthetic capacity may be used as an indicator of overall pollution of urban air, and Tilia cordata may be accepted as the indicator species.

Possibility to describe the regularities of the radial growth of wood plants and their properties using the deformation model is demonstrated. Examples of such a description for the subarctic and temperate zones in the perennial and annual climatic cycles are given.

A system of integrated multiрarametric descriрtion of landscapes of micro- and meso-hierarchic levels is developed. On the basis of field descriptions made according to this system in the Chuya steppe, a geographical database was compiled; it contains qualitative and quantitative characteristics of the land-based ecosystems of the Chuya steppe and their major components (relief, rocks, soil, vegetation). The technology for automated calculation of the ratio of abiotic to biotic components of micro-landscape on the basis of digital photographs of the reference grounds was tested. Using the triangular diagrams, the component composition of meso-landscapes was analyzed. The results may be used to decipher and interpret the data of remote probing sensing of the Earth, and also for mapping and modeling geosystems at the local and regionаl levels.

Data on the impact of ground fire events on forest ecosystems in the Eastern Pribaikalia are anаlyzed. The negative impact of ground fires on the growth and productivity of tree stands is demonstrated. The characteristics of lower vegetation layers are presented, variations of soil parameters under the impact of fire events of different intensity and remoteness are demonstrated.

Results of the investigation of the parameters of post-fire succession and seed-bearing capacity of modal tree stands, factors of ground environment (thickness of the unburnt layer of forest litter, projective cover of grass and mossy vegetation), as well as the number, vitality and age structure of self-sown Pinus sylvestris and accompanying small-leaved species in the Lower Selenga pinery of forest-steppe in the south-west of Transbaikalia are presented. The seed crops turned out to be 1,5-2 times more abundant in comparison with the geographically substituting forest types in the forest-steppe of West Siberia, while the vitality of pine undergrowth under the canopy of tree stands passed by fire was extremely low. It was demonstrated that pine reforestation is successful at fire sites in the zone of semination from the forest walls and in the fire sites with sparse growth of trees in bilberry-rhododendron pineries: 2-3 times more abundant than that in the forest-steppe of West Siberia, and insufficient at fire-sites in bearberry-lichen pineries.

The studies were conducted in different parts of the Baikal Region - Southern Prebaikalia, South-Western Transbaikalia, and Northern Prebaikalia. It was shown that the biogeographical conditions have a greater effect on alteration of the trends of chemical elements concentrations, while they exhibit smaller changes in different forest types in the same geographical region. However, the most significant factor causing misbalance of the majority of elements is the emission load. It is concluded that the investigation of the trends of elements contents in assimilating organs of trees serves as the most important link in the system anаlysis of the vital state of tree stands under natural conditions and under the action of abiotic factors.

Ecological conditions in solifluction areas that are widespread in the cryolitic zone of Central Evenkia are investigated. Essential changes of microhabitat in some solifluction "microecosystems" are recorded. They are sharply different from microhabitat in the reference stand. These new ecological conditions result in changes of plant species composition and its diversity. However, no essential differences among ecological groups with respect to hydrothermal and trophic conditions were revealed.

Reservoir construction on large rivers drastically changes the environment of flood-plain. Plant succession and rapid change of plant species start in the flooded zone. The results of investigation of succession processes in the plant cover arising in the area of flooded native ecosystems under the impact of the Sayan-Shushenskoye reservoir are presented.

The state of trees in five types of virgin spruce forest at the territory of the Pechoro-Ilych biospheric reserve was investigated. It was revealed that mature stands of bilberry and fern wood sorrel spruce forest types are characterized on the basis of the vital state of trees as the "healthy forest stand" with the damage index 0,03 to 0,50. The tree stand of polytric spruce forest with the damage index 0,7 relates to the category of "weakened tree stand". Reforestation process is expressed in all the types. The undergrowth accounting for 1,5 to 4,3 thousand sp. ha^-1 consists mainly of conifers and is healthy.

Seven groups of conjugated vascular plants were marked out in the vegetation of landscapes in the upper and middle stream of the Pechora river basin using the Brave conjugate coefficient and graph theory. It was also revealed using Ellenberg indicator values and Ipatov coefficient that the assemblies of the investigated species occupy different positions in the ecological space and are characterized by clearly exhibited coenotic role in quite definite plant communities. The pleiades  of conjugated species, the majority of which was interpreted as ecological-coenotic groups of species, may be used as the indicators of eco- and biotope conditions.

Effect of strong (75 %) and complete (100 %) artificial defoliation of Betula pendula Roth on the dynamics of soluble sugars and phenols - flavonols, catechins and tannins - in the leaves of damaged plants was investigated. Within the first 15 days after strong defoliation of birch, no changes in flavonol, catechin and tannin content were revealed in the leaves. The amount of sugars increased at first, but returned to the normal level on the 10th day after defoliation. One year after strong defoliation, the amount of catechins and tannins in the leaves of damaged trees increased, while the amount of flavonols and sugars did not exhibit any differences from the leaves of reference trees. Within two years after strong damage, increased tannin content is conserved in the leaves, while the level of catechins and sugars remains at the reference level. One year after complete (100 %) artificial defoliation, the amount of flavonols and sugars in the leaves of damaged plants did not differ from that in the reference plants, while the concentrations of catechins and tannins exceeded those in reference plants. Two years after complete damage, the leaves contained increased amount of tannins, while the level of catechins, flavоnols and sugars did not differ from the reference.

The species composition of the lichen flora of steppe communities was determined for the first time on the basis of own collections made in the State natural reserve "Khakasskiy". It consists of 134 species, 47 genera and 27 families. Biomorphological, ecological and geographical analyses were carried out.

Based on detailed analysis of the stratigraphy of a standard peaty profile laid on the large oligotrophic bog in the country between the rivers Kas and Sym, the left bank tributaries of the Yenisei river, the change of local vegetation and hydrological regime in the course of past seven thousand years was reconstructed.
Analysis of the stratigraphy of peat deposit revealed three stages of local changes of bog vegetation. Different degrees of bog moisture correspond to these stages. It was established that the regional climate had only a slight effect on the development of bog ecosystem.
The process of peat accumulation and its rate greatly varied during different periods of the Holocene. The average rate of peat accumulation in the profile was 0,88 mm/year.

A model of phylogenetic development of the vital forms of herbaceous plants is proposed on the basis of multiaspect studies of physiological and morphological indices of the complete species compositions of two herbaceous coenoses (meadow and steppe). It is stated and justified that the physiological mechanism of their development, as water supply of the environment changes, consists in optimization of water deficit and production capacities of the leaf, respective emergence of the most economical species-related sprout forms (non-rosette, semi-rosette and rosette) and finally in the establishment of a definite proportion between these forms within the composition of this or that herbaceous coenosis.

The seasonal dynаmics of water-soluble substances and water content in the meristematic tissues of vegetative buds of Picea obovata L. and Pinus sуlvestris L. are considered. Changes of the concentrations of cytoplasmic solutions of meristematic cells under their dehydration as a result of extracellular or extra-organ ice formation were determined. It was discovered that the concentration of water-soluble substances of the cytoplasm can increase by a factor of 2-2.5 with a decrease in temperature in the negative range down to -40 °С as a result of water crystallization. A connection between the cellular content of water able to get crystallized, unfreezing water and the concentration of water-soluble substances under temperature decrease from 0 to -40 °C was established.

Structural and functional features at the level of the leaf apparatus, sprout, entire organism of Syringa vulgaris under the conditions of Kemerovo city were revealed. The possibility to use these features in the diagnostics of atmospheric pollution was evaluated.
Maximal changes of the parameters under investigation for Syringa vulgaris were observed in Zavodsky, Kirovsky and Rudnichny districts that are characterized by the high degree of atmospheric air pollution.

It was established on the basis of the data of perennial observations that the annual growth of the layer of early tracheids of the trunk and the skeletal root of pine correlated with each other (r = 0,72-0,73). The size of annual rings of the organs under investigation were determined mainly by the width of the layer of early tracheids (r² = 83-92 %) and were dependent on their radial diameter by 50 % for trunk and by less than 20 % for the skeletal root. The width of the layer of early and late tracheids of the trunk and skeletal root was significantly correlating with warmth and water supply, while the radial diameter of early and later tracheids was determined mainly by the temperature conditions of the environment. The joint effect of temperature of air and soil, air humidity and precipitation on the structure of annual rings of trunk and skeletal root, excluding the width of the layer of late tracheids, was 34-58 %.