Home – Home – Jornals – Contemporary Problems of Ecology 2009 number 5

It was revealed that a sharp increase in the top phytomass occurs in the groupings, formed at the pit walls, at the first stage: during active colonization of open territories by plants. At subsequent stages, an increase in the phytomass slows down, only the relations between the botanic groups comprising the phytomass changes substantially. In phytocenoses developing on dumps, an increase in the phytomass proceeds gradually at all the stages.

Features of the spontaneous succession in a broad-leaved forest landscape (Polessye province, Belarus) are considered. The regularities of changes of the vegetation (specific structure, vital forms, phytocoenotic structure) and the characteristics of ecotope (on the basis of phytoindicator scales) over the succession gradient were revealed. It was established that the most essential changes of microclimate and soil occur at the stage of formation of the wood ecosystem.

Influence of reservation rate on natural degraded pasture areas at different stages of pasture digression was studied during the years 1994-2004 under the conditions of the right-bank forest-steppe near the Ob river. It was revealed that the isolation of pasture phytocoenoses of a steppe meadow from pasturing causes an increase in the productivity of grass but due to different economic-botanical groups of plants. An increase in the productivity at the initial stage of digression occurs due to overgrowth of legumes and motley grass, while at the final stages mainly due to an increase in the mass of cereals. Removal of pasture load promotes the formation of intermediate communities; in this situation, an increase in their species diversity is to a high extent due to the presence of closely located phytocenoses which are richer from the floristic viewpoint.

Correlations between the structure of phytocenoses representing different stages of the process of forest formation in the Polar Urals mountains and moistening of ecotopes, as well as between the lower layers and forest stand are considered. Current density of trees and undergrowth is not exhaustive of the ecotope capacity, and therefore open woodland can be transformed into closed forest. Perspectives of such a transformation within a certain plot may be assessed by percentage of mesophilic and relatively thermophilous (hypoarctic + boreal) species in the herb-dwarf shrub layer.

The experience of growing field-protective forest belts of different species composition under arid conditions of the Shira steppe of Khakasia is considered. The results of the investigation of species variety, distribution of grass plants over ecological groups, and revelation of the regularities of species composition dynamics, structure and biomass of living grass cover in field-protective forest plantations are reported. The question concerning the influence of development stage of the living grass cover on the forest belts growth is considered.

Specific role of climatic, geographic, lithologic, hydrochemical etc. conditions of soil formation in the differentiation of the soil cover in the Turan-Uyuk depression in Tuva is considered.

Current state of woodland belts in the Altai Territory is anаlyzed; forestry activities aimed at the protection of the existing forests and planting the new ones to improve the ecological situation in steppe Kulunda are planned.

Investigations of the climatic parameters and protective characteristics of forest ecosystems were carried out at a small drainаge area in the upper reach of the Ussuri river (Southern Sikhote Alin') as an example. Anаlysis of the 40 years dynamics of air temperature and the regime of atmospheric precipitation showed that changes of the temperature background and preciрitation redistribution within a year occur: a trend to an increase in the average annual air temperature is observed as a result of warming during the cold and transition periods of a year, the number of years with insufficient wetting during the summer and autumn seasons and with snowy winters increases. The ecological potential of the basin, expressed in the quantitative indices of water-regulative and water protection role of parent forests, is decreased after the experimental felling of main use. With the general increasing negative dynamics of the forest resources of the region, climatic changes may cause an increase in the surface drainage during spring, a decrease in the channel runoff, worsening of watering and water quality of large river basins.

Rare plant species of Central Siberia, included in the regionаl Red Books, are considered from the positions of their population strategies. The analysis of potential possibilities and positions of species populations is given. The functionаl approach to the evaluation of rare plants behavior is proposed.
The functionаl typology of rare plants and specific features of their behavior is recommended to be used for the development of protection modes for rare plants.

Results of the comparative anаlysis of the state of larch plantations in the regions of Krasnoyarsk differing in the levels of air pollution are presented. The features of the structure of crown and the correlation structure of habitus signs and tree states observed in the regions with medium and high level of air pollution are shown. It is concluded that the sensitivity of correlation signs is higher and they are suitable to reveal changes that cannot be diagnosed with the help of the eye survey of tree state.

On the basis of investigation of the features of pollen of 16 coenopopulations of Potentilla bifurca in five provinces of the Altay-Sayan mountain region, two groups of coenopopulations were revealed: western and eastern. Both groups are characterized by the high intrapopulation (44,7-63,9 %) and lower interpopulation (11,4-42,2 %) variability. The observed similarity between the groups of coenopopulations of P. bifurca from different geobotanical provinces is determined by their common origin in the steppe communities of Pliocene-Pleistocene.

Peculiarities of the distribution Coniogramme intermedia within the Russian Far East are marked. The characteristics of location, species diversity and structure of plant groupings in the inhabited placed are presented. Some measures to preserve endangered communities of coniferous and broad leaf forests with the particiрation of Coniogramme intermedia are proposed.

Seasonаl dynamics of Anаbaena flos-aquae (Lyngb.) Breb., including vegetative cells, akinetes and akinete envelopes in bottom sediments and water column in a small Siberian reservoir was studied. It was assumed that even in a rather shallow mixed water reservoir, water bloom with cyanobacteriae starts in the littoral zone and then spreads over the whole water reservoir. Two types of akinetes were observed: in the first half of summer Anаbaenа formed akinetes, which served for vegetative reproduction and germinated in water column soon after differentiation, while in the second half of summer the akinetes served as resting stages, which were deposited to bottom sediments. It was demonstrated that even in the comparatively shallow unstratified reservoir the summer developments of the A. flos-aquae population started in littoral and no rise of akinetes from the sediments of the deeper central station occurred. Thereby, bottom sediments of the profundal parts of reservoirs seem to be a "cemetery" for akinetes of cyanobacteria, which never will germinаte from these sediments. At littoral and open-water stations, abundance and seasonal dynаmics of akinetes in water column and their sinking pattern were very similar. However, seasonаl dynаmics of the abundance of akinetes in sediments in these two reservoir locations differed: whereas the abundance of akinetes in open water increased permanently during the summer, that in the littoral decreased soon after their sedimentation. During winter, the abundance of akinetes in bottom sediments tended to decrease. The reasons of this phenomenon are unknown yet.

The living plankton diatom - Asterionella formosa of Lake Baikal and of the Irkutsk reservoir was studied with the use of light microscopy. The new facts were obtained which provide evidence of the occurrence of multiрle asexual reproduction of Asterionella formosa.

Distribution of phytoecdysteroids in the Caryophyllaceae family is anаlyzed; the largest number of ecdysteroid-containing species was discovered in this family. The species of this family synthesize the wide variety of steroid compounds - the hormones of moult and metamorphosis of insects, many of which are not detected in other plants. The major part of the species of the Caryophyllaceae is characterized by the high levels of phytoecdysteroids. The flowers of the perrenial Silene frivaldszkyanа accumulate up to 7 % of 20-hydroxyecdysone.

Accumulation of phytoecdysteroids in the agropopulations of R. carthamoides (Willd.) Iljin and S. coronata L., as well as their resistivity to phytophagans over the age periods of ontogenesis were investigated for 16 years. As a result of the investigations, the species-specific features of the accumulation of ecdysteroids in vegetative and reproductive organs of plants were determined; interrelations between the distribution of phytoecdysteroids in the structure of plants and the ecological relations with insects were revealed; the factors promoting damage were outlined; the damage caused by pests was evaluated.