Home – Home – Jornals – Contemporary Problems of Ecology 2006 number 2

In deep peat soils of forest-swamp ecosystems of West Siberia, the structural, dynamic and function

A modification of  M. D. Korzukhin's three-age model of time course of growth of a plant community is considered within whose framework the influence of illumination (solar radiation) conditions on the appearance of new saplings of the lower storey and  the non-linearity of the influence of death of trees of younger classes are taken into account. Dynamic regimes of the model are determined, and it is shown that at certain values of parameters, periodic oscillations, trigger regime (asymptotic stabilization at one of two stable levels depending on the initial values) or stabilization at the only (globally stable) level arise in the model.

Peculiarities of distribution of biomass reserves of the soil cover and underbrush in larch associations of the Central Evenkia depending on ecological conditions and man's influences are considered. It is noted that the reserves of lower storey of forest phytocenoses under the conditions of northern taiga of the Middle Siberia are commensurable with the total phytomass of tree stands. This points to an important role of the vegetation of subordinate storeys in the accumulation of organic substance and to its considerable participation in the circulation of substances in the cryolithozone of Middle Siberia. Fires lead to liquidation of the soil cover , whose biomass restoration here is delayed for many decades.

Methodical aspects of studying the time course of pyrological regimes and their influence on natural ecosystems are considered. The conclusion is made that for elucidation of long-term time course of pyrological regimes it is expedient to unite various sources of data on the history of fires. This makes it possible to eliminate certain drawbacks characteristic of separate methods. The time course of pyrological regimes in the main landscape units of southern taiga of the Yenisei region of Siberia for the last three centuries has been analyzed. A quantitative estimation of deviations of modern pyrological regimes from the past ones has been made. Probable ecological and forestry concerned consequences of changes of the pyrological regimes and possible ways of their control of the pyrogenic factor with the purpose of stabilization of ecosystems are discussed.

The role of climatic characteristics - air temperature, and thunderstorm duration in terms of hours

An approach to isolation of superorganismal systems based in region

The time course of forest resources for the last 40 years is described. The distribution of forests by groups and categories of protection, the resource and species composition, age structure, productivity, protection and reproduction of forests are considered. The positive and negative influences of anthropogenic factors on the changes of the forest resources are noted. Tabulated material on forest resources at the beginning of the century is presented for use in monitoring.

Data on the type of rest of seeds from some species of Alnus Mill. s.l.and on the ways of its overcoming are presented. Specificity of germination of seeds of representative species of various systematic groups of the genus in association with their ecology is shown.

On the basis of L systems, a mathematical model describing the dark coiniferous tree species is created. A software is written which makes it possible to form a computerized tree stand from separate trees and watch its development. For ruling out crossings of branches of growing trees, a rule of prohibition of a shoot growth into an already occupied place is introduced. The model parameters have been determined for two dark coniferous species from the southern Sikhote-Alin - Yeddo spruce and Khingan fir. The model makes it possible to obtain the following effects: variants of change of the form of the tree crown under the influence of neighboring trees, uncertainty of the height of the crown origin, change of rise and form of the trunk depending on the plantation density, renewal of normal tree growth after clearing. A comparison of model results and empirical observations has demonstrated that the model describes well the growth of both single trees and mixed plantations.

Peculiarities of the structure of plant communities formed under the conditions of contact of taiga and steppes of the west bank of the Lake Baikal are discovered in the work. The high contrast of natural conditions of this part of the Baikal region contributes to formation of plant communities varying with respect to species and cenotic composition and forming a transitional zone  between light coniferous forests and steppes that have an extrazon

The time course of total, inorganic, organic and protein forms of sulphur, and the leaf morphostructure of aboriginal species of the genus Salix L. and those introduced to climatic conditions of the Novosibirsk Region were studied under the influence of low doses of SO₂ (0.25 and 1 mg/m³). A correlation between the peculiarities of sulphur metabolism and the change of leaf morphostructure was demonstrated: the higher the background content of protein sulphur and the lower that of total sulphur was, the smaller were the losses of leaf turgor under the conditions of low SO₂ concentration. Introduced Salix L., as compared to aboriginal ones were characterized by a lower background content of total sulphur and a higher content of protein sulphur, which contributes to conservation of leaf turgor and insures a higher resistance of introduced plants to the influence of low SO₂ concentrations.

A simple and efficient method for calculation of the best felling age for tree stands of a certain species is proposed. At the first stage, the method presupposes an approximation of tabulated data on the growth time course with respect to some model equation. At the second stage, the moment of culmination of the average increment of reserves is found analytically, which represents the optimal felling time. The method is illustrated with a calculation of felling times for spruce stands of the Primorye region.

The influence of fungicides on fungi strains of the genus Trichoderma antagonistically active with respect to agents of fusariosis of coniferous trees was studied. Estimation of influence of fungicides TMTD, fundazol and baileton , as well as fungi of the genus Trichoderma , on the growth and development of Pinus silvestris L. seedlings and on their lodging resistance was carried out.

The experience of setting up zoomeliorative tree plantations under arid conditions is considered. Results of studies of pasture-protective forest belts with the Siberian larch at the age of 21 years as the main  species are described. Characteristics of the living soil cover under their canopy after a fire are presented.

The publication aims at attracting attention of Russian scientists to some methodological problems associated with both collection and analysis of the ecological data. By using recent publication by A. G. Kartashev & A. A. Kartasheva (Siberian Ecological Journal, 2004, 1, 25-34) I discuss the typical errors, such as (1) simple pseudoreplication, i. e. statistical conclusions based on evaluation units, not on independent experimental units, (2) multiple comparisons based on intercorrelated characters, including absence of correction for multiple comparisons in large tables of correlation coefficients, (3) absence of information on statistical distribution of the data and, consequently, potential problems associated with calculation of t-statistics and Pearson correlation coefficients for data showing non-normal distribution, (4) replacement of the values of correlation coefficients by their significance. The principal conclusion of the paper - impact of motorways on the structure of webs of the spider Larinioides patagiatus

The temperature regime of chernozems of southern and meadow-chernozem soils of the Ishim steppes characterized by an increased (to the level of the lowest moisture capacity) moisture of subsoil layer  depending little on the ground water level and an absolute dominance of absorbed hardly movable humidity has been studied

The water regime of chernozems of southern chernozems of the Ishim steppe characterized by an increased (to the minimal moisture capacity) humidity of the subsoil layer depending little on the ground water level  and with absolute dominance of absorbed hardly movable humidity in its water phase has been studied.

An estimation of cadmium chloride solution toxicity for two endemic species of Baikal amphipods - Eulimnogammarus verrucosus (Gerstf.) and E. cyaneus (Dyb.) has been carried out. Used as biomarkers of toxic stress at the biochemical level were peroxidase activity criteria and the levels of synthesis of stress protein alpha-crystalline. The results of the study have demonstrated a high degree of toxicity of cadmium chloride for the two species. A decrease of peroxidase activity was found, which probably points to suppression of antioxidation processes in the organism of the crustaceans. On the example of the amphipods in fresh-water crustaceans, the synthesis of the protein alpha-crystalline induced by cadmium chloride was described for the first time. Taking into account that alpha-crystalline is a chaperone, the enhancement of its expression witnesses to probable structural disturbances in cellular proteins.