Spatial distribution of coarse woody debris in pine forests of the Marii El Transvolga region

The spatial distribution of coarse woody debris in pine forests has been studied in the Transvolga region of the Marii El Republic. For this purpose, 30 test plots have been established in pine (Pinus sylvestris) stands of the study region. The results are indicative of a tendency toward the spatial grouping (clustering) of woody debris by fractions, decomposition classes, and stocks along with increase in stand age.     

Variations in the annual increment and net production of Hylocomium splendens in the southern taiga forests of Krasnoyarsk krai

The dynamics of annual increments in the glittering wood-moss Hylocomium splendens (Hedw.) Schimp. in B.S.G. has been studied in different forest types (Kezhemskii district, Krasnoyarsk krai). The linear increment and phytomass of mosses have been measured over 7 years. The density of moss mats has been determined, and parameters of annual aboveground production under different growing conditions have been compared.     

Dynamics of carbon balance components in fallow arable lands on the Valdai Upland

The dynamics of carbon pools in the live phytomass, necromass, and soil reservoirs have been analyzed in fallow arable lands of Novgorod oblast. The results show that the amounts of above- and belowground necromass increase with the age of fallows, while the dynamics of live phytomass have no distinct trend. Comparisons with archival data show that the stocks of soil organic carbon in the studied ecosystems have decreased by 1.39 t C/ha since 1983, which is equivalent to an annual loss of 0.03 t C/ha. The main factors accounting for changes in the carbon stocks of fallow soils are the initial organic carbon contents in topsoil, the intensity of agromeliorative measures taken during the period of agricultural land use, and carbon contents in soils of meadow communities typical for a given region (zone).     

Organic carbon fluxes in the system soil-phytocenosis of bilberry-sphagnum spruce forest in the middle taiga zone of the Komi republic

Quantitative characteristics of organic carbon stock and distribution in the main ecosystem blocks and production-destruction processes in the soil-phytocenosis system have been evaluated in wet oldgrowth bilberry-sphagnum forest. It has been shown that equivalent amounts of carbon are accumulated in the soil and plant reservoirs of the ecosystem and that atmospheric carbon fixation for phytomass production prevails over carbon release in the course of necromass decomposition.     

Carbon dioxide exchange in the photosynthetic apparatus of trees in a mature spruce phytocenosis of the northern taiga subzone

Carbon dioxide exchange was studied in the photosynthetic apparatus of Siberian spruce (Picea obovata Ledeb.), Siberian larch (Larix sibirica Ledeb.), and weeping birch (Betula pendula Roth.) in a mature spruce forest. Parameters of CO₂ balance in different weather were characterized quantitatively on the basis of daily measurements of CO₂ exchange in needles and leaves of woody plants. The percent ratios of the components of carbon balance in needles and leaves of woody plants depending on daily photosynthetic fixation of carbon were determined. In summer, trees consumed 210 kg CO₂/ha (57 kg C/ha) in variable weather and 117 kg CO₂/ha (32 kg C/ha) in cloudy weather. Species specificity of CO₂ consumption was revealed, and the effects of environmental factors on the assimilatory activity of trees were determined.     

Influence of spruce and pine on the acidity and composition of atmospheric fallout in north taiga forests of an industrially developed region

The ideas concerning the spatial and temporal variation of acidity and composition of atmospheric fallout in forests of the boreal zone are discussed. The role played by the atmospheric component in the functioning of these forests depends on the acidity and composition of fallout and the extent of their transformation by the biocenosis. The most profound transformation of fallout occurs during the growing season. In spaces between crowns, the corresponding changes are atmogenic; in undercrown areas, they are obviously biogenic (autogenic). Spruce transforms the fallout more intensively than pine. Under conditions of industrial pollution, the atmobiogenic character of fallout is supplemented with a technogenic component, as its acidity and concentration of pollutants and other elements sharply increase. Concentrations of principal cations reach high values because of their leaching from the crown by acid precipitation. The traditional concept of atmospheric load on boreal forests should be reconsidered taking into account their spatial structure.     

Drivers of broadleaved evergreen species spread into deciduous forests in the southern Swiss Alps

Regional Environmental Change - The spread of non-native species into natural communities is a noticeable phenomenon linked to global change. Drivers of such invasions, however, may differ...     

Effect of emissions from petroleum gas flares on the reproductive state of pine stands in the northern taiga subzone

Characteristics of the adaptive response of the female generative system of Scotch pine to air pollution caused by petroleum gas burning in flares during oil production in Western Siberia have been studied. The relationship between the individual and endogenous variations of the quantitative parameters of pine cone morphology has been analyzed in different zones of deterioration.     

Biological productivity of bogs in the middle taiga subzone of Western Siberia

New experimental data on biological productivity of plant communities in oligotrophic and mesotrophic bogs of the middle taiga subzone over the past five years are presented. The relationship between net primary production and the stock of live phytomass is estimated. The stock of necromass in oligotrophic bog ecosystems increases from west to east, while the stock of live phytomass and net primary production decrease.     

Spatial population structure in forest voles of the genus <Emphasis Type="Italic">Clethrionomys</Emphasis> in the southern taiga of the Middle Irtysh region

A comparative analysis of spatial population structure in the northern red-backed vole (Clethrionomys rutilus Pall.) and large-toothed red-backed vole (Cl. rufocanus Sund.) has been performed in the middle taiga zone of the Middle Irtysh region (Omsk oblast). Populations of these species are represented by sets of territorial groups whose numbers and spatial distribution change from year to year depending on the ratio of these species in a biotope and their population density. There is no significant interspecific competition between cohabitant Cl. rutilus and Cl. rufocanus. In particular, this follows from the fact that the population density and distribution pattern of one species are independent of those of the other species. It has been found that the size of home ranges in Cl. rutilus inversely depends on its population density, with that in Cl. rufocanus remaining approximately the same at different population densities, and that the structure of the resident part of the population in both species changes during the season, as voles from neighboring habitats or dispersing voles settle in the study area.     

Experience in establishing a natural standard for analyzing the dynamics of taiga ecosystems

Experience in organizing a natural reference area (standard) for studies on the functional dynamics of ecosystems in connection with paludification and forest-bog relationships is described. The essence of studies on ecosystem dynamics with the aid of natural standards and key plots is described using an example of the Yenisei region of Western Siberia. Arguments are presented for the necessity of using a differential approach to studies on the dynamics of nature and taking into account local ecological conditions while extrapolating the results of these studies to other geographic regions.     

Ecological structure of plant communities on spring fens in the mountain taiga belt of the Southern Urals

Based on gradient analysis and indicator values, spring water chemistry and temperature and the dynamics of water level were shown to be the main ecological factors of plant cover differentiation in spring fens. Six groups of plant communities were identified by ordination along the axes of these factors, with each group being characterized by a certain suite of indicator species.     

Resuspension of coarse fuel hot particles in the Chernobyl area

Measurements of resuspended aerosol in the Chernobyl 30-km exclusion zone have shown coarse fuel hot particles in the activity range 1-12 Bq 137Cs per particle. The particles were sampled with newly designed rotating arm impactors which simultaneously collect during the same experiment three samples with fuel particles in the size ranges larger than 3 microns, larger than 6 microns and larger than 9 microns in geometric diameter. The radionuclide ratios, determined after gamma-spectrometry, were in good agreement with the theoretical calculations for the radionuclide-composition of the Chernobyl Nuclear Power Plant at the moment of the accident and the measured hot particles in soil in the early years after the accident. The number concentrations of airborne hot particles were derived from digital autoradiography. For wind resuspension, maximal concentrations of 2.6 coarse hot particles per 1000 m3 and during agricultural activities 36 coarse hot particles per 1000 m3 were measured. The geometric diameter of single hot particles was estimated to be between 6 and 12 microns.     

Impact of vegetation types on the floristic diversity,the availability and the ecological characteristics of five woody species stands used in the management of hypertension and diabetes in southern Burkina Faso

Environment, Development and Sustainability - The use of modern drugs to manage hypertension and diabetes is enough expensive and requires constant monitoring of the patient due to the chronicity...     

Biological turnover of chemical elements in a secondary deciduous-coniferous forest of the middle taiga subzone

The biological turnover of nitrogen and ash elements has been studied in a secondary deciduous-coniferous stand formed in place of a clear-cut spruce forest. The results have shown that a high degree of accumulation is characteristic of Ca, N, K, and Si, with N, Ca, K, Si, P, and Mg being most actively involved in the biological turnover. The biological turnover in this stand is of the calcium-nitrogen-potassium type, and its intensity and rate exceed those in bilberry spruce forest by factors of 1.7 and 2–4, respectively.     

The radiological impact of the Chernobyl debris compared with that from nuclear weapons fallout

Our basic knowledge of the radiological impact of fallout from nuclear accidents is based on the experience gained from the study of nuclear weapons fallout. Radioecologically, the most important radionuclides generated by the Chernobyl accident were ¹³⁷Cs, ¹³⁴Cs, ¹³¹I and, to a lesser degree, ⁹⁰Sr. These nuclides are well known from global fallout, although in different relative amounts to those observed in the Chernobyl debris. Another important difference between the fallout from Chernobyl and that from nuclear weapon tests is that their seasonal and geographical distributions were quite dissimilar. A number of examples show how these differences influenced transfer factors and thus population doses. Special emphasis is paid to the contamination of milk and cereal products.Furthermore, it is shown how the composition of the Chernobyl debris changed with distance from Chernobyl, due to the differences in volatility of the various radionuclides involved. Finally, the paper compares the dose equivalents received from unit releases (1 P Bq ¹³⁷Cs) of global fallout and of Chernobyl accident debris.     

The Holocene Evolution of Vegetation in the Southeast of the Volga Upland

The Holocene evolution of vegetation in the high-plain territory of the northwestern Volga Upland has been shown to have certain specific features. Based on analysis of spore–pollen assemblages from peat deposits, the onset of bog formation has been dated to the late Boreal period (about 8500 yr BP); the pine–birch phase in the development of forests, to the early Atlantic period (8000?6000 yr BP); the appearance and peak development of the zonal broadleaf species complex, to the late Atlantic period (6000?4500 yr BP); and early anthropogenic changes in the vegetation, to about 3000 yr BP.     

Assessment of surface waters acidification as indicated by zooplankton in the taiga zone of Northern European Russia

Published results of comprehensive hydrochemical and hydrobiological studies of water bodies in the taiga zone of northwestern Russia were analyzed to estimate the lowest values of water pH at which individual zooplankton species had been recorded. On this basis, the most significant species indicative of surface water acidification were identified and a scale of their distribution depending on the degree of acidification was compiled.