Changes of Structural and Physicochemical Parameters of Spruce Forest Ecosystem under the Effect of Moose (Alces alces L.)

The role of moose in the dynamics of structural, physical, and chemical parameters of a forest community is considered using an example of a southern taiga wood-sorrel spruce forest. It is shown that the activities of these animals affect the vertical structure of the underbrush and understory layers, the dynamics of phytomass accumulation, and the state of the ground vegetation. Changes in the nitrogen and hydrocarbon flows through the ecosystem under the effects of moose activities are analyzed.     

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.     

Response of the Avifauna to Technogenic Environmental Pollution in the Southern Taiga Zone of the Middle Urals

The results of original studies and published data are used for evaluating the main responses of the avifauna of boreal forests to the combined effect of sulfur dioxide and heavy metals. It is shown that environmental pollution results in the reduction of species richness, biomass, and stability of the nesting bird fauna. In degraded areas, the structure of the bird community changes: (1) typical forest species are replaced by the species of open habitats, and (2) the proportion of species nesting in the upper tree layer decreases, whereas that of ground-nesting species increases.     

Analysis of Factors Determining Accumulation of 137Cs by Woody Plants

The accumulation of ¹³⁷Cs by coniferous (Pinus sylvestris) and deciduous (Betula pendula) trees was studied in the area contaminated with radioactive products after the Chernobyl accident. The availability of ¹³⁷Cs to woody plants is determined by its vertical distribution in the soil profile, the proportion of its exchangeable form, and the distribution of tree roots in the soil. The index of biological availability of ¹³⁷C in the soil is proposed, and its linear dependence on the coefficients of ¹³⁷Cs transfer to wood is demonstrated.     

Effect of Solidago canadensis on the Species Diversity of Phytocenoses in Belarusian Polesye

Russian Journal of Ecology -     

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.     

Urban Flora as a Component of the Urban Ecosystems in the Taiga Zone: An Example of Karelian Cities

Cities are areas of increased diversity of species in the taiga zone. The aboriginal fraction of Karelian flora is a stable natural system whose main characteristics are preserved in the urban flora. The adventive fraction, which is a dynamic component of the flora, has not been completely formed in the cities, as well as in eastern Fennoscandia as a whole. It has become substantially richer during the past 20–25 years. Cities of the taiga zone may serve as objects for monitoring the anthropogenic processes of flora transformation in the North.     

Characteristics of Cajander Larch (<Emphasis Type="Italic">Larix cajanderi</Emphasis> Mayr) on Dredging Waste Dumps in the Amur Region

Former dredging sites were studied in the taiga zone of the Amur region (in Khabarovsk Krai). The involvement of Larix cajanderi in plant succession on dredging waste dumps was revealed. Some morphological-anatomical parameters of L. cajanderi needles were compared in trees growing on the dumps and in adjacent open larch stands on waterlogged peaty soils.__________Translated from Ekologiya, No. 4, 2005, pp. 259–263.Original Russian Text Copyright © 2005 by Osipov, Burundukova.     

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.     

Chemical pollution: Transfer of chemical elements to the aboverground phytomass of herbaceous plants

Changes in the species composition and a decrease in species diversity and total plant biomass along the gradient of soil pollution with heavy metals have been shown. Data on the concentrations of chemical elements (Zn, Cu, Cd, Pb, Co, Ni, Mn, Cr, and Fe) in the aboveground organs of herbaceous plants and the biomass of each species make it possible to estimate the role of higher producers in the incorporation of chemical elements into biogenic cycles in background zones and under conditions of chemical pollution. Plants of the composite family (Asteraceae) play the main role in accumulation of chemical elements. The results obtained indicate that natural ecosystems have mechanisms limiting excessive accumulation of chemical elements into the aboveground plant biomass.     

Plant communities in the zone of gas field development and heavy metal accumulation by them

Heavy metal accumulation by plant communities has been studied in different zones of impact of gas field development. The contents of heavy metals in different blocks of plant communities has proved to depend not only on the location of phytocenosis but also on its species composition. Communities dominated by species of the family Poaceae contain smaller amounts of heavy metals than those dominated by species of the family Asteraceae, especially of the genus Artemisia. The order of precedence in the accumulation of heavy metals in different blocks of plant communities has been revealed.     

Trends in the formation of biotopic complexes of bumblebees (Hymenoptera, Apidae: Bombini) in northern taiga karst landscapes of the Western Russian Plain

Main trends in the formation of biotopic complexes of bumblebees in the northern taiga zone are analyzed. It is proposed that Eurasian forest species of bumblebees (Bombus (Th.) schrencki, B. (Mg.) consobrinus, etc.) are coadaptively connected with entomophilous plant species belonging to the synusia of Eurosiberian riverine-mountain meadow tall herbage, with the numbers of species in both biotic groups (pollinating insects and plants) and their abundance being greater in the landscape characterized by a high degree of karstification. In the biotopic bumblebee complex of a large river valley, the relative abundance of forest bumblebee species is 2.5–5.3 times lower than in other complexes, whereas that of meadow species is two orders of magnitude higher due to favorable thermal conditions and a large number of habitats with mesophilic herbage and legumes. Each of the distinct ecogeographic groups of bumblebees and the corresponding synusiae (each comprising entomophilous plants of different taxonomic groups) appear to be coadapted. This is probably a result of the diffuse coevolution of pollinators and plants belonging to the genetically unified biota.     

Carbon Concentrations and Caloric Value of Organic Matter in Northern Forest Ecosystems

Russian Journal of Ecology -     

Phenes of Woody Plants: Identification,Scaling, and Use in Population Studies (An Example of Pinus sylvestrisL.)

The methods of identification and scaling of phenes of forest plants are described. The phene identification consists of five stages. Specific features of studies at each stage are shown using identification of the phenes of seed color, cone color, and seed scale structure in Scotch pine (Pinus sylvestrisL.) as examples. The method of phene scaling is based on the comparison of phene frequencies in a bog and in adjacent upland populations of pine. At the boundary between the bog and dry land, the frequencies of population-level phenes change, whereas those of superpopulation-level phenes remain unchanged.     

Biodiversity of plants and soils in landscapes adjacent to the Buzuluk Pine Forest

The influence of the Buzuluk Pine Forest on biodiversity of plants and soil properties in adjacent territories has been studied. The results show that in the immediate vicinity of the pine forest, under the influence of the relatively mild and humid mesoclimate, natural phytocenoses are dominated by mesophytic species. Biodiversity reaches a peak at a distance of 17–18 km from the forest, which is explained by the presence of both mesophytes and xerophytes in the same phytocenosis. The same zone is also characterized by the maximum diversity of soil properties and structural complexity of the soil cover. Grass communities on ordinary chernozems with a homogeneous soil cover, typical of the steppe zone, are formed at greater distances from the forest.     

Accumulation of metals by vegetation in a small drainage area exposed to aerotechnogenic pollution

Trends in the accumulation of metals by different plant species have been analyzed in a forest phytocenosis of the southern taiga zone of the Middle Urals, which is polluted by emissions from a copper-smelting plant. The rate of metal accumulation in the course of annual and net phytomass production and metal outflow with surface waters beyond the biogeocenosis boundaries have been estimated.Translated from Ekologiya, No. 1, 2005, pp. 26–31.Original Russian Text Copyright © 2005 by Fedorova, Odintseva.     

Mortality and recruitment of mountain birch (<Emphasis Type="Italic">Betula pubescens</Emphasis> ssp. <Emphasis Type="Italic">czerepanovii</Emphasis>) in the impact zone of a copper-nickel smelter in the period of significant reduction of emissions: The results of 15-year monitoring

Long-term monitoring of mountain birch populations (1992–2006) was performed in 14 test plots located at distances of 1 to 63 km from the copper-nickel smelter in Monchegorsk (Murmansk oblast) and differing in the degree of disturbance. In the period from 1999 to 2006, atmospheric emissions of sulfur dioxide and heavy metals amounted to only one-third of those between 1992 and 1998, but birch mortality in heavily polluted areas (with nickel concentrations in leaves exceeding 160 mg/kg) remained at the same level, being absent (as previously) in less polluted areas. Throughout the observation period, birch recruitment was observed only in areas where nickel concentrations in the leaves were below 160 mg/kg; i.e., this concentration proved to be the threshold with respect to both mortality and recruitment of mountain birch. The course of demographic processes in its populations has remained unchanged after the reduction of emissions, confirming the hypothesis of the “inertial“ effect of industrial emissions on ecosystems. In some areas of industrial barrens, mountain birch may perish completely within the next decade.     

Carbon cycle in spruce ecosystems of the northern Taiga subzone

The main components of the carbon balance have been determined in old spruce-bilberry forests of the northern taiga subzone. Annual carbon deposition in live phytomass and necromass has been determined by the weight method. Photosynthetic carbon binding has been calculated using the chlorophyll index, and the daily carbon balance has been estimated on the basis of direct measurements of CO₂ exchange. The results have shown that photosynthetic carbon binding by the phytocenosis amounts to 3.5–4 t/ha per year. Taking into consideration the litter yearly deposition decreased up to 1 t C/ha per year. With more than 70% of carbon accumulated in the organic mass being oxidized within the phytocenosis and returned to the atmosphere in the form of CO₂. Spruce ecosystems serve as a sink for 0.2–0.3 t C/ha per year.     

Ecophysiological indicators of the state of animal populations exposed to damaging factors

Indices of abundance and reproduction rate are considered in some groups of aquatic and terrestrial vertebrates from the zones of technogenic disasters. Upon a critical population decline caused by external destructive factors, such as emissions of acute ecotoxicants, the ecophysiological and behavioral compensatory mechanisms are activated, which provide for restoration of the total population size to the optimum within a short period of time. Environmental pollution with substances disturbing the reproductive function has the gravest consequences for animals. In this case, population size may remain fairly high, and, therefore, the effect of enhanced reproduction as a response to population decline does not take place, which eventually leads to a gradual but irreversible destruction of the population. Pathologies of reproduction should be used as a criterion for assessing the state of animals in the zones of technogenic disasters.Translated from Ekologiya, No. 1, 2005, pp. 32–38.Original Russian Text Copyright © 2005 by Shilova, Shatunovskii.