Cytogenetic Damage of Human Somatic Cells and Weeping Birch Cells in Voronezh Districts with Different Levels of Anthropogenic Pollution

Cytogenetic parameters (the mitotic rate and the frequency of pathological mitoses) of the seed offspring of weeping birch (Betula pendula Roth.) and the frequency of micronuclei in the buccal epithelium of children living in several raions (districts) of the city of Voronezh differing in environmental conditions were studied. Judging from these parameters, the environmental situation was the worst in the Sovetskii raion. A correlation was found between the frequency of pathological mitoses in the roots of birch seedlings and the frequency of micronuclei in the buccal epithelial cells of children. This indicates that the cytogenetic monitoring data obtained in plants may be extrapolated to man.     

Technogenic stress and its effect on deciduous trees (an example from parks in Yaroslavl)

A comparative analysis of several morphological, physiological, and biochemical characteristics of leaves has been performed in birch (Betula pendula Roth), linden (Tilia cordata Mill.), and poplar (Populus nigra L.) trees growing in industrial areas of Yaroslavl with different levels of anthropogenic pollution. The results show that high concentrations of pollutants in the atmosphere suppress the growth of leaves, and the number and severity of necrotic lesions in them increase. Water content in leaves becomes lower, whereas ash content increases. The contents of photosynthetic pigments change as well: the leaves contain smaller amounts of chlorophylls a and b, whereas the accumulation of carotenoids increases. Judging from changes in the test parameters, P. nigra is more resistant to pollution than B. pendula and T. nordata.     

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.     

Species Specificity of the Cytogenetic Stability of Fish in a Eutrophic Water Body

The micronucleus test of peripheral blood erythrocytes was used to study cytogenetic stability in bream (Abramis brama L.), perch (Perca fluviatilis L.), roach (Rutilus rutilus L.), and pike (Esox lucius L.) from a eutrophic water body not affected by anthropogenic factors. The dependence of the rate of spontaneous micronucleus formation on fish age was estimated. The effect of natural variation in abiotic environmental factors on the cytogenetic stability of species was analyzed.     

Accumulation and distribution of90Sr and137Cs in birch in the zone affected by liquid discharge from the Beloyarskaya Nuclear Power Plant

The data are presented that concern the accumulation and distribution of artificial radionuclides (⁹⁰Sr and¹³⁷Cs) in the aboveground organs of birch growing in the vicinity of the Beloyarskaya Nuclear Power Plant (NPP) in the permanently inundated part of the Ol'khovka swamp, on its banks periodically flooded with water, and in watershed areas not influenced by the swamp (control). Concentrations of both radionuclides in birch trees from the swamp and its banks were several times as high as in trees from the watershed. The distribution of⁹⁰Sr in birch trunk proved to be acropetal. Trees growing on the inundated part of the swamp and on dry land significantly differed in the distribution of¹³⁷Cs. The factors controlling the distribution and accumulation of both radionuclides in birch trees growing in these areas are discussed.     

Dynamics of the timberline in high mountain areas of the nether-polar Urals under the influence of current climate change

Changes in the altitudinal position of the timberline in high mountain areas of the Nether-Polar Urals and basic factors that influence such changes have been revealed on the basis of comparison of the age structure of Siberian larch (Larix sibirica) and arctic birch (Betula tortuosa) tree stands and photographs made in different years. On the mountain slopes studied, an upward shift of the timberline took place in areas covered in winter with thick snow (in the late 18th century), with Siberian larch being the pioneer species. Larch began colonizing areas with a thin snow cover in the 20th century. Birch appeared later and has since strengthened its positions. The increase in winter temperatures and precipitation facilitated the expansion of the forest.     

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.     

Changes in the upper limits of tree species distribution in the Western Caucasus (Belaya River basin) related to recent climate warming

To estimate the response of tree vegetation to recent climate warming in the Western Caucasus, the population state of several tree species at the upper limit of their distribution has been estimated in three mountain massifs in the Belaya River basin. For this purpose, the average and maximum stem diameters, vitality, and age of trees have been determined in the transitional zone between middle-mountain and high-mountain beech-fir forests (1400–1700 m a.s.l.) and in crooked birch forests growing at the upper timberline (1810–2025 m). The upper limits of Acer platanoides, A. pseudoplatanus, Ulmus glabra, and Betula litwinowii have shown a tendency to rise. The upper limit of Abies nordmanniana has remained unchanged over the past few decades, which may be explained by a decrease in moisture supply during the warm season.     

Carbon fluxes from coarse woody debris in southern taiga forests of the Valdai Upland

Studies in three typical forest biotopes of the Valdai Upland were performed to evaluate the stocks and surface area of coarse woody debris from spruce and birch (in linear transects), its colonization by xylotrophic fungi (during reconnaissance surveys), and CO₂ emission (by a chamber method). The stock and surface area were minimum in a paludal birch forest (46.4 m³/ha and 960 m²/ha) and maximum in a decay area of spruce forest (256.1 m³/ha and 3761 m²/ha, respectively). The assemblages of wood-decay fungi had a composition typically found in southern taiga forests. The total CO₂ flux varied from 145 kg C-CO₂/ha per year in the paludal birch forest to 462 kg C-CO₂/ha per year in small herb–green moss spruce forest. It is concluded that air temperature is an informative predictor of seasonal C-CO₂ flux rate from coarse woody debris.     

The Holocene Dynamics of Vegetation and Ecological Conditions in the Polar Urals

Palynological, paleocarpological, and paleoentomological analyses of frozen peat deposits near Lake Pereval'noe, the Polar Urals, were performed to reveal the main stages of change in the pattern of vegetation over the period from the beginning of warming after the last Pleistocene glaciation to the late Holocene. Nine to four thousand years ago, the study region (at the present-day upper boundary of open larch forests) was covered with taiga forests, as the climate there was significantly warmer. These were larch–birch forests with an admixture of spruce and, later, spruce forests with larch and birch.     

Size-Dependent Selective Leaf Damage by Insects and Some Methodological Implications of This Phenomenon

The area of leaves on birch (Betula pubescens ssp. tortuosa) auxiblasts and brachyblasts and the degree of their damage by the complex of leaf-gnawing and leaf-mining insects were studied in a light birch forest. The results showed that phyllophagous insects, primarily snout beetles, prefer young leaves on the apexes of auxiblasts. Thus, selective damage is inflicted on smaller leaves, both on the auxiblasts and in the entire sample. This phenomenon is widespread and may manifest itself in different ways, depending on the pattern of leaf area distribution along the extended shoot and the feeding preferences of the insects. Thus, it is necessary to reconsider research methods and approaches based on the assumption that insects damage leaves nonselectively, irrespective of their size.     

Communities of phyllophagous insects in young birch greeneries of northern cities

Phyllophagous insect assemblages on birch trees have been studied in greeneries of the cities of Labytnangi and Salekhard and natural habitats in the environs of these cities in 2007, 2010, and 2013. The 44 recorded species were dominated by insects of the orders Lepidoptera and Hymenoptera (18 and 12 species, respectively); regarding feeding ecology and mode of life, they were dominated by open-living chewing phyllophages and miners (19 and 10 species). The urban greeneries and sparse birch forests were colonized by the same species, but the density of many species in the cities was considerably higher. The species composition of the communities changed considerably from year to year. The species richness and similarity of insect assemblages at the studied sites were the highest in 2013. The basic pests of birch in the northern cities were chewing phyllophages, especially Tenthredinidae sawflies.     

Assessment of the risk of excess sulfur input into terrestrial ecosystems of the Kola Peninsula

The tolerance of terrestrial ecosystems of the Kola Peninsula to atmospheric deposition of acid-forming sulfur compounds and the risk of their excess input into these ecosystems have been assessed on the basis of the critical load concept. The most sensitive ecosystems (critical sulfur load <400 equiv/ha per year) occupy 58% of the total area of the peninsula. These are mainly pine, spruce, and birch forests (including open and crooked birch forests) growing on podzols formed on sandy boulder-pebble glacial deposits. The zones of ecological risk cover the northwestern and central parts of the peninsula near the Pechenganikel and Severonikel combined works (20% of the total area).     

Chemical composition of <Emphasis Type="Italic">Juniperus sibirica</Emphasis> needles (Cupressaceae) in the forest–tundra ecotone,the Khibiny Mountains

The needles of juniper growing in spruce and birch forests of the Khibiny Mountains have been analyzed to evaluate the pattern of changes in their chemical composition (ADF, lignin, cellulose, lignin/cellulose, lipids, phenolic compounds, proanthocyanidins, flavonoids, N, C, and also Ca, Mg, K, Mn, Zn, P, S, Al, and Fe). It has been shown that the concentrations of lignin, lipids, phenolic compounds, Ca, Al, and Fe in the needles increase with age, while those of flavonoids, soluble and bound proanthocyanidins, N, P, K, Mg, Zn, and Mn decrease. The needles of juniper from spruce and birch forests differ in the contents of nutrient elements, which is explained by differences in the composition of soils. The contents of lignin, cellulose, and lipids in aging needles are lower in birch forests than in spruce forests.     

Dynamics of Trophic Activity of Leaf-Eating Insects on Birch during Reduction of Emissions from the Middle Ural Copper Smelter

The trophic activity of birch leaf-eating insects in background and impact (highly polluted) sites near the Middle Ural Copper Smelter has been recorded in 2008–2015. Reduction of emissions leads to a significant decrease in the concentration of heavy metals in birch leaves, and the existing differences in the proportion of damaged leaves between the background and impact sites are leveling off. An increasing temporal trend in foliar damage at the impact site confirms that the trophic activity of leaf-eating insects is being recovered following reduction of toxic load, and the remaining differences from the background territory indicate that this process is still continuing.     

Physiological Age of Host Plant Foliage and Survival of Gypsy Moth Larvae

The pH of leaf homogenates of common birch (Betula verrucosa L.), a food plant of gypsy moth (Lymantria dispar L.) larvae, was measured at different times of day in the course of leaf organogenesis, and midgut pH was measured in gypsy moth larvae phenotypically differing in the color of the hypodermis at the fifth instar. A possible relation between these parameters is discussed.     

Structural Changes in the Carabid Fauna of Forest Ecosystems under a Toxic Impact

Changes in the abundance, species composition, and biomorphological structure of the carabid fauna were studied in birch and fir–spruce forests growing in a zone exposed to emissions from a copper-smelting plant in the Middle Urals. The dynamic density of carabids decreased and their species composition and the ratio of life forms changed along the pollution gradient, but the principle of organization of carabidocenoses and the structure of dominance in them remained undisturbed.     

137Cs distribution among annual rings of different tree species contaminated after the Chernobyl accident

The distributions of 137Cs among annual rings of Pinus sylvestris and Betula pendula at four experimental sites located in the most contaminated areas in the Russian territory after the Chernobyl accident in 1986 were studied. Trees of different ages were sampled from four forest sites with different tree compositions and soil properties. The data analysis shows that 137Cs is very mobile in wood and the 1986 rings do not show the highest contamination. The difference between pine and birch in the pattern of radial 137Cs distribution can be satisfactorily explained by the difference in radial ray composition. 137Cs radial distribution in the wood can be described as the sum of two exponential functions for both species. The function parameters are height, age and species dependent. The distribution of 137Cs in birch wood reveals much more pronounced dependence on site characteristics and/or the age of trees than pines. The data obtained can be used to assess 137Cs content in wood.     

Comparison of 226Ra nuclide from soil by three woody species Betula pendula, Sambucus nigra and Alnus glutinosa during the vegetation period

The uptake of 226Ra from the contaminated soil was compared in three woody species: alder (Alnus glutinosa), birch (Betula pendula) and elder (Sambucus nigra). The 226Ra activities increased during the vegetation periods (in 2003, 2004 and 2005) both in the leaves and flowers+seeds. The highest accumulation was found in birch, reaching 0.41 Bq/g DW in the leaves (at the end of the vegetation period in 2003). The lowest 226Ra accumulation was determined in alder. The extent of 226Ra accumulation in the leaves of woody species demonstrates that these pioneer woody species can be used as remediation alternative to the use of herbs, provided that the removal of fallen leaves could be achieved in the end of vegetation period.