Soil formation and grouping of soils of the taiga zone in central West Siberia

Natural environments of the taiga zone in central West Siberia have been analyzed, with emphasis placed on the geological and morphological structure of the territory and morphology of soils. The main factors of soil formation are recognized, the main processes of soil formation are revealed, and a systematic list of soil kinds is compiled.     

Regeneration successions of northern taiga spruce forests under reduction of aerotechnogenic impact

The development of the composition and structure of northern taiga spruce forests on the Kola Peninsula under regeneration succession with a reduction in emissions from the metallurgical combine are described. Parameters of species diversity and ecological-coenotic structure of plant communities, including algosinusia of soils, are assessed under different technogenic impacts. Significant indices of stable transformations of plants from different layers during the regeneration succession were revealed. Strongly transformed communities in the vicinity of the combine are shown to remain in a critical state due to the preserved high level of soil pollution and demutation changes of the taiga components in the course of allogenic succession.     

The fleas of small mammals in the northern taiga of western Siberia

Data on the species composition of fleas, their abundance and distribution on hosts and on territory are given. Changes in the species composition and abundance of fleas in the latitude and meridional directions are shown.     

Transformation of soil organic matter in microarthropod community from the northern taiga of west Siberia

Recolonization of defaunated soil by springtails as well as by gamasid and oribatid mites and the changes in organic matter content of soil were studied in the northern taiga. After a one-year exposure in gauze bags (1.7 mm mesh), the abundance of microarthropods was higher but the number of species was lower compared to the surrounding soil. Large surface and litter forms did not colonize the samples, while the number of small and/or soil forms was higher. Soil samples inaccessible for microarthropods (0.15 mm mesh) were depleted of organic carbon compared to both surrounding soil and recolonized samples. The content of humic and fulvic acids was higher in the samples inaccessible to microarthropods. Humification processes prevailed in soils in the absence of microarthropods.     

Climatically induced interannual variability in aboveground production in forest-tundra and northern taiga of central Siberia

To investigate the variability of primary production of boreal forest ecosystems under the current climatic changes, we compared the dynamics of annual increments and productivity of the main components of plant community (trees, shrubs, mosses) at three sites in the north of Siberia (Russia). Annual radial growth of trees and shrubs was mostly defined by summer temperature regime (positive correlation), but climatic response of woody plants was species specific and depends on local conditions. Dynamics of annual increments of mosses were opposite to tree growth. The difference in climatic response of the different vegetation components of the forest ecosystems indicates that these components seem to be adapted to use climatic conditions during the short and severe northern summer, and decreasing in annual production of one component is usually combined with the increase of other component productivity. Average productivity in the northern forest ecosystems varies from 0.05 to 0.14 t ha⁻¹ year⁻¹ for trees, from 0.05 to 0.18 t ha⁻¹ year⁻¹ for shrubs and from 0.54 to 0.66 t ha⁻¹ year⁻¹ for mosses. Higher values of tree productivity combined with lower annual moss productivity were found in sites in northern taiga in comparison with forest-tundra. Different tendencies in the productivity of the dominant species from each vegetation level (trees, shrubs, mosses) were indicated for the last 10 years studied (1990–1999): while productivity of mosses is increasing, productivity of trees is decreasing, but there is no obvious trend in the productivity of shrubs. Our results show that in the long term, the main contribution to changes in annual biomass productivity in forest-tundra and northern taiga ecosystems under the predicted climatic changes will be determined by living ground cover.     

The role of soil cover in maintaining the structural and functional integrity of northern taiga ecosystems in Western Siberia

The soils of the studied area function in different temperature regimes: under the influence of permafrost (Turbic Histic Cryosol and Cryic Eutric Histosol) and long-term seasonal freezing (Albic Podsol). Sporadic permafrost defines the differences in temperature regimes. All soils are characterized by the low production of carbon dioxide (an average of 160 mg CO₂/(m² h)), indicating their low biological activity. The lack of easily available carbon for microorganisms is detected in all investigated soils by the C_mic: C_org ratio despite the high reserves of organic matter. The value of CO₂ emission and the C_mic: C_org ratio are “site-specific” for the region of investigation and may be used as indicators of environmental changes. Cryogenic peat soils represent a unique natural object and ensure the functional diversity and integrity of northern taiga ecosystems in Western Siberia.     

Testate amoebae inhabiting middle taiga bogs in Western Siberia

The population of testate amoebae from the most typical middle taiga bogs of Western Siberia have been studied. More than one hundred (103) species and intraspecific taxons of testate amoebae have been revealed in recent surface samples. The relation between ecological characteristics of habitats and the composition of a Protozoa population has been demonstrated. The ecological preferences of species concerning the index of wetness, ash level, and acidity have been revealed. Using the correspondence analysis, the ecological optimums and the tolerance of species and intraspecific taxons of testate amoebae have been established.     

Soil functioning in foci of Siberian moth population outbreaks in the southern taiga subzone of Central Siberia

The results of experimental studies on the contribution of zoogenic debris to transformation of soil properties in the southern taiga subzone of Central Siberia are analyzed. They show that water-soluble carbon outflow from the forest litter increases by 21–26% upon a Siberian moth invasion, with this value decreasing to 14% one year later. The burning of forest in an area completely defoliated by the pest leads to changes in the stock, fractional composition, actual acidity, and ash element contents of the litter. The litter-dwelling invertebrate assemblage is almost completely destroyed by fire and begins to recover only after two years.     

The structure of the micromycete complexes of oligotrophic peat deposits in the southern taiga subzone of West Siberia

The analysis of the micromycete complexes of oligotrophic peat deposits in the Vasyugan Marsh by direct count and culture methods showed that the micromycete carbon comprises no more than 3% of the total peat carbon and that the microscopic fungal biomass varies from 2 to 13 tons/hectare, depending on the season and the peat deposit thickness. Fungal spores were found in all layers of the peat deposits, whereas the mycelium was found only in the active peat layer. The high abundance of eukaryotic cells in the peats was due to the presence of yeastlike cells rather than fungal spores. Analyses by culture methods showed that micromycetes were present in all peat layers and that their abundance tended to decrease with depth, except for yeasts, which were uniformly distributed in a vertical direction. The micromycete complexes of the peat deposits were similar in the diversity and abundance of dominant species but differed in the composition of minor species. Peat yeasts were dominated by ascomycetes.     

The soils of West Siberia middle taiga oil deposits and a predictive estimate of contamination hazard with organic pollutants

Regularities of distribution of the background soils of oil deposits in the middle taiga of West Siberia have been studied and the features of their morphogenetic and physicochemical properties have been revealed. It has been experimentally substantiated that soil contamination hazard with oil components depends on the position of soil in the elementary landscape-geochemical systems (ELGS), on the granulometric composition, and buffer capacity. The results may be used to perform soil ecological monitoring and soil revegetation.     

Structure of plant communities in the early succession stages on anthropogenic sandy outcrops of the forest tundra and northern taiga of Western Siberia

The results of a study of the taxonomic, ecological, and phytocenotic structure of plant communities formed in the early stages of overgrowth of the anthropogenic sandy outcrops within the forest-tundra zone and northern taiga forest subzone of Western Siberia are presented. In the early stages of vegetativecover restoration, there are from 2 to 11 species growing into sparse communities of the classes Loiseleurio-Vaccinietea, Artemisietea vulgaris, and Koelerio-Corynephoretea. The participation of some meso-xerophytic forest-tundra, meadow-margin, and weed herbaceous plant and dwarf shrubs species, mostly with ruderal and stress-tolerant eco-phytocenotic strategies, as well as with secondary strategies—violent-ruderal and ruderal–stress-tolerant—in the secondary succession on the sandy outcrops have been shown. The primary succession begins at the bottom and slopes of the pit ditches, as well on the surface of the sand dunes, and proceeds at an accelerated scenario. Hygro-, meso- and xerophilous species, predominantly oligo-mesotrophic rhizome and densely firm-bunch grasses and shrubs of the native flora, as well as ground lichens, participate in the early stages of succession.     

Lichen biota of West Siberia

The author has surveyed the diversity of lichen biota of West Siberia and distribution of lichens over its two geographic parts: the West Siberian Plain and the mountain frame in the south of West Siberia. The diversity of lichen biota in entire West Siberia is currently estimated at 1845 species in 325 genera and 95 families. The diversity of the West Siberian Plain is estimated at 1421 species in 271 genera and 86 families, and that of the southern mountains of West Siberia, at 1682 species in 312 genera and 94 families.     

Greenhouse gas emission in West Siberia

The major gases contributing to the greenhouse effect are carbon dioxide and methane (60 and 15–18%, respectively). The former Soviet Union area accounts for 11% of the global methane flux on the average. However, virtually no records of methane flux were kept in Russia in the late 1980s-early 1990s. Inventories of methane emission in Russia were reported in the middle 1990s, but those data were confined to measurements performed by the early 1990s. This paper presents generalized data on methane and carbon dioxide emission from the surfaces of marsh ecosystems in West Siberia in the 1990s, when the majority of measurements were carried out.     

Chromosomal Q-heterochromatin regions in the indigenous population of the northern part of West Siberia and in new migrants

The variability of Q-heterochromatin regions (Q-HR) was studied in native residents of the northern part of West Siberia, viz Yakuts (n = 127), Selkups (n = 90) and Khants (n = 54), as well as in newcomers including oil-borers (n = 43) and children (n = 113) living permanently in this part of the USSR. The major quantitative characteristics of chromosomal Q-HR variability were shown to be very similar in oil-borers and natives, and this is considered to be the result of specific selection of individuals according to the amount of Q-HRs in their genome. The hypothesis on the possible selective value of chromosomal Q-HRs in human adaptation to extreme environmental conditions of the extreme north is discussed.     

Early post-fire tree regeneration in a Picea-Vaccinium forest in northern Sweden

Abstract. Age and size structure of saplings of Picea abies, Pinus sylvestris and Betula pubescens were examined in a 26-yr old forest fire area in a Picea abies-Vaccinium myrtillus forest in northern Sweden. Picea, which is a shade-tolerant species, had its maximum regeneration prior to the shade-intolerant Pinus. The shift from Picea to Pinus regeneration in the late 1970s, did not seem to be related to variations in summer temperature. Instead, it is suggested that Picea established in the shade created by dead trees, and, that increased reindeer browsing of Betula in combination with a simultaneous thinning of the tree layer, favoured Pinus recruitment. These regeneration patterns do not confirm conventional views of post-fire succession in Sweden.     

The carbon balance in natural and disturbed forests of the southern taiga in central Siberia

Abstract. We evaluated the balance of production and decomposition in natural ecosystems of Pinus sylvestris, Larix sibirica and Betula pendula in the southern boreal forests of central Siberia, using the Yenisei transect. We also investigated whether anthropogenic disturbances (logging, fire and recreation pressure) influence the carbon budget. Pinus and Larix stands up to age class VI act as a net sink for atmospheric carbon. Mineralization rates in young Betula forests exceed rates of uptake via photosynthesis assimilation. Old‐growth stands of all three forest types are CO₂ sources to the atmosphere. The prevalence of old‐growth Larix in the southern taiga suggests that Larix stands are a net source of CO₂. The CO₂ flux to the atmosphere exceeds the uptake of atmospheric carbon via photosynthesis by 0.23 t C.ha^‐1.yr^‐1 (47%). Betula and Pinus forests are net sinks, as photosynthesis exceeds respiration by 13% and 16% respectively. The total carbon flux from Pinus, Larix and Betula ecosystems to the atmosphere is 10 387 thousand tons C.yr^‐1. Net Primary Production (0.935 t‐C.ha^‐1) exceeds carbon release from decomposition of labile and mobile soil organic matter (Rh) by 767 thousand tons C (0.064 t‐C.ha^‐1), so that these forests are net C‐sinks. The emissions due to decomposition of slash (101 thousand tons C; 1.0%) and from fires (0.21%) are very small. The carbon balance of human‐disturbed forests is significantly different. A sharp decrease in biomass stored in Pinus and Betula ecosystems leads to decreased production. As a result, the labile organic matter pool decreased by 6–8 times; course plant residues with a low decomposition rate thus dominate this pool. Annual carbon emissions to the atmosphere from these ecosystems are determined primarily by decomposing fresh litterfall. This source comprises 40–79% of the emissions from disturbed forests compared to only 13–28% in undisturbed forests. The ratio of emissions to production (NPP) is 20–30% in disturbed and 52–76% in undisturbed forests.     

Characteristics of opisthorchiasis foci in southern West Siberia

Natural foci of opistorchiasis were studied in southern West Siberia. It has been shown that the foci are of two biocenotic groups: floodplain-river and lake-interfluve. The main difference between them is that in the former intermediate hosts of opistorchides are commercial Cyprinidae fish and final hosts are humans and domestic carnivores, whereas in the latter, intermediate hosts are noncommercial Cyprinidae fish, wild carnivores, and muskrat. Floodplain-river foci are associated with river basins in the north of Baraba, big and small tributaries of the Ob and Irtysh rivers, as well as euthrophic lakes within floodplains of the rivers. Lake-interfluve foci are associated with euthrophic and dystrophic lakes in the river floodplains which do not communicate with the Ob-Irtysh water system. They are located in North Kulunda and in the south of Baraba lowland.     

Methanotrophic communities in the soils of Russian northern taiga and subarctic tundra

The PCR analysis of DNA extracted from soil samples taken in Russian northern taiga and subarctic tundra showed that the DNA extracts contain genes specific to methanotrophic bacteria, i.e., the mmoX gene encoding the conserved alpha-subunit of the hydroxylase component of soluble methane monooxygenase, the pmoA gene encoding the alpha-subunit of particulate methane monooxygenase, and the mxaF gene encoding the alpha-subunit of methanol dehydrogenase. PCR analysis with group-specific primers also showed that methanotrophic bacteria in the northern taiga and subarctic tundra soils are essentially represented by the type I genera Methylobacter, Methylomonas, Methylosphaera, and Methylomicrobium and that some soil samples contain type II methanotrophs close to members of the genera Methylosinus and Methylocystis. The electron microscopic examination of enrichment cultures obtained from the soil samples confirmed the presence of methanotrophic bacteria in the ecosystems studied and showed that the methanotrophs contain only small amounts of intracytoplasmic membranes.     

Gas-resistance of the woody plants of West Siberia

A resistant of the woody plants in West Siberia to toxic substances (sulfur dioxide, hydrocarbons, and carbon black) is studied by the reaction of the pigment complex, change of acidity of the leaf blade, activity of oxidative enzymes, moisture regime, and degree of damage of the leaf blade. The data of the study can be used in the landscaping of the sanitary protective zones of enterprises.     

Soil seed bank dynamics in post-fire heathland succession in south-eastern Australia

Soil seed banks can exert a strong influence on the path of vegetation succession following fire, with species varying in their capacity to persist in the seed bank over time, leading to changes in seed bank composition and propagules available for post-fire colonisation. This study examined the effect of time since fire on soil seed bank dynamics in a chronosequence of seven sites spanning 26 years in a south-eastern Australian sand heathland. No significant change was evident in the species richness and density of the germinable soil seed bank, but species composition differed significantly among young (0–6 years since fire), intermediate (10–17 years since fire) and old-aged (24–26 years since fire) sites (using presence/absence data). No significant trend was observed in the similarity between the extant vegetation and the soil seed bank with time since fire. A total of 32% of the species recorded in the soil seed bank were not present in the above-ground vegetation at the same site, which suggests that species requiring fire for germination may be present in the seed bank. Most species present in the extant vegetation were not recorded (63%) or were in very low abundances in the soil seed bank (29%). The mode of regeneration appears to be the major determinant of species absence in the soil seed bank, as 66% of species occurring in the extant vegetation but not in the seed bank have the capacity to regenerate by resprouting. This study shows that a major shift in the successional pathway after fire due to altered seed bank composition is unlikely in this vegetation; most species not recorded in the seed bank are either resprouters (obligate or facultative) or serotinous, suggesting that they will readily regenerate following fire. Unless fire frequencies are high and kill fire-sensitive obligate seeders before they reach maturity, the chance that the soil seed bank could substantially alter vegetation composition within the study area after fire is low. However, it is unclear how successional pathways may alter in response to severe fires with the potential to kill both seeders and resprouters.