Central Siberia Research Articles

Assessment of spatial variability of agrochemical properties of agro-gray soil when planning a feld experiment with mineral fertilizers

The purpose of the work is to investigate the statistical parameters and patterns of variability of agrochemical indicators of agro–gray soil, elements of the structure of the spring wheat crop within the plots of the experimental field. Experimental data were obtained on the basis of observations conducted on agricultural landscapes Sukhobuzimskoye land areas in the Krasnoyarsk forest-steppe of the Krasnoyarsk geomorphological district, located borders the Chulym-Yenisei denudation plateau in the southwestern outskirts of Central Siberia. The results of the intra-field heterogeneity of the agrochemical properties of the agro-gray soil and the elements of the structure of the spring wheat crop on the site intended for field experiment are presented. The key statistical and geostatistical values of the intrafield heterogeneity are determined. The statistics of agrochemical indicators and the results of crop data from the plots intended for the placement of repetitions are analyzed. The materials of the agrochemical survey of the agro-gray soil revealed a low humus content. The level of spatial variation of the indicator corresponded to the average. The scope of variation is represented by values covering only one gradation of the evaluation scale. The entire studied area was characterized by a slightly acidic reaction of the medium according to the average pH values. Its variation in the 0-20 cm soil layer indicated uniformity of distribution in space. The level of variability of agrochemical indicators decreased in the following series: yield (40 %) > humus (19 %) > P2O5 (13 %) > K2O (10 %) > pH2O (4 %). According to the generalization of geostatistical information, the analyzed site is classified as unaligned in terms of soil fertility. In general, the soil fertility of the studied area had a significant variation, which determined the choice of elements of the field experience methodology. When laying out field experience, it is necessary to choose the appropriate elements of the methodology: a randomized method of placing repetitions, rectangular or elongated forms of plots.

Genetic aspects of lactase deficiency in indigenous populations of Siberia.

The ability to metabolize lactose in adulthood is associated with the persistence of lactase enzyme activity. In European populations, lactase persistence is determined mainly by the presence of the rs4988235-T variant in the MCM6 gene, which increases the expression of the LCT gene, encoding lactase. The highest rates of lactase persistence are characteristic of Europeans, and the lowest rates are found in East Asian populations. Analysis of published data on the distribution of the hypolactasia-associated variant rs4988235-C in the populations of Central Asia and Siberia showed that the frequency of this variant increases in the northeastern direction. The frequency of this allele is 87 % in Central Asia, 90.6 % in Southern Siberia, and 92.9 % in Northeastern Siberia. Consequently, the ability of the population to metabolize lactose decreases in the same geographical direction. The analysis of paleogenomic data has shown that the higher frequency of the rs4988235-T allele in populations of Central Asia and Southern Siberia is associated with the eastward spread of ancient populations of the Eastern European steppes, starting from the Bronze Age. The results of polymorphism analysis of exons and adjacent introns of the MCM6 and LCT genes in indigenous populations of Siberia indicate the possibility that polymorphic variants may potentially be related to lactose metabolism exist in East Asian populations. In East Asian populations, including Siberian ethnic groups, a ~26.5 thousand nucleotide pairs long region of the MCM6 gene, including a combination of the rs4988285-A, rs2070069-G, rs3087353-T, and rs2070068-A alleles, was found. The rs4988285 and rs2070069 loci are located in the enhancer region that regulates the activity of the LCT gene. Analysis of paleogenomic sequences showed that the genomes of Denisovans and Neanderthals are characterized by the above combination of alleles of the MCM6 gene. Thus, the haplotype discovered appears to be archaic. It could have been inherited from a common ancestor of modern humans, Neanderthals, and Denisovans, or it could have been acquired by hybridization with Denisovans or Neanderthals. The data obtained indicate a possible functional significance of archaic variants of the MCM6 gene.

Skillful Long-Lead Seasonal Predictions in the Summertime Northern Hemisphere Midlatitudes

Abstract In contrast to boreal winter when extratropical seasonal predictions benefit greatly from ENSO-related teleconnections, our understanding of forecast skill and sources of predictability in summer is limited. Based on 40 years of hindcasts of the Canadian Seasonal to Interannual Prediction System, version 3 (CanSIPSv3), this study shows that predictions for the Northern Hemisphere summer surface air temperature are skillful more than 6 months in advance in several midlatitude regions, including eastern Europe–Middle East, central Siberia–Mongolia–North China, and the western United States. These midlatitude regions of statistically significant predictive skill appear to be connected to each other through an upper-tropospheric circumglobal wave train. Although a large part of the forecast skill for the surface air temperature and 500-hPa geopotential height is attributable to the linear trend associated with global warming, there is significant long-lead seasonal forecast skill related to interannual variability. Two additional idealized hindcast experiments are performed to help shed light on sources of the long-lead forecast skill using one of the CanSIPSv3 models and its uncoupled version. It is found that tropical ENSO-related sea surface temperature (SST) anomalies contribute to the forecast skill in the western United States, while land surface conditions in winter, including snow cover and soil moisture, in the Siberian and western U.S. regions have a delayed or long-lasting impact on the atmosphere, which leads to summer forecast skill in these regions. This implies that improving land surface initial conditions and model representation of land surface processes is crucial for the further development of a seasonal forecasting system. Significance Statement Useful seasonal predictions in the boreal summer midlatitude regions are of great value. In this study, we show that predictions for the boreal summer season are skillful more than 6 months in advance in several midlatitude regions, including eastern Europe–Middle East, central Siberia–Mongolia–North China, and the western United States. The forecast skill in these regions is associated with a circumglobal teleconnection atmospheric circulation pattern. Sources of the long-lead forecast skill include the global warming–related trend and anomalies in the ocean and land surface initial conditions. It is found that the wintertime snow cover and soil moisture in the Siberian and western U.S. regions have a delayed or long-lasting impact on the atmosphere, which leads to summer forecast skill.

A sex chromosome polymorphism maintains divergent plumage phenotypes between extensively hybridizing yellowhammers (Emberiza citrinella) and pine buntings (E. leucocephalos).

Under allopatric speciation, populations of a species become isolated by a geographic barrier and develop reproductive isolation through genetic differentiation. When populations meet in secondary contact, the strength of evolved reproductive barriers determines the extent of hybridization and whether the populations will continue to diverge or merge together. The yellowhammer (Emberiza citrinella) and pine bunting (E. leucocephalos) are avian sister species that diverged in allopatry on either side of Eurasia during the Pleistocene glaciations. Though they differ greatly in plumage and form distinct genetic clusters in allopatry, these taxa show negligible mitochondrial DNA differentiation and hybridize extensively where they overlap in central Siberia, lending uncertainty to the state of reproductive isolation in the system. To assess the strength of reproductive barriers between taxa, we examined genomic differentiation across the system. We found that extensive admixture has occurred in sympatry, indicating that reproductive barriers between taxa are weak. We also identified a putative Z chromosome inversion region that underlies plumage variation in the system, with the 'pine bunting' haplotype showing dominance over the 'yellowhammer' haplotype. Our results suggest that yellowhammers and pine buntings are currently at a crossroads and that evolutionary forces may push this system towards either continued differentiation or population merging. However, even if these taxa merge, recombination suppression between putative chromosome Z inversion haplotypes may maintain divergent plumage phenotypes within the system. In this way, our findings highlight the important role hybridization plays in increasing the genetic and phenotypic variation as well as the evolvability of a system.

An Interseasonal Comparison of Soil Respiration in Xeric and Mesic Pine Forest Ecosystems in Central Siberia

An understanding of how boreal forest composition responds to global environmental changes is an important challenge to predicting the future global carbon balance. Boreal forests are the most significant sink for atmospheric carbon dioxide; however, their sequestration capacity is highly sensitive to ongoing climate changes. The combination of the hydrothermal conditions of a territory strongly regulates its biogeochemical processes. The carbon fluxes in boreal forests are strongly mediated by the ground vegetation cover, composed of mosses (mesic) and lichens (xeric). Despite the concurrence of xeric and mesic vegetation types, their responses to climate variations varies significantly. Soil emission is an informative indicator of ecosystem functioning. In this study, we focused on the soil CO2 dynamics during frost-free seasons with different precipitation regimes in the xeric and mesic boreal ecosystems of Central Siberia. Seasonal measurements of soil CO2 emissions were conducted during frost-free seasons using the dynamic chamber method. Our findings reveal that the precipitation regimes of each year may control the seasonal soil emission dynamics. The soil moisture is the most important driver of emissions growth in the water-limited lichen pine forest (R2adj. = 18%). The soil temperature plays the largest role in the feather moss pine forest during the dry (R2adj. = 31%) seasons, and in the lichen pine forest during the wet (R2adj. = 41%) seasons. The cumulative efflux for the xeric and mesic sites is mostly related to the hydrothermal conditions, and not to the differences in ground vegetation cover. During the dry seasons, on average, the soil CO2 emissions are 45% lower than during the wet seasons for both sites. These findings emphasize the need for estimating and including the hydrothermal characteristics of the growing season for detailed emission assessments.

Escalating Wildfires in Siberia Driven by Climate Feedbacks Under a Warming Arctic in the 21st Century

AbstractSiberian wildfire is of paramount importance in the carbon cycle and climate change as it is a major disturbance in the pan‐Arctic ecosystems. In recent decades, the Siberian wildfire regime has been shifting; however, less is known about its process‐based feedback mechanisms. By integrating in‐situ and satellite observational data sets as well as chemistry‐climate coupled modeling, we find that central Siberia has featured the most prominent wildfire escalation during the past two decades, which is closely related to hydrological drought with decreasing rainfall and drying soil under a fast‐warming Arctic. Furthermore, fire‐emitted aerosols compound the increasing wildfires via serving as cloud condensation nuclei and suppressing precipitation, forming self‐amplifying feedback. As the Arctic warming is projected to continue, wildfires are estimated to more than double by the end of this century. This work highlights the great importance of fire risk management based on a fundamental scientific understanding of the complex climate system.

ПОЧВЕННЫЕ БАКТЕРИИ ИЗ АВТОХТОННЫХ МИКРОБНЫХ СООБЩЕСТВ ЦЕНТРАЛЬНОЙ СИБИРИ В БИОЛОГИЧЕСКОЙ ЗАЩИТЕ ПШЕНИЦЫ ОТ ALTERNARIA TENUISSIMA

The most powerful soil bacteria from autochthonous microbial communities of Central Siberia against phytopathogenic fungi Alternaria tenuissima were selected. Isolation from soil samples and cultivation of bacterial isolates were performed on the artificial nutrient medium for bacteria PD-agar. Antagonistic activity was measured on GRM Saburo. In this case, Alternaria tenuissima was sown in a dish on GRM Saburo, and the selected bacterial strains were sown around the micromycete. As a result of joint growth of the test culture and soil bacteria, the most powerful antagonists in the suppression zone of Alternaria tenuissima were identified. The most powerful bacteria-antagonists in reducing the intensity and prevalence of root rot were identified by the method of artificial infection of Alternaria tenuissima. Before infection with micromycete, bacterization of spring wheat seeds Novosibirskaya-15 with the studied bacterial isolates was carried out. Mathematical processing of the obtained results was fulfilled by one-way variance analysis and two-sample F-test for variance. The results of the study on the use of soil autochthonous antagonist microorganisms in biological protection of spring wheat from the causative agents of root rot Alternaria tenuissima showed that the studied bacterial isolates statistically significantly (p < 0.01) reduced the intensity and prevalence of this disease. The maximum effect in reducing the intensity and prevalence of the disease was shown by isolates B2 and B4 (according to preliminary identification of Bacillus sp.). Also, the studied bacterial strains showed a positive effect on the length of sprouts. At the same time, isolate B2 showed a statistically significant (p < 0.001) effect on the length of spring wheat sprouts. The stimulating effect was manifested in an increase in the length of sprouts compared to the control. Therefore, this strain can be recommended not only for protection against Alternaria tenuissima, but also for stimulating wheat growth.

Who Were the Chagyrskaya Neanderthals? The Possibility of Their Dispersal Across Central Asia and Southern Siberia

My article in the previous issue, based on findings of archaeological excavations of Paleolithic sites in the Altai, primarily in Denisova Cave, as well as facts concerning the time of origin of Neanderthal anatomy and genetics in Europe, challenged the view, based on the genetic analysis of the Altaian Neanderthals, that they had migrated to the Altai before 175 ka BP and occupied Denisova Cave by turns with Denisovans. In fact, the Neanderthal occupation of the Altai began apparently no earlier than 60 ka BP. Thus far, Neanderthal fossils with a Micoquian Mousteroid industry have been found in three caves: Chagyrskaya, Okladnikov, and Strashnaya. This group of Neanderthals, evidencing the easternmost dispersal wave of those humans in Asia, was termed the Chagyrskaya group.

Connections of the Yamna Culture Population of the Black Sea Region According to Anthropological Data: An Intergroup Analysis of Male Series

The objective of this paper is to examine the population history of the North Pontic Yamna groups through an analysis of phenotypic variation in cranial morphology. To investigate this issue, an intergroup analysis of male craniological samples from Eastern, Central, South-Eastern Europe, Caucasus and Southern Siberia was carried out using the multidimensional scaling method. The analysis suggests that migrations were a significant factor in the formation of the Yamna culture phenomenon in the vast steppe areas of Eurasia. This can explain the anthropological continuity of Yamna-related groups and the central position of the Volga steppe region within it. While there is a variability in anthropological characteristics, most Yamna-related series share a number of common features. The morphological variability observed in Yamna populations can be attributed to the extensive geographical distribution of the Yamna horizon and its interaction with local and neighbouring tribes in various regions. The Yamna horizon likely originated from steppe Eneolithic groups, particularly those with morphological similarities to the Repin and Serednii Stih populations. The Maikop-Novosvobodnaia groups may have also played a role in the formation of the Yamna horizon. The origin of the broad-faced dolichomesocranial craniocomplex, found in Yamna material from the North Pontic region, can be linked to the eastern Yamna groups. A different leptene hyperdolichocranial craniocomplex can be associated with the later groups of the Ural and Cis-Caucasian regions, such as the Tamar-Utkul group and possibly the Novotitorovka culture. However, it can also be assumed that the North Pontic Yamna population was influenced by Central European groups (Funnelbeaker, Globular Amphora, Corded Ware cultures) as well as the Kemi-Oba population, whose origin can also be linked to the Central European cultural circle.

Fauna and Ecology of Macromycetes (Basidiomycota) in the Arctic Tree and Shrub Ecosystems of Central Siberia.

The research was aimed at studying the taxonomic diversity, habitat specialization, and trophic characteristics of mycobiota, including Basidiomycota, in the northern ecosystems of the Krasnoyarsk Krai (Central Siberia) near Norilsk. Larch forests and woodlands in the Siberian permafrost zone are distinctive and Basidiomycota, as a component of these ecosystems, plays an essential role in their functioning. Currently, there is a paucity of information about this group in Arctic ecosystems, both in terms of floristic and ecological aspects. Seventy species of macromycetes belonging to different trophic groups were discovered and identified. Only 15% of species occur regularly, while most species are found rarely or only once. The identified species belong to 44 genera, 25 families, and 8 orders, which are included in the class Agaricomycetes. The leading families in terms of the number of species are Russulaceae, Polyporaceae, Tricholomataceae, Suillaceae, Strophariaceae, and Cortinariaceae. Mycorrhizal fungi and wood decay fungi dominate the structure of mycobiota of the study area (the total share is 71%). The rest of the species (29%) are fungal decomposers inhabiting plant litter, the forest floor, and humus. The largest number of species occur in forest ecosystems, which are dominated by mycorrhizal and wood decay fungi (up to 70%), which are trophically associated with woody plants and debris. The fungal decomposers inhabiting plant litter, the forest floor, and humus dominate (about 80%) in the species composition of tundra, where, in the absence of woody substrate, wood decay fungi have not been found at all. The species richness of tree and shrub Arctic ecosystems is low, yet the taxonomical and ecological structure of Basidiomycota is similar to that observed in taiga and temperate forests. These data permit a more comprehensive description of the biodiversity of the Arctic and may prove useful in studying biological processes in these ecosystems.

Avirulence of a spontaneous Francisella tularensis subsp. mediasiatica prmA mutant.

Francisella tularensis, the causative agent of tularemia, is divided into three subspecies. Two of these, subspecies holarctica and tularensis, are highly pathogenic to humans and consequently relatively well studied. The third subspecies, mediasiatica, is rarely isolated and remains poorly studied. It is distributed in the sparsely populated regions of Central Asia and Siberia. Curently this subspecies is not known to have been responsible for human infections in spite of its high virulence in laboratory animals. Subspecies mediasiatica is currently divided into three subgroups-MI, present in Central Asia, MII, present in southern Siberia, and MIII represented by a unique strain, 60(B)57, isolated in Uzbekistan in 1960. We describe here the unexpected observation that MIII strain 60(B)57 is avirulent and immunogenic. We observed that infection with this strain protected mice from challenge 21 days later with a virulent subsp. mediasiatica strain. With an increase of this interval, the protection for mice was significantly reduced. In contrast, guinea pigs were protected from challenge with strains of the subspecies holarctica and mediasiatica (but not subsp. tularensis) 90 days after infection with 60(B)57. We performed genome assembly based on whole genome sequencing data obtained using the Nanopore MinION for strain 60(B)57 and two subsp. mediasiatica strains representing the Central Asian MI and Siberian MII phylogenetic subgroups. The prmA gene is truncated due to a nonsense mutation in strain 60(B)57. The deletion of gene prmA has previously been shown to induce a loss of virulence in Francisella novicida the closest model organism suggesting that the observed mutation might the cause of the avirulence of strain 60(B)57.

Multi-Source Dataset Assessment and Variation Characteristics of Snow Depth in Eurasia from 1980 to 2018

Snow is an indicator of climate change. Its variation can affect surface energy, water balance, and atmospheric circulation, providing important feedback on climate change. There is a lack of assessment of the spatial characteristics of multi-source snow data in Eurasia, and these data exhibit high spatial variability and other differences. Therefore, using data obtained from the Global Historical Climatology Network Daily (GHCND) from 1980 to 2018, snow depth information from ERA5, MERRA2, and GlobSnow is assessed in this study. The spatiotemporal variation characteristics and the primary spatial modes of seasonal variations in snow depth are analyzed. The results show that the snow depth, according to GlobSnow data, is closer to that of the measured site data, while the ERA5_Land and MERRA2 data are overestimated. The annual variations in snow depth are consistent with seasonal variations in winter and spring, with an increasing trend in the mountains of Central Asia and Siberia and a decreasing trend in most of the rest of Eurasia. The dominant patterns of snow depth in late autumn, winter, and spring are all north–south dipole patterns, and there is overall consistency in summer.

Particular, the content of heavy metals in drinking water in the south of Central Siberia

One of the conditions for the normal functioning of a living organism is a constant supply of clean and high-quality drinking water. This is also true for the population. Therefore, during the study, the characteristics of the content of heavy metals in drinking water in the south of Central Siberia were studied. During the work, the following tasks were solved: the content of heavy metals in drinking water was determined; the obtained values were compared with the maximum permissible concentrations of heavy metals; peculiarities of the content of heavy metals in various regions of the south of Central Siberia were identified. During the study, the following results were obtained. The water used for household and drinking needs by the population of the region is safe for use, since the maximum permissible concentrations for heavy metals are not exceeded. However, it can be noted that water samples taken in villages reveal a higher average content of the studied metals. The highest content in drinking water is typical for zinc, but the given values do not exceed the maximum permissible concentration for this element (5 mg/ml). The lowest content in the studied water samples is typical for mercury, the maximum permissible concentration for which is 0.0005 mg/ml.

ПОЧВЕННЫЕ БАКТЕРИИ ИЗ АВТОХТОННЫХ МИКРОБНЫХ СООБЩЕСТВ ЦЕНТРАЛЬНОЙ СИБИРИ В БИОЛОГИЧЕСКОЙ ЗАЩИТЕ ПШЕНИЦЫ ОТ ALTERNARIA TENUISSIMA

The aim of the study is to find the strongest soil microorganisms from autochthonous microbial communities of Central Siberia against phytopathogenic micromycetes Alternaria tenuissima. The object of the study is autochthonous soil bacteria isolated from the soils of the Krasnoyarsk forest-steppe in the Sukhobuzimsky District. Soil samples were taken from under spring wheat Novosibirskaya 15 and from under perennial grasses. The soil cover is represented by ordinary leached chernozem. Ammonium nitrate was used (34.7 kg/ha active ingredient). The climatic conditions are moderately dry and continental. The studies were carried out in 2022–2023. Antagonistic activity was measured on the GRM Saburo. With a general growth of the test culture and soil bacteria, the strongest antagonists were found in the suppression zone of Alternaria tenuissima. The identification of the most powerful bacterial antagonists in reducing the intensity and prevalence of root rot was carried out using the method of artificial infection with Alternaria tenuissima. Before infection with micromycete, bacterization of spring wheat seeds Novosibirskaya 15 with the studied bacterial isolates was carried out. Mathematical processing of the obtained results was carried out by one-way variance analysis and two-sample F-test for variance. The results of the study on the use of soil autochthonous antagonist microorganisms in biological protection of spring wheat from the causative agents of root rot Alternaria tenuissima showed that the studied bacterial isolates statistically significantly (p < 0.01) reduced the intensity and prevalence of this disease. The maxi-mum effect in reducing the intensity and prevalence of the disease was shown by isolates B2 and B4. Also, the studied bacterial strains showed a significant effect (p < 0.001) on the length of sprouts. The greatest increase in length in spring wheat sprouts was in the experimental variant with strain B2. This strain can be recommended not only for protection against Alternaria tenuissima, but also for stimuli-ting wheat growth.

From Siberia to Indonesia: tracking the migration of the Arctic Warbler Phylloscopus borealis

Little is known regarding the migration routes of Siberian songbird populations. Here we provide the first geolocator tracking data for an Arctic Warbler breeding in Central Siberia and compare its movements with eight long-distance ring recoveries of this species. In autumn, the tracked individual migrated eastward to a stopover site in eastern Siberia, before migrating southward through Taiwan to its non-breeding sites in the Philippines and Indonesia. During spring migration, the bird spent at least one month at stopover sites in Mongolia, before migrating to its breeding site in June. Ring recovery data confirmed the movement between the Central Siberian breeding grounds and stopover sites in northern Mongolia.

Comparative plastome analysis and taxonomic classification of snow lotus species (Saussurea, Asteraceae) in Central Asia and Southern Siberia

Four species of Saussurea, namely S. involucrata, S. orgaadayi, S. bogedaensis, and S. dorogostaiskii, are known as the “snow lotus,” which are used as traditional medicines in China (Xinjiang), Kyrgyzstan, Mongolia, and Russia (Southern Siberia). These species are threatened globally, because of illegal harvesting and climate change. Furthermore, the taxonomic classification and identification of these threatened species remain unclear owing to limited research. The misidentification of medicinal species can sometimes be harmful to health. Therefore, the phylogenetic and genomic features of these species need to be confirmed. In this study, we sequenced five complete chloroplast genomes and seven nuclear ITS regions of four snow lotus species and other Saussurea species. We further explored their genetic variety, selective pressure at the sequence level, and phylogenetic relationships using the chloroplast genome, nuclear partial DNA sequences, and morphological features. Plastome of the snow lotus species has a conserved structure and gene content similar to most Saussurea species. Two intergenic regions (ndhJ–ndhK and ndhD-psaC) show significantly high diversity among chloroplast regions. Thus, ITS and these markers are suitable for identifying snow lotus species. In addition, we characterized 43 simple sequence repeats that may be useful in future population genetic studies. Analysis of the selection signatures identified three genes (rpoA, ndhB, and ycf2) that underwent positive selection. These genes may play important roles in the adaptation of the snow lotus species to alpine environments. S. dorogostaiskii is close to S. baicalensis and exhibits slightly different adaptation from others. The taxonomic position of the snow lotus species, confirmed by morphological and molecular evidence, is as follows: (i) S. involucrata has been excluded from the Mongolian flora due to misidentification as S. orgaadayi or S. bogedaensis for a long time; (ii) S. dorogostaiskii belongs to section Pycnocephala subgenus Saussurea, whereas other the snow lotus species belong to section Amphilaena subgenus Amphilaena; and (iii) S. krasnoborovii is synonymous of S. dorogostaiskii. This study clarified the speciation and lineage diversification of the snow lotus species in Central Asia and Southern Siberia.

Detection of two species of non-indigenous freshwater snails in Arctic Siberia

ABSTRACT Some species of freshwater gastropods, known for their adaptability and resilience, have gained attention globally as invasive species. However, to date, only one invasive population of freshwater snails has been documented beyond the Arctic Circle. In this study, we report the discovery of two non-indigenous species, Planorbella duryi (Wetherby, 1879) and Physella acuta (Draparnaud, 1805), north of 69°N in the Norilsk Industrial District (Central Siberia). Their identification was based on morphological features and COI gene sequences. Both species are native to the temperate and subtropical zones of North America and may have entered the Arctic Asian reservoirs through aquarium introductions. The distribution of these populations is constrained to areas affected by thermal pollution, and their further spread into pristine reservoirs of Northern Siberia is unlikely.

The Pulses of Soil CO2 Emission in Response to Rainfall Events in Central Siberia: Revisiting the Overall Frost-Free Season CO2 Flux

Boreal forests nowadays act as a sink for atmospheric carbon dioxide; however, their sequestration capacity is highly sensitive to weather conditions and, specifically to ongoing climate warming. Extreme weather events such as heavy rainfalls or, conversely, heat waves during the growing season might perturb the ecosystem carbon balance and convert them to an additional CO2 source. Thus, there is an urgent need to revise ecosystem carbon fluxes in vast Siberian taiga ecosystems as influenced by extreme weather events. In this study, we focused on the soil CO2 pulses appearing after the rainfall events and quantification of their input to the seasonal cumulative CO2 efflux in the boreal forests in Central Siberia. Seasonal measurements of soil CO2 fluxes (both soil respiration and net soil exchange) were conducted during three consecutive frost-free seasons using the dynamic chamber method. Seasonal dynamics of net soil exchange fluxes demonstrated positive values, reflecting that soil respiration rates exceeded CO2 uptake in the forest floor vegetation layer. Moreover, the heavy rains caused a rapid pulse of soil emissions and, as a consequence, the release of additional amounts of CO2 from the soil into the atmosphere. A single rain event may cause a 5–11-fold increase of the NSE flux compared to the pre-rainfall values. The input of CO2 pulses to the seasonal cumulative efflux varied from near zero to 39% depending on precipitation patterns of a particular season. These findings emphasize the critical need for more frequent measurements of soil CO2 fluxes throughout the growing season which capture the CO2 pulses induced by rain events. This approach has inevitable importance for the accurate assessment of seasonal CO2 soil emissions and adequate predictions of response of boreal pine forests to climatic changes.

Репродуктивные показатели липы Нащокина (Tilia nasczokinii Stepanov)

Tilia nasczokinii Stepanov (Naszokin’s lime) is endemic to the south of the Krasnoyarsk Territory and is of relict origin. Two of its populations grow in the vicinity of Krasnoyarsk on the left and right banks of the Yenisey River, being a part of pine forests and mixed pine-deciduous herb forests. The total number of the species is about 500 plant units, of which only 43 plants are currently bearing fruit. This research has determined the sizes and qualitative characteristics of T. nasczokinii fruits and seeds. The lime-capsules of T. nasczokinii, for 2 populations in general, have had the length of 5.7 ± 0.026 mm and the width of 5.0 ± ± 0.017 mm. The seeds have had the length of 3.6 ± 0.019 mm and the width of 2.9 ± 0.015 mm. It has been established that the lime-capsules in the left bank population are characterized by an elongated pear-shaped form, while in the right bank population the lime-capsules are spherical and slightly pointed at the top. In terms of the size of lime-capsules and seeds, T. nasczokinii did not differ statistically from the introduced T. cordata, which grows in the plantation under similar environmental conditions. In the left bank population, the masses of lime-capsules (18.3 g/1000 pcs.) and seeds (11.9–12.7 g/1000 pcs.) have turned out to be noticeably less than in the right bank population (lime-capsules – 24.8–29.9 g/1000 pcs., seeds – 16.1–18.0 g/1000 pcs.). In the left bank population, up to 60 % of the lime-capsules have been seedless and up to 43 % of the seeds have been empty. Seed viability has been equal to 17–32 %.In the right bank population, most of the lime-capsules have contained seeds (up to 91 %), and the proportion of empty lime-capsules has been small (up to 18 %). Seed viability has been equal to 66–83 %. Field germination of the seeds has been equal to 9.2 % (for some trees – up to 10.5 %) in the left bank population and 12.2 % (up to 21.1 %) in the right bank population. Despite the low field germination of the seeds in both populations, it is possible to obtain seed planting stock for creating artificial plantings of T. nasczokinii in order to preserve and restore the population of this rare relict species in the south of Central Siberia.

Оценка секвестрационного потенциала осиново-березовых древостоев островных лесостепей Средней Сибири

The forest-steppes of Central Siberia occupying submontane troughs and intermountain basins separated by taiga vegetation are considered insular. Forest woody vegetation is mainly represented by birch, aspen, larch and pine stands. A decisive role in the ecological sustainability of forest areas is played by larch plantations. This study has aimed to identify the characteristics of the dynamics of individual forest elements in the mixed deciduous stands within the forest area. The tasks have been to identify the characteristics of the forest area, characterize the dynamics of the taxation parameters of major and minor elements of the mixed stands and assess the contribution of the stands to the carbon balance. The work is based on the data of 548 strata. We have established the characteristics of the forest area age structure and how the stands of various completeness and productivity are represented in it. We have also estimated the variability of the average stands taxation parameters in different age periods. The average values obtained have become the basis for mathematical modeling of the table of the dynamics of the taxation parameters of the mixed stands. It turns out that the process to a reasonable degree of adequacy is reflected by the Weibull distribution. The accuracy of the equations has been estimated by the value of the coefficient of determination (R2) and the standard error of the equation (S). On the basis of the obtained mathematical models, we have constructed the table of the dynamics of the average taxation parameters of the stands of the forest elements and of the mixed stand as a whole. The biological system of forest woody vegetation under consideration has a significant carbon sequestration potential. However, there is currently no generally accepted procedure for assessing the effectiveness of this process. Russian and foreign researchers have collected a large amount of data from different regions, but they have been using different methods. To estimate carbon stocks in the stands that are the object of the study, we have used the conversion-volume method for estimating carbon stocks in forest plantations. The result is the obtained data illustrating the dynamics of carbon stocks in the aspen-birch stands in the insular forest-steppes of Central Siberia.