Home – Home – Jornals – Contemporary Problems of Ecology 2024 number 4

An analysis of the ecological characteristics of cyanobacteria in Svalbard has been carried out. Two groups of habitats have been identified: aquatic and terrestrial. The main factor determining the development of cyanobacteria is considered to be the degree of water saturation. The variability of habitats can be represented as a gradient of moisture from typically aquatic to dry terrestrial habitats. Based on the number of findings and species richness, it can be concluded that the most favorable habitats for cyanobacteria in Svalbard are 1) rocky communities in conditions of sufficient moisture, 2) exposed soil surfaces on which biological soil crusts form, 3) slow, well-warmed streams, and 4) specific over-moistened habitats such as seepages. Using the example of the analysis of the ecological characteristics of species growing in the archipelago, it is shown that the concept of eurybiont properties of cyanobacteria is not tenable. The greatest plasticity is exhibited by Nostoc commune Vauch. ex Born. et Flah., Microcoleus autumnalis (Trev. ex Gom.) Strunecky et al., Calothrix parietina Thur. ex Born. et Flah., Oscillatoria tenuis C. Ag. ex Gom., Pseudanabaena frigida (Fritsch) Anagn. All of cyanobacterial species, including those mentioned above, have obvious ecological preferences. Analysis of the substrate specificity of cyanobacteria demonstrates that the greatest number of species are found in soil, rocky substrates, and moss-like environments.

A comprehensive paleoecological study of permafrost peat deposits from three locations of the middle reaches of the Yuribey River in the subzone of modern subarctic shrub tundra of the Yamal Peninsula has been carried out. Based on the results of palynological and carpological methods and radiocarbon dating data, the changes in regional and local vegetation and climatic conditions of Central Yamal in the Late Glacial and Postglacial periods are reconstructed. It was found that in this area shrubby tundra with Betula nana were widespread in climatic conditions close to modern ones in the Younger Dryas about 12.6-11.7 cal. ka BP. The penetration of tree species (Betula sect. Betula, Picea obovata, Larix sibirica) and their accompanying boreal herbaceous plants began due to improved climatic conditions in the Early Holocene warming about 10.2-9.7 cal. ka BP. The most favorable conditions for the growth of tree-shaped birch, larch and spruce in the territory of Central Yamal existed in the Early and Middle Holocene in the range of 10.2-4.4 cal. ka BP. At that time, sparse woodlands or even closed forests were common, the climate was much warmer than the modern one. Forest vegetation degraded and open landscapes with tundra communities formed at the end of the Middle Holocene (4.5-4.4 cal. ka BP). The climatic conditions have become close to modern ones.

The paper examines the influence of several fire characteristics including fire energy release, seasonality and duration on the number of wildfires resulting in tree stands mortality in Siberia between 2002 and 2022. Fire energy release was assessed using Fire Radiative Power (FRP), measured using MODIS data. To assess the degree of forest stands disturbance and to identify fires resulted in the forest stand mortality, a global forest cover change product generated from Landsat satellite data was used. Siberia experienced an increase in both total burned area and the area of stand replacing fires between 2002 and 2022. At the same time, an increase in the fire radiative power was also observed. The total values of fire radiative power for stand replacing fires (390.2 (σ = 80.5) MW/km²) were significantly higher ( p < 0.01) comparing to fires that did not result in the tree stands mortality (291.8 (σ = 74.7) MW/km²). Fire radiative power in dark coniferous forests was 20-25% higher comparing to FRP in mixed forests with a predominance of deciduous stands. Stand replacing fires were mainly observed in the late summer with the peak occurring in July - first half of August, while non-stand replacing fires were observed throughout the entire fire season. Stand replacing fires were also characterized by a longer duration (average duration 4.8 (σ = 1.0) days) compared to non-stand replacing fires (3.9 (σ = 0.7) days).

The questions of changes in the life status of Larix gmelinii along the gradient of urbanized ecotypes are considered on the basis of population analysis and morphometric approach. L. gmelinii growing under different conditions differed in a number of size and growth characteristics of photosynthetic activity. The maximum values were noted in plants growing in public gardens and on city streets under conditions of high insolation. The vitality structure of the populations of the species in the vegetative ontogenetic state changed from depressive to equilibrium, the population quality index changed from 0.2 to 0.333. When examining the landscaping of transport highways of the city, local populations of L. gmelinii in the generative ontogenetic state were of a prosperous type, the population quality index varied slightly from 0.47 to 0.49. The plasticity of the species, the high viability of L. gmelinii, due to resistance to air pollution, unpretentiousness to soil conditions of growth, transplantation, allow larch to be widely used for landscaping urban areas.

The results of studies of bottom biocenoses in three types of littoral zone (rocky biotope, gravel-sand biotope and surf zone with thickets of higher aquatic vegetation) of Lake Onego in 2013 and 2014 are presented. Our results show that among the three types of coastal zone, the maximum values of macrozoobenthos biomass were noted in the rocky littoral zone (3.4-6.6 g/m²), the minimum values in the sandy zone (0.1-0.2 g/m²). The invasive species Gmelinoides fasciatus (Stebbing 1899) (CRUSTACEA: AMPHIPODA) has successfully naturalized in all types of littoral zones of the reservoir in recent decades. On the rocky type of biotope, G. fasciatus dominates both in numbers and biomass.

This study is focused on soil nematode communities in under-crown areas of tree plants introduced to and cultivated for a long time in the botanical garden on Is. Bolshoy Solovetsky (Arkhangelsk Region, Russia). Soil nematode communities of natural forests (pine-, spruce-, birch stands) were studied as the control. The study has demonstrated that the taxonomic diversity and abundance of nematodes, as well as the share of plant parasites in the trophic structure of nematode communities in the soil under introduced trees were higher compared to natural forests. The ecological indices (structure index SI, enrichment index EI) changed non-uniformly and so had poor performance as tools for evaluating the consequences of the plant introductions for the soil ecosystem. Correlation analysis revealed a significant positive relationship between the content of carbon and nitrogen in soil and the absolute and relative abundance and the taxonomic diversity of plant parasites, as well as a significant negative relationships between C: N and fungal feeders, also between the soil pH and the taxonomic diversity of nematodes and the relative abundance of bacterial feeders and EI. The entomopathogenic nematode Steinernema affine Bovien revealed on the island has been reported for the first time in Russia.

For the first time, information is provided about the algae of Lake Azas, part of the water area of which belongs to the Azas State Nature Reserve. 171 species and intraspecific taxa have been identified, which belong to 72 genera, 50 families and 8 divisions. It has been established that the basis of the algal flora consists of diatoms and blue-green algae. 14 dominants were identified, 9 of which belong to the Bacillariophyta department. An ecological and geographical analysis of algae in the reserved part of the lake was carried out. It was established that the algal flora of the water body is represented by benthic species with a predominance of indifferent forms in relation to the algae and active reaction of the environment. In all studied biotopes, 123 species were identified - indicators of water saprobity. The predominance of betamezosaprobionts and oligosaprobionts was noted. Geographically, cosmopolitan and boreal species dominated.

In pine and birch-aspen forests that are typical for forest-steppe Ob region in Novosibirsk area we conducted a study of earthworm populations (Lumbricidae) with taking into account forest mosaic. A detailed analysis of the structure of earthworm complexes made it possible to identify concrete species and living forms that are biotopically distributed to both a certain type of forest and a forest microsite. Asian species mainly predominate in pine forests, cosmopolitans in birch-aspen forests. Differences in the population of forest microsites in terms of earthworm population density and biomass are more pronounced in the forest gaps than in the spaces under tree crown and between tree crown, especially in pine forests. Studying the population of earthworms in the deadwood we revealed the characteristic features of complexes structure for each type of forest: in pine forests incomplete deadwood earthworm complexes complement soil ones, in birch-aspen forests, deadwood is a specific microsite with a full-complete earthworm complex.

The ¹³C-NMR spectra and elemental composition of lipids of gray forest soils (Greyic Phaeozems), dispersed carbonate chernozems (Haplic Chernozem Hypocalcic) and chestnut soils (Kastanazems) of Western Transbaikalia were determined. The contribution of carbon contained in lipids to the total reserves of organic carbon is calculated. For the first time, the work presents the characteristics of the lipid fraction of organic matter in cold soils of Western Transbaikalia. An analysis of the spectra was carried out, including the assignment of signals from ethoxy groups, phenol derivatives and alkene fragments, as well as an indication of the ranges of chemical shifts characteristic of certain types of carbon nuclei. A comparison was made of the content of various types of structural elements in the studied lipids. The results obtained showed that the main part of lipids consists of esters and fatty acids. Carbon atoms in the molecular structure of lipids are predominantly represented by aliphatic chains. Analysis of the composition of lipids showed that the content of carbon atoms is 65-73 %, and hydrogen - 8-10 %. The high concentration of oxygen atoms in lipids indicates that functional groups containing oxygen are concentrated in the aliphatic part of the lipids. The share of lipid carbon in the total reserve of organic carbon is 6.5 % for chestnut soils, 5.8 % for gray forest soils, 4.1 % for dispersed carbonate chernozems.

The abundance and morphogenetic indicators of the Adonis villosa Ledeb., a vulnerable species in the Altai Republic (AR), have been studied. For the first time, genetic differentiation in six cenopopulations (CP) of A. villosa using ISSR markers and variability of morphometric characters in individuals from four CPs in the AR were revealed. Similarities in the variability of morphometric characters in the studied CPs were revealed, as well as a decrease in the number of mature generative individuals by 1.5-14.0 times over the period from 2017 to 2023. The genetic structure was studied using 6 primers: M 9, UBC 834, UBC 830, UBC 857, UBC 840, UBC 811. Of these, UBC-857 turned out to be the most informative. In representatives of the six studied CPs, we identified four variants in the distribution of ISSR markers, and a high similarity in the distribution of ISSR markers between the A. villosa CPs (88-99 %) was found. Intrapopulation similarity among individuals of this species is also high and reached 97 %. The probable reasons for this phenomenon are the small number of mature generative individuals in the CP (no more than 10) and their spatial isolation. In Northern Altai, A. villosa individuals have a homogeneous genetic structure, which leads to the vulnerability of this species. This species requires a special approach to conservation in natural conditions and culture.

Trophic relationships of bats (Chiroptera) with Lake Baikal biota were assessed based on microscopic studies Myotis petax feces (n=22). From 82 to 86 % of samples maintained fragments of exoskeletons of caddis flies (Trichoptera) and dipterans (Diptera). These taxa include mainly aquatic and semi-aquatic species. Many species from these taxa are endemic to Lake Baikal. Terrestrial insects were found in studied samples less frequently (Hymenoptera - 41 %, Neuroptera - 27 %, Heteroptera - 9 %). The morphological analysis revealed fragments of Baikal amphipods in two fecal samples of M. pretax. Further molecular studies will allow the detection of greater invertebrate taxa diversity in fecal samples of bats feeding near Lake Baikal.