Home – Home – Jornals – Contemporary Problems of Ecology 2021 number 3

The considered methods of ecological-geographical analysis of vegetation, indicated within the framework of the method of diversity, make it possible to identify the main botanical-geographical relationships, to determine the dynamic processes of vegetation. These methods can be used at different structural levels of vegetation - global, regional, landscape and even cenotic.

A 115 cm long section of lacustrine-wetland sediments from Langou I Bay (Eastern Primorye; 44°25′10,16′′, 135°54′26,08′′) has been studied. According to the developed age model, the age of the deposits was 3900 years. We performed a multi-proxy study using the methods of geochemical, chironomid, diatom, and palynological analyzes. Our investigation has shown that the development of climatic and ecological conditions on the coast of the Eastern Primorye in many respects developed synchronously with the climatic phases known for the late Holocene. Period from about 4200 to 2600 cal years BP corresponded to the first and second warm of the Japanese Jomon stages and the late Jomon transgression. The peak of summer temperatures in the area took place between 2900 and 2600 cal years BP. Cooling after 2600 cal years BP was less pronounced than in Japan (Jomon and Kofun cold stages). The reconstructed temperatures were 1 °C lower than today, while in Japan the temperatures were 2-3 °C lower than in modern time. The Medieval Climatic Optimum (Nara-Heian-Kamakura stage in Japan) was reconstructed for Eastern Primorye from 1250 to 750 cal years BP. During this period the climate was humid with summer temperatures about 1,5 °C higher than in modern time. The period between 750 and 250 cal years BP could be associated with the Little Ice Age and was characterized by a decrease in summer temperatures by 1,5-2 °C below modern level. The last 200 years have been marked by shallowing of the lake to an almost complete drying out. This period is characterized by temperature fluctuations and a warming trend.

Combination of steppe and tundra locations at the Altai highland depressions - Bertek and Khindiktig-Khol’ - is considered with regard to the hypothesis verification of steppe-tundra existence in northern Eurasia during the Last Glacial Maximum and its contemporary landscape analogues. Data on soil-vegetation cover diversity at the Altai highland depressions are represented. Cause-and-effect relations explaining spatial differentiation of nature complexes are identified. Thermal regime of locations with the predominance of steppe and dwarf birch vegetation is investigated. Interrelation between soil-vegetation cover differentiation and distinction in microclimate and permafrost boundary are proved.

A structural and rhythmological analysis of shoot systems of three Atraphaxis species was carried out. The species demonstrate differences in the structure of terminal synflorescences, floral units, and generative shoots. The duration of spring-summer blossoming of Atraphaxis is determined by the number and branching order of paracladia in synflorescence and the length of generative shoots. The species differ in the morphological differentiation of the axes and in the distribution of functions between generative and vegetative shoots. In A. frutescens , the main skeletal axes are built on the basis of generative shoots, which perform both the assimilative and reproductive functions. This species takes the life form of aeroxylic shrub, dwarf shrub or semi-shrub, depending on the preserved part of vegetative zone of generative shoots, which is determined by wintering conditions. In A. replicata , the main skeletal axes are formed on the basis of both generative and vegetative shoots. Terminal abbreviation, that is, underdevelopment of terminal synflorescence in powerful generative shoots, creates conditions for the transfer of reproductive function to small early blooming generative shoots, which allows the species to adapt to semiarid climate. In A. pyrifolia , the formation of a perennial axial system on the basis of powerful branched vegetative shoots makes it possible to more fully realize the advantages of acrotonic branching and to achieve a significant size. The specialization of generative shoots in the performance of the reproductive function is realized most fully in this species.

The variability of metric characters of three species of the genus Nitraria ( N. schoberi L., N. sibirica Pall., N. komarovii Iljin & Lava ex Bobrov) in 20 populations of Kazakhstan was studied. It was found that N. sibirica differs from N. schoberi and N. komarovii in small leaves, fruits and seeds, and in the structural features of the inflorescence and flower. N. sibirica is characterized by a larger number of flowers per inflorescence (on average 25-66 pcs.), Compared to N. schoberi and N. komarovii (on average, 14-28 pcs.). N. sibirica also differs from N. schoberi in narrow corolla petals (1.3 times), small anthers (1.46 times in length and 1.2 times in width) and pistils (1.25 times in length and 1.44 times wide). N. komarovii differs from N. schoberi in narrow leaves (1.7 times). N. komarovii has relatively large anthers, especially in width, which, together with smaller corolla petals, distinguishes this species in flowering - N. komarovii flowers look bright yellow, while in N. schoberi they are white, in N. sibirica they are light purple. N. komarovii fruits are orange, pale or bright red. In N. schoberi , fruits are dark-bordered, in N. sibirica , they are black. At the intraspecific level, the stability of most of the metric characters and their independence, except for the habitus of N. sibirica plants, from the 16 studied climatic parameters of the habitats were revealed. At the same time, a number of morphological features were revealed in N. sibirica plants in populations from the Ili Basin. In these populations, N. sibirica plants form bushes up to 1.8 m tall, with a large number of flowers per inflorescence (up to 90 pcs.), Large corolla petals (on average 3.5 mm long; 2.2 mm wide), small anthers (about 0.6 mm), small fruits (5-5.5 mm long) and small (about 4 mm long) narrow ovate bones. These features indicate the ecological-geographical differentiation of N. sibirica under the extra-arid conditions of the stony desert of the basin, and testify in favor of a separate taxonomic rank of these populations.

As a model species to study the geographic variation of cold hardiness in insects, we used ants Lasius flavus from the populations in the regions separated by thousands of kilometers (southern Finland, Moscow Region, Amur Province) with contrasting climates - from maritime variants to those, differing in the degree of continentality. We measured the temperatures of maximal supercooling ( SCP ) as well as the limits of tolerated negative temperatures ( LT _{50 %}), and evaluated the overwintering conditions. The data on L. flavus were compared to similar data obtained on L. niger , аs well as to similar measurements in separate nests of L. alienus , L. psammophilus and L. fuliginosus , which were published earlier. The workers of L. flavus and L. niger have close values of cold hardiness ( LT _{50 %} -13 to -15 °C, minimal average SCP -24 to -25 °C), although these species inhabit different climatic zones and place their overwintering chambers at a different depth. Such resistance to long-term exposure to negative temperatures is more than sufficient even for overwintering in the coldest of the studied areas (Arkhara village, Amur Province), where the average minimal temperature in January in the ant overwintering chambers at 50 cm of depth does not fall below -6 °C. The variation of cold hardiness and higher values of its parameters, in other studied ant species is due to their insufficient preparation for overwintering. However, the narrow range of SCP (-27 to -29 °C) in the most cold resistant individuals of all studied species allows to confidently assume that their average Т _p and threshold LT _{50 %} correspond to those of L. flavus and L. niger. Similar (or maybe identical) cold hardiness of the studied ant species appears to be a stable trait of the genus Lasius , as was demonstrated for another ant genus, Myrmica , and as opposed to the genus Formica , where different species have individual characteristics of cold resistance. Such cold hardiness that is excessive for overwintering in warmer climate (southern Finland, Estonia) appears to have no adaptive value. It can be considered as a byproduct of the diapause, which is manifested in preadaptation to withstand negative temperature. However, it was this cold hardiness that made possible the colonization of the giant territory of the southern Siberia and Far East by the discussed ant species.

The estimation of the contrast the physical and chemical properties and carbon losses of pyrogenic peat soils is given 20 years after the large fire in a swamp spruce forest ( Picea obovata Ledeb.) located in the valley complexes of small rivers of the Kuznetsk Alatau (Khakassia Republic). The area of the fire at present occupied by shrub-sedge-green moss birch forest ( Betula pubescens Ehrh.), belonging to the group of short-term-derived postfire grass forests. Pyrogenic peat soils (mechanical and chemical underburning) formed due to passive smoldering - thermal effects below the point of ignition, are characterize by a high variation of physical and chemical parameters ( Cv 26-37 %). Using the methods of multidimensional statistical analysis (cluster, discriminant, canonical), four clusters were formed that identify pyrogenic series of peat soils. In the total contribution of chemical indicators to the differentiation of clusters, the largest proportion belongs to organic carbon (83 %), and a much smaller proportion belongs to moisture of peat soil bulk (15 %). Based on the diversity and abundance of fire traces in the profile of pyrogenic peat soils, we conditionally associate them with the effect of light, moderate, medium and high fire severity. In proportion to the fire severity, pyrogenic series of peat soils are 1.6-2.7 times enriched with ash components, the content of which ranges from 18.9 to 77 %, are 2.2-4.3 times compacted - the bulk density reaches 0.147-0.421 g/cm³, the pH value is consistently shifted from 6.8 to 7.6. A new approach is proposed to estimating carbon losses in the process of passive peat smoldering by the difference in the content before and after a fire, which complements the traditional method of accounting by the depth of burning of the peat layer. In the 0-20 cm layer of the pyrogenic peat soils, additional carbon losses range from 1.6 to 4.0 kg/m², which is equivalent to 5.9-14.8 kg/m² of CO₂ emission. Data about the additional loss of carbon at the stage of passive smoldering of the peat substrate are provide for the first time.

The paper provides a review of the current state of research in the field of biotesting. Authors discuss the problems of environmental studies and ways to solve them. The basic principles and examples of the use of enzymes for the detection of toxicants in various environmental samples are considered. Based on the analysis of numerous published data, the advantages and limitations, as well as the prospects for using enzymes for performing biotesting tasks, are estimated. A separate section of the review is devoted to bioluminescent enzymatic bioassays developed by the authors. These bioassays are successfully implemented for environmental monitoring of water, soil, and air. The necessity of developing a battery of enzymatic bioassays is substantiated. It allows to have the most complete and accurate information about the levels of environmental pollution.

Vegetation survey of the three model sites was conducted on lime-stone plateau Emdy in Mangyshlak middle desert subzone on eastern shore of Kaspian sea (Western Kazakhstan). The main aim was to find indicator species in vegetation composition which reflect ancient anthropogenic influence about 1500 years ago. Model sites are situated in comparable ecological conditions and differ only by the type and time of the anthropogenic influence. One situated in area of the ancient settlement III-V centuries; second one was in the area of probable former agriculture and third one used as a control nearly without any anthropogenic influence. It was found that in plant community structure four main synusia could be determined. The most diverse synusia of the desert ephemeras contains 61 % of the plant species pool and may be considered as an indicator of former anthropogenic activity. There were no any specific plants connected with former agriculture on the second site. Considering this fact together with general ecological conditions of the site it was concluded that there were no any former agriculture on this site. It was shown that different ephemeral species react on such microhabitat characteristics as humidity, insolation, salinization and soil bioturbations. All ephemeral species could be divided on true and induced ephemera. Last group consists of widespread ruderal annual mesophytes ( Buglossoides arvensis и Descurainia sophia ). These species appeared in places of long and intense anthropogenic pressure and are able to persist in plant communities at least up to 1500 years after the end of the anthropogenic pressure.