Home – Home – Jornals – Contemporary Problems of Ecology 2023 number 2

In the study, the first data on the distribution of cyanobacterial toxins were obtained and, for the first time, a molecular genetic determination of cyanotoxin producers in the plankton of some lakes in the permafrost zone in Yakutia was carried out. Most of the lakes were characterized by high concentrations of nitrogen, phosphorus, chlorophyll a and an increased content of organic matter, which could be associated with a high anthropogenic load. During the summer period, water blooms were visually observed in three of the six studied lakes. The abundance and biomass of cyanobacteria in the lakes varied within 13.7-676.3 million cells/l and 0.6-4.8 mg/l, respectively. Eight species of potentially toxigenic cyanobacteria were found in phytoplankton using light microscopy. In environmental DNA isolated from planktonic samples, regions of the mcyE gene involved in the biosynthesis of microcystin were amplified using the polymerase chain reaction method. During the study period, cyanobacteria capable of producing neurotoxic anatoxin-a, saxitoxins, and hepatotoxic nodularins were absent in the lakes. Using genus-specific primers to the mcyE gene, it was found that species of the genus Microcystis were the main producers of microcystins in most of the lakes; and species of Dolichospermum - only in one of the lakes. Up to 8 structural variants of microcystins, in general arginine-containing isoforms MC-LR, MC-RR, MC-YR, MC-LY, MC-HIlR, [Asp³]MC-LR, [Asp³]MC-RR, [Asp³]MC-YR, were identified in lake plankton using liquid chromatography-mass spectrometry. The maximum concentration of microcystins in plankton (intracellular fraction, 803 ng/l) was recorded in a sample from Lake Ytyk-Kel. The calculated content of microcystins per unit biomass of producing cyanobacteria (toxin quota) was low (0.005-0.069 µg/mg). In order to assess the potential hazard of toxigenic species of cyanobacteria to human health, the distribution of cyanotoxins and their producers should be further studied in water bodies of the region.

For the first time the diatom complexes were investigated in the upper part of bottom sediments in the freshwater lakes Cheko and Zapovednoye, located in the taiga zone of the south of Evenkia on the territory of the Tungussky state reserve. There were found and identified 156 diatom taxa in two lakes, and their ecological preferences have been determinate. In the Lake Cheko the valves of Aneumastus tusculus (Ehrenberg) D. G. Mann & A. J. Stickle was identified - this diatom officially described as a fossil. In the both lakes the similarities and differences in the diatom complexes have been revealed - it seems that the diatom complex of both lakes is similar to that for freshwater bodies of the world located at close latitudes in the taiga zone. Lake Cheko is distinguished by a smaller proportion of planktonic species, which is probably due to the greater flow of this lake. Also there is shown the dependence of the species composition of diatoms on the meteorological parameters of the environment (temperature and precipitation).

The article presents an estimate of methane emission in palsa mire in the European North-East of Russia based on the results of measurements by the method of static chambers and eddy covariance during the growing season. Hollows make the main contribution to the ecosystem flux, the rate of methane emission per season on these relief elements averaged 5,7 mg/(m²∙h) and was controlled by soil temperature and groundwater level. The methane emission on the ridges and the peat mound was noticeably lower and corresponded to 0,85 and 0,28 mg/(m²∙h). On the peat mound, the methane flux depended on the thickness, temperature, and humidity of the active peat layer. The cumulative ecosystem flux of methane into the atmosphere in May-September, obtained by the method of chambers and eddy covariance, corresponded to 9,5 and 11,4 g/m².

А 36-year study of bird number dynamics (1984-2020) on permanent accounting routes from the coast of Lake Baikal to the Barguzin Range highlands (460-1700 m s. l.) were performed. A steady decrease in the total abundance of background bird species after 1997-1998 was revealed. The resulting long-term series (as the example of model groups of birds) made it possible to identify the responses of the biota on climatic changes in the Lake Baikal region. Periods of high and low numbers in bird`s populations are probably associated with the passage of a wet and arid phases of a climatic cycle. In 8 background species (16.0 %), positive trends of long-term changes in abundance were revealed, and in 18 species (36.0 %), a steady decrease in abundance was established. Negative trends in population changes in distant migrants prevail over growth trends (11 species against 3 with positive trends). Some mechanisms of the formation of the local bird`s population are disclosed, including using the redistribution of the nesting species density between the river valleys and habitats at the high-altitude profile. Current long-term climate change in the region has a positive impact on changes in the abundance of background bird species in the highlands compared to the underlying mountain forest belt.

After results of autumn counts of waterfowl in the Selenga delta in 2018-2020, their recent numbers during the autumn migration were estimated, and its comparison to results of analogous intensive censuses in 1989-1995 was carried out. The decreasing of numbers and percentages was found in some duck species (Northern Pintail, Eurasian Wigeon, Northern Shoveler, and Pochard); these parameters are rather stable in Mallard. Data on stopover longevity obtained in other regions of the world in the last time let us to give more precise retrospective estimates for numbers of waterfowl having visited the Selenga delta during autumn migrations in the 2nd half of 1980s and the 1st half of 1990s. More adequate numbers of stopping birds in the period mentioned above are 0.5-1.1 million individuals per season (at least, not less) instead 2-5 million being proposed formerly. In the present time, the lower number limit for ducks having visited the delta per autumn season obviously appears to be 0.3 million individuals; intensive counts during all autumn migration are necessary to set the upper limit. Numbers of waterfowl are approximately twice less now than 30-35 years ago. Causes of their decrease need to be sought outside the Selenga delta, probably in the general situation in regional and trans-regional geographical populations. The delta prolongs to support more than 1 % of the East Asian geographical population of Pochard, which recently got the status “Vulnerable” in the IUCN Red List. The nature refuge “Kabansky” plays the much important role as the no-take zone for waterbirds during autumn hunting seasons.

The Neuroptera of the pine Tanaika Forest in the Republic of Tatarstan were studied using five beer-and-sugar bait crown traps operated continuously from 30 April to 1 October, 2021. The chrysopids Apertochrysa prasina and Chrysotropia ciliata clearly dominate among 1043 collected specimens (17 species). The number of species stenotopic for pines (Chrysopa dorsalis and Wesmaelius concinnus) is very low. The large number of Chrysopidae in this forest, normally characteristic of a deciduous forest, and the rarity of species characteristic of pines, can be explained by the fact that the traps mainly attract Neuroptera that feed at imaginal stage on pollen and honeydews, whereas almost all species characteristic of pines are predators. In addition, the traps on pine trees were located at a relatively low height (4-5 m from the ground), and so they attracted more specimens from the nearest deciduous trees and deciduous undergrowth than from pines, whose canopies are located much higher. Eleven species of Neuroptera are recorded from the Republic of Tatarstan for the first time; thirty-two species are now known from the region.

The rhythm of development, seasonal dynamics of photosynthetic pigment content, specific leaf area (SLA), water content, and the rate of accumulation of dry matter in D. octopetala leaves of spring and autumn generations under introduction conditions were studied. The obtained results were compared with similar indicators in the natural habitat according to the literature data. It was found that the restructuring at the cellular-tissue level led to an increase in the specific leaf area by 3.7-4 times. The leaves of the spring generation have increased the life span, the duration of vegetation, the amount of chlorophylls and carotenoids. In the leaves of the autumn generation, these indicators have not changed. The leaves of the spring and autumn generations contained 7.89 mg∙g^-1 and 3.32-6.48 mg∙g^-1 of chlorophyll, respectively. The structural and functional characteristics of the pigment apparatus of the leaves of spring generation corresponded to the high intensity of photosynthesis, the autumn - low intensity. Under the conditions of introduction, the former showed ecological plasticity and a high ability to acclimation changes, the latter - a conservative, stenobiont adaptation strategy. The growth rates of D. octopetala remained at the characteristic level for the species. The number and mass of diaspores per flower, the length of peduncles increased by 2.2 and 2.8 times, respectively. Germination over the entire observation period was low, 2.32 ± 0.7 % over a six-year observation period.

Changes in the seasonal development of lilac species in the collection of the South Ural Botanical Garden-Institute (Ufa, Russia) are analyzed according to data for 2005-2010 and 2015-2020. The objects of research were 11 species of lilacs that have reached the generative phase; all types of lilacs are grown from seeds obtained from other botanical gardens in the 50-60s. last century. Phenological observations of lilac species are carried out annually in 9 phenological phases. The onset of the initial (opening of the buds and the beginning of the growth of shoots) and the final (leaf fall) phases of the growing season largely depends on the weather conditions of a particular year. At the same time, the role of species (genetic) features at the beginning of seasonal development is insignificant (species begin to vegetate together), while, starting from the flowering phenophase until the end of the growing season, this role increases significantly. The significance of interannual differences in the middle of the growing season fades into the background. Such characteristics of development phenorhythms as the duration of flowering and the duration of the growing season continue to be dependent on fluctuations in weather conditions in different years. The sequence of the passage of phenophases by different species from year to year is preserved. Compared with the first decade of the 21st century, in the second decade, the start of the growing season became later (by 4 days on average), and the end of the growing season became earlier (by 8 days on average); the timing of the beginning of flowering also shifted by 4 days on average towards late dates. The duration of flowering of lilac species in 2015-2020 decreased by 5-6 days compared to the period of 2005-2010. The duration of the growing season was reduced by 12 days on average. All these phenomena are caused, obviously, with changes in the climatic parameters of the Bashkir Cis-Urals.

The study of the effect of biotic and abiotic factors on the duration of development of the gypsy moth (Lymantria dispar (L.)) and the establishment of thresholds for the development of stages in individuals of the West Siberian population of different latitudinal origin (56°33′ N., 76°37′ E.) (northern part of the range) and (53°44’ N,78°02’ E) (central part of the range) was carried out. We analyzed possible ways to accelerate the development of individuals of this species in the northern part of the range - reducing the number of instars, increasing the developmental rate of instars without reducing their number and lowering the development thresholds. It was found that the reduction in the number of larval instars is not a significant factor of the analyzed effect in this population. The threshold of late embryonic development in the West Siberian population is significantly lower than that defined for populations of the European part of Russia, a lower threshold for the development of individuals in the northern part of the population with a low sum of effective temperatures (SET) of early embryonic development is noted. The SET of early embryonic development has a significant impact on the acceleration of the development of active stages on the northern border of the area, and the smaller it is, the higher the impact. The high plasticity of the adaptation of the species to temperature conditions allows the gypsy moth to become established in new, more northern regions. This plasticity is provided both by natural selection and reduction of threshold temperatures of development, and by epigenetic mechanisms that allow adjusting the rate of development depending on the temperature conditions of the habitat.

The processes of biodeterioration of the unique monument of rock art in Western Siberia “Tomskaya Pisanitsa” were studied by complex of biological and mineralogical methods. The species composition of the lithobiotic community (bacteria, fungi, and lichens) was identified using a complex of cultural, morphological, and molecular genetic methods. It is shown that the destruction of the monument is a result of interrelated physical, chemical and biological processes, accompanied by a change in the properties of the rock and its biological colonization. The structure of microbial communities depends on local environment and successional processes. The development of biofilms with the dominance of cyanobacteria was observed on the rock zones of increased moisture and the formation of carbonate crusts. The problems of adaptation of the lithobiotic microorganisms to existence at the rock art monument “Tomskaya Pisanitsa” as well as their role in the processes of oxalate and carbonate biomineralization are discussed. The obtained results point to the danger of deterioration of the “Tomskaya Pisanitsa” and indicate the need to find new effective ways to protect this monument taking into account the accumulated scientific data.