Home – Home – Jornals – Contemporary Problems of Ecology 2023 number 1

The unique ecosystem of Lake Baikal is made up of a diverse, mostly endemic fauna. The spongiofauna of the lake is represented by two families: endemic Lubomirskiidae and cosmopolitan Spongillidae. In recent years, the situation on Baikal has been characterized as catastrophic, especially when it comes to the littoral. There are numerous reports about the oppressed state of the Baikal sponges and the decrease in their numbers in many areas of the lake. The question is raised that not only nature protection, but also nature restoration measures are needed. The review discusses the basic techniques and methods of growing sponges. 4 main approaches to the cultivation of sponges ex situ and in situ are described in the most detail in world practice: 1) from larvae; 2) from primmorphs (sponge cell cultures); 3) from resting stages (gemmules and reduction bodies); 4) from explants (fragments of living tissue separated from the parent organism). The review discusses attempts to apply the described approaches used in world practice for growing Baikal sponges. Based on the analysis of the literature, it is assumed that the use of the most effective of the above approaches will make it possible to develop a technology for obtaining Baikal sponges.

In the last decade, mass death of endemic sponges has been observed in the coastal zone of Lake Baikal. This paper presents observations of the Baikal sponge fauna within the transects established throughout Baikal in 2015. Based on visual descriptions, the types of damage to Baikal sponges are characterized. A downward trend was revealed from 2015 to 2020 in the projective cover of the bottom with healthy sponges of various body shapes: encrusting - 3.6 times, branched - 2 times and globulous - 4 times. The reduction in the total area occupied by healthy and damaged sponges of various forms occurred more than 2 times, from 238 m² to 110 m².

Results of bird counts from 1880 to 2019 (intermittently, and mainly since 1960), averaged over the first half of the summer (16.05-15.07) were analyzed to identify the spatial-typological structure and organization of the corvid assemblage of Northern Eurasia. 352 researchers have been involved in collecting of this material over 110 years. Data processing was carried out using multivariate statistics methods, including cluster analysis and linear qualitative approximation of connection matrices, as well as gradient and expert approaches. As a result, the main territorial trends in corvid assemblage and the natural and anthropogenic regimes correlating with them have been identified, and the relationship between the spatial variability of the assemblage of these birds and the heterogeneity of habitats has been assessed. Quasifractal spatial differentiation of assemblage was shown. The analysis of corvid groups identified using factor classification gave an unsatisfactory result of approximating the spatial and typological variability of their assemblage in terms of abundance at the level of landscape tract type and a rather high information content of species classification by abundance in all 8144 habitats. A satisfactory explanation for the heterogeneity of corvid assemblage was achieved only after averaging the abundance indices over landscape groups. It was not possible to get an idea about them using cluster analysis, and only the use of gradient and expert (speculative) approaches, followed by an assessment of the information content of the representations, can be considered acceptable for obtaining such generalizations. The use of these techniques increased the assessment of the information content of representations by averaged abundance indicators by seven times in terms of explained variance and three times in terms of the multiple correlation coefficient. At the same time, structural classifications by species, and especially by territorial communities, acquire a two-dimensional reticular (network) form. The formalized classification of corvid species according to the similarity of distribution is seven, and the assemblage is almost twice as informative as expert-speculative representations.

Based on the results of winter bird surveys conducted in 70 habitats over 12 years, in the period from 1982 to 2002, a hierarchical classification and a structural graph of the similarity of ornithocomplexes of the southwestern plains of Western Siberia and Northern Kazakhstan were compiled. The hierarchical classification contains 3 types and 9 subtypes of the ornithocomplexes. The similarity graph (the spatial-typological structure of the ornithocomplexes) is constructed at the subtype level and is represented by three trends. The first, the most significant of these series is determined by the influence of urbanization, afforestation and partly by the development of the reed tier. The second series of territorial changes of ornithocomplexes is associated with changes in the built-up and anthropogenic feeding of residential habitats. The third row is formed under the influence of afforestation and overgrowth. The characteristics of ornithocomplexes subtypes are compared, which contain information on the three most numerous bird species (leaders in abundance), their share in the community, population density, as well as background species richness. Based on the assessment of the degree of coincidence of the similarity of ornithocomplexes and environmental factors, the hierarchy of the impact of the main anthropogenic and natural factors determining the formation of the winter bird population is established. Regional specifics and seasonal changes in the significance of environmental factors in the formation of winter ornithocomplexes of the Tobolo-Irtysh forest-steppe and steppe are established.

Climate changes entails an increase in the forests burning throughout the whole boreal zone. We have studied the long-term dynamics of fire rate and post-fire recovery of vegetation cover productivity in the pine forests of Central Siberia, and analyzed the dependences of the fire frequency and the burnt areas on climatic variables. Methodically, the work is based on a combined analysis of data from ground surveys, remote sensing (spectroradiometric and gravimetric surveys by Terra / MODIS and GRACE satellites), and coupled analysis of dendroecological data and environmental and climatic variables. The main impact on the fire frequency and burnt areas is due to the moistening conditions (total precipitation, soil moisture, aridity index scPDSI) in the period preceding the fire. The correlations of combustibility parameters with air temperature are lower than with humidification conditions. It is shown that soil moisture gravimetry data can be used in assessing the risk of forest fires. A decrease of fire Return intervals from 33 years to 20-25 years in the period from the 18th to the 20th century was revealed. In the second decade of the 21st century, both catastrophic (more than 1 million ha) forest fires and a significant increase in flammability were observed: the number of fires and the area of burnt areas increased, respectively, by 3.5 and 3.0 times. A high level of correlation has been determined between the growth index of pine trees and the vegetation cover productivity indices (gross (GPP) and net (NPP) productivity) generated from remote sensing data. The result obtained indicates the applicability of the indices in the studies of the forest stands productivity. Significant trends in flammability in the 21st century, both in terms of the frequency of fires and the areas covered by fire, have not been identified. The productivity of the vegetative cover on burnt areas, as well as the value of the index of radial increment of pine trees, quickly (within ~ a decade) recovers to pre-fire values, which indicates that northern pine forests retain their carbon-storing function under conditions of climate change and increased fire rate.

The results of the evaluation of the effect of experimentally dosed salinization and salinization with a simultaneous moderate increase in temperature on somatic indices, biochemical blood parameters and survival of perch Perca fluviatilis fingerlings are presented. The limit of salinity tolerance for perch fingerlings used in the experiment turned out to be a mineralization value of 8 g/l. An increase in temperature led to a decrease in the tolerance limit of perch fingerlings during salinization to 5.3 g/l. In conditions of elevated temperature and mineralization, maximum mortality was noted, the lowest values of the fatness coefficient and the hepatosomatic index of fish, indicating the depletion of experimental individuals, which was determined by the revealed violations of water homeostasis. An increase in energy costs with an increase in temperature is consistent with the data of an increase in the load on the excretory system of fish due to an increase in the permeability of fish tissues, which leads to a decrease in the content of basic inorganic ions in blood plasma. At background temperature, chronic exposure to increased mineralization also leads to depletion of the metabolic reserves of the fish body and the predominance of catabolic processes, which is confirmed by the low content of total protein and protein metabolism metabolites in blood plasma.

The results of studies of the dynamics of productivity, photosynthetically active radiation and evapotranspiration according to Terra Modis data for 5 test plots in the near-channel part of the floodplains of the Kargy river (a glycophyte, a swampy valley and a valley meadows), as well as willow thickets along the banks of the Mugur river, are presented. Analysis of long-term changes in meadow vegetation from 2000 to 2021 in the study area showed a general positive trend in gross productivity and differences between communities. Against the background of an increase in actual evapotranspiration (by 43 %), there is a decrease in potential (by 10 %), which indicated the drying up of the study area. Seasonal maxima of meadow productivity were observed in 2014, 2016 and 2020-2021. The years 2001, 2003-2004, and 2009 turned out to be critical for meadow vegetation. A weak positive correlation was found between the gross productivity of vegetation and the evapotranspiration of the territory, and a stronger one with photosynthetically active radiation. The seasonal dynamics of productivity corresponded to the meadow type of vegetation.

The reactions of leaves of balsam poplar (Populus balsamifera L.) on the impact of emissions of aluminum smelters were analyzed. The results of comparative analysis of mineral phase distribution on the surface of poplar leaves in the influence zone of Bratsk, Irkutsk, Sayanogorsk, Krasnoyarsk and Novokuznetsk aluminum smelters are presented. Newly formed minerals similar in composition to fluorite and gypsum were found in stomata of poplar leaves. Calcite crystals were found in large quantities in the conductive system of leaves. The formation of a biogeochemical calcium barrier in the stomata of poplar leaves, through which the neutralization of fluorine and sulfur compounds into inert minerals is assumed.