Privolzhskaya Upland Research Articles

Occurrence of the golden jackal (Mammalia, Caninae, Canis aureus Linnaeus, 1758) in the Saratov region, expansion of its range in the region against the background of its expansion in Europe and Russia

The history of golden jackal dispersal in Russia and adjacent countries, as well as in southern, central, eastern and northern Europe, is considered. Data confirming the demographic explosion of this species on the European continent territory are given. Materials on the dispersal of golden jackals in the European Russia are considered in more detail. The main emphasis is made on the study of the process of golden jackal penetration into the territory of Saratov region, from its first sightings in the Saratov Volga region in the late 1980s – early 1990s in the Dyakovsky (Saltovsky) forest to dispersal in adjacent territories. The penetration of the species into the Saratov Right Bank and its further dispersal throughout the region on both banks of the Volga river is described. It is shown that the areas of the modern jackal range are approximately the same both in the Right Volga Bank and Left Volga Bank of the Saratov region. However, the number of jackal is currently higher in the areas of the region located on the right bank of the Volga river. Probably, this is explained by more favorable conditions for the golden jackal habitat in this part of the region, associated with its higher afforestation. Gold en jackals breed in the southern districts of the Saratov region, located on both banks of the Volga river. However, golden jackals are also found in the northernmost parts of the region, and most likely there, as well as in the south of the region, its stable reproductively active groups appear. In the Saratov Volga region, in spite of its very low forest cover, the golden jackal is recorded both in the south-eastern and north-eastern areas, but its numbers are high enough only in the vicinity of the forest on the Prieruslan sands and in areas along the Volga river, where there are areas of floodplain and bairn forests. In the Right Volga Bank of the Saratov region the golden jackal is most abundant in upland oak forests of the Privolzhskaya Upland, occurs in floodplain forests of the Medveditsa river and in the Medveditsa–Khopyor interfluve.

Morphometric and hydrological features of the lakes of the Sergachsky municipal district (Nizhny Novgorod region, Russia)

The article presents the results of a study of the morphometric and hydrological features of the lakes of the Sergachsky municipal district (Nizhny Novgorod region, Russia), lying in the north of the Privolzhskaya upland. A bathymetric survey was carried out on the lakes of the researched territory from the board of an inflatable boat, using an echo sounder, combined with a navigator. The results of the field research were processed using the geographic information program QGIS, digital models of the relief of the six researched lakes were created, and their main morphometric and hydrological characteristics were calculated. Based on the analysis of the morphometric characteristics of the lakes and data on the landscape features of their surroundings, conclusions were drawn about the origin of the lake basins. Two genetic groups of lakes within the researched area are identified: karst and riverbed (oxbow lake).

Qualitative and quantitative parameters of the dynamics of the steering network of elementary watercourses in the northern forest-steppe in the XXI century (on the example of the catchment basin of the Ketarsha river, Privolzhskaya upland, Russia)

The article presents the results of researching the dynamics of the length of the channel network of elementary watercourses in the north of the forest-steppe zone in the XXI century. The research was conducted on the territory of the catchment basin of the Ketarsha River of the Privolzhskaya Upland, characterized by a high degree of anthropogenic transformation. The research is based on the materials of the expedition work, carried out in the summer of 2023, the results of geoinformation analysis of remote sensing data, topographic maps and literary sources. The fact of reducing the length of the channel network of elementary watercourses in 2023 compared to 2001 has been established. During the expedition work in 2023, the current position of the sources of elementary watercourses was established, based on comparison with the data of topographic maps of 2001, the direction of the change in the length of their channels was established and its quantitative indicators in the XXI century were calculated. In the conditions of actively plowed landscapes on the researched territory, there is a reduction in the length of the channel network of elementary watercourses.

Landscape differentiation of the territory of the Sergachsky district of the Nizhny Novgorod region (Russia)

The territory of the Sergachsky district of the Nizhny Novgorod region is located in the north of the forest-steppe zone, at the northern extremity of the Privolzhskaya Upland. Due to favorable agroclimatic conditions, the researched territory is characterized by a high degree of anthropogenic transformation of landscapes, mainly involved in agriculture. Areas of broad-leaved forests have been preserved mainly in places, that are inconvenient for plowing – on the steep slopes of river valleys and in ravines. Flat watersheds and sloping slopes have been plowing for several centuries. Thus, the landscape features of the territory traditionally determined the type of economic activity and its territorial boundaries, but often land use planning was carried out on an intuitive level, based on the experience of life in the landscape, but not on a systematic account of the specifics of its components. The long-standing and intensive economic pressure has led to a reduction in forest cover, a decrease in biodiversity, the development of erosion processes, and the degradation of soil cover. Further development of the economy in the researched area requires the adoption of well-thought-out decisions, based on the results of geosystem analysis. During solving problems of territorial planning, nature management, implementation of environmental protection measures, the most effective is the use of a landscape approach. However, until the present, the scheme of landscape differentiation of the territory of the Sergachsky district at the hierarchical level of landscapes has not been developed. The article presents the results of landscape zoning of the territory of the Sergachsky district of the Nizhny Novgorod region, performed on the basis of field research, analysis of maps, literature sources and remote sensing data processed using GIS. The presented results are the basis for making management decisions in the researched area.

Ecology and distribution of rare lichens of the Chuvash Prisurye

The paper contains data about 20 new and rare lichens of the Chuvash Prisurye. 10 lichens are new for the Chuvash Republic, 5 species are new for the Privolzhskaya Upland. The identified lichen species are indicators of old-growth, undisturbed and intact forests that have been preserved in specially protected natural areas. There are 18 species in the National Park Chuvash varmane and 8 species in the State Nature Reserve Prisursky. Geographical coordinates, distribution features in neighboring regions, ecological-substrate and phytocenotic confinement and age status are indicated for each species. The information on the ecology and distribution of rare lichen species is updated. 18 species of lichens (Bryoria nadvornikiana, Br. trichodes, Cetrelia olivetorum, Cresponea chloroconia, Evernia divaricata, Heterodermia speciosa, Leptogium cyanescens, L. saturninum, Nephroma parile, Scytinium subtile, Sc. teretiusculum, Sc. tenuissimum, Usnea dasopoga, Us. florida, Us. subfloridana, Ramalina thrausta, R. sinensis, Xanthomendoza ulophyllodes) are proposed in the new edition of the Red book of the Chuvash Republic with the Status III - rare species. 2 lichen species (Cetraria ericetorum, Lobaria pulmonaria) are classified as category II-vulnerable species, declining in number.

Geodiagnostics of lithogydrogenic systems for forecasting exoggeodynamic processes

The landscape indication, based on the automated analysis of remote sensing data, is one of the key methods of research and mapping of lithohydrogene geosystems. The article describes a set of methods for effective detection of types of lithohydrogene systems, including a set of modules for identifying dynamic and invariant descriptors of the territory; assessment of geophysical diversity of landscapes; analysis of the geophysical shell through the calculation of the descriptors of the neighborhood; ensemble-analysis of remote sensing data for monitoring the state of geosystems and forecasting of natural processes. The system of methods for detecting types of landscapes made it possible to conduct geodiagnostics of lithohydrogene systems of the Privolzhskaya Upland and the marginal part of the Oka-Don lowland reservoir within the boundaries of the Republic of Mordovia in order to predict the development of exogeodynamic processes.

Microbial communities of buried soils of the Tsaritsyn Defense Line (1718–1720)

Microbial communities of recent surface soils and the soils buried beneath the rampart of the Tsaritsyn Defense Line (1718–1720) in the Little Ice Age were studied. The contribution of the time factor to the variability in the number of microorganisms from different trophic groups was shown to be minor (0.2–0.3%), although significant. In the upper horizon of the paleosols reflecting the environmental conditions intrinsic to the period of the rampart construction, the lower (by two times) content of live microbial biomass, the lower metabolic activity of the microbial community, and the more contrasting changes in the microbiological parameters as compared to these characteristics in the recent soils were found for all the elements of the local topography. The stabilities of the microbial communities in the buried and recent soils were almost the same. The ecological–trophic structure of the microbial communities in the buried soils evidences that, the climate of the 18th century in the southern Privolzhskaya Upland was more humid than now. At the same time, temperature conditions of the Little Ice Age did not prevent the development of steppe vegetation and corresponding soil microbial communities in this area. Our data on the morphology and physicochemical properties of the soils confirm the assumption about more humid climatic conditions at the beginning of the 18th century in the studied area.

RELIEF FORMATION OF THE ROCK BENDS OF VOLGA-DON WATERSHED (WITHIN VOLGOGRADSK REGION)

The rock bends of Volga and Don (within Volgogradsk region) are considered as macro- and megabends. The data on paleogeomorphologic conditions and tectonics of the region are given. Special attention is paid to the layering of relief, the latter having much in common with the relief of the East Don ridge and the southern Privolzhskaya upland. Some hypotheses of the relief levels age and origin are discussed.

Population density and total biomass of microbial communities in chestnut soils and solonetzes of the dry steppe zone in the Lower Volga region

The population density and total biomass of microbial communities were determined in chestnut soils and solonetzes of the dry steppe zone in the Lower Volga region with the use of the methods of sequential fractionation of the soil and direct counting. The mean weighted values of the population density of the microbial communities in the soil profiles (A1 + B1 + B2 horizons) in the studied soils varied within 3.8–8.0 × 1011 cells/g of soil. The total microbial biomass in the soils of the Privolzhskaya Upland reached 0.9–2.4 mg C/g of soil; in the soils of the Ergeni Upland, it was 20 to 75% lower. The microbial cells in the soils of the Privolzhskaya Upland were larger than those in the soils of the Ergeni Upland. Sequential fractionation of the soil prior to direct counting contributed to the more complete assessment of the population density of the microbial communities.

Soil evolution and climate dynamics in dry steppes of the Privolzhskaya Upland during the last 3500 years

The investigation of paleosols of different ages buried under archaeological monuments of the Bronze (16th-15th centuries BC), Early Iron (2nd-3rd centuries AD), and Medieval (14th century AD) ages demonstrated that the evolution of chestnut soils and solonetzes in the dry steppes of the southern part of the Privolzhskaya Upland during the past 3500 years manifested itself at the level of the genus and species characteristics of the soils, such as the degree of the solonetzicity, the humus content, and the content and composition of the soluble salts. The revealed regularities of the variations of the morphological, chemical, and microbiological soil properties in time allowed reconstructing the secular dynamics of the climatic humidity in the region. It was found that the humidization of the climate with a decrease in the degree of the climatic continentality took place in the middle of the second millennium BC. The Late Sarmatian Time (2nd-3rd centuries AD) was characterized by arid climatic conditions, whereas the Golden Horde time (13th-14th centuries AD) was marked by the general humidization of the climate. A gradual aridization of the climate began in the second half of the 14th century and continued in the 15th century AD.

Phosphatase activity in the surface and buried chestnut soils of the Volga-Don interfluve

The phosphatase activity (PA) was studied in the chestnut paleosols buried in 1718–1720 under the Anna Ivanovna rampart in the southern part of the Privolzhskaya Upland and in the middle of the third millennium BC under the burial mound of the Bronze Age on the Northern Yergeni Upland; the background analogues of these soils were also examined. The PA values in the fresh soil samples varied from 2.5 to 37 mg of P2O5/10 g of soil per h with maximums in the A1 horizon of the surface soils and in the B1 horizon of the paleosols. The PA values depended on the time of storage of the samples: with time, they increased by 2.6–2.9 times in the A1 horizon of the background surface soil and decreased by 20–60% in the other soil samples. The specific distribution patterns of the PA values in the soil profiles remained the same independently of the time of storage of the samples. Relatively small amounts of the soil samples were sufficient for the reliable determination of the PA: 1–2 g for the A1 horizon and 3–5 g for the B1 and B2 horizons. The time of incubation with the substrate had to be increased up to 4 h for the long-stored samples.

Classification of woody-shrub vegetation of the forest-steppe complex of Privolzhskaya Upland

Diversity of plant communities in the nature reserve “Privolzhskaya Forest-Steppe”, Ostrovtsovsky area, is analyzed on the basis of the large-scale vegetation mapping data from 2000. The plant community classi­fication based on the Russian ecologic-phytocoenotic approach is carried out. 12 plant formations and 21 associations are distinguished according to dominant species and a combination of ecologic-phytocoenotic groups of species. A list of vegetation classification units as well as the characteristics of theshrub and woody communities are given in this paper.

Paleosol studies of burial mounds in the Ilovlya River valley (the Privolzhskaya Upland)

Paleosols buried under kurgans of the Bronze (end of the fourth and the third millennia BC), Early Iron (1st–3rd centuries AD), and Medieval (13th century AD) epochs have been studied on the Ilovlya River (a tributary of the Don River) terrace. The evolution of chestnut soils in the south of the Privolzhskaya Upland during the last 5000 years has been traced. It is shown that the mean weighted contents and distribution of soluble salts, gypsum, and carbonates in the soil profiles have been subjected to cyclic changes. The total microbial biomass and its trophic structure in the A1, B1, and B2k horizons of paleosols of different ages have been determined. A comparative analysis of the morphological, chemical, and microbiological data on the paleosols of different ages has been used to reconstruct the climatic dynamics for the last 50 centuries. The aridity of the climate in the studied region increased at the end of the third-the beginning of the second millennia BC and in the second and third centuries AD. The humidization of the climate took place in the 1st and in the 12th–13th centuries AD.