Архив метки: climate change

BIODIVERSITY OF MALACOFAUNA IN THE CASPIAN-MANYCH-PONT SYSTEM DURING THE LAST INTERGLACIAL EPOCH

Arid Ecosystems

UDC 551.41

Yanina T.A.,  Semikolennykh D.V.,  Sorokin V.M. BIODIVERSITY OF MALACOFAUNA IN THE CASPIAN-MANYCH-PONT SYSTEM DURING THE LAST INTERGLACIAL EPOCH // Arid Ecosystems. 2024. Vol. 30. № 2 (99). P. 119-135. | PDF

The conditions of the biodiversity formation and their comparative analysis at individual stages of development of the Ponto-Caspian basins in the MIS 5 epoch have been identified. The work was carried out based on the results of studying materials from many years of field research in the Caspian, AzovBlack Sea regions and the Manych Depression. The biodiversity of malacofauna in the Caspian-ManychPont system under the climatic conditions of the MIS 5 epoch was closely linked with the basin’s history. Two transgressive basins, Late Khazarian and Hyrcanian, have been reconstructed in the Caspian Sea. The Late Khazarian malacofauna of the northern part of the paleo-Caspian Sea is represented by 26 species. The majority of the Late Khazarian species belongs to the Cardiidae family and are Caspian endemics. The main species is Didacna surachanica Andrusov, 1910. The Hyrcanian malacofauna includes 22 species, the majority of which are also Caspian endemics. The main species are Didacna subcatillus Andrusov, 1910 and Didacna cristata Bogachev, 1932. The malacofauna composition is influenced by factors such as inheritance from the previous basin, aquatic environment’s salinity and temperature, and the introduction of freshwater fauna with river runoff. The significant impact of unexpected catastrophic events, such as the sudden break of a periglacial lake and the subsequent flow of its waters into the Caspian Sea, has led to a sharp change in the biodiversity of the Hyrcanian basin in comparison to the Late Khazarian basin. The Pont’s Karangatian transgression occurred in three stages. In the northeastern part of the Pont, the malacofaunal composition consists of 37 species, mostly Mediterranean species, both
euryhaline and stenohaline. Each stage is characterized by its malacofaunal complex, which includes varying degrees of euryhaline or stenohaline elements. The second complex, corresponding to the maximum stage of transgression, was characterized by the greatest diversity and the presence of the most halophilic elements. An important feature of the third complex is the presence of Caspian species characteristic of the Hyrcanian transgression of the Caspian Sea. The events that occurred in the Manych Depression, which are closely associated with the evolution of the Caspian and the Pont, have been reconstructed: the ingression gulf of the Karangatian transgression of the Pont in the second stage of its development; reduction in the length of the bay, with the simultaneous advance of waters of the Hyrcanian transgression and their discharge into the bay; complete release of the Manych Depression from the Karangatian waters and the discharge of the waters of the Hyrcanian transgression into the Karangatian basin in the third stage of its development. The Pont’s species diversity was determined by the malacofauna composition that migrated from the Mediterranean Sea. At the final stages of the development of the Karangatian transgression its faunal composition was influenced by Caspian invasive species that penetrated the Pont with the waters of the Hyrcanian transgression through the Manych Strait. The composition of malacofauna in the Caspian Sea was primarily the result of evolutionary processes. Migration was the main factor in the formation of the Black Sea malacofauna, without any evolutionary influence.

Keywords: Late Pleistocene, climate change, Late Khazarian transgression, Hyrcanian transgression, Karangatian transgression, species evolution, malacofauna migration.

Acknowledgments. This study was financially supported by the Russian Science Foundation, project No. 22-27-00164 (2022-2023) “Environmental evolution of the Ponto-Caspia region during the last interglacial epoch”.

Funding. The study was carried out with support of the Russian Science Foundation project No. 22-27-00164 (2022-2023) «Evolution of the natural environment of the Ponto-Caspian Sea in conditions of the last interglacial epoch».

DOI: 10.24412/1993-3916-2024-2-119-135
EDN: NVDSVE

SPATIAL-TEMPORAL VARIABILITY OF THE DISTRIBUTION OF CLIMATE INDICATORS OF THERMAL AGROCLIMATE RESOURCES (ARARAT VALLEY AND FOOTHILL ZONE, ARMENIA)

Arid Ecosystems

UDC 551.582;551.583.1(470.31)

Margaryan V.G., Gaidukova E.V., Sedrakyan A.M. SPATIAL-TEMPORAL VARIABILITY OF THE DISTRIBUTION OF CLIMATE INDICATORS OF THERMAL AGROCLIMATE RESOURCES (ARARAT VALLEY AND FOOTHILL ZONE, ARMENIA) // Arid Ecosystems. 2023. Vol. 29. № 4 (97). P. 135-147. | PDF

 In this work, the characteristics of thermal agro-climatic resources of the Ararat valley and the foothill zone are studied and calculated, the patterns of their spatial and temporal distribution, as well as interannual variability, are analyzed and evaluated. Previously published works and relevant studies served as theoretical and informational foundations for this work. Daily data of actual observations of meteorological stations of the «Hydrometeorology and Monitoring Center» SNCO of the Ministry of Environment of the Republic of Armenia in the study area, as well as agro-climatic reference books and yearbooks were used as the source material. The following methods were applied in the work: mathematical-statistical, extrapolation, interpolation, analytical, correlation, as well as methods of analysis and analogue.

It turned out that the territory of the Ararat valley and the foothill zone, which has a relatively arid climate, is the most favorable agricultural region of the republic in terms of climatic indicators of thermal agro-climatic resources. The thermal conditions of the region are favorable for the growth and development of various crops; however, the danger of late spring and early autumn frosts must be considered. Measures for adapting agricultural production to climate change are proposed. The results obtained can be used in planning the development of agricultural production on the territory of the Ararat valley and the foothill zone, in the development of agro-climatic cadastres of territories and climatic services for sectors of the national economy.

Keywords: dates of stable transition of the average daily air temperature through 0, 5 and 10°C in spring and autumn, climatic spring, climatic autumn, growing season, climate change, Ararat valley and foothill zone, Armenia.

Funding. The work was supported by the Science Committee of RA, in the frames of the research project 21T-1E215 «Hydro-ecological assessment of winter low water period discharge characteristics of lake Sevan basin rivers»

DOI: 10.24412/1993-3916-2023-4-135-147

EDN: TDVLJJ

INFLUENCE OF SOIL-CLIMATE FACTORS ON GROUNDWATER PARAMETERS OF SLOPE AGRICULTURAL LANDSCAPE

Arid Ecosystems

UDC 556.31; 631.432.1

Buzueva A.S., Gubarev D.I., Nesvetaev M.Yu., Kulikova V.A. INFLUENCE OF SOIL-CLIMATE FACTORS ON GROUNDWATER PARAMETERS OF SLOPE AGRICULTURAL LANDSCAPE // Arid Ecosystems. 2023. Vol. 29. № 2 (95). P. 20-28. | PDF

The purpose of our research was to establish the influence of soil and climatic factors on the depth of occurrence and the degree of salinization of groundwater in the slope-hollow landscape. The hydrogeological data served as the basis for our research, obtained in 1990-2021 for 6 wells at the research stations of the Federal Center of Agriculture Research of the South-East Region. The dynamic changes in the groundwater level were analyzed in various relief elements in the wells located on the Elshan-Guselka Plain of Saratov, in the Volga Upland. The analysis specified that there was a general trend towards an increase in the groundwater level, both in the watershed and the slope-hollow relief. The chemical composition of atmospheric precipitation turned out to be the main source of groundwater nutrition. Sulfates (35%) had the largest percentage of the total chemical composition of sediments, while hydrocarbonates had 22%. The main ions that determined the chemical type and degree of mineralization of the studied waters were identified as well. The exceeding average values of the maximum concentration limit was established for sulfates, calcium, magnesium and sodium. The level of water salinity in the watersheds was 27% higher than in the lower part of the slope. According to long-term average data, groundwater, sampled according to relief elements, was saline.

Keywords: climate change, groundwater, chemical composition of groundwater.

Funding. The research was carried out for the state task No. FNWF-2022-0007 “Formation of Principles of Ecosystem Management and Agricultural Production Based on Digitalization and Forecasting of Soil and Climatic Changes”.

DOI: 10.24412/1993-3916-2023-2-20-28

EDN: GBXGNB

REGIONAL CLIMATE CHANGES IN DRY STEPPES AND THEIR CONNECTION TO DROUGHTS

Arid Ecosystems

UDC 551.583:632.125

Pugacheva A.M., Belyaev A.I., Trubakova K.Yu., Romadina O.D. Regional Climate Changes in Dry Steppes and their Connection to Droughts // Arid Ecosystems. 2022. Vol. 28. № 4 (93). P. 13-21. | PDF

The authors carried out an analysis of the regional climate for separate administrative districts of the Volgograd region for the first time. Differences were revealed based on temperature data and incoming precipitation. The study of the Volgograd region in the context of natural and climatic zones and subzones is of particular interest. This makes it possible to analyze multidirectional trends of climate change in a limited area. The open data of the climatic archive (VNIIGMI-MCD) on 5 reference weather stations of the region located in the dry steppes of chestnut soils were used in the work. The droughts were calculated on the basis of temperature and precipitation anomalies using Pedj Drought Index. Regional changes in the climate were identified in terms of the flow of precipitation during the seasons of active vegetation (spring, summer) according to long-term time series of data from registered meteorological stations. Regression analysis showed an increase in their reception in the spring and a decrease in the summer. Also, an increase in the number of droughts in the summer period was revealed with a decrease in aridity. This effect increases the intensity using Pedj Drought Index, the value of which reaches 3 units. A slight inverse correlation was found between the amount of incoming precipitation and the number of droughts in the summer in Volgograd, Surovikinsky, Ilovlinsky and Kamyshinsky districts and dry phenomena in the Surovikinsky district, as well as a direct moderate dependence on droughts in the Kamyshinsky district in summer. Areas with the maximum number of drought events have been identified, therefore, having the maximum risks of agricultural production. In Kamyshinsky district there were 21 drought events in spring, 115 in summer and in Surovikinsky district there were 4 drought events in spring, 70 in summer. In accordance with the results obtained, especially in the regions most susceptible to the influence of droughts, it is necessary to adjust the existing crop rotation schemes, the range of cultivated crops and a shift in emphasis towards conducting reclamation agriculture in these territories in order to eliminate the risks of agricultural production with the effective use of land resources. Regional climate studies are necessary for conducting effective agricultural activities. This makes it possible to objectively assess the situation with climate change at the level of administrative districts. The information obtained is necessary for the purpose of making managerial, risk-free decisions for agricultural production for agricultural regions.

Keywords: climate change, seasons of active vegetation, moisture availability during the seasons of active vegetation, droughts, aridity, dry steppe, chestnut soils.

Acknowledgements. The authors are grateful to the research engineer of the Laboratory of Geoinformation Modeling and Mapping of Agroforestry Landscapes of the Federal Research Center of Agroecology of the Russian Academy of Sciences A.A. Vasilchenko for the cartographic material prepared for the article.

Funding.The work was carried out within the framework of the State Task of the Federal Research Center of Agroecology of the Russian Academy of Sciences «Theoretical foundations of the functioning and natural-anthropogenic transformation of agroforestry complexes in transitional natural-geographical zones, patterns and forecast of their degradation and desertification based on geoinformation technologies, aerospace methods and mathematical cartographic modeling in modern conditions».:

DOI: 10.24412/1993-3916-2022-4-13-21

EDN: ZNQHLZ

INFLUENCE OF CLIMATE CHANGE ON SOIL DEGRADATION IN ARID ZONES OF THE VOLGA REGION

Arid Ecosystems

UDC 631.434.52:504.123(470.4)

Gubarev D.I., Levitskaya N.G., Derevyagin S.S. INFLUENCE OF CLIMATE CHANGE ON SOIL DEGRADATION IN ARID ZONES OF THE VOLGA REGION // Arid ecosystems. 2022. V.28. № 1 (90). P. 20-27. | PDF

The aim of the research was to establish the impact of climate change on the processes of soil degradation and desertification in the arid zones of the Volga region. The material for the research was the observational data for 1971-2020 on 20 meteorological stations, as well as the results of soil-ecological and hydrogeological monitoring at research stations of the Federal State Budgetary Scientific Organization «Federal Center of Agriculture Research of the South- East Region» in the prevailing soil and climatic zones on the territory of the Saratov region (forest-steppe, steppe, dry steppe and semi-desert). Identified signs accompanying aridization, desertification and land degradation differentiated by natural zones. In particular, the average annual air temperature increased, compared with the climatic norm, by 1.0-1.2°С, the greatest increase was observed in August (by 2.0-2.2°С). The average temperature of the soil surface during the warm period increased by 1.1-1.5°C. The risks of severe atmospheric droughts during the entire growing season increased throughout the entire territory, most noticeably in the semi-desert zone (from 55 to 82%). The amount of precipitation in the spring increased by 10-25%, and in the summer – decreased by 23-30%. The boundaries of the semi-desert zone have shifted to the north and northwest. The tendency of changes in the hydrological regime of zonal soils from non-leaching to periodically leaching in 20-40% of years is outlined. The values of the aridity indices of the territory, calculated for the period from 2001 to 2020, increased in comparison with the climatic norm for 1971-2000 by 3-6%. This is an indicator of an increase in climate aridity during its current warming. As a result, high rates of dehumification (decrease in the relative humus content by 21-35%) and changes in the structural state of the arable layer and grain size distribution (decrease in water-resistant aggregates >0.25 mm from 39 to 31.8% and the absolute content of physical clay by 7.5%). At the same time, there is an increase in the mineralization of groundwater from 2500 to 7000 mg/l, as well as an increase in the content of toxic salts in the soil solution. Thus, the content of Cl—, SO42— ions in the places of replenishment with groundwater increased from 0.27 to 0.56 mg/eq. and from 0.27 to 13.27 mg/eq. respectively. The cation values also increased: Ca2+ – from 0.30 to 4.41 mg/eq., Mg2+ – from 0.12 to 5.59 mg/eq., The sum of K+ and Na+ – from 0.09 to 0.28 mg/eq. In the lowered elements of the relief, the development of processes of local salinization and waterlogging is noted.

Keywords.Climate change, aridization, drought, degradation, salinization.

Financing. The article was made within the state assignment No. 0751-2019-0008 “To develop theoretical foundations for structuring agricultural landscapes, adapting them to climatic and geomorphometric features of the territory in order to preserve and optimize the use of land resources to obtain an economically reasonable level of quality agricultural products”.

DOI: 10.24412/1993-3916-2022-1-20-27

SPATIAL DIFFERENTIATION OF CLIMATE CHANGE IMPACT ON AGRICULTURE IN AKMOLA REGION

Arid Ecosystems

Smagulov Ye.N. SPATIAL DIFFERENTIATION OF CLIMATE CHANGE IMPACT ON AGRICULTURE IN AKMOLA REGION // Arid ecosystems. 2021. V.27. № 3 (88). P. 72-80.

Long-term dynamics of average air temperatures and annual precipitation amounts confirms the reality of climatic changes that began in the 70th of the last century in the Akmola region that is one of the leading agricultural regions of Kazakhstan. Cultivation of cereals, in particular, spring wheat, which is known to be extremely sensitive to climatic and weather conditions, prevails in the structure of agricultural production of the region. Based on the analysis of climatic indicators for 1931-2019, according to the available data of meteorological stations, the intraregional features of climate change, which led to an increase in the yield of grain crops, were identified. Correlation analysis established a high dependence of yield on the climatic conditions of the warm period. With the preservation of the current level of farming culture and the continued growth of average temperatures, a decrease in yield is expected in dry-steppe and southern steppe regions of the region. In the northern steppe regions, more intense trends in climatic indicators of the cold months favor an increase in yields and an expansion of agricultural production. Further development of agriculture in Akmola region requires taking into account intraregional differences in the intensity of climatic trends. In order to avoid the negative consequences of climate change, it is proposed to introduce adaptation technologies, to diversify agricultural production, to develop organic agriculture and actively to support agricultural producers.

Keywords: adaptation, agriculture, agroclimatic resources, cereals, climate change, dry steppe zone, long-term dynamics, Northern Kazakhstan, steppe zone, yield.

Funding. This work was carried out as part of the Research Project of the Geographical Faculty of Moscow State University.

DOI: 10.24411/1993-3916-2021-10166

SEASONAL DYNAMICS OF THE UNDERGROUND PART OF THE EPHEMERAL-WORMWOOD SEMI-DESERT OF THE KURA-ARAZ LOWLAND IN MODERN CLIMATIC CONDITIONS

Arid Ecosystems

Ganiyeva S.A., Gurbanov E.A. SEASONAL DYNAMICS OF THE UNDERGROUND PART OF THE EPHEMERAL-WORMWOOD SEMI-DESERT OF THE KURA-ARAZ LOWLAND IN MODERN CLIMATIC CONDITIONS // Arid ecosystems. 2021. V. 27. № 1 (86). P. 54-61. | PDF

This article discusses the patterns of the dynamics of the underground part of the ephemeral-wormwood semi-desert of the Kura-Araz lowland in conditions of climate change. It was found that regardless of the plant development phase, season of the year and climate change conditions in different years, the ratio of productive and unproductive roots of plants remains at a certain level. The authors of the article determine the objects and methods of research that were conducted by them in different time periods in different climatic conditions. The authors provide figures and data (in tables) illustrating repeated experiments and observations. On the basis of scientifically grounded descriptions, the authors come to the conclusion that with the deepening into the soil, a decrease in the root mass in plant communities occurs with a pronounced regularity.

Keywords: climate change, ephemera, wormwood, root system, underground phytomass, soil.

DOI: 10.24411/1993-3916-2021-10137