Архив метки: vegetation

HEAVY METALS IN ECOSYSTEMS OF CRYOARID LANDSCAPES OF THE WESTERN TRANSBAIKALIA

Arid Ecosystems

UDC  631.4

Chimitdorzhieva G.D., Bodeeva E.A., Chimitdorzhieva E.O. HEAVY METALS IN ECOSYSTEMS OF CRYOARID LANDSCAPES OF THE WESTERN TRANSBAIKALIA // Arid ecosystems. 2022. V.28. № 2 (91). P. 62-70. | PDF

The results of experimental work on the study of the transformation flux of heavy metals: copper, zinc, nickel and lead from parent rocks into chestnut soils, then into virgin grass stand and humic substances are presented. The soil-forming rocks are deluvial and deluvial-proluvial deposits, as well as deposits of sands and pebbles, which, as a result of their weathering, movement and redeposition, determine the unequal granulometric, mineralogical and chemical composition of rocks, affecting the composition of the soil cover. Chestnut soils are characterized by an arid climate, a long stay in a frozen state, low bioproductivity, low power, light particle size distribution, and low humus content. For the extraction of humic substances, the Grimme method was used. The determination of the content of trace elements was carried out by the atomic absorption method with direct electrothermal atomization of samples. Heavy metals were determined on an atomic absorption spectrophotometer – AAS-15 Perkin Elmer. It was revealed that, due to the depletion of rocks in copper and nickel, there are few of them in the soils, and there is more zinc and lead, which, respectively, is reflected in the vegetation and humus.

Keywords: heavy metals, humic substances, parent rocks, vegetation, chestnut soils, Western Transbaikalia.

Financing. The work was carried out on the topic of state task No. 121030100228-4 «Evolutionary-genetic, biogeochemical and productive functions of soils of the Baikal region as a component of the biosphere, assessment of their resource potential and development of technologies for rational use and protection» 2021-2022.

DOI: 10.24412/1993-3916-2022-2-62-70

TRENDS IN HYDROTHERMAL INDICATORS OF THE STEPPES OF SOUTH-EASTERN TRANSBAIKALIA IN THE CONTEXT OF CLIMATE WARMING

Arid Ecosystems

Davydova N.D. TRENDS IN HYDROTHERMAL INDICATORS OF THE STEPPES OF SOUTH-EASTERN TRANSBAIKALIA IN THE CONTEXT OF CLIMATE WARMING // Arid ecosystems. 2022. V.28. № 1 (90). P. 3-10 . | PDF

One of the problems of the development of society on Earth was climate change due to the increase in the temperature of the surface layer of air, which for different regions was and remains not equal. The analysis of long-term data on air temperature, atmospheric precipitation and humidity of deep-frozen powdery-carbonate chernozems of the Onon-Argun steppe of South-Eastern Transbaikalia is carried out. It is shown that the next dry period of 1999-2020 differs from the previous one by a significant increase in temperature and an ambiguous annual amount of precipitation. According to these indicators, it is divided into two parts: very dry warm and wet very warm. In the driest period (2001-2011), the moisture reserves in the soils were mostly at the level of withering humidity and below. In nature, there were such catastrophic phenomena as the widespread drying of stands of trees, the disappearance of lakes, including a large one-Barun-Torey. Since 2012, the amount of precipitation has increased, but has had little effect on the soil moisture reserves and the replenishment of the water volume in the lakes. As a result, by 2018, the water area of another large lake of the Torey depression – Zun-Torey-disappeared. The bottoms of the dried-up lakes turned into soda-sulfate sodium and soda- chloride-sulfate sodium salt marshes. In the terrestrial grassland of the steppes, the introduction of xerophilic species into the communities was observed, as well as a decrease in its height and density. The amount of aboveground plant mass decreased by 1.5-2.0 times.

Keywords: global warming, Onon-Argun steppe, atmospheric precipitation, air temperature, humidity, soil, lake drying, vegetation, xerophilic species, stand of trees.

Acknowledgement. The author is grateful to the head of the Borzya meteorological station, L.I. Karpikova, hydrologist O.V. Perminova and all the employees who worked in different years for their long-term assistance in the selection of materials, consultations, understanding and warm friendly attitude, as well as Ph.D. L.V. Dudareva, who took a direct part in the formation of the Chemical Analytical Center of the Institute of Geography of the SB RAS and its accreditation, the development of the instrument base and the receipt of KHA data.

Financing. The work was carried out at the expense of the state assignment of the IG SB RAS, state registration No. AAAA17-117041910171-7, “Spatial and temporal patterns of the material state of the landscapes of Siberia in changing environmental conditions”.

DOI: 10.24412/1993-3916-2022-1-3-10

IMPACT OF ENVIRONMENTAL CONDITIONS ON THE SOIL PROCESSES OF THE HIGHLANDS OF DAGESTAN

Arid Ecosystems

Alichaev M.M., Sultanova M.G. IMPACT OF ENVIRONMENTAL CONDITIONS ON THE SOIL PROCESSES OF THE HIGHLANDS OF DAGESTAN // Arid ecosystems. 2021. V.27. № 3 (88). P. 61-65.

The article presents the materials of route, stationary soil, soil-ecological studies conducted in the high-mountain zone of Dagestan with the characteristic: a) the current features of the development of the soil cover; b) the ecological parameters of the soil cover and their changes under the influence of climate warming.

The variety of natural and economic conditions of the object of study caused a significant diversity of the soil cover. The distribution of the soil was greatly influenced by the height of the terrain, the exposure and the steepness of the slopes. Based on the soil erosion studies conducted in previous periods, it can be noted that improper land use and climate warming have led to radical changes in the composition of the soil cover in terms of determining indicators – soil erosion.

In recent years, the area of eroded land has doubled, the area with heavily eroded soils-by 1/3. This led to a decrease in the thickness of humus horizons in almost all soils to an average of 20 cm, and the loss of humus reserves in the soils amounted to 60% of the initial content. The presented analysis of the degradation of the soil cover and the established patterns of soil evolution on the slope lands of the highlands serve as a theoretical basis for the reproduction of soil fertility, the preservation of the ecological role of soil protection from erosion and other degradation processes.

Keywords: soil, fertility, erosion, exposure, highlands, vegetation, ecology, pastures, elevation.

Funding. This work was carried out within the state assignment No. 0733-2019-0005 “To Develop an Assessment System for Modern Trends of Soil Processes Development in Natural Landscapes of the Mountainous Province of the Republic of Dagestan”.

DOI: 10.24411/1993-3916-2021-10164

SEASONAL DYNAMICS OF THE STRUCTURE OF THE COMMUNITIES OF SOIL NEMATODES IN CHESTNUT SOILS OF THE MANYCH VALLEY UNDER PASTURE LOAD

Arid Ecosystems

Shmatko V.Yu.,  Sushko K.S.,  Sokolova T.A., Ilyina L.P. SEASONAL DYNAMICS OF THE STRUCTURE OF THE COMMUNITIES OF SOIL NEMATODES IN CHESTNUT SOILS OF THE MANYCH VALLEY UNDER PASTURE LOAD // Arid ecosystems. 2021. V. 27. № 1 (86). P. 106-118. | PDF

In this article, two key areas with virgin and pasture biotopes were studied, for which soil parameters were determined, a brief description of the vegetation was given, and the spectral reflectance properties of the vegetation cover (NDVI) were calculated using Landsat 8 OLI images.

The seasonal dynamics of the structure of soil nematode communities in chestnut solonetzic soils under pasture load has been studied. A number of features have been identified that are manifested in the species diversity of the fauna, changes in the total number, domination of certain trophic groups and genera.

For the studied areas, 133 taxa were identified, exact species identification is given for 58 species. It has been established that the features of soil nematode communities in different seasons of the year are manifested in the dominance of certain trophic groups and genera, as well as their total number at key sites.

In general, the fauna of nematodes can be assessed as quite diverse – Shannon’s index (Hˊ) throughout the year at all sites varied within the same values. The nematode community maturity index by Bongers (MI) indicates the stability of their habitat conditions.

Keywords: soil nematodes, chestnut solonetzic soils, pasture load, vegetation, ecological and trophic composition, diversity index, community maturity index.

DOI: 10.24411/1993-3916-2021-10142

ASSESSMENT OF SPATIAL – TEMPORAL VARIABILITY OF ARID ECOSYSTEMS IN THE REPUBLIC OF BURYATIA

Arid Ecosystems

Garmaev E.Zh.,  Ayurzhanaev A.A.,  Tsydypov B.Z.,  Alymbaeva Zh.B.,  Sodnomov B.V., Andreev S.G.,  Zharnikova M.A.,  Batomunkuev V.S.,  Mandakh N., Salikhov T.K.,  Tulohonov А.К.  ASSESSMENT  OF  SPATIAL – TEMPORAL VARIABILITY OF ARID ECOSYSTEMS IN THE REPUBLIC OF BURYATIA // Arid ecosystems. 2020. V. 26. № 2 (83). P. 34-42. | PDF

Climate change and human activity on the territory of the Republic of Buryatia intensify the processes of desertification and land degradation. Zoning of the territory of Buryatia was carried out according to the aridity index using ENVIREM high spatial resolution climatic data. Based on the correlation analysis of the time series of the NDVI AVHRR vegetation index, meteorological series of the NCEP / NCAR reanalysis and field studies, a quantitative assessment of the long-term changes in vegetation cover in arid and humid zones was carried out. Maps of the spatial distribution of linear trends of NDVI and precipitation for 1982-2015 with the separation of wet (1982-1999) and dry periods (2000-2015) were obtained. During the wet period, positive NDVI trends are observed for almost the entire territory of the Republic, while the dry period is characterized by a significant increase in the negative trends of the vegetation index. The positive correlation between the Selyaninov hydrothermal coefficient and NDVI is observed for intermountain steppificated hollows, negative for forest landscapes. The dynamics of NDVI of steppe vegetation largely depends on precipitation, the dynamics of NDVI of forests — on temperature. Reforestation, post-pyrogenic succession, shrubbing of abandoned fields, etc., cause the increase of NDVI. Negative NDVI trends are typical for steppe ecosystems under conditions of decreasing precipitation, and for forest vegetation prone to cuttings and fires.

Keywords: Buryatia, arid zones, vegetation, NDVI, Selyaninov hydrothermal coefficient, precipitation, trend, reanalysis, dendrochronology.

DOI: 10.24411/1993-3916-2020-10093