The South Aral Seabed is an extreme dryland ecosystem undergoing rapid transformation yet remains misrepresented or absent in global land cover datasets.Conventional vegetation indices,specifically the Normalized Diff...The South Aral Seabed is an extreme dryland ecosystem undergoing rapid transformation yet remains misrepresented or absent in global land cover datasets.Conventional vegetation indices,specifically the Normalized Difference Vegetation Index(NDVI),perform poorly in such environments due to their limited ability to distinguish sparse vegetation from highly reflective saline and sandy soils.This study evaluated the effectiveness of the Modified Soil Adjusted Vegetation Index(MSAVI)for improving land cover classification in the South Aral Seabed and conducted a decadal analysis of land cover change between 2013 and 2023 using Landsat 8 imagery(30 m resolution).A spectral index-based classification framework was developed,combining MSAVI with the Normalized Difference Water Index(NDWI)and Salinity Index 1(SI1)to reduce spectral confusion between vegetation,saline soils,and surface water.The MSAVI-based classification achieved an overall accuracy of 77.96%(Kappa coefficient=0.71),supported by 313 field-collected validation points from 2023.While the multi-index approach enabled finer discrimination of ecologically important classes,particularly separating salt pans from solonchak soils,it resulted in a lower overall accuracy(73.80%),highlighting a trade-off between class separability and classification performance.Land cover change analysis revealed a highly dynamic landscape,with 52.96%of the study area transitioning between classes over the decade.Transformed areas(16,893 km2)exceeded stable zones(15,004 km2),driven primarily by rapid desiccation and salinization.Solonchak soils increased at an annual rate of 5.58%,while surface water bodies declined by 4.83%per year.Concurrently,sparse or distressed vegetation increased by 1.43%annually,reflecting ongoing afforestation efforts.This study provides the first MSAVI-based and medium-resolution land cover baseline for the South Aral Seabed and demonstrates that soil-adjusted vegetation indices are essential for reliable dryland classification where conventional indices fail.The proposed spectral index framework offers a replicable methodology applicable to other global drylands facing similar land degradation and restoration challenges.展开更多
The Aral Sea was one of the largest lakes in the world before it started to shrink in the 1960s due to water withdrawal for agricultural irrigation. Precipitation decreased from 9.4 kmin 1960 to 3.2 km3 in 2009, and a...The Aral Sea was one of the largest lakes in the world before it started to shrink in the 1960s due to water withdrawal for agricultural irrigation. Precipitation decreased from 9.4 kmin 1960 to 3.2 km3 in 2009, and annual river inflow into the Aral Sea decreased from 31.5 km3 in 1998 to 5.2 km3 in 2009. Comparison on the hydrological data of the Aral Sea between 1960 and 2009 showed the evaporation, water surface area, and water volume decreased by 90%, 80%, and 88%, respectively. This study employs the observed values of water volume, precipitation, runoff, evaporation, and salinity to estimate water volume and salinity from 1960 to 2009, and the efficiency coefficients for predicted water volume and salinity are o.975 and 0.974, respectively. Regression equations calculated from the observed data are used to predict precipitation, runoff, evaporation, and salinity from 20lO to 2021, and the results are then applied in the estimation of water volume and salinity Our estimates suggest that salinity will increase to around 200 g/L and water volume will decrease to around 83 km3 in 2021.展开更多
The Aral Sea was the fourth largest lake in the world but it has shrunk dramatically as a result of irrational human activities, triggering the "Aral Sea ecological crisis". The ecological problems of the Ar...The Aral Sea was the fourth largest lake in the world but it has shrunk dramatically as a result of irrational human activities, triggering the "Aral Sea ecological crisis". The ecological problems of the Aral Sea have attracted widespread attention, and the alleviation of the Aral Sea ecological crisis has reached a consensus among the five Central Asian countries(Kazakhstan, Uzbekistan, Tajikistan, Kyrgyzstan, and Turkmenistan). In the past decades, many ecological management measures have been implemented for the ecological restoration of the Aral Sea. However, due to the lack of regional planning and zoning, the results are not ideal. In this study, we mapped the ecological zoning of the Aral Sea from the perspective of ecological restoration based on soil type, soil salinity, surface water, groundwater table, Normalized Difference Vegetation Index(NDVI), land cover, and aerosol optical depth(AOD) data. Soil salinization and salt dust are the most prominent ecological problems in the Aral Sea. We divided the Aral Sea into 7 first-level ecological restoration subregions(North Aral Sea catchment area in the downstream of the Syr Darya River(Subregion Ⅰ);artificial flood overflow area in the downstream of the Aral Sea(Subregion Ⅱ);physical/chemical remediation area of the salt dust source area in the eastern part of the South Aral Sea(Subregion Ⅲ);physical/chemical remediation area of severe salinization in the central part of the South Aral Sea(Subregion Ⅳ);existing water surface and potential restoration area of the South Aral Sea(Subregion Ⅴ);Aral Sea vegetation natural recovery area(Subregion Ⅵ);and vegetation planting area with slight salinization in the South Aral Sea(Subregion Ⅶ)) and 14 second-level ecological restoration subregions according to the ecological zoning principles. Implementable measures are proposed for each ecological restoration subregion. For Subregion Ⅰ and Subregion Ⅱ with lower elevations, artificial flooding should be carried out to restore the surface of the Aral Sea. Subregion Ⅲ and Subregion Ⅳ have severe salinization, making it difficult for vegetation to grow. In these subregions, it is recommended to cover and pave the areas with green biomatrix coverings and environmentally sustainable bonding materials. In Subregion Ⅴ located in the central and western parts of the South Aral Sea, surface water recharge should be increased to ensure that this subregion can maintain normal water levels. In Subregion Ⅵ and Subregion Ⅶ where natural conditions are suitable for vegetation growth, measures such as afforestation and buffer zones should be implemented to protect vegetation. This study could provide a reference basis for future comprehensive ecological management and restoration of the Aral Sea.展开更多
The gradual shrinkage of the Aral Sea has led to not only the degradation of the unique environments of the Aral Sea,but also numerous and fast developing succession processes in the neighborhood habitats surrounding ...The gradual shrinkage of the Aral Sea has led to not only the degradation of the unique environments of the Aral Sea,but also numerous and fast developing succession processes in the neighborhood habitats surrounding the sea.In this study,we investigated the vegetative succession processes related to the Aral Sea shrinkage in the Eastern Cliff of the Ustyurt Plateau in Republic of Uzbekistan,Central Asia.We compared the results of our current investigation(2010–2017)on vegetative communities with the geobotany data collected during the 1970s(1970–1980).The results showed great changes in the mesophytic plant communities and habitat aridization as a result of the drop in the underground water level,which decreased atmospheric humidity and increased the salt content of the soil caused by the shrinkage of the Aral Sea.In the vegetative communities,we observed a decrease in the Margalef index(DMg),which had a positive correlation with the poly-dominance index(I-D).The main indications of the plant communities'transformation were the loss of the weak species,the appearance of new communities with low species diversity,the stabilization of the projective cover of former resistant communities,as well as the appearance of a new competitive species,which occupy new habitats.展开更多
The increase of irretrievable river water withdrawals and regulation of river flow has a negative effect on the natural regime of the Aral Sea. The Ainu Darya River and the Syr Darya River Basins are the largest irrig...The increase of irretrievable river water withdrawals and regulation of river flow has a negative effect on the natural regime of the Aral Sea. The Ainu Darya River and the Syr Darya River Basins are the largest irrigated farming areas. Their favorable soil and climatic conditions ensure guaranteed yields of various crops on irrigated lands. Since 1961, for the drastic increase of irretrievable river water withdrawal, mainly for irrigation, the inflow of fiver water into the Aral Sea has started to decrease significantly, accordingly the sea＇s hydrological and hydrochemical regimes disrupted dramatically. The sea level has continued to drop as evaporation exceeds inflow. This negatively transforms the natural environment and worsens socio-economic conditions in Priaralie as a whole, especially in the lower reaches of Amu Darya and Syr Darya, where natural conditions are largely determined by the sea＇s impact. At present, this causes desertification of the nonirrigated zone in the deltas, spreading to new areas as the Aral Sea dries out.展开更多
The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the B...The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the Bayesian Estimator of Abrupt change,Seasonal change,and Trend(BEAST)model to detect the historical change points in the variation of the Aral Sea and the Amu Darya River and analyse the causes of the Aral Sea shrinkage during the 1950–2016 period.Further,we applied multifractal detrend cross-correlation analysis(MF-DCCA)and quantitative analysis to investigate the responses of the Aral Sea to the runoff in the Amu Darya River,which is the main source of recharge to the Aral Sea.Our results showed that two significant trend change points in the water volume change of the Aral Sea occurred,in 1961 and 1974.Before 1961,the water volume in the Aral Sea was stable,after which it began to shrink,with a shrinkage rate fluctuating around 15.21 km3/a.After 1974,the water volume of the Aral Sea decreased substantially at a rate of up to 48.97 km3/a,which was the highest value recorded in this study.In addition,although the response of the Aral Sea's water volume to its recharge runoff demonstrated a complex non-linear relationship,the replenishment of the Aral Sea by the runoff in the lower reaches of the Amu Darya River was identified as the dominant factor affecting the Aral Sea shrinkage.Based on the scenario analyses,we concluded that it is possible to slow down the retreat of the Aral Sea and restore its ecosystem by increasing the efficiency of agricultural water use,decreasing agricultural water use in the middle and lower reaches,reducing ineffective evaporation from reservoirs and wetlands,and increasing the water coming from the lower reaches of the Amu Darya River to the 1961–1973 level.These measures would maintain and stabilise the water area and water volume of the Aral Sea in a state of ecological restoration.Therefore,this study focuses on how human consumption of recharge runoff affects the Aral Sea and provides scientific perspective on its ecological conservation and sustainable development.展开更多
The greatest environmental disaster in Central Asiathe drying up of the Aral Seahas led to the formation of a new terrain, extending over 2.7 million hectares in Uzbekistan. This newly formed terrain is dynamically de...The greatest environmental disaster in Central Asiathe drying up of the Aral Seahas led to the formation of a new terrain, extending over 2.7 million hectares in Uzbekistan. This newly formed terrain is dynamically developing, with emerging soil formations replacing bottom sediments. This paper analyzes the results of a study on soil formation in the eastern part of the dried-up seabed, focusing on the influence of natural processes occurring there.展开更多
The effects of human activities on the soil cover transformation in the eastern part of Kazakhstan were investigated during the period of 1956-2008.The results of the research for different soil types in Priaralye ind...The effects of human activities on the soil cover transformation in the eastern part of Kazakhstan were investigated during the period of 1956-2008.The results of the research for different soil types in Priaralye indicated that there was 643.3×103 hm2 solonchaks,accounting for 38.5 % of the total area（1670.5×10^3 hm^2） in 2008.Vast areas are occupied with dried lakeshore soil（311.1× 10^3 hm^2）,sandy soils（147.6×10^3 hm^2） and grey-brown desert soils and solonetzes（146.7×10^3 hm^2）.In 2001 the area of solonchak was 755×103 hm2 and decreased to 643.3×10^3 hm^2 in 2008,which due to the shrinkage of the Aral Sea,the areas of marsh and lakeshore solonchaks decreased with the increase of dried bottom of the Aral Sea.The level of soil cover transformation in the modern delta of the Syr-Darya River can be seen from the comparison of the results obtained from the different years in the study area.The area of solonchaks increased by 10×10^3 hm^2 and the area of alluvial-meadow salinizied soils increased by 17.9×10^3 hm^2 during the period of 1956-1969.It means that many non-salinizied soils were transformed into salinizied ones.Striking changes occurred in the structure of soil cover as a result of aridization.So,the researches in1969 significantly determined the areas of hydromorphic soils subjected to desertification（it was not fixed on the map before 1956）.Later,these soils were transformed into takyr-like soils.The area of takyr-like soils increased almost by 3 times for 34 years（from 1956 to 1990）.The long-term soil researches on soil cover transformation in Priaralye have shown that the tendencies of negative processes（salinization and deflation） are being kept and lead to further soil and eco-environment degradation in the region.展开更多
A new salty and sandy desert of ca 5 million ha has emerged on the exposed Aral Sea bed. Every year, 170-200 tons of salt and dust rise into the air and fall on the territory of the Republic of Karakalpakstan. A numbe...A new salty and sandy desert of ca 5 million ha has emerged on the exposed Aral Sea bed. Every year, 170-200 tons of salt and dust rise into the air and fall on the territory of the Republic of Karakalpakstan. A number of experiments have been cond.ucted in order to study the salt tolerance of plants and select drought- and salt-resistant plant species, which show a wide ecological range, to fix quick-sand dunes on the exposed Aral Sea bed. Among the studied species of Calligonum genus C. caput-medusae Schrenk was the most resistant to the saline solution. At the end of the vegetation experiment, the survivability of individuals constituted 44.1% at the concentration of 1.0% of sodium chloride. Artemisiaferganensis Krasch. ex Poljak. and Salsola richteri （Moq.） Kar. ex Litv. showed a good resistance to the concentration of saline solution as high as 150 ram, at which no dried plants were recorded. As the concentration grew to 300 mM, the survivability of Artemisiaferganensis dropped to 40.0% while 66.7 Salsola richteri individuals were developing successfully. An almost similar result was obtained during the experiment on Nitraria schoberi L.. The survivability ofKrascheninnikovia ewersmanniana （Stschegl. ex Losinsk.） Grub. individuals significantly decreased at the concentration of 200 mm （33.4%）, while for Agropyron cristatum the concentration of 300 mm was threshold, at which the survivability of individuals was below 3.3%. The most resistant to the deflation of sands on the exposed bed were Salsola richteri and Calligonum caput-medusae, whose survivability on the sandy dunes was 17%-41%.展开更多
The possibility of cultivation of lndigofera tinctoria L.plants in ecologically degraded and saline lands of the Aral Sea Basin was studied.A new salt-resistant Indigofera plant variety"Feruz-l"was producing...The possibility of cultivation of lndigofera tinctoria L.plants in ecologically degraded and saline lands of the Aral Sea Basin was studied.A new salt-resistant Indigofera plant variety"Feruz-l"was producing by the classic methods of genetics and modem biotechnology.Agro-technology of cultivation as main and secondary culture after wheat was developed and recommended to the farmers of the country.The biotechnology of natural plant pigment indigo extraction has been developed and was recommended for using in different fields of industry:textile,pharmacy-pharmacology,perfume-cosmetic,architectural-decorative and food industry.Quantitative and qualitative HPLC(high pressure liquid chromatography)method of determination of plant natural indigo has been also developed.展开更多
As a result of the Aral Sea shrinkage, the unique freshwater body has given place to a huge bitter-saline lake with an area 3.5 times less, volume 6 times less and water salinity 10 times larger than in 1960, and the ...As a result of the Aral Sea shrinkage, the unique freshwater body has given place to a huge bitter-saline lake with an area 3.5 times less, volume 6 times less and water salinity 10 times larger than in 1960, and the saline desert at the interface between three sand deserts with an area of more than 5 million ha, being unstable ecological zone. The exposed ground is illustrative of arid salt-accumulation, where was created specific type of soil-costal solonchak. The origination of life in the soil of the dried bed starts long before the occurrence of external characteristics. This process can be traced only by studying the microbiological composition of soil. Research in this direction, was conducted in order to determine the microbiological composition of soil for horizons of one typical profile of solonchak. The research objective was to determine microorganism species in the soil on the dried seabed, identify changes in the microorganism community along the soil profile and dependence on duration of the drying process. Additionally, we paid attention to a vegetation effect on the composition of microorganisms. Soil samples were taken along a transect from the sea to the mainland, selected from the different depth of soil profiles taken under or near plant (saxaul). The method Gas chromatography mass-spectrometry was used. Bacteria of the community of microorganisms in different parts of the soil cover on the dried seabed of the Aral Sea and on the mainland belong to five bacterial phyla: Proteobacteria Actinobacteria Firmicutes Bacteroidetes and Deinococcus-Thermus. In general, 59 bacterial species of 43 genera were reconstructed. The total population varied from 105 cells/g to 108 cells/g of the soil. The association Aeromonas hydrophila-Arthrobacter sp. played the key role at the first stages of the soil formation process on the dried seabed of the Aral Sea. This association is followed by salt-resistant Agrobacterium sp. and humus-accumulating Propionibacterium freudenreichii, activity of which is also very important for the formation of the soil cover. The studying properties of the dried seabed cover of both salt composition and microbiological composition made it possible to trace the formation of primary soil on marine sediments with the subsequent formation of desert-type soil.展开更多
The term ‘biological resources' here means a set of organisms that can be used by man directly or indirectly for consumption. They are involved in economic activities and represent an important part of a country&...The term ‘biological resources' here means a set of organisms that can be used by man directly or indirectly for consumption. They are involved in economic activities and represent an important part of a country's raw material potential. Many other organisms are also subject to rational use and protection. They can be associated with true resource species through interspecific relationships. The Caspian and Aral Seas are continental water bodies, giant saline lakes. Both categories of species are represented in the benthic and pelagic communities of the Caspian and Aral Seas and are involved in human economic activities. The most important biological resource of the Caspian Sea and the Aral Sea is their ichthyofauna, represented by both aboriginal species and species introduced by man in the 20 th century. Among invertebrates, the main biological resource of these saline lakes is the brine shrimp A rtemia. The physical state of the Caspian as a water body is relatively stable but its biological resources are very seriously af fected by irrational use. The Aral Sea since the second half of the 20 t h century has experienced catastrophic anthropogenic regression, which has led to the almost complete loss of its biological resources due to salinization. However, thanks to efficacious engineering measures, it has now become possible to preserve its northern part(Small Aral) and rehabilitate it, lowering the salinity to its former state. The result has been the restoration of its fish biological resources. In the southern part of Aral(Large Aral), which turned into a group of separated hypersaline reservoirs, the only resource species currently available is the brine shrimp A rtemia. The main environmental threats for biological resources of the future Caspian and Aral as well as potential solutions are considered.展开更多
Lake monitoring by remote sensing is of significant importance to understanding the lake and ambient ecological and environmental processes. In particular, whether lake water storage variation could predict lake surfa...Lake monitoring by remote sensing is of significant importance to understanding the lake and ambient ecological and environmental processes. In particular, whether lake water storage variation could predict lake surfacial temperature or vice versa has long fascinated the research community, in that it would greatly benefit the monitoring missions and scientific interpretation of the lake change processes. This study attempted to remotely detect the dynamics of the Aral Sea and pursue the relationships between varying lake water storage attributes and surface water temperature by using MODIS LST(Moderate-resolution Imaging Spectroradiometer Land Surface Temperature) 8-day composite products, satellite altimeter data, and actual meteorological measurements. Their associations with lake Surface Water Temperatures(SWT) were then analyzed. Results showed the lake water surface areas and elevations of the North Aral Sea tended to increasing trend from 2001(2793.0 km^2, 13.6 m) to 2015(6997.8 km^2, 15.9 m), while those of the South Aral Sea showed a decreasing trend during 2001(20 434.6 km^2, 3.9 m) and 2015(3256.1 km^2, 0.9 m). In addition, the annual daytime and nighttime lake SWT both decreased in the North Aral Sea, while only the daytime SWT in the South Aral Sea exhibited an increase, indicating a rising deviation of diurnal temperatures in the South Aral Sea during the past 15 yr. Moreover, a lower correlation was found between variations in the daytime SWT and storage capacity in the South Aral Sea(R^2 = 0.33;P < 0.05), no fair correlations were tested between lake water storage and daytime SWT in the North Aral Sea nor between lake water storage and nighttime SWT in either part of the sea. These results implied that climate change, if any at least during the research period, has no significant effects on lake dynamics over the two sectors of the Aral Sea with anthropogenic disturbances. However, climate change and human activities may overlap to explain complex consequences in the lake storage variations. Our results may provide a reference for monitoring the spatiotemporal variations of lakes, increasing understanding of the lake water storage changes in relation to the lake SWT, which may benefit the ecological management of the Aral Sea region, in the effort to face the likely threats from climate change and human activities to the region.展开更多
The Aralkum Desert,arising from the significant reduction of the Aral Sea since the 1960s,is recognized as a prominent contributor to salt-dust storms in Central Asia.This study used SBAS-InSAR technology to monitor g...The Aralkum Desert,arising from the significant reduction of the Aral Sea since the 1960s,is recognized as a prominent contributor to salt-dust storms in Central Asia.This study used SBAS-InSAR technology to monitor ground deformation from wind erosion in the southern Aralkum Desert,analyzing wind-blown sediment subsidence and accumulation.The sensitivity of wind erosion to various influencing factors was further analyzed using the Geodetector model.Results indicate a negative correlation be-tween wind erosion intensity and exposure time.The coastlines of the eastern and western lobes are experiencing the most severe erosion,with ground settlement exceeding 20 mm yr^(-1).Sand-drift ac-tivities exhibit a seasonal pattern,with spring experiencing the most notable absolute deformation.Soil moisture was identified as the primary factor controlling ground deformation,while wind speed was the essential factor leading to the deformation.Based on the time series of ground deformation,the dried Aral Sea basin can be clustered into rapid erosion,slow erosion,stable,slow deposit,and rapid deposit zones,respectively.Finally,an intense dust event on March 22,2020,was used to verify the results derived from the SBAS-InSAR technology.Different from the previous studies,this research provides a more detailed view of wind-blown sediment subsidence and accumulation,moving beyond the concept of the dried Aral Sea basin as a simple source of dust emissions.These findings offer vital insights for the quantitative estimation of dust emissions in the southern Aral Sea basin.展开更多
The Aral Sea crisis is considered one of the most severe ecological tragedies from the 1960s in Central Asia.The reasons for this crisis,especially in the twenty-first century,are still scientific disputes.This study ...The Aral Sea crisis is considered one of the most severe ecological tragedies from the 1960s in Central Asia.The reasons for this crisis,especially in the twenty-first century,are still scientific disputes.This study investigated the relationship between land cover change in the Aral Sea related basins and the Aral Sea crisis from 2000 to 2020 by employing the GlobeLand30 dataset with 30 m resolution.Results showed that the cultivated land in the Aral Sea basin increased by 2,291 km^(2),and 75.4%of it occurred in the region of Karakum Canal,the largest water conservancy project for irrigation in the world.The water surface area of reservoirs increased by 1,183.5 km^(2) during the same period.Coincident with this change,the Aral Sea further shrank from 26,280.8 km^(2) in 2000 to 9,285.2 km^(2) in 2020,mainly occurred in the first decade of the twenty-first century.These imply that the Aral Sea crisis is persistent in the twenty-first century and is likely driven by water competition among different regions within the basin for agricultural irrigation.Strengthening the coordination and cooperation of crossboundary water resource management is still the most important management strategy choice to address the crisis from a broader perspective.展开更多
Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices h...Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2) in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 6233and 3841 km^(2) in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2010s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 25.461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.展开更多
基金supported by the United Kingdom(UK)Darwin Initiative(28-003).
文摘The South Aral Seabed is an extreme dryland ecosystem undergoing rapid transformation yet remains misrepresented or absent in global land cover datasets.Conventional vegetation indices,specifically the Normalized Difference Vegetation Index(NDVI),perform poorly in such environments due to their limited ability to distinguish sparse vegetation from highly reflective saline and sandy soils.This study evaluated the effectiveness of the Modified Soil Adjusted Vegetation Index(MSAVI)for improving land cover classification in the South Aral Seabed and conducted a decadal analysis of land cover change between 2013 and 2023 using Landsat 8 imagery(30 m resolution).A spectral index-based classification framework was developed,combining MSAVI with the Normalized Difference Water Index(NDWI)and Salinity Index 1(SI1)to reduce spectral confusion between vegetation,saline soils,and surface water.The MSAVI-based classification achieved an overall accuracy of 77.96%(Kappa coefficient=0.71),supported by 313 field-collected validation points from 2023.While the multi-index approach enabled finer discrimination of ecologically important classes,particularly separating salt pans from solonchak soils,it resulted in a lower overall accuracy(73.80%),highlighting a trade-off between class separability and classification performance.Land cover change analysis revealed a highly dynamic landscape,with 52.96%of the study area transitioning between classes over the decade.Transformed areas(16,893 km2)exceeded stable zones(15,004 km2),driven primarily by rapid desiccation and salinization.Solonchak soils increased at an annual rate of 5.58%,while surface water bodies declined by 4.83%per year.Concurrently,sparse or distressed vegetation increased by 1.43%annually,reflecting ongoing afforestation efforts.This study provides the first MSAVI-based and medium-resolution land cover baseline for the South Aral Seabed and demonstrates that soil-adjusted vegetation indices are essential for reliable dryland classification where conventional indices fail.The proposed spectral index framework offers a replicable methodology applicable to other global drylands facing similar land degradation and restoration challenges.
文摘The Aral Sea was one of the largest lakes in the world before it started to shrink in the 1960s due to water withdrawal for agricultural irrigation. Precipitation decreased from 9.4 kmin 1960 to 3.2 km3 in 2009, and annual river inflow into the Aral Sea decreased from 31.5 km3 in 1998 to 5.2 km3 in 2009. Comparison on the hydrological data of the Aral Sea between 1960 and 2009 showed the evaporation, water surface area, and water volume decreased by 90%, 80%, and 88%, respectively. This study employs the observed values of water volume, precipitation, runoff, evaporation, and salinity to estimate water volume and salinity from 1960 to 2009, and the efficiency coefficients for predicted water volume and salinity are o.975 and 0.974, respectively. Regression equations calculated from the observed data are used to predict precipitation, runoff, evaporation, and salinity from 20lO to 2021, and the results are then applied in the estimation of water volume and salinity Our estimates suggest that salinity will increase to around 200 g/L and water volume will decrease to around 83 km3 in 2021.
基金supported by the Key R&D Program of Xinjiang Uygur Autonomous Region,China(2022B03021)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20030101)the Tianshan Talent Training Program of Xinjiang Uygur Autonomous Region,China(2022TSYCLJ0011).
文摘The Aral Sea was the fourth largest lake in the world but it has shrunk dramatically as a result of irrational human activities, triggering the "Aral Sea ecological crisis". The ecological problems of the Aral Sea have attracted widespread attention, and the alleviation of the Aral Sea ecological crisis has reached a consensus among the five Central Asian countries(Kazakhstan, Uzbekistan, Tajikistan, Kyrgyzstan, and Turkmenistan). In the past decades, many ecological management measures have been implemented for the ecological restoration of the Aral Sea. However, due to the lack of regional planning and zoning, the results are not ideal. In this study, we mapped the ecological zoning of the Aral Sea from the perspective of ecological restoration based on soil type, soil salinity, surface water, groundwater table, Normalized Difference Vegetation Index(NDVI), land cover, and aerosol optical depth(AOD) data. Soil salinization and salt dust are the most prominent ecological problems in the Aral Sea. We divided the Aral Sea into 7 first-level ecological restoration subregions(North Aral Sea catchment area in the downstream of the Syr Darya River(Subregion Ⅰ);artificial flood overflow area in the downstream of the Aral Sea(Subregion Ⅱ);physical/chemical remediation area of the salt dust source area in the eastern part of the South Aral Sea(Subregion Ⅲ);physical/chemical remediation area of severe salinization in the central part of the South Aral Sea(Subregion Ⅳ);existing water surface and potential restoration area of the South Aral Sea(Subregion Ⅴ);Aral Sea vegetation natural recovery area(Subregion Ⅵ);and vegetation planting area with slight salinization in the South Aral Sea(Subregion Ⅶ)) and 14 second-level ecological restoration subregions according to the ecological zoning principles. Implementable measures are proposed for each ecological restoration subregion. For Subregion Ⅰ and Subregion Ⅱ with lower elevations, artificial flooding should be carried out to restore the surface of the Aral Sea. Subregion Ⅲ and Subregion Ⅳ have severe salinization, making it difficult for vegetation to grow. In these subregions, it is recommended to cover and pave the areas with green biomatrix coverings and environmentally sustainable bonding materials. In Subregion Ⅴ located in the central and western parts of the South Aral Sea, surface water recharge should be increased to ensure that this subregion can maintain normal water levels. In Subregion Ⅵ and Subregion Ⅶ where natural conditions are suitable for vegetation growth, measures such as afforestation and buffer zones should be implemented to protect vegetation. This study could provide a reference basis for future comprehensive ecological management and restoration of the Aral Sea.
基金This study was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA20020101).We also thank for the project"Modern Trends in the Development of Vegetation and Fauna of Ustyurt in the Process of Desertification"(F3MВ-2016-0910183457),which is supported by the Ministry of Innovative Development of the Republic of Uzbekistan.
文摘The gradual shrinkage of the Aral Sea has led to not only the degradation of the unique environments of the Aral Sea,but also numerous and fast developing succession processes in the neighborhood habitats surrounding the sea.In this study,we investigated the vegetative succession processes related to the Aral Sea shrinkage in the Eastern Cliff of the Ustyurt Plateau in Republic of Uzbekistan,Central Asia.We compared the results of our current investigation(2010–2017)on vegetative communities with the geobotany data collected during the 1970s(1970–1980).The results showed great changes in the mesophytic plant communities and habitat aridization as a result of the drop in the underground water level,which decreased atmospheric humidity and increased the salt content of the soil caused by the shrinkage of the Aral Sea.In the vegetative communities,we observed a decrease in the Margalef index(DMg),which had a positive correlation with the poly-dominance index(I-D).The main indications of the plant communities'transformation were the loss of the weak species,the appearance of new communities with low species diversity,the stabilization of the projective cover of former resistant communities,as well as the appearance of a new competitive species,which occupy new habitats.
文摘The increase of irretrievable river water withdrawals and regulation of river flow has a negative effect on the natural regime of the Aral Sea. The Ainu Darya River and the Syr Darya River Basins are the largest irrigated farming areas. Their favorable soil and climatic conditions ensure guaranteed yields of various crops on irrigated lands. Since 1961, for the drastic increase of irretrievable river water withdrawal, mainly for irrigation, the inflow of fiver water into the Aral Sea has started to decrease significantly, accordingly the sea＇s hydrological and hydrochemical regimes disrupted dramatically. The sea level has continued to drop as evaporation exceeds inflow. This negatively transforms the natural environment and worsens socio-economic conditions in Priaralie as a whole, especially in the lower reaches of Amu Darya and Syr Darya, where natural conditions are largely determined by the sea＇s impact. At present, this causes desertification of the nonirrigated zone in the deltas, spreading to new areas as the Aral Sea dries out.
基金supported by the National Natural Science Foundation of China (42230708)the Joint CAS (Chinese Academy of Sciences) & MPG (Max-Planck-Gesellschaft) Research Project (HZXM20225001MI)the Tianshan Talent Project of Xinjiang Uygur Autonomous Region, China (2022TSYCLJ0056)。
文摘The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the Bayesian Estimator of Abrupt change,Seasonal change,and Trend(BEAST)model to detect the historical change points in the variation of the Aral Sea and the Amu Darya River and analyse the causes of the Aral Sea shrinkage during the 1950–2016 period.Further,we applied multifractal detrend cross-correlation analysis(MF-DCCA)and quantitative analysis to investigate the responses of the Aral Sea to the runoff in the Amu Darya River,which is the main source of recharge to the Aral Sea.Our results showed that two significant trend change points in the water volume change of the Aral Sea occurred,in 1961 and 1974.Before 1961,the water volume in the Aral Sea was stable,after which it began to shrink,with a shrinkage rate fluctuating around 15.21 km3/a.After 1974,the water volume of the Aral Sea decreased substantially at a rate of up to 48.97 km3/a,which was the highest value recorded in this study.In addition,although the response of the Aral Sea's water volume to its recharge runoff demonstrated a complex non-linear relationship,the replenishment of the Aral Sea by the runoff in the lower reaches of the Amu Darya River was identified as the dominant factor affecting the Aral Sea shrinkage.Based on the scenario analyses,we concluded that it is possible to slow down the retreat of the Aral Sea and restore its ecosystem by increasing the efficiency of agricultural water use,decreasing agricultural water use in the middle and lower reaches,reducing ineffective evaporation from reservoirs and wetlands,and increasing the water coming from the lower reaches of the Amu Darya River to the 1961–1973 level.These measures would maintain and stabilise the water area and water volume of the Aral Sea in a state of ecological restoration.Therefore,this study focuses on how human consumption of recharge runoff affects the Aral Sea and provides scientific perspective on its ecological conservation and sustainable development.
文摘The greatest environmental disaster in Central Asiathe drying up of the Aral Seahas led to the formation of a new terrain, extending over 2.7 million hectares in Uzbekistan. This newly formed terrain is dynamically developing, with emerging soil formations replacing bottom sediments. This paper analyzes the results of a study on soil formation in the eastern part of the dried-up seabed, focusing on the influence of natural processes occurring there.
基金supported by the Department of Ecology in Kazakh Research Institute of Soil Science and Agrochemistry named after Uspanov,Almaty,Kazakhstan
文摘The effects of human activities on the soil cover transformation in the eastern part of Kazakhstan were investigated during the period of 1956-2008.The results of the research for different soil types in Priaralye indicated that there was 643.3×103 hm2 solonchaks,accounting for 38.5 % of the total area（1670.5×10^3 hm^2） in 2008.Vast areas are occupied with dried lakeshore soil（311.1× 10^3 hm^2）,sandy soils（147.6×10^3 hm^2） and grey-brown desert soils and solonetzes（146.7×10^3 hm^2）.In 2001 the area of solonchak was 755×103 hm2 and decreased to 643.3×10^3 hm^2 in 2008,which due to the shrinkage of the Aral Sea,the areas of marsh and lakeshore solonchaks decreased with the increase of dried bottom of the Aral Sea.The level of soil cover transformation in the modern delta of the Syr-Darya River can be seen from the comparison of the results obtained from the different years in the study area.The area of solonchaks increased by 10×10^3 hm^2 and the area of alluvial-meadow salinizied soils increased by 17.9×10^3 hm^2 during the period of 1956-1969.It means that many non-salinizied soils were transformed into salinizied ones.Striking changes occurred in the structure of soil cover as a result of aridization.So,the researches in1969 significantly determined the areas of hydromorphic soils subjected to desertification（it was not fixed on the map before 1956）.Later,these soils were transformed into takyr-like soils.The area of takyr-like soils increased almost by 3 times for 34 years（from 1956 to 1990）.The long-term soil researches on soil cover transformation in Priaralye have shown that the tendencies of negative processes（salinization and deflation） are being kept and lead to further soil and eco-environment degradation in the region.
文摘A new salty and sandy desert of ca 5 million ha has emerged on the exposed Aral Sea bed. Every year, 170-200 tons of salt and dust rise into the air and fall on the territory of the Republic of Karakalpakstan. A number of experiments have been cond.ucted in order to study the salt tolerance of plants and select drought- and salt-resistant plant species, which show a wide ecological range, to fix quick-sand dunes on the exposed Aral Sea bed. Among the studied species of Calligonum genus C. caput-medusae Schrenk was the most resistant to the saline solution. At the end of the vegetation experiment, the survivability of individuals constituted 44.1% at the concentration of 1.0% of sodium chloride. Artemisiaferganensis Krasch. ex Poljak. and Salsola richteri （Moq.） Kar. ex Litv. showed a good resistance to the concentration of saline solution as high as 150 ram, at which no dried plants were recorded. As the concentration grew to 300 mM, the survivability of Artemisiaferganensis dropped to 40.0% while 66.7 Salsola richteri individuals were developing successfully. An almost similar result was obtained during the experiment on Nitraria schoberi L.. The survivability ofKrascheninnikovia ewersmanniana （Stschegl. ex Losinsk.） Grub. individuals significantly decreased at the concentration of 200 mm （33.4%）, while for Agropyron cristatum the concentration of 300 mm was threshold, at which the survivability of individuals was below 3.3%. The most resistant to the deflation of sands on the exposed bed were Salsola richteri and Calligonum caput-medusae, whose survivability on the sandy dunes was 17%-41%.
文摘The possibility of cultivation of lndigofera tinctoria L.plants in ecologically degraded and saline lands of the Aral Sea Basin was studied.A new salt-resistant Indigofera plant variety"Feruz-l"was producing by the classic methods of genetics and modem biotechnology.Agro-technology of cultivation as main and secondary culture after wheat was developed and recommended to the farmers of the country.The biotechnology of natural plant pigment indigo extraction has been developed and was recommended for using in different fields of industry:textile,pharmacy-pharmacology,perfume-cosmetic,architectural-decorative and food industry.Quantitative and qualitative HPLC(high pressure liquid chromatography)method of determination of plant natural indigo has been also developed.
文摘As a result of the Aral Sea shrinkage, the unique freshwater body has given place to a huge bitter-saline lake with an area 3.5 times less, volume 6 times less and water salinity 10 times larger than in 1960, and the saline desert at the interface between three sand deserts with an area of more than 5 million ha, being unstable ecological zone. The exposed ground is illustrative of arid salt-accumulation, where was created specific type of soil-costal solonchak. The origination of life in the soil of the dried bed starts long before the occurrence of external characteristics. This process can be traced only by studying the microbiological composition of soil. Research in this direction, was conducted in order to determine the microbiological composition of soil for horizons of one typical profile of solonchak. The research objective was to determine microorganism species in the soil on the dried seabed, identify changes in the microorganism community along the soil profile and dependence on duration of the drying process. Additionally, we paid attention to a vegetation effect on the composition of microorganisms. Soil samples were taken along a transect from the sea to the mainland, selected from the different depth of soil profiles taken under or near plant (saxaul). The method Gas chromatography mass-spectrometry was used. Bacteria of the community of microorganisms in different parts of the soil cover on the dried seabed of the Aral Sea and on the mainland belong to five bacterial phyla: Proteobacteria Actinobacteria Firmicutes Bacteroidetes and Deinococcus-Thermus. In general, 59 bacterial species of 43 genera were reconstructed. The total population varied from 105 cells/g to 108 cells/g of the soil. The association Aeromonas hydrophila-Arthrobacter sp. played the key role at the first stages of the soil formation process on the dried seabed of the Aral Sea. This association is followed by salt-resistant Agrobacterium sp. and humus-accumulating Propionibacterium freudenreichii, activity of which is also very important for the formation of the soil cover. The studying properties of the dried seabed cover of both salt composition and microbiological composition made it possible to trace the formation of primary soil on marine sediments with the subsequent formation of desert-type soil.
基金supported by the program of the Presidium of the Russian Academy of Sciences“No.41.Biodiversity of natural systems and biological resources of Russia”by the theme of the State assignment for 2017–2019“AAAA-A17-117030310206-6
文摘The term ‘biological resources' here means a set of organisms that can be used by man directly or indirectly for consumption. They are involved in economic activities and represent an important part of a country's raw material potential. Many other organisms are also subject to rational use and protection. They can be associated with true resource species through interspecific relationships. The Caspian and Aral Seas are continental water bodies, giant saline lakes. Both categories of species are represented in the benthic and pelagic communities of the Caspian and Aral Seas and are involved in human economic activities. The most important biological resource of the Caspian Sea and the Aral Sea is their ichthyofauna, represented by both aboriginal species and species introduced by man in the 20 th century. Among invertebrates, the main biological resource of these saline lakes is the brine shrimp A rtemia. The physical state of the Caspian as a water body is relatively stable but its biological resources are very seriously af fected by irrational use. The Aral Sea since the second half of the 20 t h century has experienced catastrophic anthropogenic regression, which has led to the almost complete loss of its biological resources due to salinization. However, thanks to efficacious engineering measures, it has now become possible to preserve its northern part(Small Aral) and rehabilitate it, lowering the salinity to its former state. The result has been the restoration of its fish biological resources. In the southern part of Aral(Large Aral), which turned into a group of separated hypersaline reservoirs, the only resource species currently available is the brine shrimp A rtemia. The main environmental threats for biological resources of the future Caspian and Aral as well as potential solutions are considered.
基金Under the auspices of State Special Funds for Research Infrastructure of China(No.2015FY110500)National Natural Science Foundation of China(No.41730104)
文摘Lake monitoring by remote sensing is of significant importance to understanding the lake and ambient ecological and environmental processes. In particular, whether lake water storage variation could predict lake surfacial temperature or vice versa has long fascinated the research community, in that it would greatly benefit the monitoring missions and scientific interpretation of the lake change processes. This study attempted to remotely detect the dynamics of the Aral Sea and pursue the relationships between varying lake water storage attributes and surface water temperature by using MODIS LST(Moderate-resolution Imaging Spectroradiometer Land Surface Temperature) 8-day composite products, satellite altimeter data, and actual meteorological measurements. Their associations with lake Surface Water Temperatures(SWT) were then analyzed. Results showed the lake water surface areas and elevations of the North Aral Sea tended to increasing trend from 2001(2793.0 km^2, 13.6 m) to 2015(6997.8 km^2, 15.9 m), while those of the South Aral Sea showed a decreasing trend during 2001(20 434.6 km^2, 3.9 m) and 2015(3256.1 km^2, 0.9 m). In addition, the annual daytime and nighttime lake SWT both decreased in the North Aral Sea, while only the daytime SWT in the South Aral Sea exhibited an increase, indicating a rising deviation of diurnal temperatures in the South Aral Sea during the past 15 yr. Moreover, a lower correlation was found between variations in the daytime SWT and storage capacity in the South Aral Sea(R^2 = 0.33;P < 0.05), no fair correlations were tested between lake water storage and daytime SWT in the North Aral Sea nor between lake water storage and nighttime SWT in either part of the sea. These results implied that climate change, if any at least during the research period, has no significant effects on lake dynamics over the two sectors of the Aral Sea with anthropogenic disturbances. However, climate change and human activities may overlap to explain complex consequences in the lake storage variations. Our results may provide a reference for monitoring the spatiotemporal variations of lakes, increasing understanding of the lake water storage changes in relation to the lake SWT, which may benefit the ecological management of the Aral Sea region, in the effort to face the likely threats from climate change and human activities to the region.
基金supported by the Basic Frontier Project of Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences(No.E3500201)Xinjiang Tianshan Talent Program(No.2022TSYCLJ0002)the Project of the Youth Interdisciplinary Innovation Team of the State Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands(No.E4500125).
文摘The Aralkum Desert,arising from the significant reduction of the Aral Sea since the 1960s,is recognized as a prominent contributor to salt-dust storms in Central Asia.This study used SBAS-InSAR technology to monitor ground deformation from wind erosion in the southern Aralkum Desert,analyzing wind-blown sediment subsidence and accumulation.The sensitivity of wind erosion to various influencing factors was further analyzed using the Geodetector model.Results indicate a negative correlation be-tween wind erosion intensity and exposure time.The coastlines of the eastern and western lobes are experiencing the most severe erosion,with ground settlement exceeding 20 mm yr^(-1).Sand-drift ac-tivities exhibit a seasonal pattern,with spring experiencing the most notable absolute deformation.Soil moisture was identified as the primary factor controlling ground deformation,while wind speed was the essential factor leading to the deformation.Based on the time series of ground deformation,the dried Aral Sea basin can be clustered into rapid erosion,slow erosion,stable,slow deposit,and rapid deposit zones,respectively.Finally,an intense dust event on March 22,2020,was used to verify the results derived from the SBAS-InSAR technology.Different from the previous studies,this research provides a more detailed view of wind-blown sediment subsidence and accumulation,moving beyond the concept of the dried Aral Sea basin as a simple source of dust emissions.These findings offer vital insights for the quantitative estimation of dust emissions in the southern Aral Sea basin.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA20100104]the National Natural Science Foundation of China[grant number 41988101],[grant number 42071421].
文摘The Aral Sea crisis is considered one of the most severe ecological tragedies from the 1960s in Central Asia.The reasons for this crisis,especially in the twenty-first century,are still scientific disputes.This study investigated the relationship between land cover change in the Aral Sea related basins and the Aral Sea crisis from 2000 to 2020 by employing the GlobeLand30 dataset with 30 m resolution.Results showed that the cultivated land in the Aral Sea basin increased by 2,291 km^(2),and 75.4%of it occurred in the region of Karakum Canal,the largest water conservancy project for irrigation in the world.The water surface area of reservoirs increased by 1,183.5 km^(2) during the same period.Coincident with this change,the Aral Sea further shrank from 26,280.8 km^(2) in 2000 to 9,285.2 km^(2) in 2020,mainly occurred in the first decade of the twenty-first century.These imply that the Aral Sea crisis is persistent in the twenty-first century and is likely driven by water competition among different regions within the basin for agricultural irrigation.Strengthening the coordination and cooperation of crossboundary water resource management is still the most important management strategy choice to address the crisis from a broader perspective.
基金supported by the Key Program of National Natural Science Foundation of China(Grant No.42230708)the Strategic Priority Research Program of the Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road(Grant No.XDA20060303)the K.C.Wong Education Foundation(Grant No.GJTD-2020-14)。
文摘Various investigations have been conducted to analyze the water-coverage area of the Aral Sea and the Aral Sea Basin(ASB). However, the investigations incorporated considerable uncertainty and the used water indices had misclassification problem, which made different research groups present different results. Thus we first ascertain the boundaries of the ASB, the Syr and Amu river basins as well as their upper, middle and lower reaches. Then a four-band index for both liquid and solid water(ILSW) is proposed to address the misclassification problems of the classic water indices. ILSW is calculated by using the reflectance values of the green, red, near infrared, and thermal infrared bands, which combines the normalized difference water index(NDWI) and land surface temperature(LST) together. Validation results show that the ILSW water index has the highest accuracy by far in the Aral Sea Basin. Our results indicate that annual average decline of the water-coverage area was 963 km^(2) in the southern Aral Sea, whereas the northern Aral Sea has experienced little change. In the meanwhile, permanent ice and snow in upper reach of ASB has retreated considerably. Annual retreating rates of the permanent ice and snow were respectively 6233and 3841 km^(2) in upper reaches of Amu river basin(UARB) and Syr river basin(USRB). One of major reasons is that climate has become warmer in ASB. The climate change has caused serious water deficit problem. The water deficit had an increasing trend since the 1990s and its increasing rates was 3.778 billion m^(3) yearly on average. The total water deficit was 76.967 billion m^(3) on average in the whole area of ASB in the 2010s. However, up reaches of Syr river basin(USRB), a component area of ASB, had water surplus of 25.461 billion m^(3). These conclusions are useful for setting out a sustainable development strategy in ASB.
