Aral Sea Basin
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PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12623
Author(s):  
Chao liang Chen ◽  
Xi Chen ◽  
Jing Qian ◽  
Zengyun Hu ◽  
Jun Liu ◽  
...  

Intense human activities in the Aral Sea Basin have changed its natural distribution of land use. Although they provide certain economic benefits, these anthropogenic influences have led to the rapid shrinkage of the Aral Sea, severely affecting the region’s ecosystem. However, the spatiotemporal variability of the Aral Sea Basin’s Ecosystem Service Values (ESVs) is not well understood. In this study, we used 300-meter resolution land use maps from 1995, 2005, and 2015 and the Patch-generating Land Use Simulation (PLUS) model to predict the future land use patterns of the Aral Sea Basin in 2025. Simultaneously, we divided the Aral Sea Basin into three regions (upstream, midstream, and downstream) and evaluated the dynamic responses of their ESVs to Land Use and Land Cover (LULC) changes. The changes in the types of ecosystem services provided by the Aral Sea Basin, their trade-off, and synergistic relationships were analyzed by weighting their associations. The results showed that from 1995 to 2025, the grassland, urban, and cropland areas in the Aral Sea Basin will expand rapidly, while the areas covered by water bodies will shrink rapidly, causing a total loss of 31.97 billion USD. The downstream loss of 27.79 billion USD of the total amount is mainly caused by the conversion of water bodies to bare land. The ESVs of the middle region will increase by 6.81 billion USD, mainly due to the large amount of water extracted from the Amu Darya and Syr Darya Rivers in the middle regions of the Aral Sea Basin that are used to reclaim cultivated land and expand urban areas. The ESVs and areas experiencing land use changes in the upper regions are relatively small. At the same time, our results show that biodiversity, food production, and water regulation are the major ecosystem service functions, and account for 79.46% of the total ESVs. Of the ecosystem service relationships in the Aral Sea Basin, synergy accounts for 55.56% of the interactions, with a fewer amount of trade-off exchanges. This synergy mainly exists in the relationships involving water regulation, waste treatment and recreation, and culture and tourism. We propose protection measures that will coordinate eco-environmental protection efforts with socioeconomic development in the region in order to achieve the United Nations’ sustainable development goals.


2021 ◽  
pp. 229-243
Author(s):  
Michael Groll ◽  
Christian Opp ◽  
Oleg Semenov ◽  
Gulnura Issanova ◽  
Alexander Shapov

Author(s):  
Alexander S. Izhitskiy ◽  
Georgiy B. Kirillin ◽  
Igor V. Goncharenko ◽  
Abilgazy K. Kurbaniyazov ◽  
Peter O. Zavialov
Keyword(s):  
Aral Sea ◽  

2021 ◽  
Vol 9 ◽  
Author(s):  
Timur Berdimbetov ◽  
Zhu-Guo Ma ◽  
Sherly Shelton ◽  
Sana Ilyas ◽  
Sahibjamal Nietullaeva

Land degradation is one of the critical ecological issue in the Aral Sea Basin (ASB). This study investigates land degradation in ASB during 1982–2015 using the Normalized Difference Vegetation Index (NDVI) as a proxy. The residual trend (RESTREND) for temperature, precipitation, soil moisture adjusted NDVI has been applied to identify the land degradation in ASB and quantify the contribution of climate factors such as temperature and rainfall. In addition, a binary logistic regression model is adopted to assess the contributions of land transition, socio-economic, and topographical conditions on land degradation. Based on RESTREND, the relative contribution of precipitation (30.2%), soil moisture (23%), and temperature (11.4%) indicates that precipitation is one of the main driving factors of land degradation. The results further revealed that 36.5% of ASB is degraded, which is mostly concentrated in the lower part of the ASB. In contrast, 33.2% of ASB depicts land improvement, especially in the upper part of the basin. According to the land transition assessment, 66.6% of the water area and 11.68% of forest converted to barren land and shrubland during the study period, respectively. The binary logistic regression model demonstrated water and forest area transitions into shrubland and barren land as the major contributors of contemporary land degradation in ASB. Cropland recorded a net increment by 2.69% of its initial area, and the abandoned cropland converted to shrubland and barren lands that negatively impacted land cover change. This in-depth analysis of land degradation can assist in designing pragmatic policy interventions for implementing land restoration plans in the area.


2021 ◽  
Author(s):  
Jing He ◽  
Yang Yu ◽  
Lingxiao Sun ◽  
Haiyan Zhang ◽  
Ireneusz Malik ◽  
...  

Abstract The Aral Sea started shrinking since the 1960s due to natural factors and human activities; however, the relationship between land cover change and ecosystem services (ES) in the Aral Sea basin has not been fully studied. To analyze and explore the spatiotemporal variation characteristics of ecosystem service values (ESVs) in this region, we used the European Space Agency CCI Global Land Cover product with a spatiotemporal resolution of 300 × 300 m and the annual scale. The land use data of 1993, 1998, 2003, 2008, 2013, and 2018 in the study area were extracted, the study area’s ESV in the corresponding years was calculated, and the temporal and spatial evolution characteristics were analyzed. Additionally, the change rate and sensitivity were analyzed. The results revealed that the area of urban land, bare land, grassland, wetland, and cropland in the Aral Sea basin increased from 1993 to 2018; water body and forestland decreased. The integrated value of water bodies, cropland, and grassland ES accounted for more than 96% of the total ESV; the change rate of land use types differed. Urban land and water changed the fastest; cultivated land, woodland, grassland, and wetland changed the slowest. From 1993 to 2018, the total ESV of the Aral Sea basin decreased from 455.10 to 414.56 billion (Overall decrease = − 8.91%). The ESV study shows that the water area decreased sharply from 1993 to 2018, resulting in a loss of USD 46.84 billion. Biodiversity, food production, and water regulation were the main ES, accounting for 78.5% of the total ESV. The ESV of the Aral Sea basin declined from 1993 to 2018, and significant differences were observed among its regions. Some regions should thus focus on this aspect. A close correlation was observed between the ESV and land use. Hence, effective land use policies can control the expansion of cropland; protect water bodies, ecological environments, grassland, and forestland; and promote a more sustainable ecosystem.


2021 ◽  
Vol 13 (15) ◽  
pp. 2923
Author(s):  
Xuewen Yang ◽  
Ninglian Wang ◽  
Qian Liang ◽  
An’an Chen ◽  
Yuwei Wu

Assessing the impacts of human activities on the variations in terrestrial water storage (TWS) is essential for water resource management, particularly in regions like the Aral Sea Basin which suffers from severe water scarcity. In this study, the variations in TWS anomalies (TWSA) of the Aral Sea Basin during the period of April 2002 to June 2017 were analyzed using Gravity Recovery and Climate Experiment (GRACE) data and the Global Land Data Assimilation System (GLDAS) Noah model outputs. The impacts of human activities on TWS variations were further quantified through the variations in TWS components and the comparison of TWS obtained from GRACE and GLDAS. The results indicate that TWSA of the entire Aral Sea Basin derived from GRACE experienced a significant decreasing trend of 4.12 ± 1.79 mm/year (7.07 ± 3.07 km3/year) from 2002 to 2017. Trends in individual TWS components indicate that the reduction in TWS of the Aral Sea Basin was primarily attributed to surface water loss, followed by groundwater depletion, which account for ~53.16% and 11.65 ± 45.39 to 42.48 ± 54.61% of the total loss of TWS, respectively. Precipitation (P) and evapotranspiration (ET) both exhibited increasing trends, indicating that ET played a dominant role in TWS depletion from the perspective of water balance. The variations in ET and TWS induced by human activities contributed ~45.54% and ~75.24% to those in total ET and TWS of the Aral Sea Basin, respectively.


2021 ◽  
Vol 9 (7) ◽  
pp. 1448
Author(s):  
Lei Gao ◽  
Jinbiao Ma ◽  
Yonghong Liu ◽  
Yin Huang ◽  
Osama Abdalla Abdelshafy Mohamad ◽  
...  

Endophytes associated with halophytes may contribute to the host’s adaptation to adverse environmental conditions through improving their stress tolerance and protecting them from various soil-borne pathogens. In this study, the diversity and antifungal activity of endophytic bacteria associated with halophytic samples growing on the shore of the western Aral Sea in Uzbekistan were investigated. The endophytic bacteria were isolated from the nine halophytic samples by using the culture-dependent method and identified according to their 16S rRNA gene sequences. The screening of endophytic bacterial isolates with the ability to inhibit pathogenic fungi was completed by the plate confrontation method. A total of 289 endophytic bacterial isolates were isolated from the nine halophytes, and they belong to Firmicutes, Actinobacteria, and Proteobacteria. The predominant genera of the isolated endophytic bacteria were Bacillus, Staphylococcus, and Streptomyces, accounting for 38.5%, 24.7%, and 12.5% of the total number of isolates, respectively. The comparative analysis indicated that the isolation effect was better for the sample S8, with the highest diversity and richness indices. The diversity index of the sample S7 was the lowest, while the richness index of samples S5 and S6 was the lowest. By comparing the isolation effect of 12 different media, it was found that the M7 medium had the best performance for isolating endophytic bacteria associated with halophytes in the western Aral Sea Basin. In addition, the results showed that only a few isolates have the ability to produce ex-enzymes, and eight and four endophytic bacterial isolates exhibited significant inhibition to the growth of Valsa mali and Verticillium dahlia, respectively. The results of this study indicated that halophytes are an important source for the selection of microbes that may protect plant from soil-borne pathogens.


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