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Abstract The Aral Sea, located in Central Asia, has undergone significant reduction in surface area owing to the combined impacts of climate change and human activities. This reduction has led to a regional ecological crisis and profound repercussions on ecosystem services. Investigating the spatiotemporal variations and synergistic trade-offs of ESs in the Aral Sea basin is crucial for fostering the integrated development of the region’s socioeconomic ecology. This study utilizes the Future Land-Use Simulation and InVEST models to analyze future land-use scenarios, integrating CMIP6 projections to assess the quality of four key ecosystem services: water production, soil conservation, carbon storage, and habitat quality over two timeframes: the historical period (1995–2020) and the projected future (2021–2100). Employing Spearman correlation, the study explores the trade-offs and synergies among these ecosystem services. Findings reveal that the primary forms of land-use change in the Aral Sea basin are the reduction in water area (− 49.59%) and the rapid expansion of urban areas (+ 504.65%). Temporally, habitat quality exhibits a declining trend, while carbon storage shows an increasing trend, and water production and soil retention fluctuate initially decreasing and then increasing. Spatially, water production and carbon storage demonstrate an increasing trend from the northwest to the southeast. Habitat quality exhibits a higher spatial pattern in the southeast and south, contrasting with lower spatial patterns in the north and west. Low-level soil conservation is predominantly distributed in the northwest, while medium to low-level soil conservation is prevalent in the east of the basin. The trade-off and synergy analysis indicates that between 1995 and 2020, a trade-off relationship existed between carbon storage and habitat quality and water production, whereas synergies were observed between soil conservation and carbon storage, water production and habitat quality, and soil conservation. The correlation between water production and soil conservation emerges as the strongest, whereas the correlation between carbon storage and habitat quality appears to be the weakest. The dynamic spatiotemporal changes, trade-offs, and collaborative relationships of ESs constitute major aspects of ecosystem service research, holding substantial implications for the effective management of the regional ecological environment.

Water scarcity is an important factor limiting agricultural development in arid areas. Clarifying and evaluating the current situation of water resources in arid regions is helpful for decision-makers in the rational use of water resources. This study takes a typical arid region located at the edge of Taklamakan Desert-Hotan region as the study area. The water footprint (WF) of the Hotan region was calculated based on 20 years of data information from 2000–2019. An evaluation system was established using four aspects of the WF: structural indicators, efficiency indicators, ecological safety indicators, and sustainability indicators. The results show that the WF of the study area is mainly dominated by blue water consumption, with a proportion of 65.74%. The WF of crop production is larger than that of livestock production. The produced WF of grain crops is the highest of all products with a share of 44.21%. The increase in the local agricultural WF reached 53.18% from 2000 to 2019, but it was still lower than the amount of water available for agriculture. The evaluation results indicated that the region’s WF import dependency is lower than the global level, with an annual average self-sufficiency rate of 91.13% and an increase of 878.95% in the WF economic efficiency index. The agricultural WF produced in Hotan is exported in the form of trade, but the quantitative contribution is small and does little to relieve water stress in other regions. The agricultural water consumption was still within the range of local water resources that could be carried but only 6 years of sustainable water use, and the future development was not optimistic. With the ratio of produced WF to available water resources maintained at about 58%, the local available water resources should be above 43.21 × 108 m3 to initially ensure the sustainable use of water resources. There were 12 drought years in the study period, which are prone to droughts and high disaster levels. The drought-water scarcity systems behaved in three phases: 2000–2011 (uncoordinated level), 2012–2015 (transitional phase), and 2016–2019 (coordinated level). Water scarcity threatened by drought reduced. The occurrence of meteorological droughts was more related to natural factors while the changes in WF were mainly driven by socio-economic elements such as human activities.

The temporal variability and abrupt change analysis of temperature and precipitation in Turpan was investigated and examined based on a monthly data set of temperature, precipitation and drought indices (1960–2019) from three meteorological stations over the study area. The Yamamoto method, Mann–Kendall test, Standardized Precipitation Index (SPI), Standardized Precipitation Evaporation Index (SPEI), and Reconnaissance Drought Index (RDI) were applied to reveal temperature, precipitation and drought indices trends in their annual volumes. The conclusions were as follows: (1) in the past 60 years, the annual average temperature in the Turpan region has increased at a rate of 0.33 °C·(10a)−1. Whereas the temperature has accelerated since the 1980s, the annual average minimum temperature has increased more than the annual average maximum temperature, and the temperature difference between winter and summer has increased since the 1990s. (2) The inter-annual, inter-decadal and normal value changes in precipitation in the Turpan region and its three meteorological stations indicated a decreasing trend during 1960–2019. Though the normal value of summer and autumn precipitation decreased and increased as a whole, the normal values of spring, summer, winter and annual precipitation in the Turpan region displayed downward trends. (3) Abrupt changes in temperature were observed in the mid-1990s, and abrupt changes in precipitation were not obvious. (4) The SPI and RDI responded quickly to precipitation and temperature, and the overall characteristics of dry and wet trend changes were consistent. When the SPEI considered the combined effect of temperature and precipitation, the SPI and SPEI are better correlated, and the SPI and RDI are better correlated than the SPEI and RDI. On the whole, the occurrence of drought has obvious regional and seasonal characteristics. These conclusions not only provide scientific data for sustainable development in Turpan but also offer scientific information to further understand the trends and periodicity of climate change and drought conditions in hyper-arid regions around the world.

Recent studies on China's arid and semi-arid regions, particularly the Tarim River Basin (TRB), have shown an increase in the intensity and frequency of extreme weather events. This research examines the link between meteorological droughts, as measured by the Standardized Precipitation Evapotranspiration Index (SPEI), and hydrological droughts, as indicated by the Standardized Runoff Index (SRI) and the Standardized Terrestrial Water Storage Index (STI), over various time scales. Historical data indicate that SPEI drought frequency (DF) was 14.3–21.9%, with prevalent events in the northern oases. SRI DF ranged from 9.0% to 35.8%, concentrated around the Taklamakan and Kumtag Deserts, while STI DF varied between 4.4% and 32.7%, averaging 15% basin-wide. Future projections show an increased DF of SPEI in deserts and a decrease in oases; SRI DF decreased in deserts but increased in oases. STI changes were more moderate. The study also found a higher risk of drought progression from SPEI to SRI in the southwestern and northeastern oases, exceeding 50% probability, while central and eastern TRB had lower risks. The western TRB and inner Taklamakan Desert faced higher risks of SPEI to STI progression, with probabilities over 45%, in contrast to the lower risks in the eastern and central oases. The concurrence of SRI/STI with moderate to extreme SPEI droughts led to a higher probability and area of SRI/STI droughts, whereas consistent SPEI types showed a reduced induced probability and extent of SRI/STI droughts. This study enhances the understanding of drought propagation from meteorological to hydrological droughts in the TRB and contributes to the prevention of hydrological drought to a certain extent. [ABSTRACT FROM AUTHOR]

The eco-environment provides various spaces, conditions, and resources for human development, and their quality is a significant factor affecting sustainable development in a region. Most drylands face environmental fragility due to problems such as infertile land, scarce suitable living space, and a lack of resources. Therefore, investigating the temporal and spatial changes in the eco-environment of drylands is vital to developing them sustainably. This paper takes Hetian, which is located in the Tarim Basin of Western China and has typical features of an arid (or a hyper-arid) region, as the research area. The ecological index (EI) was used to construct a comprehensive ecological evaluation system, and five sub-indices (the biological richness index, vegetation coverage index, water network denseness index, land stress index, and pollution load index) were calculated to identify the quality and changes in the eco-environment of Hetian in 1995, 2009, and 2018. The results show that, from 1995 to 2018, the EI in Hetian showed a continuous downward trend (from 24.76 to 16.32), representing a change (ΔEI) of −8.44; this indicates significant deterioration in the quality of the local eco-environment. Large fluctuations in the EI also suggests that the environment in Hetian is very sensitive. In addition, the results revealed a degradation of Hetian, which includes a hyper-arid region.

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