Vegetation change and ecological quality of the Loess Plateau (LP) are directly related to ecological protection and high-quality development of the Yellow River Basin. Based on LP ecological zoning and multisource remote sensing data, we analyzed vegetation change and its relationship with climate, terrestrial water storage (TWS), and land use/cover change from 2000 to 2020, using the normalized difference vegetation index (NDVI), fraction of vegetation cover (FVC), and net primary productivity (NPP). And ecological environmental quality was evaluated based on the remote sensing ecological index (RSEI). The results showed that the spatial distribution pattern of NDVI, FVC and NPP decreased from southeast to northwest in the LP as a whole. Vegetation in the LP recovered significantly, and NDVI, FVC, and NPP showed significant increases of 35.66%, 34%, and 54.69%, respectively. The average NDVI and FVC in the earth–rocky mountainous region and river valley plain region (Area D) were the highest, but the growth rate was the slowest. The average NDVI, FVC, and growth rates in the loess hilly and gully regions (Area B) were slightly higher than those in the loess sorghum gully region (Area A). The average NDVI, FVC, and NPP in the sandy land and agricultural irrigation regions (Area C) were the lowest but showed significant increase. RSEI in most LP areas changed from poor to medium, increasing by 43.45%. Precipitation is the basic factor affecting vegetation cover pattern, with the increase (40.79 mm/10a) promoting vegetation restoration in the LP. Vegetation restoration lost much TWS (−0.6 mm/month), and Area D had the highest average NDVI, FVC, and NPP but the largest TWS loss. Anthropogenic land use/cover change (LUCC) (decrease in cultivated land and unused land; increase in forest, grassland, and construction land) is the primary factor affecting LP vegetation change. This study provides a scientific reference for further vegetation restoration in the LP.

The Tarim River Basin in Xinjiang, China, has a typical desert riparian forest ecosystem. Analysis of the resilience of this type of ecosystem under extreme drought conditions and ecological rehabilitation projects could provide a theoretical basis for understanding ecosystem stability and resistance, and provide new ecological rehabilitation measures to improve ecosystem resilience. We employed a quantitative framework to assess net primary productivity (NPP) resilience, emphasizing four aspects of NPP dynamics: NPP, NPP stability, NPP resistance, and maximum NPP potential. We compared ecosystem resilience across four time periods: before the implementation of ecological rehabilitation projects (1990–2000), during construction and partial implementation of ecological rehabilitation projects (2001–2012), during the initial project stage of ecological rehabilitation (2013–2015), and during the late project stage of ecological rehabilitation (2016–2018). There are three main finding of this research. (1) Mean NPP was increased significantly from 2013 and was decreased from 2016, especially in the main stream of the Tarim River and in the basins of eight of its nine tributary rivers. (2) Ecosystem resilience in 2013–2018 was greater than in 1990–2012, with the greatest NPP stability, mean NPP and NPP resistance, especially in part one of the river basin (the Aksu River, the Weigan-Kuche River, the Dina River, the Kaidu-Konqi River, and the main stream of the Tarim River). Ecosystem resilience in 2001–2012 was lowest when compared to 1990–2000 and 2013–2018, with lowest mean NPP, NPP stability, NPP resistance and maximum NPP potential, particularly in part two of the river basin (the Kashigr River, the Yarkand River and the Hotan River basins). Therefore, part one was most affected by ecological restoration projects. When 2013–2018 was divided into two distinct stages, 2013–2015 and 2016–2018, resilience in the latter stage was the lowest, with lowest mean NPP, NPP resistance and maximum NPP potential, especially in the main stream of the Tarim River. This may be due to unreasonable water conveyance in 2014–2015. (3) Ecological resilience has increased significantly in 2013–2015 after the implementation of ecological water transfer projects, river regulation, and natural vegetation enclosure projects. Ecosystem resilience could continue to increase even more in the future with the continued implementation of reasonable ecological water transfer projects.

Taitema Lake, located in the lower reaches of the Tarim River and the Cherchen River, is one of the most important ecological barriers in Ruoqiang County. The amount of water in Taitema Lake plays an important role in maintaining a healthy cycle within the ecosystem, curbing sandstorms, and improving salinization and desertification. The aim of this study was to reasonably determine the volume of ecological water conveyance by calculating the ecological water demand. We systematically analyzed the spatial and temporal variation characteristics of Taitema Lake during 21 ecological water conveyance processes from 2000 to 2020. The results showed that the area of Taitema Lake increased at a rate of 144% per year because of the Ecological Water Conveyance Project (EWCP). The areas of water in dry, normal, and high flow years were 30.35, 57.76, and 103.5 km², respectively. The corresponding ecological water demand was 1.58 × 10⁸, 3.09 × 10⁸, and 5.66 × 10⁸ m³, respectively. We calculated that the Cherchen River and the Tarim River carried 0.87 × 10⁸–3.11 × 10⁸ m³ and 0.71 × 10⁸–2.55 × 10⁸ m³ of water, respectively, under different inflow frequencies. This study has significance as a reference for estimates of the ecological water demand of terminal lakes under the condition of artificial water transport in arid inland river basins, and provides the basis for the rational allocation of water resources in the Tarim River Basin.

Under drought stress, desert riparian forest plants are highly self-regulating and have their own unique water use and regulation strategies, which can respond positively in several aspects such as physiology, ecology, and individual phenotypes when coping and adapting to the stresses brought by external environmental changes. In addition, as an important component of arid zone ecosystems, desert riparian forest plants maintain the cycling process of energy and material in desert areas. Therefore, it is of great ecological value to study the role played by desert riparian forest plants in desertification control and biodiversity conservation in arid zones. The purpose of this study is to provide basic data and scientific basis for the conservation, and restoration of desert riparian forests in the inland river basin of arid zone. In this paper, the physiological and ecological responses of desert riparian plants under drought stress were analyzed by reviewing the literature and focusing on the key scientific issues such as drought avoidance mechanisms, water use, and water redistribution, and the relationship between interspecific water competition and resource sharing of desert riparian plants. The results showed that: (1) In the inland river basin of arid zone, desert riparian plants show a mutual coordination of increasing soluble sugars, proline, malondialdehyde (MDA), and decreasing peroxidase (POD), to form a unique drought avoidance mechanism, and improve their drought tolerance by changing leaf stomatal conductance resulted from regulating abscisic acid (ABA) and cytokinin (CTK) content. (2) Desert riparian forest plants have their own unique water use and regulation strategies. When the degree of drought stress increased, Populus euphratica enhanced the water flow of dominant branches by actively sacrificing the inferior branches to ensure and improve the overall survival chances of the plant, while Tamarix ramosissima weaken hydraulic conductance, and increase subsurface material inputs by reducing plant height to cope with drought stress. (3) The root systems of desert riparian plants have hydraulic uplift and water redistribution functions, and, in the hydraulic uplift process of P. euphratica and T. ramosissima root systems, there is a possibility of assisting with other species in water utilization and the existence of a resource sharing mechanism.

Hydrological connectivity directly affects aquatic ecological processes, water environment and wetland ecological security, which is essential to the stability of arid ecosystems. However, the mechanism between hydrological connectivity and water-related environment has not been revealed completely. To address these issues, we use a landscape connectivity approach to assess the connectivity of water patches for analyzing the hydrological connectivity of the Bosten Lake Basin (BLB), as well as its response to human activities and climate change, based on the Joint Research Centre (JRC) global surface water dataset. It shows that the integral index of connectivity (IIC) of the BLB is low (ranging from 0 to 0.2) from 1990 to 2019, with an increasing interannual trend. The connectivity is higher in wet periods and in oases compared with dry periods and high-altitude mountain regions. Correlation and regression analyses indicate that hydrological connectivity has a strong correlation (r > 0.5, p ≤ 0.05) with water area and water level. The interannual and seasonal trends of eight hydrochemical indices in the Bosten Lake have been investigated to systematically elaborate the complex relationships between hydrological connectivity and water quality in the BLB. Results indicated that better hydrological connectivity can improve water quality, and the minimum of pollutants were observed in high hydrological connectivity period, covering approximately 75% of the high-water quality period. These findings could provide scientific support for the water management in the BLB.