The nitrogen deposition process, as an important phenomenon of global climate change and an important link in the nitrogen cycle, has had serious and far-reaching impacts on grassland ecosystems. This study aimed to investigate the survival adaptation strategies of plants of different functional groups under nitrogen deposition, and the study identified the following outcomes of differences in biomass changes by conducting in situ simulated nitrogen deposition experiments while integrating plant nutrient contents and soil physicochemical properties: (1) nitrogen addition enhanced the aboveground biomass of grassland communities, in which Poaceae were significantly affected by nitrogen addition. Additionally, nitrogen addition significantly influenced plant total nitrogen and total phosphorus; (2) nitrogen addition improved the plant growth environment, alleviated plant nitrogen limitation, and promoted plant phosphorus uptake; and (3) there was variability in the biomass responses of different functional groups to nitrogen addition. The level of nitrogen addition was the primary factor affecting differences in biomass changes, while nitrogen addition frequency was an important factor affecting changes in plant community structure.

Nitrogen inputs exert significant impacts on plant species composition and ecosystem stability within alpine grasslands. The exploration of leaf functional traits holds great potential in uncovering plants’ adaptive strategies and competitive edges, and is pivotal in comprehending the ramifications of nitrogen inputs on biodiversity. In this study, the Bayanbulak grassland was selected as the research subject to investigate the impact of nitrogen addition on leaf functional traits of different plant functional groups. Specifically, various gradients of nitrogen addition were established to observe changes in leaf dry matter content (LDMC) and leaf area (LA) among three distinct plant functional groups. Furthermore, structural equation modeling (SEM) was employed to analyze the pathways through which nitrogen addition influenced the LDMC of these plant functional groups. The results were as follows: (1) LA and leaf length (LL) of Poaceae changed significantly (p < 0.05) under different N addition gradients, and leaf nutrient contents of Poaceae, Rosaceae and Fabaceae showed significant changes under different N addition gradients. (2) Pearson correlation analyses showed that total nitrogen (TN), total carbon (TOC) and leaf width (LW) of Rosaceae leaves had a significant positive correlation, and the TOC and total phosphorus (TP) of Fabaceae leaves showed a significant negative correlation. (3) SEM of the three plant functional groups showed direct and indirect effects of N addition on leaf dry matter content of Poaceae and Rosaceae, and only indirect effects on Fabaceae.

With the intensification of global climate change, inland river basins in arid desert regions are facing serious challenges in water supply and ecological and environmental protection. A water ecological security assessment is important as a key management tool in the context of inland river basins situated in arid desert areas. This study evaluated the water ecological security of the Hotan River Basin based on a combination of the Ecology–Produce–Life Space perspective and the Drive–Pressure–Status–Influence–Respond (DPSIR) model. The entropy value method and the composite index method were employed for this purpose, and a regression analysis was used to establish a prediction model to forecast the future water ecological security status. The results show that from 2013 to 2020, the water ecological security status of the Hotan River Basin exhibited a fluctuating upward trend, shifting from an average to a good status. The pressure layer has the greatest impact on water ecological security, while the ecological space within the Ecology–Produce–Life Space is increasing in the overall share year by year. In the future, the water ecological safety condition of the Hotan River Basin is expected to improve and remain in good condition. Taking the Hotan River Basin as an example, the results of this study, combining the Ecology–Produce–Life Space perspectives and the DPSIR model, provide in-depth theoretical and practical value for the evaluation and prediction of water ecological security in inland river basins in arid desert areas, provide a scientific basis and feasible suggestions for relevant decision-making, and emphasize the importance of ecological spatial protection and restoration for the sustainable development of human society and ecosystems.

Against global ecological and environmental challenges, water ecological security in arid desert regions is of great significance to regional ecological balance and socio-economic development. This study focuses on the Kashgar Prefecture, specifically the Yarkant River Basin and Kashigaer River Basin, in Xinjiang, China. Employing the perspective of the “Ecology-production-life Space” and the Drive-Pressure-Status-Influence-Respond (DPSIR) model, this study utilizes the objective entropy value method to construct a comprehensive evaluation index system to assess the status of water ecological security and its spatial security in the three regions from 2012 to 2019. The results show that the two major river basins and Kashgar Prefecture present an underbalanced state of production-led ecology, and life space lagging in the Ecology-production-life Space, with different trends and substantial fluctuations in the comprehensive indices of ecology, production, and life of the three. From the DPSIR model, the changes in the indices of the dimensions of the three are complicated, and the response indices are generally low. The composite indices of the two basins and the Kashgar Prefecture are in fair condition, which is affected by the synergistic influence of human activities and natural factors. The production pressure threatens the safety of water ecology, while the ecological protection has a certain degree of effectiveness, but still needs to be improved overall. The rate of improvement is slow due to the limitations of production-led and ecological lag in the future, although there is an upward trend. This study establishes a coupled, complementary assessment framework integrating spatial patterns and causal chains. It validates an evaluation model applicable to discontinuous multi-basin networks in an arid desert region, revealing the evolution patterns and core contradictions of water ecological security in arid multi-basin areas. The results of this study can provide a scientific basis and data support for the study of water ecological security in arid desert multi-basin watersheds.