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.