Amidst drastic environmental changes, the intricate interplay and feedback mechanisms in the water–vegetation–atmosphere nexus experience alteration. Previous research primarily centres on the responses among variables within this system, with little known about whether and how these responses (sensitivities) change. Here, we employ the Evapotranspiration Stress Index (ESI) to represent the equilibrium of the nexus and develop a memory dynamic linear model based on Bayesian forward filtering. The model takes into account the carry-over effect in the “dry gets drier” self-amplify loop, allowing for a more effective estimation of the ESI time-varying sensitivity to associated influencing factors. Our analysis reveals that from 1950 to 2020, mainland China experienced a notable 4.74 % escalation in evapotranspiration stress. Surface soil moisture serves as a primary driver, whose sensitivity to ESI has surged by 9.49 % in the last decade compared to the early 2000s. Vapour pressure deficit (VPD) and leaf area index (LAI) also exerted a substantial role, with their sensitivities fluctuating approximately 22.91 % and −45.77 %, respectively. Moreover, the greening pace is linked to an increase in soil moisture sensitivity and a decrease in VPD sensitivity, suggesting that rapid greening may alter the ecological resilience against soil deficit and atmospheric drought. In comparison, the widely used moving window multiple linear regression (MLR) significantly overestimates sensitivity fluctuations, necessitating prudent interpretation of numerical estimates in related research findings. Our findings underscore the spatiotemporal variations in sensitivity, enriching the comprehension of ecosystem reactions to external factors, and offer essential insights for advancing greening endeavours.

Arid zone ecosystems, integral to terrestrial systems, exhibit relatively low stability and are prone to influences from human activities and climate change. To elucidate the influence on the ecological environment of the arid zone by climate change and human activities, the paper takes normalized difference vegetation index (NDVI) as an evaluation index of the ecosystem and uses trend analysis to evaluation of NDVI variation characteristics in the Shiyang River Basin (SRB) from 1990 to 2020. Simultaneously using methods such as partial correlation analysis and residual analysis to evaluate the impact of climate change and human activities on NDVI changes. This study yielded several key findings: (1) The NDVI in the SRB exhibits an increasing trend of 0.034/10a in the interannual variation. (2) The relation cooperatives between NDVI and the deviation of precipitation and temperature in the SRB range from −0.735 to 0.770 and −0.602 to 0.773, respectively. (3) The changes in land use and groundwater depth in the SRB have a certain impact on NDVI changes. (4) The proportion of areas with significant contributions (contribution rate greater than 60%) from climate change and human activities to NDVI change is 33.5% and 22.5%, respectively.

The sap flow and transpiration of three typical tree species (poplar, locust tree, and willow) in Ningxia are crucial for sustaining the ecosystem in the Ningxia Yellow River Irrigation area. However, there is a lack of clarity regarding the variations in sap flow and transpiration of these trees and their corresponding responses to environmental factors. From February to December 2021, this study selected 30 samples representing the three typical trees in the irrigation area and monitored their tree sapwood sap flow continuously and dynamically using the Thermal Diffusion Probe method. This study yielded several key findings: (1) Variations exist in sap flow density and transpiration among the three typical trees, with willows exhibiting higher sap flow density and transpiration than poplars and locust trees. (2) Tree transpiration showed a highly significant positive correlation with net radiation, temperature, and vapor pressure deficit, along with a highly significant negative correlation with relative humidity. (3) Soil moisture content undergoes changes under precipitation and artificial drip irrigation, but its correlation with tree transpiration is limited. (4) The primary environmental factors influencing poplars, locust trees, and willows are temperature, soil moisture content at a depth of 30 cm, and soil moisture content at a depth of 60 cm.

The research on the adaptive utilization of water resources (AUWR) is of great significance to improve the coordinated development among water resources, economic society, and ecological environment in complex environments, and to promote the development of adaptive utilization of regional water resources. Based on the calculation method of harmony theory and the calculation method of the comprehensive co-evolution model, this paper obtains the harmony degree and adaptive utilization capacity of water resources (AUCWR) of each subsystem in the Tarim River Basin (TRB), analyzes the main factors affecting the AUCWR, and finally compares the two methods. The results show that: (1) From 2004 to 2018, the AUCWR in the TRB has gradually improved (harmony theory method: from 0.43 in 2004 to 0.56 in 2018, with a growth rate of 30.23%; comprehensive co-evolution model method: from 0.37 in 2004 to 0.62 in 2018, with a significant increase of 67.57%) and (2) From the perspective of indicators, indicators such as per capita GDP, the proportion of non-agricultural output value in GDP, and per capita net income of rural residents have a greater impact on the AUCWR in the TRB. Using different calculation methods to analyze the temporal and spatial distribution characteristics of the AUCWR in the TRB has important guiding significance for the future development and utilization of water resources, economic and social development, and ecological environment protection.