Abstract Purpose - Environmental pollution and health issues are hot topics for discussion in modern society. However, there is a shortage of research on the influence of environmental pollution on health from the perspective of subjective factors such as environmental protection. Design/methodology/approach - Firstly, the 396 data were collected through a field study in Sichuan Province’s mountainous rural areas. hen, based on the KAP model, an interactive impact mechanism model on the health of rural residents was established. The relationship between background characteristics and environmental protection of rural residents was tested using chi square test and T-test. The impact mechanism of environmental protection awareness, attitude, behavior, and perception of environmental pollution on the health of rural residents was explored through a multiple linear regression model. Findings – The findings indicate that: (1) All core observation variables can be classified as strong or weak. Stronger environmental awareness is more likely to be found among younger village official with higher educational levels. (2) The health degree of rural residents is significantly affected by their attitude towards environmental protection in a positive way and by environmental protection behavior in a negative way. (3) Age, gender, marital status, and party member, have a significant impact on the health of rural residents. Originality - The study’s findings can serve as a scientific foundation for enhancing rural residents’ environmental protection and health degree.

Glacial lake outburst floods (GLOFs) are one of the most severe disasters in alpine regions, releasing a large amount of water and sediment that can cause fatalities and economic loss as well as substantial damage to downstream infrastructures. The risk of GLOFs in the Himalayas is exacerbated by glacier retreat caused by global warming. Critical economic corridors, such as the Rongxer Watershed, are threatened by GLOFs, but the lack of risk assessment specific to the watershed hinders hazard prevention. In this study, we propose a novel model to evaluate the risk of GLOF using a combination of remote sensing observations, GIS, and hydrological models and apply this model to the GLOF risk assessment in the Rongxer Watershed. The results show that (1) the area of glacial lakes in the Rongxer Watershed increased by 31.19% from 11.35 km2 in 1990 to 14.89 km2 in 2020, and (2) 18 lakes were identified as potentially dangerous glacial lakes (PDGLs) that need to be assessed for the GLOF risk, and two of them were categorized as very high risk (Niangzongmajue and Tsho Rolpa). The proposed model was robust in a GLOF risk evaluation by historical GLOFs in the Himalayas. The glacial lake data and GLOF risk assessment model of this study have the potential to be widely used in research on the relationships between glacial lakes and climate change, as well as in disaster mitigation of GLOFs.

The ongoing urban spatial transformation contributes to a more intricate and varied spatiotemporal correlation pattern between metropolitan expansion and the migrant population. In this study, the coupled coordination model (CCD) is applied to enable the quantification of the spatiotemporal correlation index of metropolitan expansion and migrant population from 2010 to 2020. Moreover, various correlation patterns are identified in this research, and the multiscale geographical weighted regression model (MGWR) is employed to examine the spatiotemporal heterogeneity of the influencing factors that contribute to this correlation. The research findings reveal the following insights: (1) The built-up areas increased twofold between 2010 and 2020, with an evident tendency toward southward expansion. In addition, population migration indicates slow migration in the inner metropolitan area and accelerated migration in the outer metropolitan area. The correlation between metropolitan expansion and migrant population follows a central–peripheral layer pattern that is characterized by a low-high-low progression. (2) While the balanced development of public services has somewhat decreased the differentiation patterns observed, the adjustments made to economic growth, employment, and residential markets have intensified the differentiation of spatiotemporal correlation characteristics between the metropolitan expansion and migrant population. (3) This study demonstrates that the Chengdu metropolitan area is transitioning from a rapid development stage driven by structuralism to a human-oriented new urbanization stage. This shift is evident through the clear stage pattern and central–peripheral layer features observed. Through the scientific planning of industry and public service layouts, the promotion of integration employment, residential markets, and the facilitation of urban–rural transformation can be achieved. Implementing these strategies can elevate the standard of human-oriented urban spatial governance, achieve coordinated and balanced development between built-up and residential spaces, and advance the high-quality, sustainable, and inclusive development of metropolitan areas.

Abstract Terrestrial biosphere models (TBMs) often adopt the Farquhar biochemical model coupled with the Ball-Berry stomatal conductance (\({g}_{s}\)) model to simulate ecosystem carbon and water fluxes. The parameters \(m\), representing the sensitivity of \({g}_{s}\) to the photosynthetic rate, and \({V}_{cmax}^{25}\), representing the leaf photosynthetic capacity, are two pivotal parameters but the two main sources of uncertainties in TBM simulations. The spatial and temporal variations of \(m\) in TBMs are still elusive, due to the lack of direct observations. It also remains unclear how accurate estimates of \(m\) and \({V}_{cmax}^{25}\) can improve the simulations of carbon and water fluxes. In this study, we used a Bayesian parameter optimization approach to infer seasonally varying \(m\) and \({V}_{cmax}^{25}\) from eddy covariance observations in a mixed forest stand at the Borden Forest Research Station located in southern Ontario, Canada, and used in-situ observations of \(m\) and \({V}_{cmax}^{25}\) for validation. Three strategies were tested for optimizing \(m\) and \({V}_{cmax}^{25}\), including the carbon, water, and carbon-water coupling scenarios. \(m\) and \({V}_{cmax}^{25}\) optimized from carbon-water coupling constraints shows best correlations with the measured \(m\) (R2 = 0.70) and \({V}_{cmax}^{25}\) (R2 = 0.70). By incorporating optimized \(m\) and \({V}_{cmax}^{25}\)with seasonal variations, we found considerable improvements in the estimated gross primary productivity (GPP) and evapotranspiration (ET) compared with constant \(m\) and \({V}_{cmax}^{25}\), with R2 increasing from 0.78 to 0.85 for GPP, from 0.65 to 0.71 for ET and RMSE reducing from 2.579 g C m− 2 d− 1 to 2.038 g C m− 2 d− 1 for GPP, from 1.151 mm d− 1 to 0.137 mm d− 1 for ET. This study proposes an effective approach to retrieve \(m\) and \({V}_{cmax}^{25}\) for TBMs and demonstrates the efficacy of incorporating seasonally variable \(m\) and \({V}_{cmax}^{25}\) for reducing the uncertainties in GPP and ET simulations, which supports accurate quantifications of land-atmosphere exchanges.

Soil erosion is the key factor leading to the degradation of tillage-layer quality, which directly threatens regional food and ecological security. To study the characteristics of soil structure, water retention capacity, and nutrient changes in the tillage layer of purple soil sloping farmland under different erosion conditions, a shovel soil erosion test was performed to distinguish the factors that hinder the tillage-layer quality of sloping farmland under different erosion degrees. The degradation of soil structure showed that with the intensification of erosion, soil bulk density, soil capillary porosity, and sand content displayed an overall increasing trend; the soil water retention degradation was expressed by the average increase in the soil water holding capacity and the average decrease in the infiltration rate; soil nutrient degradation was derived from the average decrease in soil nutrient content. At the initial stage of erosion, the soil nutrient degradation was extremely sensitive to soil erosion, which was the limiting factor of the tillage layer; when the erosion reached stage E-15 (erosion 15 cm), the soil nutrients, soil permeability, and soil capillary porosity became the limiting factors; for E-20 (erosion 20 cm), the limiting factors added an index on the basis of stage E-15, namely, soil total porosity. When soil erosion continued for 53 years, the tillage-layer quality index was lower than the threshold value (0.46). Reconstructing soil profile of the tillage layer is an effective way to break the limitations of the barrier factors and improve the tillage-layer quality.

To clearly realize the dynamic process as well as the dynamic fragmentation behavior of a long run-out rockslide, a novel numerical method for landslide simulation of the coupled finite-discrete element method (FDEM) was applied and the Jichang rockslide was used as a case. The calibrated simulation result of the FDEM in a rockslide deposit corresponds well with the real rockslide deposit. The main run-out process of the rockslide lasts for 75 s and can be divided into acceleration and deceleration stages, which last for 33 s and 42 s, respectively. The maximum overall rockslide movement speed is 35 m/s while the partial sliding mass reaches 45 m/s. The fracturing, fragmentation, and disintegration processes of the sliding mass can be clearly observed from the dynamic scenarios. Fracture energy generated by rock fracturing constantly increases with time in a non-linear form. Of the total fracture energy, 54% is released in the initial 5 s because of fracturing, and 39% of the total fracture energy is released because of fragmentation and disintegration in the last 35 s. The accumulated friction energy increases in the whole run-out process, and its magnitude is much greater than the kinetic energy and fracture energy of the sliding mass.

Ecosystem services (ESs) are the cornerstone of human well-being. On the Tibetan Plateau and in its subregions, understanding the effects of the spatiotemporal continuity in the trade-offs/synergies of ESs, and identifying their drivers, is crucial for ecosystem conservation and sustainable development. In this study, we investigated the spatiotemporal variation of four ESs (WY, water yield; SR, soil retention; HQ, habitat quality; CS, carbon sequestration) on the Tibetan Plateau, in 2000–2020. We introduced a new indicator (RESI, Index of the relationships between ESs) to measure the trade-offs/synergies among ESs and their magnitudes, and used GeoDetector to analyze the drivers of ESs and their relationships. The following results were obtained: (1) The four ESs exhibited similar geographical characteristics, being higher in the southeast and lower in the northwest. The spatiotemporal variation of WY and SR was similar to the precipitation trend. WY, SR and CS increased significantly (p < 0.05) in the region by 10.60%, 14.59% and 29.29%, respectively, while HQ remained stable across 79.41% of the area. (2) Most ES relationships on the Tibetan Plateau were found to be synergistic, except for WY_HQ, where trade-offs were observed, with trade-offs and synergistic areas accounting for 49% and 48%, respectively. (3) The climate was found to be a key driver of ESs and their relationships on the Tibetan Plateau. However, apart from climate, human activity was found to be dominant along the middle reaches of the Brahmaputra, while vegetation and topography dominated in Naqu on the Qiangtang Plateau and Southeast Tibet, respectively. This study uncovers disparities in the impacts of natural and human activity factors on ES relationships, providing valuable insights for decision-makers to maximize the benefits of ESs.

Agricultural drainage from catchment greatly impacts water quality in the hilly area due to high nitrogen concentrations in the central basin of Sichuan Province, China. The original ecological ditches have proven effective in removing associated nutrient loads, but their nitrogen removal efficiency is limited by the elevated nitrogen levels of overland flow and subsurface flow. Field experiments were conducted to optimize the drainage network to enhance the performance of ecological ditches and enhance nitrogen removal efficiency in hilly regions. The results suggested that ecologically permeable dam ditches exhibited superior total nitrogen (TN) and total phosphorus (TP) removal efficiencies compared to single dams, multiple dams, and ecological intercept dams. Specifically, in single, multiple, and ecological intercept dams, TN removal was 20.2 %, 12.7 %, and 2.5 % higher, respectively, while TP removal was 18.2 %, 10.3 %, and 3.7 % higher, respectively. The TN removal efficiency by the Hydrocotyle verticillate and Iris pseudacorus L. ditch was 15.8 % and 2.3 % higher than that of the Myriophyllum verticillatum L. and Hydrocotyle verticillata and Hydrocotyle verticillata and Thalia dealbata Fraser, respectively. The TP removal efficiency in Hydrocotyle verticillata and Thalia dealbata Fraser ditch was 11.4 % and 3.5 % higher than that in Myriophyllum verticillatum L. and Hydrocotyle verticillata and Hydrocotyle verticillate and Iris pseudacorus L., respectively. The soil bed ditch demonstrated superior TN and TP removal efficiencies, with rates of 15.2 % and 11.3 %, respectively, compared to the pebble bed and mudstone bed (2.9 % and 3.4 %, respectively). Therefore, the original ecological ditch was reinforced through a combination of fine-textured soil substrates, native emergent plants with large biomass and ecologically permeable dams to enhance the removal efficiencies of TN and TP in agricultural drainage. Following reinforcement and evaluation in 2020, the removal efficiencies of TN, TP, ammonia nitrogen (AN) and nitrate nitrogen (NN) in the strengthened ecological ditches increased to 58.1 %, 56.5 %, 56.8 % and 54.2 %, respectively. In this study, a scientific foundation for enhancing the efficacy of ecological ditches in mitigating nonpoint source pollution from agricultural drainage in mountainous and hilly regions of subtropical and developing countries is established.

Soil water is crucial for maintaining forest health by providing plants with a dependable water source. However, the understanding of the impact of soil moisture on plant water uptake, particularly in conditions of excess soil water, is limited. In this study, we investigated root water uptake strategies of dominant species along an elevational gradient in the subalpine region of the eastern Qinghai–Tibet Plateau. Our results demonstrated divergent relationships between soil moisture and water uptake fractions in the shallow soil layer, where moisture generally exceeds field capacity (θfc) during the growing season, and in the deep soil layer, showing negative and positive associations, respectively. This disparity is linked to soil water components: when plants mainly used shallow soil water, the relative proportion of plant–available water (the part of water between wilting coefficient and θfc) in the shallow soil was smaller compared to instances where plants mainly used deep soil water. Conversely, the pattern for gravity water was the opposite. This phenomenon is attributed to precipitation replenishing shallow soil with gravity water and deep soil with plant–available water, leading to poor aeration in the shallow soil and an abundance of plant–available water in the deep soil, and plants tended to shift to deep soil water as a result. Furthermore, the decrease in the relative proportion of plant–available water in the shallow soil along the elevational gradient results in plants in the lowest-altitude broadleaf forest obtaining more shallow soil water and less deep soil water, which can also enhance our understanding of how soil moisture components influence plant water–use strategies. Additionally, no hydrological niche segregation was observed among species in this humid environment. These results can improve our comprehension of soil–plant interactions in subalpine areas.