As urbanization and industrialization advance, China faces increasingly severe ecological challenges. The Ecological Protection Redline (EPR) policy is a crucial tool for land use management and ecological protection but requires a comprehensive risk assessment method to address ongoing challenges. This study integrated multiple factors with ecological resilience theory to establish a Hazard-Exposure-Vulnerability-Damage-Final Risk framework, assessing the spatiotemporal dynamics and risks of different EPR types in Qinghai Province over 20 years. Path analysis was further used to reveal relationships between risk stages. Results show increasing hazards and exposure in Water Conservation (WC), Biodiversity Maintenance (BM) and Land Desertification (LD) EPR types, with improved water conservation, stable biodiversity, and controlled desertification vulnerability across regions. Integrated risk results show a downward risk trend in WC type, BM type fluctuated but improved, and an initial increase followed by risk decrease in LD type. Path analysis revealed that damage in WC-type EPR was driven by direct hazard impacts, BM-type EPR by vulnerability, and damage in LD-type EPR by indirect effects of hazard through exposure. This study emphasizes the optimization of EPR policies by reducing external disturbances and enhancing ecosystem resilience, providing policy recommendations and practical experience for ecological protection and sustainable land use management.

Shallow slope failures occur frequently in the Loess Plateau region and the ecological materials are usually used for slope protection. The mechanical characteristics and strength models of the interface between environmental protection materials and native materials are crucial for evaluating the effectiveness of slope protection. In this study, the polypropylene fiber and guar gum are used for slope protection, and indoor experiments are conducted to elucidate the mechanical performance changes at the interface between untreated loess (UL) and guar gum-treated fiber-reinforcement loess (GFL) under different moisture content and curing time. A damage strength model of the interface between untreated loess and guar gum-treated fiber-reinforcement loess (UL-GFL) is constructed based on statistical damage theory. The results show that guar gum can aggregate and cement loess particles, while polypropylene fiber enhances the friction between loess particle aggregates. The synergistic effect of these two materials significantly improves the strength and hydraulic characteristics of loess. The cohesion and internal friction angle of the interface between untreated loess and guar gum-treated fiber-reinforcement loess decrease with an increase in moisture content and increase with an extended curing time, stabilizing when the curing time exceeds 7 days. The strength model for the interface of untreated loess and guar gum-treated fiber-reinforcement loess is established. The proposed model is verified through experimental data based on the stress-displacement relationship. The findings of this research can provide an important reference for the application of ecological protection materials on loess slopes.

External-soil spray seeding technology is a widely used method for ecological slope protection, playing a significant role in mitigating soil erosion, landslides, and other geological challenges. However, research on the technical stability of external-soil spray seeding is limited, resulting in suboptimal protective effects and hindering broader application. This review highlights emerging research themes for advancing ecological slope stability, including: ecological substrate, vegetated ecosystem, the mechanical properties and hydrological characteristics of the external-soil spray seeding technology. The review identifies new research themes for developing futuristic ecological slopes can be summarized as: (1) whether or not to find the stability models on the shear strength and bond strength of the substrate under water saturation, (2) how to establish models with the effect of grassland ratio, slope angle, seeding amount, and planting season on the long-term growth of ecological slope protection, (3) how to improve quantitative mechanical models between the roots and soil, (4) how to propose the relevant analytical and numerical methods for root-soil-atmosphere. The findings offer valuable guidelines for improving ecological slope stability and advancing the application of external-soil spray seeding technology.

The construction of fill slopes becomes a critical aspect when there is a need to change the terrain or create new terrain. However, due to the poor engineering properties of the fill material, especially when red sandstone with notable disintegration properties is used, the risk of slippage or collapse may occur. This material is prone to erosion and disintegration under the action of natural factors such as heavy rainfall, leading to severe soil erosion and slope instability. In addition, the construction of fill slopes inevitably causes the destruction of native vegetation, exacerbating environmental problems. To address these problems, an novel ecological approach for preventing water damage to red sandstone fill slopes was developed using the vegetation-high-performance turf reinforcement mat -anchor-drainage pipe-synergistic slope protection system. Three test red sandstone slopes with different protection methods (unprotected, three-dimensional (3D) protection mesh, and vegetation ecological protection system slopes) were constructed, and the feasibility and reliability of ecological protection against water damage to red sandstone fill slopes were analysed via the field test method. The results showed that the vegetation ecological protection system can effectively inhibit soil erosion and increase the survival rate of vegetation roots. Moreover, the the high-performance turf reinforcement mat provides a strong protective complex through interactions with vegetation roots, anchors, and drains, which significantly enhances slope stability. Under heavy rainfall conditions, the vegetation ecological protection system can effectively limit slope erosion due to water scour, thus maintaining the structural integrity of the slope.

Soil water content (SWC) and soil temperature (ST) are important indicators of environmental change in permafrost regions. In this study, we conducted soil sampling at 89 locations in the Three Rivers Headwaters Region (TRHR) to investigate the individual and synergistic effects of environmental factors on SWC and ST. We used multivariable regression and random forest modelling to analyse the data. The results show that SWC and ST were higher in the southeast TRHR than in the northwest and higher in surface layers than deeper soil layers. The most important factors affecting SWC in the 0-20 cm and 20-40 cm soil layers were soil bulk density and precipitation, while bulk density was the most important factor in the 40-60 cm layer, and soil bulk density and steppe vegetation were the most important factors in the 60-80 cm layer. For ST, altitude, temperature and slope gradient were the drivers in the 0-20 cm surface layer, while altitude and temperature were the most critical drivers in the 20-40 cm, 40-60 cm and 60-80 cm layers. Overall, bulk density and altitude were the key environmental factors influencing SWC and ST values, respectively. The outcomes of this study provide valuable insights into the environmental factors that impact the SWC and ST in permafrost regions, which can guide decision-making processes for sustainable soil management in the context of climate change.

Research on mountain ecosystem services (MES) under the influence of climate change and human activities has gradually become the focus of academic attention in recent years. Here, this study analyzes the research hotspots and frontiers of this field based on metrics including main research forces, core journals and papers, research hotspots and topics by using the methods of bibliometrics and text mining. The results revealed the following: (1) the number of papers is increasing rapidly in recent years. From 2015 to 2019, 929 papers were published, with an average of 185 papers per year. But the average cited times of those papers is declining, dropped from 6.01 in 2016 to 4.2 in 2019. The USA, UK, and China rank the top three of the number of papers. Univ Maryland, Univ Oxford and Univ Wisconsin have the greatest influence, with an average of more than 77 citations per paper; (2) The most cited journals are PNAS, WETLANDS, ECOLOGY, AND SOCIETY, which are cited 191.54, 53.91, and 40.00 respectively. Most papers were published in OA journals including SUSTAINABILITY, WATER, Forests since 2017. Ten core papers undertaking knowledge transfer in this field have been identified; (3) analysis of the keywords found a new trend of integration of natural science and humanities. In two development stages of 2000-2014 and 2015-2019, the research hotspots mainly focused on mountain water resources, forest resources, land resources and the impact of climate change and human activities, and there are obvious differences and characteristics in different stages. The hotspot worthy of attention in the near future is the assessment of mountain ecosystem services capacity and value. This is the first comprehensive visualization and analysis of the research hotspots and trends of mountain ecosystem services.