With the increasing global warming over the past three decades, the climatic zones and eco-geographical regions characteristics in China have changed. This study used the climatic data of 641 meteorological stations over the past three decades (1991-2020), as well as the high-precision data of eco-geographical elements to optimize the eco-geographical regions in China. The study updated the map of eco-geographical regionalization in China (2023) and increased the scale to 1:4000000. The new map divided China into 11 temperature zones, 22 dry and wet regions, and 50 natural regions. The results show that compared with eco-geographical regionalization in 2007, the overall pattern of eco-geographical regions in China has not changed significantly over the past three decades, but the boundaries of temperature zones, dry and wet regions, and eco-geographical regions (natural regions) in some areas have changed to some extent. Firstly, the boundary change of temperature zones is more obvious in the east. Particularly, in the middle and lower reaches of the Yangtze River, the northward shift of the temperature zone boundary between the northern subtropical and the mid-subtropical zones is obvious. Secondly, the boundary between dry and wet regions has changed, and that between semi-arid and arid regions in the north of the second-order landform step has shifted slightly to the west. In addition, the boundary between semi-arid and sub-humid regions in the Qinghai-Tibet Plateau has shifted slightly to the southeast, reflecting a slight expansion of the scope of semi-arid regions. Finally, boundary changes in natural regions in some areas vary greatly. This study can provide a macro-regional framework for guiding ecological conservation and restoration in different regions.

Indoor combustion of low-quality coal chunks significantly contributes to wintertime haze episodes and directly affects indoor air quality, posing high risks to human health. Besides electricity or gaseous fuels, clean coals and pelletized biofuels have been proposed as alternative fuels to reduce pollutant emissions associated with raw coal burning in some policies and pilot projects. However, there is still a lack of quantitative evaluation on real-world indoor air quality from homes using different heating fuels. This limits a comprehensive understanding of the environmental and health co-benefits of clean heating policy. In this study, indoor fine particulate matter (PM_2.5) was measured from 1600 households located in rural north China. The aim was to assess indoor PM_2.5 variations within and between different homes and attribute the pollution differences to heating types. The study found that the average indoor PM_2.5 during the heating period was 102 μg/m³, but it varied greatly from 19 to 497 μg/m³. In the home burning traditional coals and biomass fuels, the indoor PM_2.5 concentrations were as high as 162 μg/m³ and 144 μg/m³, respectively, while in the home using clean coals or biomass pellets, the indoor PM_2.5 levels were significantly lower, at about 84 μg/m³, although this still exceeded the national standard (50 μg/m³) during more than 56% of the entire monitoring period. The lowest indoor PM_2.5 levels were observed in the home using clean modern energies like electricity or gas for heating. Due to distinct human activity intensities and meteorological conditions, the indoor PM_2.5 also varied greatly from day to day. The coefficient of variation (COV) in indoor PM_2.5 from different days was approximately 76% in the home using solid fuels, while it averaged 53% in the home using clean energies. Internal combustion sources contributed to about 60% of indoor PM_2.5 in the home burning traditional solid fuels. When switching to cleaner household energies, internal combustion emission contributions declined obviously. To lower indoor PM_2.5 levels, low-quality dirty coals should be suspended and replaced by cleaner energies like pelletized biofuels or clean coals, and the most significant reduction would be achieved by switching from coals to electricity. The present study provides empirical evidence from first-hand observational data to enhance the understanding of indoor air pollution variability. It supports a comprehensive scientific evaluation of clean heating policy in terms of air pollution mitigation and human health protection.

The utilization of surplus straw and manure derived from the crop and livestock production systems for bioenergy production presents a valuable approach to mitigate environmental pressures associated with the crop-livestock system, while concurrently addressing greenhouse gas emissions. This study establishes an integrated framework encompassing crops, livestock and bioenergy, and employs a life cycle assessment methodology to quantify the greenhouse gas emissions inventory across diverse processes within crop and livestock production systems at both national and provincial scales from 2010 to 2019. By comparing emissions and regional differentials between the integrated crop-livestock-bioenergy system and conventional system during distinct production phases. These findings shed light on the environmental impact of the integrated approach on agricultural emissions. The findings reveal that: (1) Notably, the baseline scenario identifies three key sources of agricultural greenhouse gas emissions: crop straw management, livestock enteric fermentation, and energy consumption in crop production, with notable regional variations. (2) Environmental impact intensity shows a fluctuating trend in most regions or provinces, with a pronounced decline (-0.73×10^-2) observed in eastern China, while Xinjiang experiences the largest increase (0.63×10^-2). (3) The abundant surplus straw and manure in these systems present a significant opportunity. The integrated system demonstrates a remarkable ability to mitigate agricultural greenhouse gas emissions, potentially cutting nationwide environmental impacts by up to 67% at its maximum.

Water eco-environment monitoring is the premise and foundation of habitat protection. In view of the characteristics of the Yangtze River Basin's water system, which is diverse, complex, and ever-changing, higher requirements are put forward for monitoring methods. At present, the water quality monitoring methods for large surface water systems are still mainly based on manual sampling combined with laboratory chemical analysis or on-site hand-held instrumental analysis. There are problems such as method lag, single means, low frequency, and lack of non-point sources. Therefore, there is an urgent need for new system monitoring technology, which breaks through real-time, fast, non-point source quantitative and other practical needs, and provides a reliable data source for the comprehensive simulation of the Yangtze River water system. In this context, this paper proposes a fine spectral detection and quantitative analysis technology with completely independent intellectual property rights, and develops ground-based, space-based and other system technologies and equipment. With the support of the relevant projects, the demonstration application of systematic technology was carried out, and the space-ground stereoscopic monitoring was conducted in the key sections of the main stream of the Yangtze River, the Three Gorges Demonstration Area and the Poyang Lake Demonstration Area, and good results were achieved. The monitoring data are connected to the "Yangtze River Simulator" through the cloud platform, which provides fast real-time data support for its comprehensive operation, as well as a new method and application model for the comprehensive monitoring of large-scale water systems in the future.

The construction of China's ecological civilization, known as "Beautiful China", necessitates implementing precision watershed management through scientifically informed decision-making. This entails optimizing the spatial distribution of watershed best management practices (the so-called BMP scenario) and proposing multistage implementation plans, or roadmaps that align with practical requirements based on the overarching vision of comprehensive watershed management. The "watershed system simulation-scenario optimization" method framework (the simulation-and-optimization-based framework for short) has demonstrated considerable potential in recent years. To address challenges arising from practical applications of this framework, this study systematically conducted the methodological research: (1) proposing a novel watershed process modeling framework that strikes a balance between modeling flexibility and high-performance computing to model and simulate watershed systems efficiently; (2) introducing slope position units as BMP configuration units and enabling dynamic boundary adjustments during scenario optimization, effectively incorporating practical knowledge of watershed management to ensure reasonable outcomes; (3) presenting an optimization method for determining the implementation orders of BMPs that considers stepwise investment constraints, thereby recommending feasible roadmaps that meet practical needs; and (4) designing a user-friendly participatory watershed planning system to facilitate collaborative decision-making among stakeholders. The effectiveness and practical value of these new methods, tools, and prototype systems are validated through application cases in a representative small watershed. This research contributes to advancing precision watershed management and provides valuable insights for sustainable ecological conservation. The methods proposed within the simulation-and-optimization-based framework in this study are universal methods, which means their application does not depend on the specific implementation, such as the watershed process model, the BMP types considered, the designed BMP configuration strategy, and so on. Further studies should be conducted not only to deepen related theory and method research but also to strengthen promotion and application, especially cooperating with local watershed management agents to provide valuable insights for their sustainable ecological conservation.

Coastal wetlands, a pivotal realm of sea-land interactions, exhibit profound ecological sensitivity. Increasingly shifting climatic patterns and intensifying anthropogenic interventions pose formidable challenges to the sustainable utilization of these invaluable assets. Cultural ecosystem services (CESs) represent a subtle, yet crucial conduit connecting the natural environment and human society, thereby playing a pivotal role in the holistic management of coastal and oceanic domains. This study employed the theoretical framework of CESs involvement in the sustainable management of coastal wetland resources, and integrated multi-sourced social media data with the MaxEnt model to conduct an empirical investigation focused on nine Chinese coastal wetlands which are listed in Ramsar Convention. The results reveal the following: (1) From the mean level of each CES, the coastal wetlands with the strongest capacity for biodiversity, historical, educational, and recreational service respectively was the Guangxi Shankou Mangrove Wetland (0.222), with a high level area of 61.218 km², accounting for 27%; Fujian Zhangjiangkou Mangrove Wetland (0.336), with a high level of 9.037 km², accounting for 17%; Tianjin Beidagang Wetland (0.092), with a high level of 70.981 km², accounting for 11%; and Fujian Zhangjiangkou Mangrove Wetland (0.350), with a high level of 9.037 km², accounting for 17%. (2) Delineating the spatial differentiation pattern of each CES, the high-level zone for biodiversity service in Shankou Mangrove Wetland is predominantly clustered within the eastern and central regions. A high level of historical service was more significant in the western and eastern Fujian Zhangjiangkou Mangrove Wetland. Regarding educational service in the Tianjin Beidagang Wetland, high-level areas were clustered in the western sector. The high-level recreational service areas of the Zhangjiangkou Mangrove Wetland were mainly clustered in estuarine area. (3) Assessing the contributions of environmental variables to CESs, it became evident that distance to nature reserves, land-use type, and distance to bird habitats emerged as the principal factors steering the divergences in biodiversity service patterns. Simultaneously, distance to infrastructure, roads, and bird habitat proximity significantly influenced the historical, educational, and recreational services within the nine coastal wetlands, albeit to varying extents. (4) In line with both regional and national strategies, this study categorised sustainable resource management approaches for the nine coastal wetlands into three distinct modes: ecological restoration, ecological and cultural rejuvenation, and ecological and industrial integration, thereby presenting innovative paradigms for the research and implementation of comprehensive governance within China's coastal and oceanic domains.

Ecological restoration measures have a significant impact on biodiversity hotspots. Therefore, quantifying the contribution of desertification control to biodiversity is crucial in the karst region of southwest China. This study employed regression analysis and residual trend analysis to reveal the evolutionary patterns of desertification and biodiversity from 2000 to 2020 in this region. It quantified the contributions of desertification control and other factors to biodiversity. The results indicated that during the study period, desertification in the karst region was mainly classified as mild and moderate levels, with a total area reduction of 102500 km² at an annual rate of 4900 km²/a. Overall, biodiversity showed an increasing trend, with a mean value of the biodiversity composite index at 0.40, maintaining a moderate level. There was a positive correlation between desertification control and biodiversity, with desertification control contributing 26.39% of the overall impact. Climate change and human activities contributed 52.78% and 47.22% to biodiversity, respectively. This suggests that desertification control has made a positive contribution to biodiversity and provides valuable guidance for future ecological restoration projects and biodiversity conservation.

As one of the long-term solutions to the global climate change problem, the harmonious dynamic relationship between supply and demand of blue carbon is of great significance in promoting regional carbon balance and sustainable management. With the rapid socio-economic development, the landscape fragmentation of the coastal zone is significant, which directly affects the ecological processes such as energy flow and material circulation in its system. However, the effects of coastal zone landscape fragmentation on the supply-demand relationship and flow of carbon sequestration services are not clear. Based on the framework of the impact of coastal landscape fragmentation on carbon sequestration service flow, this study synthesizes land use data, carbon storage sampling data and nighttime light data, and employs the moving window method, the InVEST model and the network model to conduct an empirical study in the Liaohe River Delta, a typical silty coastal zone in northern China. The results show that: (1) From 1995 to 2020, with the intensification of landscape fragmentation in the Liaohe River Delta, the demand for carbon sequestration services increased by 30.44 million tons and the supply of carbon sequestration services increased and then decreased, with the overall change being insignificant, and the difference between the supply and demand of carbon sequestration services increased from 4.49 million tons in 1995 to 33.76 million tons in 2020. (2) The negative impact of landscape fragmentation on the carbon sequestration service flow varied among different anthropogenic intensity, with more pronounced impact on agricultural reclamation areas, increasing and then decreasing impact on industrial port reclamation areas, while little impact on reed wetlands. (3) The impact of landscape fragmentation on the spatial pattern of carbon sequestration service flow is reflected in the density and connectivity of carbon sequestration service flow network, interrupting service flow and changing the direction of service flow. (4) The reed protection areas and agricultural reclamation areas have important ecological functions, and ecological red line should be strictly controlled to enhance carbon sequestration capacity. The industrial port reclamation areas should strengthen the construction of ecological corridors to enhance landscape connectivity and restore carbon sink function. This study reveals the relationship between landscape fragmentation and carbon sequestration service flow, and the results can provide scientific basis and management reference for ecological restoration and carbon sequestration capacity enhancement in China's conservation strategic key areas and other similar silt coastal zones around the world.