Urban renewal has become a frontier topic in urban development and transformation. The rent gap theory, by revealing the phenomenon of capital flowing back into inner-city areas, has become one of the classic theories explaining the internal mechanism of urban renewal. This study explored the evolving characteristics of the rent gap concept through an in-depth review and systematic summary of typical literature and reviewed the development trends of urban renewal both in China and internationally. On this basis, it further elaborated on the progress of applying the rent gap theory in urban renewal. The introduction of the rent gap concept reveals the intrinsic mechanism and driving force behind capital investment in the urban built environment. Over time, the connotation of the rent gap has been continuously enriched and expanded, exhibiting features such as inclusivity, humanism, global-oriented, diversity, and innovation. This also reflects the gradual transformation of urban renewal towards aspects like business revitalization, ecological restoration, scene creation, cultural heritage, and innovation-driven development, highlighting key characteristics such as gradual orderliness, multi-stakeholder governance, and policy orientation. The development of rent gap theory showed four significant evolutionary characteristics: the increasingly comprehensive development of the theory's connotation; the shift from spatial incremental rent to including non-spatial incremental rent; the diversification of rent gap measurement models; and the shift in focus from capital logic to fairness in benefit distribution. Urban renewal in China and internationally presents development models oriented towards real estate, culture, and technological innovation. The integration of rent gap theory with urban renewal practices is deepening, and this study attempted to propose innovative ideas from the perspective of the rent gap theory to address the conflicts in China's frontier urban renewal. The aim was to provide a theoretical reference for China's urban development and transformation, contributing to the high-quality development and the construction of Chinese-style modernization.

As a unique geomorphic configuration of small watersheds on the Loess Plateau, the land use pattern change in the slope-gully system profoundly affects the process of human-environment interactions. As a critical area of human-environment interactions on the Loess Plateau, the loess hilly-gully region has undergone substantial and obvious changes in its landuse patterns. Based on a literature review and inductive summary, this study first established the theoretical understanding of the slope-gully system. Then, it systematically summarized the spatiotemporal change, resource-environmental effects, and optimization pathways of land use patterns across diverse landforms in the loess hilly-gully region since 1980. Finally, we proposed the future direction for the in-depth study of land use patterns in the slope-gully system. The results show that: 1) Due to significant spatial heterogeneity of both natural and socioeconomic factors across different sections of the slope-gully system, land use patterns exhibit clear horizontal and vertical differentiation. 2) Currentstudies primarily focus on natural aspects such as soil erosion, water-sediment processes, and vegetation dynamics, while limited attention has been paid to socioeconomic effects, including farmers' livelihoods and non-agricultural employment opportunities. 3) The optimization paths of land use patterns in the slope-gully system can be categorized as problem-oriented, resource-utilization-based, and systematic design paths. However,the optimization paths mostly concentrate on local engineering or single planting structure adjustment, lacking integrated design frameworks and comprehensive socioeconomic evaluations. Moving forward, it is essential to develop a theoretical framework for land use pattern research in the slope-gully system grounded in the coupling theory of human-environment systems. Advanced technologies, such as high-resolution remote sensing and 3D real-world mapping, should be used to accurately quantify vertical land use pattern changes and to carry out the diagnosis of problems and optimization of layout design of multi-scale land use patterns of the slope-gully system. Last, future study can engage with cutting-edge international studies on land-use patterns in slope-gully systems, especially extending from regional analyses to global perspectives. This study provides theoretical insights and technical pathways to deepen the understanding of land use pattern changes in the slope-gully system, contributing to the optimized allocation and sustainable management of land resources in the loess hilly-gully areas.

Visceral geography, proposed by Jessica Hayes-Conroy and Allison Hayes-Conroy in 2010, is a theoretical paradigm that emphasizes how internal bodily sensations participate in spatial practices at non-rational and non-verbal levels. This article interprets visceral geography as the socially construted visceral bodily experience, in order to distinguish it from biologically innate bodily responses. Although Western scholars have extensively explored this framework across topics such as food, emotion, gender, and race, existing research often suffers from weak theoretical integration and fragmented analytical frameworks. In response, this article systematically reviewed the theoretical development of visceral geography, clarified its central proposition of "bio-social dual encoding", and proposed an analytical framework consisting of embodiment, relationality, and transformative potential to deepen understanding of this paradigm. It further identified three major research themes: the visceral politics of food, racialized spatial politics, and embodied politics of place, demonstrating how bodily experience actively engages with spatial power relations. Finally, the article offered a theoretical reflection from the perspective of the Chinese context and engaged in a dialogue between Chinese and Western scholarships, highlighting the potential applications of visceral geography in research in China. By introducing visceral geography into the Chinese geographical discourse, this study explored how bodily experience is embedded in spatial political practice and thus contributes to expanding the theoretical horizon of body geography.

Tourism geography is a discipline that studies the spatial differentiation patterns, temporal development processes, and regional characteristics of tourism phenomena, tourism elements, and comprehensive tourism geographic systems. In the new development stage, grounding itself in China's context, addressing theoretical, practical, and methodological issues in China's tourism development practices, and providing Chinese paradigms and solutions for knowledge production are not only the mission of the Chinese tourism geography discipline but also key to enhancing its own disciplinary vitality. The disciplinary vitality of Chinese tourism geography is rooted in the scale, uniqueness, and complexity of China's tourism development practices, and is manifested in the process where tourism, as an "emerging developmental element and driving force", actively responds to national strategies and socioeconomic development needs. This study systematically reviewed the development processes and trends of knowledge production in tourism geography from the perspectives of disciplinary systems, academic systems, and discourse systems. The findings indicate that: 1) Multiple environmental factors, including institutional, socioeconomic, cultural, and disciplinary development contexts, collectively shaped the substantive content, presentation methods, and the theoretical and methodological consciousness of knowledge producers in tourism geography in China. 2) The construction of an autonomous knowledge system in Chinese tourism geography faces both internal and external challenges. External challenges are reflected in the mismatch between the construction of an international discourse system and China's international status, the disparity between developmental advantages and thematic advantages, and practices of academic hegemony. Internal challenges include the marginalization of tourism geography within the disciplinary system, fragmentation of research outputs, and the lag of theory behind practice. 3) Examining tourism development practices of Chinese-style modernization with a problem-oriented disciplinary awareness, defining the essential orientation of knowledge production in Chinese tourism geography with an academic innovation consciousness, and strengthening the autonomous narrative system of Chinese tourism geography with a discourse dialogue awareness are beneficial directions for overcoming the autonomy challenges. Accelerating the construction of an autonomous knowledge system in Chinese tourism geography is fundamental for enhancing the disciplinary vitality of tourism geography.

Faced with global biodiversity loss and degradation of ecosystems, rewilding, a new concept, method, and application in the field of ecological protection and restoration, aims to restore the structure and function of native ecosystems through reducing human intervention, and has become a focal topic in promoting the paradigm shift between humans and nature and ecological governance. This paper systematically reviews the development trajectory and research progress of rewilding, summarizes the achievements made in the current stage, and proposes future prospects for expanding and deepening rewilding. The research findings indicate that: (1) The theoretical guidance of rewilding in practice needs to be strengthened. While the range of involved disciplines continues to expand, there remains a lack of unified concepts, clear connotations, and a solid theoretical foundation. (2) The method of identifying and evaluating relies on the building of an index system; however, the research remains confined to macro- and meso-scales and largely static, single-time-point studies. It has yet to reveal fine-grained, micro-scale dynamics or their continuous long-term evolutionary trends. (3) The analysis of influencing factors and the underlying mechanism of rewilding remains underdeveloped. Existing studies predominantly concentrate on identifying specific causes in typical cases, while often overlooking the influence of social and institutional backgrounds. (4) The research on the effects of rewilding is mainly focused on qualitative descriptions of the impact on biodiversity and the ecosystem itself, and the comprehensive regional effects assessment and quantitative method construction for achieving sustainable development goals need to be expanded. (5) The optimization of governance for rewilding needs to pay more attention to the behavior of stakeholders, and the study of the application of rewilding in a complex system that takes into account the process of harmony between man and nature needs to be deepened. Based on the research results, the paper builds an integrated framework of “theoretical analysis➝process analysis➝mechanism analysis➝effect analysis➝optimized governance”, identifies key research directions for future emphasis, and aims to provide new insights and pathways for improving China's ecological protection system and advancing harmony between humans and nature.

Gully erosion is a typical geomorphic evolution process on the Loess Plateau as well as in other loess regions of the world. However, the analysis of erosion process has been hindered due to the limitations of existing research methodologies. In this article, we reviewed and compared three research methods for gully erosion on the Loess Plateau, both in China and internationally, based on their characteristics in terms of spatiotemporal resolution. Among the gully erosion research methods, geomorphological analysis, which is based on the principles of geology and geomorphology, can explain the relative age of the gully erosion process in the region during the geologic period, but cannot determine the absolute age of gully erosion. The dating and documentary research methods, which are based on the multi-dating technology and historical documentary analysis, can accurately reflect the evolution process of gully erosion around the dating site by using absolute chronological dating. However, these methods are applied on a small spatial scale and are unable to analyze the temporal continuity of gully erosion. Model simulation methods include empirical statistical models, physical process models, and complex system models, which rebuild the historical erosion process at high spatiotemporal resolution based on multi-source data and interdisciplinary technologies. However, there are few research achievements based on these methods. The three types of methods each has its own strengths and focuses on different aspects of gully erosion, showing the characteristics of critique-integration-transcendence. In general, the results of the existing research methods are more microscopic than macroscopic in spatial scale, more static than dynamic at the temporal level, and more independent than coupled technically. With the development of data acquisition, interdisciplinary exchange, AI technology, and multimodal large language models, their data processing and coupling analysis capabilities will be greatly enhanced, which can overcome the spatial scale limitations, improve the accuracy of time series analyses, and increase the coupling of analyses and methods, ultimately providing a future solution to the shortcomings of existing gully erosion research methods.

Dietary ecology is fundamental to understanding wildlife-habitat interactions, serving as a cornerstone for assessing environmental carrying capacity, habitat quality, habitat selection behavior, trophic structure, and interspecific competition/mutualism in community ecology. It remains a pivotal focus in endangered species conservation and biodiversity management. Ornithologists have long recognized the significance of dietary studies; for waterbirds-key indicator taxa in wetland ecosystems-dietary data elucidate species-environment energy/material linkages and critically inform ex situ conservation strategies and captive breeding optimization, particularly for threatened species. Methodologically, waterbird dietary research employs diverse approaches. Traditional techniques (direct observation, gizzard/crop content analysis, fecal microscopy) historically dominated the field. Technological advances now highlight DNA metabarcoding for its high taxonomic resolution, though constrained by sample DNA degradation and cost-intensive procedures. Conversely, stable isotope analysis demonstrates broader utility: beyond resolving dietary composition, it enables migration tracking, quantification of seasonal dietary dynamics, trophic-level mapping, and evidence-based population management and wetland restoration. Amid accelerating climate change and pervasive habitat loss/fragmentation, the scope of waterbird dietary research now transcends conventional boundaries. Objectives have expanded from basic diet characterization to multidimensional investigations of spatiotemporal foraging patterns, habitat restoration efficacy, and migratory ecology. Methodologically, interdisciplinary integration (ecology, genetics, physiology, molecular biology) drives advances in: climate-driven dietary adaptation mechanisms, gut microbiota-diet interactions, paleo-dietary evolution from fossil evidence, migration-resource phenology alignment, precision wetland rehabilitation. High-throughput, information-rich analytical tools (e.g., DNA metabarcoding, stable isotopes) provide unprecedented resolution for quantifying dietary seasonality, migration-stage shifts, and species-distribution-environment relationships. With persistent technological advancements and scientific inquiry, waterbird dietary ecology will increasingly underpin biodiversity conservation, ecosystem governance, and global change mitigation.

Turbidity, as a key optical parameter measuring the scattering and absorption of light by suspended substances (including organic/inorganic particles, phytoplankton, and microorganisms), is one of the core indicators in water quality assessment. In recent years, frequent pollution events in inland water bodies, such as tailings leakage, abnormal turbidity discharges from reservoirs, and industrial runoff, have heightened the need for efficient and accurate water quality monitoring technologies. Traditional turbidity monitoring methods rely on field sampling and laboratory analysis. Although these techniques provide high-accuracy results, they are inherently limited in spatial coverage and temporal frequency, while also being labor-intensive and time-consuming. With the advancement of remote sensing technology, the acquisition of multispectral data via satellite or aerial platforms has emerged as a promising and cost-effective approach for large-scale and periodic turbidity retrieval. Remote sensing-based turbidity estimation offers several advantages, including wide-area coverage, temporal consistency, and the ability to monitor inaccessible regions. A bibliometric analysis of 574 relevant research articles indexed in the Web of Science reveals a clear upward trend in the number of turbidity-related remote sensing studies. Moreover, the diversity of satellite data sources continues to expand. Among them, the Landsat series stands out as the most commonly used due to its 30 m spatial resolution and extensive historical archive spanning over four decades. Other widely adopted sensors include MODIS (Moderate Resolution Imaging Spectroradiometer), which is suited for large-scale observations; MERIS (Medium Resolution Imaging Spectrometer), known for its ocean color-specific spectral bands; and Sentinel-2 MSI and Sentinel-3 OLCI, which strike a balance between spatial and spectral resolution. In terms of retrieval methodologies, early studies primarily employed linear or polynomial regression models. Over time, more sophisticated approaches have emerged, forming a diverse methodological framework. These include empirical models such as single-band threshold methods and band ratio algorithms, semi-analytical models that incorporate water optical properties, and data-driven machine learning algorithms that offer improved flexibility and adaptability. However, accurately estimating turbidity in optically complex inland waters remains a challenge, primarily due to the heterogeneous absorption and scattering effects of different water constituents. Looking forward, future research should prioritize three key directions: integrating multi-source remote sensing data to overcome limitations in spatial and temporal resolution; improving atmospheric correction algorithms to effectively eliminate interference from aerosols and atmospheric particles; and developing classification-based retrieval frameworks that account for the variability of water optical properties across different inland water types. These efforts will collectively enhance the accuracy, robustness, and general applicability of turbidity remote sensing in complex inland aquatic environments.

As an important water source for human activities and economic development, the protection of lake water quality is crucial, and the mechanisms by which different types of agricultural activities affect lake water quality is urgently needed further in-depth study. With the continuous expansion of agricultural reclamation activities, processes such as farmland fertilization, pesticide use, and changes in land cover have significantly altered the patterns of material input and energy transfer in lakes, necessitating an in-depth study of their quantitative relationship with lake water quality parameters. Although existing studies have focused on the impact of agricultural activities on lake water quality, the mechanisms by which different types of cultivation, spatial patterns, and climatic conditions affect lake optical water quality parameters are still not well understood. Lake optical water quality parameters (such as chlorophyll-a (Chl-a), total suspended particulate matter (TSM), and colored dissolved organic matter (CDOM)) not only reflect the nutrient status and biological productivity of the water body, but also serve as important inputs and validation indicators for remote sensing-based water quality models. Based on recent domestic and international research results, this paper uses a combination method of bibliometrics and case analysis to review the current research status of inversion models for lake optical water quality parameters, including inversion techniques and progress of key optical water quality parameters such as chlorophyll a, inorganic suspended solids, and colored soluble organic matter. It also systematically reviews the latest research results on the impact of agricultural reclamation on optical water quality parameters of lakes, revealing the mechanisms by which agricultural activities affect lake water quality through pathways such as nutrient input, particulate matter input, and organic matter accumulation. Furthermore, through typical lake case studies (e.g., lakes in different climate zones, land use structures, and reclamation history backgrounds), the specific impacts of heterogeneity in agricultural reclamation structures on lake optical water quality parameters is explored, providing a scientific reference for lake ecological protection and sustainable agricultural development.

The quantitative assessment of wetland water purification functions is important for wetland restoration and water environment management. Based on the literature review, the purification mechanisms of wetlands for suspended solids, organic matter and nutrients have been summarized. The types, advantages and disadvantages, and limiting factors of constructed wetlands were analyzed. The functions of constructed wetlands in purifying new pollutants and reducing greenhouse gas emissions need to be further enhanced. In addition, the quantitative assessment methods for the water purification function of natural wetlands have been summarized, and the driving factors and limiting factors of the hydrological, hydrodynamic and vegetation modules in the numerical simulation have been sorted out. Additionally, a notable contribution of this review is its focus on the advantages of assessing water purification functions from the perspective of wetland complexes within a watershed. This approach provides valuable insights for establishing appropriate pollutant concentration control thresholds, which are particularly relevant in the context of wetland ecological restoration projects, comprehensive water quality improvement efforts across entire watersheds, and the planning and implementation of water transfer projects for lake wetlands. Finally, the review proposes future research directions based on an analysis of current research trends and identified gaps in the field of wetland water purification studies. It suggests a strategic shift in focus from single wetland research to a broader watershed scale perspective that considers wetland complexes. The review also advocates for increasing the density of data monitoring in key water quality areas, establishing long-term and large-scale ecological databases, and developing integrated models of large-scale wetland complexes. These initiatives are conducive to enhancing the ecological construction level of the entire river watershed in China and the water purification capacity of wetlands.

Agricultural nitrogen pollution has become a leading cause of non-point source pollution, resulting in widespread water quality deterioration including eutrophication, nitrate contamination of groundwater, and the formation of black and odorous water bodies. These adverse environmental impacts threaten aquatic ecosystems, public health, and hinder the advancement of rural ecological civilization. As agricultural production intensifies and expands, especially in rural areas lacking centralized treatment infrastructure, developing effective and sustainable nitrogen removal technologies is imperative for environmental protection. Constructed wetlands (CW) have been widely adopted as cost-effective, eco-friendly wastewater treatment systems that integrate physical, chemical, and biological processes for pollutant removal. Their low operational cost, landscape compatibility, and ability to support plant-microbe interactions make them particularly suitable for decentralized rural wastewater treatment. However, traditional CW often exhibit limited nitrogen removal efficiency and instability due to variable hydraulic loading, seasonal temperature fluctuations, and low carbon-to-nitrogen (C/N) ratios, which impede microbial nitrogen transformation processes. This review focuses on overcoming the challenges of nitrogen removal in CW by integrating functional substrates, including biochar, iron-based materials, and microbial fuel cells (MFC). These substrates enhance CW performance by improving substrate physicochemical properties, stimulating microbial communities, and facilitating nitrogen transformation under diverse environmental conditions. Biochar, produced by pyrolysis of biomass, is a porous carbonaceous material with high surface area and abundant functional groups, promoting pollutant adsorption and providing habitats for microorganisms. It improves redox potential and simultaneously supports aerobic nitrification and anaerobic denitrification. Iron-based materials, such as zero-valent iron and ferrous oxides, play crucial roles in redox reactions, facilitating denitrification and anaerobic ammonium oxidation (anammox). They also aid phosphorus adsorption and immobilize heavy metals, improving overall water quality. Combined application of biochar and iron synergistically enhances substrate stability and microbial diversity, promoting efficient nitrogen cycling and stronger plant-microbe interactions. MFC introduce bioelectrochemical functions by enabling extracellular electron transfer and electricity generation through microbial metabolism. They increase nitrogen removal efficiency, especially under low carbon availability, by stimulating microbial cooperation and redox activity. Though MFC effects on plant growth are limited, they provide added value by generating renewable energy to support system operation in off-grid rural settings. Furthermore, the use of these functional substrates helps to mitigate greenhouse gas emissions commonly associated with nitrogen cycling in wetlands, thereby contributing to climate change mitigation efforts. Their incorporation into CW design not only improves nitrogen removal but also enhances the overall ecological sustainability of treatment systems. Recent advances have demonstrated that combining these substrates with optimized operational parameters can significantly extend the lifespan and effectiveness of constructed wetlands, reduce maintenance costs and improve resilience to environmental fluctuations. his review synthesizes recent advances in the use of functional substrates for CW enhancement, elucidating their mechanisms, advantages under stress conditions, and practical implementation strategies. The integration of biochar, iron, and MFC offers a comprehensive and innovative approach to mitigate agricultural non-point source nitrogen pollution. Ultimately, this strategy improves nitrogen removal efficiency, system resilience, and sustainability, contributing significantly to water resource protection and rural ecological civilization development across diverse geographical regions worldwide with sustainable way.

Spartina alterniflora is a widely recognized invasive species that poses significant threats to native ecosystems. Its successful invasion is closely linked to its allelopathic effects, which involve the release of chemical compounds that influence the growth and physiological processes of neighboring organisms. This review comprehensively summarizes the classification of allelochemicals produced by Spartina alterniflora and explores the multiple mechanisms through which its allelopathic effects operate. The allelopathic substances secreted by Spartina alterniflora include organic acids, flavonoids, coumarins, alkaloids, and other secondary metabolites, primarily released through root exudates, leaching, and decomposition of plant residues. These compounds interfere with nutrient and water uptake in native plants by disrupting root function, thus limiting their access to essential growth resources. Moreover, Spartina alterniflora allelochemicals inhibit photosynthesis and respiration by damaging chloroplast ultrastructure and reducing photosynthetic pigments, stomatal conductance, and transpiration rates in native plants such as mangroves and herbaceous species. Additionally, these chemicals affect enzyme activities and cell membrane permeability, altering antioxidant enzyme systems (e.g., superoxide dismutase and peroxidase) and increasing lipid peroxidation markers, thereby compromising plant physiological function. The allelopathic effects extend beyond plants, impacting soil microbial communities by reducing the colonization of beneficial mycorrhizal fungi and altering microbial biomass and nutrient cycling processes, particularly carbon and nitrogen dynamics. These microbial changes negatively affect soil health and nutrient availability, further influencing plant community structure.The invasion of Spartina alterniflora also disrupts benthic animal communities in coastal wetlands, leading to declines in species diversity and richness of mollusks and nematodes. This is partly attributed to chemical changes in the sediment environment induced by allelochemicals released into the rhizosphere and litterfall, which alter food web dynamics and nutrient cycling in these habitats.Interestingly, Spartina alterniflora exhibits autotoxicity, where some allelochemicals produced inhibit its own seed germination and seedling growth, affecting its population dynamics. However, most research has focused on its heterospecific allelopathic interactions, and further studies are required to elucidate the mechanisms and implications of its autotoxicity.The allelopathic interaction between Spartina alterniflora and native plants is bidirectional. Certain native species such as Phragmites australis (common reed) and mangroves release compounds that suppress Spartina alterniflora growth, indicating complex chemical interactions that could be leveraged for ecological management. In addition to ecological impacts, Spartina alterniflora allelochemicals have practical applications. Extracts from this species demonstrate inhibitory effects on harmful algal blooms, such as Microcystis aeruginosa and Prorocentrumdonghaiense, through oxidative stress induction and disruption of photosynthetic systems. Moreover, flavonoids isolated from Spartina alterniflora possess anti-inflammatory properties and have been explored for cosmetic applications, suggesting potential economic value.Future research should broaden the scope to include effects on lower plants, fungi, soil biochemical properties, and animals, and investigate environmental factors influencing allelochemical production and release. Advanced analytical methods are needed to isolate and identify allelochemicals, while genetic and molecular studies could clarify regulatory mechanisms. Exploring integrated management strategies combining biological, chemical, and physical methods is essential to control Spartina alterniflora invasions while harnessing its beneficial properties. Overall, this review provides a comprehensive understanding of the allelopathic roles of Spartina alterniflora in invaded ecosystems, offering critical insights for ecological restoration and invasive species management.

As ecosystems with the highest biodiversity and ecological roles in the world, wetlands are confronted with a growing number of environmental pollution problems, especially heavy metal contamination, which has emerged as a crucial area of study. As a result, it has become essential to preserve wetland ecosystems. Plants, the fundamental component of constructed wetlands, are extensively utilized in the treatment of heavy metals in effluent, industrial wastewater, and residential sewage since they are low cost, low risk of secondary environmental damage, and superior ecological benefits for the environment. They play an important role in the purification of water bodies. Applying phytoremediation technology effectively requires an understanding of the mechanisms behind plant-based heavy metal remediation. This is crucial for improving the effectiveness of heavy metal pollution remediation in wetlands and lowering ecological concerns. This study examines recent local and international studies on the use of wetland plants for heavy metal pollution remediation. The importance of phytoremediation in wetland restoration is highlighted as it explores the capacities and processes of common wetland plants in the buildup and removal of heavy metals. Research shows that common plants in China and overseas, such as Phragmites australis, Typha orientalis, Thalia dealbata, and Myriophyllum verticillatum, have potent remediation abilities for wetland soils contaminated with heavy metals. Through a multitude of processes, including the release of root exudates (Res) into the rhizosphere environment, the formation of iron plaques on root surfaces, and radial oxygen loss (ROL), plants improve their capacity to accumulate heavy metals. Specifically, by releasing root exudates and causing radial oxygen loss, plants change the rhizosphere's pH, redox potentials, and microbial activities. It alters the solubility and mobility of heavy metals and encourages plant absorption of them. In addition, plants can form iron plaques on their roots to fix heavy metals and prevent them from entering the plant and causing toxicity. Heavy metals enter plant tissues, bind to phytochelatins to form heavy metal-phytochelatin complexes, and are subsequently carried into vacuoles by specific metal transporters, among which are cation diffusion facilitators (CDF), metal transporter P1B-ATPases, and iron-regulated transporter-like protein (ZIP). Furthermore, by controlling the activity of antioxidant enzymes like superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidases (APX), and catalase (CAT), plants can be used to increase their resistance to heavy metal toxicity under heavy metal stress conditions. This provides an efficient antioxidant defense mechanism that eliminates an excessive amount of reactive oxygen species (ROS), reducing the oxidative harm that reactive oxygen species inflict. Future research should focus on the application of genetic engineering and integrated remediation technologies that will enhance both the effectiveness of phytoremediation and its practicality when dealing with wetland heavy metal contamination.

Under the background of environmental protection, constructed wetland, an ecological technology, is widely used in advanced treatment and ecological purification of various surface water bodies because of its low carbon, low consumption and high efficiency. Plants are considered to be important parts of constructed wetlands and play an important role in the process of water purification. Due to the growth characteristics of wetland plants, if the withered wetland plants can not be harvested in time, they will lead to secondary pollution, and even cause wetland blockage, which will affect the stable operation of wetland system. This paper summarized the influence of plant harvesting on the operation effect of constructed wetland system, analyzed the mechanism of plant harvesting affecting pollutant removal, and finally summarized the harvesting management strategies of different kinds of plants. This paper makes up the blank of this part through narration, which will better guide the harvesting process of constructed wetland plants. The seasonal fluctuation of plant harvesting on water quality is significant. Harvesting in spring and summer can stably improve the removal effect of pollutants such as chemical oxygen demand and total nitrogen in the system, while harvesting in autumn and winter is beneficial to the removal of total phosphorus and ammonia nitrogen, but the impact on chemical oxygen demand and total nitrogen fluctuates greatly. In terms of plant species, harvesting submerged plants is more conducive to removing four conventional pollutants (chemical oxygen demand, total nitrogen, total phosphorus, and ammonia nitrogen) compared to emergent plants, which facilitates better purification of constructed wetland water bodies. At the same time, through the second excavation of the article, it is found that there is a certain correlation between wetland plant species and seasons during harvesting. In addition, harvesting not only directly affects the productivity and biological characteristics of plants, but also indirectly affects the physical and chemical environment and microbial metabolism process of wetlands by changing the oxygen secretion level of plant roots and the activity of substrate enzymes, thus affecting the plant-microorganism-substrate coupling effect and the geochemical cycle process of pollutants, which makes the change of water purification efficiency in constructed wetlands. The influence of plant harvesting on the operation of constructed wetland mainly depends on harvesting time, harvesting mode, harvesting frequency, harvesting degree and plant species. When harvesting plants, appropriate harvesting strategies should be selected according to plant types and actual conditions of constructed wetlands, striving to achieve the optimal solution.

Investigating the characteristics and mechanisms of soil organic carbon storage in the drawdown zone of reservoirs under periodic water level variations is of great significance for accurately understanding the eco-environmental effects of reservoirs and assessing their carbon sink function. Water level fluctuations in the drawdown zone of reservoirs could disrupt the formation and stability of soil aggregates, and also affect the binding of soil minerals and organic carbon as well as the structure and function of microbial communities, thereby regulating organic carbon sequestration. However, the soil organic carbon content in the drawdown zone is influenced by complex environmental factors, and the dominant mechanisms of soil organic carbon sequestration in the drawdown zone vary under different environmental conditions. Currently, no consensus has been reached on the storage and distribution patterns of soil organic carbon in drawdown zones under periodic inundation and exposure. Research on the soil carbon sequestration mechanisms of reservoir drawdown zones remains relatively insufficient, while it is particularly necessary to elaborate on the dynamics of organic carbon and its regulatory mechanisms in these areas. This review summarizes the impact of water level fluctuations on the storage and distribution of soil organic carbon in the drawdown zone, and analyzes the physical, chemical, and microbiological mechanisms of soil organic carbon sequestration in the context of the special hydrological features of the drawdown zones. Future research should combine field sampling surveys with in-situ controlled experiments to deeply elucidate the mechanisms of soil organic carbon sequestration and their interactions in reservoir drawdown zones, thereby providing a scientific basis for the development of carbon sequestration models and carbon sink accounting in drawdown areas of reservoir.

Lake wetlands serve as critical carbon reservoirs and sources/sinks within the terrestrial biosphere, playing a crucial role in the global carbon cycle. China is endowed with extensive lake wetland resources, and enhancing the capability to monitor and estimate their carbon source/sink dynamics is critical for achieving the national goals of carbon peak and carbon neutrality. However, considerable uncertainties remain due to limited research on carbon flux monitoring and mechanistic understanding of carbon cycling processes in these ecosystems. To improve the understanding of carbon dioxide (CO₂) flux research in Chinese lake wetlands and enhance the accuracy of carbon source/sink assessments in terrestrial ecosystems, this review classifies inland lakes of China into five distinct regions, according to the geographical regionalization framework; they are Tibetan Plateau lakes, Eastern Plain lakes, Inner Mongolia-Xinjiang lakes, Yunnan-Guizhou Plateau lakes, and Northeast Plain and Mountain lakes. For each region, we synthesize the characteristic patterns of CO₂ fluxes and identify key drivers influencing CO₂ emissions, such as climate conditions, hydrological properties, sediment characteristics, vegetation coverage, and anthropogenic impacts. Also, we provide an overview of widely applied methodologies for monitoring and estimating CO₂ fluxes, e.g. eddy covariance systems, floating chambers, and remote sensing-based models. Furthermore, this study outlines the major challenges in current research, including spatial and temporal data gaps, methodological inconsistencies, and scaling issues from site-level measurements to regional estimates. We propose future research directions aimed at strengthening long-term monitoring networks, integrating multi-source data, developing mechanistic models, and improving carbon sequestration strategies. This synthesis is expected to offer a scientific foundation for the conservation and sustainable management of lake wetlands, as well as the enhancement of their carbon sequestration potential in the context of climate change mitigation.

In the context of "carbon peaking and carbon neutrality goals", the energy consumption of wastewater treatment process has gradually been paid attention, and the chemical energy contained in the wastewater has huge development potential. Constructed wetland-microbial fuel cell (CW-MFC) technology has the dual functions of reducing pollution and generating electricity, which was considered to be a promising water treatment technology. Taking advantage of the electrochemical performance of metal mineral matrix, improving CW-MFC to enhance power generation and pollution reduction has become the focus of research. Based on introducing the operating principles, advantage and disadvantage of CW-MFC and the main influencing factors, the strengthening effects of metal minerals on CW and MFC were analyzed respectively in this review. The enhancement mechanism of CW-MFC modified by metal mineral matrix in pollutant adsorption and removal by metal redox cycle, and metal minerals played a significant role in reducing internal resistance to enhance conductivity, enriching electroactive bacteria, and establishing microscopic mechanism to improve electrochemical performance through interspecies electron transfer. We revealed the phenomenon of organic carbon fixation by metal minerals in wetland, and proposed theoretical paths for organic carbon fixation in CW-MFC. Focusing on reducing the cost of CW-MFC and improving efficiency of power generation, pollution reduction and carbon sequestration, the exploration of improving CW-MFC with metal minerals was proposed, which provides a reference for the promotions and applications of CW-MFC.

As a critical natural ecotone and barrier between marine and terrestrial ecosystems, mangrove wetlands play an indispensable role in the capture and sequestration of atmosphere carbon dioxide (CO₂), as well as organic carbon in the marine environment. Carbon within mangrove wetland ecosystems is ultimately fixed through a series of biological processes and biogeochemical reactions and sequestered in three primary and stable forms: vegetation biomass (i.e., plant aboveground and belowground biomass), plant litters (such as leaves, branches and root, etc.), and soil organic carbon (SOC). In contrast, the export and emission of organic carbon from mangrove wetlands occur mainly through three dominant pathways: the fluxes of greenhouse gas (mainly CO₂ released via soil respiration and litter decomposition, and methane (CH₄) produced under anaerobic soil conditions), the feeding and activities of benthic fauna (such as crabs and snails, etc.), and the hydrological export of dissolved organic carbon (DOC) and particulate organic carbon (POC) into adjacent coastal waters via tidal flow and runoff. By synthesizing the research findings reported in relevant domestic and international publications over the past six years (2018—2023), we reviewed the advances in three key processes of mangrove wetland carbon cycling, including carbon sequestration (i.e., carbon storage, carbon density and carbon sequestration rate) and its influencing factors (e.g., plant, soil physical and chemical properties), as well as the main organic carbon processes (i.e., carbon input and carbon export) in the carbon cycle of mangrove wetlands. Based on the review, we propose two urgent scientific and practical issues that need to be addressed in the current ecological restoration of mangrove wetlands. The first issue is the restoration and enhancement of the carbon sink capacity of degraded mangrove wetlands. The second issue is the need to balance the relationship between conservation (which have high and stable carbon sink capacities and should be protected from disturbance) and the ecological restoration of degraded mangrove areas. To address these gaps, future research should: in-depth exploration of the interactive effects of biotic and abiotic factors on mangrove carbon processes; systematic investigation of the transformation mechanisms of carbon pools; quantitative evaluation of the carbon sink benefits of vegetation restoration; detailed evaluation of restoration processes of carbon sinks; research on the priming effects and roles of consumers (e.g., benthic fauna) in carbon dynamics. Our review could provide a scientific support for the protection and restoration of mangrove wetlands, mitigation of greenhouse effect, and achieving the goals of carbon emissions peaking and carbon neutrality.

With the deepening implementation of the Global Stocktake mechanism under the Paris Agreement, independent verification and high-efficiency quantification of greenhouse gas emission inventories have emerged as critical scientific and operational requirements in international climate governance. Although the first-generation shortwave infrared hyperspectral carbon monitoring satellites represented by the GOSAT series, OCO series, and TanSat have validated the technical feasibility of high-precision space-based detection of XCO₂ and XCH₄, they are constrained by observation regimes relying on discrete point sampling or narrow-swath push-broom modes. Consequently, these missions exhibit significant limitations in spatiotemporal coverage efficiency, point source identification capabilities, and the separation of anthropogenic sources under complex background conditions. To address these bottlenecks, next-generation carbon monitoring missions exemplified by GOSAT-GW from Japan, CO2M from Europe, GeoCarb from the US, and TanSat-2 from China have comprehensively transitioned their payload architectures to wide-swath grating imaging modes. Furthermore, these missions have transcended the limitations of single polar orbits by adopting diversified orbital configurations, including Low Earth Orbit constellations, Medium Earth Orbit elliptical frozen orbits, and Geostationary Earth Orbit. By establishing systematic observation schemes integrating ultra-wide swath coverage, high-frequency revisit rates, and multi-species synergistic detection, these missions utilize aerosol synergy to enhance greenhouse gas retrieval accuracy. Additionally, they employ nitrogen dioxide as a tracer for anthropogenic emissions and Solar-Induced Chlorophyll Fluorescence to constrain natural carbon sinks, thereby effectively achieving precise separation of anthropogenic signals and detailed characterization of emission plumes. This technological leap will comprehensively enhance satellite-based capabilities for verifying anthropogenic emission inventories, providing consistent and traceable space-based observational support for the global verification of emission inventories.

As one of the most important greenhouse gases, carbon dioxide(CO₂) plays a critical role in regulating the stability of the global climate system and maintaining the balance of the terrestrial carbon cycle. Warming experiments, as a key approach to simulating climate warming scenarios, can reveal the influence mechanisms of temperature rise on key ecological processes such as soil respiration, carbon fixation and greenhouse gas emissions under controllable conditions.However, a comprehensive and systematic review and summary of the relevant research on the effects of warming experiments on CO₂ emissions is still lacking. Based on the Web of Science(WOS) database, English literatures with themes related to “Warming Experiment” and “CO₂” during the period from January 1, 2014 to December 31, 2024 were collected as the data sources. Knowledge graph analysis was carried out with the aid of Cite Space and VOS viewer software to construct the co-occurrence network of keywords, authors and research institutions, and systematically sort out the research status, hot topics and development trends in this field. The results indicate that, 1) since 2017, studies on warming experiments and CO₂ emissions have become increasingly active, with a steadily growing level of academic attention. 2) China, the United States, and Germany occupy dominant positions in this field, among which the Chinese Academy of Sciences and the University of Chinese Academy of Sciences rank highest in the number of published papers, forming a high-yield research cluster centered in China.3) Scholars such as Luo Yiqi, Josep Peñuelas, Zhu Biao and Yang Yusheng have made outstanding contributions and established several close linked internationalacademic cooperation networks.4) Research topics primarily focus on greenhouse gas emissions, temperature sensitivity, soil respiration, and carbon cycle, exhibiting a clear trend toward multi-scale, multi-gas, and multi-regional coordinated development. In the future, research should further deepen the exploration of underlying mechanisms, strengthen comparative studies across different climatic zones and ecosystem types, and elucidate the spatial heterogeneity and ecological feedback mechanisms of carbon flux changes driven by warming. At the same time, collaborative observations of multiple greenhouse gases and in-depth analysis of carbon-nitrogen coupling processes should be further promoted.

Fractional Vegetation Cover(FVC) is an important indicator reflecting the status of an ecosystem. To clarify current research progress and hot topics in FVC studies, we conducted bibliometric and visualization analysis on relevant studies. Results indicate that the number of academic works has grown significantly in recent years both in China and abroad. China has produced the highest volume of research, while studies from the United States and other western countries demonstrate greater academic influence. Key research areas include vegetation modeling, utilization of diverse remote sensing data sources, FVC status in diverse ecosystems, vegetation responses to climate change, and indicators for FVC estimation. Thematic evolution reveals that early studies primarily focused on fundamental research in ecology and meteorology, as well as mechanisms of climate-vegetation interactions. In recent years, research hotspots have shifted toward FVC model coupling and validation, climate change and ecological restoration, and improvements to FVC algorithms. Comparing themes in Chinese and foreign-language journal publications reveals that foreign journals predominantly focus on global-scale remote sensing monitoring and optimization of FVC remote sensing inversion methods. Chinese language academic works majorly emphasize temporal and spatial patterns of FVC within China and their underlying response mechanisms, frequently incorporating meteorological indicators, topographic types, and land-use changes into analyses. This study analyzes the development of FVC research, summarizes the limitations of existing research, and looks forward to future research directions, aiming to provide a reference for future ecological environment restoration, climate change response, urban planning, and sustainable development.

Rubber antioxidants p-phenylenediamines（PPDs）and their quinone derivatives（PPDQs）, as a class of new pollutants,have been widely detected in various environmental media and have gar-nered significant attention due to their acute toxicity to aquatic organisms．Studies have shown that PP-Ds and PPDQs can bioaccumulate and undergo metabolism in plants,animals,and humans,ultimately posing risks to ecosystems and human health．However,research on their biotransformation remains scarce．This review systematically summarizes the current pollution status of PPDs and PPDQs in the at-mosphere,water bodies,soil,and biota．It particularly focuses on summarizing their biotransformation pathways,metabolites and enzymatic mechanisms within fish,rats/mice,and humans．The biotransfor-mation of PPDs and PPDQs primarily involves Phase I metabolism catalyzed by cytochrome P450 en-zymes（such as hydroxylation,N-dealkylation,dehydrogenation）,followed by Phase II metabolism in-volving conjugation reactions with endogenous molecules．This review provides scientific basis for a dee-per understanding of the environmental fate and ecological/health risks associated with PPDs and PP-DQs．

Studies on the relationship between topsoil pollen assemblages and modern vegetation have an invaluable role in historical plant re-establishment and ancient environment reconstruction．On the basis of this,this study summarizes the hot frontiers and trends of topsoil pollen research in southern China,comparatively analyzes the characteristics of topsoil pollen assemblages in the three provinces of southern China as well as the application areas of topsoil pollen research in southern China and draws the following conclusions：1）The earliest article of CNKI on the study of topsoil pollen in southern Chi-na appeared in 1978,with a general upward trend in the number of articles published;the earliest arti-cle of WOS appeared in 2001．2）In the literature of CNKI,we mainly focus on the study of the rela-tionship between pollen and paleoclimate and the relationship between pollen and human activities;In the literature of WOS,we focus on the correspondence between surface sediments and vegetation,and the response of topsoil pollen to climate change．3）A comparison of the topsoil pollen samples from the three provinces of southern China revealed that the percentage pollen content of conifers was highest in Guangxi（62.5%）,while the percentage pollen content of broad-leaved trees and shrubs was highest in the samples from Hainan,with an average as high as 73.7%．The percentage of pollen content of her-baceous species was the highest in the samples from Guangdong,with an average of 60.2%．The mean value of the percentage of ferns spores in the three provinces ranged from 15.5% to 35.5%．

In an era marked by accelerated globalization, informatization, and digital economy development, digital nomads as a group that practices a new mode of production and lifestyle characterized by remote work and high mobility, have rapidly emerged, profoundly impacting global labor market, tourism industry, and policy systems. Drawing on literature from the database of Web of Science, this study systematically reviews the trajectory of international research on digital nomads from 2003 to 2024. It identifies three major developmental stages: the “Technological foundation period” (2003-2013), the “Lifestyle and identity formation period” (2014-2019), and the “Institutional response and critical deepening period” (2020-2024). Current scholarship has expanded beyond remote work to encompass community formation, spatial practices, and institutional adaptation, reflecting growing interdisciplinary complexity. The study highlights key implications for contextualization within China: (1) from the conceptualization aspect, a tripartite typology of high-mobility, regional-mobility, and long-term-residence digital nomads was constructed to better capture the low mobility and deep local embeddedness observed in China. (2) From the community research aspect, revealing the “rurality turn” in Chinese digital-nomad clusters and highlighting the emerging pathway of “digital nomads + rural revitalization,” with particular attention to how online-offline coordination and local social networks shape settlement stability and community governance. (3) From the policy-making aspect, a national-level, integrated institutional design was advocated that aligns identity recognition, social-security portability, and tax coordination to address systemic barriers faced by digital nomads. Thus, this study constructs an integrated conceptual framework for digital-nomad research and helps to fill key gaps in theoretical paradigms, comparative evidence, and policy tools within the Chinese scholarly landscape.

Necessity and sufficiency analysis aids in deciphering complex tourism management phenomena. However, its theoretical application and technical implementation in empirical research remain significantly inadequate, often leading to misuse. This paper systematically reviewed and critically evaluated the literature on necessity and sufficiency within tourism research. The study reveals that: (1) existing research heavily concentrates on tourist behavior, extending to resident behavior, employee behavior, and economic management; however, analyses of necessity and sufficiency for key entities such as tourism destination systems and macroeconomic levels remain markedly insufficient. (2) Methodologically, while fsQCA is widely adopted alongside NCA to assess necessity, confusion in method integration and operational irregularities persist in their combined application. (3) Variable selection predominantly relies on behavioral theories, while explanations for nonlinear combinations of multiple antecedents and complex causal relationships primarily draw upon complexity and chaos theory. However, research has insufficiently analyzed the interactive mechanisms among antecedent variables. Future studies should not only deepen the focus on necessity analysis but also extend necessity and sufficiency analyses to broader topics. Additionally, efforts should be made to refine analytical frameworks and strengthen theoretical foundations.The integrated theoretical framework constructed in this paper provides an operational methodological guide and a deepened theoretical perspective for future exploration of the relationship between necessity and sufficiency in the tourism field.

Tourist green consumption behavior is a critical pathway for achieving sustainable tourism development. This study systematically reviews relevant literature in both Chinese and English and, from the theoretical perspective of a “dynamic process and closed-loop system”, proposes a three-stage conceptual core for tourist green consumption behavior. It clarifies the influencing factors at each stage to explain the transition mechanisms between them, thereby constructing an integrated research framework. The main findings are as follows: (1) tourist green consumption behavior is a dynamic concept characterized by feedback cycles, which can be divided into three stages: “Intention → Behavior → Aftereffect.” (2) The development of this behavior is influenced by multiple internal and external factors, and its evolution materializes as a three-stage transformation mechanism: “Attitude-Behavior Translation → Behavior Maintenance → Intention Regeneration.” (3) The integrated research framework of “theoretical perspective, conceptual definition, influencing factors, and outcomes” for tourist green consumption behavior takes the “three-stage, three-transformation” process-mechanism as its logical thread. It incorporates multiple behavioral theories, such as the theory of planned behavior and social cognitive theory, to explain its transformation processes, and employs a mixed-methods approach for validation. Consequently, this study provides a systematic approach to overcome the fragmented perspectives prevalent in existing research, offering significant insights for deepening the theoretical understanding of tourist green consumption behavior and guiding managerial practices.

Given the increasing demand for professional tourism planners, many peers without tourism-education background have turned to tourism-planning operations. This study explores the generalized pathway of “cross-disciplinary knowledge updating” by interviewing 25 tourism planners focusing on their “learning-by-doing” experiences. The research findings indicate: (1) the knowledge updating process for cross-disciplinary tourism planners typically goes through three stages: “methodological”, “epistemological” and “ontological” knowledge updating. The objective of knowledge-updating in these stages can be respectively viewed as matching existing planning tools with tourism-specific needs at the micro level, understanding the operational logic of tourism businesses at the meso-level, and balancing multi-value orientations of tourism development at the macro level. (2) At each stage, the primary motivation for cross-disciplinary knowledge update stems from perceived knowledge gaps encountered while undertaking planning projects at different scales. Planners must engage in a contextualized “acquisition-absorption-application” process to better addressing perceived knowledge gaps and spontaneously re-build corresponding tourism-planning knowledge systems. (3) Whether tourism planners can upgrade knowledge systematically from “layman” to “expert” status depends on their ability across different stages to: Accurately identify professional knowledge gaps and locate appropriate knowledge sources, adopt suitable strategies to translate and absorb new knowledge, and employ suitable strategies within multi-stakeholder bargaining frameworks to validate, apply, and disseminate new knowledge. This study proposes a cross-disciplinary knowledge updating process for tourism planners, providing theoretical and methodological support for cultivating cross-disciplinary talents in the practice of multi-industry integration.