Clarifying the essence of regional ecological and environmental problems is the key to scientifically promote ecological construction in the agro-pastoral ecotone on the Loess Plateau. We summarized the latest progress of relevant research, and combined over 30 years of observation and research at the Shaanxi Shenmu Erosion and Environment National Field Scientific Observation and Research Station, proposed that water scarcity and unreasonable vegetation restoration were the main problems facing ecological construction in the agro-pastoral ecotone of the Loess Plateau. There are two forms of soil erosion in this area, water erosion and wind erosion. In terms of water erosion, we should restore grassland according to the vegetation zone and engineering measures should be transferred slopes to terraced fields to achieve soil and water conservation and water source conservation functions. In terms of wind erosion, vegetation restoration should focus on shrubs and grasses with low water consumption. Coarse soil remediation should be used in the engineering measures to control desertification, and the sandy land could be completely changed through combining the construction of new energy bases and modern agriculture. The agro-pastoral ecotone of the Loess Plateau should be classified and managed according to the geomorphology and water-soil resource characteristics of the loess and aeolian sand areas, with the focus of management directed at addressing the root causes, to achieve high-quality development of the regional ecological environment.

In the karst region of Southwest China, surface soil layer is shallow and discontinuous, coupled with the concealment, complexity, and high heterogeneity of underground fracture structure, making the hydrological processes significantly different from other types of landforms. Due to a lack of comprehensive understanding of the impact of spatial variability in the vegetation-soil-rock composite structure on infiltration and runoff generation, the interaction mechanisms between vegetation and hydrological processes in the critical zone are unclear. We systematically reviewed the main advancements and challenges in current research from three aspects: the characterization of critical zone, analysis of multi-interface runoff processes, as well as plant water use strategies and their eco-hydrological effects. Future research should focus on the eco-hydrological processes of the continuum of vegetation-soil-epikarst system. This includes analyzing the spatial characteristics of vegetation-rock-soil and their regulatory mecha-nisms on multi-interface hydrological processes, elucidating the driving and feedback effects of hydrological processes on vegetation succession, and clarifying the eco-hydrological effects of vegetation restoration at different scales. These works would provide a scientific basis for enhancing the stability of vegetation restoration and establish a scientific evaluation system for its effectiveness in the karst region of Southwest China..

Realizing a modernization of harmonious coexistence between humans and nature is the core content of current ecological civilization construction. Ecology is an important scientific foundation for ecological civilization construction. It is urgent to explore new ways to enhance the perception and regulation of nature, which would contribute new theories and methods to the modernization of harmonious coexistence between humans and nature. By fully leveraging modern technology to empower human senses, ecology is rapidly expanding in the form of modernized perception methods, providing several new ways for humans to deeply perceive nature and gradually achieving the modernization of the discipline's development. Under such a background, I argued that ecology should change the current adaptive ecosystem management paradigm that starts from nature conservation and establish a new scientific method system to conduct more precise mutual feedback regulation of the relationship between humans and nature. I proposed a harmonious ecosystem management paradigm that starts from human sensory satisfaction, takes ecosystem services as the link, comprehensively considers supply and demand balance and input-output, and fully cross-links various human sensory experiences with various ecosystem services to precisely regulate the harmonious relationship between humans and nature. The establishment of this new paradigm depends on how modern techno-logy promotes the future development of ecology, requires interdisciplinary integration from natural science to social science, and relies on extensive practice by government departments.

Landscape ecology is generally classified into the realm of macroecology and placed in a relatively high hierarchical level in ecological studies, which is above molecular ecology, individual ecology, population ecology, community ecology, and ecosystem ecology, yet below regional ecology and global ecology. In practice, however, landscape ecological research is not confined to macroscopic spatial scales but presents multi-scale characteristics. We systematically elaborated the multi-scale attributes and characteristics involved in landscape ecological studies from landscape pattern analyses, the coupling relationships between landscape patterns and processes. We further analyzed the fundamental principles to be followed in scale selection for landscape ecology research, as well as the associated issues and challenges faced. When selecting a scale, it is essential to consider the alignment with research objectives, the sensitivity of the research subject, the suitability of research units, and the compatibility of research data. Due to the knowledge limitation on scale multidimensionality and its spatiotemporal complexity in landscape ecological research, choosing an appropriate scale has significant challenges. For example, how to balance the relationship between grain size and extent, temporal and spatial scale, scale and data availability, has become key issues and challenges in scale selection for landscape ecological studies. We discussed the practical issues concerned in typical landscape pattern and process studies, which would provide references for making scientifically sound and rational scale selections in related research endeavors.

Plants contribute significantly to ecosystem primary productivity, serving as the basis of material cycling and energy flow. How to improve the accuracy of ecosystem productivity predictions is a classic topic in ecology. For decades, researchers have employed radiation-based remote sensing models or big-leaf-based process models to predict the spatiotemporal variations in ecosystem productivity. However, large discrepancies among model outputs constrain our understanding of the carbon sequestration capacity of ecosystems under global change. Recently, plant functional traits, as key parameters in next-generation process models, have received extensive attention. However, the scale mismatch between traditionally measured individual-level traits and community-level productivity constitutes an important source of model uncertainties. To address these challenges, we introduced the classical engine power model from physics and developed a novel trait-based productivity (TBP) framework centered on the two-dimensionality of plant community traits (quantity traits and efficiency traits). Contrary to the traditional models, all parameters in the TBP framework were defined at the community scale, with environmental factors influencing ecosystem productivity both directly and indirectly by regulating plant community traits. On this basis, using an in situ multi-trait database of Chinese ecosystems (including leaf chlorophyll concentration, leaf area, specific leaf area, leaf dry mass, and leaf nitrogen and phosphorus concentrations), we used three empirical studies to demonstrate the application scenarios of TBP theory. The TBP framework effectively bridges the scale gap between traits at individual level and ecosystem primary productivity. This framework is compatible with massive spatial data generated by flux observations, hyperspectral sensing, remote sensing, machine learning technologies, thus holding considerable application potential. Currently, the TBP framework is at an early stage. Besides requiring further theoretical innovation and methodological improvement, it also necessitates extensive support and validation from ground-based and remote sensing data. This will lay the foundation for the development of new-generation mechanistic process models and effectively improve the prediction accuracy of ecosystem productivity.

The acceleration of the formation and development of new quality productive forces in the new era is an inevitable requirement for China’s high-quality development and an important historical mission for achieving socialist modernization and ecological civilization. We interpreted the contemporary connotation of new quality productive forces from the perspective of applied ecology, which refers to an innovative production capacity driven by the optimization and sustainable utilization of ecosystem services, promoting harmonious coexistence between humans and nature. Furthermore, we summarized the developmental trajectory of applied ecology, evolving from biological to social and finally to digital applied ecology, and explored its crucial role in fostering disciplinary and technological innovation as well as the allocation of production resources. Looking ahead, applied ecology should take ecosystems as its core and strengthen the integration of biological cognition and human activities. It should focus on the development of ecological theories for new quality productive forces, the construction of methodological systems that integrate green development and innovation, and the practical application of ecological scenarios for new quality productive forces, which all contribute to achieving the green and healthy development of ecosystems. To promote the development of new quality productive forces through the interdisciplinary integration of applied ecology would provide ecological support for harmonious coexistence between humans and nature.

There are a variety of toxic and widely distributed organic contaminants in soils, threatening ecological safety and human health. Bioremediation technology primarily addresses soil pollutants through enzymatic reactions of microorganisms. Nevertheless, the effectiveness of bioremediation technology is much lower when treating contaminated soils with multiple organic pollutants. The combination between microbiome technology and bioremedia-tion is one of the hot topics in the research area of soil remediation. In recent years, there are rapid progresses in bioremediation research based on genomics, transcriptomics, proteomics and metabolomics. Based on technology of genomics, the composition of soil microorganisms could be analyzed, identified, eliminated, and finally functional microbiome can be screened. Consequently, functional microbiome could be constructed and targeted according to the characteristics of organic pollutants. Transcriptomics could help discover unknown functional genes, and explore new pathways for organic pollutant degradation. Proteomics and metabolomics would help improve the degradation efficiency of organic pollutants. We reviewed the challenges in bioremediation of organic-contaminated soil, analyzed microbiome methods being used in bioremediation, and examined the principles and effectiveness of microbiome-based bioremediation with empirical studies. Currently, omics technology is still at its early stage in the field of organic soil contamination bioremediation, with more crucial data being needed. Utilizing microbiome methods for molecular operations, innovating organic-contaminated soil bioremediation systems and elucidating the restoration mechanisms will be the key for efficient application of bioremediation technologies.

Increasing the carbon sink capacity of terrestrial ecosystems is a primary strategy to mitigate climate change and achieve the “carbon neutrality” goal. Clarifying the status and future dynamics of carbon sink of terrestrial ecosystems in Northeast China is crucial for achieving “carbon neutrality” as this region is a core contributor to carbon sink in China's terrestrial ecosystems. Here, we systematically summarized current research on carbon sink of terrestrial ecosystems across Northeast China, including the measurements and spatial-temporal patterns of carbon sinks, driving mechanisms of carbon sinks, the assessments of carbon sink potential, and technologies for increasing carbon sequestration. There are substantial uncertainties in quantifying terrestrial ecosystem carbon sink in Northeast China due to differences in data sources and methods, especially for forest carbon sink measurements, ranging from 0.020 to 0.157 Pg C·a^-1. Carbon sink function depends on carbon exchange processes across plant-soil-atmosphere interfaces. The key pathways to enhance carbon sequestration in Northeast China under different temporal and spatial scales remains unclear. Improving terrestrial ecosystem quality is the key and core of carbon sequestration and sink enhancement. However, there is an urgent need to develop a multi-ecosystem collaborative carbon sequestration and sink enhancement technology system for the “dual carbon” goal. Future research needs to develop an accurate carbon sink measurement system that integrates multi-source data and multi-scale technologies to accurately assess the function and potential of carbon sink in Northeast China, focus on the multi-scale driving mechanism of carbon sink functions, develop new technical systems for coordinated enhancement of carbon sink for the Northeast terrestrial ecosystems, and carry out demonstrations of carbon sink enhancement technologies. These efforts will provide the scientific and technological supports for achieving the “carbon neutrality” goal.

To complete the life cycle, species exhibit corresponding functional traits in morphology, physiology, ecology, etc. The eigenvalues, variation, and distribution of functional traits are the functional components of biodiversity, namely functional diversity, could maintain the service function and healthy operation of ecosystems. The application of functional diversity broadens our understanding of biodiversity and its temporal and spatial variations, and provides a breakthrough to the problem of how to combine morphological structure with ecological function. I reviewed the research process of functional diversity from the perspective of proposing, calculating, and applying the parameters of functional diversity, as well as the application of functional diversity from different purposes and perspectives. I put forward the challenges and countermeasures of related studies. In the future, researches should pay attention to establish a set of effective trait indicators, discover the internal and external mechanisms driving functional diversity variations, and map the redistribution of traits under environmental changes.

The turnover and stabilization of soil organic carbon are tightly associated with the properties of litter input. Due to the complexity of litter decomposition and the high heterogeneity of forest soils, there are considerable uncertainties about how soil minerals, microorganisms, and environmental factors jointly regulate the transformation and stability of litter-derived soil organic carbon. Here, we present an overview of the “microbial efficiency-matrix stabilization” framework centered on microbial metabolism and organic carbon transformation, as well as the new “microbial carbon pump” and “mineral carbon pump” theories in forest soil organic carbon transformation and stabilization. We specifically highlighted a differential mechanism of “organo-organic interfaces” from the “organo-mineral interfaces” in the effects on soil organic carbon accumulation. We further expounded the transformation processes and stability of soil organic carbon based on the “carbon material cycling” and “energy fluxes”, aiming to provide theoretical support for the research on carbon sequestration in forest soils.

Since the Industrial Revolution, human activities have led to a rapid and sustained increase in reactive nitrogen production, resulting in nitrogen enrichment at the Earth's surface and triggering many ecological and environmental issues. Stable isotopes are effective tools for tracing the sources and mechanisms of environmental processes. The nitrogen isotope values in surface environments integrate the isotope signatures of different nitrogen sources and the isotope fractionation effects of transformation processes. The composition of nitrogen isotopes can thus be utilized to trace the sources and cycling of nitrogen at the surface, aiding the development of strategies to reduce reactive nitrogen emissions, and assess the ecological effects of nitrogen enrichment. We reviewed the research progress on nitrogen isotope in the sources of reactive nitrogen in atmospheric systems, plant nitrogen utilization, and tracking of nitrogen processes in forest ecosystems. We further discussed how to gain a more systematic and accurate understanding of nitrogen cycle within and between the various spheres of the surface environment.

Territorial spatial planning could achieve the integration of various plans, resulting in a unified “multi-plan integration” map. Such planning emphasizes the efficient use of territorial spatial patterns and structures to ensure functional perfection, and serves as the spatial framework for building a modern socialist country, particularly in the areas of ecological security and ecological civilization. The past few decades have seen rapid advances in the development of landscape ecology in China. The core concept of “pattern-process-function” has gained significant progress and been widely applied in the initial phase of territorial spatial planning at various levels. We outlined the advancements in the territorial spatial planning system and the core research theories and technologies in landscape ecology. We discussed the progress and shortcomings of key theories and methods of landscape ecology in practical applications of territorial spatial planning, such as ecological security patterns, pattern and process, and scale effects. We proposed the future application of landscape ecology theories and technologies in territorial spatial planning, including overall ecological effects, scale effects, and regional ecological network optimization. Future developments in landscape ecology, especially research on the “human-place-ecology” coupling based on the latest Big Data and AI technology for sustainable development, will provide robust theoretical and methodological supports for the scientific formulation of territorial spatial planning in China.

For a long time, intercropping and rotation of leguminous with non-leguminous crops is widely used to reduce the application of nitrogen fertilizer and increase yield in agroecosystems. At present, most researchers considered that this management measure is helpful for reducing fertilizer consumption and increasing its efficiency, as it can improve nutrient supply of legumestonon-legumes, the spatial nutrient utilization efficiency by enhancing soil spatial heterogeneity, and improve soil structure and disease resistance. However, current theories cannot fully explain the positive effect of crop rotation and inter-cropping systems involving legumes. A large amount of hydrogen (H₂) can be produced as an obligatory by-product of nitrogenase responsible for nitrogen (N₂) fixation in the root nodules of leguminous plants. Despite of substantial amounts of H₂ enriched in the rhizosphere of legumes, only a minor proportion of H₂ is found to leak to soil surface. Increasing evidence showed that most H₂ released in soil is immediately depleted in the surrounding of N₂-fixing nodules by H₂-oxidizing bacteria (HOB) thriving in soil. HOB can use H₂ as an electron donor to assimilate and fix CO₂ through redox reactions to synthesize cellular substances and consequently promote plant growth. To date, however, little is known about the biological mechanism and ecological process behind the “hydrogen fertilizer effect”. Therefore, we review the H₂-induced plant growth-promoting effects and its microbiological mechanisms. Our aims were to explore a new way for enhancing agroecosystem production, and to provide scientific basis for future utilization of H₂ in agricultural production practices.

Species distribution models (SDMs) are valuable tools in predicting species distribution ranges and the suitable habitats, which are based on environmental conditions and species distribution data. These models encompass correlative models, mechanistic models, and mechanistic-correlative models. In the field of marine science, SDMs have been extensively used for predicting the spatial distribution patterns of various marine organisms including fish, mammals, algae, et al. However, the application of SDMs in predicting the distribution of macrobenthos remains scarce. Understanding the distribution of macrobenthos, the integral components of marine ecosystems, has significant implications for ecological conservation and resource management. We reviewed common methodologies employed in SDMs and presented case studies using different models to predict the distribution patterns of marine macrobenthos. Further, we emphasized the use of correlative and mechanistic models to analyze the impact of climate change on the spatial distribution of marine macrobenthos. Finally, we discussed the challenges and prospects associated with SDMs. With the advances in remote sensing technology and modeling techniques, SDMs are becoming increasingly pivotal in marine ecological research, which could offer a robust scientific foundation for addressing climate change and preserving marine biodiversity.

Termites, as a kind of nesting social insects, are often confused as worldwide “pests” because some of their groups have great destructive effects. The vast majority of termites can regulate ecosystem functions and ser-vices by participating in biogeochemical cycles, known as “ecosystem engineers”. We reviewed studies on the effects of termites on the physical, chemical and biological characteristics of mound soil ecosystems and the composition and diversity of plant communities. Termites could form unique soil “biogenic aggregates” and “resource heterogeneity patches”, which affect microbial community structure, extracellular enzyme activity, physicochemical property and greenhouse gas emission, thereby affecting plant growth, community composition and structure, and vegetation productivity. However, this effect significantly differed among termite groups and functional groups, and was dependent on regional soil environment and microclimate conditions. Meanwhile, termite-mound could effectively improve ecosystem adaptation or resistance to environmental stress through the above process. Future research should focus on the following directions: 1) studying the trophic cascading effect of termite-centered soil multilevel biological network and the potential effect on biogeochemical cycle from microscale (aggregate level) to macroscale (landscape level); 2) exploring the potential of termite mound soil as a fertility amendment in tropical regions, and mining beneficial microbial functional genes to develop related products for termite control.

The Loess Plateau is renowned for its deep soil layer and rich in organic carbon (C). In recent years, numerous ecological restoration projects have been undertaken on the Loess Plateau, with consequence on the stability of soil organic carbon (SOC). The SOC stability is pivotal for its capacity to sequestrate and store C. However, comprehensive review on the characteristics of SOC stability and its mechanisms during vegetation restoration on the Loess Plateau is scarce. Therefore, we summarized the dynamics of SOC stability during vegetation restoration on the Loess Plateau, discussed the mechanisms of SOC stabilization, including mineral protection, physical protection, and biological mechanisms. Furthermore, we prospected the future development directions and research focus of SOC stability research during vegetation restoration on the Loess Plateau to provide scientific support for theory and technology of soil C sequestration and stabilization during vegetation restoration, and to provide scientific reference for achieving the “double-carbon” goals.

In the past decade, research on the relationships between the supply and demand of ecosystem services has been flourishing. To address issues such as the misuse of supply and demand concepts, methods, and results in current research, we proposed five key aspects that need to be considered to enhance the scientific rigor and practical value in assessing relationships between ecosystem service supply and demand. Firstly, it is essential to clarify the distinctions and connections between the concepts related to ecosystem service supply and demand, which are crucial prerequisites and starting points for assessing their relationships. Secondly, it is necessary to integrate relevant environmental standards or policy objectives to develop reliable methods for assessing the demand for ecosystem regulating services. Furthermore, it is important to properly address the modifiable areal unit problem by determining the most appropriate spatial scale and unit for evaluating relationships between ecosystem service supply and demand. Additionally, it is crucial to differentiate between quantitative and qualitative methods for characterizing (im)balances or (mis)matches between ecosystem service supply and demand, particularly avoiding the use of qualitative methods to represent quantitative relationships between supply and demand. Lastly, it is imperative to integrate ecosystem service flows into the assessment of supply and demand relationships, and evaluate the dynamic supply and demand relationships of regional ecosystem services from a coupled “supply-flow-demand” perspective.

Soil organic carbon (SOC) represents the largest terrestrial organic carbon pool and plays an important role in mitigating global climate change. Warming can change the stabilization process and the balance of inputs and outputs of the SOC pool, thereby affecting the content, fraction, and chemical structure of SOC. It has become a research hotspot to reveal the mechanisms underlying the effects of warming on SOC stability by analyzing the fraction and molecular structure of C. Here, we reviewed the warming effects on the SOC pool from three aspects, e.g., the content, fraction, and chemical structure of SOC. We also summarized the response of key ecosystem processes to warming, including plant productivity and community composition, microbial activity and community structure. We highlighted the importance of prospective and systematic research focusing on elucidating the microbial mechanism, identifying SOC source and turnover processes, establishing long-term dynamic networked experiments, and mining and optimizing key parameters in C cycle models. This would provide theoretical support for better understanding the change and mechanism of SOC under global warming and predicting the alterations of SOC pool under climate change.

Soil respiration, the main pathway for transferring terrestrial carbon pool to atmospheric carbon pool, is profoundly affected by the intensification in global precipitation variability in the context of climate change. Nowadays, variable controlling methods and field manipulation experiments are two main methods widely used to investigate the effects of simulated precipitation changes on soil respiration. Yet, due to the heterogeneity of soil properties, vegetation types, and the magnitude of precipitation change, there is substantial inconsistency in the conclusions of simulated precipitation change effects on soil respiration. Here, we analyzed data from domestic and foreign literature, and examined the effects of simulated precipitation change on soil respiration. Firstly, we described the response pattern of soil respiration to soil moisture fluctuation and pointed out that the magnitude and direction of the response of soil respiration to simulated precipitation change depended on whether soil moisture was optimally conditioned at different precipitation treatments. Second, we summarized the response patterns of soil respiration to symmetric increase and decrease in precipitation, which mainly included symmetric and asymmetric responses (positive and negative asymmetric). Meanwhile, the adaptation of plants and soil microorganisms to drought stress and soil oxygen limitation, as well as the reduction of organic substrates, were the main mechanisms accounting for the shifts of soil respiration response patterns to simulated precipitation change from symmetric to asymmetric responses. Third, we identified a significant effect of ambient climate on soil respiration in response to precipitation treatments as increasing duration of the experimental treatments. In addition, cumulative or buffering effects of ambient climatic conditions on precipitation treatment could affect the sensitivity of soil respiration along precipitation gradient by altering hydrothermal conditions. Finally, to accurately assess the implications of precipitation changes on soil carbon balance processes, we proposed three aspects of future precipitation effects on soil respiration for attention: 1) focusing on the phenomenon of “threshold effects” in the asymmetric response of soil respiration along precipitation gradients; 2) distinguishing the intrinsic mechanisms of autotrophic and heterotrophic components in soil respiration in response to precipitation changes; and 3) focusing on the impacts of intensified precipitation variability on soil respiration in the context of future climate extremes. In conclusion, with the intensified variability in global precipitation patterns, clarifying the response mechanism of soil respiration to precipitation changes is of great significance for accurately predicting and evaluating the alterations of soil carbon cycle processes and carbon balance in the context of global changes.

Tree growth includes primary growth and secondary growth. The growth activity and dormancy cycle of trees can affect forest productivity and carbon sequestration capacity. Therefore, it is of great significance to examine the effects of environmental conditions (e.g., photoperiod, temperature and water) on tree growth for understanding the responses of trees to climate change and predicting forest productivity and carbon sequestration capacity under the background of global climate change. We reviewed the effects of photoperiod, temperature and water conditions on the primary and secondary growth of trees, and revealed the physiological mechanisms underlying their impacts on the synchronization or asynchronization between primary and secondary growth of trees. The shortcomings of the existing research were pointed out. For example, less attention had been paid to the enrionmental response and adaptation of root growth, as well as the physiological mechanism of the effect of light, temperature and water on tree growth. Research on the growth of underground roots should be strengthened in the future, and more attention should be paid to the physiological changes in the process of tree growth affected by environmental factors. Furthermore, the source and sink limitation theory and the process-based prediction model should be improved, aiming to provide a scientific basis for predicting forest productivity and carbon sequestration capacity and putting forward scientific policies of forest management.