Exchanges of energy and matter between terrestrial biosphere and atmosphere and hydrosphere create critical feedbacks to Earth’s climates. To quantify how terrestrial ecosystems respond and feedback to global changes, terrestrial biosphere model (TBM) has been developed and applied in global change ecology during the past decades. In TBMs, myriad of biogeophysical, biogeochemical, hydrological cycles and dynamics processes on different spatial and temporal scales are represented. The TBMs have been applied on assessing and attributing past changes in terrestrial biosphere, and on predicting future changes and their feedbacks to climates. Here, we provide an overview of processes included in TBMs and TBMs applications on carbon and hydrological cycles, as well as their application on exploring human impacts on terrestrial ecosystems. Finally, we outline perspectives for future development and application of TBMs.

As the increasing pressure caused by climatic changes and human activities, the structure and function of terrestrial ecosystems are undergoing dramatic changes. Understanding how ecosystem processes change at large spatial-temporal scales is crucial for dealing with the threats and challenges posed by global climate change. Traditional field survey method can obtain accurate plot-level ecosystem observations, but it is difficult to be used to address large-scale ecosystem patterns and processes because of spatial and temporal discontinuities. Compared to traditional field survey methods, remote sensing has the advantages of real-time acquisition, repeated monitoring and multi spatial-temporal scales, which can compensate for the shortcomings of traditional field observation methods. Remote sensing can be used to identify the type and characteristic of ground objects, and extract key ecosystem parameters, energy flow and material circulation through retrieving the information contained by electromagnetic signals. Remote sensing data have become an indispensable data source in ecological studies, especially at the ecosystem, landscape, regional or global scales. With the emergence of new remote sensing sensors (e.g., light detection and ranging, and solar-induced chlorophyll fluorescence) and near-surface remote sensing platforms (e.g., unmanned aerial vehicle and backpack), remote sensing is entering the three-dimensional era and the observation platform become more diverse. These three-dimensional, multi-source and time-series remote sensing data bring new opportunities to fully understand ecosystem processes across different spatial scales. This paper reviews the advances of the application of remote sensing in terrestrial ecosystem studies. Specifically, this study focuses on the derivation of biological factors from remote sensing data, including vegetation types, structures, functions and biodiversity of terrestrial ecosystems. We also summarize the current status of the remote sensing technology in ecosystem studies and suggest the future opportunities of ecosystem monitoring in China.

Wildlife as one major group in ecosystem research and conservation management, play a critical role in regulating the structure and function of ecosystems and maintaining the health and balance of ecosystems. Scientific monitoring data are the basis for wildlife research, protection and management decisions. However, the wildlife diversity, their relationship and related mechanisms with the environment and ecosystem balance have been paid insufficient attention due to the limitations of traditional monitoring technologies. With the development and application of automatical and information technologies, wildlife monitoring technology has achieved great breakthroughs and changes. In this paper, we described four new technologies widely used for wildlife monitoring recently, including camera-trapping technology, Global Positioning System (GPS) tracking technology, DNA-barcode technology and next-generation sequencing technology. We introduced the basic concepts and principles, then summarized the advantages and major application progress of these four key technologies as well as the problems existing in the application. Finally, we discussed the trend of the wildlife monitoring technologies.

Microbiome is the combination of all microorganisms and their genetic information in a specific environment or ecosystem, which contains abundant microbial resources. A comprehensive and systematic analysis of the structure and function of microbiome will provide new ideas in solving the core issues in the fields of energy, ecological environment, industrial and agricultural production and human health. However, the study of microbiome largely depends on the development of relevant technologies and methods. Before to the advent of high-throughput sequencing technology, microbial research was mainly based on techniques such as isolation, pure-culture and fingerprint. However, due to the technical restrictions, scientists could only get limited knowledge of microorganisms. Since the beginning of 21st century, the revolutionary advances in the technology of high-throughput sequencing and mass spectrometry have greatly improved our understanding on the structure and ecological functions of environmental microbiome. However, the application of microbiomics technology in microbial research still faces many challenges. In addition, the descriptive studies focusing on the structure and diversity of microbiome have already matured, and the study of microbiomics is facing a critical transition period from quantity to quality and from structure to function. Hence, this paper will firstly introduce the basic concepts of microbiomics and a brief development history. Secondly, this paper introduces the related technologies and methods of microbiomics with their development process, and further expounds the applications and main problems of microbiomics technologies and methods in ecological study. Finally, this paper expounds the frontier direction of the development of microbiomics technology and methods from the technical, theoretical and application levels, and proposes the priority development areas of microbiome research in the future.

Biomarkers are biogenic organic compounds that carry the chemical structures specific to their biological sources and survive long-term preservation in environmental and geological systems. The abundance of biomarkers may indicate the relative contribution of specific biological sources to the natural organic matter while their chemical and isotopic compositions may also inform on the transformation stage of organic matter and the environmental settings. Compared with conventional bulk analysis, biomarkers offer highly specific and sensitive tools to track the sources, transformation and dynamic changes of natural organic matter components and have therefore been widely used in ecological and biogeochemical studies in the past decades. In particular, combined with ecosystem observations and control experiments, biomarkers have shown great potentials in revealing changes in microbial activity and carbon sources, soil organic matter dynamics, stabilization mechanisms and response to global changes. The recently-developed biomarker-specific isotope analysis also exhibits a great promise in revealing ecosystem carbon and nitrogen turnover and food web structures. This review summarizes several major categories of commonly used biomarkers, their analytical methods, applications in ecosystem studies and existing pitfalls, and discusses future directions of research to provide guidance for biomarker users in ecology and environmental sciences.

In the past several decades, the development of nitrogen (N) stable isotope techniques has improved the understanding of N cycling in terrestrial ecosystems. This review briefly introduced the history of N stable isotope techniques in studying N cycling in terrestrial ecosystems and summarized typical studies focusing on different aspects of ecosystem N cycling in recent years, including using 1) ¹⁵N natural abundance to identify plant N sources, indicate N status of ecosystems, and quantify N transformation rates; 2) ¹⁵N enriched tracers to study N fates, redistribution and gaseous loss from ecosystems. In the end, this review points out challenges and future applications of N stable isotope techniques on studying N cycling in terrestrial ecosystems.

Recently developed in recent decades, the carbon isotope tracing technology is one of the most reliable methods, which has been widely used in the study of carbon (C) cycling in terrestrial ecosystems due to its high specificity and sensitivity. Here, the principle, analysis method and application process of C isotope tracing technology in C cycling in terrestrial ecosystem have been reviewed. Four different methods are currently being used in laboratory or field conditions, including natural abundance method, Free-Air Concentration Enrichment (FACE) technology coupling with ¹³C dilution method, pulse and continuous labeling with ¹³C enriched CO₂, and labeling with ¹³C enriched substrates. Results of field experiments and lab incubation experiments employing carbon isotope tracing technology were combined in order to quantify the transformation and distribution of photosynthetic C in plant-soil system. Furthermore, these techniques also help to understand the contribution of plant photosynthetic C to soil organic matter, the stabilization of soil organic matter and its microbial mechanism, to illustrate the dynamic changes of soil organic carbon (SOC), evaluate the contribution of new and old organic C to soil C storage, and estimate the micromechanism of SOC input, conversion and the stabilization in terrestrial ecosystems. Carbon cycle is affected by climate, vegetation, human activities and other factors, and therefore it is imperative to further develop a sensitive, accurate, multiscale and multidirectional isotope tracing system by combining carbon isotopes with mass spectrometry, spectroscopy and molecular biological technology. We have summarized the coupled application of carbon isotope tracing technology and the insitu detection involving molecular and biological approaches, and discussed the existing issues of carbon isotope tracing technology.

Stable oxygen and hydrogen isotope analysis provides an important tool to trace, integrate or indicate water fluxes from leaf, whole-plant to ecosystem levels. Through measuring and analyzing the natural varitions in the hydrogen and oxygen isotope compositions of water from different components of ecosystem, we can partition evapotranspiration of ecosystem, determine source of plant water uptake, and study mechanism of leaf water isotope enrichment. As such, water isotope analysis has emerged as an indispensable technique to study the mechanism and ecological effects of different water cycle processes in ecosystem. In this paper, we briefly reviewed the history in development and application of water isotope analysis for terrestrial ecosystem studies, which then followed by more detailed introduction of the application principles and technical essentials. Furthermore, we reviewed progresses in diverse water-isotope based research field ranging from evapotranspiration partitioning, plant water uptake apportionment, sourcing of dew flux and precipitation vapor, to exploration leaf water isotope enrichment mechanisms and water-carbon coupling. Finally, we summarized technological and methodological challenges to be solved in the future ecological research, so as to fully realize the potential of water isotope analysis in various field of ecological research.

Massive fossil fuel burning and the rapid urbanization have caused significant increases in atmospheric carbon dioxide (CO₂) and ozone (O₃) concentrations. The increased gas concentration has significant impacts on the structure and function of terrestrial plants and ecosystems. Rising CO₂ concentration increased the plant growth and productivity, while elevated O₃ decreased grain yield and carbon sequestration capacity. The Free-Air Concentration Enrichment (FACE) is one kind of facility closest to the natural conditions for simulating effects of rising atmospheric gas concentration on ecosystems. FACE has been widely used in various ecosystems and provides key basis to understand the ecological progress in response to global change and parameters for risk assessment in terrestrial ecosystem models. In this paper, CO₂/O₃-FACE facility around world and their technology are reviewed. The advantages and disadvantages of the design of each FACE in different terrestrial ecosystems were discussed. The current status of global FACE facility and progress in research achievements are also introduced. Furthermore, the problems in running current FACE and the frontiers of scientific questions are also highlighted.

Due to the sharp increase in carbon emissions from human activities, global surface air temperature has increased significantly by approximately 1 °C since the Industrial Revolution, and it will continue to increase by up to 4 °C by the end of 21st century. This unprecedented climate change will not only affect the adaptation strategies of terrestrial vegetation, but also profoundly affect the structure and function of terrestrial ecosystems. The feedbacks of terrestrial ecosystem carbon cycling to warming is the key factor controlling the speed of future climate change. Therefore, a large number of ecosystem-scale field warming manipulation experiments have been conducted globally to study the carbon budget of terrestrial ecosystems and to improve the prediction accuracy of earth system models. However, due to differences in techniques and methods of these field warming experiments, results among different studies are difficult to compare and synthesize. This paper reviews the common techniques and methods of field warming manipulation experiments, including active warming and passive warming. It also summarizes advantages and disadvantages, applicable objects and related publications for these techniques and methods. Moreover, it briefly introduces future directions of field warming manipulation experiments—the next-generation field warming techniques, namely whole-soil-profile warming and whole-ecosystem warming, and calls for establishing a coordinated distributed network of field warming manipulation experiments using these techniques.

The exchange flux of greenhouse gases, such as carbon (CO₂, CH₄), nitrogen (N₂O) and water vapour (H₂O), is the core of material cycle in the ecosystem and the bond of interaction among geosphere, biosphere and atmosphere. The development of stable isotope infrared spectroscopy and mass spectrometry technology and methods makes it possible to measure carbon stable isotopic composition (δ ¹³C) and oxygen stable isotopic composition (δ ¹⁸O)(CO₂), δ ¹³C (CH₄), nitrogen stable isotope composition (δ ¹⁵N) and δ ¹⁸O (N₂O), hydrogen stable isotopic composition (δD) and δ ¹⁸O (H₂O), which realizes the observation of greenhouse gas and its isotope flux at the soil, plant and ecosystem scales in combined with chamber-based technology and methods for flux measurement. Taking the chamber-based technology and methods for CO₂ and its δ ¹³C flux measurement as an example, this review which summarizes the basic principle and classification of the flux measurement system, expounds the theory requirements and assumptions of system design, summarizes the application advance and problems of chamber-based technology and methods for flux measurement in soil, plants (leaf, stem, and root) and ecosystem scales from the field to indoor, and prospects the importance of precision and accuracy of gas analysis and measurement data and the representativeness of measurement data in chamber-based flux measurement.

Flux-gradient method and eddy covariance technique are classical micrometeorological methods, which observe fluxes of mass and energy. Flux-gradient method can effectively measure the greenhouse gas and isotope fluxes between ecosystem (or soil) and atmosphere although gas analyzer with high measuring frequency was not available or the fetch was small. Flux-gradient method can be viewed as an ancillary measurement and useful complement of eddy covariance technique. This paper reviewed from the following aspects: the fundamental theory, concepts and assumptions of flux-gradient method; the methods measuring the gradient of greenhouse gases and the theory on turbulent diffusion coefficients; the applications of this method in measuring greenhouse gas fluxes, especially on isotope fluxes, over various ecosystems including forest, cropland, grassland, wetland and water bodies. Finally, the considerations and suggestions were provided regarding the measurement on concentration gradients of greenhouse gases and isotopes, and the calculation of turbulent diffusion coefficients.

Carbon (C) and water cycles are the most critical processes in terrestrial ecosystems, which links the materials and energy flows through the pedosphere-biosphere-atmosphere integration. Most attention has been paid to the responses of C and water and their feedbacks to global climate change. Flux observation is the basic pathway to quantify the rate of material and energy exchange across soil-plant-atmosphere continuum. As an only technique can directly measure the carbon, water and energy fluxes between vegetation and atmosphere, eddy covariance (EC) technique has been considered as a standard method for flux observation internationally. With broad applications of EC technique on global C and water cycles, long-term flux observations provide scientific data on assessing ecosystem C sequestration capability, water and energy balance, and ecosystem feedback to climate change; optimizing and validating models on regional and global scales; and understanding responses of ecosystem functions to extreme events. Based on long-term flux observation in individual site, scientists have described the seasonal and inter-annual dynamics, and quantified the baseline rates of ecosystem carbon and water fluxes across different climate and vegetation types. With the development of regional and global flux networks, researchers further understood the spatial patterns of ecosystem carbon and water fluxes and their climatic control mechanisms at regional and global scales. This paper briefly introduces the basic principles, hypothesis and instrument system composition, summarizes the major applications of EC observation on C and water fluxes in terrestrial ecosystems, and finally discusses future directions of EC observation network.

With the development of isotope ratio infrared spectroscopy (IRIS) technology, it is now possible for the in situ high temporal resolution and high precision measurement of carbon isotopic composition (δ ¹³C) and oxygen isotopic composition (δ ¹⁸O) of atmospheric CO₂, which overcomes the low temporal resolution and labor intensive shortcoming of traditional isotope ratio mass spectrometry (IRMS). The dependence of δ ¹³C and δ ¹⁸O on CO₂ concentration (termed as concentration dependence) and the drift due to sensitivity to changing environmental conditions (termed as instrumental drift) are the two main sources of error affecting the IRIS measurements. Therefore, it is important to obtain precise measurements by constructing a proper calibration strategy to solve the concentration dependence and instrumental drift. In this study, we briefly discussed the definition and related theoretical principle of concentration dependence, and elaborated the theoretical and empirical calibration methods of concentration dependence. Moreover, we introduced the calibration methods of instrumental drift, and reviewed the state of the art of calibration methods and its application of IRIS technology. Additionally, we briefly discussed the definition and method of data traceability to the international standard, and reviewed its application of IRIS technology. Finally, we recommend that concentration dependence is corrected by using three standards or above with known CO₂ concentration and its δ ¹³C and δ ¹⁸O, bracketing the CO₂ concentration of samples. The instrumental drift is corrected by setting appropriate calibration frequency and all dataset are traceable to the international standard. In the future, the comparative study of different IRIS instruments and calibration methods should be enhanced, and the similar methods should be used for measuring CH₄, N₂O and H₂O isotopes by IRIS technique. The IRIS technology combined with other technology will provide a new opportunity for ecological research.

Aims Climate warming strongly influences reproductive phenology of plants in alpine and arctic ecosystems. Here we focus on phenological shifts caused by warming in a typical alpine meadow on the Qinghai-Xizang Plateau. Our objective was to explore phenological responses of alpine plant species to experimental warming. Methods Passive warming was achieved using open-top chambers (OTCs). The treatments included control (C), and four levels of warming (T1, T2, T3, T4). We selected Kobresia pygmaea, Potentilla saundersiana, Potentilla cuneata, Stipa purpurea, Festuca coelestis and Youngia simulatrix as the focal species. Plant phenology was scored every 3-5 days in the growing season. The reproductive phenology phases of each species were estimated through fitting the phenological scores to the Richards function. Important findings Under soil water stress caused by warming, most plants in the alpine meadow advanced or delayed their reproductive events. As a result, warming significantly delayed phenological development of K. pygmaea. Warming significantly advanced reproductive phenology of P. saundersiana, S. purpurea and F. coelestis, but not of P. cuneata and Y. simulatrix. In addition, warming significantly shortened the average flowering duration of alpine plant species. The potentially warmer and drier growing seasons under climate change may shift the reproductive phenology of the alpine systems in similar pattern.

Stable isotope technique has been widely used in ecology research with the increasing concern on global change. Our objectives are to better understand the impacts of nitrogen addition and other environment changes on the nitrogen cycling of terrestrial ecosystem, predict the consequent changes in environmental conditions, and provide a reference for policy making to help ensure the sustainable development of terrestrial ecosystems. Based on the relationship between nitrogen (N) isotope composition (δ ¹⁵N) in ecosystem N status and soil N cycle, we summarized the effects and mechanisms of N input and other environment changes on δ ¹⁵N of plant and soil. Most studies show significant positive relationships between N input and δ ¹⁵N values of plant and soil. Higher N input increases soil N availability, which leads to ¹⁵N enrichment in soil because of mass discrimination during soil N cycling processes. Foliar δ ¹⁵N also will be higher as plants take up the relatively ¹⁵N-enriched soil available N. ¹⁵N natural abundance can be a useful tool for assessing nitrogen saturation and N cycling.

Aims There have been many studies of carbon isotope composition (δ¹³C) of C₃ plants in China, and δ¹³C has been widely used as an index of water use efficiency (WUE); however, most studies focused on single sites or small regions. Therefore, our objective was to study the spatial pattern of δ¹³C, the relationships between δ ¹³C and climate factors and whether δ ¹³C can represent WUE in large regions.
Methods We obtained leaf δ ¹³C for 478 C₃ species from 187 sites in China based on the literature.
Important findings The range of δ¹³C was from -33.50‰ to -22.00‰, and the mean was -(27.10‰ ± 1.70)‰. There were significant differences among δ¹³C of grasses, shrubs and trees, with grasses having the highest value and trees the lowest. The result was different from studies in single sites and small regions. For different phylogenic plants, δ ¹³C of seed plants was significantly higher than ferns, the difference between gymnosperms and angiosperms was not statistically significant and monocotyledons had significantly higher values than dicotyledons. Leaf δ ¹³C had irregular variation with increasing longitude, but significantly increased with increasing latitude. Leaf δ ¹³C significantly increased with mean annual temperature and decreasing mean annual precipitation. The relationship between δ ¹³C and precipitation was similar to that of WUE and precipitation, so we conclude that δ ¹³C of C₃ plants can be used as an index of WUE in large regions as well as in single sites or small regions.

Enrichment of atmospheric greenhouse gases resulted from human activities such as fossil fuel burning and deforestation has increased global mean temperature by 0.6 ℃ in the 20th century and is predicted to increase it by 1.4-5.8 ℃ in this century. The unprecedented global warming will have profound long-term impacts on terrestrial plants and ecosystems. Responses of terrestrial plants and ecosystems to global warming may feed back to climate change via ecosystem and global carbon cycling. As one of the major methodology in global change research, ecosystem warming studies can facilitate model projections on potential changes in terrestrial biomes in terms of parameterization and validation. The difficulty in comparing and integrating the results from various ecosystems manipulated with different warming facilities exacerbated the uncertainties of model prediction. In this paper, field facilities in simulating climate warming and their potential applications in different terrestrial biomes were discussed. Critical scientific questions that could be addressed by ecosystem warming studies were proposed.