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The feedback relationship between organisms or ecosystems and environment has been a key issue in ecological research. Manipulative experiments with changing biological or environmental factors and large-scale field experiment networks were regarded as effective approaches to understand and accurately quantify the process and mechanisms underlying ecosystem response and adaptation to environmental changes. In recent years, a few networks have been developed, including large-scale networks of field physics simulation experiment ( i.e ., ECOTRON), ecosystem analysis and experiment platform (AnaEE), international Drought Network, Nutrient Network, and experiment networks based on regional ecological observation stations ( i.e ., USA-ILTER) at global scale. The development of continent-scale experiment network platform is attracting more attention from the academic community, and will play a more important role in understanding the process and mechanism underlying ecosystem responses to environmental change. We reviewed the development of method and experiment system of ecosystem manipulative experiments, and clearly pointed out that different experiments should form a joint collaborative system to answer fundamental scientific questions about the response and adaptation of ecosystem to global environment change. Manipulative experiments could be classified into four types: 1) Physiological and ecological experiments in closed laboratory equipment; 2) semi-open experiments with changing environmental factors in the field; 3) near-natural field experiments; 4) experiment networks based on field ecological station. Furthermore, we discussed the trends in network design of manipulative experiments focusing on ecosystem response and adaptation to environmental changes and the advantages of large-scale experiments based on natural environmental gradients. We put forward a proposal of integrating the technical advantages of different types of experiments and developing a new generation of field experiment network system. The study discussed the research system based on field experiment network, demonstrated the possibility to understand the patterns and mechanisms of the ecosystem short-term response and long-term adaptation to environmental changes, and proposed some equations to quantify the environmental response of ecosystems. The application of the design plan of the manipulative experiments network proposed here will greatly promote the scientific research level of ecosystems and environmental changes in China and even over the whole world, which has important scientific significance for the national response to climate change and ecological environmental construction.

Co-driven by environmental change and human activity, global ecosystem has been experiencing rapid changes, with cascading effects on resources and environment. The changes of ecosystem status and its spatiotemporal evolution drivers, and the related resource and environmental effects have been recognized as the long standing topics of large-scale terrestrial ecosystem science. The coordinated observation networks distributed across different continents and the globe provide the valuable tools for observing and evaluating ecosystem state change, for revealing and elaborating mechanisms underlying ecosystem response, for cognizing and understanding ecosystem evolution, and for predicting and early-warning of ecosystem change. Committing to serving the continental-scale ecosystem science and supporting regional ecological environmental governance, this review first comprehensively analyzed the current status of ecological environment observation research networks, then proposed their development directions. This review advocated to develop a collaborative observation system with characteristics of multi-element, multi-interface, multi-medium, multi-process, multi-scale and multi-method, and to establish the new generation of continental ecosystem observation-experiment research network composed of high technology integration, regional distribution network, network management intellectualization, long-term observation & experiment, multi-functional model simulations, and remote data integration and resource sharing. We elaborated on the function orientation, design philosophy, design scheme, construction objectives and technical system of the research network. We hoped provide references for the development of terrestrial ecosystem observation network in China.

Terrestrial ecosystems are the core components of the biosphere, supporting human life, production and social and economic activities. With the development of human civilization and the progress of science and technology, the continued expanding resources utilization in terms of scale and intensity has caused environmental problems, including global climate change, biodiversity loss, environmental pollution, resource depletion and ecosystem degradation, which threaten the sustainable development of our society. The public expects ecological research providing scientific theories and systematic solutions for the utilization and protection of ecosystems at the continental and global scale, and the maintenance of sustainable development of human society as well. This study aimed to serve the ecological civilization construction in China, ecological security pattern construction, regional ecological and environmental governance, and the development of macrosystem ecology. We reviewed the effectiveness and experience of regional ecological and environmental governance in China, analyzed the scientific requirements and the characteristics of the times of China's eco-civilization construction towards large-scale ecological research, and proposed using a new philosophy, i.e ., nature-based macroecosystem approach, to improve the ecological and environmental governance and ecological security pattern construction at the regional scale. Based on the above-mentioned expounding, we discussed the strategic plan, technical approaches and technological support system of large-scale ecological security pattern construction and ecological and environmental governance in China. This review could provide theoretical references for safe, healthy and beautiful land spatial construction and the progress of eco-civilization of China.

Extreme high temperature is one of important extreme weathers that impact forest ecosystem carbon cycle. In this study, applying CO 2 flux and routine meteorological data measured during 2003-2012, we examined the impacts of extreme high temperature and extreme high temperature event on net carbon uptake of subtropical coniferous plantation in Qianyanzhou. Combining with wavelet analysis, we analyzed environmental controls on net carbon uptake at different temporal scales, when the extreme high temperature and extreme high temperature event happened. The results showed that mean daily cumulative NEE decreased by 51% in the days with daily maximum air temperature range between 35 ℃ and 40 ℃, compared with that in the days with the range between 30 ℃ and 34 ℃. The effects of the extreme high temperature and extreme high temperature event on monthly NEE and annual NEE related to the strength and duration of extreme high tempe-rature event. In 2003, when strong extreme high temperature event happened, the sum of monthly cumulative NEE in July and August was only -11.64 g C·m -2 ·(2 month) -1 . The value decreased by 90%, compared with multi-year average value. At the same time, the relative variation of annual NEE reached -6.7%. In July and August, when the extreme high temperature and extreme high temperature event occurred, air temperature (T a ) and vapor press deficit (VPD) were the dominant controller for the daily variation of NEE. The coherency between NEE T a and NEE VPD was 0.97 and 0.95, respectively. At 8-, 16-, and 32-day periods, T a , VPD, soil water content at 5 cm depth (SWC), and precipitation (P) controlled NEE. The coherency between NEE SWC and NEE P was higher than 0.8 at monthly scale. The results indicated that atmospheric water deficit impacted NEE at short temporal scale, when the extreme high temperature and extreme high temperature event occurred, both of atmospheric water deficit and soil drought stress impacted NEE at long temporal scales in this ecosystem.

Accurate estimation of diffuse radiation is of great significance for evaluating its effect on terrestrial ecosystem carbon exchange. Based on the observed diffuse radiation data in the meteorological observation field in mid-subtropical Qianyanzhou, Jiangxi, China from March 1, 2012 to February 28, 2013, the simulated results of five widely used diffuse radiation decomposition models (Reindl-1, Reindl-2, Reindl-3, Boland, BRL) were validated. The results indicated that, on the 30 min scale, all of the five models could well simulate the diffuse radiation of this area overall. But the effect of models decreased significantly with the rising of clearness index (kt). Especially when kt>0.75, each model was.unable to simulate diffuse radiation in the region. Regarding the simulation of seasonal change of diffuse radiation, the five models could simulate diffuse radiation well in most months. Relative deviation between simulated and observed values of yearly diffuse radiation of five models had a maximum of 7.1% (BRL), a minimum of 0.04% (Reindl-1), and an average of 3.6%. The simulated values of the five models appeared to be overestimated in the summer when radiation was strongest, temperature was highest, and precipitation was relatively low. For example, in July, the diffuse radiation was overestimated by 14.5%-28.2%, 21.2% on average. This was primarily due to the. method of estimating diffuse radiation under the condition of high kt. The uncertainty requires further evaluation in the model application. Considering the results of validation, simulation precision and the accessibility of input variables, the order of the simulation performance of five models was BRL>Reindl-3>Reindl-2>Reindl-1 >Boland.

Global radiation and diffuse radiation were measured from March to June of 2012 in Qianyanzhou Experimental Station of Red Soil and Hilly Land, Chinese Academy of Sciences by ising three types of pyranometers, including CMP11 attached with a shadow ring, SPN1 and RSR3, which were placed in parallel. The observations showed that both global radiation and diffuse radiation measured by these pyranometers had a good linear correlation. The global radiation measured by SPN1 and RSR3 was respectively 3. 0% and 20.5% lower than that measured by the CMP 11. The diffuse radiation measured by SPN1 and RSR3. was respectively 5.5% and 7.9% lower of than that measured by the CMP11. Under the sunny, cloudy and overcast conditions, the daily variations of diffuse radiation measured by the three pyranometers were similar, and hence, the diffuse radiation values at a specific solar elevation angle measured by the different pyranometers were also similar. There was difference in daily accumulative diffuse radiation measured by the different pyranometers. Monthly diffuse fractions of March, April and May were 0.56, 0.59 and 0.70, respectively. In the subtropical area of southern China, the diffuse radiation accounted for a relatively large proportion of the global solar radiation and varied considerably over time. It is necessary to conduct long-term continuous measurements to capture the variability of diffuse radiation over different underlying surfaces.

Forests in Inner Mongolia account for an important part of the forests in China in terms of their large area and high living standing volume. This study reported carbon storage, carbon density, carbon sequestration rate and carbon sequestration potential of forest ecosystems in Inner Mongolia using the biomass carbon data from the related literature. Through analyzing the data of forest inventory and the generalized allometric equations between volume and biomass, previous studies had reported that biomass carbon storage of the forests in Inner Mongolia was about 920 Tg C, which was 12 percent of the national forest carbon storage, the annual average growth rate was about 1.4%, and the average of carbon density was about 43 t · hm(-2). Carbon storage and carbon density showed an increasing trend over time. Coniferous and broad-leaved mixed forest, Pinus sylvestris var. mongolica forest and Betula platyphylla forest had higher carbon sequestration capacities. Carbon storage was reduced due to human activities such as thinning and clear cutting. There were few studies on carbon storage of the forests in Inner Mongolia with focus on the soil, showing that the soil car- bon density increased with the stand age. Study on the carbon sequestration potential of forest ecosystems was still less. Further study was required to examine dynamics of carbon storage in forest ecosystems in Inner Mongolia, i. e., to assess carbon storage in the forest soils together with biomass carbon storage, to compute biomass carbon content of species organs as 45% in the allometric equations, to build more species-specific and site-specific allometric equations including root biomass for different dominant species, and to take into account the effects of climate change on carbon sequestration rate and carbon sequestration potential.

By using eddy covariance technique, this paper quantitatively analyzed the photosynthetic characteristics of tropical seasonal rainforest ecosystem and related environmental controlling factors in Xishuangbanna in 2003-2006. In the study period, less interannual difference was observed in the net photosynthesis of the ecosystem, with the maximum photosynthesis rate (P(eco,opt)), respiration at daytime (R(eco,d)), and apparent quantum yield (alpha) averaged by 0.813 mg x m(-2) x s(-1), 0.238 mg x m(-2) x s(-1), and 0.0023 mg x micromol(-1), respectively. As affected by the interaction of air temperature (Ta) and vapor pressure deficit (VPD), the photosynthetic characteristics had some seasonal differences. In rainy season, the ecosystem had the strongest photosynthetic capacity because of the higher precipitation and warmer air temperature; in foggy and cool season, fog drip played an important role in the water relations of plants, and thereby, the ecosystem photosynthetic capacity was still higher; in dry and hot season, due to the limited precipitation and high temperature, the Ta and VPD increased, inducing a decrease of ecosystem alpha and P(eco,opt). The net CO2 exchange of the ecosystem strongly depended on the Ta above 20 degrees C and the VPD above 1 kPa.

Carbon dioxide (CO2) storage flux in the air space below measurement height of eddy covariance is very important to correctly evaluate net ecosystem exchange of CO2 (NEE) between forest ecosystem and atmosphere. This study analyzed the dynamic variation of CO2 storage flux and its effects on the carbon budget of a temperate broad-leaved Korean pine mixed forest at Changbai Mountains, based on the eddy covariance flux data and the vertical profile of CO2 concentration data. The CO2 storage flux in this forest ecosystem had typical diurnal variation, with the maximum variation appeared during the transition from stable atmospheric layer to unstable atmospheric layer. The CO2 storage flux calculated by the change in CO2 concentration throughout a vertical profile was not significantly different from that calculated by the change in CO2 concentration at the measurement height of eddy covariance. The NEE of this forest ecosystem was underestimated by 25% and 19% at night and at daytime, respectively, without calculating the CO2 storage flux at half-hour scale, and was underestimated by 10% and 25% at daily scale and annual scale, respectively. Without calculating the CO2 storage flux in this forest ecosystem, the parameters of Michaelis-Menten equation and Lloyd-Taylor equation were underestimated, and the ecosystem apparent quantum yield (alpha) and the ecosystem respiration rate (Rref) at the reference temperature were mostly affected. The gross primary productivity (GPP) and ecosystem respiration (Re) of this forest ecosystem were underestimated about 20% without calculating the CO2 storage flux at half-hour, daily scale, and annual scale.