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It is important to quantitatively analyze the effects of protection of important ecological spaces in China to ensure national ecological security. By considering changes in the ecological land, this study examines the effects of protecting three types of important natural ecological spaces in China from 1980 to 2018. Moreover, considering important ecological spaces and their surroundings yields differences in the effects of protection between internal and external spaces, where this can provide a scientific basis for the categorization and zoning of China’s land. The results show the following: (1) In 2018, the ratio of ecological land to important natural ecological spaces accounted for 92.64%. This land had a good ecological background that reflects the developmental orientation of important ecological spaces. (2) From 1980 to 2018, the area of ecological land in important ecological spaces shrank but the rate of reduction was lower than the national average, which shows the positive effect of regulating construction in natural ecological spaces. The restorative effects of ecological projects to convert farmland into forests and grasslands have been prominent. The expanded ecological land is mainly distributed in areas where such projects have been implemented, and the reduced area is concentrated in grain-producing areas of the Northeast China Plain and agricultural oases of Xinjiang. In the future, the government should focus on strengthening the management and control of these areas. (3) The area ratio of ecological land was the highest in national nature reserves. The rate of reduction in its area was the lowest and the trend of reduction was the smallest in national nature reserves, which reflects differences in the status of ecological protection among different spaces. (4) The ratio of ecological land to important ecological spaces was higher than that in the surrounding external space, and the rate of reduction in it was lower. Thus, the effects of internal and external protection had clear differences in terms of gradient.

Due to the fragmentation of protected areas (PA), it is important to build ecological corridors in order to connect scattered PA and form protection networks for biodiversity conservation. We take the Chinese ecological conservation redline (ECR) as an example to study the construction of ecological corridors. China has defined ECR to improve the system of PA in key ecological functional zones, nature reserves, and areas of sensitive and fragile ecological environment. In this study, 187 core areas of ECR were identified using ArcGIS masking and dissolving technology to build corridors, covering 95% of the total ECR areas. Using the Linkage Mapper tool and the Pinchpoint Mapper, we identified 454 ecological corridors 68,794 km long. The results of the line density analysis showed that there are 9 key regional biological corridors connected to the ECR at the national scale, which must focus on protecting and strengthening ecological construction during the implementation of ecological conservation redline policy. Our study will provide references for developing a regional pattern of ecological security, territorial spatial planning, and will promote the implementation of biodiversity conservation policies.

The large tectonic lake is one of the most important water bodies in the source area of the Yellow River (SAYR), northeastern Qinghai-Tibet Plateau (QTP). It plays a key role in decelerating climatic change and regulating regional climate patterns. In this study, we used Landsat images (MSS, TM, ETM+ and OLI) of Lake Gyaring and Lake Ngoring (the Two Sisters Lakes), which are the two largest tectonic lakes in the SAYR, to determine annual lake area fluctuations from 1986 to 2020. The results show that lake area increases were generally consistent with a warming trend in the SAYR. The temperature signals were separated from the lake area changes by using a detrending analysis and found that the processed data are closely correlated with variations of precipitation and streamflow in the SAYR, and the previously reported paleoclimate records, which include the δ18O record from stalagmite, A/C (Artemisia/Chenopodiaceae) ratio from lake sediment and scPDSI (self-calibrating Palmer Drought Severity Index) from the tree ring on the northeastern margin of the QTP. The phase of relatively large lake areas typically coincides with a negative excursion in δ18O, a high A/C ratio, and elevated scPDSI values, while the opposite is true for smaller lake areas. It is suggested that the total area of the Two Sisters Lakes is closely associated with hydroclimatic conditions in the SAYR. Furthermore, an association of high TSI anomalies with the water area expansion of the Two Sisters Lakes is also observed, implying that solar activity is the key driving factor for the hydrologic variability in the SAYR on decadal timescales. The findings of our study highlight the validity of previous paleoclimate archives in the northeastern QTP and demonstrate the potential of using remote sensing techniques to investigate paleoclimate.

In the quantification model of emission intensity of emission sources, the estimation of the background concentration of greenhouse gases near an emission source is an important problem. The traditional method of estimating the background concentration of greenhouse gases through statistical information often results in a certain deviation. In order to solve this problem, we propose an adaptive estimation method of CO2 background concentrations near emission sources in this work, which takes full advantage of robust local regression and a Gaussian mixture model to achieve accurate estimations of greenhouse gas background concentrations. It is proved by experiments that when the measurement error is 0.2 ppm, the background concentration estimation error is only 0.08 mg/m3, and even when the measurement error is 1.2 ppm, the background concentration estimation error is less than 0.4 mg/m3. The CO2 concentration measurement data all show a good background concentration assessment effect, and the accuracy of top-down carbon emission quantification based on actual measurements should be effectively improved in the future.

Biomass seedling containers were prepared from agricultural field wastes (i.e., rice straw and corn stalk) and cow manure, mixed with a starch adhesive. Based on the ratio of raw materials, different models of seedling containers were designed and tested. The performance of the seedling containers was characterized by measuring their forming ability in the mold, water absorption, air permeability, density, and various physical and chemical properties. The results showed that the percentage of well-shaped containers formed in the mold could reach as high as 98% when the ratio of rice straw to cow dung was 1:15, and the moisture content of the containers was approximately 15%. As the straw or stalk content increased, the percentage of seedling containers having good shape and compactness decreased, whereas the air permeability and water retention values increased. At the same mixture ratio, rice straw seedling containers were better than corn stalk seedling containers. The nutrient content of the seedling containers was over 10 times that of the soil surrounding the container, which could contribute to the conservation of soil fertility, as well as the seeding and transplanting of species in the process of ecological restoration.

The Qinghai-Tibetan Plateau (QTP) is one of the most difficult eco-regions for revegetation on degraded grassland because of its harsh environment. Micro-topography could affect habitat conditions important to ecological restoration on sandy land; however, the interaction between revegetation and micro-topography has been rarely reported on sand dunes of the QTP. Here, we quantified vegetation (including coverage, leaf area index (LAI), height, and crown diameter) and micro-topographic parameters (including elevation, slope, and aspect) to assess the effects of topography on revegetation using field observation data during 2008–2017 and terrestrial laser scanning (TLS) in 2017. The results showed that: 1) the tested plant species for revegetation has changed significantly from 2008 to 2017, and the current dominant plant species were mainly introduced from north China, including Hedysarum scoparium, H. fruticosum, and Artemisia sphaerocephala. 2) The effectiveness of revegetation has been improved remarkably over the past ten years. The vegetation coverage varies from 68.4% to 80.5% at four big quadrats of 20 m × 20 m, while the LAI value varies from 2.30 to 3.27, the shrub height ranges from 1.12 m to 7.57 m, and the crown diameter ranges from 0.24 m to 6.96 m. 3) A total of 153 shrubs were extracted in these four quadrats using TLS; and 56.9%, 21.6% and 10.5% of them are distributed on the southeastern, southern, and eastern aspects, respectively. The height and crown diameter of individual shrubs are significantly correlated with the local slope (p

To reveal the characteristics of climate change and the controlling factors for vegetation dynamics in the Ordos, Inner Mongolia, China, 34 years (1982–2015) of regional climate variables and vegetation dynamics were investigated. The results show that: Annual mean air temperature (TMP) significantly increased with a linear slope of 0.473°C/10yr. Annual precipitation (PRE) had a non-significant positive trend nearly 5 times lower than the trend of potential evapotranspiration (PET). The average Normalized Difference Vegetation Index (NDVI) computed for the region was found to show a significant positive trend (6.131×10−4/yr). However, all climate variables displayed non-significant correlations with NDVI at annual scale. The reduction of desert and the increase of grassland over the past decades were accountable for the increased NDVI. Principal components analysis revealed that the regional climate change can be characterized as changes in temperature, humidity and the availability of radiant energy. Based on principal components regression coefficients, NDVI was mostly sensitive to humidity component, followed by growing season warmth (WMI). Spatially, 93.1% of the pixels displayed positive trend and 61.8% of the pixels displayed significant change over the past decades. Both principal regression analysis and partial correlation analysis revealed that NDVI in eastern part of Ordos was sensitive to TMP, whereas, NDVI in southern and western areas of Ordos displayed the high sensitivity to combined effects of PRE and cloud coverage (CLD). Partial correlation analyses also revealed that TMX was a surrogate for aridity, TMN was a representative of humidity, and temperature variations below the threshold of 5°C (CDI) were less important than WMI. We conclude that regional climate change can be characterized by warming and increased aridity. The significant positive trend of regional NDVI and the non-significant correlations between NDVI and climate variables at annual scale suggests the hidden role of the human activities.

Climate change and human activities are two dominating factors affecting soil moisture temporal variation trends, whereas their individual contributions to soil moisture trends still remain uncertain in the karst areas of Southwest China. Based on the linear regression trend analysis, Mann–Kendall mutation detection, and residual analysis methods, we quantified the contributions of climate change and human activities to soil moisture temporal variation trends in the karst areas of Southwest China. The results showed that the soil moisture in the study area experienced a drying trend from 1982 to 2015. The mutated year was 1999, and the soil moisture decreasing trend was more evident from 2000 to 2015 than from 1982 to 1999. Human activities and climate change accounted for 59% and 41%, respectively, of soil moisture drying trends. Owing to the spatial heterogeneity of geomorphic features, the individual contributions of climate change and human activities to soil moisture trends exhibited regional differences. Although remarkable regional vegetation restoration was found since applying the Grain for Green Project, the negative impact of vegetation restoration on soil moisture cannot be neglected. This study is a quantitative analysis of the relative impacts of climate change and human activities on soil moisture trends, and our findings provide a theoretical reference for the sustainable use of soil water resources in the karst areas of Southwest China.

River discharge is crucial to water resources development and ecological protection. However, in some arid areas of northwest China, it is still difficult to measure discharge accurately. In this study, unmanned aerial vehicle (UAV) imagery has been used to estimate river discharge at two river sections in the upper reaches of the Shiyang River in the eastern part of the Qilian Mountains based on the Manning formula. The estimated discharges at those two sections are 1.16 m3/s and 3.11 m3/s, respectively. Taking the discharges measured by an acoustic Doppler current profiler (ADCP) as the reference, the relative error of the estimates is below 5%, which is accurate enough for water resources management in mountain basin regions. Multiple high-resolution satellite images were also used to calculate water discharges at the two sections, which were in good agreement with the discharges estimated from UAVs. This study demonstrates the feasibility of using UAVs to estimate river discharge, which is of great significance for future regional-scale water resource assessments.

In the 70 years since the founding of the People’s Republic of China, nature reserves have increased in both quantity and variety and the focus of China’s nature conservation efforts has shifted from the construction of protected areas to the development of a regional ecological security pattern. China’s nature conservation efforts have been continuously strengthened, leading to remarkable results. In 1956, China built its first nature reserve—Dinghushan Nature Reserve. After more than 60 years, China’s nature conservation system has gradually matured. The nature conservation system consists of geological parks, natural and cultural heritage sites, wetland parks, aquatic germplasm reserves, marine protected areas, and specially protected islands. On this basis, China successively added ecological function areas (2008), ecologically fragile areas (2008), key ecological function areas (2011) and other key ecological conservation areas to the system. In 2011, China first put forward the proposal of “delineating the ecological conservation red line.” In 2015, China launched a pilot reform of its national park system and started building a nature conservation system in which national parks played a major role. These two major measures further enriched China’s nature conservation system and significantly accelerated the formation of a sound national ecological security pattern.

Massive grasslands on the Qinghai-Tibetan Plateau(QTP) provide vital ecosystems services, which have been decreased by land degradation associated with global change. Effective efforts and actions of restoration and management are required to promote the sustainable development of these grassland ecosystems with global importance. This special issue collected numerous papers to address share the innovative theoretical foundations and practical approaches for restoring and protecting QTP’s grassland ecosystems in the era of global change. The findings from the collected papers of this special issue stated that the ecosystems services of the QTP’s grasslands are declining due to weakened interfaces among soil, plant and grazing animals in the QTP’s grassland ecosystems by climate and land use changes. Applicable actions such as climate change mitigation and adaptation, close-to-nature restoration, rotational grazing regime with moderate grazing intensity should be taken to enhance the ecosystem services through rebuilding rational soil-plant-animal interfaces.

With the integration of regional development, regional ecological environment problems are becoming more and more severe, which has attracted extensive attention of researchers. Therefore, the 589th XiangShan Science Conference was organized to discuss how to build the regional ecology disciplinary system, and how to solve the current outstanding regional environment problems. It was agreed that regional ecological protection theory has characteristics of the current times and practical value, and the construction of regional ecological discipline is imperative. Based on the features of regional ecological problems, this paper puts forward three core theories of regional ecological protection. Firstly, the theory of “the dual coupling of ecological donor-ecological receptor”, which refers to the dual relationship of the land-land coupling and human-land coupling, are based on the ecological donor and the ecological acceptor. Land-land coupling indicates the coupling of ecological donor and receptor on space in the ecological domain, and the interdependence level between the donor and receptor determines healthy development and the ecological integrity of the ecological domain; human-land coupling refers to the coupling of the economic social system and natural ecological system in the ecological domain, and the suitability of human living environment and industries determines the degree of human-land coupling in the ecological-economic system. The second theory is the “triune theory of ecological pattern-process-function”. It was argued that the pattern is the carrier of the process, and the change of pattern leads to the change of ecological process. Process is the motivation and the driving force in forming pattern, and pattern will also respond to the change of process. The interaction of ecological pattern and process will show different ecological functions. Therefore, they are mutually affected and are reciprocal causation for each other. The regional coordinated development and ecological security can only be realized by integrated pattern, continuous process and matching function between the ecological donor and receptor. The third theory is “the suitable relationship between ecological biological capacity and regional development”, which is based on the suitability among human settlements, industrial structure, distribution, scale and natural resources & environment. Therefore, the maintenance and improvement of the ecological carrying capacity has direct effect on the sustainable development of the whole ecological domain. The economic and social development in the ecological domain must be appropriate with its ecological carrying capacity in order to realize the coordination of human-land system. From the view of the interaction among the ecological donors, ecological receptors, and ecological medium in the ecological domain, regional ecology analyzes ecological pattern, process and function in the ecological domain, and emphasizes the coupling of ecological carrying capacity as well as natural, economic and social factors. Three core-theory system is the fundamental solution to solve the land-land and human-land coordination problems, and the research results will play an important role in guiding the construction of regional ecological security pattern and space optimization, regional ecological protection and improvement of ecological service function, protection and repair technologies of regional ecological governance, as well as the optimization of regional industrial structure and distribution, etc. This theory provides new epistemology and methodology for solving current regional environmental problems.

In response to drastic land use changes and inefficient management, in 2015 the Chinese government launched a strategic project entitled the Delineation and Defense of Ecological Protection Red Lines (EPRLs). The purpose of EPRLs was to integrate all conservation areas into a system of unified and strict management. This report introduces the background, content, and management policies of the EPRLs system. EPRLs are either those natural spaces with the greatest importance or the most vulnerability and sensitivity, and they are the minimum area needed for the maintenance of national ecological security. The Guidance for Delineation of EPRLs identified the scope of development prohibited zones and other areas under protection, and assessed areas with important ecological functions, vulnerability or sensitivity. Provincial governments are currently carrying out the delineation of EPRLs and will eventually issue and execute the scheme of EPRLs, while the central government is drafting a complete set of management policies including permitted industrial activity, monitoring and regulation, and ecological compensation.

The expansion of artificial constructs with the rapid economic development in China has led to ecological and environmental emergencies. The extent of the decline in natural resources and environmental conditions has recently been recognized. Identifying “ecological protection redlines”, i.e. ecological limits, to guarantee ecological baselines for natural resources and ecosystem service functions would therefore help to coordinate economic development and to protect ecological resources in the coming years. We used remotely sensed and climatic data to delimit the ecological protection redlines for Zibo, a typical and important city in Shandong province, as an example to illustrate the principles and methodology of ecological protection redlines. The area of the ecological protection redlines for Zibo encompassed 1132.26 km 2 , accounting for 18.98% of the total area of Zibo, were mainly distributed in the southern regions of the municipality, and consisted of extremely important areas of ecosystem service functions, including water conservation, both soil and water conservation, windbreaks and sand fixation, and the conservation of biodiversity. This area is extremely sensitive, and development is forbidden. Strict measures of management and control should be implemented to protect the long-term effectiveness of ecological protection redlines.

Other nations could learn from China’s red-line initiative to preserve nature, biodiversity and ecosystem services in the country, says Jixi Gao. Other nations could learn from China’s red-line initiative to preserve nature, biodiversity and ecosystem services in the country, says Jixi Gao.

Understanding rainfall anomalies and their relationship with floods in the Yangtze River Basin (YRB) is essential for evaluating flood disasters, which have a great impact on the development of agriculture and the economy. On the basis of daily rainfall data from 1961 to 2010 from 178 meteorological stations, the temporal and spatial characteristics of rainfall anomalies in the YRB were studied on an annual scale, seasonal scale, and monthly scale. The annual rainfall of the YRB showed a generally increasing trend from 1961 to 2010 (14.22 mm/10 a). By means of the Bernaola–Galvan abrupt change test and Redfit spectrum analysis, it was found that the annual average rainfall increased abruptly after 1979 and had a cycle of 2–3 years. On the seasonal scale, the rainfall in spring and autumn showed a gradually decreasing trend, especially in September, while it showed a significant increasing trend in summer and winter in the YRB. As for the monthly scale, the rainfall in the rainy season from June to July presented a clear increasing trend during the study period, which greatly enhanced the probability of floods in the YRB. Additionally, through the analysis of the spatial distribution characteristics of rainfall in the entire YRB from 1961 to 2010, it was observed that the annual rainfall amount in the YRB presented an “increase–decrease–increase” tendency from east to west, accompanied by a rain belt that continuously moved from west to east. Moreover, the rainfall characteristics in flood years were summarized, and the results revealed that the years with rainfall anomalies were more likely to have flood disasters. However, anomalies alone would not result in big floods, the spatially and temporally inhomogeneous rainfall distribution might be the primary reason for flood disasters in the entire YRB.

Experiments were conducted in a dynamic chamber system to measure the formation of secondary organic aerosol (SOA) and particle-bound reactive oxygen species (ROS) produced from limonene ozonolysis in the presence of NO by varying the ratio of O_3 to NO. A diffusion cell system was used to produce the constant input of limonene in to the chamber, and six sets of experiments were conducted. The concentration of SOA mass and ROS produced were measured at steady-state. ROS, including peroxides, peroxy radicals and ions, was determined using dichlorofluorescin (DCFH) and converted to equivalent H_2O_2 concentration. The particle mass was measured using a tapered element oscillating microbalance (TEOM) and a scanning mobility particle sizer (SMPS) was used to obtain particle volume distributions. The results showed that the SOA mass concentration ranged from 30.3 to 157.3 μg m^(-3), and the ROS concentration ranged from 6.1 to 29.4 nmol m^(-3) of H_2O_2. For the different combinations of NO_x and O_3, the concentration ratio of [O_3]/[NO] around 1 was found to produce highest SOA mass and ROS, which is 157.3 μg m^(-3) and 29.4 nmol m^(-3). The SOA density was estimated by comparing the mass concentrations with the volume concentrations ranged from 1.21 to 1.48 g cm^(-3). The highest SOA density (1.48 g cm^(-3)) occurred with the lowest concentration ratio of [O_3]/[NO]. Compared with other monoterpene and linalool where each has one unsaturated carbon bond in other studies, limonene which has two unsaturated carbon bonds. Thus, it is the most efficient in generating the SOA and ROS concentrations in prior experiments without NO present.

The change of freeze-thaw pattern of the Tibetan Plateau under climate warming is bound to have a profound impact on the soil process of alpine grassland ecosystem; however, the research on the impact of the freeze-thaw action on nitrogen processes of the alpine grassland ecosystem on the Tibetan Plateau has not yet attracted much attention. In this study, the impact of the freezing strength on the soil nitrogen components of alpine grassland on the Tibetan Plateau was studied through laboratory freeze-thaw simulation experiments. The 0–10 cm topsoil was collected from the alpine marsh meadow and alpine meadow in the permafrost region of Beilu River. In the experiment, the soil samples were cultivated at–10°C,–7°C,–5°C,–3°C and–1°C, respectively for three days and then thawed at 2°C for one day. The results showed that after the freeze-thaw process, the soil microbial biomass nitrogen significantly decreased while the dissolved organic nitrogen and inorganic nitrogen significantly increased. When the freezing temperature was below–7°C, there was no significant difference between the content of nitrogen components, which implied a change of each nitrogen component might have a response threshold toward the freezing temperature. As the freeze-thaw process can lead to the risk of nitrogen loss in the alpine grassland ecosystem, more attention should be paid to the response of the soil nitrogen cycle of alpine grasslands on the Tibetan Plateau to the freeze-thaw process.

Climate change and land use management were competing explanations for vegetation dynamics in cold and semi-arid region of north-eastern Inner Mongolia, China. In order to reveal the role of human disturbance and clarify the regional climate-vegetation relationship, long-term (1982–2013) datasets of climate variables and vegetation dynamics in a forest-steppe transition zone of north-eastern Inner Mongolia, China were collected. Partial correlation analyses, principal components regression (PCR), and residual analyses were conducted to reveal the vegetation sensitivities to different climate variables and the impact of anthropogenic activities on climate-vegetation relationship. The results showed that. (1) Annual mean air temperature (TMP) significantly increased at a linear slope of 0.08 °C per decade, annual precipitation (PRE) had an insignificantly linear slope of −16.42 mm per decade (p = 0.15). The average Normalized Difference Vegetation Index (NDVI) had a significantly negative trend over the past decades. A change point around the year 1998, coincided with the occurrence of an intense global El Nino event was also identified. (2) Regional climate change can be represented by changes in temperature, humidity and radiation. NDVI in the steppes display high sensitivity to moisture availability. Whereas, forests was influenced by the warmth index (WMI), accumulation of monthly temperature above a threshold of 5 °C. Partial correlation analyses showed that pixels of positive correlation with PRE (controlling TMP) overlap with the pixels of high partial correlation with minimum temperature (controlling maximum temperature), which suggests a hidden link between minimum temperature and PRE in this region. (3) The spatial distribution of significantly decreased NDVI overlap with cropland expansion, as well as the low residual square (R2) from PCR analysis. The NDVI decline in these expanded croplands suggests human disturbance on vegetation dynamics. Following climate warming, NDVI of forested land displayed positive trend. Whereas, most of steppe displayed negative trend, possibly resulting from combined effects of climate drying and human disturbance. We conclude that the regional climate change can be characterized as warming and drying. Steppe areas were sensitive to humidity changes while forested land was mostly influenced by growing season warmth. Overall, the regional NDVI displayed significantly negative trend over the past decades. Beyond climate drying, cropland expansion in the transition area between grassland and forested land is also an important driver for decreased NDVI. Further studies on the ecological and hydrological consequences of crop land expansion is necessary.

The expansion of protected area (PA) networks is necessary for countries and territories worldwide to conserve biodiversity, protect natural ecosystems and achieve sustainable development. However, challenges remain in expanding the PA network effectively, especially in regard to addressing priority conservation areas and balancing social development and ecological conservation. These problems are addressed in the “Ecological Conservation Redline” (ECR), an ambitious program launched in China to establish a comprehensive and large-scale conservation network. In this study, we presented a framework based on the ECR to guide PA network expansion, which identifies the areas requiring priority conservation and incorporates coordinated ecological conservation and social development. The framework consists of three steps: (1) design the network by identifying the hotspots of ecological function, ecological fragility and biodiversity, (2) transform the network from theory to practice through boundary verification, and (3) define a management policy with consideration of the livelihood of local communities. This framework was applied in Sichuan Province, China to demonstrate its effectiveness on expanding the PA network and improving conservation efforts. The framework provides important references for planning of PA networks and contributes to global expectations of effective environmental management.

Long-term (1982–2013) datasets of climate variables and Normalized Difference Vegetation Index (NDVI) were collected from Climate Research Union (CRU) and GIMMS NDVI3g. By setting the NDVI values below the threshold of 0.2 as 0, NDVI_0.2 was created to eliminate the noise caused by changes of surface albedo during non-growing period. TimeSat was employed to estimate the growing season length (GSL) from the seasonal variation of NDVI. Statistical analyses were conducted to reveal the mechanisms of climate-vegetation interactions in the cold and semi-arid Upper Amur River Basin of Northeast Asia. The results showed that the regional climate change can be summarized as warming and drying. Annual mean air temperature (T) increased at a rate of 0.13 °C per decade. Annual precipitation (P) declined at a rate of 18.22 mm per decade. NDVI had an insignificantly negative trend, whereas, NDVI_0.2 displayed a significantly positive trend (MK test, p

China proposed the Ecological Conservation Redline (ECR) strategy in 2011 and listed it as an important part of the ecological promotion process in 2013. In 2017, China implemented the designation of ECR at a national scale. The aim was to demarcate areas with unique ecological functions. Therefore, the ECR became a key part of national ecological security. Three major types of area are covered by the ECR so that important ecosystem functions can be protected. These are ecologically fragile zones, biodiversity, and natural landscapes. The ECR is characterized as being fundamental, systematic, and mandatory. This study summarizes the developmental background, theoretical framework, and structural composition of ECR, and highlights recent advances. A comparison of the ECR to international protected areas showed that they were generally similar, but there were differences in the methods used to protect targets, their system design, and their management, which provided insights and recommendations that could improve the construction and management of protected areas in the future. These included: (1) increasing the integrity of ecological protection by replacing dispersed protection with a more comprehensive and systematic approach, (2) increasing the spatial accuracy of protection to enhance the effectiveness of protection, and (3) implementing an overall-process management to guarantee the sustainability of protection. Finally, suggestions are made for further protected area improvements and ecological protection, including further theoretical exploration, strengthening management, and facilitating international cooperation.

The effects of degradation of alpine wetland meadow on soil respiration (Rs) and the sensitivity of Rs to temperature (Q10) were measured in the Napa Lake region of Shangri-La on the southeastern edge of the Qinghai-Tibet Plateau. Rs was measured for 24 h during each of three different stages of the growing season on four different degraded levels. The results showed: (1) peak Rs occurred at around 5:00 p.m., regardless of the degree of degradation and growing season stage, with the maximum Rs reaching 10.05 μmol·m−2·s−1 in non-degraded meadows rather than other meadows; (2) the daily mean Rs value was 7.14–7.86 μmol·m−2·s−1 during the mid growing season in non-degraded meadows, and declined by 48.4–62.6% when degradation increased to the severely degraded level; (3) Q10 ranged from 7.1–11.3 in non-degraded meadows during the mid growing season, 5.5–8.0 and 6.2–8.2 during the early and late growing seasons, respectively, and show a decline of about 50% from the non-degraded meadows to severely degraded meadows; (4) Rs was correlated significantly with soil temperature at a depth of 0–5 cm (p 10 and Rs (p 10. The results suggest that vegetation degradation impact both Rs and Q10 significantly. Also, we speculated that Q10 of alpine wetland meadow is probable greater at the boundary region than inner region of the Qinghai-Tibet Plateau, and shoule be a more sensitive indicator in the studying of climate change in this zone.

China has experienced unprecedented economic development in recent years and is now facing severe challenges caused by the over-consumption of resources and by ecological and environmental degradation. To assess the influence of resource exploitation and ecological trade, we have developed an index of excessive resource consumption based on the concepts of ecological deficit and ecological over-shoot, and we have used the ecological trade deficit to assess the pressure created by the export and import of resources and products. Our analysis indicated that China's consumption footprint surpassed its biocapacity in 1983, leading to an ecological deficit, and the production footprint surpassed its biocapacity in 1986, leading to an ecological over-shoot, as the over-consumption of natural resources grew. By 2010, 3.6 times the current area of bioproductive land was needed to provide sufficient resources to meet the consumption. China has been encouraging the development of exporting enterprises by implementing a series of financial and tax incentives, which have stimulated the economy in the short-term but have gradually increased the ecological trade deficit since 2000.

Spatial and temporal distributions of temperature, precipitation and wind speed from 1960 to 2013 at 179 meteorological stations situated in the desertification prone region (DPR) of China are analysed using the Mann–Kendall test and the Theil–Sen's slope estimator on monthly, seasonal and annual timescales. The results indicate that annual mean temperature has increased at a rate of 0.33 °C (10 year)−1 over the DPR. Tmin generally increased at a higher rate than Tmax in the majority of the months and seasons over the past 54 years; this has resulted in a decrease in the diurnal temperature range. Precipitation increased for the majority of the meteorological stations in the western area of the DPR, and decreased in the eastern area, but few of these trends are statistically significant on all timescales. The majority of meteorological stations recorded a significant decrease in wind speed at the majority of timescales. Results from this investigation show that the climate is becoming warmer and wetter in the western area of the DPR, and warmer and drier in eastern area of the DPR. A greater understanding of how the historical climate has been changing enables scientific support for the adaption of mitigation policies for land desertification/degradation, water resources, ecological projects and agricultural production. These policies will aid in combating the desertification processes, maintaining ecological security and promoting sustainable development in the DPR.

The dry anaerobic co-digestion of LW (livestock waste), OFHW (organic fraction of household waste), and AR (agricultural residue) was evaluated in terms of pH stability, organic removal rate, and methane yield. The total quantity of the solids involved in the digestion was adjusted to 25%. All the reactors were inoculated by 20% (in dry weight) of the municipal sludge. The dynamic changes in the pH values of the LW-AR-OFHW mixture co-digestions underwent four stages and differed from those of wet anaerobic digestion. The decrease in VS (volatile solids), volume, and weight of the LW-AR-OFHW mixtures was higher than those in AR and OFHW. The VS, volume, and weight reductions in LW-AR-OFHW co-digestion were 54.7%, 82.2%, and 72.7%, respectively. However, the VS, volume, and weight reductions in AR were only 11.1%, 20.5%, and 19.8%, respectively, and those in OFHW were only 27.4%, 45.0%, and 40.9%, respectively. The LW-AR-OFHW mixture co-digestions enhanced the methane production of the co-digester (256 m 3 /ton VS), whereas AR and OFHW produced only 12 and 93 m 3 methane/ton VS, respectively.

We propose an eco-service provision unit method for estimating the benefit and spatial differences of forests in controlling soil erosion. A total of 197 eco-service provision units were grouped on 1424.43 km2 of forest according to differences in vegetation, slope, soil, and rainfall. The amount of soil conservation and its economic value were estimated. The forests in Anji County prevent 4.08 × 105 tons of soil from eroding annually, thereby avoiding 1.36 × 104 tons of nutrient loss (on-site cost) and preventing 149 tons of nutritive elements from entering water systems (off-site cost). From an economic perspective, the soil nutrient conservation in the forests of Anji County generated an annual benefit of 43.37 million RMB (Chinese Currency, 6.20 RMB = US$1). On average, each hectare of ecological forest contributed up to 436 RMB annually because of soil conservation. Ecological complexes with higher rainfall intensity, such as broadleaf forest and red soil on slope gradients >25°, contributed the highest soil conservation benefits. This study identified and quantified the dominant contributors and magnitudes of soil conservation provided by forests. This information can benefit decision making regarding differentiated ecological compensation policies.

In the water-limited Beijing–Tianjin Sand Source Control Project Region, reference evapotranspiration (ETO) is a vital hydrological factor for the revegetation implementation, and its long-term variation is of much interest in climate change studies. In our study, temporal and spatial patterns in ETO and related driving factors in the project region are evaluated for the period 1959–2011, based on daily data from 46 meteorological stations, using Mann–Kendall (M-K) test, Sen's slope estimator, and multivariate regression. The results indicated that annual ETO had an insignificant decreasing trend in the study area, in which 15 stations showed significant negative trends and only 1 station showed significant positive trend at the 95% confidence level. Significant downward ETO was detected in the north sub-region (I) in spring, in the west sub-region (II) in summer and autumn. Analysis of the impacts of meteorological variables on spatiotemporal trends of ETO showed that wind speed was the most dominant factor affecting ETO variation at 35 stations. Downward ETO induced by decreased wind speed may be result from revegetation of Beijing–Tianjin Sand Source Control Project. In addition, ETO change was influenced by sunshine duration in summer and maximum air temperature in winter. Better understanding ETO response to climate change will enable efficient use of water resources and vegetation management, which could improve the ecological and environmental quality in Beijing, Tianjin, and the surrounding areas.

Water transparency represented by the Secchi disk depth (Zsd) plays an important role in understanding water ecology environment variations, especially for optically complex and shallow lake waters. In this study, using in situ measured remote sensing reflectance (Rrs), diffuse attenuation coefficient (Kd), and Zsd data collected in Lake Taihu (China), a regional algorithm for estimating Kd from Rrs was designed, and the semi-analytical model proposed by Lee et al. (2015) (hereafter called Lee_2015 model) was refined using a linear scaling correction for remote sensing of Zsd. The results showed that a good agreement between the derived Kd and in situ measured data (mean absolute percentage error (MAPE) = 26% for Kd(490); MAPE < 5% for Kd at 443, 555, and 660 nm). The in situ Rrs-derived Zsd results using the refined Lee_2015 model compared well with the in situ measured Zsd (R2 = 0.72 and MAPE = 36%), which was an obvious improvement over the Lee_2015 model in our study region. Subsequently, the refined Lee_2015 model was applied to the geostationary ocean color imager (GOCI) observations between 2012 and 2018 to yield the spatial and temporal variations of water transparency in the Lake Taihu waters. The long-term mean distribution of Zsd revealed that water transparency values in the northeastern Lake Taihu were generally higher than those in the southwest part. Monthly climatological Zsd patterns suggested that the Zsd distributions had large temporal variability, and distinct monthly patterns of Zsd existed in different subregions of Lake Taihu. The significant interannual variations of Zsd in Lake Taihu are probably affected by a combination of the water column stability mainly caused by wind, water temperature, human activity, and riverine discharge. The present study can provide a new approach for quantifying water visibility and serve for water-color remote sensing of optically complex and highly turbid waters.

The grassland ecosystems cover above 60% of Qinghai-Tibetan Plateau (QTP) and provide important ecosystem services and functions at local and regional scales. However, both anthropogenic and non-anthropogenic disturbances are challenging the sustainability of the QTP’s grassland ecosystems in the era of global change. In this review paper, we summarized the causes and effects of grassland degradation, restoration practices used on degraded grasslands, impacts of climate change and nitrogen deposition on plants and soils, adaptation strategies to climate changes, impacts of livestock grazing on plants and soils, and sustainable grazing management on the QTP. We believed that the integration of internal drivers of ecosystem fragility with external disturbances such as overgrazing are the major causes of grassland degradations on the QTP. The quantitative evaluation systems for grassland ecosystem health including plant, soil and livestock indicators are theoretically feasible and technically reliable. The major impacts of grassland degradation on the QTP are loss of biodiversity, increased water erosion, reduced carbon sequestration, decrease pastoral productivity and reduced local human well-being. The current restoration practices are mostly revegetation of “Bare Land” severely degraded grasslands using cultivated grasses. Other restoration practices such as grazing fallow and grassland fencing can be applied to restore the lightly or moderately degraded grasslands. We believed that the side effects from soil drying on plant productivity and diversity in manipulative warming experiments could be the main cause of controversial findings about the effects of climate change on plant productivity, diversity, phenology, soil physics, biochemistry and organisms. Many scholars argued the advances and delays in greening-up date, lengthening and shortening of the growth period in the phenological responses of alpine grassland plants to a warming climate. Multiple sources of remote sensing data and diverse interpretive approaches should be applied and ground-based observations and surveys should be performed to improve the accuracy and reliability of model predictions on plant phenology. Inconsistent conclusions of climate change impacts on soil biochemistry and organisms except soil acidification and eutrophication have been widely observed in most manipulated studies of nitrogen deposition. Adaptive strategies should be employed to promote grassland system’s sustainability of the QTP. Rotational grazing regime with moderate grazing intensity in the warm season may retain or promote plant height, cover, productivity and biodiversity, improve soil structure, fertility and microbial biomass, enhance carbon and nitrogen storage and reduce greenhouse gas emissions in the alpine grassland ecosystems.

Our knowledge of the spatial distribution of bryophyte diversity still suffers from low sampling efforts. Here we try to determine the spatial diversity patterns of liverworts and mosses and their environmental drivers more accurately by correcting for this sampling bias. We compiled bryoflora from 49 localities in eastern China, including data on sampling effort. Both sampling bias uncorrected (raw) species richness and bias corrected (estimated) species richness, as derived from species-sampling curves, were used as response variables. Model selection based on Akaike’s information criterion was used to evaluate the impact of collection bias on the selection of environmental and spatial variables in the regression models. Variation partitioning was used to assess the independent and joint effects of environmental, spatial and sampling variables on raw and estimated species richness. Liverwort richness increased significantly with decreasing latitude, while moss richness showed no latitudinal pattern, whether for raw or estimated species richness. However, estimated species richness showed stronger correlation with environmental variables than raw species richness. Importantly, selected environmental variables in the raw species richness models changed after correcting for collection bias. Despite their ability to produce copious amounts of spores, our sampling bias corrected models indicated that bryophyte richness showed strong spatial structuring, indicating dispersal limitation. Environmentally, liverwort richness was primarily controlled by water availability, while the richness of mosses was mainly determined by available energy. Our results highlight that biological features, dispersal ability and environmental sorting may account for the discrepancies between species richness of liverworts and mosses. Given the considerable impact that controlling for sampling effort had on analysis outcome, we like to stress the importance of controlling for sampling bias when studying spatial richness patterns in bryophytes.

With the rise of environmentalism in China, great efforts have been devoted to environmental protection over the past several decades. Compared with urban environmental protection, rural environmental protection has not been attached enough importance in China due to the dual-track structure of socio-economic development. As a result, rural China is shouldering disproportionally heavy environmental burdens partly because of the differences and biases between urban and rural environmental protection seen in environmental policies, environmental rights and interests, environmental protection investment, and the environmental protection awareness of people. To eliminate the gap between rural and urban environmental protection, and achieve the goal of “balanced urban-rural environmental protection” (BUREP), government should consider mapping out proper policies and strategies. In this paper we put forward an innovative strategy of BUREP against the background of China’s urban-rural environmental protection. First, we review the current status of rural environmental protection status and its challenges compared with urban environmental protection in China. Secondly, we analyzed the main driving factors and reasons deeply, and then we put forward the BUREP strategy base on the unequal status between urban and rural environment. Finally, we proposed the framework of BUREP. This study may serve as a scientific reference regarding decision-making in coordinating urban and rural environmental protection and in constructing the new countryside of China.

Nature reserves have developed rapidly over the decades in China and play a significant role in the function of ecosystem services. The function of ecosystem services in nature reserves, however, has tended to decline in recent years due to natural hazards and human activities. Based on land use, the variation of ecosystem services value (ESV) during 2000–2010 in national nature reserves in Sichuan was evaluated. We analyzed the comprehensive effects of natural disasters and human activities on the decline of ESVs. Total ESV in the national nature reserves in Sichuan was approximately 2741.35 million US$ in 2000, 2616.81 million US$ in 2005, and 2499.06 million US$ in 2010, representing a decrease of 242.29 million US$, or 8.84%, in the decade. Forestland, grassland, wetland, and water bodies played vital roles in the function of ecosystem services, with an aggregated ESV of 99% of the total. The largest proportion of the total ESV was the protection of biodiversity at 48.6%. ESV of all land use types and...

A long-standing task for ecologists and biogeographers is to reveal the underlying mechanisms accounting for the geographic pattern of species diversity. The number of hypotheses to explain geographic variation in species diversity has increased dramatically during the past half century. The oldest and the most popular one is environmental determination. However, seasonality, the intra-annual variability in climate variables has been rarely related to species richness. In this study, we assessed the relative importance of three environmental hypotheses: energy, seasonality and heterogeneity in explaining species richness pattern of butterflies in Eastern China. In addition, we also examined how environmental variables affect the relationship between species richness of butterflies and seed plants at geographic scale. All the environmental factors significantly affected butterfly richness, except sampling area and coefficient of variation of mean monthly precipitation. Energy and seasonality hypotheses explained comparable variation in butterfly richness (42.3 vs. 39.3 %), higher than that of heterogeneity hypothesis (25.9 %). Variation partitioning indicated that the independent effect of seasonality was much lower (0.0 %) than that of energy (5.5 %) and heterogeneity (6.3 %). However, seasonality performed better in explaining butterfly richness in topographically complex areas, reducing spatial autocorrelation in butterfly richness, and more strongly affect the association between butterflies and seed plants. The positive relationship between seed plant richness and butterfly richness was most likely the result of environmental variables (especially seasonality) influencing them in parallel. Insufficient sampling may partly explain the low explanatory power of environmental model (52.1 %) for geographic butterfly richness pattern. Our results have important implications for predicting the response of butterfly diversity to climate change.

Due to complex natural water flux processes and the ambiguous explanation of Bouchet’s complementary theory, site-level investigations on evapotranspiration (ET) and related climate variables assist in understanding the regional hydrological response to climate change. In this study, site specific empirical parameters were incorporated in the Bouchet’s complementary relationship (CR) and potential and actual ET were estimated by CR method and subsequently validated by 6 years of ground-based vapor flux observations. Time series analysis, correlation analysis and principal regression analysis were conducted to reveal the characteristics of climate change and the controlling factor(s) of the variations of potential ET and actual ET. The results show that this region is exhibiting a combined warming and drying trend over the past decades with two change points that occurred in 1993 and in 2000. Potential ET was predominantly influenced by temperature and vapor pressure deficit, while actual ET was mostly influenced by vegetation activity. Potential ET was found to be increasing concurrently with declining actual ET to constitute nearly a symmetric complementary relationship over the past decades. This study help to enhance our understanding of the regional hydrological response to climate change. Further studies are needed to partition the actual ET into transpiration and other components and to reveal the role of vegetation activity in determining regional ET as well as water balance.

Due to cold and arid climate of Tibet Autonomous Region, vegetation growth is considered to be controlled by both moisture availability and warmth. In order to reveal the patterns of regional climate change and the mechanisms of climate-vegetation interactions, long term (1982–2013) datasets of climate variables and vegetation activities were collected from Climatic Research Unit (CRU) and Global Inventory Monitoring and Modeling System (GIMMS). Principal regression analysis and (partial) correlation analysis were conducted to reveal the contributions of controlling factors on vegetation growth. Study results showed that (1) Annual mean air temperature (TMP) had increased by 0.38 °C per decade (P = 0.00) and annual precipitation (PRE) had increased by 17.25 mm per decade (P = 0.15). A significant change point around the year 1997/1998 was detected by Mann-Whitney-Pettit test, coinciding with the occurrence of El Niño event. (2) Normalized Difference Vegetation Index (NDVI) had an insignificant positive trend. Spatially, pixels of high NDVI values, great NDVI trends and high inter-annual deviations are distributed in the densely vegetated eastern part. Principal regression analysis revealed that, alpine grassland (northern and western part) is mostly controlled by temperature, steppe meadow (middle and southern part) is mostly controlled by precipitation, and shrub/mixed needle leaved and broad leaved forest (eastern part) is mostly controlled by cloud coverage. (3) Partial correlation analyses showed that regions with high sensitivity to precipitation nearly overlapped with regions of high sensitivity to minimum temperature. And the high importance of cold index (CDI, accumulated negative difference between TMP and 5 °C) revealed in this study implied the effects of regional glacial melting and permafrost degradation. We concluded that the regional climate change can be characterized as warming and wetting. Different regions and vegetation types in Tibet Autonomous Region demonstrated different driving climate factors and climate-vegetation relationships.

Precipitation is the main factor limiting the radial growth of Pinus sylvestris var. mongolica in the Hulunbuir region, northeastern China. We used tree-ring width data to reconstruct precipitation from prior August to current July during the 1829–2009. The reconstruction was verified by the jackknife method, and accounts for 60.49% of the actual precipitation variance during their common period (1951–2009). Over the past 181 years, the climate in the Hulunbuir region has experienced distinct dry–wet alternations at the decadal scale. The Hulunbuir area experienced seven wet periods and seven dry periods, and there was no significant long-term increase or decrease in precipitation. The reconstructed precipitation sequence for Hulunbuir was largely consistent with the precipitation sequence of Helan Mountain and Baiyinaobao in China. Multi-taper method spectral analysis found periodicities of 18.6, 7.2, 4.0, 2.7–2.8, 2.4 and 2.2 years in 0.05 significant level and 10.2, 8.9, 5.0 and 2.0 years at 0.1 significant level. Our reconstructions are significantly correlated with the intensity of the East Asia Summer Monsoon, El Nino/Southern Oscillation, Pacific Decadal Oscillation, Arctic Oscillation and North Atlantic Oscillation.

The relationship between ecological and socioeconomic systems in ecological function conservation areas (EFCAs) in China is analyzed from a governance perspective. Lashihai watershed in China’s southwestern Yunnan Province was chosen as a case study area, where leaders of 81 villager groups were interviewed through questionnaire surveys and anecdotal evidence was collected from focus group discussions. Our study found that the rehabilitated ecosystems in Lashihai, arising from conservation actions, provided the local communities with increasing natural capital to pursue horseback tourism as an important means of livelihood. Also, bonding social capital, together with unique cultural and ethnic assets, may have been instrumental in the formation of horseback tourism teams in some villager groups. However, the lack of higher-level government involvement and coordination among horseback tourism teams appeared to have led to a situation, where the rapidly developing tourism teams have started to impose threats on the wetland ecosystem. While highlighting some limitations of self-governance in adapting to complex and fast-changing socioeconomic conditions, the study called for the potential importance of fostering adaptive co-management to help modify the emerging undesired interconnectedness in social-ecological systems in Lashihai. For the future’s successful governance of integrated ecosystem management in EFCAs in China, the study also made brief discussion on some key elements of the adaptive co-management.

The correlation between tree-ring widths and climate was developed using Pinus sylvestris var. mongolica after which mean maximum temperatures of June–July since 1829 were reconstructed. Results show that the transfer function of temperature explains more than 40% of the variance and that the reconstruction sequence was consistent with several reconstructed temperature variations in the region. Over the past 181 years, climate in the region has undergone eight distinct low temperature and eight high temperature periods. A high temperature period in the 1920s to 1930s is consistent with a drought that occurred in most regions of northern China. Periods of drought in the 1870s were also identified. There was no significant increase or decrease in mean maximum June–July temperatures over the last 181 years, although since the 1950s temperatures have increased gradually. A warming trend has become more pronounced since the early 1990s but temperature levels are not significantly higher than those of the 1850s. A multi-taper spectral analysis shows that there are significant periodicities of 2.4, 2.8, 4.9, 5.1 and 21.3 years in the sequence of reconstructed temperatures. Temperatures were also affected by global climate events and solar activity.

This study was conducted to evaluate the toxicological response of p-nitrotoluene and p-nitroaniline to the key fish species, Cyprinus carpio. A freshwater fish bioassay based on the 96 h LC 50 was used to estimate the single and joint toxicity of the two chemicals. The toxicity of p-nitrotoluene was greater than that of p-nitroaniline based on 96 h LC 50 values of 40.74 mg·L−1 and 48.99 mg·L−1, respectively. Both compounds had moderate toxicity toward Cyprinus carpio, and this toxicity increased with the exposure duration and concentration. Binary mixtures of the compounds were more toxic than the individual compounds at 96 h, and they acted upon partial addition. When the exposure time was longer, the toxicity increased for mixtures of compounds with the same concentration or toxicity. The results of this study suggest that exposure to a combination of these chemicals would result in a higher environmental risk in aquatic systems than exposure to either compound alone. Further research is needed to investigate the combined effects and sublethal toxicity of p-nitrotoluene and p-nitroaniline, since they are both still used in China.