The principles of mountain-river-forest-farmland-lake-grass system (referred as meta-ecosystem) are important for ecological conservation and restoration. Based on the concept of meta-ecosystem, the principles of ecological conservation and restoration for meta-ecosystem were preliminarily discussed from the perspective of ecosystem integrity, health and stability. Facing the current ecological environmental issues, the ecosystem characteristics and the China's strategy for ecological conservation and restoration, the content of ecological conservation and restoration for meta-ecosystem. The contents include the survey and assessment of background, the maintenance of protection achievements, the conservation and restoration of degraded ecosystem, optimization of biodiversity conservation pattern, the improvement of ecological migration and industrial upgrading, the demonstration of ecological conservation and restoration, and the construction of integrated information system. Moreover, projects of ecological protection and restoration for meta-ecosystem, which are carrying out in Shaanxi, Hebei, Gansu, Jiangxi and Qinghai, have been presented.

Research on ecosystem service supply-demand relations is necessary for effective ecosystem management, land development planning and rational allocation of resources. Two indicators, ecosystem service supply rate and supply-demand ratio, were formulated and applied in a case study to compare and map the spatial-temporal status of ecosystem services and the ability to supply these in different regions. Using Beijing-Tianjin-Hebei Region as an example, data obtained from high-resolution spatial land cover maps and stakeholder interviews were used to identify the spatial-temporal potential supply and flow of ecosystem services and human patterns. The results show that ecosystem service supply-demand ratio declined from 1990 to 2015, indicating that the overall proportion of potential ecosystem services turned into flow in the Beijing-Tianjin-Hebei Region declined. Determination of supply rate revealed that the status of ecosystem service provision in the Beijing-Tianjin-Hebei Region remained steady from 1990 to 2015. The ecosystem service supply-demand status of Hebei and Tianjin were in surplus, meanwhile Beijing was in deficit. The supply-demand situation of ecosystem services in Beijing and Tianjin became worse from 1990 to 2015. From the perspective of space, the supply and demand of ecosystem services in the northwest of Beijing-Tianjin-Hebei region was in surplus state, and the rest was in deficit state in the southeastern area except Beijing, Tianjin and Shijiazhuang. Compared with 1990, the change of supply-demand situation of ecosystem services in the northwest area in 2015 is very small, and the deficit range of supply and demand of ecosystem services increased sharply with the rapid expansion of cities such as Beijing, Tianjin and Shijiazhuang.

Carbon emission from different agricultural activities (e.g., fertilizers, pesticides, agricultural films, irrigation, tilling and diesel utilization) in Hunan Province during the periods of 1999-2014 were calculated. Its relationship with agricultural economy was further investigated using the environmental Kuznets curve model. The carbon emission and agricultural economy in Hunan Province represented several decoupling relationships between them, such as significantly negative, weak and weakly negative decoupling relationships. The data indicated a trend of "rapid growth phase—rapid descent phase—stationary phase" between the carbon emission and agricultural economy. In addition, the amounts and intensity of carbon emission significantly increased (a logarithmic growth mode) with a sustainable development of agricultural economy. The results suggest that the agricultural development in Hunan Province faces several key problems, such as high resource consuming, low efficiency of resource utilization and negative effects on the environment.

Compensation for ecological services is an environmental policy which is effective for biodiversity protection. The willingness of farmers, as the main stakeholders, to participate in such a compensation project directly affects the performance and sustainability of the project. Based on an investigation of the ecological environment of the tidal flat in Yancheng City, a questionnaire was designed using payment card, and 125 farmers residing around the Yancheng Rare Bird Nature Reserve were interviewed face to face. The contingent valuation method (CVM) was used to analyze their willingness to accept (WTA) compensation. The basic social and economic characteristics of the farmers, such as their gender, age, annual income, acknowledgement of compensation for ecological services, and attitude toward environment projects, were selected as the independent variables. Next, taking the farmers' willingness to accept compensation as the dependent variable, the binary Logistic model was used to analyze the influencing factors affecting the farmers' WTA. The results show that the farmers residing around the protected area possessed a certain degree of awareness of environmental protection. A total of 88% of the farmers chose a non-zero WTA, with an average minimum WTA compensation of RMB 7 727.7 Yuan·hm^-2·a^-1. The analysis of the Logistic model show that the age of the farmers, acreage of farmland, and acknowledgement of compensation for ecological services were the major factors affecting their WTA compensation. The results of this study offer suggestions regarding the effective implementation of compensation for ecological services in the Yancheng Rare Bird Nature Reserve, while also provide a scientific reference for that in other protected areas.

As the main mode of sustainable agricultural development, green production is not only advocated by the government, but also the future guiding trend of cultivating. The progress and status of the sustainable development of agriculture depends on the consciousness of the households in cultivating in green ways. Based on the survey data of households in Hubei and Shandong provinces as well as the survey data of national farmers' cooperatives to analyze the influence of family economic conditions on households' ecological consciousness for adopting green production. The results show that family economic condition is an important factor that significantly influences households' ecological consciousness. Raising family economic situation is useful to improve households' consciousness to return crop straw back to the fields and to reduce pesticide use. However, households do not have enough ecological consciousness to reduce the chemical fertilizer input. It is necessary for households to change their traditional behaviors and to apply fertilizer more reasonably. Research results also reveal that farming duration, land acreage, number of family members, technical support and provincial differences also have effects on households' ecological consciousness to adopt green production practices. Therefore, the government should focus more on households' income diversification and strive to improve their economic conditions. On the basis of this, the government should also actively nurture new types of professional farmers and intensify research and development of new and practical agricultural machines according to local conditions so as to promote the formation and improvement of farmers' ecological consciousness.

It is important to accurately assess carbon sequestration ability and trends in forest ecosystems to achieve sustainable forest carbon sinks. Based on forest inventory data of four times in China, the carbon storage and carbon density of forest vegetation in Yangtze River Basin were assessed by means of the regression equation between vegetational biomass and volume, and with the carbon fraction of dry matter. The results show that the carbon storage of forest vegetation increased from 1 345.30 Tg to 1 924.98 Tg during the period of 1989-2008 in Yangtze River Basin, with an average annual growth rate of 2.15%, which was 0.29 percentage point more than that of the mean increment of China, implying that the potential of carbon sink of forest in Yangtze River Basin was increasing. Correspondingly the average carbon density of forest vegetation was 42.25, 40.34, 41.00 and 41.42 Mg·hm^-2, respectively. The carbon storage of forest vegetation mainly concentrated in young, middle-aged and near-mature forests, and the contribution of them to the carbon stock of the stands exceeded 85%, indicating that the carbon sequestration potential of forest vegetation was large. Carbon storage of forest vegetation was mainly distributed in natural forests, accounting for more than 78% of the total carbon storage in the same period. However, the carbon storage capacity of plantations was gradually increasing. The proportion of carbon storage in plantations to the forest carbon storage in the same period showed an increasing trend, and the carbon density of plantations was obviously smaller than that of natural forest, indicating that plantations would play an important role in sequestrating carbon by forest vegetation. The middle and upper reaches of the Yangtze River were the major contributors to the carbon storage of forest vegetation in the basin, accounting for more than 96% of the carbon storage of forest vegetation in the whole basin. Furthermore, the results also show that forest vegetation in Yangtze River Basin played an important role in the national forest carbon storage and enhancement of the national forest carbon sequestration function.

The infrared camera data in this study were collected in four nature reserves (Wanglang, Siguniang Mountain, Gongga Mountains and Yading) of Sichuan Province through the Chinese Mammal Diversity Observation Network from June to November, 2017. Relative population and daily activity rhythms of nine ungulates were studied using the relative abundance index (RAI), including Budorcas tibetanus, Capricornis milneedwardsii, Cervus unicolor, Elaphodus cephalophus, Moschus berezovskii, Moschus Chrysogaster, Muntiacus reevesi, Naemorhedus griseus and Pseudois nayaur. The results show that:(1) E. cephalophus had the highest RAI (64.12%), which was significantly higher than others. (2) E. cephalophus, M. reevesi and N. griseus showed a bimodal activity pattern with peaks at dawn and dusk. (3) C. milneedwardsii and C. unicolor showed obviously higher levels of nocturnal than diurnal activity. (4) E. cephalophus had similar daily bimodal activity patterns with different activity peaks in different areas. It is indicated that the ungulates' population was related to food resources and predation pressure, and their daily activity rhythms may be influenced by many biotic and abiotic factors. This study can provide the basis for monitoring, protection and management of ungulates in a more efficient way, and offer the data support for the behavior study and conservation of their predators.

Corncob-made biochar (C4) was amended to a paddy field which was newly developed from the Yangtze River sediment. After one-year biochar amendment the soil was fractionated to investigate the effects of biochar amendment on soil carbon fractions, as well as the carbon decomposition of such fractions during incubation. The distribution of biochar in soil fractions was quantified based on the different carbon isotope abundances between biochar and native soil organic carbon (nSOC, C3). The results indicate that biochar amendment significantly enhanced the organic matter content of aggregates at all size levels. 76%-90% of biochar existed as free particles in the macroaggregate (>250 μm) and microaggregate (>50-250 μm) fractions; only a minor proportion of biochar showed relatively tight interactions with soil aggregates or <20 μm mineral particles. These suggest that biochar amendment had not enhanced the formation of soil aggregates. Biochar itself decomposed extremely slowly during incubation of various soil fractions, but its amendment promoted the decomposition of nSOC. To conclude, the application of biochar alone did not significantly promote the soil carbon stabilization of entisols, but instead may accelerate the soil carbon decomposition in the short term.

In order to evaluate the contamination level and explore the spatial distribution pattern of heavy metals in greenhouse soils of China, the peer literatures on heavy metals in greenhouse soils since 1997 were systematically reviewed and the data analyzed. The results indicate that the heavy metals in greenhouse soils of China generally showed a spatial distribution pattern. The concentrations of Cd, Pb and Hg in greenhouse soils are higher in the south, the concentrations of As, Cu, Zn and Cr are higher in the north, while the value for Ni is the highest in the northwest. Moreover, 41.7%, 54.5% and 11.1% of soil sample sites from the south, north and northwest, respectively, showed higher Cd concentration than the standard value for farmland of greenhouse vegetables production; while for Pb concentration, 33.3%, 18.2% and 0 of the soil sample sites in the three regions respectively, exceeded standard value. The geo-accumulation index shows that for the greenhouse soils in China, Cd pollution is the most serious, followed by Hg pollution. In addition, the concentrations of heavy metals accumulated in greenhouse soils in China increase accordingly with planting years, and the heavy metals concentrations decrease with the soil layer. The main source of heavy metals in greenhouse soils is fertilizer, especially manure.

Taking groundwater of a mining area in central Hunan as the research object, concentrations of 15 heavy metals in 14 monitoring wells in the mining area were monitored and analyzed. The results show that As, Sb, Co, Fe and Mn concentrations in the groundwater were 14.3%, 64.3%, 50.0%, 10.7% and 14.3% greater than the standards of GB/T 14848-2017 and GB 3838-2002 respectively, with the maximum concentrations of 5.4, 30.4, 0.9, 34.0 and 18.3 times of the standards. The significantly greater concentrations of Sb indicated that the pollution of Sb in the groundwater is the most serious. The results of the pollution assessment show that the proportion of heavy pollution of the groundwater in the mining area was 78.5% in dry season, while the proportion of heavy pollution was 50% in the wet season. The possible health risk of the polluated groundwater to local inhabitants were assessed based on the the groundwater health risk assessment model. The results show that the health risk of the polluted groundwater was mainly from As, Sb and Co via consumption. The carcinogenic risk value of As via consumption was in the range of 1.08×10^-3-2.89×10^-3, which far exceeded the limit for acceptable maximum carcinogenic risk level. The maximum non-carcinogenic hazard quotient of As, Sb and Co were 1.48×10², 89.2, 69.0, respectively, all above the acceptable level, which can be harmful to the health of the local sensitive population through drinking groundwater.

The performance of volatile fatty acids (VFAs) and methane production during anaerobic digestion of cereal straw (rice, wheat and sorghum straw) and its three-dimensional excitation emission matrix fluorescence spectroscopic characteristics were investigated in an automatic biochemical methane potential test system inoculated with rumen fluid. The results show that, rumen microorganism from dairy cattle owns strong hydrolysis and acidification ability for cereal straw. After 5 d of anaerobic digestion, the amount of total VFAs (TVFAs) for rice, wheat and sorghum straw were 410.9, 430.9, and 472.0 mg·g^-1 volatile solids (VS), respectively. The modified Gompertz model fits well to methane producing profile of cereal straw. After 55 d of operation, the corresponding methane yields were 66.29, 103.79, and 76.89 mL·g^-1 VS, respectively. Three fluorescence components, i. e., tyrosine-like, tryptophan-like and humic-like substances with low molecular weight, were identified in dissolved organic matter, using three-dimensional excitation emission matrix (EEM) fluorescence coupled with parallel factor analysis (PARAFAC). The relationship between fluorescence intensity of the tryptophan-like materials and TVFAs could be well expressed by a power function. The humidification index (HIX) of dissolved organic matter decreased after 5 d and then increased gradually during anaerobic digestion.

The method of emission factors was adopted to estimate and analyze the distribution characteristics of ammonia emissions of livestock and poultry breeding industry in the Yangtze River Delta (YRD). The livestock ammonia emissions of 16 cities in the YRD in 2015 were estimated based on the activity data and emission factors of various ammonia sources. Results show that the livestock ammonia emissions in the YRD reached 214.5 kt in 2015, of which 14.03% were from non-scale, and 85.97% were from intensive cultivation. The ammonia emissions from pigs, sows, meat birds, egg birds, sheep and cows accounted for 41%, 2%, 27%, 15%, 12% and 3%, respectively. Nantong and Taizhou are the geographical centers of ammonia emission in the YRD, and the spatial distribution of ammonia emission tended to be high in the north and low in the south. The three cities which had higher intensity of ammonia emission are Nantong, Changzhou and Taizhou, whose intensity of ammonia emission was 5.47, 5.20 and 4.04 t·km^-2, respectively. Obvious monthly characteristics of ammonia emission coefficient were investigated and it was large in summer (July and August) and small in winter (December and January).

Three typical chlorinated alkyl organophosphate flame retardants (OFRs-Cl), including triphosphate (1,3-dichloro-2-propyl) ester (TDCPP), triphosphate (2-chloro-propyl) ester (TCPP) and triphosphate (2-chloro-ethyl) ester (TCEP), were emerging pollutants for the environment. In the present study, the acute toxic effects of TDCPP, TCPP and TCEP on the fourth instar larvae of Chieonomua riparius were examined by spiked water method. The results show that 5.0 mg·L^-1 TDCPP and TCEP promoted the emergence of larvae, and the promotion effect of TDCPP was stronger than TCEP. All three types of OFRs-Cl had significant effects on the antioxidant enzymes of the larvae of midges. The activities of SOD and CAT in the larvae were induced positively with the increase of OFRs-Cl concentration, and that of MDA was increased at 5.0 mg·L^-1. The expression of HSC70 gene was significantly up-regulated at 5.0 mg·L^-1 of TDCPP and TCEP, and was significantly down-regulated at 5.0 mg·L^-1 of TCPP. In the presence of TDCPP, TCPP and TCEP induced stress, the expression of CYP4G gene were all down-regulated, while the down-regulation was the most significant under TDCPP stress than TCPP and TCEP. A dose-effect relationship was confirmed between TDCPP and SOD or MDA. Different enzymes and genes showed different sensitivity on three OFRs-Cl, yet detoxifying enzymes and related genes showed no significant correlation. Different indexes could be selected as biomarkers for monitoring the varied toxicity derived from three OFRs-Cl on C. riparius.