Climate change is one of the most serious challenges that mankind is facing in the 21st century. Under climate change, the increase of extreme climate risk has intensified the vulnerability of farmers' livelihoods. Rural households, who are the basic units of rural communities, have to cope with climate change with adaptation as the main way. Therefore, various adaptation strategies have been adopted based on household livelihood assets and the environment. This paper provides a systematic review of current researches on rural households'adaptation strategies to climate risks from two perspectives. The first is the typology of adaptation strategies and the influencing factors of decision making, and the second is theassessment of the effectiveness of these adaptation strategies. On this basis, an analytical framework of influencing factors on the decision-making of adaptation strategies to climate risks was put forward.At the same time, the paper points out some deficiencies in current researches and provides suggestions for future research, aiming at promoting the researches on rural households' adaptation to climate change and improving relevant adaptation practices.

A scientific-based understanding of temporal and spatial patterns and driving factors of urban surface thermal fields is an important prerequisite for the upgrading of urban ecosystems. Kashgar City, the throat hub of civilization and transportation between the East and the West, features heavily in the Belt and Road initiative. Landsat series of remote-sensing images in 1998, 2008, and 2018 of Kashgar on the western edge of the Tarim Basin were adopted in this study. The land surface temperature (LST) was retrieved with the radiative transfer equation algorithm and the spatial variation of surface temperature in Kashgar City was analyzed through transfer matrix with the help of GIS and RS technology. On the basis of extracting impervious surface index (IBI) and vegetation coverage (FVC), 6 types of influencing factors including altitude, slope, population density, IBI, FVC and land use type were integrated to detect the spatial heterogeneity and driving factors of the surface thermal field with geographic detectors in Kashgar City in the past 20 years. The results show that: The medium temperature and the higher temperature areas were contiguously distributed in the urban built-up area, the low temperature and lower temperature areas were inlaid in the periphery of the built area in dots, and the high temperature and extremely high temperature areas were distributed in patches in the north of the urban area. With the rapid development of the region, the medium temperature area has gradually dominated the whole area. In 2018, the area of the medium temperature zone was 161.89 km², but due to the coexistence of cropland invasion, urbanization and forestation, the area of low temperature zone increased by 4.58% with bare lands effectively improved, and the area of the high temperature and ultra-high temperature zone saw a drop of 20.41 km². The spatial differentiation of the surface thermal environment in Kashgar is the result of multiple factors. IBI represents the core factor affecting the spatial differentiation of LST with the contribution rates of 1998, 2008 and 2018 to be 87.8%, 74.6%, and 80.8%, respectively, and the multi-factor interaction is obvious. The interactive explanatory powers of IBI and land use types in 1998, 2008 and 2018 were 0.912, 0.746, and 0.873, respectively. The research results can provide reference for urban ecological protection and sustainable regional development in Kashgar City.

Water ecological health of upstream watershed of Miyun Reservoir plays an important role in ensuring water safety of Miyun Reservoir. In order to systematically evaluate the health status of river ecosystems in the upstream watershed of Miyun Reservoir, a survey was conducted on macrobenthos in 2019. A total of 39 sampling points were set up, and 128 species of benthos were collected, including 106 species of Arthropods, 16 species of Molluscs, 5 species of Annelida, and 1 species of Platyhelminthes. From the perspective of pollution tolerance, the proportion of sensitive groups was 23.1%, and the proportion of pollution-tolerant groups was 0.9%. In terms of the occurrence frequency of groups, the top three benthic animals were Ephemera, Cheumatopsyche and Stenopsyche McLachlan, with the occurrence frequencies of 82%, 79% and 74%, respectively. The three benthic animals were all indicative organisms of the clean class. With macrobenthos as indicator organisms, the distribution range analysis, discriminant ability analysis and correlation analysis of 44 candidate biological indicators were carried out. The B-IBI index system of the upstream watershed of Miyun Reservoir was constructed by five indicators, namely, total taxa, the percentage of individuals of sensitive taxa, the percentage of Ephemeroptera individuals, the percentage of aquatic insect classification units and the percentage of sensitive groups. The quartering method was used to unify the parameter dimensions, and the 25% quantile method of the reference point B-IBI value distribution was used as the evaluation standard for river ecosystem integrity. The results show that 23% of the samples were at the "health" level, 33% at the "sub-health" level, 33% at the "normal" level, 8% at the "poor" level, and 3% at the "extremely poor" level.

The concentrations of As, Cd, Hg, Pb, Cr, Cu, Mn and Zn in water bodies and surface sediments were monitored to explore the pollution condition of heavy metals in the water environment of Taiyangshan National Wetland Park in Ningxia in winter, spring, summer and autumn of 2019. Multivariate statistical methods were used to analyze the temporal and spatial heterogeneity of heavy metals in the water environment, and Nemerow Comprehensive Pollution Index Method and Geo-accumulation Index Method were used to assess the pollution status of heavy metals in the water environment. The results show that the heavy metal contents of the waterbody were generally at low level and only the Hg content exceeded the Ⅲ class surface water standard of the "Environmental Quality Standard for Surface Water (GB 3838-2002)". The surface sediments were seriously polluted by heavy metals except for Cr, which did not exceed the soil background value of Ningxia. The contents of heavy metals in water and sediments were higher in the east part of the lake and lower in the south part of the lake. The heavy metal pollution level of the waterbody as a whole was low by usinig Nemerow Comprehensive Pollution Index Method. While the most serious pollution was found in the west part of the lake and in winter. Among the heavy metals, Hg contributed the most to the pollution. By using the Geo-accumulation Index Method, it was found that the surface sediment was most seriously polluted in winter and Hg contributed the most to the pollution.

The problem of soil heavy metal pollution is becoming increasingly serious. Identifying the sources of soil heavy metal pollution has important guiding roles for pollution prevention and risk control. In this study, a concentrated distribution area of agricultural soils in the Pearl River Delta was selected to study the pollution characteristics and sources of heavy metals in soils by multiple methods including correlation analysis, elements distribution in soil profile, isotope ratio, principal component analysis and positive matrix factorization (PMF). The results show that the highest cumulative element in surface soil was Mercury (Hg), followed by Cadmium (Cd) and Zinc (Zn), and their average concentrations were 3.22, 1.29 and 1.09 times of the regional soil background values of the Pearl River Delta, respectively. The average concentrations of Arsenic (As), Lead (Pb), Chromium (Cr), Nickel (Ni), and Copper (Cu) were lower than the regional background values. The concentration of Hg in soil was only significantly positively correlated only with Pb,showing that Hg and Pb had the same sources. The obvious characteristics of surface layer aggregation of Hg and Pb in soil profile indicate the exogenous input. The combination of principal component analysis and stable isotope ratio can further identify the sources of Hg and Pb, which was highly correlated with the input of human activities such as industry and transportation. The results of PMF show that the accumulation of Hg and Pb in the soils of the study area was mainly caused by artificial sources such as industrial activities, and Cr and Ni in the soils were mainly from natural geological background, and Cd, Cu, Zn and As were greatly affected by both material migration and deposition from the upper drainage basin and natural geological background. When analyzing the cause of regional agricultural soil pollution, the rationality and reliability of the analytical results can be improved by the mutual verification of the combination using of different methods.

Contamination of agricultural soil by heavy metals has become a global issue concerning food security and human health risk. A total of 95 surface soil samples (bulk soil), 34 vegetable samples, 27 irrigation water samples, and 20 fertilizer samples were collected from Wuqing District, Tianjin, China. The concentrations of heavy metals (i.e., As, Cd, Cu, Cr, Ni, Pb, and Zn) in these samples were tested. After determining the metal accumulation and potential ecological risks in farmland soil, kriging interpolation and positive matrix factorization (PMF) were used to identify and quantify the sources of soil heavy metals. The results showed that (1) Cd and As were the main contaminants in the soil in the studied area, and Cd had the highest effectiveness in soil, with its average content in vegetables slightly higher than the allowable threshold (0.02 mg·kg^-1). (2) The results of the enrichment index of vegetables show that Cd and Pb were the dominant heavy metals in vegetables, and vegetables had a strong enrichment ability to Cd. (3) The spatial distribution of heavy metals in the soil showed that the contaminants were non-homogeneous, and all the heavy metals showed high-value areas in some parts of the studied area, indicating the negative effects of human activities on the soil environment of farmlands. (4) Industrial activity (for Cd), effects of pesticides, fertilizers, and plastic film mulching (for As and Pb), natural sources (for Ni, Cu, Cr, and As), Organic fertilizer (for Zn and Cu), traffic discharges (for Pb and Cd) and sewage irrigation (for Cr, Ni, and Pb) were ascertained as the potential sources based on the Positive matrix factorization (PMF) analysis results. (5) The accumulation of heavy metals in the studied area was mainly caused by industrial activities, including atmospheric deposition, the discharge of industrial waste water, the disposal of waste residue, and the emission of waste gas, and so on.

Field survey and literature searching were conducted to develop a species list of lycophytes and ferns in Jiangsu Province, China. A total of 184 species (including subspecies, varieties, forms) belonging to 66 genera and 30 families were found, of which 176 species of 61 genera from 27 families were wild plants and 8 species of 7 genera from 6 families were cultivated. The dominant families were Dryopteridaceae (41 species), Pteridaceae (17), Thelypteridaceae (17), Athyriaceae (16); dominant genera were Dryopteris(26), Asplenium(15), Selaginella(8), Polystichum (8). The geographical components of families and genera included 6 and 10 categories, respectively, and both were dominated by pan-tropical elements. Moreover, the geographical components of species included 11 categories, in which East Asian and endemic to China predominated. In addition, the total number of species can be grouped into 5 distribution types, in which the terrestrial ecological group was the most dominant. According to floristic similarities at the level of family, genus, and species, Jiangsu flora was most closely allied to that of Anhui Province, but was less closely allied with that of Zhejiang Province, and distinct from that of Shandong Province. In summary, Jiangsu is relatively rich in lycophytes and ferns, with distinct dominant families and genera, complex floristic elements, and temperate floristic nature in the flora. It is suggested to promote conservation of the endangered lycophytes and ferns in Jiangsu Province.

The biodiversity and population dynamics of amphibians are the basis of amphibians conservation. During the period of 2014-2018,amphibian species composition and population dynamics in Leigongshan National Reserve of Guizhou Province were investigated by using the transect sampling method. The results show that:(1) a total of 28 species and subspecies were found in the survey which belonging to 2 orders, 8 families and 16 genera, including 2 endangered species, Vibrissaphora leishanensis and Quasipaa boulengeri, 13 species recorded only in China and 4 species recorded only in Guizhou Province; (2) Megophrys leishanensis, Megophrys spinata, Odorrana huanggangensis, Hylarana guentheri, Nidirana leishanensis and Paramesotriton caudopunctatus were the dominant species in the reserve; (3) more amphibians were observed in June than in August and October; (4) the number of species and individuals of Amphibians at altitudes of 800-<1 200 m were higher than those at other altitudes; (5) the number of species and individuals observed over the five years were with varying degrees of fluctuation and all bottomed out in 2018.

From July 2017 to October 2019, an inventory survey of large mammals and birds was conducted in Liupanshan National Nature Reserve in the Ningxia Hui Autonomous Region using camera-trapping. In total, 56 901 photographs and 2 883 videos were obtained with an intensive survey effort of 47 460 camera-days from 60 locations. 19 wild and 4 domestic species belonging to 11 families and 5 orders were identified from 41 710 photographs and 1 733 videos of mammals. Among the detected mammal species, 2 species were listed as Class Ⅰ state key protected wild animals in China and 3 were listed as Class Ⅱ. Carnivora and Artiodactyla were the 2 mammalian orders with the largest number of effective photos (9 922 and 25 114) and accounted for 23.78% and 60.19% of the total number of detections, respectively. The species with the highest relative abundance index in the Carnivora order was the pig badger (Arctonyx collaris, 5.008), and the most frequently observed species in the cloven-hoofed order was the wild boar (Sus scrofa, 7.206). 12 861 photographs and 964 videos of birds were recorded, including 53 species belonging to 15 families and 6 orders, among which 3 species were listed as Class Ⅱ state key protected wild animals in China. Phasianidae was the most frequently detected Galliformes and accounted for 48.08% of total bird detections. Of the observed species, Cinclidium leucurum, Garrulax lunulatus, Muntiacus reevesi, and Hystrix brachyura had not previously been recorded in Ningxia (including Liupanshan National Nature Reserve), and Martes flavigula and Naemorhedus griseus had not previously been recorded in Liupanshan Reserve. These new observations expanded the distribution range of these species in China. Thus, these discoveries have enriched current distribution information of these species. The research results provide comprehensive baseline data regarding the large mammal and bird community within Liupanshan, which will support and guide future management and long-term monitoring of Liupanshan Reserve.

Xiamen Bay is rich in ecological resources and has diversified service functions. However, due to the comprehensive action of natural, human activities and other factors, Xiamen Bay ecosystem is under great pressure. Dynamic simulation of ecosystem can provide scientific basis for the analysis of biomass variation, energy flow variation and ecosystem stability. An EwE model was developed based on the fishery resources survey data of Xiamen Bay in 2019-2020, and was compared with the model used in 2010. Totally 26 functional groups were included in this model, such as marine animals, bamboo shark, fanray, anchovy, terapon, shrimps, crabs, cephalopods, zooplankton, phytoplankton, benthos, detritus, et al, which have basically covered the whole energy flow pathway in the ecosystem of Xiamen Bay. Results show that the large predators in Xiamen Bay was relative few, leading to the low pressure on Xiamen Bay ecosystem predation, and the dominant position of low trophic level creatures like small fishes occupied in the ecosystem. The ecosystem structure of food web in Xiamen Bay was relatively simple, and the stability of the ecosystem is currently low. Compared with the results of the model used in 2010, the functional groups and energy flow in Xiamen Bay had changed in 2020. The biomass, detritus flow and total throughput in the lower trophic levels of the ecosystem in 2020 were less than that in 2010, while those in the higher trophic levels were higher than that in 2010. In general, total system throughput of Xiamen Bay ecosystem in 2020 was smaller than that in 2010. This study can provide scientific basis for the protection and management of Xiamen Bay ecosystem.

Vegetation types affect the structure and function of terrestrial ecosystems and landscape patterns, as well as the structure and function of soil microbial communities. This study selected 10 vegetation types including slope farmland, check-dam farmland, orchard garden, artificial caragana korshinskii shrubland, artificial Robinia pseudoacacia forest, abandoned farmland, Artemisia sacrorum grassland, Periploca sepium shrubland, Sophora viciifolia shrubland, and Platycladus orientalis forest for sampling in the loess hilly region. Soil physico-chemical analysis and soil microorganisms 16srRNA gene using high-throughput sequencing technologies analysis were used to reveal the characteristics of the soil bacterial community structure and function, and to identify the relationship between environmental factors and soil microbial community among different vegetation types. The results showed that Proteobacteria and Actinobacteria were the dominant groups of soil microorganisms in the soil bacterial community, followed by Acidobacteria, Chloroflexi, Gemmatimonadetes, Bacteroidetes and Verrucomicrobia. The α diversity index of soil bacterial community under natural vegetation types was slightly higher than that under artificial vegetation types, but only ACE index of soil bacterial communities had significant differences among different vegetation types (P<0.05). The similarity clustering analysis based on genus level reflected that the similarity relationship of different soil bacterial communities can objectively related to the characteristic of different vegetation types. Unknown function, and amino acid transport and metabolism were the dominant functional groups in the soil bacterial community. RDA analysis showed that total carbon, total nitrogen, organic carbon, electrical conductivity, pH, nitrate nitrogen, and soil moisture were the key environmental factors which affected soil bacterial community. Correlation heatmap analysis showed that there was a significant correlation between the dominant genera and environmental factors. Vegetation types had an important influence on the composition and function of soil bacterial community. The characteristics of soil microbial community showed a comprehensive response to the biological characteristics of dominant species, vegetation succession, soil properties, and human management of different vegetation types. Therefore, vegetation types is an important driving factor for soil bacterial community structure and function in the Loess Hilly Region.

Using high throughput sequencing and real-time PCR techniques,the effects of added Zn on relative abundance of aminoglycoside antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and bacterial communities in soil were studied by indoor culture. The results show that Zn concentration and treatment time had different effects on aminoglycoside ARGs and MGEs.After treatment with 1 000 mg·kg^-1 Zn for 60 d, the relative abundances of acc, aacC1 and integron int11 were the highest, which were 4.1, 9.7 and 3.7 times as those of the control, respectively. When 800 mg·kg^-1 Zn was treated for 60 d, the relative abundance of aac(6')-Ⅱ was the highest, which was 13.7 times as that of the control. The relative abundance of transposon Tp614 was significantly increased only after 60 d of Zn treatment, and the highest relative abundance was obtained at 100 mg·kg^-1 Zn treatment, which was 4.6 times that of the control. Zn stress decreased the diversity index of bacterial community and increased the dominance index, indicating that Zn toxicity caused the disappearance of sensitive bacteria and the increase of resistant bacteria. Redundancy analysis show that the effect of Zn stress duration on bacterial community structure was greater than that of Zn concentration. When the treatment time was equal, the structure of soil bacterial community was significantly different between low concentration Zn (100-400 mg·kg^-1) and high concentration Zn (800-1 000 mg·kg^-1). Zn treatment was negatively correlated with Nocardioides, Adhaeribacter and Arthrobacter, and positively correlated with Flavisolibacter, Sphingomonas and Solirubrobacter. The network coexistence analysis show that acc, aac(6')-Ⅱ, aacC1 and int11, IS613 had high connections under Zn stress; Steroidobacter was connected to Tp614, which may be the potential host of Tp614. The studies have shown that high concentration of Zn pollution can accelerate the spreading and diffusion of soil ARGs. Even if low concentration of Zn exists for a long time, some ARGs and MGEs can be induced, and the risk of horizontal transfer can also be increased, which is worthy of attention.

To investigate the effects of microplastics on biological growth and metabolism in culture environment, Chinese mitten crab (Eriocheir sinensis) was selected to be exposed in different particle sizes(5 and 50 μm) and different concentrations (0.1, 1, and 10 mg·L^-1) of microplastics for 28,35 and 42-day toxicity test. Survival and weight gain rates were recorded to evaluate the effect of microplastics on the growth of crabs. Superoxide dismutase (SOD)、catalase (CAT) activities, and malondialdehyde (MDA) content in the hepatopancreas of the crabs were measured simultaneously to study the effects of microplastic on antioxidant enzyme activities. The results show that exposure in microplastics did not affect the survival rate of juvenile crabs, but there was a decreasing trend in the weight gain as the exposure concentration increased. The variation of SOD and CAT activities in the hepatopancreas of 5 μm groups was greater than that of 50 μm groups. Small-sized microplastics had a greater influence on the oxidative stress system than big-sized microplastics in E.Sinensis, but without significant regularity. At the same concentration, there was a significant effect in the middle stage of treatment. SOD and CAT activities were most induced in the 35 days of exposure. SOD activities were inhibited to different degrees in the early exposure, while CAT activities showed a trend of increasing first and then decreasing with the exposure time. With prolonged exposure time, the induction effect gradually weakened until the 42nd day. The content of MDA reached the highest level on the 28th day of exposure, then the increasing trend of MDA content gradually decreased. Under the same exposure time, the effect of low concentration of microplastics was significant, while the high concentration of microplastics exposure produced some inhibitory effect. The results indicate that the low concentration of microplastics could cause oxidative stress to E. Sinensis for a short time and affect the activity of the antioxidant system in the hepatopancreas, while high concentration of microplastics for a long time could significantly inhibit the activity of various enzymes in the hepatopancreas, causing damage to the oxidative system in juvenile crabs.

Microplastics(MPs)are prevalent in fresh water all over the world. Previous studies have shown that MPs pollution in the freshwater environment of China is particularly severe. Once ingested by aquatic organisms, MPs can be transmitted through the food chain and accumulated in high trophic organisms, which indirectly endangers the quality and safety of aquatic products, and eventually may become a potential threat to human health. However, most of the researches on MPs have been focused on marine ecosystems, and less been conducted for freshwater ecosystems, while freshwater ecosystems are more closely linked to and affected by human activities. In order to investigate the extent of MPs contamination in farmed river crabs (Eriocheir sinensis), the muscle and hepatopancreas tissues of Eriocheir sinensis, bottom water and bottom sediment from five aquafarms in Jianli city and Honghu city, Hubei Province were examined by chemical digestion combined with Raman spectroscopy. The results show that MPs were not detected in the muscle tissue and bottom sediment, but were detected in the hepatopancreas tissue of three aquafarms (mean abundance 1.22 g^-1), and in the bottom water of one aquafarm (0.13 L^-1). The shape of all detected MPs was mainly fragmented (74.28%) and the rest were granular; the chemical composition was polystyrene (PS), polyethylene (PE), and fluorinated ethylene propylene copolymer (Teflon FEP). All the detected MPs were classified according to color as transparent, white, and red. The sizes of the detected MPs were all in the range of 100~350 μm. The appearance of the MPs detected in the hepatopancreas tissues of Eriocheir sinensis crabs was similar to that in the bottom water, but the sizes were different. The appearance characteristics and chemical composition of MPs are closely related to their sources, and physical and chemical characterization can help for the tracing of MPs. The results of this study suggest that bottom water pollution may be a possible source of MPs in Eriocheir sinensis. The current risk of environmental MPs contamination during river crab farming in Hubei is low, and the risk of MPs contamination in Eriocheir sinensis is controllable.

For understanding the influence of different seasons and different types of natural wetlands on the efficiency of denitrification and the influencing factors,a first-order hydrodynamic model was constructed and an evaluation was made seasonally during 2019-2020 on the denitrification efficiency of two types of wetlands (i.e., artificially-enhanced natural wetland and ecologically-enhanced natural wetland) in Queshan reservoir. The results show tha: The denitrification rate constant (k) of the artificially-enhanced natural wetland [(0.285±0.170) m·d^-1] was higher than that of the ecologically-enhanced natural wetland [(0.144±0.143) m·d^-1] throughout the year. The concentration of nitrate in the Yellow River in non-flood season [(3.86±0.61) mg·L^-1] was significantly higher than that in flood season [(2.52±0.66) mg·L^-1]. For both of the two types of wetlands, the denitrification rate constant k in flood season was significantly higher than that in non-flood season (P <0.01). In non-flood season, temperature and dissolved oxygen also had significant impact on the performance of natural wetlands (P<0.05). However, in flood season, only dissolved oxygen contributed to the denitrification (P<0.05). As revealed in the results, by adopting alternatively mixed planting design in zones, the diversity and density of vegetation in artificially-enhanced natural wetland were increased, leading to higher denitrification efficiency. In the downstream of Yellow River, the concentration of nitrate and the denitrification efficiency of wetland have strong seasonal characteristics and the denitrification efficiency in flood season is relatively high. When the water diversion amount is 4×10⁵ m³·d^-1, the two types of wetlands can serve as buffer zones to support continuous and effective denitrification.

To solve the long existing obstacles of following season growth and other environmental risks caused by rice straw returning to the field, as well as the issue of local organic fertilizer supply deficit in water resource area, a series of batch tests on an integrated stainless-steel anaerobic digester (with total solids of 20%) were conducted. The characteristics of both biogas and residue production from the studied dry anaerobic digestion (AD) system with limited pig manure (PM) input (as nitrogen source) were investigated, to explore the biogas and digestate productivity from AD systems with high C/N ratio. Results show that the maximum gas yield was 4.7 L·d^-1 when C/N ratio reached 50∶1 (group C3). On the 12th day, the methane content in C3 group reached to 50% and biogas yield reached to 294 L·kg^-1, which were only 11.2% lower than the optimal group C6 (with C/N of 30∶1). It indicates that the upper limit of feedstock C/N ratio in dry AD system could be set at 50∶1. Moreover, the cellulose in C3~C6 (with C/N ratio of 50∶1~30∶1) could also be significantly degraded after digestion processes. The total nutrient in the dehydrated digestate of different treatments (C3~C6) was only around 2.25% to 3.71%, but other criteria such as organic matter content, pH value and heavy metal contents could all meet the organic fertilizer standards NY/T 525-2021 in agricultural industry, thus could be processed to high-quality organic fertilizer products. Based on engineering process simulation, when rice straw was processed at a rate of 12 t·d^-1, the annual profit of the studied system was 781 600 yuan, which is significantly higher than the profit of direct returning of straw to field. Therefore, it's considered both economically and environmentally feasible to apply biogas and fertilizer co-production from rice straw-based dry AD in water resource area.