Ecosystem service flow is an effective way to explore the supply and demand of ecosystem services. It has played an important role not only in revealing the dynamic process of the flow of ecosystem services from natural ecosystems to human society, but also in clarifying the quality, direction and distribution characteristics of ecosystem services. From the perspective of connotation, theoretical framework, model and application of ecosystem service flow, this study systematically reviewed the research progress of ecosystem service flow, based on the selected 183 SCI papers and 33 domestic core journal papers by using CiteSpace visualization software. The applicability and applications research of relevant models and methods have been summarized, and the shortcomings of existing studies and future research directions are discussed. The results show that there have been some important progresses on the study of ecosystem service flow, mainly including the concept discussion of service flow, model applications, quantification of service flow, ecosystem service supply and demand assessment, ecological compensation, ecological restoration, and security pattern optimization. While there are much less progress on researches of general framework exploration, assessment model, index system selection and multi-scale study. In the future, it is necessary to strengthen the studies on the application of ecosystem service flow in ecological protection and policy design, the establishment of a general research framework of ecosystem service flow. The development and calibration of models, the study on ecosystem service flow in key regions with multi-temporal scales, the optimization of ecological security pattern, ecological compensation and ecological restoration, so as to provide important scientific basis for the formulation of regional ecological protection and management policies.

Microplastics, which pose a great threat to aquatic life and human health are widely distributed and existed for a long time in the water environment. As primary producers, microalgae are extremely sensitive to the toxic pollutants and can be utilized by high-trophic organisms, so they have been applied to assess the ecotoxicity of microplastics. In order to understand the current research status of the interaction between microplastics and microalgae, the related published papers of the interaction between microplastics and microalgae have been searched from Web of Science (WOS) from January 1, 2002 to May 31, 2022. Tools such as CiteSpace and VOSviewer have been used to visually analyze the authors, institutions and keywords from the 485 literatures, and to explore the research hotspots and research context. The bibliometric analysis results show that the research on the interaction between microplastics and microalgae is an emerging research direction in the field of ecotoxicology. Environmental Pollution (66 articles) and Science of the Total Environment (56 articles) are the two most published academic journals in the field. China has a strong interest in this field, and the number of publications is far higher than those of other countries. In addition, there is close cooperation among domestic institutions such as Tsinghua University, Ocean University of China and Chinese Academy of Sciences. Existing studies are focused on the ecotoxicity effects of microplastics on microalgae and the mechanism of toxicity, which are mainly evaluated from the dimensions and concentrations of microplastics, environmental impacts and other factors. A total of 18 microplastics and 28 microalgae species are involved, and Chlorella sp. is the most studied, followed by Chlamydomonas sp., Dunaliella sp. and Phaeodactyla sp. Potential toxicity, combined effects and trophic levels are the three research hotspots in this field. Microplastics can form composite pollutants with other contaminants in different ways and produce combined toxic effects, and the ecotoxicity and bioaccumulation effects of composite pollutants on microalgae, as well as their migration, transformation and potential toxicity in food chains are emerging trends in this field.

Aiming at the non uniqueness of feature vector direction of remote sensing ecological index(RSEI) model and the existence of necrotic pixels in optical images, 489 Landsat TM/SR availability remote sensing images of Qilian Mountain National Nature Reserve from 1986 to 2021 were selected in view of Google Earth Engine platform, and the improved remote sensing ecological index model was utilized to assess the ecological environment quality of the reserve. The single factor analysis and interactive detection analysis in geographical detector were applied to analyze the mechanisms of the seven influencing factors (NDVI, WET, LST, NDBSI, land use type, DEM, and population density) of RSEI. The results show that:(1) Compared with remote sensing ecological index model, the improved remote sensing ecological index model avoided the interference of feature vector direction, and could better reflect the changes of ecological environment quality. The ecological environment quality from 1986 to 2021 demonstrated a recovery trend of "first decreasing and then increasing", with a spatial distribution of "high in the east and low in the west". (2)The spatio-temporal differences in the reserve indicate that the ecological environment quality slightly deteriorated, unchanged or slightly improved in the past 35 years. The distribution of slightly deteriorated areas located mainly in the northern part of Sunan Yugur Autonomous County in Zhangye City and the junction of Zhangye City and Wuwei City. The slightly improved areas were scattered in the reserve, while the core areas were relatively more distributed in the reserve. (3) From the analysis of the causes of ecological environment quality, among the seven influencing factors, greenness (NDVI) had the strongest explanatory power on the spatial differentiation characteristics of RSEI. Considering the synergistic effect of multiple factors, the NDVI and NDBSI were the key driving indicators of ecological environment quality. The results above show that the ecological environment quality in Qilian Mountain Nature Reserve has been gradually improved in recent years, and a series of environment protection measures were effective.

Regional ecological security is the direction of the development of modern cities. Understanding of regional ecological risks and building an ecological security pattern can contribute to the comprehensive improvement of the level of regional ecological security. To date, the study of regional ecological risks are mainly focused on humid and subhumid zones, and the driving factor analysis of regional ecological risks are mainly using geographical detectors, and the research method is relatively single. In this study, Kuye River Basin was taken as the research object, and the land-use database in 2000, 2010, 2013 and 2020 were used as the basic data source, and an ecological risk assessment model was constructed from the perspective of landscape ecology, and the ecological risk of the basin was quantitatively studied by using spatial and temporal evolution patterns coupled with distribution characteristics and driving factors. The results show that:(1) the ecological risk of the river basin is divided into three levels:high, medium and low. The proportion of high-risk areas in the entire study period is the largest, accounting for more than 40% of the area;(2) During the period from 2000 to 2020, the proportion of high ecological risk areas decreased slightly from 45.95% to 44.98%, and the high risk area decreased by approximately 84.806 km²; (3) The ecological risk in the basin presents a certain degree of spatial differentiation characteristics of high-high aggregation (Moran's I=0.333), and the high-risk areas are concentrated in the center of the basin, basically distributed along the water system in the basin, and the farther the distance from the water system, the lower the ecological risk index; (4) Precipitation, vegetation coverage and temperature are the main natural factors that affecting ecological risk in the basin, and the direct path coefficients are -0.479, -0.449 and 0.383, respectively. In addition, GDP is also the main indirect factor affecting ecological risk in the region, and the total effect coefficient is -0.49.

Conservation tillage is the important initiative to guarantee national food security and realize the strategy of "Storing Grain in Land and Technology". Based on the micro-survey of 427 grain-growing farmers in the suitable area of conservation tillage, the compensation standard of conservation tillage was measured by using the contingent valuation method and the constructed equivalent utility function, then the factors affecting farmers' willingness to accept was analyzed with the binary Logistic model. The results show:(1) The compensation standard for conservation tillage calculated by the contingent valuation method is 735.98 yuan·hm^-2, and the one after being corrected by the equivalent utility function is 410.07 yuan·hm^-2, with a significant difference between them. (2) The farmers' willingness to accept measured by the contingent valuation method tends to be higher, and after considering the influence of the individual farmers and socio-economic characteristics, the farmers' willingness to accept measured by the equivalent utility function is more appropriate to the reality, thus, it could be considered as the minimum compensation standard for implementing conservation tillage in the sample areas. (3) The farmers' willingness to accept in the main grain-producing areas measured by both methods is higher than the overall willingness of farmers in the sample areas. Therefore, the emphasis of carrying out conservation tillage compensation should be concentrated on the main grain-producing areas. (4) The overall sample of farmers' willingness to accept is affected by the individual characteristics and cognitive characteristics of farmers. In addition to the above factors, the farmers' willingness to accept is significantly affected by the number of agricultural laborers and aggregate household income in the main grain-producing areas. The findings of the study have theoretical and practical contribution for local governments to scientifically formulate conservation tillage compensation standards and promote farmers to carry out conservation tillage.

Accurately evaluating the impact and mechanism of ecological environmental protection on residents' livelihoods is of great significance for solving the conflicts between protection and development. Based on the sustainable livelihood model, this paper constructs the analysis framework of farmers' livelihood outcomes from the background of wetland conservation. Questionnaire survey data of farmers in the Dashanbao Black-necked Crane Nature Reserve in Yunnan Province were collected to estimate the influence mechanism of wetland conservation on rural households' livelihood outcomes by using the Structural Equation Model based on the partial differential least squares method. According to the results, participation in wetland conservation has a direct and negative impact on households' income, but a positive and indirect effect through the chain of "wetland conservation-livelihood capital-livelihood strategy-household income". Comparatively, the indirect effect is lower than the direct effect. Therefore, the total effect is significantly negative. Moreover, participation in wetland conservation has a direct and positive impact on households' poverty alleviation and subjective well-being, and a positive and indirect effect through the chain of "wetland conservation-livelihood capital-livelihood strategy-poverty alleviation/subjective well-being". Therefore, the total effect is significantly positive. Compared with samples partially participating in wetland restoration, the impact of wetland conservation on the livelihood outcomes is more obvious in samples returning all farmland to wetland. Based on the findings, this study proposes the following three practical suggestions regarding farmers' livelihood selection and regional sustainable development. Firstly, policymakers should promote the combination of wetland conservation policy and the livelihood development of local residents, and effectively increase the accumulation of their livelihood capital. Secondly, decision-makers should actively promote economic forest planting and ecological livestock breeding to achieve intensive development and agricultural transformation. Finally, the government should plan and develop eco-tourism, encourage migrant working, introduce ecological, pension, and other industrial models, call on young people to return to their hometown for entrepreneurial activities to provide a variety of employment opportunities for the local farmers, and promote the diversification of their livelihood strategies.

Studying population spatial patterns is an effective way to deeply understand the functions and processes of population ecology. Assessing the spatial distribution patterns of dominant populations in forest communities provides reference data to elucidate the ecological characteristics of the population and the trend of community succession. The subject of our research was a Quercus mongolica population on the southern slopes of four old volcanoes in Wudalianchi. The Q. mongolica population was divided into different age classes and non-age classes. To assess the spatial distribution characteristics of the different classes on different spatial scales, the Q. mongolica data for the four volcanoes were analyzed by a multi-scale and multi-index comprehensive judgment method. The main findings are as follows. (1) The spatial distribution of Q. mongolica classes varied with spatial scale at the four volcanoes. The age-disaggregated classes were mainly clustered at the 200-m² and 400-m² scales, but the intensity of clustering was significantly different. The cluster distribution of age-class Ⅴ was significantly different at the 25-m² and 50-m² scales, whereas that of age-class Ⅶ was significantly different at scales of 200-m² and 400-m². (2) The spatial distribution pattern of Q. mongolica classes exhibited obvious scale effects in the four volcanoes. The six discriminant indexes showed different trends with increasing scale. The power increase was greatest for the age-disaggregated classes (46%), and the maximum power increase was 50% for age-class Ⅶ. (3) The size of sub-populations of Q. mongolica differed among the four volcanoes. In the age-disaggregated classes, only the mean square value of East Jiaodebu Volcano was extremely significant at the 200-m² scale, and the population size was 200 m². In the age-class V, only the mean square value of South Gelaqiu Volcano was significant at the scale of 400 m², and the population size was 400 m². For both age-class Ⅵ and age-class Ⅶ, only the mean square value of East Jiaodebu Volcano was significant at the 400-m² scale, and the pattern scale was 400 m². In this study, factors such as the spatial scale, age class structure, and stage of community succession, as well as the interactions between and cumulative effects of these factors, may be the main reasons for the significant differences in the spatial patterns within the studied Q. mongolica population. The population pattern scale should be further studied.

Identifying critical areas for ecological protection and restoration and forming different remediation and restoration strategies are required for ecological protection and restoration in territorial space. However, the relationship between natural ecosystems and socioeconomic systems was seldom considered in identifying the critical areas. And the ecological risks were seldom investigated. In this study, based on ecosystem services' protection and restoration needs, a research framework for ecological protection and restoration of territorial space was established with a "trouble-risk" cognitive system. Primary ecosystem services in a typical rapid urbanization area were first evaluated by using the InVEST model, including habitat maintenance, water resource conservation, soil and water conservation, carbon sequestration and oxygen release. The critical areas that requiring protection and the degradation areas that needing remediation were then identified. The degradation risk areas of the ecosystem services were determined by using the landscape ecological risk assessment method. Finally, a comprehensive pattern has been established and a strategy for territorial space ecological protection and restoration in the area is proposed. The conclusions of the study are:(1) The spatial distributions of ecosystem services in the study area were significantly different, and some regions showed significant degradation. (2) The degradation risk of ecosystem service during the study period (2019) was generally low, with which, 7.38% accounted as relatively high-risk and high-risk areas, 38.14% as low-risk areas, and 53.45% as relatively lower-risk areas. (3) Based on the pattern of ecological protection and restoration in the territorial space, differentiated strategies are proposed, including improving the existing reserve planning system, paying attention to the ecological restoration of the cultivated land landscape on the south side of Qishan Forest Park, and strengthening the risk control of river landscapes.

Artificial intelligence (AI) recognition of camera traps images has become one of the hot spots in the interdisciplinary research of ecology and AI. In order to explore the accuracy and influencing factors of artificial intelligence recognition of infrared camera animal images, the differences between artificial intelligence recognition and artificial recognition were compared. Taking the monitoring of macaques (Macaca mulatta) on Dajinshan Island in Shanghai as an example, the TOLO v3 model was applied for training and testing, and the feasibility of the TOLO v3 model to recognize a large number of infrared camera images was discussed. Meanwhile, the accuracy and recognition efficiency of AI image recognition and artificial recognition are compared to find out the optimal solution of recognition method under specific sample capacity. The recognition results of 11 106 photos show that the total recognition accuracy of artificial intelligence is 69.0%, and the average is 68.2%. The total accuracy of artificial recognition was 99.0%, and the average was 99.1%. The accuracy of artificial recognition was significantly higher than that of artificial intelligence (t=-9.256, df=22, P<0.01). The recognition accuracy of simple habitat background was significantly higher than that of complex habitat background (Z=-2.270, P=0.023). For artificial recognition, there was no significant difference in accuracy between simple habitat background and complex habitat background (Z=-0.406, P=0.685). AI recognition can be used for infrared images with a single habitat and background, but should be cautiously used for background recognition of complex habitats. In addition, AI recognition can be used for initial screening of large numbers of photographs. Artificial recognition can be used to identify photos with complex habitat backgrounds and to review photos after initial screening by artificial intelligence. For the sample size of ten thousand photos, artificial intelligence does not show obvious time advantage, but artificial recognition has an advantage of accuracy. With the continuous establishment and open application of various training data sets, artificial intelligence recognition for large vertebrates, especially for some well-known star species, may take the lead in replacing artificial recognition.

The second national pollution source survey show that agricultural non-point source pollution (ANP) has become one of the main causes of water environment deterioration in Guangdong Province. Therefore, it is important to clarify the ANP status in the province for the prevention and control of water pollution and for rural revitalization. The improved export coefficient method was used to analyze the annual ANP loads and its spatial and temporal variation characteristics in Guangdong Province from 2009 to 2019. On this basis, the seasonal and monthly pollution loads of ANP in the province were evaluated with consideration of monthly differences in fertilizer application, precipitation, livestock and aquaculture. The impact of ANP on the water environment was evaluated by unit area load coefficient method, and the main sources of ANP were explored. The results indicate that:(1) from 2009 to 2019, the total nitrogen load in Guangdong Province showed a decreasing trend and the total phosphorus load showed a rising trend with spring and summer being the peak seasons of pollution discharge in a year, and the total nitrogen and phosphorus discharge from April to October accounting for 68.8% and 67.2% of the annual load, respectively. (2) The total nitrogen load trended decreasing in 76.2% of the cities and the total phosphorus load trended increasing in 61.9% of the cities, and compared to 2009, the total nitrogen load in 71.4% of the cities decreased the threat to the environment and the total phosphorus load in 52.4% of the cities enhanced the threat to the environment in 2019. (3) In general, the environmental damage caused by agricultural nitrogen and phosphorus loads in western Guangdong was more serious than that in Pearl River Delta, and in northern and eastern Guangdong. (4) The contribution rate of each pollution source to nitrogen and phosphorus pollution loads from high to low is livestock and poultry breeding, crop farming and aquaculture. The evaluation results of the current situation and change characteristics of ANP in the province are of great significance to the prevention and control of ANP and the construction of beautiful countryside in the province.

To investigate the spatiotemporal distribution characteristics and influencing factors of microplastics in freshwater wetland systems, water and sediment sampling were conducted at 10 locations within the Huixian wetland basin, a representative Karst wetland, during both wet and dry seasons. The findings revealed that the abundance of microplastics in the Huixian wetland ranged from 5 466.7 to 24 333.3 n·m^-3(water) and 3 380.0 to 14 533.3 n·kg^-1(sediment) during the wet season. In the dry season, the range was 12 713.3 to 34 906.7 n·m^-3(water) and 11 866.7 to 42 486.7 n·kg^-1(sediment). Significant spatial and temporal differences were observed in the distribution characteristics of microplastics abundance (P<0.05). The dominant shapes of microplastics in the Huixian wetland were fibers, films, fragments, and pellets. Fibers were primarily found in water, while fragments were more prevalent in sediments. Microplastics with small particle sizes (0.45 μm to 0.5 mm) were predominant in both water and sediments during both wet and dry seasons. The abundance of microplastics decreased with the increasing of particle size. The identified polymer components were mainly polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), and polyethylene (PE). PE was the predominant polymer type in water, while PET dominated in sediments. The abundance of microplastics in the wet season was significantly lower than that in the dry season, likely attributed to the dilution effect caused by rising water levels. Moreover, the dry season exhibited higher proportions of microplastics with small particle sizes (0.45 μm to 0.5 mm) and a higher proportion of PE among the polymer types. In terms of spatial distribution, areas such as tourist sites, concentrated fishery and agricultural zones, and vicinity of villages displayed higher microplastics abundance compared to other areas. The main sources of microplastics in the Huixian wetland include rural domestic sewage discharge, fish farming, agricultural activities, and tourism.

The impact of reservoir operation on water environment within the reservoir area is a hot topic for watershed ecological protection, especially for the near-dam section environment which directly affects the the downstream ecological environmental. In this study, a field monitoring of hydrology and water quality was conducted simultaneously in the near-dam section of the Shuikou Reservoir, to reveal the spatial distributions of key water quality physicochemical indexes and the main influencing factors under the condition of guaranteed 50% flow discharge rate. The observational results suggested a typical horizontal and vertical circulation pattern in the area, because the average near-dam rates of flow were measured as 1 420 and 1 440 m³·s^-1, respectively, while the rates of discharge from the dam were comparably lower with 1 227 and 1 207 m³·s^-1, respectively. The spatial distributions of the physical and chemical water quality indicators were primarily affected by both vertical and horizontal circulations in the reservoir area. The study area was featured with excessive TN, severe hypoxia in the middle and bottom layers, and excessive TP in the surface and bottom layers. The S3 section, located at 5.5 km upstream of the Shuikou Dam, was particularly eutrophic at the bottom. The distribution of water quality physicochemical indexes in the near-dam area was mainly affected by water temperature and blue-green algae abundance.

The intestinal contents from the foregut, midgut and hindgut of earthworms (Eisenia fetida) were collected under initial-starvation-cow dung continuous culture conditions, and the 16S rRNA gene amplicon sequencing was consequently conducted to investigate the segmental differentiation of gut bacterial communities and their responses to starvation and feeding. The results show that the bacterial community diversity and composition were similar between adjacent intestinal segments; the community similarity between midgut and hindgut segments was higher than that between foregut and midgut segments, and the differences were greater between separated gut segments (foregut vs. hindgut). The dominant bacterial phyla across all earthworm gut segments were Firmicutes (14%-55%), Actinobacteria (16%-39%), and Proteobacteria (15%-37%). The changing trends of dominant bacteria along with the gut transmission (foregut-midgut-hindgut) were inconsistent under different culture conditions. The core ASVs of the foregut, midgut and hindgut segments mainly belonged to Firmicutes (35%-48%), Actinobacteria (20%-26%), and gamma-Proteobacteria (14%-16%). The foregut and hindgut segments had unique core ASVs, which mainly belonged to delta-Proteobacteria (7%) and Fibrobacteres (6%), respectively. From initial state to starvation state, the Shannon diversity index of gut microbiota decreased significantly (P<0.05), while the Sobs richness index decreased insignificantly (P>0.05); the relative abundances of alpha-/delta-Proteobacteria and Actinobacteria decreased significantly (P<0.05), while that of gamma-Proteobacteria, Firmicutes and Bacteroidetes increased significantly (P<0.05). From starvation state to cow dung culture state, the Shannon diversity index and Sobs richness index further significantly decreased (P<0.05). The relative abundance of delta-Proteobacteria and Firmicutes increased significantly (P<0.05), while that of gamma-/alpha-Proteobacteria and Actinobacteria significantly decreased (P<0.05), and that of Bacteroidetes had no significant change (P>0.05). The cluster analysis results show that the gut microbiota of earthworms was stable to a certain extent. Combining the results of bacterial community structure and differential ASVs analysis, it was shown that starvation-cow dung culture changed the gut bacterial community of earthworms, with starvation mainly changing the bacterial community abundance, while cow dung culture changing both the bacterial community abundance and composition. Taken together, the intestinal microbial community of earthworms had obvious intestinal segment differentiation, which can resist disturbance and maintain stability to a certain extent. The earthworm gut microbial community displayed a clear response to both starvation and feeding, with a stronger response to feeding.