Exploring the temporal and spatial patterns of taxonomic diversity can help ecologists to understand the interactions between biodiversity and ecosystems, and to formulate conservation strategies. In this paper, the spatial and temporal patterns of amphibians taxonomic diversity in the Badagongshan National Nature Reserve were investigated in 2018. In the study area, field surveys of amphibians were conducted in April, June, August and October, respectively, in 10 transects along an elevation gradient. The results show that the species composition and three taxonomic diversity indices (i.e., species richness, Shannon-Wiener index and Pielou evenness index) of the amphibian community were significantly different with the changes of seasons and elevations. Specifically, at the temporal scale, the dominant species were Leptobrachella liui and Amolops ricketti in April, Odorrana schmackeri in June, O. schmackeri and Odorrana margaretae in August, and Quasipaa boulengeri and A. ricketti in October. However, at the spatial scale the dominant species were O. schmackeri and A. ricketti at low-altitude transects, Leptobrachella liui and Pseudohynobius flavomaculatus at mid-altitude transects, Q. boulengeri, Leptobrachium boringii and Pseudorana sangzhiensis at high-altitude transects. In terms of the taxonomic diversity indices, values of the three indices were higher in June and August than those in April and October. While at the level of the whole year, there was no significant correlation between species richness and altitude. However, Shannon-Wiener index and Pielou evenness index showed significant hump-shaped responses with the increasing altitude. In different months, it was found that there were no significant correlations between taxonomic diversity indices and altitude (except the Shannon-Wiener index in June which showed a hump-shaped response with the increasing altitude). Overall, the study indicates that the taxonomic diversity of amphibians changes at both temporal and spatial scales. This can be attributed to various breeding cycles and hibernation cycles of amphibians, as well as their diverse temperature adaptation capabilities and habitat preferences.

Amphibians are sensitive to environmental perturbations and can be used as indicator species for biodiversity monitoring. In order to understand species composition, population, survival and threatened status, the spatial and temporal patterns of amphibian diversity in Damingshan National Nature Reserve of Guangxi were observed in April, June and August of 2016, 2017 and 2018, respectively. Ten line transects supplemented with PVC pipe refugia were monitored. In total, 18 species belonging to 5 families, 14 genera were observed, among which Odorrana nasuta, Gracixalus jinxiuensis, Theloderma rhododiscus were newly recorded in the reserve. The results show that species richness and individuals observed by different transects were slightly different. There were significant differences in species richness and Shannon-Wiener index in different months, but no significant difference in Pielou evenness index. However, there were no significant differences in species richness, Shannon-Wiener index and Pielou evenness index among different years. In addition, there were significant differences in species richness and Shannon-Wiener index between inside the reserve and outside the reserve, while Pielou evenness index showed no significant difference. The results of ANOVA show that species richness and Shannon-Wiener index were significantly different with different altitudes, while Pielou evenness index had no significant difference with different altitudes. There was no significant difference in species richness, Shannon-Wiener index, Pielou evenness index with different habitats. By three consecutive years of monitoring, it could be concluded that the amphibian species richness and individuals in Daming Mountain plots tended to be stable, which means that it has been well protected. The species richness and quantity of amphibians distributed in evergreen broad-leaved forest, herbaceous mirze and bamboo forest with relatively weak human disturbance are relatively uniform, while the number of amphibian species and Shannon-Wiener index in low-altitude mountainous areas and farmland are all higher.

Understanding the species richness and its spatial and temporal distribution pattern in certain region is of great significance for the protection of regional biodiversity. In order to master the species structure of amphibians as well as its dynamic changes of spatial and temporal distribution in the Nanyue Hengshan National Nature Reserve, Hunan, the amphibian resources status and the situation of habitat utilization in this region were investigated by line transect sampling in April, June and August 2018 respectively. A total of 15 species of amphibians were observed during the monitoring, which belongs to 12 genera, 6 families, 1 order. There were 11 species of amphibians belonging to nationally protected animal, accounted for 73.3% of the total 15 species in this survey. The results of this dynamic monitoring work show that the species diversity of amphibians had significant differences in time and space scale. In terms of inter-monthly biodiversity, the species diversity index was the highest in June. The species of amphibians observed in 4 different typical habitats were different significantly, in which farmland had the richest species diversity, followed by pond with 9 species, stream with 6 species and forest land with 3 species. The survival stress factors of amphibians in their habitats and distributional regions were analyzed and evaluated, and some suggestions for the protection and management of amphibians in this area have proposed.

In recent years, the number of threatened amphibians species have increased due to the rapid growth of the habitat loss, fragmentation and degradation. In order to clarify the current resources and habitat use of amphibians in Poyang Lake National Nature Reserve, and to make reasonable suggestions for the amphibian protection in the reserve, the line-transect method was used to determine amphibian species composition, number and diversity in April, June and August 2018. The results show that total of eight species which belonging to 1 order, 4 families were found in the reserve, including 1 national class Ⅱ protected species and 5 species that belong to state protected "beneficial or important economic or scientific valuable terrestrial wild animals". Hong Kong Rice-paddy Frog (Fejervarya multistriata) is the dominant species in the reserve (3 432 individuals which accounted for 64.93% of the total). There were no significant differences in amphibians species composition, quantity and diversity among different months, and there were significant differences in the amphibians quantity and Pielou evenness index among the three habitats. It could be concluded that amphibians have different distribution regions in the reserve due to their selectivity to habitat and difference of niche breadth. By this study the resource status and species diversity of amphibians in the reserve have basically been exploided, and on this basis, the threatened extrinsic factors on local amphibians have been analyzed, and reasonable suggestions for the protection and management to amphibians are put forward.

Based on the ozone monitoring date, the spatio-temporal variation of ozone concentration and its influencing factors of 35 cities in Northeast China from 2015 to 2018 were analyzed via spatial auto-correlation analysis and geographical detector. The results show that the interannual variation of ozone concentration increased from 2015 to 2018 and the monthly ozone concentration followed a pattern of inverted "V", which was higher in spring and summer and lower in autumn and winter. The high ozone concentration areas were mainly distributed in Liaoning Province and Jilin Province, which expanded to the north due to the effect of temperature. The ozone concentration had significant characteristics of agglomeration with hot spots distributed mainly in Liaoning Province. Meteorological factors and socio-economic factors all had significant effects on the distribution of ozone concentration. Temperature, the proportion of secondary industry and the ownership of civilian automobiles were all significantly correlated with ozone concentration.

This study investigated characteristics of air quality and environmental meteorological conditions during heating period in Handan City of Hebei Province using local environmental and meteorological data, and statistically forecasted mass concentrations of six pollutants with regression and back propagation (BP) neural network methods. The results show that the air quality index (AQI) of PM_2.5, PM₁₀, SO₂, CO (95) and NO₂ are highest in winter and lowest in summer, as opposed to the O₃-8(90) AQI. During heating period, local primary pollutants are PM_2.5 and PM₁₀, and the AQI of abovementioned pollutants are higher than the annual average except for O₃-8(90). Compared with no-heating period, during heating period precipitation amount and surface air temperature are lower, weak wind occurs more frequently, and local inversion temperature and static stability index are obviously higher. The worst environmental conditions occur in January and the worse time is early morning, especially in 5-7 am. The mass concentrations of primary pollutants are positively correlated with their individual mass concentrations, inversion temperature, dew point temperature and mixing layer height in the previous day, but negatively correlated with air temperature, wind speed, visibility and mixed layer height. The results further show that the skill on forecast of pollutant mass concentration with the BP neural network method is better than those with the linear regression method, and the BP neural network method can be applied to the air quality prediction in Handan City.

Ammonia volatilization from highland barley fields can contaminate the atmosphere and lead to the reduction of nitrogen use efficiency. Field trials were conducted to estimate the influences of different levels of nitrogen application on ammonia volatilization flux, NH₃ volatilization loss, nitrogen efficiency and grain yield in highland barley farmland ecosystem in Tibet. Results show that the yield of highland barley is significantly and positively correlated with nitrogen application (P<0.05). The contribution rate of nitrogen fertilizer was 32.13%, and the agronomic benefit of nitrogen fertilizer was 3.62-4.78 kg· kg^-1; The total accumulation of ammonia volatilization was 3.38-21.51 kg·hm^-2, The nitrogen loss rate caused by ammonia volatilization was 10.75%-15.49%, which increased significantly with the increase of nitrogen application (P<0.01); Ammonia volatilization mainly occurred in the basal fertilizer period, the ammonia volatilization stage of basal fertilizer was 44 days, and the volatilization peak appeared successively on the 10th day, and the ammonia volatilization of topdressing fertilizer was concentrated with 7days after fertilization. Comprehensively considering the production benefits and environmental safety based on ammonia volatilization, it is suggested that the application amount of pure N in this region is 40.02 kg·hm^-2 for base fertilizer, 13.32-26.70 kg·hm^-2 for top-dressing during knotting, 40.02 kg·hm^-2 for top-dressing during heading grain.

Identifying and optimizing the ecological security pattern is of great significance for ensuring regional ecological security and promoting sustainable development in the region. Using Jiaodong Peninsula as the study area, the preliminary ecological source area was identified through the ecological importance evaluation, and it was then further integrated into the ecological source area after verification of the fit with the nature reserve data. The luminous data were used to simulate the intensity of human activities to correct the ecological resistance surface obtained based on the value of different land types, and the minimum cumulative resistance model was applied to identify the ecological corridor and ecological buffer zone. The research results show that the land area of ecological sources on the Jiaodong Peninsula is 3 296.85 km², accounting for 10.78% of the total area of the study area. In addition to ecological sources, ecological buffer zones, ecological transition zones and development and construction zones account for 32.21%, 30.22% and 26.86%, respectively. 13 ecological corridors with a total length of 624.5 km have been identified. According to the natural geographic features and land use status of the study area, various components of the ecological security pattern in the region have been optimized and reorganized. Relying on natural water systems, hills and mountains, a layout system of networked ecological corridor groups with "one corridor, one belt, four zones and four groups" as the core has been proposed to realize a comprehensive, complex and networked ecological space structure in the Jiaodong Peninsula. This study can provide an important reference for advancing the regional integrated development and ecological space protection planning of the Jiaodong Peninsula.

To perform the ecological vulnerability assessment of Wutai Mountain Area,the "ecological sensitivity-ecological resilience-ecological stress" model was used with 11 comprehensively selected indicators. GIS technique, assisted by spatial principal component analysis, gravity center model, and differential analysis, were used to evaluate the ecological vulnerability of Wutai Mountain Area in 2000, 2005, 2010 and 2015. Furthermore, the temporal and spatial changes were analyzed along with the ecological vulnerability characteristics. The results show that: (1)The average ecological vulnerability index in Wutai Mountain from 2000 to 2015 was 4.83, described as moderately fragile. There were changes in area of each class, but the overall area was within mild and moderate vulnerability levels. Severe vulnerability was present in the north and northeast area. (2)From 2000 to 2015, the gravity center of ecological vulnerability index was within the Fanshi County, and the gravity center shifts were negligible. (3)Ecological vulnerability of three countries within Wutai Mountain Area was moderately fragile during 2000-2015. The Ecological vulnerability index of Fanshi County, Wutai County and Daixian County were in descending order. (4)The ecological vulnerability varied considerably for different land use types. The ecological vulnerability of cultivated land, unused land, urban and rural built up area was relatively high, within a moderately fragile level. Forest and grassland had relatively low ecological vulnerability index, within a mild vulnerability level. This paper aims to quantitatively assess the ecological vulnerability of the Wutai Mountain Area from 2000 to 2015. The results of the research would be helpful to the correctly understanding of the degree of ecological vulnerability in this region and comprehend its spatial differences for further management of eco-fragile areas, promotion of more efficient utilization of resources and maintaining the sustainable development of the ecosystem.

Due to coal mining in northern Peixian Courty, changes in topography, landforms, and land types have directly affected the ecological security of the entire region. An ecological security pattern needs to be constructed based on the evaluation of regional ecological security conditions. This study took the northern area of Peixian County as the research object, and selected the following eight indicators: elevation, slope, land cover type, vegetation cover, distance from water body, distance from road, distance from mine site, and distance from residential site. The spatial principal component analysis (SPCA) method was used to evaluate the ecological security status of the study area, and the minimum cumulative resistance (MCR) model was used to establish the ecological resistance surface. The GIS spatial analysis technology was used to extract ecological corridors and ecological nodes to construct the ecological security pattern of the study area. The results show that the level of ecological security in the study area is not high. The area with a moderate security level is 447.53 km², accounting for 44.53% of the total study area, and the area with a lower security level is 344.58 km², accounting for 34.28% of the total study area. 31 potential ecological corridors, 31 first-class ecological nodes, and 20 second-class ecological nodes were identified. Those corridors and nodes, together with the ecological source form the ecological security pattern of the study area, which provides a valid reference for ecological planning and ecological sustainable development in northern Peixian County.

The construction of ecological security pattern based on the "source-corridor" model is of great significance for improving regional ecological security. Nanchuan District, a typical desertification mountainous area, was taken as an example to construct the ecological security pattern. The core ecological source area was firstly identified based on the importance of ecosystem services, the eco-environmental sensitivity and the degree of inhabitants' ecological demands from ecological and human well-being perspective. The multi-factor comprehensive analysis method was then applied to detect the resistance surface of ecological source expansion using natural environmental factors, human interference factors and biological factors as evaluation indicators. Finally, the least cumulative resistance model and the hydrological analysis method were applied to identify the ecological corridors, so as to construct the regional ecological security pattern. It was found that the core ecological source area is dominated by forest with an area of 389.25 km², and the forest area decreases from the central to the north and the south in space. Six key corridors and a series of potential corridors were also successfully identified. In the key corridors, three of them traverse from west to east, and the others traverse from north to west. The potential corridors mainly distribute in hilly area with good environment, and form a network of regional species migration and energy circulation together with the key corridors. It is suggested that to construct an ecological network framework with one vertical and two horizonal ecological corridors to strengthen the regional ecological security pattern in Nanchuan District.

Temporal and spatial variation of mollusc community structures (i.e. species composition and taxonomic diversity) in the intertidal zone of Yellow River Delta were explored in four flow path of Yellow River to the sea in autumn of 2018 and spring of 2019. A total of 45 species of mollusc were collected and identified to be from 24 families and 11 orders in 2 classes. Among them, Littorina brevicula, Umbonium costatum, Batillaria cumingi, and Nassarius concinnusc were dominant species. The annual average density and average biomass of molluscs were 411.56 ind·m^-2 and 222.25 g·m^-2, respectively. At four flow path to the sea, the Margalef richness index (d) value ranged from 0.329 to 1.648, the Pielou index (J) value ranged from 0.302 to 0.678, and the Shannon-Wiener index (H') value ranged from 0.298 to 1.384. The variance analysis indicates that only average biomass had significant interactions between locations and seasons (P<0.05). The annual average density, average biomass, richness index and diversity index had extremely significant difference among different locations (P<0.01), and the seasonal difference was not significant (P>0.05). The spatial distribution of molluscs was significantly affected by the change of flow path of Yellow River to the sea, which had a certain relationship with the water and sediment discharge regulation and ecological water dispatching project. The molluscs, as the main food source of migratory water birds, are vitally important to the protection of water birds, so that their monitoring and protection should be strengthened.

Concrete and masonry stones were used to reinforce the riparian zone, which led to serious damage to the ecosystem of riparian in China. The ability of riparian to intercept and remove contaminants in runoff is basically lost, which intensified the eutrophication of rivers.In view of this common phenomenon in urban areas, the ecological mats were chosen to restore and transform the hard revetment in order to improve the effect of interception to contaminants. After the experiment of substrate screening, the combination of pelelith-ryegrass and coir-ryegrass with better growth was screened for the subsequent experiment. These two kinds of ecological mats had good effect of interception on TSS (>86%), and they were not affected by rainfall intensity and slope. In the simulated runoff experiment, TN and NH₄⁺-N removal efficiency of ecological mats decreased with the increase of slope, rainfall intensity and the time of rainfall.The removal rate of TN and NH₄⁺-N by coir ecological mats under 45° of slope and light rain was 51% and 73%, respectively, which is better than that of pelelith ecological mats(33% and 47%).With the increase of rainfall intensity and slope, the advantage of nitrogen removal by coir ecological mats was not obvious anymore. The removal rate of TP in simulated runoff by ecological mats was poor and fluctuates greatly. The technology of ecological mats has the advantages of low cost, easy to cultivate, fast laying and collection, so it is a feasible remediation technology for improving the effect of the revetment on the interception of contaminants.

Aquatic plants are not only natural bait and molting habitat for the crabs (Eriocheir sinensis), but also play an important role in purifying the water body of Chinese crab ponds. Elodea nuttallii, as the traditional plants in rearing ponds, usually performed poor growth or even death in hot summer, which lead to the deterioration of the crab habitat. Thus, screening candidate plants with high temperature resistance has great significance in ecological crab rearing. In this comparative study in high temperature period, three different aquatic plants, Ipomoea aquatic, Oryza sativa and Elodea nuttallii, were employed to assess their related effects on crab yields, water quality and greenhouse gas emissions for achieving stable yield as well as friendly environment for crab pond. The results show that there was no significant difference of crab yields in the three different treatments. Considering the amount of assimilated nitrogen or phosphorus, the three types of aquatic plants displayed as I. aquatic > E.nuttallii > O. sativa. Compared to E.nuttallii, O. sativa and I. aquatic treatments significantly reduced the water nitrogen concentrations from July to September whereas no significant difference was found for the phosphorus concentrations. Meanwhile, different aquatic plants changed CH₄ and N₂O emission fluxes. The accumulated CH₄ emissions of the O. sativa and I. aquatic treatments were both significantly higher than that of the E.nuttallii treatment, while no significant difference of accumulated N₂O emissions was found forthe three treatments. The E.nuttallii treatment had higher global warming potential (GWP) than the O. sativa and I. aquatic treatments. Considering the decay after grain-filling stage of O. sativa in late August, I. aquatic can be a great alternate of E.nuttallii in hot summer to improve water quality in crab rearing.

Wetland plants are one of the critical components of the constructed wetland, and wetland systems constructed by different plants have different nitrogen removal characteristics. In this study, three emerged plants, Canna indica, Pontederia cordata and Iris pseudacorus, were selected for the field control experiment under the hydraulic retention time of 7 days. The nitrogen removal characteristics of the three plants on treating swine wastewater were investigated. The results show that the removal rates of TN, NH₄⁺-N, and NO₃^--N were P. cordata > I. pseudacorus > C. indica, and the nitrogen removal loads were 3.93, 3.74 and 2.96 g·m^-2·d^-1, respectively. Among the wetland systems of the three emergent plants, microbial transformation was the most important way to the removing of nitrogen, accounting for 66%, 73%, and 64% of the total nitrogen removal amount, respectively, and the amount of sediment adsorption (13%, 10%, and 22%) and plant uptake (21%, 17%, and 14%) were lower. P. cordata had the largest biomass, the best growth and nitrogen removal rate and was suitable to be the pioneer plant for swine wastewater treatment. The root system of I. pseudacorus was the most developed, and it grew well under low temperature conditions, which can be a seasonal complement to P. cordata. C. indica can grow well in the swine wastewater, but its purification capacity was weak.

Incubation experiment was conducted to study the effects of different organic material additions on the inorganic nitrogen conversion in coastal saline-alkali soil, including seven treatments: CK(control), N (N fertilizer, ammonium sulfate), N+B (N fertilizer with biochar), N+M (N fertilizer with chicken manure), N+S (N fertilizer with straw), N+BM (N fertilizer with biochar, and chicken manure), N+SM (N fertilizer with straw, and chicken manure). The results show that, N fertilizer promoted the occurrence of nitrification and mineralization, increased soil ammonium throughout the incubation period. Compared with the N treatment, the N+B treatment held a certain amount of ammonium nitrogen, delayed the conversion of ammonium nitrogen to nitrate nitrogen, with its ammonium nitrogen content to be 1.85 times as that of N treatment, and inhibited soil nitrogen mineralization and nitrification, while decreased soil nitrate and mineral nitrogen by 24.77% and 55.86%, respectively. The N+M treatment promoted soil nitrification and mineralization, reduced soil ammonium by 29.79%, and finally increased soil nitrate and mineral nitrogen by 24.32% and 73.19%, respectively. The N+SM treatment had a similar effect as the N+M treatment, which increased soil nitrate and mineral nitrogen by10.33% and 35.01%, but having no significant influence on soil ammonium. The N+S and N+BM treatments had no significant effect on soil nitrification and mineralization. Therefore, for the comprehensive improvement and utilization of coastal saline-alkali soil, the addition of chicken manure can increase the content of mineral nitrogen and provide more nitrogen for plant growth, but it can promote soil nitrification and increase the content of nitrate nitrogen in the soil, bring about increased N₂O emissions and the risk of nitrate pollution of groundwater; while biochar has the effect of inhibiting soil nitrification and mineralization, it can hold more ammonium nitrogen and delay the nitrification of ammonium nitrogen, and reduce the loss of organic nitrogen. Biochar is an excellent organic material additive for saline soil reclamation.