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Formation mechanisms of iron-manganese nodules in soils from high geological background area of central Guangxi. JI Wen-bing, YANG Zhong-fang, YIN Ai-jing, LU Yuan-yuan, YING Rong-rong, YANG Qiong, LIU Xu, LI Bo, DUAN Yi-ren, WANG Jue, WANG Yi-zheng, YU Tao, WU Tian-sheng, ZHANG Qi-zuan Chinese Journal of Ecology    2021, 40 (8): 2302-2314.   DOI: 10.13292/j.1000-4890.202108.006 Abstract （876）      PDF（pc） （10810KB）（243）       Knowledge map    Save Iron-manganese nodules are widely distributed in karst soil with high geological background, the content of which is much higher than that in nonkarst soils. To better understand the formation mechanism of iron-manganese nodules in karst soil, the nodules in the soil (0-20 cm) of central area of Guangxi were collected. The formation process of iron-manganese nodules in the soil of high geological background area was examined via the optical microscope (OP), field emission scanning electron microscope (FESEM), and energy spectrum analysis (EDS), combined with the complex soil forming process in karst area. The results showed that there were two kinds of nodules in the karst soil, i.e., iron nodules and manganese nodules. Generally, the nodules were sub-circular to elliptical in shape, and the particle size ranged from 0.5 to 4.0 mm. There were two kinds of iron-manganese nodules, with or without banded structure. Manganese nodules were mainly composed of iron oxides and manganese oxides, while iron oxides were mainly distributed in iron nodules. Based on those findings and the process of karst soil formation, the formation process of iron and manganese nodules in high geological background soil is summarized: (1) in the process of soil formation in karst area, iron and manganese were aggregated in different levels, which provides rich material sources for the formation of nodules; (2) the seasonal dry-wet cycling climate conditions led to the alternation precipitation of iron and manganese, which enhanced the formation of nodules; (3) the micropore structure in the nodules can provide space for microbial activities and channels for material flow, the special climate and environmental conditions rich in organic matters and microorganisms accelerate the formation of iron-manganese nodules, and eventually form iron-manganese nodules that are widely deve loped in karst soils. Related Articles | Metrics | Comments（0）

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The application of structural equation modeling in ecology based on R. SHI Ya-Fei, SHI Shan-Heng, HUANG Xiao-Min Chinese Journal of Ecology    2022, 41 (5): 1015-1023.   DOI: 10.13292/j.1000-4890.202203.016 Abstract （744）      PDF（pc） （2621KB）（942）       Knowledge map    Save Structural equation modeling (SEM) is a major approach for analyzing ecological data. Differing from other multivariate statistical methods, SEM is mainly driven by assumptions and could quantify both direct and indirect causal relationships among multi-variables. Since the introduction of SEM into the field of ecology in China is relatively short, scientists encounter many problems when using SEM, with various mistakes. Therefore, we elaborated principles, processes, evaluation and modification of SEM in this review. With a case study, we introduced the usage of two major R packages for SEM, i.e. lavaan and piecewiseSEM. Concretely, lavaancan perform SEM with latent variables, while piecewiseSEM can incorporate nonindependent observations, and handle response variables with residuals not satisfying multivariate normal distribution. This review can help researchers understand and use SEM correctly and accurately, and promote the usage of SEM in ecology. Related Articles | Metrics | Comments（0）

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Dust retention capacity and dust particle size of 20 commonly used greening tree species. YAN Qian, XU Li-shuai, DUAN Yong-hong, PAN Li-chao, LIU Li-wen, YANG Yu-ying Chinese Journal of Ecology    2021, 40 (10): 3259-3267.   DOI: 10.13292/j.1000-4890.202110.027 Abstract （694）      PDF（pc） （1910KB）（93）       Knowledge map    Save Based on analyses of leaf surface dust retention and retained dust particle size of 20 commonly used greening tree species in natural environment, and comparison with atmospheric dust, we analyzed the difference in dust retention capacity and particle size of different species, and examined the effects of leaf morphology and leaf surface microstructure on the mechanical composition of retained dust. There were significant differences in dust retention capacities of the 20 species. Euonymus japonicus showed the highest dust retention capacity of 1.75 g·m-2, while Viburnum opulus subsp. calvescens showed the lowest value of 0.40 g·m-2, being 4.4 times less than that of E. japonicus. The distribution curves of particle size of retained dust on leaf surfaces of 20 species were classified into three categories: two-peak distribution, three-peak distribution, and four-peak distribution. The particle size of atmospheric dust in the same period showed a three-peak distribution. The difference in particle size between atmospheric dust and retained dust by the 20 tree species indicates that leaves had a selective retention effect on atmospheric dust. The leaves of different tree species had different retention capacities for particles of differentsizes, and the volumetric content of PM>10 from foliage dust was the largest. The blades with grooves were more conducive to the retention of PM2.5, while the leaves with protruding structures were more conducive to the retention of PM>10. Blades with rough microstructures, such as fluff, grooves, and protrusions, had strong dust retention capacity. Our results can guide the selection of suitable greening tree species for different pollution sources, alleviating air pollution, and improving air quality. Related Articles | Metrics | Comments（0）

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Research advances in carbon use efficiency  at multiple scales. DI Yang-ping, ZENG Hui, ZHANG Yang-jian, CHEN Ning, CONG Nan Chinese Journal of Ecology    2021, 40 (6): 1849-1860.   DOI: 10.13292/j.1000-4890.202106.012 Abstract （665）      PDF（pc） （1302KB）（229）       Knowledge map    Save Carbon use efficiency (CUE) is defined as the proportion of carbon (C) received from the environment that is used for growth. As one of the key indicators for the ability of biological carbon sequestration, it is widely implemented in the carbon cycle and process-based models. Research on CUE is carried out by various methods at multiple scales. However, the results of different methods vary greatly because of the scale-dependence of CUE, which makes the results difficult to integrate, becoming a vital factor restricting the research methods and application of CUE. In this review, we classified the common CUE acquisition methods into plot-scale, ecosystem-scale, landscape & regional scale and continental & global scale. We summarized the characteristics, advantages and limitations of each method. The progress of CUE application in research is reviewed at each scale. It is found that CUE is influenced by biotic and abiotic factors, which control CUE at different spatial and temporal scales. Moreover, the value of CUE varies with methods and scales applied in study. In order to deepen the understanding of CUE, future research should comprehensively consider the interactive effects of biological and environmental factors, improve the accuracy of data measurement, and promote model optimization by integrating multi-scale results. Related Articles | Metrics | Comments（0）

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Views on distinguishing the concepts of rangeland and grassland and proposing proper use of their terminology. DONG Shi-kui Chinese Journal of Ecology    2022, 41 (5): 992-1000.   DOI: 10.13292/j.1000-4890.202205.001 Abstract （551）      PDF（pc） （834KB）（216）       Knowledge map    Save Rangeland and grassland are two key terms used in multiple disciplines and departments. However, there are confusion, overlap and crisscross in the use of these two terms due to their chaotic connotation and denotation defined by various disciplines and departments. In order to clarify the connotation and denotation of rangeland and grassland in different contexts of disciplines and departments, and to enhance their proper use in practice, I collected diverse and rich references and information in rangeland and grassland terminology, summarized the connotation and denotation of rangeland and grassland defined in various countries and disciplines, clarified the terminology changes of rangeland and grassland across different time and disciplines. Finally, I proposed proper use of those two terms to mitigate the confusion, overlap and crisscross and to provide a scientific basis for rational protection and utilization of grassland resource and ecosystems. The conclusions are based on the comprehensive analysis. There are broad and narrow definitions of rangeland and grassland. The broad definitions are derived from the international subjects of agriculture and vegetation as well as national subjects of agriculture and law, in which rangeland and grassland can be regarded as the synonym referring to the landbiology resources with multiple functions and production base for pratacultural industry, where herbaceous species dominate the vegetation with some shrubs and sparse trees used as the habitats or foods for livestock and wildlife, as well as good living environments and biological products for the human beings. These terms have been generally used as “rangeland” or “grassland” in the official documents of forestry, grassland, and agriculture departments, foreign and domestic literatures, textbooks, courses, etc. The narrow definitions are derived from the national subjects of vegetation science and land types. In the subject of vegetation science, it is defined as the zonal vegetation distributed in semiarid and semihumid areas with the perennial xerophytes as dominant plants (occasionally with some small subshrubs) in the community. The term is normally applied for vegetation classification and should be generally used as “steppe or grassland vegetation” (e.g., temperate grassland vegetation or steppe vegetation). In the subject of land types, it is defined as one of the land use types, dominated by herbaceous species. This term is normally used for land use classification by land resource (natural resources) department and should be generally used as “land type of grassland”. Related Articles | Metrics | Comments（0）

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Eco-environmental quality assessment and cause analysis of Qilian Mountain National Park based on GEE. ZHANG Hua, SONG Jin-yue, LI Ming, HAN Wu-hong Chinese Journal of Ecology    2021, 40 (6): 1883-1894.   DOI: 10.13292/j.1000-4890.202106.034 Abstract （500）      PDF（pc） （2948KB）（321）       Knowledge map    Save The ecoenvironment is highly related to human life. Remote sensing technique can objectively and quantitatively evaluate the spatial and temporal variations of ecoenvironment quality and thus provide a scientific basis for regional eco-environment management. Based on the Google Earth Engine (GEE) platform, we adopted Landsat TM/OLI remote sensing images as the basic data source to calculate the remote sensing ecological index (RSEI) that reflects the ecoenvironment quality. Using RSEI, we evaluated the eco-environmental quality of Qilian Mountain National Park during 1989-2019 and analyzed the reasons. The results showed that RSEI performed well in assessing the eco-environment quality of Qilian Mountain National Park. Greenness and wetness were the two indices with positive effects on the eco-environment quality, while dryness and heat indices had adverse effects. The analysis of spatial and temporal variations in Qilian Mountain National Park showed that the eco-environment quality presented a trend of “slow decline  rapid decline  increase” during 1989-2019. Changes in eco-environment quality were stable from 1989 to 1999, mainly mildly deteriorated from 1999 to 2009, and mainly mildly improved from 2009 to 2019. The analysis of the causes of eco-environment quality showed that the effects of all the four indices were significant. The strength of natural factors in influencing ecoenvironment quality were in order of greenness > dryness > wetness > heat in 1989; heat > greenness > wetness > dryness in 1999; dryness > heat > wetness > greenness in 2009; and greenness > wetness > dryness > heat in 2019. Animal husbandry was an important factor affecting the eco-environment quality of Qilian Mountains National Park. Our results suggested that the GEEbased platform could be used as a computing platform to evaluate the eco-environment quality of Qilian Mountain National Park. This platform extends the application of RSEI in the evaluation of eco-environment quality at large scale and long time series. The eco-environmental quality of Qilian Mountain National Park has developed in the right direction in recent years, although comprehensive management work needs further improvement. Related Articles | Metrics | Comments（0）

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Net primary productivity and carbon sequestration potential of salt marsh vegetation in Chongming Dongtan of the Yangtze Estuary based on CASA model. YUAN Yi-quan, XUE Li-ming, LI Xiu-zhen Chinese Journal of Ecology    2022, 41 (2): 334-342.   DOI: 10.13292/j.1000-4890.202201.025 Abstract （465）      PDF（pc） （2334KB）（210）       Knowledge map    Save Wetland ecosystems have strong carbon storage and sequestration abilities, playing an important role in global carbon cycle. To understand the carbon sequestration capacity of salt marsh wetlands, we estimated net primary productivity based on field investigation and remote sensing in a typical tidal creek system in the southern Chongming Dongtan Wetland. The carbon sequestration potential of salt marsh wetlands under environmental change was also estimated. The results showed that net primary productivity of halophytes exhibited significant temporal and spatial variations. The temporal variations were mainly reflected in the interannual differences and seasonal differences. The total net primary productivity of salt marsh in 2013 and 2017 was 245.70 and 257.75 t C·a-1, respectively, showing a slight increase. The net primary productivity in summer (97.70±69.31 g C m-2·month-1) was significantly higher than that in other seasons (P<0.05). At the spatial scale, net primary productivity decreased with elevation and Phragmites australis cohorts (1079.64±168.34 g C m-2·a-1) had significantly higher net primary productivity than other cover types (P<0.05). In 2017-2018, the carbon sequestration capacity of salt marshes in the study area was lower than the average level of carbon sequestration capacity of terrestrial vegetation in the same area. As the marsh matures gradually, carbon sequestration capacity can be further improved. Under the background of sea level rise, the positive succession of salt marsh vegetation compensates for the organic carbon loss caused by the erosion of salt marsh edge. The total carbon sequestration potential increased by 130.24-250.12 t·a-1. The continuous rise of global temperature and the changes of estuarine environment, such as sea level rise, shoreline erosion, vegetation succession and human disturbance, increase the uncertainty of salt marsh carbon sequestration ability. Prediction of its contribution to carboncycle will provide scientific support for carbon sequestration and increasing carbon sinks. Related Articles | Metrics | Comments（0）

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Wintering behavior and foraging strategies of six wild duck species in Poyang Lake. SHAO Ming-qin, ZENG Jian-hui, HE Wen-yun, ZHI Yi-jin, GONG Hao-lin, YANG Fu-cheng, DAI Nian-hua Chinese Journal of Ecology    2022, 41 (2): 294-299.   DOI: 10.13292/j.1000-4890.202202.005 Abstract （438）      PDF（pc） （454KB）（65）       Knowledge map    Save From October 2019 to January 2020 and October 2020 to January 2021, the behaviors of six wild duck species in Poyang Lake were studied using scan-sampling technique and focal sampling method. The results showed that foraging, resting, grooming, and locomotion were the most frequent behaviors. The proportion of time spent foraging compared with resting was significantly higher (P<0.01) in the Mallard (Anas platyrhynchos), Northern Pintail (Anas acuta), and Ruddy Shelduck (Tadorna ferruginea). The behavioral patterns of these three species were more foraging and less resting. In the Green-winged Teal (Anas crecca) and Eurasian Wigeon (Mareca penelope), the proportion of time spent on resting was significantly higher than that of foraging (P<0.01). The behavioral patterns of these two wild ducks were more resting and less foraging. The Eastern Spot-billed Duck (Anas zonorhyncha) showed no significant difference in the proportion of time spent on foraging to resting (P>0.05), indicating that foraging and resting behavioral patterns were of equal importance for this species. Body size of the six species was not significantly related to the proportion of time spent on foraging (P>0.05) or resting (P>0.05). Time budget was mainly determined by their behavioral patterns. The main foraging method of the Ruddy Shelduck was head and head-neck immersion in water. The other five species used head-neck immersion in water, which may be because their main food supply is under water. The differences in length of heads and necks among the six species resulted in spatial niche separation that decreased their interspecific competition. There was a significant negative correlation between diversity index of foraging patterns and the proportion of locomotion behaviors (r=-0.609, P<0.05) and a positive correlation between the diversity index of foraging patterns and the proportion time spent on foraging (r=0.936, P<0.01). The results showed that wild ducks with more diverse foraging patterns did not need to change their foraging sites frequently, thus reducing the time spent on moving to save energy. The weight of the Green-winged Teal, Eastern Spot-billed Duck, Mallard and Northern Pintail was significantly positively correlated with the duration of head-neck feeding (r=0.999, P<0.01), while was significantly negatively correlated with foraging frequency (r=-1.000, P<0.01). These results indicate that the six duck species have substantial differences in behavioral patterns and that foraging strategies are affected by body size of wild ducks, in that larger ducks adopt the strategy of increasing the feeding duration and smaller ducks adopt the strategy of increasing the frequency of foraging. Related Articles | Metrics | Comments（0）

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Progress in remediation technologies of heavy metals contaminated soil: Principles and technologies. WANG Hong-bo, GOU Wen-xian, WU Yu-qing, LI Wei Chinese Journal of Ecology    2021, 40 (8): 2277-2288.   DOI: 10.13292/j.1000-4890.202108.037 Abstract （391）      PDF（pc） （670KB）（367）       Knowledge map    Save Soil contamination by heavy metals is one of the global environmental problems, which is a major threat to environmental quality, human health, and national food security. To mitigate the adverse effects of heavy metals contamination, a variety of soil remediation technologies have been developed based on fundamental knowledge of physical, chemical, and biological sciences in the past decades, aiming to reduce the concentrations or bioavailability of heavy metals. Here, we reviewed ten remediation techniques, including encapsulation, landfilling, soil replacement, electrokinetic remediation, thermal treatment, vitrification, soil washing, stabilization/solidification, phytoremediation, and bioremediation. The principles, technical feasibility, and applicable conditions of all the technologies were evaluated, and the merits and disadvantages were discussed. In addition, we proposed that the basic earth science could contribute to the remediating of heavy metals contaminated soils as a natural attenuation process. Finally, we pinpointed how to choose a suitable remediation technology and how to fulfill key knowledge gaps and to overcome practical challenges. Related Articles | Metrics | Comments（0）

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Sexual and male horn dimorphism in adult Xylotrupes socrates tonkinensis (Scarabaeidae, Coleoptera, Insecta). BAI Tian-qi, XIE De-hong, CHEN Yu-fu, ZHANG Cui-xian, WANG Yong-fen, WEI Chao-jun, WANG Mei-cun, YI Huai-feng, ZHANG Yong, NI Zhang-guang Chinese Journal of Ecology    2021, 40 (8): 2496-2505.   DOI: 10.13292/j.1000-4890.202108.020 Abstract （339）      PDF（pc） （1669KB）（50）       Knowledge map    Save To elucidate the sexual and male horn dimorphism in adultXylotrupes socrates tonkinensis, multivariate statistical analysis was used to compare the differences of eight morphological traits between male and female, while allometry models of head horn length and thoracic horn length were used to determine the existence of horn dimorphism. The male-male competition behaviors of large and small males for females were observed in the laboratory. The results showed that the distributions of all traits, except tarsal length, overlapped considerably between males and females. The traits for males were generally larger than females (P<0.05). The coefficient variations of head horn length and thoracic horn length were 25.0% and 30.8% respectively, which were significantly larger than those of other measured traits. The values of head horn length and thoracic horn length followed normal distribution (P>0.05). The allometric relationships of head horn length and thoracic horn length to body size were fit with positive and simple linear models y=1.796x-2.8 (R2=0.765, P<0.05) and y=2.059x-2.628 (R2=0.951, P<0.05), respectively. Both small (head horn length <6.56 mm) and large males (head horn length>11.92 mm) that classified by probability grade could use horns to compete for females. Therefore, there is a sexual dimorphism. The head horn length and thoracic horn length of males had great variation, but without obvious horn dimorphism through allometric analysis. The dependence of reproductive strategies on body sizes of males needs to be further evaluated in the field. Related Articles | Metrics | Comments（0）

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Spatiotemporal variations of wind prevention and sand fixation function in the sand-prevention belt in Inner Mongolia in recent 15 years. LIU Li-min, WANG Ting-ting, LI Xiu-fen, XIE Zun-bo, WU Jin-zhou, SONG Li-ning Chinese Journal of Ecology    2021, 40 (11): 3436-3447.   DOI: 10.13292/j.1000-4890.202111.007 Abstract （330）      PDF（pc） （5824KB）（102）       Knowledge map    Save The wind prevention and sand fixation function are the main ecological service function of sand-prevention belt in northern China, which is important for the construction of ecological safety barrier in northern China. In this study, the sand-prevention belt in Inner Mongolia was selected as the study region, the revised wind erosion equation (RWEQ) was applied to quantify soil wind erosion mass and wind prevention and sand fixation mass in 2000 and 2015. We analyzed the spatial and temporal variations of wind prevention and sand fixation function, and the effects of land-use change on wind prevention and sand fixation function, aiming to provide reference for improving ecological service function of sand-prevention belt in northern China. The results showed that: (1) soil wind erosion mass ranged from 0.007 to 48.9 kg·m-2 in 2000, with a total soil wind erosion mass of 29418.3×108 kg, while it ranged from 0.002 to 48.2 kg·m-2 in 2015, with a total soil wind erosion mass of 28727.3×108 kg. From 2000 to 2015, the total amount of wind erosion in the whole region reduced by 691.1×108 kg. The intensity of soil wind erosion was mainly moderate, intensive, and severe, which together accounted for 71.6% of the total area in 2000, while it was mainly slight, moderate, and severe, accounting for 78.7% of the total area in 2015. The area of the regions with soil wind erosion of intensive, extreme, and severe intensity decreased by 101079 km2, while the area with soil wind erosion of mild and moderate intensity increased by 100572 km2. (2) The average amount of wind prevention and sand fixation per unit area ranged from 0 to 42.4 kg·m-2 in 2000, while it ranged between 0 and 45.4 kg·m-2 in 2015. The average amount of wind prevention and sand fixation per unit area was the highest in Chifeng City, followed by Tongliao and Ordos cities, while Wuhai and Shizuishan cities had the lowest values. The total amount of wind prevention and sand fixation in the study region was increased by 646.0×108 kg from 2000 to 2015. The level of wind prevention and sand fixation functions was mainly low, relatively low, and medium, together accounting for more than 75% of the total area. The area with wind prevention and sand fixation functions of relatively high and high levels increased by 1979 km2. (3) From 2000 to 2015, the total area of desertdecreased and was mainly converted into grassland and cultivated land. The converted grassland area was 6460.7 km2, while the converted cultivated land area was 439.2 km2. Our results indicated that the capability of wind prevention and sand fixation function in the sandprevention belt in Inner Mongolia significantly was improved over the past 15 years due to revegetation, but varied greatly among different parts of the study region. Therefore, we should take different strategies in different sand-fixing function zones, and pay more attention to the improvement of sand-fixing function in the western part. Related Articles | Metrics | Comments（0）

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Analysis of driving factors of vegetation NDVI change in Qilian Mountain National Park based on geographic detector. ZHANG Hua, LI Ming, SONG Jin-yue, HAN Wu-hong Chinese Journal of Ecology    2021, 40 (8): 2530-2540.   DOI: 10.13292/j.1000-4890.202108.022 Abstract （319）      PDF（pc） （2123KB）（152）       Knowledge map    Save Vegetation is a key link connecting the atmosphere, pedosphere, hydrosphere and biosphere. The relationship between the spatiotemporal variation of vegetation and its driving factors is of great significance in the research on regional environmental changes. Based on the datasets of vegetation NDVI, climate, vegetation type, geomorphology, soil type, and DEM, we analyzed the spatiotemporal variation of vegetation NDVI and driving factors in Qilian Mountain National Park from 2000 to 2019 using a geographic detector model. The results showed that: (1) Vegetation in Qilian Mountain National Park had gradual improvement from 2000 to 2019; (2) The area with low and medium-low grade NDVI accounted for more than 55% of total area, the area of middle and high grade accounted for about 35%, and the proportion of high-grade area was extremely low. Meanwhile, the vegetation NDVI showed a downward trend from east to west; (3) Precipitation, altitude, soil type, and temperature were the main factors affecting the variation of vegetation NDVI; (4) There were interactions among the evaluation indicators on vegetation NDVI, which were doublefactor enhancement and nonlinear enhancement effects; (5) The most suitable scope or categories for vegetation growth in Qilian Mountain National Park were as follow: mean annual rainfall of 320.7-385.8 mm, moisture index of 2.9-21.3, mean annual temperature of 0.2-5.2 ℃, vegetation types of coniferous and broad-leaved forest, soil types of black and gray forest soil, DEM of 2875-3365 m, ≥10 ℃ accumulated temperature of 346.2-720.5 ℃, geomorphic type of medium undulating mountain, slope of 17.1°-22.8°, slope direction of 0°-31.55°.   Related Articles | Metrics | Comments（0）

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Inhibitory effects of rhamnolipid crude extract on plant pathogenic fungi. CHEN Yao, SHI Rong-jiu, ZHENG Liang-can, HAN Si-qin, WANG Yan-hong, ZHANG Ying Chinese Journal of Ecology    2022, 41 (3): 520-527.   DOI: 10.13292/j.1000-4890.202202.035 Abstract （316）      PDF（pc） （1754KB）（84）       Knowledge map    Save Effects of biosurfactants on plant fungal diseases have been received much attention worldwide. Rhamnolipid is an anionic biosurfactant synthesized by Pseudomonas aeruginosa, with great potential as an inhibitor of plant pathogenic fungi. However, the comprehensive evaluation on its antifungal spectrum and antifungal activity is not fully explored. In this study, 29 common plant’s pathogenic fungi were collected. The sensitivity of pathogenic fungi at different taxonomic levels to the inhibition of rhamnolipid was evaluated based on Ainsworth fungal systemic taxonomy. The results showed that the inhibition effect of rhamnolipid on Oomycotawas the best. When the concentration of crude extraction of rhamnolipid was 0.3 g·L-1, the inhibition rate for Pythium attrantheridium, Pythium irregular, and Pythium acanthicum mycelium was 80%, followed by Deuteromycota. When the concentration was 0.5g·L-1, the inhibition rate for Verticillium dahliaeand Rhizoctonia solani reached higher than 80%. However, the effect of rhamnolipid was poor, even not effective to inhibit Ascomycetes andZygomycetes of pathogenic fungi. Furthermore, the observation of the morphological structure of fungal hyphae showed that rhamnolipid destroyed the cell wall of fungal mycelium and changed the permeability of cell membrane, and thus inhibited the growth of mycelium. As far as our knowledge, this study is the first one to show that rhamnolipid could inhibit the growth of Fusarium proliferatumand Fusarium redolens. The inhibition rate of rhamnolipid against hyphae was 63% and 74%, respectively, when the crude extraction of rhamnolipid was 1.0 g·L-1. This study comprehensively evaluated the antifungal spectrum and ability of rhamnolipid from taxonomic status of pathogenic fungi, which provided technical support for the development of biological control technology of plant’s pathogenic fungi. Related Articles | Metrics | Comments（0）

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Research advances on the endangered bird Mergus squamatus. LU Qing-bin, WANG Wei-bo, CHEN Yan-ji, XU Wei-nan, YANG Shu-zhen Chinese Journal of Ecology    2021, 40 (8): 2620-2634.   DOI: 10.13292/j.1000-4890.202108.017 Abstract （300）      PDF（pc） （821KB）（166）       Knowledge map    Save Chinese merganser (Mergus squamatus) is an endangered species with a long history. The progress in the research of Chinese merganser was systematically expounded in this review. The results showed that (1) For the population distribution: Russian Far East carried the main body of Chinese merganser breeding population, while China carried the main body of the wintering population. (2) For habitat selection: forest elements, water characteristics and concealment were the three factors determining habitat selection for Chinese merganser. (3) Behavior: behavior habits were mainly driven by temperature, sex ratio, and grouping characteristics. (4) Breeding ecology: nesting condition was one of the important factors limiting population breeding. (5) Endangered mechanism: the threatening factors included genetic diversity, self-habits and interspecific stress, and human activities were the main threat factor. (6) Conservation strategy: the habitat should be optimized according to the species’ habits and the conservation network should be constructed. Overall, current research mainly focused on ecology and related fields, forming the basic cognition of Chinese merganser. However, many conclusions were contradictory or generally speculative. Further research should be carried out from fidelity of wintering land, water area characteristics, and mating time. New technologies and ideas should be applied to deepen the understanding of Chinese merganser with multidisciplinary combination, so as to promote the effective protection of this rare species.   Related Articles | Metrics | Comments（0）

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Dynamics of gross primary productivity in Gansu Province based on VPM model. LI Liang, LIU Min-xia, SONG Jia-ying, ZHANG Guo-juan, WANG Si-yuan Chinese Journal of Ecology    2022, 41 (3): 554-561.   DOI: 10.13292/j.1000-4890.202202.028 Abstract （284）      PDF（pc） （3091KB）（90）       Knowledge map    Save Based on the vegetation photosynthesis model (VPM), we estimated gross primary productivity (GPP) in Gansu Province during 2005-2017, and explored the temporal and spatial variations, variation trend and influencing factors of GPP in different vegetation zones. The results showed that: (1) GPP increased significantly during 2005-2017, with a rate of 6.53 g C·m-2·a-1. There were significant differences of GPP among different vegetation zones, with the highest GPP of 1056.03 g C·m-2·a-1 in subtropical evergreen broad-leaved forest and the lowest GPP of 164.4 g C·m-2·a-1 in temperate desert. (2) In terms of spatial distribution, GPP showed adecreasing trend from southeast to northwest. Qilian Mountains, Qingyang, and southern Gansu were areas with high value. The areas with GPP greater than 500 g C·m-2·a-1 accounted for 40.15% of the total area, while the areas with sustained growth of GPP accounted for 83.65%. The areas with poor GPP stability accounted for 30.41%, which mainly distributed in Jiuquan, Wuwei, Lanzhou and Baiyin. The proportion of GPP high aggregation type increased from 29.53% to 30.14%. The high value of GPP increased and became more concentrated in Longnan and Qingyang. (3) The area of woodland increased significantly in Qilian Mountains, Baiyin and Longnan. The area of grassland increased significantly in Jiuquan and Zhangye, while bare land area decreased evidently. The increase of grassland and woodland areas and the reduction of bare land were the main reasons for the increases of GPP in Gansu. (4) The GPP in central Gansu increased with increasing air temperature and precipitation. Rainfall had a positive effect on the increases of GPP in northern Gansu, while temperature had a negative effect on GPP. The change of GPP in southern Gansu showed a contrary pattern. Related Articles | Metrics | Comments（0）

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Deciphering hosts of antibiotic resistance genes by metagenomic binning approaches in Union Glacier, Antarctica. LI Yi, XIA Cheng-qiang, FENG Yan, LI Hong, ZHANG Feng, GUAN Li, DONG Kai-shi, SHEN Shao-fei Chinese Journal of Ecology    2021, 40 (9): 2832-2841.   DOI: 10.13292/j.1000-4890.202109.038 Abstract （283）      PDF（pc） （2809KB）（128）       Knowledge map    Save Antimicrobial resistance (AMR), caused by antibiotic resistance genes (ARGs), is a growing threat to human health. Deciphering of ARG hosts is crucial for assessing the risk of AMR transmission from environment to human pathogens. Currently, ARG hosts in remote and pristine areas are poorly understood. Here, based on metagenomic data from Antarctic Union Glacier areas, the distribution pattern, resistance mechanism, and migration potential of ARG hosts were investigated by using metagenomic assembly and binning methods. A total of 80 MAGs (metagenomeassembled genomes) were constructed in the Antarctic Union Glacial soils, of which 18 MAGs could carry 86 ARGs (13 ARG types). The most commonly detected ARG types were related to multidrug, aminocoumarin, rifampicin, glycopeptide, and bata-lactams. Different ARGs present different host association resistance patterns. In the ARG hosts, 21 ACCs (ARG-carrying contigs) were found to carry MGEs (mobile genetic elements). Among those MDEs, translocase is the most common one, followed by transposase, integrase, conjugated transfer protein and recombinase. The MGEs and ARGs formed certain ARG-MGE co-existence patterns to promote the spread of AMR. In addition, due to carrying multiple ARGs, Escherichia, Burkholderiaceae, and Nocardioides members were important ARG repositories in Union Glacier soils. Together, these results provided basis for the risk assessment and control of environmental antibiotic resistance. Related Articles | Metrics | Comments（0）

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Application of soundscape monitoring technology in bird diversity monitoring at the typical wetland of Poyang Lake. YOU Hai-lin, WU Yong-ming, XU Li-gang, CHENG Jun-xiang, LIU Li-zhen, YAO Zhong, XIN Zai-jun Chinese Journal of Ecology    2021, 40 (9): 3025-3032.   Abstract （262）      PDF（pc） （2661KB）（185）       Knowledge map    Save Sound is a fundamental attribute of nature. Using the soundscape technology to monitor bird diversity and richness can effectively overcome the deficiency of traditional methods. The sound data of wetland birds at 00:00, 06:00, 12:00 and 18:00 of each day during April to June in 2020 were collected using Song Meter SM4, a professional collection instrument, in Fanglan Lake, a typical human-controlled lake in Poyang Lake. Using the professional sound processing packages (i.e. seewave, tuneR, and soundecology) in the statistical software R, all the collected sound data were analyzed and converted into bioacoustic index (BI). The main aims were to clarify the corresponding bird diversity and activity habits in the early morning, morning, noon and evening of each day during these three months, and to reveal the characteristics of bird diversity in a longtime sequence at the typical wetland of Poyang Lake. The MannKendall test method was used to analyze the trend and mutation of bird diversity characteristic sequence. The Morlet wavelet analysis method was applied to analyze its multitemporal scale characteristics. The results showed that: (1) The BI values at 00:00, 06:00, 12:00, and 18:00 within the three months were different, with ranges of 5.73-63.49, 5.76-67.00, 3.36-60.24, and 4.91-52.62, respectively. The BI values generally showed an increasing trend. (2) The Mann-Kendall mutation test indicated that all the BI sequences for three months had a sudden change around 06:00 on April 27 in 2020, which was mainly caused by human activities. (3) The evolution of daily average BI values showed three types of periodic change scales of 12-30, 10-18, and 4-9 days. The wavelet variance had three significant peaks, corresponding to the time scales of 24, 15, and 7 days. As an exploratory research, this study could provide a new technical approach for the research on bird population, behavior characteristic and its diversity, as well as the diversity monitoring research for other animals (amphibians, insects, etc.). Related Articles | Metrics | Comments（0）

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Effects of nitrogen deposition on soil microbes, enzyme activities, fine root production and turnover in forest ecosystems: A review. GUO Chao, WANG Lin-jiao Chinese Journal of Ecology    2021, 40 (11): 3730-3741.   DOI: 10.13292/j.1000-4890.202111.010 Abstract （260）      PDF（pc） （676KB）（117）       Knowledge map    Save Global nitrogen deposition is generally increasing year by year, with substantial effects on carbon and nitrogen cycling in forest ecosystems. Soil microbes, soil enzymes, and fine roots are important belowground components, playing crucial roles in the material circulation and energy flow of forest ecosystems. Their responses to nitrogen deposition have become a hot topic in the research field of global climate changes. Here, we summarized the effects of nitrogen deposition on soil microbes, enzyme activities, fine root production and turnover in forest ecosystems. Results showed that nitrogen deposition caused soil acidification, preserved soil nutrients, and changed the distribution pattern of belowground carbon and nitrogen. Effects of nitrogen deposition on the structures of soil microbial communities were mainly reflected in the increase or no change of soil bacteria/fungi ratio and changes in the relative abundance of soil microbes. Effects of nitrogen deposition on the functions of soil microbes were mainly reflected in promoting or inhibiting soil microbial respiration, changing nitrogenfixation groups, and reducing nitrogen use rate of soil substrate, and were significantly affected by soil pH, soil available nutrients, and the time of nitrogen application. Nitrogen deposition could promote or inhibit soil enzyme activities, which were significantly affected by soil depth, soil pH, and soil limiting elements (such as carbon, nitrogen and phosphorus). Along with increasing nitrogen deposition, fine root biomass decreased, fine root turnover speeded up or slowed down, fine root decomposition shifted from stimulating to inhibiting, which were significantly affected by soil nutrient availability, soil nitrogen storage, and fine root chemical properties. Focusing on the key scientific issues needed to be solved urgently in this research field, eventually we discussed important directions for future research. This review has great significance for further clarifying the mechanisms underlying the impacts of nitrogen deposition on soil microbes, enzyme activities, and fine root in forest ecosystems, and thus for the protection and rehabilitation of forest ecosystems under the background of increasing nitrogen deposition. Related Articles | Metrics | Comments（0）

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Age calibration and growth stage division for naturally regenerated seedlings and saplings of Pinus koraiensis Sieb. et Zucc. GE Xiao-wen, ZHU Jiao-jun, LU De-liang, ZHU Chun-yu, GAO Ping-zhen, YANG Xiao-yan Chinese Journal of Ecology    2022, 41 (3): 417-426.   DOI: 10.13292/j.1000-4890.202202.016 Abstract （259）      PDF（pc） （1858KB）（207）       Knowledge map    Save Accurately obtaining the age of regenerated individuals is the precondition for understanding regeneration status, quantifying regeneration age structure, and dividing regeneration stages, which is important for foresters to formulate reasonable forest management plan. However, two commonly used methods for age estimation of regenerated individuals have some deficiencies. Counting the number of rings (Nr) is destructive, while counting the number of whorls (Nw) lacks accuracy for many tree species including Korean pine (Pinus koraiensis). Further, the methods for growth stage division have not been uniformed. To accurately, efficiently, and non-destructively estimate the age of natural regeneration individuals of Korean pine, and divide growth stages of its regeneration layer reasonably, regeneration census including the root collar diameter and height of Korean pine (a total of 6831 individuals) was conducted in the primary mixed broadleaved-Korean pine forest in Lesser Khingan MountainsChangbai Mountains areas. Their ages were preliminarily estimated by traditional methods (counting the number of bud scars or whorls). Meanwhile, 153 regenerated individuals of Korean pine were destructively sampled by cutting base disk and counting Nr of the bottom section. Six calibration models between Nw and Nr were established. Method for growth stage division was proposed based on the biological characteristics of Korean pine and literature analysis (from 53 literatures). Results showed that directly using Nw as the age of regeneration individuals would underestimate age, while the calibrated Nw by the regression model (Nr=1.199Nw+2.962) was much closer to real age. According to the real age, height, and diameter at breast height (DBH) of regeneration individuals, the regeneration layer of Korean pine was divided into four stages, which were young seedlings (age ≤3 a), old seedlings (age >3 a and height <30 cm), small saplings (30 cm ≤ height <150 cm), and tall saplings (height≥150 cm and DBH <5 cm). Related Articles | Metrics | Comments（0）

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Fish community structure and diversity in Duhe River, a tributary of Hanjiang River. MENG Zi-hao, LI Xue-mei, WANG Xu-ge, HU Fei-fei, ZHU Ting-bing, WU Xing-bing, ZHU Yong-jiu, CHEN Kang, YANG De-guo Chinese Journal of Ecology    2022, 41 (2): 300-306.   DOI: 10.13292/j.1000-4890.202201.029 Abstract （251）      PDF（pc） （1154KB）（80）       Knowledge map    Save Based on the surveys of fish resources from June 2018 to May 2019, we analyzed fish community structure and species diversity in the Duhe River, and investigated the effects of environmental disturbance on fish community structure. Results showed that 38 species from 8 families and 4 orders were recorded, with cyprinids having most species (26), accounting for 68.4% of the total species captured during the investigation. Aristichthys nobilis, Opsariichthys bidens,and Hemiculter leucusculus were the dominant species in the river. Omnivorous, bottom, and settlement fish were mainly ecological types, accounting for 50.0%, 50.0%, and 89.5%, respectively. Hypophthalmichthys molitrix and A. nobilis accounted for 49.8% and 16.6% by relative weight and O. bidens,H. leucusculus, Zacco platypus accounted for 30.0%, 17.4%, and 12.7% by relative individual number, respectively. The fish community diversity indices were at the moderate or rich level. The Shannon index (H), Margalef index (R) and Pielou index (J) of the S3 region in the middle stream were higher than that of S1 and S2 regions in the upstream and S4 region in the downstream. The H and R of summer and autumn were higher than those of spring and winter, while the J of spring and winter was higher than that of summer and autumn. The community similarity (S′) indices among seasons were between 0.50 and 0.75, indicating moderately similar or higher. The community similarity (S′) indices of different two regions were moderately similar (S′>0.50), except that between S1 and S3 regions and between S3 and S4 regions, which were moderately dissimilar. The abundance-biomass curve (ABC) showed that biomass curve was above on abundance curve and W statistic was positive (0.0267>0), which indicated that fish community of Duhe River was relatively stable and was less affected by disturbance. However, compared with the historical data, fish species and ecological types have been changed. Accordingly, we proposed suggestions for the protection of fish resources in the Duhe River. Related Articles | Metrics | Comments（0）