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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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Responses of photosynthetic traits and adaptive mechanisms of Rhododendron pulchrum Sweet to different light environments. LENG Hanbing, SU Ming, ZHANG Chunying Chinese Journal of Ecology    2023, 42 (8): 1793-1801.   DOI: DOI:10.13292/j.1000-4890.202308.016 Abstract （17）      PDF（pc） （2473KB）（905）       Knowledge map    Save The aim of this study was to explore leaf photosynthetic and biochemical characteristics and adaptive mechanisms of Rhododendron pulchrum Sweet under different light environments, including full light (FL, 100% natural sunlight), slight shading (LS, 82.01% full light), moderate shading (MS, 50.13% full light), and severe shading (SS, 15.80% full light). The results showed that leaf area and the contents of photosynthetic pigments and total nitrogen increased with decreasing light intensity, while specific leaf mass, total carbon content and carbon/nitrogen ratio decreased, and chlorophyll a/b decreased firstly and then increased. Maximum quantum photochemical efficiency and non-photochemical quenching coefficient were significantly higher under MS and FL treatments than that under the other treatments, respectively. The actual quantum photochemical efficiency, photochemical quenching coefficient, and quantum yield of quenching under SS treatment were significantly lower than that under the other three treatments. Dark respiration rate and light compensation point decreased with decreasing light intensity, while the maximum values in apparent quantum efficiency, maximum net photosynthetic rate and light saturation point) were detected under MS treatment, suggesting the strongest photosynthetic capacity. R. pulchrum under FL treatment had lower net photosynthetic rate (Pn) accompanied with lower stomatal conductance and higher stomatal limitation value. Such decrease in Pn under FL treatment was mainly due to stomatal limitation. In comparison, Pn under SS treatment was inhibited mainly due to the reduction in photochemical efficiency and imbalance in fraction of incident light in photosystem Ⅱ. Our results suggested that R. pulchrum had good performance in tolerance range of light intensities, and that moderate shading (i.e., 50% full light) was optimal for its growth. Consequently, proper shading or community configuration under deciduous forest with sparse canopy should be employed regarding its cultivation or application in gardens. Related Articles | Metrics | Comments（0）

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Morphology and nutrient contents of fine roots from different orders in Fagaceae species in an evergreen broad-leaved forest. LI Shi-yi-ning, XIONG De-cheng, YAO Xiao-dong, WANG Xiao-hong, CHEN Ting-ting, JIANG Qi, JIA Lin-qiao, FAN Ai-lian, CHEN Guang-shui Chinese Journal of Ecology    2022, 41 (5): 833-840.   DOI: 10.13292/j.1000-4890.202205.010 Abstract （98）      PDF（pc） （1536KB）（605）       Knowledge map    Save We examined the interspcific and root order related variations in fine root morphology and stoichiometric traits of 8 Fagaceae species in an evergreen broadleaved forest in Wanmulin Nature Reserve of Fujian Province. The results showed that fine root diameter, tissue density (RTD) and C/N increased significantly, and specific root length (SRL) and N concentration decreased significantly, but C concentration showed no clear trend with increasing root orders. The main driver for interspecific variation in SRL depended on root orders: the interspecific variations of SRL for the first two orders were mainly caused by root diameter, while those for the higher root orders were caused by RTD. Moreover, the interspecific variations of root traits for the Fagaceae did not conform to a single axis, i.e., the “root economic spectrum”, but had two variation dimensions similar to those found on the global scale, that is, “do-it-yourself vs. mycorrhizal dependence” and “resource acquisition vs. conservation”. There were obvious differences in the ecological strategies of fine roots among different Fagaceae species. Related Articles | Metrics | Comments（0）

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Chinese Journal of Ecology    2023, 42 (8): 0-.   Abstract （181）      PDF（pc） （448KB）（554）       Knowledge map    Save Related Articles | Metrics | Comments（0）

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Effects of elevated CO2 and O3 concentrations on emission of isoprene and monoterpenes in Phoebe bournei. MA Fangyuan, ZHANG Li, WENG Zishan, LAI Jinmei, LIU Guizhen, GUO Hao, YI Zhigang Chinese Journal of Ecology    2023, 42 (8): 1802-1810.   DOI: 10.13292/j.1000-4890.202308.034 Abstract （17）      PDF（pc） （3567KB）（513）       Knowledge map    Save Elevated CO2 and O3 concentrations could affect ecosystem carbon (C) cycling. Isoprene (ISO) and monoterpenes (MTs) are the intermediate products in plant C metabolism, the synthesis and release of which are important pathways of ecosystem C cycling. We conducted a 4-month fumigation experiment with two-year-old Phoebe bournei seedlings. Four treatments, namely the control (CK), elevated CO2 concentration (EC), elevated O3 concentration (EO) and simultaneously elevated CO2 and O3 (EC+EO), were set up to examine the effects of elevated CO2 and O3 concentrations on ISO and MTs release and photosynthetic parameters in P. bournei. The results showed that after one month fumigation, a significant increase in MTs fluxes (P<0.05) and a 5.6% decrease in ISO flux were observed with the EC treatment compared with CK. After 4 months’ fumigation, the ISO and MTs fluxes decreased under EC, EO, and EC+EO treatments. The reduction was the strongest under EC+EO treatment, with the ISO and MTs fluxes being reduced by 76.4% and 89.6%, respectively. The decrease of fluxes might be attributed to the changes of net photosynthetic rate by changing the content of photosynthetic pigments and adjusting stomatal conductance under different treatments, which directly affects C source of ISO and MTs metabolism. The main components of MTs were α-pinene and limonene. Under elevated CO2 and O3 concentrations, net photosynthetic rate gradually decreased with fumigation duration. The effects of independently and simultaneously elevated CO2 and O3 concentrations on ISO and MTs fluxes differed. When we investigated the effects of elevated CO2 and O3 concentrations on ecosystem C cycling, compound factor interaction experiments should be taken into consideration, to provide more reliable data support for understanding the responses of ecosystem C cycling to global climate change. Related Articles | Metrics | Comments（0）

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Quantitative classification and phylogenetic structure of vegetation in valley of the middle and upper reaches of Lancang River. ZUO Yan-jie, SHU Guo-biao, WANG Chong-yun, PENG Ming-chun, XIE Ying-xu, ZHANG Qiu-yuan, LI Fu-li Chinese Journal of Ecology    2021, 40 (9): 2665-2677.   DOI: 10.13292/j.1000-4890.202109.020 Abstract （143）      PDF（pc） （2276KB）（509）       Knowledge map    Save Lancang River valley, with unique history of geological evolution and the longitudinal change of ecological environment, provides an ideal place for understanding the differentiation and assembling process of plant communities. In this study, we comprehensively used the methods of TWINSPAN quantitative classification, community ordination, and phylogenetic structure analysis to elucidate the community characteristics and maintenance mechanisms of the valley vegetation in the middle and upper reaches of Lancang River. The results showed that: (1) According to TWINSPAN classification, plant communities in the middle and upper Lancang River valley were divided into 28 types. The result of the classification was similar to the DCA twodimensional ranking map. CCA and DCCA ordination showed that elevation was the major environmental factor affecting vegetation distribution. (2) Among the 28 community types, the average net relatedness index (NRI) value of 19 communities was greater than 0. The environmental filtering effect of river valley habitat was obvious. The phylogenetic structure of the plant communities generally showed an aggregation pattern. (3) Dryhot scrubs and drywarm scrubs had a narrow range in the river valley, including Ass. Buddleja crispa,Ass. Sageretia horrida+Sophora davidii,Ass. Elsholtzia capituligera +Caryopteris forrestii,Ass.Osteomeles schwerinae–Gramineae sp., Ass. Elsholtzia fruticose +Artemisia gyitangensis,Ass. Vitex negundo f. laxipaniculata+Pistacia weinmannifolia. Community phylogenetic structure generally had a significant aggregation pattern (P<0.05). The phylogenetic structure of widespread plant communities, including Ass. Cyclobalanopsis glaucoides, Ass. Pinus yunnanensis, Ass.Picea likiangensisvar. rubescens, and Ass.Betula platyphylla, showed a significant divergent pattern (P<0.05). (4) Ass. Castanopsis delavayi+Quercus variabilis had the highest average of phylogenetic diversity (PD), but species abundance was not the highest. (5) Ten climatic and topographic factors could explain 40.8%, 38.59%, and 9.97% of the variation of species richness, PD and NRI, respectively. Environmental differentiation in the Lancang River valley was illustrated by numerical classification and ordination analysis of plant communities. Combined with the analysis of the phylogenetic structure, the environmental factors that lead to ecological differentiation of river valley vegetation were revealed, reflecting the diversity and complexity of the river valley habitats. Related Articles | Metrics | Comments（0）

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Effects of different ratios of  nitrogen and phosphorus addition on the relationship between relative growth rate and fine root traits of Machilus pauhoi seedlings. CHENG Jieru, ZHONG Quanlin, ZOU Yuxing, CHANG Yunni, LIAO Penghui Chinese Journal of Ecology    2023, 42 (8): 1811-1819.   DOI: 10.13292/j.1000-4890.202308.011 Abstract （22）      PDF（pc） （2026KB）（465）       Knowledge map    Save Nitrogen (N) and phosphorus (P) are important nutrients affecting plant growth. Fine root is an important organ to absorb nutrients and water. Here, we analyzed the effects of different N and P application ratios (15∶1, 12∶1, 10∶1, 8∶1) on the growth and fine root traits of 1-year-old Machilus pauhoi seedlings in a pot experiment. The results showed that: (1) All the N and P addition treatments significantly increased leaf biomass, total biomass, and leaf mass fraction, but decreased root-shoot ratio, especially at the treatments with N/P ratios of 10∶1 and 8∶1. (2) Combined applications of N and P significantly increased relative growth rates of both total biomass and biomass of each organ, with a strongest effect under N/P ratio of 10∶1. (3) Combined applications of N and P significantly increased N and P concentrations in fine roots (P<0.05), with no difference among treatments. Fine root N concentration was the highest in the treatments with N/P ratios of 15∶1 and 10∶1. Fine root P concentration was the highest in the treatment with N/P ratio of 10∶1. Combined applications of N and P reduced the average diameter of each fine root order and specific surface area (SRA) of the 1st-2nd order roots, but increased specific root length (SRL) of the 2nd-4th order roots and SRA of the 3rd-4th order roots. The changes of root tissue density (RTD) of each order was opposite to that of SRA. (4) The relative growth rates of total biomass and biomass of each organ were significantly positively correlated with RTD but negatively correlated with SRL and SRA after combined N and P application. The results indicated that application of different N/P ratios affected biomass allocation pattern, relative growth rate, and the relationship between relative growth rate and some fine root traits of M. pauhoi seedlings. The most suitable ratio of N/P for the growth of M. pauhoi seedlings was 10∶1. Our results provide an important reference for the development of precise nutrient management and efficient cultivation of M. pauhoi seedlings. Related Articles | Metrics | Comments（0）

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Responses of leaf functional traits and carbon and nitrogen allocation in hybrid poplar (Populus ×euramericana ‘Zhongjin2’) seedlings under twoyear nitrogen addition. GAO Tian-hui, WANG Wei-feng, SHANG Jia-zhou, LI Tao, WANG Sheng-ji Chinese Journal of Ecology    2022, 41 (5): 841-848.   DOI: 10.13292/j.1000-4890.202204.011 Abstract （155）      PDF（pc） （1754KB）（454）       Knowledge map    Save Atmospheric nitrogen deposition affects forest ecosystems. The ecophysiological process and mechanism of trees in response to nitrogen deposition need further clarification. To explore the changes of photosynthetic traits, biomass accumulation, and carbon and nitrogen allocation in poplar under nitrogen addition, hybrid poplar (Populus ×euramericana ‘Zhongjin2’) seedlings were grown in pots under a rainout shelter in a semiarid area of China. Seedlings were treated with different nitrogen addition levels (0, 3, 6 and 9 g NH4NO3·a-1·plant-1) for two years. Leaf photosynthetic rate, leaf  functional traits, organ biomass, and carbon and nitrogen allocation were investigated. In the first year, with the increases of nitrogen addition levels, leaf area significantly increased but leaf became thinner, with decreased mesophyll tissue thickness. Leaf area based net photosynthetic rate and stomatal conductance increased firstly and then decreased with increasing nitrogen addition level, while transpiration rate, instantaneous water use efficiency and photosynthetic nitrogen use efficiency did not change. Whole plant biomass and carbon and nitrogen accumulation significantly increased. The carbon investment in stem increased significantly while that in root decreased significantly. In the second year, photosynthetic carbon fixation rate of functional leaves reached saturation more quickly with increasing nitrogen addition level, with toxicity of high-dose addition. The biomass accumulation of individual plant increased significantly and carbon investment to stem was increased in low nitrogen addition, while root growth was inhibited in high nitrogen addition. The enhanced leaf water consumption in response to nitrogen addition may be one of the driving factors of carbon investment to stem, while the decreasing root shoot ratio may reduce the resistance of poplar seedlings to frequent drought in semiarid area. 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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Changes of soil enzyme activity and their stoichiometric characteristics during secondary succession of Quercus liaotungensis forests. YAN Ben-shuai, SUN Li-peng, LI Jing-jing, GAO Li-qiang, QIAO Zhan-guo, GAO Xiao-feng, WU Chun-xiao, WANG Guo-liang Chinese Journal of Ecology    2022, 41 (4): 641-647.   DOI: 10.13292/j.1000-4890.202203.035 Abstract （114）      PDF（pc） （617KB）（356）       Knowledge map    Save Soil extracellular enzymes play an important role in soil nutrient cycling. However, the mechanism underlying the changes of soil enzymes during vegetation succession is not clear. In this study, on the basis of substituting space for time, cropland and Quercus liaotungensis forests after 30, 60 and 120 years restoration were selected as research objects to examine the changes and driving factors (vegetation and soil physicochemical characteristics, and microbial biomass) of soil enzyme activities and their stoichiometry in the process of secondary succession in Fuxian County, Shaanxi Province. Across the chronosequence, the activities of β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), and leucine aminopeptidase (LAP) showed an increasing trend, that of alkaline phosphatase (AP) first increased, then decreased and then increased, reaching a maximum value after 120 years of vegetation restoration. The activities of BG, LAP+NAG and AP ranged 25.96-40.96, 57.10-128.05, 65.41-126.60 nmol·g-1·h-1, respectively. BG/(LAP+NAG) and BG/AP in the cropland were higher than those in the 30-year-old forest, while (LAP+NAG)/AP showed an opposite trend. In the cropland, soil microbial metabolism was mainly limited by C and P. With vegetation succession, BG/(LAP+NAG) increased gradually, and (LAP+NAG)/AP and BG/AP increased first and then decreased, indicating that the limitation of C and P on microbial metabolism was alleviated and shifted to N limitation. RDA results showed that soil enzyme activities and their stoichiometry were mainly affected by soil microbial biomass, ammonium nitrogen, and root biomass during the secondary succession. In conclusion, vegetation succession alters microbial metabolism by affecting soil nutrient content, with consequences on soil nutrient cycling. Related Articles | Metrics | Comments（0）

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Variations of leaf and fine-root functional traits of five garden tree species across an urban-rural gradient. CHEN Leiru, MA Ruihao, WANG Fei, XIA Kai, DENG Pengfei, XU Xiaoniu Chinese Journal of Ecology    2023, 42 (6): 1281-1289.   DOI: 10.13292/j.1000-4890.202305.027 Abstract （27）      PDF（pc） （2350KB）（355）       Knowledge map    Save Functional traits are important characteristics that link plants, environment and ecosystems, with a far-reaching significance for indicating environmental changes. In this study, we measured 14 morphological, physiological, and nutrient traits of leaf and fine-root in five garden evergreen tree species, Photinia ×fraseri, Euonymus japonicas ‘Aurea marginatus’, Cinnamomum camphora, Ligustrum lucidum, and Osmanthus fragrans. The differential variations of traits across an urban-rural environmental gradient and the correlation between leaf traits and root traits were analyzed to reveal the survival and adaptation strategies of these species. The results showed that morphological traits of different tree species differed greatly. There were no significant differences in the leaf morphological traits along the urban-rural gradient. The physiological traits showed an increasing trend along the urbanrural gradient, and the similar trend was observed for carbon contents in fine roots and leaves. According to the results of principal component analysis and the theory of plant economic spectrum, the fine roots of the garden tree species tended to adopt a “conservative” strategy, and the survival strategy of tree species as whole appeared “slow investment return” type in the rural sites. This survival strategy was not found in the urban sites. Our findings indicate that urbanization may strengthen the resource acquisition ability of plants for growth and production. Related Articles | Metrics | Comments（0）

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Research progress on net carbon sequestration capacity of plants under the background of carbon neutra-lization. YANG Qianmin, YUAN Danping, DENG Cunbao, WANG Yansheng, QIAO Ling Chinese Journal of Ecology    2023, 42 (6): 1484-1496.   DOI: 10.13292/j.1000-4890.202306.015 Abstract （138）      PDF（pc） （1296KB）（342）       Knowledge map    Save Plants play a key role in regulating the balance of atmospheric CO2 concentrations, improving carbon sequestration capacity and ecosystem carbon stocks, and contributing to the mitigation of global warming. It is therefore of great significance to further understand the factors affecting the net carbon sequestration capacity of plants in order to achieve the targets of carbon peak and carbon neutralization in China. We summarized the recent progresses in carbon fixation pathways in photosynthesis, carbon release processes through litter decomposition, and factors (CO2 concentration, temperature, water content, litter addition and removal) affecting carbon sequestration and carbon release through CO2 and CH4 emissions. The results showed that there was a threshold for the promotion of water, temperature, and CO2 concentration on plant carbon sequestration and the promotion of water and temperature on the CO2 emission from litter decomposition. When the threshold exceeds a certain range, an inhibitory effect exists on the aforementioned process. Litter removal is beneficial to reducing CO2 emission, but the response of CH4 emission through litter decomposition to the above environmental factors has been inconclusive. We propose to strengthen studies on the carbon sequestration ability of plants in different stages of life cycles by the combined action of multiple environmental factors; and on carbon emission mechanisms of tree residues, belowground litter, root exudates, and their responses to environmental factors, which will provide a reference for improving plant carbon sequestration and carbon neutrality. Related Articles | Metrics | Comments（0）

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Effects of nitrogen addition on biomass and root morphology of Phyllostachys edulis seedlings under drought stress. GAO Ge, LI Zheng-cai, GE Xiao-gai, HUANG Run-xia, LI Ai-bo Chinese Journal of Ecology    2022, 41 (5): 858-864.   DOI: 10.13292/j.1000-4890.202203.017 Abstract （135）      PDF（pc） （1192KB）（327）       Knowledge map    Save We investigated the responses of aboveground biomass and root morphological characteristics of Phyllostachys edulis seedlings to nitrogen addition under different levels of drought stress. The experiment followed a two factor completely random block design, with three levels of soil water condition (CK, MD, and HD with 80%-85%, 50%-55%, and 30%-35% of field water holding capacity, respectively) and two levels of nitrogen addition (N0, 0 mg N·kg-1; N1, 100 mg N·kg-1). The root morphological characteristics and biomass of seedlings were measured. The results showed that nitrogen addition increased the biomass of leaf and root inPh. edulis seedlings under the same water level. Compared with N0MD and N0HD, the aboveground biomass of N1MD and N1HD increased by 15.6% and 11.9%, while the total biomass increased by 36.7% and 25.0%, respectively (P<0.05). Nitrogen addition reduced the specific root length and stem/leaf ratio of Ph. edulis seedlings under the same water level, but significantly promoted root/shoot ratio under moderate and high drought stresses (P<0.05). Under water stress, the proportion of root biomass increased significantly, while the proportion of stem and leaf biomass showed a decreasing trend with nitrogen addition. Nitrogen addition improved root morphological characteristics (root length, root surface area, root volume) of Ph. edulis. Nitrogen addition showed stronger enhancement on dry matter accumulation of Ph. edulis seedlings under moderate drought than under high drought stress, while better alleviated the stress of high drought on root morphology. In conclusion, nitrogen application prompted Ph. edulis to adjust its biomass allocation under drought stress to optimize the access to limited resources. It also facilitates to shape root morphological characteristics through alleviating the inhibitory effect of drought on the growth of Ph. edulis seedlings. Related Articles | Metrics | Comments（0）

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Responses of plant community structure and stability to artificial disturbance in urban remnant mountains. SUN Yuzhen, WANG Zhitai, BAO Yu, LIU Shuping Chinese Journal of Ecology    2023, 42 (8): 1829-1840.   DOI: 10.13292/j.1000-4890.202308.010 Abstract （14）      PDF（pc） （3090KB）（326）       Knowledge map    Save To explore the responses of plant community of urban remnant mountains to artificial disturbance, plant community structure and stability of urban remnant mountains under different artificial disturbance ways and intensities were analyzed using the theories and methods of community ecology and quantitative ecology. The results showed that: (1) Vertical structure integrity of plant community under different intensities of human disturbance declined with increasing disturbance density. Reclamation, excavation, and construction had significant negative effects on trees and shrubs, while park utilization was beneficial to the integrity of community vertical structure. (2) The diameter class structure of trees exhibited an inverted “J” type distribution under different disturbance intensities. Small diameter trees (DBH<10 cm) accounted for 53%, 58% and 48% of the total individual numbers in the plots under light, moderate and heavy disturbances, respectively. The regeneration potential of tree layer was high. The diameter class structure of tree changed abnormally under reclamation and excavation disturbance ways. (3) Based on the coefficient of variation of community density and the Godron stability index, community stability decreased with human disturbance intensities. Plant communities under the disturbances of trample and park utilization were relatively stable, while those with the reclamation and engineering excavation were most unstable. 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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Effects of strip cutting width on the concentrations and stoichiometry of soil C, N, and P in Phyllostachys edulis forests. SHEN Jingxin, FAN Shaohui, LIU Guanglu, WEI Songpo Chinese Journal of Ecology    2023, 42 (8): 1851-1857.   DOI: 10.13292/j.1000-4890.202308.013 Abstract （18）      PDF（pc） （1192KB）（298）       Knowledge map    Save Strip cutting of moso bamboo forests is a new strategy proposed in recent years to adapt to mechanized operation. Understanding the effects of strip cutting width on soil nutrient contents and stoichiometric ratios is of great significance for selecting reasonable cutting width and realizing sustainable management of moso bamboo forests. In this study, we compared the effects of different cutting widths (3, 6, 9, and 12 m) on the contents and ratios of soil C, N, P, with moso bamboo forest under traditional selective cutting as the control (CK). The results showed that with the increasing cutting width, the contents of soil C, N and P increased at first and then decreased. The contents of soil C, N, and P were the highest at 6 m and the lowest at 12 m. Soil C/P and N/P increased first and then decreased with increasing cutting width, whereas C/N was relatively stable. The cutting width of 6 m had significantly greater soil C/P than the cutting width of 12 m, while the cutting width of 3 m and 6 m had significantly greater soil N/P than the cutting width of 12 m. In conclusion, the cutting width of 6 m was most beneficial to the accumulation of soil C and N, with higher C/N, C/P, N/P, and more balanced nutrient ratios. Moreover, moso bamboo forest was influenced by the dual constraints of N and P contents, and soil P was more deficient. It is necessary to ensure soil nutrient balance through P fertilizer application and promote the rapid recovery of moso bamboo forest in strip cutting areas in the short term. Related Articles | Metrics | Comments（0）

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Effects of stumping height on carbon, nitrogen, and phosphorus stoichiometry in different organs of Pinus yunnanensis seedlings. CAI Nian-hui, TANG Jun-rong, CHE Feng-xian, CHEN Shi, WANG Jun-min, XU Yu-lan, LI Gen-qian Chinese Journal of Ecology    2022, 41 (5): 849-857.   DOI: 10.13292/j.1000-4890.202203.012 Abstract （140）      PDF（pc） （2182KB）（296）       Knowledge map    Save To understand the effects of stumping on the contents and stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in different organs of Pinus yunnanensis seedlings, and the correlations and allometric relationships among C, N and P, the contents of C, N, P and the ratios of C∶N, C∶P and N∶P in seven organs (taproot, lateral root, stem, lateral branch, mother plant needle, sprout branch, sprout needle) of P. yunnanensis seedlings with different stumping heights (CK, 5, 10 and 15 cm) were analyzed. The results showed that N, P, C∶N, C∶P, N∶P had significant differences among stumping heights, organs, stumping heights×organs, except that C content showed no response to stumping height. With the increases of stumping height, N, P, C∶N, C∶P, N∶P showed a trend of first increase and then decrease, while C∶N and C∶P showed an opposite trend. The variation coefficients of contents and ratios of elements in each organ fluctuated slightly under different stumping heights, indicating that stumping had little effect on C, N, P contents and their stoichiometric stability. The correlations between C and N and between C and P changed among different stumping heights, while the correlations between C and N and between C and P were weakened with increasing stumping height. Stumping did not affect the allometric growth relationship between them, with the accumulation rate of C being lower than that of N and P, and the growth of seedlings being mainly regulated by N. In summary, stumping changed nutrient content, and then changed the balance of C, N and P in plants. The performance of P. yunnanensis seedlings was mainly regulated by N. With increasing stumping height, the utilization of N and P in seedlings decreased first and then increased, at the same time the degree of N limitation decreased first and then increased. Related Articles | Metrics | Comments（0）

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Effects of elevated CO2 concentration on photosynthetic characteristics of Schima superba seedlings. PAN Hong, CAO Ji-xin, CHEN Zhan, SHANG He Chinese Journal of Ecology    2022, 41 (5): 865-872.   DOI: 10.13292/j.1000-4890.202203.036 Abstract （96）      PDF（pc） （2461KB）（284）       Knowledge map    Save Few studies have explored plant responses to all of CO2 scenarios including 430-480, 580-720, 720-1000 and more than 1000 μmol·mol-1 which will be by 2100 predicted by the IPCC (Intergovernmental Panel on Climate Change). In this study, one-year-old seedlings of Schima superba were exposed to ambient air and three elevated CO2 concentrations of 550, 750, 1000 μmol·mol-1 to investigate the changes of gas exchange parameters, photosynthetic pigment contents, and biomass by using Open Top Chambers during growing season. The results showed that net photosynthetic rate was increased by 32.7%, 66.7%, and 82.7%, and intercellular CO2 concentration was increased by 60.3%, 126.2%, 223.9% at 550, 750, and 1000 μmol·mol-1, respectively. The improvement in net photosynthetic rate under elevated CO2 concentrations decreased as affected by non-stomatal factors (such as decreased leaf N content) after longer fumigation time. Stomatal conductance and transpiration rate increased under all elevated CO2 concentrations from May to July, while there was no significant difference between 1000 μmol·mol-1 and ambient treatments from August to October. The reduction of the contents of chlorophyll a, chlorophyll b, carotenoids, and N in leaves under 750 and 1000 μmol·mol-1 was higher than that under 550 μmol·mol-1. Biomass under the treatments of 550 and 750 μmol·mol-1 increased by 79.2% and 48.9%, respectively, but decreased under 1000 μmol·mol-1. Therefore, it would be beneficial for S. superbato fix the increasing CO2 in atmosphere and preserve water in body under elevated CO2 concentrations. These benefits would increase the adaptability of S. superba seedlings to arid environments and enhance biomass accumulation under CO2 concentrations of 550 and 750 μmol·mol-1. Related Articles | Metrics | Comments（0）

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Evolution of the supply and demand pattern of ecosystem services in Hunan Province. WANG Ying-li, XU Xin-liang, ZHUANG Da-chun, DONG Xian-bin, YANG Xue-qing, ZOU Yu-yang, FAN Jian, LIU Ya-fei Chinese Journal of Ecology    2021, 40 (10): 3268-3277.   DOI: 10.13292/j.1000-4890.202110.029 Abstract （118）      PDF（pc） （18681KB）（280）       Knowledge map    Save The rapid urbanization and human activities have huge impacts on land use change and ecological environment in Hunan Province. Based on land use data in four phases of 2000, 2005, 2010, and 2015, we used the equivalent factor method and multi-index model to calculate the ecosystem service supply and demand caused by land use change and then examined the characteristics of temporal and spatial evolution. The results showed that forestland and farmland were the dominant land use types in Hunan Province. During the study period, land use pattern changed significantly. Farmland area decreased the most (by 1165 km2), the construction land area increased the most (by 1611 km2),  thus resulting in a land use characteristics of changing from farmland to construction land and forestland. The supply of ecosystem services in Hunan increased by 9.20% from 1.83×1010 yuan in 2000 to 1.99×1010 yuan in 2015. The demand index of ecosystem services rose by 45.87% from 365480 in 2000 to 533130 in 2015. The spatial distribution of ecosystem service supply and demand in Hunan was unbalanced. The contradiction between supply and demand of ecosystem services was more prominent in Changsha-Zhuzhou-Xiangtan urban agglomeration, the junction of Changde City and Yiyang City, and Hengyang City in southern Hunan. Our results can provide theoretical reference for the coordinated and sustainable development of regional economy and ecological environment in Hunan Province. Related Articles | Metrics | Comments（0）

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Root exudation rate and rhizosphere effect of different mycorrhizal associations of tree species in typical black soil area. JIANG Zhi-yan, ZOU Qing-qin, YANG Liu, LI Wen-zhuo, ZHANG He-dong, CHEN Xiang-wei, WANG Xiu-wei Chinese Journal of Ecology    2021, 40 (9): 2709-2718.   DOI: 10.13292/j.1000-4890.202109.001 Abstract （186）      PDF（pc） （1655KB）（278）       Knowledge map    Save We examined root exudation rate and rhizosphere effect of four arbuscular mycorrhizal (AM;Amygdalus triloba, Acer negundo, Viburnum opulus subsp. calvescens, and Armeniaca sibirica) and three ectomycorrhizal tree species (ECM; Picea koraiensis, Betula platyphylla, and Pinus sylvestris var.mongolica), to determine the differences of different mycorrhizal associations of tree species and to evaluate their improvement on soil quality in the black soil at Keshan Farm in Heilongjiang, China. The results showed that root exudation rate of the seven tree species was significantly different (P<0.05), with that of the ECM tree species being significantly higher than that of AM tree species (P<0.05). The pH of Viburnum sargenti, Armeniaca sibirica andAcer negundo rhizosphere soil was 0.3%-5.9% higher than the bulk soil. In contrary, it was1.9%-5.1% lower in Amygdalus triloba, Picea koraiensis, Betula platyphylla, and Pinus sylvestris var.mongolica rhizosphere soil. Rhizosphere effects on soil total organic carbon (TOC), total nitrogen (TN), alkalihydrolyzed nitrogen (AHN), total phosphorus (TP), and available phosphorus (AP) in the rhizosphere soil of the seven tree species were 22.1%-250.4%, 9.9%-146.9%, 5.5%-23.8%, 3.8%-48.8% and 23.6%-189.1% higher compared to bulk soil, respectively. The rhizosphere effects of the ECM tree species on TOC, TN, and AHN were greater than that of the AM tree species, while that on soil TP and AP was lower than the AM tree species. Compared to the bulk soil, the abundance of bacteria and actinomycetes in the rhizosphere soil of the seven tree species was increased by 42.9%-309.6% and 13.3%-134.7%, respectively. The abundance of fungi in the rhizosphere soil of Armeniaca sibirica and Amygdalus triloba was decreased by 21.6% and 8.6%, respectively, but increased by 43.5%-215.4% in the rhizosphere soil of other tree species. The rhizosphere effect on the abundance of bacteria and fungi in the ECM tree species was greater than that of the AM tree species (P<0.05), while the rhizosphere effect on actinomycetes was not different between the AM and ECM species (P>0.05). The correlation among root exudation rates, microbial quantity, and soil chemical properties in AM species was significantly greater than that in the ECM species. The effect of ECM tree species on soil improvement was stronger than that of AM tree species. Related Articles | Metrics | Comments（0）