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ISSN 0256-307X(Print)
ISSN 1741-3540 (Online)
CN 11-1959/O4
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  Chinese Journal of Applied Ecology--2018, 29 (12)   Published: 20 December 2018
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Reviews

Advances in joint species distribution models to reveal community structure and its environmental response

ZHU Yuan-jun, SHAN Dan, ZHANG Xiao, LIU Yan-shu, SHI Zhong-jie, YANG Xiao-hui
Chinese Journal of Applied Ecology. 2018, 29 (12): 4217 doi: 10.13287/j.1001-9332.201812.009
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Species distribution models are commonly used in basic and applied ecological research to examine the factors driving the distribution and abundance of organisms. They are employed to quantify species’ relationships with abiotic conditions, to predict species’ response to land-use and climatic change, and to identify potential conservation areas. Biotic interactions have been rarely included in traditional species distribution models, wherein joint species distribution models (JSDMs) emerge as a feasible approach to simultaneously incorporate environmental factors and interspecific interactions, making it a powerful tool for analyzing the structure and assembly of biotic communities. Generally, the JSDMs are based on species distribution models (SDMs), with the abundance or occurrence of multiple species as response variables and environmental factors, species associations and species traits being incorporated in the modeling framework. These models commonly use generalized linear regression methods (GLM) to relate multivariate response to environmental variables, and capture species associations in the form of random effects. The limitation has been overcome by the introduction of latent variable models (LVMs). Typically, the model parameters are estimated using maximum likelihood estimation or Bayesian methods implemented by Laplace Approximation and Markov Chain Monte Carlo (MCMC) simulations, respectively. In this review, the generation and theoretical basis of JSDMs were summarized. The characteristics of different types of JSDMs and their applications in modern ecology were emphatically introduced. The problems and prospects of JSDMs were discussed. With the in-depth study of the relationship between environmental factors and multi-species interactions, JSDMs would be the focus of future studies of species distribution model.

Urban energy water food land climate change nexus in the flow and policy perspective: A review

XUE Jing-yan, LIU Geng-yuan
Chinese Journal of Applied Ecology. 2018, 29 (12): 4226 doi: 10.13287/j.1001-9332.201812.038
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Intricate associations exist between the internal elements of urban ecosystems, with the adjustment in one element can exert impacts of varying degrees on others. The rapid urbanization has brought numerous challenges on the urban sustainable development. To basically solve these problems, the “nexus” approach needs to be adopted. We clarified three application scenarios of “nexus” and their corresponding definitions. Meanwhile, the development of urban nexus theory was also provided. The analysis between any two characters among energy, water, food, land and climate change (EWFLC) systems was presented from the perspective of the physical nexus and policy effect nexus, respectively. From the perspective of the physical nexus, most the present stu-dies are concentrated on the urban scale, and aim at the direct nexus, lacking of indirect nexus reaches relatively. Most of the relationships between each two characters will have positive impacts on the society or economy. From the perspective of the policy effect nexus, current policies focused on the five systems are mostly oriented to directly solve problems of targeted system. The intermediate objectives of policy implementation are mostly quantifiable. There are generally multiple indicators of the policy effect evaluations. Furthermore, an analysis framework of urban EWFLC systems simultaneously combining physical and policy nexus was proposed in this study, which aimed to help make policy selections and realize urban sustainable development.

Influence of elevated CO2 on nitrification and denitrification in water bodies: A review

SHI Man, ZHANG Wei-guo, LI Jiang-ye, YAN Shao-hua, GAO Yan
Chinese Journal of Applied Ecology. 2018, 29 (12): 4239 doi: 10.13287/j.1001-9332.201812.037
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Elevated atmospheric CO2 has imperceptible impacts on carbon cycle in aquatic ecosystems. However, it remains a question how this process will impact nitrogen cycle that is naturally coupled with carbon cycle. The nitrification and denitrification are two critical processes in the nitrogen cycle. It is reasonable to expect that elevated atmospheric CO2 will influence both processes. We reviewed the previous literatures concerning the effects of elevated atmospheric CO2 on the physico-chemical properties, nitrification, denitrification and nitrogen transformation in water bodies. The published results revealed that the elevated CO2 would reduce the water pH, increase CO2 and HCO3- concentrations, but with different effects on the nitrification and denitrification between eutrophic and oligotrophic water. Elevated atmospheric CO2 could inhibit nitrification and denitrification in oligotrophic water, thereby reduce N2O flux from water. The nitrification process in the eutrophic water bodies was also inhibited, but its denitrification might be promoted by the elevated CO2. In the eutrophic water bodies, there could be an increase of N2O flux when pH was maintained in the range of 7-9. These might eventually result in the accumulation of NH4+ and reduction of NO3- in water, producing an impact on the microbial diversity. Based on these reviews, we proposed some research gaps related to the relevant research fields as well as some scientific questions that is worth to be further explored. This review would be helpful to better understanding on how the greenhouse effect caused by the elevated atmospheric CO2 would affect nitrogen cycle in aquatic ecosystem.

Research progress on the underlying mechanisms of plant defense enzymes in response to pest stress

GUO Zu-guo, WANG Meng-xin, CUI Lin, HAN Bao-yu
Chinese Journal of Applied Ecology. 2018, 29 (12): 4248 doi: 10.13287/j.1001-9332.201812.036
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Plants respond to herbivory through a series of physiological and biochemical defense mechanisms to counter the stress of herbivorous pests, including the dramatic changes in activities of various defense enzymes. Here, we reviewed the recent research progress on the response mechanisms of six common plant defense enzymes, SOD, CAT, POD, PPO, LOX and PAL, to insect stress, and compared their similarities and disparities. We sorted out their interactive sequences in response to the insect stress and analyzed the changes of defense enzyme activities and their associations with defense enzyme genes after being attacked by pests. Finally, we discussed the key problems/challenges in this area and proposed the prospects for studying the mechanisms of plant defense enzymes.
Research paper

Effect of naturally restored grassland on the ephemeral gully erosion in the loess hilly and gully region

WANG Wen-xin, WANG Wen-long, KANG Hong-liang, GUO Ming-ming, YANG Bo, CHEN Zhuo-xin, ZHAO Man
Chinese Journal of Applied Ecology. 2018, 29 (12): 3891 doi: 10.13287/j.1001-9332.201812.016
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Ephemeral gully erosion is an important erosion type in hilly and gully regions of Loess Plateau. While previous studies mainly focused on ephemeral gullies in agricultural land, little is known about the effects of naturally restored grassland on ephemeral gully erosion. In this study, taking the bare ephemeral gullies as the baseline, we conducted in-situ flushing tests to explore runoff and sediment yield characteristics and erosion mechanism of grassland ephemeral gullies under the runoff conditions of 5, 10, 15, 20 and 25 L·min-1. Compared to the bare ephemeral gully, average flow velocity, stable runoff rate, Reynolds number and Froude number of grassland ephe-meral gullies was reduced by 25.4%-67.3%, 8.4%-26.6%, 54.9%-80.5%, 18.6%-65.1%, respectively, whereas resistance coefficient was increased by 0.09-7.18 folds. Compared to the bare ephemeral gully, the maximum sediment yield rate, stable sediment yield rate, average sediment yield rate of grassland ephemeral gullies was decreased by 55.1%-90.9%, 61.8%-95.4%, and 64.8%-92.4%, respectively. The sediment yield reduction benefit of the naturally restored grassland under the discharge flow rate of 5-25 L·min-1 could reach 65.9%-88.8%, which decreased with increasing discharge flow rate. Compared to the bare ephemeral gully, average stream power and average shear stress of grassland ephemeral gullies was reduced by 54.9%-80.5% and 12.4%-51.1%, respectively, whereas the critical stream power and critical shear stress was increased by 1.43 folds and 33.7%, respectively. The average sediment yield of grassland and bare ephemeral gullies was signifi-cantly linearly related to average stream power and shear stress. Naturally restored grassland significantly increased the erosion resistance and reduced runoff erosion potential of ephemeral gullies.

Variations of organic carbon storage in vegetation-soil systems during vegetation degradation in the Gahai wetland, China

MA Wei-wei, WANG Yue-si, LI Guang, WU Jiang-qi, LUO Yong-zhong, CHEN Guo-peng
Chinese Journal of Applied Ecology. 2018, 29 (12): 3900 doi: 10.13287/j.1001-9332.201812.003
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Qinghai-Tibet Plateau wetland, an important component of terrestrial ecosystem, plays an essential role in global carbon cycling. To understand the variation of organic carbon storage in vegetation-soil system during vegetation degradation in the Gahai wetland we examined aboveground litter, root biomass and soil organic carbon content in different degradation stages (CK: no degradation, SD: light degradation, MD: moderate degradation, HD: heavy degradation). The results showed that except for HD, carbon storage of aboveground biomass was 99.58-205.64 g·m-2 and that of root biomass (0-40 cm) was 56.96-754.37 g·m-2. The carbon stocks of aboveground and roots decreased significantly with degradation. Soil bulk density increased first and then decreased with degradation. Soil bulk density of each layer under degraded wetland was greater than that of the control. The carbon storage of litter was 17.29-35.69 g·m-2, which was significantly higher in CK than in MD and HD. The carbon storage in the soil (0-40 cm) was 7265.06-9604.30 g·m-2, with the order of MD>CK>SD>HD. The carbon storage in CK and MD as significantly higher than that in SD and HD. The total carbon storage in the vegetation-soil system was 7265.06-10389.94 g·m-2 under different degradation stages. The largest was in CK, followed by MD, SD, and HD. Organic carbon was mostly stored in soil, which accounted for over 90% of the storage. Moderate interference might benefit carbon sequestration of the alpine wetland ecosystems.

Effect of vegetation utilization on runoff and sediment production on grain-for-green slopes in the wind-water erosion crisscross region

WANG Zi-hao, ZHANG Feng-bao, YANG Ming-yi, REN Rui-xue, DENG Xin-xin, CAO Xiao-juan, LI Zhan-bin
Chinese Journal of Applied Ecology. 2018, 29 (12): 3907 doi: 10.13287/j.1001-9332.201812.014
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To effectively utilize the vegetation on grain-for-green slopes in the wind-water erosion crisscross region, it is necessary to determine the reasonable vegetation utilization intensity. We set up runoff plots on slopes which were not cultivated and were closed for many years in the Liudaogou catchment, a typical catchment in wind-water erosion crisscross region of the Loess Plateau. With artificial simulated rainfall experiments, the characteristics of runoff and sediment yield on slopes (10°, 20° and 30°) under different utilization intensity of vegetation were studied to select the reasonable utilization intensity. The results showed that the runoff rate in the process of rainfall simulation could be divided into two periods: rapidly increasing in the initial period and slow increasing or quasi-steady state in the middle and late periods. The variation of erosion rate during the rainfall was dependent on the slope. The utilization intensity had a significant effect on the runoff yield, which increased with the increasing utilization intensities. The slope gradient had a significant effect on the sediment yield, with the variation of sediment yield with slope gradient being: 20°>30°>10°. Compared with the unused (natural) plots, the relative runoff and sediment increased with increasing utilization intensities. Predicted based on the rainfall data, annual soil erosion amount on the slope would be basically lower than the tolerance level of soil loss when the vegetation cover on the slope surface reached 25% in 15 years after abandoning reclamation. More attention should be paid to the restoration and management of vegetation on the slope of 20° in this area.

Niche of main woody plant populations of Pterocarya stenoptera community in riparian zone of Lijiang River, China

LIU Run-hong, CHANG Bin, RONG Chun-yan, JIANG Yong, YANG Rui-an, LIU Xing-tong, ZENG Hui-fang, FU Gui-huan
Chinese Journal of Applied Ecology. 2018, 29 (12): 3917 doi: 10.13287/j.1001-9332.201812.001
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To understand the niche characteristics of main woody species in Pterocarya stenoptera community, we investigated P. stenoptera communities in riparian zone of Lijiang River, China. The niche characteristics of main species in tree layers and shrub layers were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarities and Pianka niche overlap. The results showed that P. stenoptera in the tree layer, and Ficus abelii and Morus alba in the shrub layer had higher niche breadth than other species. The species with larger importance values generally had larger niche breadth, but the rank orders of which were not exactly the same. The niche similarity of main populations in the tree layer was generally smaller than that in the shrub layer. The mean value of niche similarity of main populations in the tree layer and shrub layer was 0.151 and 0.236, respectively. There was a low degree of niche similarity among species within the community, indicating that they had a low similarity in resource use. The niche overlap of main populations in the tree layer was generally smaller than that in the shrub layer, with the mean value of niche overlap of main populations in the tree layer and shrub layer being 0.217 and 0.273, respectively. The niche overlap between the main species in the community was relatively lower. There was no significant correlation between niche breadth and niche similarity. The species with larger niche breadth often had more opportunities to overlap with other species. However, their overlap value was not necessarily larger. Larger niche similarity was often associated with higher degrees of niche overlap. The P. stenoptera community in riparian zone of Lijiang River was the climax community, the relationship among species was relatively stable, the population regeneration was very slow, and the development trend of this community was declining in the future.

Temporal and spatial distributions of fine roots of different varieties of Camellia oleifera

LIU Jun-ping, LIU Gang, YOU Lu, YU Su-qin, LIAN Lu-nan, WANG Han-kun, YAN Meng, HU Dong-nan
Chinese Journal of Applied Ecology. 2018, 29 (12): 3927 doi: 10.13287/j.1001-9332.201812.027
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We examined fine root distribution dynamics at the depth of 0-40 cm soil profile for five varieties of Camellia oleifera, including “Ganwu 1”, “Ganyong 5”, “Changlin 4”, “Changlin 40” and “Gan 447”, in one year using minirhizotron technique. The temporal and spatial distribution characteristics of total root tip number (TRT), average root length density (ARLD) and average root diameter (ARD) were analyzed. The results showed that the TRT and ARLD changes of each variety were relatively stable in the second half of 2016, while there was a significant monthly fluctuation in the first half of 2017, especially for “Ganwu 1” and “Changlin 40”. The TRT and ARLD of “Ganwu 1” peaked in May 2017, while the ARD of “Changlin 4” peaked in March 2017. The TRT and ARLD values of “Ganwu 1” and the ARD value of “Changlin 4” were significantly greater than those of other varieties during the whole observation period. The spatial distribution and monthly dynamics of fine roots varied significantly among different varieties of Camellia oleifera. The fine roots were mainly distributed at the soil layer of 0-20 cm for “Ganwu 1” and“ Gan 447 ”, but at 20-40 cm for “ Changlin 4 ”and “ Changlin 40 ”. The latter two varieties had relatively stable spatial distribution and monthly dynamics of fine roots when compared to others. In contrast, the root biomass of “Ganyong 5” was not significantly different between both soil layers despite a large spatial variation. The ARD of “Changlin 4” was significantly larger at the soil layer of 20-40 cm than that of 0-20 cm. There was no significant difference in ARD between both soil layers for other varieties. In conclusion, within the five varieties, “Ganwu 1” had the greatest biomass of fine roots, which were mainly distributed in the upper soil layer, while “Changlin 4” had the largest diameter of fine roots, which were mainly distributed in the lower soil layer.

Elevational variations of leaf stochiometry in Leontopodium leontopodioides on the Qinghai-Tibetan Plateau, China

XU Xue-yun, QIN Yan-yan, CAO Jian-jun, LI Meng-tian, GONG Yi-fan, ZHANG Xiao-fang
Chinese Journal of Applied Ecology. 2018, 29 (12): 3934 doi: 10.13287/j.1001-9332.201812.021
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Topography has major impacts on the trade-off of plant survival strategies. Exploring the differential pattern of leaf ecological stoichiometry along the elevation gradient contributes to a better understanding of plant’s response to environmental changes and its ecological adaptability. We investigated leaf C, N, and P concentrations and stoichiometric ratios of Leontopodium leontopodioides at three elevations, including from 4400 m to 4700 m, from 4701 m to 5000 m, and from 5001 m to 5300 m, on the northeastern margin of the Qinghai-Tibetan Plateau in China. The results showed that the concentrations of leaf C, N, and P of L. leontopodioides were 405.36 g·kg-1, 18.42 g·kg-1 and 0.94 g·kg-1, respectively. Leaf C/N, C/P, and N/P were 22.67, 467.61 and 20.30, respectively. The concentrations of leaf N and P of L. leontopodioides consistently increased with the increases of elevation. The coefficient of variations for leaf C, N and P concentrations and ratios of L. leontopodioides were all less than 30%, with an order of P (30%) > C/P (29%) > C/N (18%) > N (17%) > N/P (15%) > C (3%). The growth of L. leontopodioides on the Qinghai-Tibetan Plateau was mainly limited by P availability.

Characteristics of soil phosphorus fractions under different thinning intensities in Larix principis-rupprechtii plantation and the affecting factors

LIU Xu-jun, CHENG Xiao-qin, TIAN Hui-xia, JIA Xiao-dong, HAN Hai-rong
Chinese Journal of Applied Ecology. 2018, 29 (12): 3941 doi: 10.13287/j.1001-9332.201812.029
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Thinning is an important plantation management strategy. Phosphorus (P) is one of the limiting nutrients in forest ecosystems. The impacts of thinning on soil P remain unclear. In this study, we investigated the characteristics of soil P fractions in topsoil (0-10 cm) of Larix principis-rupprechtii plantation in Taiyue Mountain, Shanxi Province under different thinning intensity (control, CK, 0%; low thinning, LT, 15%; moderate thinning, MT, 35%; high thinning, HT, 50%) and the affecting factors. The soil P fractions were measured using Tissen modified Hedley P fractionation method. The results showed that the total inorganic P content in soil was significantly higher in stands subjected to moderate thinning than in control. The soil acid phosphatase activity (APA) and the contents of Resin-Pi, NaHCO3-Pi, NaHCO3-Po, NaOH-Pi, and microbial biomass phosphorus (MBP) were significantly increased in LT and MT compared with CK, but the content of NaOH-Po showed an opposite trend. Thinning had no significant effect on soil total P, total organic P, non-available P and residual-P. Soil moisture, organic matter, MBP and APA were the important factors affecting soil P availability. Our results demonstrated that MT could enhance soil P availability in Larix principis-rupprechtii plantation.

Effects of NaCl stress on stomatal traits, leaf gas exchange parameters, and biomass of two tomato cultivars

GUO Li-li, HAO Li-hua, JIA Hui-hui, LI Fei, ZHANG Xi-xi, CAO Xu, XU Ming, ZHENG Yun-pu
Chinese Journal of Applied Ecology. 2018, 29 (12): 3949 doi: 10.13287/j.1001-9332.201812.022
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To understand the mechanism underlying responses of stomatal traits, gas exchange parameters, and biomass of tomato plants to salt stress, two tomato cultivars (Shed and Alam) were treated by salt stress by adding NaCl (0.1 mol·L-1) to nutrition medium in environmental growth chambers for 90 days. Our results showed that salt stress substantially decreased the stomatal density, stomatal width, stomatal area, and stomatal area index of Shed by 32%, 45%, 25%, and 49%, respectively. The stomatal traits of Alam were not affected by NaCl treatment. The spatial scales of the regular stomatal distribution pattern of Shed and Alam were significantly decreased by 30% and 43%, and the nearest neighbor distance Lhat (d) of shed cultivar was increased by 20% under salt stress. NaCl stress resulted in marginal declines in the net photosynthetic rates (Pn), stomatal conductance (gs), transpiration rates (Tr) of both cultivars. The decrease of the photosynthetic rate of Shed under salt stress resulted from stomatal limitation, whereas the Pn of Alam was subjected to non-stomatal constraints. NaCl stress substantially decreased the seedling biomass of both cultivars, and the decline of belowground biomass was higher than that of aboveground biomass. Overall, our results suggested that the Alam cultivar is more salt-tolerant than Shed.

Prediction models and the extrapolation effects for water content of surface dead fuels in the typical stand of the Great Xing’an Mountains of China by one-hour time step

YU Hong-zhou, SHU Li-fu, DENG Ji-feng, YANG Guang, LIANG Qi, LI Jing-hao, ZHU Hang-yong
Chinese Journal of Applied Ecology. 2018, 29 (12): 3959 doi: 10.13287/j.1001-9332.201812.008
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The water content of surface dead fuels is one of the most important indicators for forecasting fire danger and fire behaviors. We employed the timelag equilibrium water content methods (i.e. Nelson and Simard models) and the meteorological variable regression method to continuously measure the water content of surface dead fuels by one-hour time step from September to October in 2010 under Populus davidiana + Betula platyphylla, Picea koraiensis and the cutover lands (Pinus sylvestris var. mongolica + Betula platyphylla) with different canopy densities in Pangu Forestry Bureau, the Great Xing’an Mountains, Heilongjiang Province, China. We established prediction models and obtained prediction errors. The models were also used to extrapolate the water contents of surface dead fuels under other forest stands and the extrapolation accuracy was analyzed. The results showed that the mean absolute error, the mean relative error and the mean square error root of Nelson model (0.0154, 0.104 and 0.0226) were lower than those of Simard model (0.0185, 0.117 and 0.0256). In terms of extrapolation effects, the mean absolute error, the mean relative error and the mean square error root of meteorological variable regression method (0.0410, 0.0300 and 0.0740) were lower than those of Simard model (0.610, 0.492 and 0.846), but they were higher than those of Nelson model (0.034, 0.021 and 0.0660). Such results indicated that the timelag equilibrium moisture content method by one-hour time step, especially Nelson model, was sui-table for the forest stands in the Great Xing’an Mountains. Although extrapolation could not reduce the prediction errors, it could help improve the prediction accuracy and the efficiency of the present models applied to different forest stands or in a larger scale. The modeling and extrapolation errors were closely related to species identity and canopy densities, thus the appropriate timelag equilibrium moisture content methods should be selected according to different forest stands and locations.

Variation of soil bacterial diversity after the invasion of Phyllostachys edulis into Pinus massoniana forest

LI Wei-cheng, SHENG Hai-yan, CHEN Wei-jie, LIU Yao-yao, ZHANG Rui, WEN Xing
Chinese Journal of Applied Ecology. 2018, 29 (12): 3969 doi: 10.13287/j.1001-9332.201812.002
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To identify the variation in soil bacterial community diversity brought by the invasion of Phyllostachys edulis into Pinus massoniana forest, we collected mixed soil samples from three types of forests, including a pure Ph. edulis forest, a mixed Ph. edulis and conifers (P. massoniana) fore-st, and a mixed forest of evergreen broadleaves and conifers. Samples were analyzed by high-throughput sequencing for measuring the soil bacterial community diversity and structure. The results showed that the bacterial communities comprised of 511 genera, 160 families, 134 orders, 88 classes, and 39 phyla. The proportion of Acidobateria in the pure Ph. edulis forest was significantly lower and the proportions of Actinobacteria, Bacteroidetes, TM7, and Chlamydiae were significantly higher than that in other forests. Meanwhile, various genera showed significant differences in proportions in both the mixed forests when compared with their corresponding proportions in the pure Ph. edulis forest. There were 130 non-dominant genera presented alone in each of the two mixed forests, at proportions between 0.005% and 0.1%. The pure Ph. edulis forest had the lowest α diversity, while that of the mixed Ph. edulis and evergreen broadleaf forest was intermediate, and that of the mixed evergreen broadleaf and coniferous forest was the highest. The index of α diversity followed evergreen coniferous mixed forest > bamboo needle mixed forest > pure bamboo forest, and the diffe-rence between the mixed Ph. edulis and evergreen broadleaf forest and the mixed evergreen broadleaf and coniferous forest was insignificant. The PCoA results revealed that the invasion of Ph. edulis affected the population diversity and community structure of soil bacteria. There was a significant correlation between the percentage of non-dominant bacterial phyla in the soil (less than 0.1% of the proportion) and the soil environmental gradient such as water-soluble organic nitrogen and nitrate. Water-soluble organic nitrogen and nitrate had strong effects on the non-dominant bacterial population in the soil following the invasion of Ph. edulis into the P. massoniana forest. These findings would serve as important references for further related studies.

Effects of decay level of fallen trees and their formed microsite types on soil physicochemical properties in a spruce-fir forest

DUAN Wen-biao, QU Mei-xue, CHEN Li-xin, ZHANG Yu-shuang, LI Shao-bo, DUAN Wen-jing
Chinese Journal of Applied Ecology. 2018, 29 (12): 3977 doi: 10.13287/j.1001-9332.201812.030
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To reveal the effects of decay level of fallen trees and their formed microsite types on soil physicochemical properties, the differences in soil physicochemical properties (bulk density, capillary porosity, total porosity, capillary water holding capacity, saturated moisture capacity, soil organic carbon, total nitrogen, total phosphorous, available phosphorous, available potassium, and pH) and stoichiometry (C/N, N/P, and C/P) among different decay levels of treefalls and between different microsite types in the formed gaps by fallen trees were analyzed in a spruce-fir fore-st in a valley of Liangshui National Nature Reserve in Xiaoxing’ an Mountains. The results showed that the effects of the decay levels of fallen trees on soil physical properties was not significant. In contrast, we found significant effects of the formed microsite types in soil physical properties. Except for saturated soil water holding capacity, the other soil physical properties were the best under the fallen trees and the worst in the pit bottom. Except of available phosphorus, the contents of the other soil nutrients exhibited a significant increase trend with the increasing decay levels of fallen trees. Among three microsites, the contents of soil nutrients were the lowest and pH were highest in the pit. As for the shallow soil layer, C/N, N/P and C/P of three microsites decreased with the increasing decay levels of fallen trees, while C/N in mound top and in pit bottom increased, N/P and C/P decreased, and the variation of C/P was consistent with that of available phosphorus. In conclusion, with the increasing decay levels of fallen trees, the contents of soil nutrients were signifi-cantly increased. There are significant differences of soil nutrients among different microsites, with the lowest values in the pit.

Forest tree species identification and its response to spatial scale based on multispectral and multi-resolution remotely sensed data

XU Kai-jian, TIAN Qing-jiu, YUE Ji-bo, TANG Shao-fei
Chinese Journal of Applied Ecology. 2018, 29 (12): 3986 doi: 10.13287/j.1001-9332.201812.011
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The effect of spatial scale could not be ignored in identification results of forest types generated by multi-resolution images, and the influence of adding texture information from remote sensing data on the accuracy of forest trees species identification at different spatial resolutions has not been clearly addressed. To clarify this situation, we studied the Wangyedian forest farm in Northeast China, by using quasi-synchronous and geographical coordinate matched multi-resolution satellite observations (six spatial resolution levels: 1, 2, 4, 8, 16 and 30 m) which were supported with GF-1 PMS (pan and multi-spectra sensor), GF-2 PMS, GF-1 WFV (wide field view) and Landsat-8 OLI (operational land imager) and could investigate any possible correlations between spatial resolution and the recognition result, besides the influence of adding texture information. Five dominant tree species were classified and identified using Support Vector Machine (SVM) classifier. We also examined the identification results of the dominant forest trees species obtained by using the up-scaling algorithm. The results showed that overall classification accuracy of tree species was significantly influenced by the spatial resolution of images. The highest accuracy at the 4 m resolution, and the accuracy decreased to a minimum as the resolution reduced to 30 m. The addition of texture information increased classification accuracy using multispectral imagery with resolutions from 1 to 8 m, and the overall accuracy of dominant tree species identification created after adding texture information was 2.0%-3.6% higher than that from results of spectral information alone in the study area. However, the improvement of accuracy did not appear to hold for medium resolution imagery (16 and 30 m spatial resolution). In addition, there was a significant difference between the multi-scale classification results provided by up-scaled images and that obtained from native remote-sensing images for each spatial scale. These results indicated that the real satellite images should be used to ensure the accuracy of results when we examine multi-spatial-scale remote sensing observations or applications.

Comparison of object-oriented remote sensing image classification based on different decision trees in forest area

CHEN Li-ping, SUN Yu-jun
Chinese Journal of Applied Ecology. 2018, 29 (12): 3995 doi: 10.13287/j.1001-9332.201812.015
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Geographic Object-Based Image Analysis (GEOBIA) was a product under the background of increasing high-resolution remote sensing data. How to improve the accuracy and efficiency of classification of high-resolution images is one of the important topics in image processing. After objects segmented multiscale by QuickBird image was classified, the efficiency of C5.0, C4.5, and CART decision trees in object-oriented classification of forest areas was analyzed. The accuracy of those three methods were compared with kNN method. The eCognition software was used to multiscale segmentation of remote sensing images, with the result showing that 90 and 40 were the optimal scales. After separating vegetation and non-vegetation at 90 scale, 21 features such as spectrum, texture and shape of different vegetation types were extracted at 40 scale, knowledge mining was carried out by using C5.0, C4.5 and CART decision tree algorithms respectively, and classification rules were automatically established. The vegetation area was classified based on the classification rules and the classification accuracy of different methods was compared. The results showed that the classification accuracy based on decision-tree was higher than that of the traditional kNN method. The accuracy of C5.0 method was the best, with the overall accuracy and Kappa coefficient reaching 90.0% and 0.87, respectively. The decision tree algorithm could effectively improve the accuracy in classification of forest species. The Boosting algorithm of the C5.0 decision tree had the most significant improvement on the classification.

Influence of automatic exposure on the estimation of seasonal variations in leaf area index measured by digital hemispherical photograph

YUAN Zhen-hao, JIN Guang-ze, LIU Zhi-li
Chinese Journal of Applied Ecology. 2018, 29 (12): 4004 doi: 10.13287/j.1001-9332.201812.017
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Automatic exposure is one of the important error sources during measurement of leaf area index (LAI) by digital hemispherical photography (DHP). This study was conducted in a mixed broadleaved-Korean pine (Pinus koraiensis) forest, a secondary birch (Betula platyphylla) forest, a Korean pine plantation and a Dahurian larch (Larix gmelinii) plantation in the Xiaoxing’an Mountains. LAI was measured using DHP and LAI-2200 plant canopy analyzer in the middle of June to September. We compared LAI values measured through these two methods, and then tested whether the forest type and study period had a significant influence on the correlations between the measured values of those two methods. We constructed empirical models for correcting the errors caused by automatic exposure for LAI values measured through DHP at different study periods in different forest types. The results showed that LAI from DHP was underestimated by 20%-49% rela-tive to that from LAI-2200 in four study periods of the four forest types. Forest type had no significant effect on the construction of empirical models between these two measuring methods of LAI, whereas study period showed significant effects. Two classified empirical models (A and B) were constructed, which were suitable for correcting the LAI from DHP in June and September, July and August in four forest types, respectively. After being corrected by the classified empirical models, LAI from DHP of the four forest types increased by 45%-79%, and the measurement accuracy could be improved to 83%-94%. Classified empirical models between LAI from DHP and LAI-2200 could effectively correct the influence of automatic exposure on DHP and greatly improve its mea-surement accuracy, and provide a technical support for rapid and effective measurement of seasonal changes of LAI in different forest types.

Impacts of climate change on climatic division for double cropping rice in Guangdong Pro-vince, China

DU Yao-dong, SHEN Ping, WANG Hua, TANG Xiang-ru, ZHAO Hua
Chinese Journal of Applied Ecology. 2018, 29 (12): 4013 doi: 10.13287/j.1001-9332.201812.041
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Based on the dataset of air temperature from 86 stations during 1961 to 2016, and DEM data derived from 1:250000 topographic maps, we analyzed the spatial-temporal changes of key climatic factors (safe period for double cropping rice, ≥10 ℃ active accumulated temperature) using the methods of linear regression, accumulative anomaly, and inverse distance weighted interpolation. The impacts of climate change on climatic division for double cropping rice was studied by combining with the changes of key climate factors for the periods of 1961-1990, 1971-2000, 1981-2010, before (1961-1997) and after (1998-2016) climatic mutation. The results showed that spatial distributions of safe period for double cropping rice and ≥10 ℃ active accumulated temperature were different from place to place in Guangdong. Generally, they were more or higher in south than in north part, in plain than in mountain regions. Under the background of global warming, the safe period for double cropping rice and ≥10 ℃ active accumulated tempera-ture showed a significantly increasing trend with the rate of 1.7 d and 43 ℃·d per decade, respectively. All climatic factor had mutation in the year of 1997. According to the climatic conditions of various maturing rice growth and development, climatic zoning for double cropping rice in Guangdong could be divided into three regions: early maturity with early maturity, early maturity with late maturity, late maturity with late maturity. Those regions were distributed in middle-subtropics of northern Guangdong, south-subtropics of middle Guangdong, and north-tropics of southern Guangdong, respectively. Due to the climate change, the area of late maturity with late maturity significantly increased, the area of early maturity with late maturity significantly decreased, and the area of early maturity with early maturity showed no significant change. Relative to that in 1961-1990, the areas of late maturity with late maturity in 1971-2000 and 1981-2010 increased 1.22×106 hm2 and 2.56×106 hm2, respectively, but the area of early maturity with late maturity decreased 1.13×106 hm2 and 2.56×106 hm2, respectively. The area of late maturity with late maturity was more than doubled, but that of early maturity with late maturity decreased about a half after 1997 than that before in Guangdong.

Effects of conservational tillage on water characteristics in dryland farm of central Gansu, Northwest China

PENG Zheng-kai, LI Ling-ling, XIE Jun-hong, KANG Cai-rui, ESSEL Eunice, WANG Jin-bin, XIE Jian-hui, SHEN Ji-cheng
Chinese Journal of Applied Ecology. 2018, 29 (12): 4022 doi: 10.13287/j.1001-9332.201812.007
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Productivity is low and unstable in dryland farms of central Gansu, Northwest China. Conservational tillage is an important way for the sustainable development of agriculture. The effects of different tillage measures on soil moisture infiltration, evaporation, crop yield and water use efficiency (WUE) were investigated in this study based on a long-term experiment since 2001 in Longzhong. There were six treatments, i.e. conventional tillage with no straw (T), no-till with straw cover (NTS), no-till with no straw cover (NT), conventional tillage with straw incorporated (TS), conventional tillage with plastic mulch (TP), and no-till with plastic mulch (NTP), with annual rotation of spring wheat and pea. The results showed that compared with T, soil bulk density of NTS decreased and total porosity of soil increased significantly in wheat and pea land. Compared with conventional tillage, conservation tillage reduced soil infiltration rate in 0-5 cm in the pea field by 56.2%. Conservational tillage siginificantly increased soil saturated water conductivity in both wheat and pea lands. Compared with T, the saturated water conductivity in NTS was significantly increased by 52.8%-107.1%. Conservational tillage siginificantly reduced soil evaporation during growing season. Compared with T, the evapotranspiration of NTP, TP and NTS was significantly reduced by 14.4%-50.8%. The soil evaporation after rain was also decreased. Conservational tillage improved crop yield and water use efficiency by 9.5%-62.8% and 0.4%-50.9%, respectively. Therefore, conservational tillage could increase water use efficiency and crop yield in dryland farming area of central Gansu, Northwest China.

Occurrence characteristics of Echinochloa and its response to long-term fertilization in paddy fields of yellow soil

HUANG Xing-cheng, LI Yu, YE Zhao-chun, BAI Yi-jing, LIU Yan-ling, ZHANG Ya-rong, ZHANG Wen-an, JIANG Tai-ming
Chinese Journal of Applied Ecology. 2018, 29 (12): 4029 doi: 10.13287/j.1001-9332.201812.024
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We studied the characteristics of Echinochloa and its response to variation of rice yield and soil properties under long-term fertilization in paddy field of yellow soil, based on a 23-year long-term fertilization experiment in Scientific Oberving and Experimental Station of Arable Land Conservation and Agricultural Environment (Guizhou), Ministry of Agriculture. The occurrence characteristics of Echinochloa (density, panicle number per plant, totle panicles, seed number per panicle, 1000-seed mass and seed mass per panicle) of ten treatments including CK, N, PK, NK, NP, NPK, 1/4MNP, 1/2MNP, M (manure), MNPK were examined. The results showed that the characteristics of Echinochloa significantly varied with long-term different fertilization. The highest density, panicle number per plant and total panicles of Echinochloa were attained in the MNPK treatment, followed by the 1/4MNP treatment. Compared with the NPK treatment, the density of Echinochloa was significantly decreased in no fertilizer treatment (CK) and unbalanced chemical fertilizer treatments (N, PK, NK, NP). The panicle number per plant significantly increased in organic fertilizer treatments (1/4MNP, 1/2MNP, M, MNPK). Both the density and total panicles of Echinochloa were positively correlated with rice yield. The occurrence characteristics of Echinochloa were positively correlated with soil organic matter, total N, total P, available N, available P and available K. Results from path analysis showed that soil total N had a direct positive effect on panicle number per plant and soil total P content was the main factor affecting the density and total panicles of Echinochloa. Soil available K content was the factor with strongest influence on seed number per panicle and seed mass per panicle. We concluded that the occurrence characteristics of Echinochloa varied with long-term different fertilization. The density, panicle number per plant and total panicles of Echinochloa could be increased with appling cow manure. Soil total P was the direct influencing factor for the variation of density and total panicle of Echinochloa in paddy field of yellow soil.

Simulation of crop growth curve and analysis of interspecific interaction in wheat and faba bean intercropping system

BAI Wen-lian, ZHANG Meng-yao, REN Jia-bing, TANG Li, ZHENG Yi, XIAO Jing-xiu
Chinese Journal of Applied Ecology. 2018, 29 (12): 4037 doi: 10.13287/j.1001-9332.201812.026
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Interspecific interactions are closely related to the intercropping yield advantage. Little attention was paid to the dynamic changes of interspecific interactions. In this study, the growth curves of wheat and faba bean under different planting patterns (wheat monocropped, faba bean monocropped, and wheat and faba bean intercropping) and phosphorus (P) fertilization levels [P0, 0 kg P2O5·hm-2(the control); P1, 45 kg P2O5·hm-2; P2, 90 kg P2O5·hm-2, repetitively] were simulated by Logistic analysis in a two-year field experiment. The dynamics of interspecific interaction were analyzed. The results showed that wheat yield was increased by 10.5%-18.6% when wheat was intercropped with faba bean as compared to monocropped wheat (MW). The yield of intercropping faba bean (IF) was decreased by 4.8%-12.3% relative to monocropped faba bean (MF). However, wheat and faba bean intercropping still showed yield advantage, with the values of land equivalent ratio (LER) and relative crowding coefficient (K) being 1.01-1.15 and 1.12-3.20, respectively. Both the yields and key growth parameters for wheat and faba bean were regulated by P level, but LER and K were not affected by P level. The maximum growth rate (Rmax) and the initial growth rate (r) of wheat were increased by 21.8%-38.7% and 20.8%-38.9% when wheat was intercropped with faba bean as compared to corresponding MW, respectively. The planting pattern had no effect on the key growth parameters of faba bean. No difference in growth curve between monocropping and intercropping crop was found under different P fertilization levels during the early growth stages. The interspecific competition was dominant in wheat and faba bean intercropping system during the early growth stages, without any intercroping biomass advantage (LER<1, K<1). Increased growth rate and decreased intraspecific competitive pressure for wheat were observed when faba bean attaining its maximum growth rate (Tmax) in intercropping system, with both intercropping biomass and yield advantage (LER>1, K>1). In conclusion, the interaction between wheat and faba bean varied with growth stages. Wheat and faba bean intercropping stimulated the growth rate of wheat during the middle and late growth stages, which was a foundation for intercropping advantage.

Relationship of crop yield and soil organic carbon and nitrogen under long term fertilization in black loessial soil region on the Loess Plateau in China

E Sheng-zhe, DING Ning-ping, LI Li-li, YUAN Jin-hua, CHE Zong-xian, ZHOU Hai-yan, SHANG Lai-gui
Chinese Journal of Applied Ecology. 2018, 29 (12): 4047 doi: 10.13287/j.1001-9332.201812.028
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The feedbacks between crop yield and soil organic carbon and total nitrogen contents were examined in a long-term experiment, which was established on black loessial soil on the Loess Pla-teau in China. There were six treatments, including CK (no fertilizer), N (single nitrogen fertilizer), NP (chemical fertilizers NP), SNP (straw and chemical fertilizers NP), M (organic manure) and MNP (organic manure and chemical fertilizers NP). Results showed that balanced application of chemical fertilizers, single application of organic manure, the combined application of chemical fertilizers with organic manure and chemical fertilizers coupled with straw returning to the field all significantly increased crop yield and its stability compared with control (CK). The yields of maize and wheat in NP, SNP, M and MNP treatments increased by 92%, 97%, 93%, 141% and 147%, 164%, 139%, 214%, respectively, compared with the control. The annual mean yields of maize and wheat in NP treatment were equal to or higher than those of the local conventional fertilization practices and quite stable among different years, which indicated that the fertilization rates with N 90 kg·hm-2 and P2O5 75 kg·hm-2 were enough for crop growth in wheat-maize rotation system. Application of chemical fertilizer P every other year combined with straw returning to the field (SNP) had similar crop yield values with NP treatment, with the P application amount could be reduced by 50%. The balanced application of chemical fertilizers, organic manure application, the combined application of chemical fertilizers with organic manure, and chemical fertilizers coupled with straw returning to the field could significantly increase soil organic carbon content, whereas chemical fertilizer application had no significant influence on soil total nitrogen content. Across all treatments, the contents of soil organic carbon and total nitrogen were significantly and positively correlated. Under different fertilization treatments, organic carbon sequestration rate was between 15% and 41%. In SNP treatment, the soil organic carbon content enhanced 0.06 g·kg-1 when the amount of organic carbon input every increased 1 t·hm-2, while in CK, N, NP, M and MNP treatments, the increments was between 0.12 and 0.15 g·kg-1. The yields of both maize and wheat were positively correlated with soil total nitrogen content. Maize yield constantly increased with the increases of soil organic carbon content, but wheat yield increased at first and then kept stable with the increases of soil organic carbon content, with a threshold of 6.8 g·kg-1. In conclusion, long-term balanced application of chemical fertilizers, organic manure application, chemical fertilizers combined with manure and chemical fertilizers coupled with straw returning to the field could significantly increase soil organic carbon and total nitrogen contents, consequently resulted in higher crop yield and stubble amount returned to soil, the increase of stubble returned to soil further led to the increase of soil organic carbon and total nitrogen contents, which formed the mutual promotion feedback relationship each other in the black loessial soil region of Loess Plateau in China.

Changes of soil physical and chemical properties of albic soil in the meadow of Sanjiang Plain after rice planting

WANG Qiu-ju, JIAO Feng, LIU Feng, CHANG Ben-chao, JIANG Hui, JIANG Yu, MI Gang, ZHOU Xin
Chinese Journal of Applied Ecology. 2018, 29 (12): 4056 doi: 10.13287/j.1001-9332.201812.005
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The changes and renewal of soil quality are the criteria for judging agricultural development and soil management. The albic soil is the main paddy field soil in Sanjiang Plain. There is limited knowledge about the changes of soil quality after the dry field was changed into the paddy field. Taking albic soils from different years of rice planting as study objects, the changes of soil physical and chemical properties were investigated. The results showed that the total amount of soil organic carbon and reducing substances increased in the ploughing layer (16-23 cm thick) and the bottom ploughing layer (6-8 cm thick). The depth of ploughing layer gradually increased with the increases of rice planting years. There was no significant change after the bottom layer was changed into the paddy field. There was no significant difference in the subsoil layer (20 cm thick) compared with dryland. The Fe2+ and Mn2+ in the soil tended to migrate downward, but only to the plough bottom layer. The ratio of soil solid phase of the ploughing layer and the ploughing bottom layer increased after rice planting, with the ratio of soil solid phase of the ploughing bottom layer increased from 47.8% to 70.0% and the bulk density increased from 1.22 g·cm-3 to 1.77 g·cm-3. Decreases of the total amount of soil porosity, increases of the proportion of micropores, and cohesive leaching deposition in the albic soil were observed after rice planting. The changes of soil physical and chemical properties of albic soil after rice planting were generally consistent with the evolution of paddy soil except for several particularities.

Impact of fertilization on ammonia volatilization and N2O emissions in an open vegetable field

ZHENG Lei, WANG Xue-dong, GUO Li-ping, ZHANG Xin-yue, WANG Dong-yan, NIU Xiao-guang, YUN An-ping, LI Ying-chun
Chinese Journal of Applied Ecology. 2018, 29 (12): 4063 doi: 10.13287/j.1001-9332.201812.023
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A field experiment with different nitrogen fertilization rates and mitigation measures was conducted in an open-ground vegetable field on the North China Plain to investigate the effects of nitrogen application level and management practices on ammonia volatilization and N2O emission. Reducing the nitrogen fertilization rate by 20% and by 50% decreased ammonia volatilization by 25.7% and 48.0%, respectively, during the spring-sowed cucumber growth period. Amendment with combined inhibitors and biochar decreased ammonia volatilization loss by 10.0% and 6.1%, respectively. Reducing nitrogen fertilization rate by 20% and 50% decreased N2O emission by 28.8% and 61.0% during the spring-sowed cucumber growth period. Addition of combined inhibitors decreased N2O emission by 58.9%, while it was increased by 14.1% with biochar addition. Under the same application method of banding application, replacing 30% nitrogen fertili-zer with organic manure did not show any significant mitigation for ammonia volatilization and N2O emission. For the intensively managed vegetable fields, reducing the nitrogen application rate appropriately was the most effective measure to reduce ammonia volatilization and N2O emission.

Effects of yam/leguminous crops intercropping on soil chemical and biological properties of yam field

ZHANG Yue-meng, WANG Qian-zi, SUN Zhi-mei, NIU Shao-bin, LIU Jia, MA Wen-qi, YANG Xiao-zhong
Chinese Journal of Applied Ecology. 2018, 29 (12): 4071 doi: 10.13287/j.1001-9332.201812.025
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We investigated the effects of yam/leguminous crops intercropping on soil chemical and biological properties as well as soil comprehensive fertility in a field experiment. Results showed that compared with the monoculture, both yam/alfalfa and yam/clover intercropping increased the concentrations of nitrate nitrogen (N), available phosphorus (P) and available potassium (K) in the 0-20 cm and 20-40 cm soil layers, while reduced soil pH and electrical conductivity (EC) in early growth period and rhizome rapid expansion period of yam. Intercropping with leguminous crops enhanced the activities of urease, alkaline phosphatase and catalase, and also enhanced soil basal respiration in the 0-20 cm and 20-40 cm soil layers during the whole growth period of yam. There was no influence of intercropping on soil sucrase activity and dehydrogenase activity. The effects of intercropping with leguminous crops on soil fertility at yam harvest were further analyzed by combining the membership function model and principal component analysis. Results showed that intercropping with leguminous crops could significantly increase the soil comprehensive fertility in the 0-20 cm and 20-40 cm soil layers. Therefore, it might be an effective measure to improve soil fertility and environmental quality, as well as alleviate continuous cropping obstacles of yam by yam/leguminous crops intercropping through enhancing soil biological diversity.

Landscape pattern change and its response to anthropogenic disturbance in the Qinling Mountains during 1980 to 2015

GUO Shao-zhuang, BAI Hong-ying, MENG Qing, HUANG Xiao-yue, QI Gui-zeng
Chinese Journal of Applied Ecology. 2018, 29 (12): 4080 doi: 10.13287/j.1001-9332.201812.018
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Understanding landscape pattern change and its response to anthropogenic disturbance is of great significance for ecosystem conservation and management. Based on high-precision land use data from 1980 to 2015, we studied the spatial and temporal changes of landscape patterns in the Qinling Mountains and its response to anthropogenic disturbance by using the landscape pattern vulnerability index and human disturbance degree constructed by the landscape pattern index and the surface coverage classification system. The results showed that the degree of landscape fragmentation gradually increased in the Qinling Mountains. The landscape shape became more complex, the degree of landscape aggregation and connectivity decreased, and the spatial distribution of the landscape pattern index showed distinct features of topographic differentiation from 1980 to 2015. The fragility of the landscape pattern in the Qinling Mountains was on a downward trend as a whole. The spatial pattern of the low-vulnerable region had changed significantly, which mainly expanded from Xi’an and Hanzhong to the surrounding areas. The degree of anthropogenic disturbance in the landscape pattern of Qinling Mountains gradually increased. The spatial distribution was “high in the east, low in the west, high in the north-slope, low in the south-slope, high on the periphery, low in the middle”. The fragility of landscape pattern, patch density and Shannon diversity index increased with the increases of anthropogenic disturbance, while the aggregation index and maximum patch index decreased. In the past 35 years, the impacts of anthropogenic disturbance, which gradually weakened the vulnerability of landscape pattern, also increased Shannon diversity index and the largest patch index gradually, while it had not significantly changed the patch density and the aggregation index.

Simulation of sponge city landscape pattern optimization based on the storm water management model (SWMM)

CHU Ya-qi, ZENG Jian, SHI Yu, XIU Dai-xi
Chinese Journal of Applied Ecology. 2018, 29 (12): 4089 doi: 10.13287/j.1001-9332.201812.020
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With the rapid urbanization and increasing urban impervious areas in China, urban water-logging has become increasingly serious. The concept of sponge city was proposed based on the low impact development (LID) idea. We analyzed the impacts of landscape pattern optimization scenario on urban surface runoff and rainwater control ability in central urban area of Shen-Fu New Town in Liaoning Province. The storm intensity formula was used to construct rainfall process in different return periods. The landscape patterns of the study area were optimized based on sponge city concept. The storm water management model (SWMM) was used to simulate the differences of surface runoff and rainwater regulation ability under the pre-planning scenario and the landscape pattern optimization scenario. The results showed that total runoff and runoff coefficient of the study area were increased with increasing rainfall return period. In the same rainfall return period, the runoff coefficient was significantly reduced. The reduction of total runoff gradually increased, being 2.94, 3.58, 3.72, and 4.19 mm during the 1-year, 3-year, 5-year and 50-year return period under landscape pattern optimization scenario. The corresponding reduction rate was gradually reduced, being 23.9%, 16.4%, 14.3%, and 9.3%, respectively. Landscape pattern optimization scenario could meet the requirements that the rainfall was controlled at 20.8 mm when the rainfall return period p=1 year, the rainwater pipe network would not overload when p=3 years, and the river channel would not overflow when p=50 years.

Integrated assessment of coastal ecological security based on land use change and ecosystem services in the Jiaozhou Bay, Shandong Peninsula, China

ZHENG Yang, YU Ge, ZHONG Ping-li, WANG You-xiao
Chinese Journal of Applied Ecology. 2018, 29 (12): 4097 doi: 10.13287/j.1001-9332.201812.035
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Land use-based development activities can change the quality of coastal environment and the supply pattern of ecosystem services, negatively affecting the ecological security of coastal zones. Coastal ecosystem research has generally used terrestrial ecosystem research models which cannot actually reflect the features of the coastal zone—An independent environmental system combining land and sea. A scientific explanation is lacking for the complex relationship among driving factor of land-based activities, the response of ecosystem services, and the realization of ecological security in the coastal zone. Here, we presented an integrated assessment model for coastal ecological security that was established following the route of “Land use-Ecosystem services-Ecological security” and considering the spatial heterogeneity and mobility of coastal ecosystem services. The proposed model was used to assess the impacts of land use-based activities on coastal ecosystem services and regional ecological security and reveal the associated spatiotemporal variations in the Jiaozhou Bay, Shandong, China. Land use change around Jiaozhou Bay, as the main representation of pressure in the ecological security system, exhibited certain association and tendency with the states of ecosystem services and ecological security in the corresponding sea area. Owing to massive land transfer to built-up lands during urbanization, the ecosystem services declined in the sea areas of Jiaozhou Bay and thus resulted in the deterioration of coastal ecological security. The integrated assessment model of coastal ecological security based on pressure-state-response (PSR) frame could effectively reflect the spatial distribution and trends of coastal ecological security. Meanwhile, this model could clarify the response relationship of ecosystem services and ecological security in the sea portion with the land-based driving factor, i.e., land use, in the coastal ecosystems. Unlike the methods commonly used in previous studies on coastal ecological security, the model established here overcomes the shortcomings of others that only focus on the land portion and ignore the link and interaction between the land and sea. This model was therefore of improvement to the evaluation of coastal ecological security.

Spatial-temporal evolution and prediction of urban landscape pattern and habitat quality based on CA-Markov and InVEST model

CHU Lin, ZHANG Xin-ran, WANG Tian-wei, LI Zhao-xia, CAI Chong-fa
Chinese Journal of Applied Ecology. 2018, 29 (12): 4106 doi: 10.13287/j.1001-9332.201812.013
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The change of urban landscape caused by human activities is one of the most important factors affecting terrestrial ecosystem. The distribution of urban landscape pattern has great impacts on the service function of regional biodiversity. To reveal the variation of landscape pattern and habi-tat quality in cities and its driving factors, we extracted landscape type information of Wuhan in 2005, 2010, 2015, and analyzed spatial-temporal evolution of landscape pattern using Markov transition model. The CA-Markov model was used to simulate the landscape pattern in 2020 under the natural growth scenario. The driving factor for landscape variation was analyzed using Logistic regression model. Combined with InVEST model, spatial pattern of habitat quality and its variation in three phases were calculated and evaluated. The simulated habitat quality in 2020 was obtained and its distribution characteristics were analyzed. The relationship between variation of landscape pattern and human activities was explored. The results showed that cultivated land and manufactured surface were the landscape types with highest variations between 2005 and 2015. The area of cultivated land continued to decline, with most of the area being transferred into manufactured surface. The area of manufactured surface continued to increase, most of which was transferred from paddy field and dry land. From 2005 to 2015, the habitat quality declined, with a large number of landscapes with high habitat quality level being changed to low habitat quality level. The overall index of habitat quality decreased and the biodiversity service function declined, indicating the degeneration of habitat quality. In 2015-2020, the evolutionary trend of landscape pattern and habitat quality would keep consistent with the past decade, with an increasing area of artificial surface, decreasing index of habitat quality, weakening biodiversity service function, and degenerating habitat quality. The most important factor accounted for the landscape pattern change in the study area was the changes in Gross Domestic Product (GPD) and regional fiscal revenue. Human socio-economic activities were the key driving force for the spatial variation of landscape and degeneration of habitat quality. Urbanization and land reclamation by filling lakes were the main reasons for landscape pattern variation in Wuhan.

Coordination of urbanization quality and resource utilization in inclusive perspective: Taking 288 cities in China as an example

YU Wei, ZHAO Lin
Chinese Journal of Applied Ecology. 2018, 29 (12): 4119 doi: 10.13287/j.1001-9332.201812.019
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To explore the coordination between urbanization quality and resource utilization and its influencing factors from the perspective of inclusiveness is conducive to expanding the connotation of urbanization quality, which could provide guidance for improving the quality of urbanization. By integrating the concept of inclusiveness into the connotation of urbanization quality and resource utilization, we analyzed the spatial pattern of the coordination of urbanization quality and resource utilization in 288 cities above prefecture level in China with the GIS technology and coordination degree model, with the potential causes being discussed. The results showed that the inclusive level of China’s urbanization development was low, which was characterized by unequal development opportunities, scattered distribution of high-level cities and large-scale centralized distribution of low-level cities. The overall utilization of resources was at the middle level. The agglomeration chara-cteristics of high- and low-level cities were significant and bounded by Hu Huanyong line. The average coordination degree of urbanization quality and resource utilization was 0.59, which belonged to the medium level, with the grade-difference and the east-west gradient pattern. Urban distribution with high coordination level fitted southeast coastal urban agglomerations well. The distribution of cities above the middle level was in good agreement with that of the “T” type axial belt in China formed by the southeastern coast of China and the Yangtze River economic belt. The lower level cities were concentrated in the middle and upper reaches of the Yellow River, Jiangnan hills, north-west part of the Northeast and Yungui Plateau. The level of urban administration and the level of economic development were positively related to the coordination between urbanization quality and resource utilization. There was a significant correlation between the urban scale and the level of coordination in the city with more than 3 million population.

Index system and method for the evaluation of highway ecological landscape quality: A case study of Nantong City, Jiangsu Province, China

YIN Ming, XIAO Wei, JI Yi-fan, XU Jian-hua, HUA Jian-feng, LU Xiao-li
Chinese Journal of Applied Ecology. 2018, 29 (12): 4128 doi: 10.13287/j.1001-9332.201812.012
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The construction of highway ecological landscape is an important part of highway entity and an iconic feature of scenic countryside and ecological garden city, which plays an important role in the process of achieving social and economic sustainable development. The efficient index system and method is a basic measurement for the assessment of the interior quality and its associated outer environment. By taking five arterial highways (G15, G228, G204, S334 and S335) in the territory of Nantong City, Jiangsu Province as the case, an evaluation system containing quantitative and qualitative indices was developed to deal with the ecological landscape quality. The system composed of 12 evaluation indices which were divided into three categories including ornamental value, ecological efficiency, and safety design. Based on the survey and calculation of the raw data, the variable matrix was established and analyzed with principal component (PC) analysis. The results showed that the equation of highway greening ecological evaluation score was H=0.694×PC1+0.191×PC2+0.115×PC3, and scores of 5 highways ranked in the ordination of G204 > G15 > S334 > G228 > S335. The results would provide methods and references for efficient evaluation of highway landscape.

Landscape pattern evolution along terrain gradient in Fuzhou City, Fujian Province, China

CHEN Zhu, HUANG Ya-bing, ZHU Zhi-peng, ZHENG Qi-quan, QUE Chen-xi, DONG Jian-wen
Chinese Journal of Applied Ecology. 2018, 29 (12): 4135 doi: 10.13287/j.1001-9332.201812.010
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Terrain is an important factor in land landscape pattern change. To reveal the spatial and temporal characteristics and variation of landscape pattern along a terrain gradient, we used three remote sensing images and digital elevation model (DEM) data of Fuzhou in 1995, 2005 and 2015 to investigate the topographic gradient effect of landscape pattern and the cause of formation based on terrain index, land use distribution index, geo-informatics map analysis and landscape index. The results showed that forestland was mainly distributed in middle-low, middle-high and higher level terrain, while farmland, water body, construction land and unused lands were mainly distributed in the low rank terrain. From 1995 to 2015, the area of forestland, farmland, and unused land in Fuzhou decreased, while that of construction land and water body increased. The change of landscape type was stable, which was mainly distributed in middle-low, middle-high, and high grade terrain gradient region. In addition, landscape pattern changes were obvious across the terrain gra-dient. The landscape type of low terrain area mainly shifted to the construction land, but farmland and forestland had an alternation change in the middle-low and middle-high terrain area. The characteristics of landscape pattern fragmentation, landscape heterogeneity and landscape diversity in the study area had been increasing year by year, but they had decreased with the elevation of terrain.

Effects of Epichlo endophytes of Achnatherum sibiricum on spore germination of arbuscular mycorrhizal fungi

Wurihan, LIU Hui, WU Man, REN An-zhi, GAO Yu-bao
Chinese Journal of Applied Ecology. 2018, 29 (12): 4145 doi: 10.13287/j.1001-9332.201812.040
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Endophytic fungi and arbuscular mycorrhizal (AM) fungi are important components of grassland ecosystem. Endophytes can reduce colonization rates of their host plants by AM fungi. In this study, Achnatherum sibiricum, infected by Epichlo sibiricum (Es) or E. gansuensis (Eg), was adopted as experimental material. The effect of Epichlo endophyte culture filtrate, root exudates and aqueous extracts from the leaves (including fresh and dead leaves) on the spore germination rates of AM fungi (Glomus mosseae and Glomus etunicatum) were evaluated. The results showed that culture filtration of Epichlo endophyte significantly inhibited the germination rate of AM fungi spores. Root exudates of infected plants only significantly inhibited the germination of G. etunicatum spores, and such effect was not related to the endophytic species. The leaf aqueous extracts had no significant effect on the germination rate of G. mosseae spores. Only the aqueous extract of Es-infected dead leaves significantly reduced the spore germination rate of G. etunicatum. In natural ecosystem, Epichlo endophytes are normally internally hosted in plants, which may affect the spore germination of AM fungi by affecting the root exudates of the host plants.

Change of community structure of soil mites in the early stage of ecological restoration in moderate rocky desertification of Karst area, Guizhou Province, China

CHEN Hu, JIN Dao-chao, LIN Dan-dan, WANG Peng-ju, ZHOU Zheng
Chinese Journal of Applied Ecology. 2018, 29 (12): 4152 doi: 10.13287/j.1001-9332.201812.032
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The monitoring of soil mite community is an important part of ecological restoration monitoring. Changes of community structure in soil mites could reflect effects of ecological restoration in degraded environment. In different seasons of 2014, we investigated soil mites in the moderate rocky desertification ecological restoration area of Chaoying small watershed in Bijie City, Guizhou Pro-vince. We compared the community structure of soil mites in native Quercus variabilis forest and moderate rocky desertification area. The results showed that soil mites in ecological restoration area of moderate rocky desertification belonged to three orders, 35 families, and 58 genera, with Haploze-tes and Vilhenabates being the dominant genera. Higher number of genera, abundance, and indivi-dual densities were found in upper soil layer. The community structure of predatory Gamasina mites was mainly r-selected, and that of Oribatida mites was mainly Poronota (P-type). In the moderate rocky desertification ecological restoration area, both the abundance and individual density of soil mites were higher than that in moderate rocky desertification area and Q. variabilis forest, while the number of genera, diversity index and richness index were higher than that in moderate rocky desertification area, but lower than that in Q. variabilis forest. On the basis of the control area, 32 genera of mites were recovered and added, accounting for 55.2% of the total number of mite genera in the restoration area. In the whole study area, the number of mite genera were significantly correlated with soil available potassium, richness index, and organic carbon content. The number of indivi-duals, individual density, diversity index, richness index separately had significant correlations with the content of available potassium. The richness index had significant correlation with the content of organic matter. Our results suggested that the vegetation restoration of rocky desertification was beneficial to the restoration of mite community and improvement of soil environment, and that the dominant groups, new groups, and restoration groups of soil mites could indicate environment changes. However, the relationships between soil mite community structure and vegetation, soil physical and chemical factors in the restoration area remained to be further studied.

Effects of antagonistic bacteria B6 against the pathogens of apple replant disease on the biomass of Malus hupehensis Rehd seedlings and soil environment under replanting

LIU Li-ying, DING Wen-long, CAO Ya-jie, YOU Hong-ji, LIU Ke-xin, SUN Zhong-tao, MAO Zhi-quan
Chinese Journal of Applied Ecology. 2018, 29 (12): 4165 doi: 10.13287/j.1001-9332.201812.004
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We isolated strains from the rhizosphere soil of apple trees with replanting disease and evaluated the biological control potential for the pathogens Fusarium proliferatum, F. moniliforme, F. oxysporum, and F. solani. The morphological, physiological and biochemical character, and 16S rDNA sequence of the strain with the highest inhibitory rate were analyzed. The effect of strain biofertilizer on the biomass of Malus hupehensis Rehd. seedlings and soil environment under replanting disease was evaluated in a pot experiment. The results showed that the strain B6 had the strongest antagonistic activity. The inhibitory rate of B6 for F. proliferatum, F. moniliforme, F. oxysporum, Fusarium solani reached 71.8%, 70.1%, 72.6% and 91.5%, respectively. The strain B6 was identified as Bacillus methylotrophicus according to the results of morphological, physiological and biochemical character and 16S rDNA sequence analysis. Compared with the control, the bacterial manure made from the strain B6 enhanced the biomass of Malus hupehensis Rehd. seedlings in replanting soil to different extent. The ground diameter, fresh and dry mass were significantly increased by 18.3%, 49.6% and 51.2%, respectively. The strain B6 dramatically increased the number of cultivable bacteria and actinomyces in replanting soil and reduced the abundance of fungus to 37.7%, which accelerated the conversion of fungal soil to bacterial soil. It also dramatically increased the activities of sucrase, phosphatase, ureaseandcatalase in soil by 37.3%, 24.0%, 42.9% and 49.4%, respectively. In conclusion, the B6 fertilizer could improve the structure of cultivable microbial communities in the continuous cropping soil of apple trees, increase the soil enzyme activity, and enhance the growth of Malus hupehensis seedlings.

Screening and identification of antagonistic actinomycete LA-5 against Botrytis cinerea

LI Pei-qian, FENG Bao-zhen, LI Xin-xiu, HAO Hao-yong
Chinese Journal of Applied Ecology. 2018, 29 (12): 4172 doi: 10.13287/j.1001-9332.201812.034
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In this study, actinomycetes were isolated from rhizosphere soil of tomato by spread plate method, with the pathogen Botrytis cinerea as the target fungus. An actinomycete isolate LA-5 with strong antifungal activity was obtained by confrontation culture and Oxford cup double screening method. According to cultural characteristics, physiological and biochemical properties and 16S rDNA analysis, the strain LA-5 was primarily identified as Streptomyces chungwhensis. The second screening results showed that the fermentation filtrate of LA-5 could substantially inhibit the spore germination and mycelium growth of B. cinerea. Both conidium germination and mycelia growth could be inhibited by 100 times fermentation broth of LA-5, with the inhibiting rate being higher than 50%. Furthermore, the inhibited colony showed white mycelia, with sparse and thin aerial hypha, and the obviously decreased branches. Results from in vitro biocontrol experiment showed that control efficiency of filtrate from LA-5 fermentation liquid on B. cinerea could be up to 83.4%, indicating that the strain was a potential antagonist against tomato gray mold.

Effects of seed traits and seed production on the seed predation and dispersal behavior of rodents

LUO Yong-hong, YAN Xing-fu, ZHOU Li-biao, MIAO Ying-quan, ZHANG Jin-feng
Chinese Journal of Applied Ecology. 2018, 29 (12): 4181 doi: 10.13287/j.1001-9332.201812.033
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To deeply understand the foraging behavioral strategies of the rodents in response to seeds of different sizes and tannin contents under different seed densities and its relationship with plant regeneration, field experiments were conducted to explore the effects of artificial seeds of different sizes (large and small) and tannin (T) contents (0%T, 2%T, 8%T, and 15%T) on seed predation and dispersal behavior of rodents during simulated non-mast and mast seeding year in Larix principis-rupprechtii plantation of Liupan Mountains in Ningxia. The results showed that seeds were consumed rapidly by rodents in non-mast seeding year but relatively slow in mast seeding year. No significant difference of in situ predation rate (ISPR) was observed between non-mast and mast seeding year. The predation rates of seeds after dispersal (PRAD) by rodents in non-mast year were significantly higher than those in mast year, while the hoarding rate of seed after dispersal (HRAD) of the former was significantly lower than the latter. Both seed predation distance after dispersal (PDAD) and hoarding distance after dispersal (HDAD) by rodents in non-mast year were substantially higher than those in mast year. In non-mast year, both PDAD and HDAD of large seeds were longer than those of small seeds. Significant difference of the former was observed between large and small seeds for all tannin content seeds, but significant difference of the latter between large and small seeds was detected only for seeds of 2% and 15% tannin. In mast year, significant difference of PDADs and HDADs between large and small seeds was found in all other seeds of tannin contents except for 0% Tannin seeds. The ISPR maximized in medium tannin seeds and minimized in high tannin seeds. Maximums of PRAD were observed in high tannin seeds in non-mast year and 0% tannin seeds in mast year respectively. High tannin seeds had the highest HRAD while medium tannin seeds had the lowest HRAD in both mast and non-mast year. Our results suggested that mast seeding year could delay the seed consumption rate of rodents and increase the HRAD, but reduce the dispersal distance. Hoarding preference of the rodents on large seeds was demonstrated in both mast and non-mast years and the dispersal distance of large seeds was longer than those of small ones. It is probably that rodents prefer to predate in situ seeds of medium tannin and disperse high tannin seeds during both mast and non-mast years.

Effects of aluminum toxicity on physiological and leaf chlorophyll fluorescent characteristics of rubber tree seedlings

AN Feng, LI Chang-zhen, ZHANG Ting-ting, WANG Li-feng, WANG Ji-kun, XIE Gui-shui
Chinese Journal of Applied Ecology. 2018, 29 (12): 4191 doi: 10.13287/j.1001-9332.201812.006
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Aluminum toxicity is common in tropical acid soils. However, its effects on rubber tree growth and latex production are still unclear. Using potted sand culture seedlings of rubber tree, the effects of different aluminum ion concentrations on physiological and chlorophyll (Chl) fluorescence characteristics were investigated. The results showed that the cell membrane permeability, free proline content, and soluble sugar content were significantly increased, while the relative water content, catalase and peroxidase activities, Chl a content, Chl maximum fluorescence yield, maximum photosynthesis efficiency and potential activity of PSII, photochemical quenching coefficient, non-photochemical quenching coefficient and photosynthetic electron transport rate were significantly decreased when the saplings were subjected to AlCl3 treatments with concentration higher than 200 mmol·L-1. When the AlCl3 concentration was lower than 100 mmol·L-1, the aforementioned parameters did not show any significant variation among different treatments for the entire duration of the experiment. These results indicated that the rubber tree could tolerate some degree of aluminum toxicity. The threshold concentration of aluminum toxicity for rubber tree seedlings would be between 100 to 200 mmol·L-1. When this threshold was exceeded, aluminum toxicity would cause irreversible damage to rubber tree seedlings.

Exogenous NO mediated the detoxification pathway of tomato seedlings under different stress of Cu and Cd

WANG Yi-jun, HU Mei-mei, CUI Xiu-min, LOU Yan-hong, ZHUGE Yu-ping
Chinese Journal of Applied Ecology. 2018, 29 (12): 4199 doi: 10.13287/j.1001-9332.201812.031
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Nitric oxide (NO) is a well-known signaling molecular that plays a significant role in stress tolerance of plants to heavy metals. However, the detoxification mechanism of NO has not been well studied. Here, we examined the absorbing and transporting characteristics of copper (Cu) and cadmium (Cd) in tomato seedlings through nutrient solution culture and its response to exogenous NO under Cu and/or Cd stress. Results showed that Cu and Cd with the concentration of 50 μmol·L-1 greatly inhibited plant growth, with Cd having a higher inhibiting effect than Cu. Under single or dual stresses of Cu and Cd, their contents in both tomato roots and leaves were significantly increased. However, tomato roots showed preference to essential element Cu with a luxury uptake and strictly against Cd through cell plasma membrane in which the content of Cd was only one tenth of Cu in plants. These metal stresses, especially Cd stress, could be alleviated by application of exogenous NO. Tomato plants detoxify these passively-absorbed elements through similar mechanisms, including chelation with glutathione, phytochelatin or metallothionein, as well as vascular compartmentalization. Exogenous NO could alleviate these stresses through regulating the oxidation-reduction condition of GSH-GSSH, controlling the metabolism of GSH-PCs, as well as promoting the vascular compartmentalization of excessive Cu and Cd. In addition, NO could induce higher expression of chelators, such as MTs, GSH and PCs, in both roots and shoots, which showed additive effects to other responses and might be another important detoxification pathway mediated through NO for the responses of tomato plants to Cu and Cd stresses.

Effects of macrophyte cultivation on community structure of rotifer in small lakes

ZHANG Yi, WEI Nan, WANG Qing, LIANG Di-wen, YANG Yu-feng
Chinese Journal of Applied Ecology. 2018, 29 (12): 4208 doi: 10.13287/j.1001-9332.201812.039
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To understand the effects of macrophyte growth on water environment and rotifer community structure, monthly survey lasted for one year from October 2015 to September 2016 was conducted in Lake Minghu and Lake Nanhu at Jinan University in Guangzhou. There was no macrophyte cultivation in Lake Minghu. A kind of macrophyte Hydrilla verticillata grows from March-October in Lake Nanhu and grows vigorously in June-September. In this study, 50 species belonging to 23 gene-ra of rotifer, were recorded in the two lakes. 32 species were found in Lake Minghu and 39 species in Lake Nanhu, respectively. The dominant species in Lake Minghu were Polyarthra vulgaris, Trichocerca pusilla and Liliferotrocha subtilis. The dominant species in Lake Nanhu were Keratella cochlearis, Colurella adriatica and Lecane (Monostyla) bulla. The highest abundance of rotifers in Lake Minghu was at 3790 ind·L-1 in October 2015, and the lowest at 854 ind·L-1 in March 2016. The highest abundance of rotifers in Lake Nanhu was at 3555 ind·L-1 in November 2015, and the lowest at 977 ind·L-1 in January 2016. Results from the ANOSIM (one-way) test revealed that the community structure of rotifers was significantly different between Lake Minghu and Lake Nanhu. The largest contribution rate of the difference between the two lakes was made by Keratella cochlearis and Polyarthra vulgaris. RDA analysis showed that total phosphorus, chlorophyll a, and water temperature had significant impacts on the community structure of rotifer in Lake Minghu. During the period with luxuriant macrophyte in Lake Nanhu, the rotifer community structure was most influenced by total phosphorus, water temperature, chlorophyll a and water depth, dominated by benthic species Squatinella mutica, Colurella adriatica and Lecane bulla. During the period with sparse macrophyte, the community was mainly influenced by total nitrogen and transparency, dominanted by planktonic species Polyarthra vulgaris and Trichocerca similis. During the period with no macrophyte, communities were mainly influenced by pH and dissolved oxygen, and also dominated by planktonic ones Polyarthra vulgaris and Anuraeopsis fissa. Macrophyte could effectively absorb nutrients in water, inhibit growth of phytoplankton, improve water quality, increase spatial heterogeneity, support more species of rotifer, and maintain a stable aquatic ecosystem.

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