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Volume 33 Issue 3
25 March 2017
Assessment of and Controlling Strategies for Ecological Risks of Land Consolidation Based on Ecosystem Services
LIU Shi-liang, HOU Xiao-yun, ZHANG Yue-qiu, YIN Yi-jie, WANG Jun
2017, 33(3):  193-200.  doi:10.11934/j.issn.1673-4831.2017.03.001
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Ecological risk assessment and management of land consolidation are two objective requirements of the sustainable development of land resources under the background of ecological civilization. During the 13th Five-year Plan period, land consolidation will increase in investment and scale, which will not only bring about positive effects on regional social and economic development, but also have profound impacts on structure and functions of regional ecosystems. How to monitor and control ecological risks has become an issue causing more and more attention. On the basis of systematic elaboration of the connotation and characteristics of ecological risks of the land consolidation, analysis was done of ecological risk factors and evaluation index system relative to ecological effect of land consolidation, and thereof, a new idea was brought forth about identification, assessment and control of ecological risks based on full-process analysis of land consolidation projects, including ecosystem service functions as an important content of ecological risk assessment. Thus the limitation of the researches in the past on ecological risk has been overcome with more emphases on changes in structure and functions of an ecosystem. Scientific issues and development trend that need more attention in tackling ecological risks of land consolidation are pinpointed.

Characteristics of the Temporal and Spatial Variation of Anthropogenic Heat Flux in South China
ZHU Kuan-guang, ZHAO Wei, XIE Min, ZHU Xin-sheng, LI Ming-gao, FENG Wen
2017, 33(3):  201-206.  doi:10.11934/j.issn.1673-4831.2017.03.002
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Based on the data of regional energy consumption and population published in the "China Statistics Yearbooks" and the "China Energy Yearbooks" in 1990-2015, analyses were done for temporal and spatial distribution of anthropogenic heat flux (AHF) in South China (i. e. Hainan, Guangdong, Guangxi and Hong Kong) and its affecting factors. Results show that AHF kept going up with the time passing by in Hainan, Guangdong, and Guangxi, with the annual mean AHF rising from 0.09, 0.47 and 0.16 W·m-2 in 1995 to 0.49, 1.68 and 0.44 W·m-2 in 2014, respectively. AHF distributed unevenly in space. The year of 2010 found that the downtown areas of Zhanjiang, Haikou and those major cities in the Pearl River Delta and the Chaoshan District, were the centers of the regions relatively high in AHF, with Guangzhou and Hong Kong in particular, being 50 and 100 W·m-2, respectively, in AHF. Such a pattern of AHF distribution is thought to be closely related to the high degrees of industrial and commercial development and the high densities of population. During the period from 1995 to 2010, AHF in the above mentioned cities grew the most quickly or by as high as 0.7 W·m-2·a-1. The rapidly growing AHF will sure bring about greater impacts on climate and air quality of the regions in South China. It is, therefore, essential to pay more attention to the study on AHF and its effects.

Estimation of Greenhouse Gas Emissions in Scaled Crop-Livestock Integrated Farms in North China Plain
SHI Peng-fei, ZHENG Yuan-yuan, YANG Dong-yu, DANG Jing, WANG Gui-yan
2017, 33(3):  207-214.  doi:10.11934/j.issn.1673-4831.2017.03.003
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The North China Plain is one of the most important crop and livestock production regions, and large-scaled crop and livestock integrated farms are common and typical of the region and thought to be an effective way to solve the environment pollution. Emission of greenhouse gases from the crop and livestock system is already accepted as a main cause of climate change. The objective of this study is to quantify greenhouse gas (GHG) emission from a farm of such a nature in the North China Plain. The life-cycle-based assessment method was used to estimate GHG emission during the operation of the farm by referring to the calculation methodology and emission coefficients specified in the "IPCC 2006 National Guide for and List of GHG" . Results show that the annual total GHG emission from the farm was 32 528.02 t (CO2-equivalence, the same below), among which the farming system contributed 28.09%, and the livestock system did 71.91%. During the operation of the farm, the processes of livestock waste handling and storage, animal feed production and processing, intestinal fermentation and nitrogen production and application were the main sources of GHG emission, contributing 34.66%, 21.24%, 15.48% and 20.08% to the total, respectively. The production of 1 kg of wheat and maize grains emitted 1 059.39 and 411.92 kg, respectively; the production of 1 kg of raw milk and 1 kg of fat-protein corrected milk (FPCM) did 1.04 and 1.14 kg, respectively, which was lower than the average of the world; and production of 1 kg of live pig and beef cattle did 2.58 and 10.00 kg, respectively, similar to those from other intensive animal farms in the country. Scenario analysis shows that to reduce N (fertilizer) application rate, improve the capacity of handling and treating livestock waste, intensify N management and modify feed composition may directly or indirectly mitigate GHG emissions from such farms.

Spatio-Temporal Distribution of Heavy Metals in the Surface Water and Sediment of the Lake Taihu Basin and Assessment of Their Potential Ecological Risks
FANG Bin-bin, YU Yang, JIANG Wei-li, CHANG Wen-jie, DU Ming-yong, ZHANG Min
2017, 33(3):  215-224.  doi:10.11934/j.issn.1673-4831.2017.03.004
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A total of 98 monitoring sites were set up in the Lake Taihu Basin and water and sediment samples were collected routinely from these sites during the period from November 2012 to August 2013 for analysis of heavy metals (Cr, Cu, Zn, As, Cd, Pb and Hg) with the Inductively Coupled Plasma-Mass Spectromtry (ICP-MS) and a Direct Mercury Analyzer, to explore content distribution characteristics of the heavy metals and status quo of heavy metals pollution of the region. Results show that: the seven heavy metals (Cr, Cu, Zn, As, Cd, Pb and Hg) in the surface water did not exceed the criteria set in the National Environmental Quality Standards for Surface Water in content, being 0.88, 3.21, 10.96, 3.29, 0.019, 0.07 and 0.021 μg·L-1, on average, while the content of Cr, Cu, Zn, Cd and Pb in the sediment was 102.32, 65.24, 185.64, 0.93 and 45.88 mg·kg-1, on average, all exceeding the criteria set in the standard, especially the content of Cd, being 4.7 times as high as the criterion in the standard. However, the content of As and Hg was only 9.87 and 0.107 mg·kg-1 on average, respectively, or 65.8% and 71.3% of their respective criterion in the standard. Contents of the seven heavy metals in the surface water and sediment varied significantly in temporal and spatial distribution. The concentrations of Cr and Cu in the surface water were higher during the normal water seasons than during the high or low water seasons, and the concentrations of Zn and As the highest during the high water season, whereas the concentrations of Cd, Pb and Hg relatively unchanged throughout all the three seasons. Cr, Cu, Zn, As, Cd and Hg were the highest in concentration in the Canal water system area, the lowest in the water body of Shaoxi and moderate in the water body of Lake Taihu. In the sediments, the concentrations of Cr and Cu were higher during the normal water season than during the high or low water seasons; the concentrations of Zn, Cd and Hg were the highest during the high water seasons and the lowest during the low water season; and the concentrations of As and Hg were the highest during the low water seasons in the sediments of the Canal water system and the effluent system, the concentrations of Cr, Cu and Pb were significantly higher than the criteria in the standard, while in the sediments of the other water system, their concentrations were lower or approximate to the criteria in the standard. Zn content in the sediments was the highest in the effluent water system and the Canal water system, while Cd content was in the Yili water system and the Taihu Lake water system. In the sediments of the Taihu Lake Basin, the 7 heavy metals followed a decreasing order of Cd > Hg > Cu > As > Pb > Cr > Zn as potential ecological risk factor, among which Cd was the paramount one, reaching the heavy level in ecological hazard degree. Of the heavy metals, the ecological risk index in the Yixi River water system was rated as heavy ecological hazard, being 278.13, while the indices in the other areas as moderate ecological hazard.

Niches of the Major Plant Populations in Grasslands Typical of the Poyang Lake Wetland in Five Resources-Environmental Gradients
DUAN Hou-lang, ZHAO An, YAO Zhong
2017, 33(3):  225-233.  doi:10.11934/j.issn.1673-4831.2017.03.005
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Data of 10 dominant plant species and 5 resources-environmental factors (elevation, soil pH, electrical conductivity, water content and organic matter content) were gathered through surveys of 95 quadrates (1 m×1 m) in 19 sample plots (5 m×5 m) in the Chayegang Grassland of the Henghu Farm, typical of the Poyang Lake wetland, and analyzed for breadths and overlaps of the ecological niches of the plant populations, using the indices of Levins niche breadth and Pianka niche overlap. Results show that: (1) Carex cinerascens and Phalaris arundinacea are the dominant species in the region and have broader niche along the five resources-environmental gradients, while Cyperus michelianus, Rorippa cantoniensis, Phragmites australis and some others are accidental species and have relatively narrow niches; (2) The 10 plant species rarely overlap in niche, but exception exists with Eleocharis valleculosa, Cyperus michelianus and Rorippa cantoniensis, which overlap each other much more than the other plant species pairs; (3) Of the 10 major plant populations, niche breadth is significantly (P<0.05) or extra-significantly (P<0.01) and positively related to other important values, but extra-significantly (P<0.01) and negatively related to variation coefficient of their important values. The 10 dominant plant species vary sharply in resource-environment utilization capability and adaptability to the 5 environmental factors, and are generally low in niche overlap. Importance values of the plant species are the major factors dictating niche breadth.

Response of Small-Medium-Diametered Moso Bamboo (Phyllostachys edulis) to Mulching and Fallow Alternation in Plasticity
LI Wei-cheng, TIAN Xin-li, SHENG Hai-yan, YANG Hui-min, GAO Gui-bin
2017, 33(3):  234-241.  doi:10.11934/j.issn.1673-4831.2017.03.006
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A field experiment was carried out on adoption of a mulching and fallow alternation system in a tract of low-yielding moso bamboo groves, of small and medium in diameter, to explore effects of the practice on generation pattern of ramet, root system, spacing behavior and vertical distribution of fine roots of the plants and on behavioral mechanism of the clonal population and ecosystem of the bamboo groves. The experiment had five sample plots set for treatments, separately: control (CK), mulching in the first year (C1), mulching in the third year (C3), alternate in the first year (R1) and alternate in the second year (R2). Results show that ramet germination rate of the Moso Bamboo ranged between (20.65±4.03)%-(35.26±1.18)% relative to season. Rich soil nutrients in the soil triggered explosive ramet. In Treatment C1 and C3 the number of ramet reached (35.2±7.7) and (27.8±4.2) per square meter, respectively, breaking up the autologous rules of life developed through a long evolution process, concerning growth and multiplication, which is a type of passive adaptation. Mulching with organic materials initially elevated diameter of the bamboo at eyebrow height, but reduced it with the mulching going on. Moreover, it raised significantly the number of dormant buds on new roots (1-2 years old), but affected reversely the number of dormant buds on both new and prime roots with the mulching going on. The number of dormant buds began to turn up when fallow started. To a certain extent, fallow reduced elongation rate of the young roots, but later on it increased the rate somewhat. Moso Bamboos took advantage of the plasticity of its nutrient adsorption organ, i. e. root, in structure, such as reducing diameter of its new roots, and increasing length of its new roots and extending space between buds on the new roots, to open up a new suitable habitat. In Treatment C3, the mean biomass of fine roots declined down to 64.07% of that in Treatment C1. Mulching not only reduced the biomass of fine roots, but also had it concentrated in the surface soil layer, while fallow promoted growth of fine roots deeper and increased the biomass of fine roots as well. In Treatment CK, large volumes of fine roots were distributed in both the surface and sub-soil layers, and Treatments R1 and R2 differed from Treatment CK only in peak value, which indicates that the fine roots of bamboo adapt to different habitats by redistributing the biomass. The technique of mulching the field with organic materials in bamboo forest is an efficient approach to increase and maintain soil temperature and moisture in order to enhance shoot bud formation and early germination. However, Treatment C3 did demonstrate that mulching obviously affects the number of dormant buds, the length of new roots, the space between buds and the biomass of fine roots, while the subsequent fallow helped restore them somewhat. It is, therefore, concluded that fallow is an essential complement to mulching for bamboo groves.

Distribution of Soil Carbon and Nitrogen Stocks in Salt Marsh Wetland in Dongtan of Chongming
CHEN Huai-pu, ZHANG Tian-yu, GE Zhen-ming, ZHANG Li-quan
2017, 33(3):  242-251.  doi:10.11934/j.issn.1673-4831.2017.03.007
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Coastal salt marsh wetlands are important pools of carbon and nitrogen. Spatio-temporal distributions of the soil organic carbon (SOC) and total nitrogen (TN) stocks therein are affected by both biological and environmental factors. In this paper, spatio-temporal distribution and vertical distribution (0-50 cm) of soil organic carbon and total nitrogen stocks in the Dongtan wetlands during 2013 was studied. Results show that both the SOC and TN stocks varied seasonally, following an order of winter > autumn > summer > spring, and accumulated with the time passing by, and varied spatially, too, showing a decreasing order of Phagmites australis belt in high tidal marsh > Spartina alterniflora belt in medium-tidal marsh > Scirpus mariqueter belt in low-tidal marsh > bare mudflat. However, along the belts, regardless of vegetation, the SOC and TN stocks was higher in the northern transect than in the middle and southern transects. Vertically the stocks distributed in the soil profiles in similar patterns in all areas. Generally SOC stock peaked in the >10-15 cm soil layer in the mudflat and S. mariqueter marsh, and in the surface soil layer(0-10 cm soil layer) and the >20-30 cm soil layer in the P. australis marsh and S. alterniflora marsh. The vertical distribution of TN stock was quite similar to that of SOC stock, showing an extremely significant positive correlation (P<0.01). All the findings in this study suggest that in the study area the type of the vegetation in the salt marsh is the major factor affecting the SOC and TN stocks, while in the bare mudflat, tide and sedimentation are the major affecting factors.

As(Ⅲ) Adsorption Effects of Montmorillonite, Iron Oxides and Their Complex
DENG Tian-tian, MA Pei, LI Han-sheng
2017, 33(3):  252-259.  doi:10.11934/j.issn.1673-4831.2017.03.008
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A modified montmorillonite complex was prepared out of montmorillonite and FeCl3·6H2O, and used in comparison between montmorillonite, iron oxide and the modified complex in adsorption of As(Ⅲ). Results show that the kinetics of the three adsorbents adsorbing As(Ⅲ) in water fit the Lagergren speed equation, and all belong to the sort of Freundlich sorption isotherm. The modified complex is obviously superior to the other two in setting efficiency. Besides, it is capable of regulating pH of the arsenic solution. Competitive adsorption experiments on some common ions come to the conclusion that calcium ion has some positive effect, while magnesium and sulfate has little on removal efficiency of arsenic, and nitrate and phosphate competes vigorously with As(Ⅲ) for adsorption.

Effect of Sediment Redox on Physiological Ecology and Heavy Metal Uptake of Vallisneria natans
RUI Sheng-yang, WU Juan, CUI Na-xin, LI Zhu, KONG Ling-wei, CHENG Shui-ping
2017, 33(3):  260-264.  doi:10.11934/j.issn.1673-4831.2017.03.009
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Degradation of organic matter in sediments of water body would deplete oxygen in the sediment, resulting in an anoxic condition therein, which in turn affects growth of submerged macrophytes and their uptake of certain heavy metals. Under the condition of simulated anoxic sediment, Vallisneria natans was grown and monitored for stress of heavy metal pollutants in the sediment and contents of the elements in the plant tissues. Results show that the anoxic condition of the heavy metals polluted sediment lowered chlorophyll content, POD activity and soluble protein content in V. natans, raised soluble sugar content, promoted growth of the plant in biomass when the anoxic condition was kept at a certain level, and increased the uptake of Cr, Ni, Pb and Cu up to 2.2, 5.4, 3.0 and 1.5 times as high as in the tissues of the plant under the control condition, while the uptake of Zn in the shoot and root was suppressed and lowered to 64% and 81% of that, respectively, in the control. All the findings demonstrate that the redox condition of sediments significantly affects the physiology of V. natans and heavy metals uptake of the plant.

Release of Cu and Cd From Contaminated Soil Amended by Nanoparticle and Microparticle Hydroxyapatite in the Condition of Acid Deposition
ZHU Zhen-qiu, ZHOU Jing, XU Lei, LIU Chuang-hui, GAO Min, LIANG Jia-ni
2017, 33(3):  265-269.  doi:10.11934/j.issn.1673-4831.2017.03.010
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Release characteristics of Cu and Cd from compound contaminated soil under simulated acid rain were studied through a leaching experiment for the untreated soil and hydroxyapatite amended soil with a rate of 1%. EC, pH, Cu and Cd concentration of leaching solution and before and after leaching of soil heavy metal bioavailability were analyzed. The result show that the leaching solution pH order is MHA >NHA >CK, higher than simulated acid rain pH. MHA and NHA treatments increase the leaching solution conductivity (EC), especially for MHA with its leaching solution EC was 10.41 times as high as that of CK. Compared with CK, MHA significantly increased Cu concentration of the leaching solution, and had been maintained at a higher level, while the NHA decreased the Cu concentration of the leaching solution, but MHA and NHA both decrease Cd concentration of the leaching solution. Before leaching Cu and Cd bioavailability of MHA treated soil were reduced by 75.0% and 90.7%, respectively, while for NHA treatment the rates were 59.6% and 52.2%, respectively, indicating that MHA can be more effective stabilization of Cu, Cd than NHA. But in MHA treatment Cu and Cd were activated more under simulated acid rain leaching comparing with NHA, showing that MHA stabilized Cu and Cd can easily be reactivated under acid rain condition in south China.

Effect of Plant-Microbe Intensified Remediation of Soil Polluted With Oxytetracycline and Cadmium
CHEN Su, CHAO Lei, SHA Tong, SUN Jia-jun, PI Zhen-jun, CHEN Ning, MA Hong-yue, SHAN Yue
2017, 33(3):  270-274.  doi:10.11934/j.issn.1673-4831.2017.03.011
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A soil remediation experiment was carried out with maidenhair (Tagetes patula)as phyto-remedifier, bacteria (phyllobacterium myrsinacearum)-fungi (Rhodotorula mucilaginosa) mixture solution as bacto-remedifier, and fertilizers (ammonia sulfate, calcium biphosphate and potassium chloride), organic acids (tartaric acid, oxalic acid, and citric acid) and chelating agents ( NTA and EDTA) as eight separate intensifiers, to treat a soil polluted with cadmium (Cd) and oxytetracycline together. In terms of the effect of intersifying Tagetes patula's enrichment of Cd, the eight intensifiers displayed a decreasing order of ammonia sulfate≈potassium chloride> EDTA> tartaric acid> oxalic acid> calcium biphosphate >NTA> citric acid >control, while in terms of the effect of intensifying degradation of oxytetracycline, fertilizers were on the top, followed by organic acids and wound up by chelating agents. And among the fertilizers, ammonia sulfate was the most effective in remedying Cd and oxytetracycline polluted soils.

Screening and Identification of an Efficient Strain of Bacteria Degumming Eichhornia crassipes
YANG Qing, ZHANG Chao-qi, MA Li-xiao, ZHOU Wen-bing, ZHU Duan-wei, ZHOU Yi-yong, XIAO Nai-dong
2017, 33(3):  275-280.  doi:10.11934/j.issn.1673-4831.2017.03.012
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Pretreatment is the most expensive and critical step of converting biomass into energy, while biological pretreatment has attracted extensive attention for its environmental friendliness and low energy consumption. In order to find a bacteria efficient for use in biological pretreatment, degumming efficiency was chosen as the scale for strain screening. A strain, coded as A1, was isolated from the environmental media where Eichhornia crassipes grew through enrichment culture and primary screening with the Congo red plate staining method, and tested to be a strain quite efficient in degumming water hyacinth. Under the optimal conditions, Strain A1 could secrete pectinase, xylanase and cellulase as high as 3 925.00, 8 331.67 and 4 883.62 nmol·s-1·mL-1, respectively, in activity. When used in pretreatment, it could reduce the weight of water hyacinth by 33.37% through one round of degumming, and cumulatively by 49.26% after three rounds of degumming. The strain was identified as Bacillus amyloliquefaciens by means of 16S rRNA sequencing and phylogenetic tree analysis.

Distribution and Site Occupancy Analysis of 11 Species of Amphibians in Guangxi
WAN Ya-qiong, WU Jun, MO Yun-ming, WU Zheng-jun, LI Gui-fen, XU Hai-gen
2017, 33(3):  281-287.  doi:10.11934/j.issn.1673-4831.2017.03.013
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Based on the 2014 and 2015 amphibian monitoring data of the five regions (Dayao Mountain, Mao'er Mountain, Nonggang, Darong Mountain and Liuma) of Guangxi, site occupancy analysis was done using a site occupancy model. The data show that 21 species were recorded in the Dayao Mountain, 23 in the Mao'er Mountain, 15 in Nonggang, 26 in the Darong Mountain, and 13 in Liuma. Fejervarya multistriata, Microhyla fissipes, Microhyla pulchra, Boulengerana guentheri and Polypedates megacephalus were commonly found in all the five areas. Site occupancy models were used to analyze site occupancy probabilities of the 11 commonly seen species of amphibians for estimation of their site occupancy rates and detection rates, separately. With five habitat covariates and one detection covariate introduced in, the models were used to analyze effects of environmental factors on distribution of the site occupancy rates of the amphibians, and in turn, practicability, detectivity and investigation intensity of the models were evaluated, in an attempt to modify the models and make them more extensively applicable to investigation of amphibians all over the country, and to provide information for further policy-making for scientific protection and management.

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2017, 33(3):  0-0. 
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