Table of Content

10 August 2015, Volume 34 Issue 8

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Effect of gap size on soil organic carbon and total nitrogen in different types of natural Pinus koraiensis mixed forest.

DUAN Wen-biao1, JING Xin1, ZHOU Mei-heng1,2, CHEN Li-xin1**, GONG Jian-mei1, ZHANG Yu-shuang1, ZHAO Ying1, QIN Bi-da1

2015, 34(8):  2077-2084. 

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Small, medium and large gaps in three forest types, Tilia amurensis-Pinus koraiensis mixed forest (TP), Picea koraiensis-Abies fabri-Pinus koraiensis mixed forest (PAP), Betula costata-Pinus koraiensis mixed forest (BP), were selected as experimental plots, and its corresponding closed stand around each gap was set up as the controls in Xiaoxing’an Mountains of Northeast China. Soil organic carbon (SOC) and total nitrogen (TN) contents at the depth of 0-10 cm in the different sized forest gaps and their controls of various forest types were determined from June to September in 2012, aiming to illustrate the effects of gap size on the variations in SOC and TN contents in different types of natural P. koraiensis mixed forest. The results showed that gap size had no significant effect on the SOC content in the three kinds of natural Korean pine mixed forest, while had significant effect on TN content only in PAP. The SOC and TN contents varied greatly with time in the three kinds of natural P. koraiensis mixed forest. SOC content was in order of large gap>small gap>medium gap, while TN content was in order of large gap>medium gap>small gap in PAP and BP; SOC and TN contents were in order of medium gap>small gap>large gap in TP. SOC content was higher in the gaps than in the closed stands of the three kinds of forest, while TN content was lower in the gaps than in the closed stands in TP and BP, and was in the opposite order in PAP. SOC and TN contents in the different forest types were ranked in the order of PAP>TP>BP and TP>PAP>BP, respectively. The variations in SOC and TN contents over months mostly presented a unimodal type of curve with the peak values in July or August, but TN peaked in September in PAP. The difference in C/N between different size gaps in the three kinds of natural P. koraiensis mixed forests was not significant. Our study provides basic data for gap regeneration and sustainable management in natural P. koraiensis mixed forest in
Xiaoxing’an Mountains.

Influences of gap disturbance and warming on radial growth of Pinus koraiensis and Abies nephrolepis in Xiaoxing’an Mountain, Northeast China.

ZHU Liang-jun1, YANG Jing-wen1, ZHU Chen2, WANG Xiao-chun1**

2015, 34(8):  2085-2095. 

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Four ringwidth chronologies of Pinus koraiensis and Abies nephrolepis in and out of forest gaps in a broadleaved Korean pine forest in Xiaoxing’an Mountain, Northeast China were developed to explore the influence of gap disturbance (microenvironmental difference) and global warming after 1980 on tree radial growth. Results showed that the annual mean ring width of P. koraiensis out of forest gaps slightly decreased after warming, while it increased in forest gaps. The relationship between the radial growth of P. koraiensis out of forest gaps and temperature became weakened, but it became strengthened for the trees in forest gaps. The coefficients of correlation between Palmer drought severity index (PDSI) and P. koraiensis chronologies in and out of forest gaps both changed from negative to positive after warming. However, the radial growth of A. nephrolepis decreased due to forest gap disturbance. Annual mean ring width of A. nephrolepis in and out of forest gaps both decreased about 50% since climate warming after 1980. Temperature was more negatively correlated with the radial growth of A. nephrolepis out of forest gaps than with that in forest gaps. The negative effect of temperature from May to October on radial growth of A. nephrolepis out of forest gaps was obvious after 1980. The negative effect of precipitation from January to May on A. nephrolepis out of forest gaps increased, while such effect changed from negative to positive for A. nephrolepis in forest gaps. The correlation coefficients between PDSI and A. nephrolepis chronologies out of forest gaps changed from negative before warming to positive after warming, but negative correlations became more significant for A. nephrolepis in forest gaps. Our results indicate that forest gap disturbance decreases the radial growth of shaded tree species, while it has little effect on sunny tree species or slightly increases the radial growth. Tree radial growth in forest gaps is more vulnerable to be affect by external environmental change than that out of forest gaps. Gap disturbance improves the adaptability of the wet and shadetolerant species to warming by making it adapt to the warm and arid environment (forest gap environment) in advance. In addition, warming causes larger difference of growthclimate relationship between trees growing in and out of forest gaps.

Radial variation of xylem sap flow density in trunks of Eucalyptus urophylla×Eucalyptus grandis.

ZHOU Cui-ming1, HUANG Yu-qing1**, GU Da-xing1, REN Shi-qi2, ZHANG De-nan1, ZENG Dan-juan1

2015, 34(8):  2103-2108. 

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Largescale plantations of Eucalyptus urophylla × Eucalyptus grandis have been recently developed in southern China, especially in Guangxi Province. For sustainable forest and water resource management of these plantations, attention is increasingly paid to their water use efficiency. Sap flow measurement provides a powerful tool for quantifying plant water use, and it is widely employed to estimate the ecological and hydrological outcomes of plant growth. However, a potential error might occur if one applies the sap flow measurements of the outermost layer of these trees to the entire trunk or an entire plantation without considering the radial distribution of xylem sap flow density. Hence, we determined the radial distribution of xylem sap flow density in trunks of 4-year-old E. urophylla × E. grandis using the Granier thermal dissipation probe (TDP) method at the Qipo Forest Farm, Guangxi Province. We found that despite similar diurnal variation of sap flow at different depths of the trunk, sap flow at the 0-20 mm depth constituted bulk of the flow, which changed with seasons, while that of the 20-40 mm depth remain relatively stable. The curve regression analysis showed a significant exponential correlation in daily mean sap flow density (R²>0.90, P=0.00) between the 0-20 and 20-40 mm depths. Radial distribution pattern of sap flow of, E. urophylla × E. grandis showed a declining pattern with steep slope. The mean monthly sap flow density showed significant changes in the daytime, but it was relatively stable at night. Our findings will be helpful in accurately assessing the water use efficiency of this widely planted Eucalyptus hybrid by more precise calculation of its seasonal sap flow density, having significant implications for land management.

Stoichiometric characteristics of carbon, nitrogen and phosphorus of different tree species in Eucalyptus grandis mixed plantation.

CHEN Ya-mei, LIU Yang**, ZHANG Jian, YANG Wan-qin, JI Tuo-wei

2015, 34(8):  2096-2102. 

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We explored the C, N, P stoichiometry of fresh leaf, leaf litter and soil in Eucalyptus grandis mixed plantation of Toona ciliate, Alnus formosana, Sassafras tzumu and E. grandis. The results showed that the N∶P ratios of fresh leaf, leaf litter and soil ranged from 6.7 to 9.7, 8.6 to 9.7, 1.6 to 4.0, respectively. For the same components above, the C∶N ratios were 29.6 to 62.8, 78.4 to 101.8, 15.3 to 19.5, and the C∶P ratios ranged from 279.9 to 459.3, 639.0 to 795.9, 24.9 to 77.6, respectively. Among the four tree species, S. tzumu had the highest C storage capacity and N, P utilization efficiency. The leaf litter C∶N and C∶P of the three associated tree species were lower than that of E. grandis, suggesting that the leaf litter of the associated tree species was more easily decomposed and the associated trees may accelerate N, P cycling rates in the mixed forest. According to the fresh leaf N∶P <10, we found that E. grandis mixed plantation was considerably limited by N element, and E. grandis was limited more seriously. There were significant differences of soil N, P contents and C∶N∶P among different tree species, indicating that N, P cycling of Eucalyptus grandis plantation could be changed by the introduction of associated tree species. Moreover, the benefits of associated tree species in mixed plantation ecosystem will increase with forest age.


 

Interspecific relationships of dominant species and plant functional groups of wetland herb communities in Zhuozhang River watershed, Shanxi.

WANG Ye1, JIN Shan2, QIN Xiao-juan3, QIN Hao1, ZHANG Feng1,3**

2015, 34(8):  2109-2114. 

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Based on the datasets of 149 plots from the wetland herb communities in Zhuozhang River watershed, Shanxi, the relationships of 27 dominant species were analyzed by Spearman rank correlation coefficient test. The results showed among 351 pairspecies, the pairspecies of negative association (242 pairspecies) were dominant, and the ratio of positive to negative association was 3:7. The proportion of speciespairs having a significant or highly significant correlation was 16.8%. According to the association of dominant species and the adaptability of species to habitats (mainly moisture conditions), the dominant species were divided into four plant functional groups (PFGs): mesophyte, mesohydrophyte, hygrophyte and hydrophilous. The PFGs along the moisture gradient were distributed in the top of flooding plain, the lower of flooding plain, the seasonal watering area of flooding plain, and the river and marsh of Zhuozhang River, respectively.

 

Reallocation and chemical characteristics of precipitation in a Maolan karst forest.

LU Xiao-qiang1, YANG Wan-xia2, DING Fang-jun3, TODA Hiroto4

2015, 34(8):  2115-2122. 

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Precipitation, throughfall, and stemflow were collected during the period of September, 2007 to August, 2009 from a subtropical natural evergreen and deciduous broadleaf mixed forest in Maolan, a karst area in Southwest China. The concentrations of major ions (Ca²⁺, Mg²⁺, K⁺, Na⁺, NH₄⁺, SO₄^2-, NO₃^-, Cl^-) were determined for collected samples in order to quantify the annual amounts of major nutrient elements and to examine changes in chemical composition of precipitation after passing through the canopy. The results showed that: (1) the concentrations of the major nutrient ions in precipitation, throughfall and stemflow were lower during the summer (from July to September), but higher in the winter (from December to the following February); (2) compared with precipitation, the concentrations of Ca²⁺, Mg²⁺, K⁺, Cl^-, NO₃^-, and SO₄^2- in throughfall and stemflow increased obviously, while there was a decrease in NH₄⁺ concentration and no significant variation in Na⁺ concentration; (3) the annual inputs of nutrient ions via precipitation were in order of Ca²⁺>SO₄^2->NH₄⁺-N>Cl^->K⁺ >Na^+>Mg²⁺>NO₃^--N, and the annual inputs of nutrient elements via throughfall plus stemflow were in order of Ca²⁺>SO₄^2-S>NH₄⁺-N>Cl^->K⁺>Na⁺>Mg²⁺> NO₃^--N. Compared with nonkarst areas, low ion concentrations in local precipitation demonstrated less anthropogenic influences on the studied forests, while the concentrations of K⁺, Ca²⁺ and Mg²⁺ in throughfall and stemflow increased greatly. Our study showed that K⁺, Ca²⁺ and Mg²⁺ mainly derived from carbonate weathering were active in the hydrologic cycling of nutrients in karst forests.

Carbon, nitrogen and phosphorus stoichiometry of photosynthetic organs across Ebinur Lake Wetland Natural Reserve of Xinjiang, Northwest China.

ABLIZ Abdurahman1,2, Lv Guang-hui1,2**, ZHANG Xue-ni1,2, GONG Yan-ming1,2,3

2015, 34(8):  2123-2130. 

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Ecological stoichiometry theory states that the elements and their ratios in organisms not only determine the key features of the organisms, but also determine the resource amounts and types that organisms demand. In this paper, photosynthetic organs of 20 plant species were selected in Ebinur Lake Wetland Nature Reserve, and their characteristics of carbon, nitrogen and phosphorus stoichiometry were analyzed. The results showed that C, N, and P concentrations in photosynthetic organs ranged from 209.48 to 728.18 mg·g^-1 (with an average of 429.60±99.05) mg·g^-1, 11.23 to 42.57 mg·g^-1 (with an average of 20.52±5.78) mg·g^-1, and 0.39 to 3.50 mg·g^-1 (with an average of 0.93±0.42) mg·g^-1, respectively. The C∶N, C∶P and N∶P ratios were 22.74±8.88, 512.93±186.53, 25.64±16.74, respectively. From the point of view of plant life forms, shrubs and herbaceous plants had a lower storage capacity for C than trees, while there was no significant difference in P concentration among the three life forms. In terms of plant functional types, C, N, P, C∶N, C∶P, N∶P of assimilating branches were not significantly different from those of leaves. Comparing the results of this research with the global and Chinese scales found that plants in Ebinur Nature Reserve had lower P concentration, higher N∶P and C∶P, indicating shortages of N and P, especially P in plants studied.

Leaf traits of Quercus wutaishanica  and their relationship with topographic factors in Mount Dongling.

CHEN Chen1, LIU Dan-hui1, WU Jian-jun1, KANG Mu-yi2,3**, ZHANG Jin-tun1, LIU Quan-ru1, LIANG Yu1

2015, 34(8):  2131-2139. 

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Topographic features often play a role in redistributing the ecological factors such as light, temperature, rainfall and so on, thus altering the tree growth. Leaf samples of Quercus wutaishanica were collected and topographical factors were investigated in the southern slope of Mount Dongling, to study the tree species’ specific leaf area (SLA), leaf dry matter content (LDMC) and some other traits in leaf structure, aiming to examine the adaptive responses of those traits to variable topographic factors. Significant correlations were found among SLA, LDMC, leaf density (LD). The leaf traits, such as leaf size (LS), leaf fresh weight (LFW) and leaf dry weight (LDW), decreased at first and then increased with increasing the altitude, presenting a quadratic trend, with the minimums occurring at the elevation of 1400-1600 m. The relationship between the leaf traits (SLA, LDMC) and the altitude in the valley was different from that in the ridge, which could be explained by the different local water regimes resulted from the topographic change of valleytoridge locations. LS, LFW and LDW differentiated significantly from sunny to shady slope exposures. Altitude was the primary factor influencing SLA, LDMC, whereas slope aspect dominated the shaping of LS, LDW and LFW.

 

Effects of intercropping soybean varieties with different kin relationships on the growth and nitrogen utilization efficiency.

XIAO Tao-yan, LIN Wei-peng, CAI Kun-zheng**

2015, 34(8):  2140-2148. 

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In order to investigate the effects of soybean varieties with different kin relationships on the growth and nitrogen utilization efficiency, three soybean (Glycine max) varieties with different kin relationships were selected for this intercropping experiment. Soybean variety Huaxia 3 (A) was the target variety which was intercropped separately with Huaxia 3 (A), Guizao 1 (B) which was one parent variety of Huaxia 3, or Zhonghuang 24 (C) with no close phylogenetic relationship with Huaxia 3. The experiment was conducted under low nitrogen level (LN, 0.6 mg·L^-1) and high nitrogen level (HN, 60 mg·L^-1) by using sand culture method. There were 4 soybean plants in each pot with two plants of A and two plants of variety A, B, or C, forming treatments LN-AA, LN-AB, LN-AC, HN-AA, HN-AB, HN-AC with four replicates for each treatment. The result showed that the plant biomass, total root length, root volume of variety A intercropped with variety C were higher than with variety B. The total root length and root volume of A increased by 50% and 57% under LN-AC than under LN-AB, and by 46% and 50% under HN-AC than under HN-AB, respectively. The nitrate reductase activity (NRA) of A was higher when intercropping with C than with B. NRA was 56% higher in LN-AC than in LN-AB and was 49% higher in HN-AC than in HN-AB. There were no significant differences among treatments in total nitrogen content of leaf and stem (NCLS) at the fullbloom stage. However, NCLS of A variety in HN-AB was significantly higher than in HN-AC at the podfilling stage. The same trend of kinship influence was observed under LN treatment at the podfilling stage. In general, kin recognition exists in soybean and the recognition ability is affected by its growth stage.

Effects of brassinolide on the growth and ascorbate-glutathione cycle of cucumber seedling roots under suboptimal temperature, light and salt environment.

WU Xiu, LU Xiao-min**

2015, 34(8):  2149-2154. 

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The effects of 24epibrassinolide (EBR) on the growth and ascorbateglutathione (AsA-GSH) cycle in cucumber (‘Jinchun 2’) seedling roots under suboptimal temperature, light and salt environment were studied. The results showed that under the suboptimal environment, the superoxide anion (O₂^-_·) production rate, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents were increased, and lipid peroxidation was aggravated in cucumber seedling roots, which significantly inhibited the growth of seedling roots. EBR improved the activities of antioxidant enzymes such as ascorbate peroxidase (APX), glutathione reductase (GR) and dehydroascorbate reductase (DHAR), increased the contents of ascorbic acid (AsA) and glutathione (GSH) and the ratios of AsA/DHA and GSH/GSSG in roots of cucumber seedlings under the suboptimal environment. Moreover, EBR effectively promoted the metabolism of AsAGSH cycle in cucumber seedling roots, and maintained a strong antioxidant ability, which significantly reduced the H₂O₂ and MDA contents and the superoxide anion production rate, reduced the membrane lipid peroxide level, consequently promoting the root growth of cucumber seedlings under the suboptimal temperature, light and salt environment.

Water absorbance features of seed mucilage of an invasive plant, Plantago virginica, and its germination response to drought stress.

LUO Hui1, YAN Xiao-hong2, ZHOU Bing2**, WANG Ning2, YANG Jia-qin

2015, 34(8):  2155-2160. 

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Plantago virginica is one of the widespread invasive weeds in southern China. The seed germination in different postharvest months, water absorption of seed mucilage and the germination of the seeds with or without mucilage under different osmosis were studied in laboratory to assess its seed dormancy and germination properties, and the effects of the mucilage in seed germination under drought environment. The seeds of P. virginica had a dormancy period about one month and kept high germination rates 2 to 9 months after mature (48.75%-88.75%). The water absorption ability of the seeds with mucilage was obviously higher than that of the seeds without mucilage, and the water absorbed by the mucilage was 59 times or so as its dry mass. Compared with the control, the germination rates of the seeds with mucilage and without mucilage decreased by 18.58% and 62.71% respectively under the osmosis stress from -1.21 to 0 MPa. Our experimental findings suggested that the characteristics of P. virginica such as short dormancy period and high germination rate of the seeds, and the obviously strong water absorption ability of seed mucilage, might contribute to its adaptation to the drought environment and indirectly enhance its invasive capability.

Effects of waterlogging during seedling stage on the growth and yield of summer maize in HuangHuai Region.

YU Wei-dong1,2, FENG Li-ping2, HU Cheng-da1, PENG Ji-yong1

2015, 34(8):  2161-2166. 

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In this study, a pot experiment was conducted to investigate the effect of waterlogging during the seedling stage on the growth and grain yield of summer maize. Different treatments of surface waterlogging (for 3, 5 or 7 d) and subsurface waterlogging (for 5, 10 or 15 d) were included during the 4-leaf stage of summer maize cultivar Xundan No. 20. The results showed that surface waterlogging at the seedling stage for 3 d or more and subsurface waterlogging for 15 d decreased the grain yield significantly. Compared with the CK, surface waterlogging for 3-7 d decreased maize yield by 58.8%-69.8% (P<0.05), while subsurface waterlogging for 15 d decreased maize yield by 47.8% (P<0.05). Yield reduction resulted from surface waterlogging for 3-5 d or subsurface waterlogging for 15 d was mainly due to the decline in grain number per spike, while surface waterlogging for 7 d would lead to the reduction in yield by decreasing the grain number per spike and the 1000seed weight. Regression analysis of the yield loss rates and the surface waterlogging durations indicated that effective measures should be taken to control waterlogging within 1 d at the seedling stage. The effect of waterlogging on the aboveground dry matter weight of maize varied with the type and duration of waterlogging at different developmental stages. The aboveground dry matter weight after the jointing stage was significantly reduced due to surface waterlogging (P<0.05), while subsurface waterlogging did not affect significantly the aboveground dry matter weight at the maturity stage (P>0.05). Surface waterlogging for 3-7 d also affected the distribution of aboveground dry matter weight, reducing the proportion of dry matter in corncob and the harvest index by 48.7%-64.1% (P<0.05). The results indicated that the yield loss rate increased with the prolongation of waterlogging duration and the yield loss rate due to surface waterlogging was greater than that due to subsurface waterlogging.

Floral composition and distribution characteristics of wooddecaying fungi in Dongling Mountain, Beijing.

WANG Xiao-yan WEI Yu-lian**

2015, 34(8):  2167-2172. 

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Fungi growing on the woods were investigated in the Dongling Mountain Nature Reserve  to understand the community composition and substrate preference of wooddecaying fungi. A total of 1007 wooddecaying fungi individuals, representing 128 species, belonging to 24 families, 11 orders were recorded on 15 tree genera. Among them, Polyporaceae, Hymenochaetaceae and Meruliaceae were dominant families, which comprised 27.34%, 17.96% and 12.5% of total species number, respectively. There were 14 dominant species, which made up 48.76% of all occurrences. And most of these dominant species were whiterot fungi. Rarefaction curves on different substrates indicated that at decay stages of 2 and 3, most individuals and species were found on host species of Quercus and Populus, especially on substrates with diameters between 0-5 cm and larger than 10 cm, as well as substrates having barks. Besides, substrates having lower numbers of individuals might have higher wooddecaying fungi diversity. Wooddecaying fungi distributed differently on different substrates. Families at different decay stages revealed that succession species were most abundant in number and diversity, while pioneer and ultimate species were less abundant in this area. The low percentage of brownrot fungi was correlated with the presence of few coniferous trees. It is suggested that substrate protection can promote wooddecaying fungi diversity.

Effects of plant species richness on nitrate removal and net greenhouse effect in simulated constructed wetlands.

LIU Yang1, LI Dan1, SUN Hong-ying1,2, YANG Guo-fu1, CHEN Zheng-xin1,3, FAN Xing1, GE Ying1, CHANG Jie1**

2015, 34(8):  2173-2180. 

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Hydroponic microcosms of constructed wetlands were used to study the effects of plant species richness on nitrogen removal and some other ecosystem functions. Multiple functions were integrated to assess the net greenhouse effect in response to plant diversity. Microcosms with mono and mixed culture of four plant species (Oenanthe javanica, Rumex japonicus, Phalaris arundinacea, Reineckia carnea) were established and supplied regularly with simulated wastewater in which nitrate (NO₃^--N) was the sole nitrogen form. Results showed that the effluent inorganic nitrogen concentration was significantly lower in the mixed microcosms than in the monocultures, indicating that high plant species richness enhanced the nitrogen removal efficiency. The aboveground and total biomass in the mixed microcosms were higher than those in the monocultures. Denitrification was the major contributor to nitrogen removal in the monocultures, while plant nitrogen uptake was the major contributor in the mixed microcosms. Microcosms with mixed planting of four species had higher CH₄ and N₂O emissions. However, high species richness could enhance the reduction in CO₂ emission through enhancing plant biomass, which could be used as biofuel to replace the fossil fuels. After synthesizing CO₂, CH₄ and N₂O emissions, we found that high plant species richness reduced the net global warming potential (GWP) of the systems.

Phytoremediation of heavy metal contaminated soils by intercropping with Sedum plumbizincicola and Triticum aestivum and rotation with Solanum melongena.

JU Shu-yun1,2, WANG Jie2,3, SEHN Li-bo2,4, LI Zhu2, CHEN Ya-hua1**, WU Long-hua2, LUO Yong-ming2,5

2015, 34(8):  2181-2186. 

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A field plot experiment was conducted to study the effect of Sedum plumbizincicola on metal uptake by an intercropping crop of Triticum aestivum and a following crop of Solanum melongena in the subsequent growing season from heavy mental polluted soil, and to explore potential cropping systems for simultaneous remediation of contaminated soils and production of agricultural crops. The results showed that in the intercropping treatment, there was no difference in biomass of S. melongena or S. plumbizincicola. Intercropping with S. plumbizincicola significantly decreased Cd concentrations in T. aestivum by 52.4% compared to the monoculture treatment, and metal concentrations in the following crop of S. melongena also decreased markedly. Compared to the control, soil total Cd concentration in the intercropping treatment declined by 24.3%, showing highly efficient Cd removal. These results suggest that a cropping system consisting of intercropping S. plumbizincicola and T. aestivum and then rotating with S. melongena might realize the combined benefits of phytoremediation of metal polluted soil and the simultaneous safe production of food.

Distribution, sources and photodegradation characteristics of chromophoric dissolved organic matter (CDOM) in seagrass bed ecosystem of Xincun Bay, Hainan Island.

WU Yun-chao1,2, JIANG Zhi-jian1, LIU Song-lin1,2, LIAN Zhong-lian1,2,3, ZHANG Jing-ping1, HUANG Xiao-ping1**

2015, 34(8):  2187-2194. 

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Chromophoric dissolved organic matter (CDOM) is an important dissolved organic carbon reservoir in marine systems. Photodegradation of CDOM can accelerate recycling of nutrients and refractory organic matters. To examine the spatial distribution and sources of CDOM in seagrass bed in Xincun Bay, Hainan Island, the absorption coefficient \[a(355)\] and exponential slope value (S) were investigated in this region. The processes of the photo degradation of CDOM were also studied in the laboratory experiment. The results showed that the value of a(355) was highest in seagrass bed in the southern bay, followed by the small river mouth and cagefarming area, and then the center of the bay. The fluorescence intensities at 280 nm excitation \[Fn(280)\] and 350 nm excitation \[Fn(355)\] in proteinlike and humiclike substances were higher in the seagrass bed and river mouth than in the cagefarming area. These results indicated that the molecular weight of CDOM in the seagrass bed and the river mouth area were higher than that of CDOM released by phytoplankton degradation in the cagefarming area. In laboratory, after exposure to UV-B for five days, the proteinlike substances of CDOM from the seagrass bed, river mouth, and cagefarming area decreased by 44.67%, 31.75% and 37.09%, respectively, indicating that proteinlike substances in the seagrass bed absorbed UV-B more efficiently. The humiclike substances decreased by 43.64%, 36.32%, and 50.18%, respectively, which suggested the smaller molecular weight of CDOM from the cagefarming area could be degraded more easily under UV-B. Therefore, our study revealed that seagrass release, riverine inputs, and degradation from phytoplankton in cagefarming areas were the main sources of CDOM in Xincun Bay.

Effect of tourist roads on mammal activity in Shennongjia National Nature Reserve based on the trap technique of infrared cameras.

LI Jia1, CONG Jing1,2, LIU Xiao1, ZHOU Yun-yun1,3, WANG Xiu-lei1, LI Guang-liang, LI Di-Qiang1**

2015, 34(8):  2195-2200. 

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From August to September in 2010 and March to September in 2011, 36 infrared cameras were installed for monitoring the effect of tourist roads on mammal activities in Shennongjia National Nature Reserve of Hubei Province. In this study, 432 independent photos were collected and 20 mammal species were identified. The identified species belonged to 12 families and 5 orders. At distances of 0-300 and 300-600 m from the tourist roads, the frequencies of mammal activity captured by infrared cameras changed significantly, increasing from 17.25% to 26.89%, showing that the mammals had certain avoidance to the tourist roads. The daily activity and distribution zones of four ungulate species showed different responses to the tourist roads. The diurnal activities of the tufted deer (Elaphodus cephalophus) and the goral (Naemorhedus goral) changed significantly with their proximity to the tourist roads; however, the tourist roads had no effect on sika deer (Cervus nippon) or wild boar (Sus scrofa). We suggest that additional comprehensive surveys and monitoring are necessary to better understand the effect of tourist roads on wildlife.

 

Diversity and population dynamics of pest insects of Camellia oleifera captured by ultra violet light in Quzhou.

ZHANG Qin1, SHU Jin-ping1**, HUA Zheng-yuan2, YE Bi-huan1, WU Xiao-shuang1, LIU Da-fu3, JIN You-ming2, GENG Xian-sheng1, WANG Hao-jie1

2015, 34(8):  2201-2209. 

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Camellia oleifera is one of the most important economic trees and has been planted widely in subtropical areas in China. But the pest insects feeding on C. oleifera trees have seldom been concerned. The pest insects of C. oleifera and their natural enemies captured by ultra violet light in Quzhou were surveyed in the present paper, and diversity and population dynamics of the insects collected were analyzed. The results showed that 103 pest insects belonging to 6 orders, 33 families, 81 genus were found. 41521 individuals were trapped during 2012-2013, and the leaf defoliators were predominant. The seasonal dynamics of pest insect populations were influenced by the climate conditions, the growth stages of C. oleifera trees, and fruit picking. The peak period of the pest activities was from May to September, and April and October were just two transitional periods when the pests and natural enemies switched from overwintering to activity and from activity to overwintering, respectively. Natural enemies were also attracted by ultra violet light trap, and 983 individuals in 21 species were trapped in the two years. These results may provide a theoretical basis for the integrated pest management of C. oleifera.

Earthworm and soil fertility under water and fertilizer managements in a greenhouse vegetable field.

TANG Zheng1, LI Ji-guang2, LI Hui3**, YU Ning4, LI Zhong-fang1, CHEN Xiao-xiang1, CHEN Chun-lan1

2015, 34(8):  2210-2214. 

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A field experiment was conducted to investigate soil earthworm density and soil basic fertility changes and their relationship under different water (irrigation) and fertilizer (manure fertilization) managements in greenhouse organic vegetable system to provide scientific basis for reasonable irrigation and fertilization on greenhouse organic vegetable. Soil moisture, porosity, the contents of soil organic carbon, total nitrogen, available phosphorus and available potassium were significantly increased by 4%-27%, 6%-9%, 19%-27%, 19%-26%, 141%-230% and 74%-91% respectively with the increasing organic manure fertilization. Under the same irrigation, earthworm density was significantly increased by 43%-110% in the manure treatments compared with no manure treatment. There were extremely significant positive correlations between earthworm density and soil productivity, soil porosity, the contents of soil organic carbon, total nitrogen and available phosphorus. Our data indicate that soil earthworm can be a bioindicator to assess soil fertility in greenhouse vegetable fields, and can play important ecological functions. Considering soil fertility and productivity, decrementirrigation plus conventionalmanure application is the best management for sustainable organic vegetable production.

A comparative study on community structure of planktonic ciliates in different mariculture areas of Nan’ao Island in Shantou City.

WANG Shan, SHEN Zhuo, WANG Qing, YANG Yu-feng**

2015, 34(8):  2215-2221. 

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To compare the impacts of mariculture modes on ciliate community structure and aquatic environment, an investigation was carried out to analyze the ciliate and the main indexes of water quality in a natural water (control) and the areas with different modes of mariculture, i.e. finfish, shellfish and seaweed (Gracilaria), in the Nan’ao coastal waters of Shantou City in South China. Surface water and sediment samples were collected from each site once every 3-4 days from April to June, 2014. Deposition flux of cysts was studied with sediment traps. A total of 17 species of ciliates were recorded at the four sites and the range of ciliate abundance was 75-150 ind·L^-1. The community structure of planktonic ciliates in seaweed cultivation area was rich and diverse compared to the fish, shellfish and control areas based on the ciliate abundance and species diversity. The highest densities of ciliate cysts were found in the sediment of the fishfarming area, with an average of 1.9×10⁴ cysts·d^-1·m^-2, compared to the other areas. The results indicated that there existed a great difference in the community structure of the ciliates in the waters and the cysts in the sediments among different mariculture sites, and the ciliate community structure was more stable in the seaweed cultivation area compared to the other mariculture areas.

Effects of lowtemperature stress on serum biochemical parameters and metabolic enzyme activity in juvenile Epinephelus moara.

SHI Zhao-hong1,2**, ZHANG Yan-liang1,2, GAO Quan-xin1, PENG Shi-ming1, ZHANG Chen-jie1

2015, 34(8):  2222-2228. 

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An experiment was conducted to investigate serum’s biochemical indexes and activities of metabolic enzymes in juvenile Epinephelus moara in three temperature treatments (9, 13, 17 ℃; the latter as control). At the beginning of the trial, the water temperature rapidly dropped to 13 ℃ or 9 ℃ and maintained for 7 days. The results indicated that the contents of total protein (TP) and glucose (GLU) changed with the decrease of temperature, but there was no significant difference (P>0.05). At the end of the trial, there was a significant difference in the content of either triglyceride (TG) or creatinine (CREA) (P<0.05) compared with the control. The activities of the alkaline phosphatase (AKP), glutamic oxalacetic transaminase (GOT), glutamicpyruvic transaminase (GPT) and lactic dehydrogenase (LDH) increased with the increase of stress strength and stress time (P<0.05). At the end of this trial, there was a significant difference in slactate dehydrogenase activity between treatments (P<0.05). Results suggest that the stress of low temperature had no significant effect on the serum biochemical indexes in a short period. Juvenile fish can increase the activities of serum metabolic enzymes in response to the low temperature stress to improve the antistress ability. However, starvation at low temperature can lead to decreases in immunity and antioxidation capacity, so it is needed to reduce the stress strength and time of low temperature in the production process.

Classification and distribution characteristics of benthic macroinvertebrate functional groups in the saline algae zone of Chongming Dongtan.

LIN Liang-yu, TONG Chun-fu**, LI Xiu-zhen

2015, 34(8):  2229-2237. 

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Based on the surveys on benthic macroinvertebrates in the saline algae zone of Chongming Dongtan, three different types of functional group were classified according to feeding habits, life forms and traditional taxonomic characteristics. Then the compositions and spatialtemporal distribution characteristics of the functional groups were analyzed. Total 19 species were recorded during the surveys. The dominant species (IRI>20) were all from Bivalvia. The results proved that the compositions of the functional groups had obvious spatial and temporal variation characteristics. For a specific functional group and the corresponding total functional groups, the variations of spatial distribution appeared to be more significant than those of temporal distribution. The spatialtemporal distribution characteristics of the total functional groups varied with the classification types. The density and the number of species of the total lifeform functional groups showed the most significant spatialtemporal variations, while the total feedinghabit functional groups appeared to have the least. To the parameters of a specific functional group, the epifauna of the lifeform functional group proved to have the most significant spatialtemporal variation characteristics. It seems that the different functional group classifications focus on the different aspects of the benthic macroinvertebrate communities; further studies may be needed to combine them together to reflect the integral information of the system.

Evolution characteristics of biological soil crusts (BSCs) during alpine meadow degradation.

LI Yi-kang1,2, Ouyang Jing-zheng1,2, LIN Li1, ZHANG Fa-wei1, DU Yan-gong1, CAO Guang-min1, HAN Fa1**

2015, 34(8):  2238-2244. 

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Biological soil crusts (BSCs) are an important component of ecosystems, especially in arid and semiarid ecosystems, but we know little about their distribution and function on the Tibetan Plateau. In this study, we investigated the effects of alpine meadow degradation and artificial grassland construction on the distribution and growth of BSCs. Results showed that community coverage decreased with the degradation of alpine meadow. The occurrence frequency of moss was the highest in Graminaceous+Kobresia community and 6-year-old artificial grassland, and then decreased along alpine meadow degradation succession, being the lowest in black soil beach (43.6%). Black patches, white patches and lichen formed in K. humilis community, and were most abundant at Mattic epipedon crack stage of K. pygmaea meadow or Mattic epipedon erosion stage as indicated by the highest occurrence frequency, but were not observed in Graminaceous+Kobresia community, 6-year-old artificial grassland and black soil beach. The correlation analysis showed that the occurrence frequency of moss was significantly positively correlated with vegetation coverage, but negatively correlated with the occurrence frequencies of both black patches and white patches. A significant positive correlation was observed between the occurrence frequency of white patches and lichen (P<0.05). These findings demonstrate that BSCs distribute widely in alpine meadows, and vary greatly in distribution and species composition, indicating strong heterogeneity in distribution pattern due to the changes in vegetation growth and soil surface stability with meadow degradation.

Temporal and spatial changes of soil organic carbon density in Ningxia Irrigation Zone from 1980 to 2009.

DONG Lin-lin, YU Dong-sheng**, ZHANG Hai-dong, SHI Xue-zheng

2015, 34(8):  2245-2254. 

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In the Ningxia Irrigation Zone, 39 samples of soil profiles (0-100 cm) and 241 samples of surface layers (0-20 cm) were collected in 2009, and soil data attributing to 102 samples of profiles and 147 samples of surface layers were collected, which were obtained from the Second National Soil Survey of China in 1980. Then, soil organic carbon (SOC) densities in the surface layer and profile depth were calculated for the analysis of SOC stock change during the past 30 years. The results showed that SOC density of surface layer had increased significantly (P<0.01) from 16.55 Mg C·hm^-2 in 1980 to 21.44 Mg C·hm^-2 in 2009, with an annual increase of 0.98%. The SOC density in profile increased (P>0.05) from 55.70 Mg C·hm^-2 to 58.49 Mg C·hm^-2 with an annual increase of 0.17% during the past 30 years. Soil type was a major factor driving the change of SOC stock in the Ningxia Irrigation Zone. A strong relationship was found between SOC density and irrigation duration, indicating that irrigation had a prominent effect on SOC density change, the longer duration of irrigation, the higher density of SOC in the surface layer and profile. Fertilizer input, crop type and yield also affected the change of SOC density in the irrigated cropland. Non-significant relationship was found between SOC density and climate index such as air temperature and precipitation. Irrigation with Yellow River water plays a positive role in increasing SOC stock and decreasing greenhouse gas emission in Ningxia Irrigation Zone.

Variation of soil temperature in root layer under roof greening coiled material.

LIU Yang1, SUN Hai-long2**, LI Shao-cai1,3， FENG Su1

2015, 34(8):  2255-2259. 

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According to the observing data of soil temperature in root layer under three thickness of roof greening coiled materials, soil temperature under natural conditions, and air temperature, we studied the variation characteristics of soil temperature in root layer under different roof greening coiled materials by the methods of comparative analysis and linear regression. The results showed that the annual variation of soil temperature in root layer was in accord with that of air temperature. The roof coiled material had the function of insulation, and the insulation effect on soil temperature of root layer was enhanced with the increase of film thickness. The diurnal change amplitude of temperature decreased with the increase of film thickness, which could be fitted as an exponential function. Moreover, there was an extremely significant linear relationship between air temperature and soil temperature in root layer under roof greening coiled materials.

 

Effects of combined pollution of decabromodiphenyl ether and Zn²⁺ on soil enzyme and respiration.

FU Ling-fang, XIE Den-ke, FU An, CHEN Jian-zhun, LI Yin-yan, MO Ce-hui, QIN Hua-ming**

2015, 34(8):  2260-2266. 

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An indoor simulation method was conducted to study the effects of decabromodiphenyl ether (BDE-209) and Zn²⁺ (ZnSO₄·7H₂O) on the activity of soil enzymes (catalase and saccharase) and soil respiration during 93day incubation. The results indicated that catalase and saccharase showed high sensitivities to single and combined pollution of BDE-209 and Zn²⁺ in a short term (1-7 d). With the extension of exposure time, the activities of catalase and saccharase showed a trend of gradual recovery even up to control levels. But the activities of catalase and saccharase in the treatment with the highest concentration of 100 mg·kg^-1 BDE209 combined with the highest concentration of 1000 mg·kg^-1 Zn²⁺ were always in inhibited states. The effects of combined pollution of BDE209 and Zn²⁺ on soil catalase activities were characterized by antagonism in the early exposure and dominated by synergy in the later exposure, and the effects on soil saccharase showed additive, antagonistic and synergistic interactions at different times. The effects of combined pollution of BDE209 and Zn²⁺ on soil respiration presented a pattern of “promotionsuppressionpromotionsuppression”, and the intensity of promotion or suppression decreased as the exposure time increased.

Soil erosion and available nutrient losses from two typical soils under simulated rainfall conditions.

MA Guang-yu1, LI Jia-wei1, FANG Qing-qing1, JIANG Hong2**

2015, 34(8):  2267-2273. 

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Two contrasting soils (Burozems and Cinnamon) were selected from northern China and eight simulated rainfalls were applied on the flumes with different conditions (two rainfall intensities: 60 and 120 mm·h^-1; two slopes: 10° and 20°). The impacts of rainfall intensity and slope on available N (AN) and available P (AP) losses were studied. The result showed that the soil erodibility of Cinnamon was much higher than that of Burozems. The higher soil erodibility of the Cinnamon soil resulted in greater runoff, soil loss and AN and AP losses. The influence of runoff on sediment was positively linear (R²>0.398, P<0.01). The absolute slope of the regression line between runoff rate and sediment yield rate was suitable as a soil erodibility indicator. The AN and AP losses were influenced by runoff rate and sediment yield rate (P<0.01). Soil erodibility significantly influenced the AN and AP loss rates (P<0.01) and a positive logarithmic correlation best described their relationships.

Correlation between soil physicochemical properties and fungiderived glomalinrelated soil proteins in agricultural region of Songnen Plain.

ZHONG Zhao-liang, WANG Wen-jie**, WANG Qiong, WU Yan, WANG Hui-mei, PEI Zhong-xue, REN Jie

2015, 34(8):  2274-2280. 

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Study on correlation between soil physicochemical properties and fungiderived glomalinrelated soil proteins (GRSP) at different depths is helpful to uncover the role of soil fungi in different soil layers. In this paper, 360 soil samples were collected at 5 different depths (0-100 cm) in Songnen Plain cropland to analyze EE-GRSP, T-GRSP, 11 soil  physicochemical properties and their correlations. EE-GRSP and T-GRSP contents were 0.74 and 6.0 mg·g^-1 in surface soil, respectively, and both declined significantly with the soil depth. Moreover, the deeper soil layer (40-100 cm) stored 41.2%-62.8% of SOC, total N, total P, total K, alkalinehydrolyzed N, available P, and available K at 0-100 cm. Soil pH, bulk density, moisture and electrical conductivity also had obvious vertical variation patterns. Obvious differences of correlations between various soil physicochemical properties and GRSP (EE-GRSP, T-GRSP) were found in different soil layers. A significant correlation between SOC and GRSP was found in all layers, and a significant correlation between soil pH and GRSP (P<0.01) was found in all layers except 0-20 cm. Most physicochemical properties  were correlated with EE-GRSP and T-GRSP at 60-80 cm and 20-60 cm, while few of such correlations were found in surface soil. These results showed that GRSP may have better correlations with soil properties in deeper soil layers than in surface layer, which affects the function of GRSP in regulating soil nutrients at different depths. We propose that planting deeprooting ligneous plants that have symbiosis with soil fungi is helpful for bioremediation of nutrientaffluent deeper soil layers.

Changes in the hydrological functions of litter layer following Phyllostachys edulis expansion into evergreen broadleaved forest.

SONG Qing-ni1,2, YANG Qing-pei1**, OUYANG Ming1, LONG Chun-ling1, CHEN Fu-sheng1, SHI Jian-min1

2015, 34(8):  2281-2287. 

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The expansion of Phyllostachys edulis into neighbor secondary evergreen broadleaved forest may affect the hydrological functions of litter layers. Using laboratory simulated rainfall experiments and immersion test, we monitored the time of retarding runoff, rainfall interception and water holding capacity of litter between Ph. edulis forest (PEF) and adjacent evergreen broadleaved forest (EBF). When the rainfall intensities were 0.5, 1.0, 1.5 mm·min^-1 and the slopes were 10°, 25°, 40°, the time of litter retarding runoff decreased with the rainfall intensity and the slope, with the time of retarding runoff for PEF being higher than that for EBF. The relationship between interception capacity and rainfall time could be described by N_t=N₀(1-e^-kt) for both stands, and the maximum interception capacity (N₀) of litter layers increased with the rainfall intensity but decreased with the slope. Under the same condition, PEF had higher N₀ than EBF. The maximum water holding capacity rate was 267.51% for PEF, being 9.49% higher than that for EBF (244.33%); the maximum water holding capacity for PEF (7.41 t·hm^-2) was 40.60% higher than that for EBF (5.27 t·hm^-2). These results indicated that the hydrological functions of litter layer may increase with the expansion of Ph. edulis.

Using boosted regression trees to analyze the factors affecting the spatial distribution pattern of wildfire in China.

JIAO Lin-lin1,2,3, CHANG Yu1**, SHEN Dan1,3, HU Yuan-man1, LI Chun-lin1, MA Jun1,3

2015, 34(8):  2288-2296. 

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Determining factors that affect the spatial distribution pattern of wildfires has significant implications for wildfire prediction and fire risk zonation, and could also provide scientific basis for making rational wildfire management decisions as well. We chose five factors including annual average temperature, mean annual precipitation, elevation, vegetation type and population density, and utilized boosted regression tree (BRT) method to analyze the main factors that influence the spatial distribution pattern of burned area and the number of fires from 2006 to 2011. Results showed that the factor most affecting the spatial distribution of burned area according to its relative contribution was elevation (36.92%), followed by annual average temperature (27.85%), mean annual precipitation (13.17%), population density (13.00%) and vegetation type (9.07%). In general, climate and elevation determined the spatial distribution pattern of burned area. The factor most affecting the spatial distribution of the number of fires according to its contribution was population density (27.44%), followed by elevation (25.97%), vegetation types (22.84%), annual average temperature (18.98%) and mean annual precipitation (4.77%) according to their relative contributions. Human activities together with topography and fuels determined the spatial distribution pattern of the number of fires. We suggested that, in addition to climate and vegetation factors, topographic factors especially elevation should be included when making national wildfire risk zonation; and that the management of field fire use should be strengthened and fuel treatment be performed to reduce the occurrence of wildfires.

 

Chemical weathering in the Three Rivers (Jingshajiang, Lancangjiang, and Nujiang) Watershed, Southwest China.

TAO Zheng-hua1,2, ZHAO Zhi-qi1**, ZHANG Dong1,3, LI Xiao-dong1, WANG Bao-li1, WU Qi-xin1,4, ZHANG Wei1,5, LIU Cong-qiang1

2015, 34(8):  2297-2308. 

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The Three Rivers (Jinshajiang River, Lancangjiang River, and Nujiang River) region (TRR) in Southwest China was selected to study the characteristics of chemical weathering during river erosion. With the forward model, hydrochemical characters and dissolved inorganic carbon isotopes of river waters were used to interpret the sources and their corresponding contributions to dissolved components, and to confirm the participation of sulfuric acid in carbonate weathering and the net release of CO₂. The results showed that: (1) Hydrochemical compositions of river water were controlled by complex lithology. The ions of NaCa-Cl-HCO₃ were dominated in Jinshajiang River due to outcrop of evaporates in its upstream region, while Ca-HCO₃ was dominated in Lancangjiang River and Nujiang River due to the existence of abundant carbonate and silicate minerals; (2) Sources and ratios of dissolved components in river waters in TRR were variable. The dissolution of evaporates might control the sources of ions in the main stream of Jinshajiang River with an average percentage of 52%, but was minor in Lancangjiang River and Nujiang River with an average percentage of 11% and 2%, respectively. On the contrary, the dissolution of carbonates controlled the sources of ions in the main stream of Lancangjiang River and Nujiang River with an average of 70% and 78%, respectively, and was minor in the main stream but considerable in major tributary drainage of Jinshajiang River with a corresponding average of 38% and 74%. In addition, the contribution ratios of silicates weathering to the main streams of Jinshajiang River, Lancangjiang River and Nujiang River were 8%, 16%, and 15% respectively; (3) The weathering rates of silicates in the catchments of Jinshajiang River, Lancangjiang River and Nujiang River were 1.14, 3.32 and 4.32 t·km^-2·a^-1, respectively, and the corresponding CO₂ consumption rates were 0.35, 1.19 and 1.41×10⁵ mol·km^-2·a^-1. By contrast, the weathering rates of carbonates in the three studied rivers were 17.41, 34.04 and
34.84 t·km^-2·a^-1 with the CO₂ consumption rates of 1.46, 2.69 and 2.53×10⁵ mol·km^-2·a^-1 respectively; (4) Sulfate in the TRR was mainly derived from sulfide oxidation which led to net release rates of CO₂ as 0.87, 3.01 and 4.36×10⁵ mol·km^-2·a^-1 in Jinshajiang River, Lancangjiang River and Nujiang River, respectively. These values were higher than those in Guizhou, China, so attention should be paid to the important role of sulfuric acid in rock weathering during the study of regional carbon cycle and global climate change.

Spatial-temporal characteristics and impact factors of land surface temperature of Five Southern Islands of Miaodao Archipelago, Shandong, China.

CHI Yuan1, SHI Hong-hua1**, WANG Xiao-li2, FENG Ai-ping1

2015, 34(8):  2309-2319. 

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Island ecosystem has the characteristics of vulnerability and selfcontainment due to its limited area and isolated space, and land surface temperature (LST) is of greater importance to surface energy balance and resources/environmental changes on island. In this study, Five Southern Islands of Miaodao Archipelago were used as the study areas and a LST model was established based on splitwindow algorithm and regional characteristics. Then, the values of LST in different seasons, of different islands and under different types of land cover were calculated using methods of RS and GIS, and NDVI, altitude, slope, aspect and soil water content were adopted to reveal the factors impacting LST. The results showed that the mean values of LST in spring, summer, autumn and winter were 12.05, 32.93, 13.91 and 7.76 ℃, respectively, and the annual mean value of LST was 16.66 ℃. The annual mean values of LST of the different islands showed the following descending order: Nanchangshan Island > Beichangshan Island > Miao Island > Daheishan Island > Xiaoheishan Island, which displayed the maximum difference of 1.89 ℃. The types of land cover included construction land, farmland, broadleaf forest, grassland, bare land and coniferous forest land in the descending order of annual mean value of LST, and displayed the maximum difference of 1.63 ℃. The differences in land cover characteristics were the main cause of the differences in LST of different islands and the annual mean value of LST was positively associated with the proportion of construction land. NDVI, altitude and slope together influenced LST, and showed a significant negative correlation with LST in the whole year and spring, summer, autumn, and a significant positive correlation with LST in winter. Aspect independently influenced LST, which showed a significant positive correlation with LST during the whole year and each season. Soil water content derived by field investigation at 57 sampling sites had no obvious relationship with NDVI but was positively correlated with LST, which were probably caused by features of typical island ecosystem of Five Southern Islands.

Evaluation and zoning of ecological conservation of the Hanjiang lakeside district in Yangzhou.

ZHANG Shan-shan1,2, ZHANG Luo-cheng1**, DONG Ya-wen1, CHEN Xiao-fei1,2, ZHAO Jin-li1,2

2015, 34(8):  2320-2326. 

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Hanjiang district in Yangzhou City was divided into a series of ecological units (500 m×500 m), and then the ecological conservation of each unit was evaluated through multifactor comprehensive analysis method based on five ecological elements including drainage component index, water conservancy facilities index, water quality target index, index of farmland ratio, and ecological red line control index. Four ecological constraint levels (highest, high, general, and low) were used to indicate ecological conservation, and their area occupying ratios were 7.36%, 25.76%, 43.22% and 23.66%, respectively. The study area was classified into four subfunction zones including potential development zone, reserved zone, transition zone, and protection zone, and they accounted for 10.33%, 40.66%, 36.04% and 12.97%, respectively. The evaluation results of ecological conservation of Hanjiang lakeside district in Yangzhou City is of great significance for promoting a balance between its ecological protection and economic development.

Is vetiver grass planted in China an invasive alien species and becoming a weed?

XIA Han-ping1**, WANG Ming-zhu2, XU Li-yu2

2015, 34(8):  2327-2332. 

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The Vetiver Grass Technique (VGT) was introduced into China in 1988 via Mr. Richard Grimshaw, the Chairman of International Vetiver Network. It is an excellent ecoengineering and phytoremediation technology that has been used for the purposes of soil and water conservation, environmental protection, habitat restoration, disaster and pollution control and so on. In the last two decades, VGT has been applied to over a dozen of provinces in southern China, and has made significant ecological and social benefits. As a matter of fact, before it was introduced into China, “wild” vetiver had already existed in Hainan, Guangdong, Fujian for long time, which can be traced back to 1936. However, there has not been conclusive evidence or information so far whether the vetiver is native to China or imported from abroad. At present, the only reproduction method of the cultivated vetiver around the globe is through asexual means (e.g., tillering), and vetiver sprawl and “repellent” phenomena haven’t been found in China. In contrast, vetiver can improve harsh habitat conditions and therefore benefits the growth of other native species, which subsequently leads to the shrinking or even disappearance of vetiver due to its poor tolerance to shade. In addition, vetiver is particularly sensitive to herbicides, and therefore, often can be completely annihilated by the spraying of herbicides. In conclusion, there is no scientific basis to conclude that vetiver is an alien invasive species and has potential to become a weed.

 

Research progress on molecular microbial ecology associated with shale gas exploration.

ZHANG Yi-meng1, YU Zhi-sheng1**, ZHANG Yi-ming2, ZHANG Hong-xun1

2015, 34(8):  2333-2338. 

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Shale gas, due to its large reserves worldwide and green nature, has drawn extreme attention in recent years in energyrelated research. Microorganisms play important roles in the formation and exploration of shale gas. Studies of the molecular microbial ecology associated with shale gas can help to better understand the mechanism of shale gas formation and management of gas production and wastewater treatment. The current paper is a review on research progresses in the stated areas, including shale gas genesis, pathways of methane formation, effects of environmental factors on methane formation, impacts of drilling mud and hydraulic fracturing liquids on microorganisms, and the existence of microbial communities on production facilities. A better understanding of microbial ecology in the production facilities of deep shale gas wells and how commercial exploration affects the subsurface microorganisms would help extract the valuable shale gas resources.

Breeding, restocking and culture of Gloiopeltis: A review.

GUO Yong-jian1, ZHANG Wen-wen1,2, LI Jun-wei1, ZHU Chang-bo1, XIE Xiao-yong1, GUO Yi-hui1, CHEN Su-wen1**

2015, 34(8):  2339-2343. 

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The extracts of algae, Gloiopeltis, have been widely used in chemical, medical and food industries; however, overexploitation has caused the scarcity of Gloiopeltis resources. Largescale culture of Gloiopeltis is important to solve the shortage of natural source of Gloiopeltis, while our understanding of Gloiopeltis is obviously lagged behind that of other economic algae. The current review evaluates the spatial distribution and presents the reproductive biology of Gloiopeltis, including the life cycles, reproductive modes, storage methods and spore germination. We describe several ecological and physiological factors that affect spore release, attachment, germination and survival, as well as algae growth, reproduction and survival. Moreover, we describe the status of research and application of Gloiopeltis propagation. We suggest that finding and breeding new varieties of Gloiopeltis with high temperature resistance and superior growth traits is of great significance for future Gloiopeltis aquaculture.

Simulation of net primary productivity by a satellite data-driven improved CASA model in Xilingol grassland.

YANG Yong1, LI Lan-hua2, WANG Bao-lin2, SONG Xiang-yang2, LIU Ai-jun2**, WANG Ming-jiu1**

2015, 34(8):  2344-2352. 

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We improved the parameters of the maximum solar energy utilization efficiency and water stress coefficient algorithm of the original CASA model. The improved CASA model was verified by simulating the net primary productivity (NPP) of Xilingol grassland in 2010. Our results show that the improved CASA model could estimate small scale vegetation NPP in Inner Mongolia grassland, with significant correlation between simulated NPP and observed data (R²=0.829, P<0.05). On average, NPP in growing season (AprilOctober) of Xilingol grassland in 2010 was 284.64 g C·m^-2·a^-1. NPP was considerably different among different regions. For example, NPP was up to 411.11 g C·m^-2·a^-1 in Ujimqin grassland and 158.87 g C·m^-2·a^-1 in Erenhot City grassland. Consistent to the trend of regional water and heat variation, NPP of Xilingol grassland decreased from east to west. There were two peaks in the temporal pattern of NPP due to lag effect of precipitation. NPP in 2010 varied among different grassland types and was mostly in the range of 250-350 g C·m^-2·a^-1, in which the NPP of meadow steppes was the highest, followed by typical steppes, while NPP of desert steppes was the lowest.

Comprehensive assessment of soil habitat quality of severely burned forest land in Greater Xing’an Mountains.

SONG Li-chen1, HE Ping-ping2, CUI Xiao-yang1**

2015, 34(8):  2353-2361. 

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In this study, the changes of soil habitat factors of the severely burned forest lands and the unburned forest lands in Greater Xing’an Mountains were monitored for three years to assess soil habitat quality. The corresponding soil quality indices (SQI) were obtained by calculating the memberships and weight values of soil habitat factors. The results showed that, SQI could visually reflect the effect of forest fire on soil quality. However, the obtained assessment results were not consistent due to the different soil habitat factors applied. The results obtained from 12 soil habitat factors showed that the soil habitat quality of burned lands was gradually increased over time. The results obtained from 7 soil functional factors showed that the soil habitat quality decreased slightly after fire, and then increased over time. When 3 obstacle factors were applied, the assessment results showed that soil habitat quality decreased obviously after fire and sharply increased late. Therefore, the obstacle factors should be chosen to assess the quality of forest soil habitat suffering from fire both instantly and after long time (more than 3 years). Such assessment method could reduce the workload for obtaining information of soil habitat factors, and also avoid overestimating the soil habitat quality of burned soil due to the hidden constraint factors. The results of this study could provide useful reference for the management and restoration of burned forest land.

Ecosystem health assessment of Yellow Sea and Bohai coastal areas.

SHEN Dan1,2, JIAO Lin-lin2, CHANG Yu1**, HU Yuan-man1, LI Ze-ming1, SHI Ya-juan3, Wang Tie-yu3

2015, 34(8):  2362-2372. 

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Environmental issue has received more attentions with development of the society and economy. Recently, ecosystem health assessment has been considered as a hot topic in the field of ecological environment. In this paper, we took the Yellow Sea and Bohai coastal areas, covering 131 counties, as the study area, and evaluated health level in each county that is identified as an individual evaluation unit. According to the latest data involving society and economy, we established the ecosystem health assessment model under the framework of PressureStateResponse (PSR). Multiple factors were taken into account in this model, including the population, society, economy, environment, landscape pattern and policy. Furthermore, we calculated the ecosystem health index in each county by the established model. The results showed that ecosystem heath levels in 84.73% of the study area reached the qualified level or above, indicating that the overall ecosystem in the Yellow Sea and Bohai coastal areas was relatively healthy and has selfadjustment ability resisting to natural and anthropogenic disturbances. Finally, this paper also analyzed the potential pressures threatening the ecosystem and provided suggestions for improving the ecosystem heath.

Temporal and spatial variations of the drought in Ningxia based on aridity index and Morlet wavelet analysis.

ZHANG Yan-long, LIU Pu-xing**, WANG Yun

2015, 34(8):  2373-2380. 

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Based on the climate data of daily temperature, precipitation, wind speed, sunshine hours as well as relative humidity at nine meteorological stations in Ningxia during 1961-2012, evapotranspiration (ET₀) was estimated by the PenmanMonteith model. Additionally, inverse distance weighting was applied to investigate the temporalspatial variations of ET₀, precipitation and aridity index. The abrupt change and the period in ET₀, precipitation and aridity index were characterized using a time series analysis conducted with moving ttest and Morlet wavelet. The results showed that in recent 52 years, the ET₀ and precipitation presented a decreasing trend on the whole with rates of -8.64 mm·10 a^-1 and -10.04 mm·10 a^-1, respectively; aridity index displayed a slightly increasing trend (0.01 10 a^-1), suggesting a drier climate trend in Ningxia. Moreover, both the ET₀ and precipitation exhibited a unimodal type of distribution with peaks appearing in August (66.82 mm) and July (118.12 mm), respectively, and aridity index showed a valleylike type with minimum (0.42) in August. For spatial distribution of the aridity index, it presented an increasing trend from south to north, suggesting that climate got drier from south to north. Abrupt changes of ET₀, precipitation and aridity index primarily happened in the late 1970s, early and midterm 1980s, and the large time scales of these abrupt changes were same (21 a) and in agreement with the period (22 a) of sunspot activity. Besides, their fluctuations in the short periods of 3, 5 and 7 years were correlated to atmospheric circumfluence and El Nino
events to some extent.