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Table of Content

    08 January 2011, Volume 30 Issue 01
    Articles
    Characterization of (GT)n microsatellite in Anodonta woodiana genome.
    2011, 30(01):  1-6. 
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    The method of magnetic-bead hybridization enrichment was used to isolate the microsatellite loci of Anodonta woodiana. Genomic DNA was digested with restriction enzyme Sau3A1. The fragments were hybridized with biotin-labeled (GT)15 probe and captured by streptavidin-coated magnetic beads. The target fragments were inserted to PGEM-T vectors, and positive clones were obtained through PCR screening the library. By isolating the (GT) microsatellite in A. woodiana genome, 180 positive clones were sequenced, 37 sequences contained microsatellite having at least 5 times repeats numbers (20.6% of white colonies screened). From the microsatellites sequence, the two bases repeat arrays were most abundant, accounting for 86.4%, among which, 32.0% were perfect repeats, 10.0% imperfect repeats, 8.0% compound repeats, and 50.0% the combination of imperfect repeats and compound repeats. The largest repeat number of perfect type microsatellite was 65. This allowed us to design 30 pairs of primers from 37 microsatellite sequences. As a result, 11 pairs were screened and used successfully to amplify polymorphic fragments.
    Sexual dimorphism of Shinisaurus crocodilurus.
    2011, 30(01):  7-11. 
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    Through comparing the body size and head size among juveniles and female and male adults, the sexual dimorphism of Shinisaurus crocodilurus was studied. There was a significant difference in the ventral color of head and breast between the adults, i.e., vivid red or light blue for the males, and light yellow or light red for the females. The head size (including head width (HW) and head length (HL)) of the males were significantly larger than those of the females (HL, P<0.001; HW, P<0.001), and the abdomen length (AL) of the males was significantly shorter than that of the females (P=0.018). However, the snout-vent length (SVL) and tail length (TL) between the males and females were not significantly different (for SVL, P=0.193; for TL, P=0.22). The increasing rate of HL with SVL for the juveniles was higher than that for the female adults (P=0.021), whereas the HW was not significantly different between the juveniles and female adults (P=0.545). The head size of both the juveniles and the male adults increased with SVL at the same rate (for HL, P=0.252; for HW, P=0.441). When the SVL was kept constant, the HW of the juveniles was larger than that of the female adults (P<0.001), and the HL of the juveniles was larger than that of the male adults (P<0.001), but the difference of HW between the juveniles and the male adults was not significant (P>0.05). The results indicated that partial sexual dimorphism existed in S. crocodilurus.
    Distribution and biotransformation of DDTs and HCHs in Hemifusus tuba from the southern Pearl River Estuary.
    2011, 30(01):  12-17. 
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    Based on the measurements of DDTs and HCHs concentrations in various tissues of Hemifusus tuba from the southern Pearl River Estuary, the distribution and biotransformation of the two organochlorine pesticides (OCPs) in this marine gastropod were examined. The DDTs and HCHs concentrations in H. tuba intestine were much higher than those in other tissues, suggesting that the intestinal wall of H. tuba was an important barrier to DDTs and HCHs. The higher DDTs and HCHs concentrations in H. tuba gonad suggested that the gonad was an important site for the accumulation of DDTs and HCHs. The (DDE+DDD)/p,p′-′DDT ratio in various H. tuba tissues (3.20-7.53) was much higher than that in sediment (123), indicating that H. tuba had stronger capability to metabolize DDT. The highest (DDE+DDD)/p,p′′-DDT ratio was found in gill, suggesting that gill could play an important role in excreting the DDT metabolites (DDD and DDE) in H. tuba. Among the HCHs in all H. tuba tissues, β-HCH was the most persistent HCH isomer (63.88%-88.99%), implying that H. tuba was able to efficiently degrade α-HCH to β-HCH. Though the DDTs and HCHs concentrations in H. tuba muscles did not exceed the tolerable daily intake standard proposed by the WHO, more attention should be paid to the potential risks of OCPs biomagnification along food chain to human health.
    Habitat characteristics favored by forest musk deer (Moschus berezovskii) in summer in Liangshan Mountains.
    2011, 30(01):  18-23. 
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    A transect investigation was made from June to August 2005 to study the habitat characteristics favored by forest musk deer (Moschus berezovskii) in summer in Dafengding National Natural Reserve in Liangshan Mountains of Sichuan Province, Southwest China. A total of 44 M. berezovskii-favored plots (20 m×20 m) and 209 non-favored plots (20 m×20 m) were sampled to compare 14 habitat variables. The variables were recorded as continuous factors such as elevation and shrub canopy and discrete variables such as slope position and water-source dispersion. The results showed that in summer, M. berezovskii preferred the habitats with lower proportions of arbor canopy (32.4%±1.9%), shrub canopy (27.1%±2.4%), and bamboo canopy (40.8%±3.0%), and higher proportion of rocky area (18.3%±1.6%) predominantly situated on eastern and southern slopes (81.8%). In comparison, the corresponding habitat variables for non-favored plots were 50.5%±1.0%, 39.7%±1.2%, 59.1%±1.0%, and 1.5%±0.4%, respectively. Principal components analysis (PCA) indicated the most important factor affecting M. berezovskii habitat selection was vegetation factor (including bamboo height, vegetation type, and shrub canopy). During summer, M. berezovskii predominantly selected conifer-broadleaf forest (11.4%) and conifer forest (88.6%) with certain shrub canopy (27.1%±2.4%) and bamboo canopy (1.76 m±0.08 m). In addition, topographic factor (including elevation and slope gradient), water-heat factor (including slope aspect and water-source dispersion), and habitat-ground factor were also important in determining the habitat characteristics favored by M. berezovskii in summer.
    Assemblage characteristics of dung beetles in livestock dung in |Inner Mongolian typical steppe.
    2011, 30(01):  24-29. 
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    From June 2008 to September 2009, an investigation was made on the species diversity, population structure, functional group, and feeding preference of dung beetles in the fresh dung of horse, cattle, and sheep in  Inner Mongolian typical steppe. A total of 7805 dung beetles were captured, belonging to 3 families, 4 genera, and 32 species. Aphodius comma, A. erraticus, and A. sordecens were the dominant species, with their individual number occupied 42.62%, 13.26%, and 11.64% of the total, respectively. In the fresh livestock dung, there were 3 kinds of functional groups, i.e., telocoprid, paracoprid, and endocoprid, among which, endocoprid had the highest numbers of species and individuals. The richness index of the dung beetle assemblage was the highest in horse dung, Shannon index was the highest in cattle dung, and evenness index was the highest in sheep dung. The dung beetles had obvious feeding preference to the 3 kinds of livestock dung, and most of them preferred fresh horse- and cattle dung.  Horse dung pats had bigger volume, moderate water content, more undigested plant fiber, and easy dryness, being able to supply moderate and temporary habitat for the feeding activity of endocoprids; while cattle dung pats had higher water content, slower water-losing, and easy breaking-up, being the longer term micro-habitat for most paracoprids. Obviously, the habit preference of the dung beetles was mainly related to the characteristics and availability of livestock dung, and also, related to the biological and ecological features of the dung beetles.
    Effects of ground cover on the niches of main insect pests and their natural enemies in peach orchard.
    2011, 30(01):  30-39. 
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    Taking the peach orchards with and without ground cover Trifolium repens as test objects, an investigation was made on the quantities of main insect pests and their natural enemies on peach trees, with the niches of the insect pests and natural enemies measured. Among the main insect pests, Aromia bungii-in the peach orchard with ground cover T. repens had the widest horizontal niche breadth (0.999), Halyomorpha halys had the widest vertical niche breadth (0.964) and widest time niche breadth (0.795), while the corresponding values in the orchard without T. repens were 0.918, 0.792, and 0.632, respectively. Among the natural enemies, spiders in the peach orchard with ground cover T. repens had the widest horizontal niche (0.996), widest vertical niche (0.983), and widest time niche (0.932), while the corresponding values in the peach orchard without T. repens were 0.900, 0.800, and 0.818, respectively. The three-dimensional niche of the main insect pests in peach orchard with ground cover T. repens was Halyomorpha halys> Cicadellidae > Fulgoridae > Aphididae > Lyonetia clerkella > Dichocrocis punctiferalis > Aromia bungii > Grapholitha molesta > Pseudaulacaspis pentagona, while that in the peach orchard without T. repens was Aphididae > Cicadellidae > Halyomorpha halys > Aromia bungii > Grapholitha molesta > Fulgoridae > Pseudaulacaspis pentagona > Lyonetia clerkella > Dichocrocis punctiferalis. The three-dimensional niche of the main natural enemies in peach orchard with ground cover T. repens was spider > Orius spp. > Chrysopa > parasitic wasp > Coccinellidae > Syrphidae, while that in the peach orchard without T. repens was spider > Chrysopa > Coccinellidae > Parasitic wasp > Orius spp. > Syrphidae. The Orius spp., Coccinellidae, Syrphidae, and parasitic wasp in the peach orchard without T. repensall showed an evidence of delayed activity. The three-dimensional niches of natural enemy Orius spp. and main insect-pests overlapped greater in the orchard with T. repens than in that without T.repens, and the temporal synchrony and spatial similarity of natural enemies and insect-pests were overall superior in the orchard with T. repens. Our results showed the positive effect of planting clover as ground cover on the biological control of insect pests in peach orchard.
    Community composition and its characteristics of ballooning spiders in east Liaoning Province of Northeast China.
    2011, 30(01):  40-44. 
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    Suction traps were used to investigate the community composition and its characteristics of ballooning spiders in Xiuyan Region of Liaoning Province,Northeast China from May to September 2009. A total of 549 specimens of ballooning spiders were captured, belonging to 14 families. The analysis of the community composition, seasonal dynamics, body lengths, growth phases, and sexual ratio of the specimens showed that the species richness of the ballooning spiders in east Liaoning was abundant, and Linyphiidae and Araneidae were the dominant groups, occupying 58.29% and 11.84%, respectively. In all mature individuals, the most abundant families were of Linyphiidae (74.02%) and Tetragnathidae(11.02%). The ballooning behaviors were observed throughout the investigation period. ANOVA analysis indicated that the number of ballooning spiders collected in early August to  early September was significantly higher than that in other periods. The ballooning spiders had a body length less than 8 mm, and 91.44% of them had a length less than 3 mm. The χ2 test revealed that the individuals at immature stage were significantly higher than those at adult stage, and the male individuals were significantly higher than the females.
    Species diversity and spatial differentiation of ephemeral plant community in southern Gurbantunggut Desert.
    2011, 30(01):  45-52. 
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    Ephemeral plants are a special type of plants living in an environment which is rainy in early spring and xerothermic in summer.  In Gurbantunggut Desert, they  are mainly distributed in the southern part, playing an important role in the maintenance of desert ecosystem stability and in sandfixation. However, few studies have been done on their community diversity, ecological function, and spatial distribution. By adopting stratification sampling, this paper investigated the diversity feature of ephemeral plants at 35 sites covering a total area of 3.86×104 m2 in the southern Gurbantunggut Desert. A total of 93 ephemeral species were recorded, belonging to 24 families and 74 genera, among which, Chenopodiaceae, Compositae, Cruciferae, and Leguminosae were the dominant families, accounting for 19.35%, 17.20%, 11.83%, and 9.68% of the total species, respectively. In terms of life form, ephemeral plants, annuals with long period of nourishment, and trees and shrubs accounted for 53.76%, 22.58%, and 16.13%, respectively. In terms of importance value, ephemeral plants accounted for 45.73%, while trees and shrubs accounted for 30.93%. Ephemeral plants had a distinct spatial differentiation. Their species number and importance value increased obviously with longitude (from west to east), but decreased with latitude (from south to north). Oppositely, annuals with long period of nourishment and trees and shrubs had a decreasing importance value with longitude (from west to east), and their importance value increased with latitude (from south to north) but species number had no distinct change with latitude. Detrended canonical correspondence analysis (DCCA) showed that the species distribution was greatly affected by slope position, longitude and latitude, annual precipitation, and the precipitation from March to May. Based on two-way indicator species analysis (TWINSPAN), the ephemeral plants in southern Gurbantunggut Desert were divided into seven communities. It was considered that, with the increase of the precipitation in Gurbantunggut Desert, the importance value and species number of ephemeral plants tended to increase, but the density of dominant species Haloxylon persicum would be decreased gradually.
    Life table of natural Ginkgo biloba population in Tianmu Mountain Nature Reserve.
    2011, 30(01):  53-58. 
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    Based on the population life table and the theory of survival analysis, the static life table of Ginkgo biloba population in Tianmu Mountain Nature Reserve of Zhejiang Province was compiled by applying the age class structure represented by DBH class and the smoothing out technique. The mortality rate curve, killing power curve, survival rate curve, and survival function curve were also analyzed to reveal the population’s quantitative dynamics. There was a fluctuation in the structure of G. biloba population. The survival curve of the population tended to the type of Deevey Ⅱ, and the individuals at adult stage were abundant. The mortality rate curve and killing power curve in the lifespan had similar variation trend, all with the peaks in 6th and 11th age class periods. The survival rate of the population decreased monotonically, whereas the cumulative mortality rate was in adverse. The survival functional curve showed that the G. biloba population grew poorly in early age period and stably in middle age period, but declined in old age period.
    Harmonic analysis on NDVI time series of typical land covers in Shandong Province.
    2011, 30(01):  59-65. 
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    Harmonic analysis, also termed Fourier analysis, is used to analyze time series data. It can decompose a time-dependent periodic phenomenon into a series of sinusoidal functions, each defined by unique amplitude and phase values. The harmonic analysis of NDVI time series can characterize the seasonal change of land cover. In this paper, a harmonic analysis was made on the 1-year MODIS NDVI time series data of Shandong Province, with the harmonic characteristics (additive term, amplitude, and phase image) of several typical land covers in the province extracted. The results showed that the original NDVI time series could be reconstructed by using several harmonic terms with low frequency, and the reconstructed time series profile was smoother, suggesting that harmonic analysis had removed noise when processing time series. Different land covers had different characteristic parameters of harmonic term, being correlated with the seasonal change of land cover. Additive term indicated the arithmetic mean of NDVI; amplitude indicated the variation of temporal NDVI; while phase image indicated the time of peak value. Each land cover had its different harmonic parameters. It was suggested that the results of harmonic analysis could be used for studying vegetation classification and vegetation dynamics.
    Effects of harvested wood products on forest carbon storage.
    2011, 30(01):  66-71. 
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    Forest is the largest carbon (C) pool in terrestrial ecosystem. Under the background of global warming, the influence of forest management on the C pool is increasingly drawing the attention of scientists all over the world. Most of the literatures in China consider that the harvested wood products (HWP) discharge C at current year, but actually, the C in HWP can be deposited for a long time. According to the usage and harvesting practices of HWP, the HWP were divided as 1) harvested residues (DBH ≤6 cm), and 2) solid wood products and paper products (DBH >6 cm). This paper investigated the DBH and tree species composition before and after harvesting in the broadleaved-Korean pine mixed forests in Changbai Mountain, and studied the dynamic changes of the forest C storage, based on the actual emission of C from HWP. The results showed that the C storage of harvested residues was 1.1 t C, and the C emission speed changed from fast to slow. The total C emission would last over 80 years. The C storage of solid wood products was 20.56 t C, and the cumulated C emission in 80 years reached 20.07 t C (97.71%). The C storage of paper products was 3.63 t C, and the cumulated C emission would reach 3.45 t C (95.13%) in the first 7 years. If the C emission from HWP was considered at current year, the forest C pool would take 20 years to reach the level before harvesting; if considering the actual C emission from HWP, the forest C pool would be always larger than the level before harvesting. Therefore, it would be reasonable and meaningful to consider the actual C emission from HWP so as to accurately estimate the forest C storage in China.
    Effects of salt stress on Suaeda heteroptera Kitagawa growth and osmosis-regulating substance concentration.
    2011, 30(01):  72-76. 
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    Salt stress inhibits plant growth, and its damage to plants differs with salt concentration. In this paper, a pot experiment was conducted to study the eco-physiological adaptability of Suaeda heteroptera Kitagawa under different salt conditions. The results showed that the inhibitory effect of salt on the growth of S. heteroptera seedlings increased with increasing salt concentration. Under low salinity stress, the fresh and dry weights and the water content of shoots and roots had no significant difference with the control; but under high salinity stress, the seedling growth was seriously affected, with more inhibition on shoots than on roots. When the NaCl concentration was lower than 200 mmol·L-1, there was a positive correlation between the free praline, soluble sugar, and protein contents in shoots and the salinity; when the NaCl concentration was higher than 300 mmol·L-1, there was a negative correlation between osmosis-regulating substance concentration and salinity.
    Characteristics of plant leaf nitrogen and phosphorus stoichiometry in relation to soil nitrogen and phosphorus concentrations in Songnen Plain meadow.
    2011, 30(01):  77-81. 
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    We measured total nitrogen (N) and total phosphorus (P) concentrations in leaves of Leymus chinensis, Phragmites communis and  Lespedeza hedysaroides in Songnen Plain meadow, and analyzed their relationship with soil total N and total P concentrations. The results showed that foliar total N concentration differed significantly among three species (P<0.05), while foliar total P concentrations did not show significant difference (P>0.05). The leaf N concentration of the three species had no significant correlation with soil total N concentrations (P>0.05), while the leaf N:P ratio was significantly negatively correlated with soil total P concentrations (P<0.05), suggesting that in our study area, different plant species had great difference in their leaf N concentration, but less difference in their leaf P concentration. Compared with leaf N and P concentrations, leaf N:P ratio was more related to soil N and P concentrations. In addition, the growth of Leymus chinensis and Lespedeza hedysaroides in study area was P-limited, and thereby, appropriate application of P fertilizer could be considered.
    Effects of applying sewage sludge on pakchois growth and transfer of heavy metals.
    2011, 30(01):  82-86. 
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    In a pot experiment, the sewage sludge from Xiamen Yundang Wastewater Treatment Plant was applied as organic fertilizer to study its effects on the growth and yield of pakchois and the transfer and accumulation of heavy metals in pakchois-soil system. The sludge was rich in nitrogen, phosphorus, potassium and organic matter, and its heavy metals contents were lower than the limits of national control standard for the pollutants in sludge for agricultural use. Appropriate application of the sludge could promote the growth and yield of pakchois. When the application rate was 5%, the pakchois had the maximum growth and biomass; but when the application rate was higher than 15%, the pakchois growth was remarkably inhibited. The root exudates of pakchois could fix and enrich the heavy metals in rhizosphere soil, and restrict their transfer into pakchois. The enrichment coefficients of test nine heavy metals in pakchois were all lower than 1.0. When the application rate of the sludge was 5%, the Cd, As, Ni, Pb, Cr, Cu and Zn contents in pakchois were all lower than the limits of national food hygiene standard of China. After planting pakchois, the chemical speciation of the heavy metals in rhizosphere soil transformed to some extent, e.g., the Cd and Cr transformed from residual form to bio-available, Cu and Zn transformed from oxidizable to acid-soluble, Mn and Pb transformed from reducible to oxidizable, while Ni appreciably transformed from bioavailable to residual.
    Bacterial diversity in rhizosphere soil of soybean: A comparison of RISA, DGGE, and 2D-PAGE techniques.
    2011, 30(01):  87-92. 
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    The PCR-based RISA, DGGE, and 2D-PAGE were adopted to analyze the bacterial diversity in rhizosphere soil of soybean. Most abundant soil bacterial diversity was acquired by 2D-PAGE (gene spots), followed by DGGE (gene bands), and by RISA (gene bands). The RISA gave the fewest bands, but the result was more stable and the experimental operation was more easy; DGGE obtained more bands and showed good precision, but had more error  sources; while 2D-PAGE as a novel soil microbial research method could overcome the low-resolution problem of the other two methods, achieve abundant information of soil bacterial diversity, and play an important role in the research of soil microbial ecology. However, the operation of 2D-PAGE was more complicated and required strict conditions, compared with RISA and DGGE. In spite of these disadvantages, 2D-PAGE had shown pote ntial advantages in the research field of soil microbial ecology.
    Effects of five arbuscular mycorrhizal fungi on the tolerance of trifoliate orange (Poncirus trifoliata (L.) Raf.)seedlings against zinc contamination
    2011, 30(01):  93-97. 
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    A pot experiment was conducted to study the effects of inoculation with arbuscular mycorrhizal (AM) fungi Glomus versiforme (G.v), G. mosseae (G.m), G. intraradices (G.i), G. aggregatum (G.a), and G. etunicatum (G.e) on the mycorrhizal colonization, growth, and zinc and phosphorus contents as well as some physiological indices in leaves and roots of trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings under zinc contamination. In zinc-contaminated soil, inoculation with G.i, G.e, or G.m increased the seedlings biomass significantly. The mycorrhizal colonization and mycorrhizal dependency were the highest with G.i inoculation, followed by G.e and G.v inoculation. Inoculation with AM fungi significantly decreased the shoot zinc content, and promoted the zinc accumulation in roots (except for G.a). The shoot/root ratio of zinc translocation coefficient was the lowest in treatment G.i, second lowest in treatment G.e, and the highest in treatment G.v. AM fungi inoculation increased the phosphorus content in roots significantly, and G.i inoculation also significantly increased the phosphorus content in shoots. Inoculation with G.i or G.e significantly decreased the MDA contents in leaves and increased the CAT activity and proline content in roots, but had little effects on the POD activity in roots, compared with the control. Our study showed that G.i inoculation was most beneficial to the tolerance of trifoliate orange against zinc contamination, followed by G.e, and G.v  inoculation.
    Effects of transgenic Bt maize on bacterial community structure in rhizosphere soil.
    2011, 30(01):  98-105. 
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    Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequence analysis were employed to assess the effects of transgenic Bt maize on the bacterial community structure and phylogeny in rhizosphere soil. In the rhizosphere soils of transgenic maize and its non-transgenic parents, most sequences were characterized by the members of Proteobacteria, Verrucomicrobia, Actinobacteria, Bacteroidetes, Firmicutes, Gemmatimonadetes, and Acidobacteria, among which, Proteobacteria was the dominant group, accounting for 43.5% of the total. The bacterial community structure in the rhizosphere soils of transgenic maize and its non-transgenic parents at different growth stages was highly similar, and had few different bands. Canonical correspondence analysis of the DGGE fingerprints and nutrient contents in rhizosphere soils of transgenic Bt maize and its non-transgenic parents revealed that the bacterial community composition was strongly correlated with soil total nitrogen, total phosphorus, and available nitrogen contents. Principal component analysis showed that the available nutrient contents and bacteria community structure in rhizosphere soils of transgenic Bt maize and its non-transgenic parents were very similar. In sum, there was no evident difference in the bacterial community structure in the rhizosphere soils of transgenic Bt maize planted for one year and of non-transgenic maize.
    Concentration and speciation distribution of mercury in forest soils on northern slope of Changbai Mountain
    2011, 30(01):  106-111. 
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    Soil samples were collected from the northern slope of Changbai Mountain in April and September 2009 to study the concentration and distribution of total mercury (THg) and methyl mercury (MeHg) in the soils under boreal forests at different altitudes. The THg and MeHg concentrations in the soil profiles ranged from 0.08-0.73 mg·kg-1 and 0.05-0.56 μg·kg-1, and the stocks were 97 kg·km-2 and 128 g·km-2, respectively, being higher than the background value of Jilin Province. Surface soil layer (0-10 cm) commonly had the highest MeHg concentration. There existed definite seasonal and spatial variations in the distribution of soil Hg. The gaseous Hg from wet and dry atmospheric depositions was the primary source of soil Hg in the study region.
    Landscape change and its driving forces in Hun-Tai river basin.
    2011, 30(01):  112-118. 
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    Based on the GIS/RS techniques and the methods of landscape ecology and Logistic regression, this paper analyzed the landscape change and its driving forces in Hun-Tai river basin from 1988 to 2004. The main landscape types in the river basin were forestland, shrub land, dry land, and rice field, but the land scape pattern changed greatly during the study period. The dry land and rice field decreased, forestland, water area, and rural and urban areas increased, while shrub land changed slightly. At landscape level, the landscape heterogeneity and fragmentation increased, while the patch spatial connectedness and landscape dominance decreased. The driving forces of the landscape change varied widely, among which, socio-economic forces played an important role, but the effect of natural forces could not be ignored.
    Seasonal variations and sources of pollutants in surface water of Hunhe River.
    2011, 30(01):  119-125. 
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    Water samples were collected from the upstream to the downstream of Hunhe River and its main tributaries in low flow period (April), flood period (August), and level period (November) in 2009, and the variations of their NH4+-N, total phosphorus (TP), and heavy metals concentrations within a hydrological year were analyzed, aimed to study the pollution characters and sources of the water bodies. It was found that in the downstream (Qijianfang-Yujiafang) of Hunhe River, NH4+-N had a high concentration (>1.5 mg·L-1), with the water quality belonging to level Ⅴ, but the TP concentration was lower, with an average of 0.16 mg·L-1. With the exception of Beizamu, Ajibu, Zhangdanghekou, and Yutai sites, the TP concentration at most sites was lower in level period (0.03-0.26 mg·L-1) and flood period (0-0.25 mg·L-1) than in low flow period (0.13-0.28 mg·L-1). The measurements of the NH4+-N and TP concentrations suggested that the water body of Hunhe River was more affected by the point source pollution of N and P. The Cu, Zn, Cd, and Pb concentrations in the surface water were 0.68-21.81, 43.33-129.00, 0.26-1.21, and 0-0.28 μg·L-1, respectively, suggesting that the Hunhe River was slightly contaminated by these heavy metals. Overall, the water body of Hunhe River was more seriously point source polluted by urban domestic sewage and industrial wastewater, and thus, the management of drainage point source, illegal drainage point in particular, should be strengthened.
    Anaerobic fermentation conditions of mixed corn straw and pig excreta in North China.
    2011, 30(01):  126-130. 
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    In order to promote the biogas generation during anaerobic fermentation of straw in North China, an anaerobic fermentation experiment with mixed corn straw and pig excreta was conducted. The total concentration of fermenting materials was controlled as 10%, and the quantity of inoculum was 20%. The biogas production was measured under the conditions of temperature 25 ℃and 35 ℃, straw granularity <1 cm, 1-3 cm, and 5-10 cm, and mass ratio of corn straw to pig excreta 1:1, 1.5:1, 2:1. The results showed that the daily and cumulative biogas productions were the highest under conditions of temperature 35 ℃, straw granularity 1-3 cm, and mass ratio of corn straw to pig excreta 1.5:1. These conditions could be used as the recommended parameters of anaerobic fermentation of mixed corn straw and pig excreta in North China countryside.
    Non-uniformity of precipitation distribution in Changbai Mountains in growth season.
    2011, 30(01):  131-137. 
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    Based on the 1960-2007 daily precipitation data from 13 meteorological stations in Changbai Mountains, and by using the concepts of precipitation concentration degree and precipitation concentration period, an analysis on the precipitation characteristics in this region in growth season was carried out, with the proposing of the index precipitation concentration point. In the study region, the average precipitation concentration degree in past years was 0.31, and its interannual and interdecadal variations were obvious. The precipitation concentration degree of 10-year quasi-period fluctuated markedly. There was an obvious spatial non-uniformity of precipitation concentration degree among the 13 meteorological stations. The average precipitation concentration period in past years was 84.6 d, also with obvious interannual and interdecadal variations. The average variance was 9.7 d, and the variation coefficient was 11.5%. An obvious spatial non-uniformity was also observed in the precipitation concentration period among the 13 meteorological stations, and the average variance was 10.9 d.
    Plant functional type and its application in ecosystem modeling.
    2011, 30(01):  138-144. 
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    Plant functional type is a new concept in studying the relationships between vegetation and global change at different spatial-temporal scales, and widely applied in the research field of plant ecology modeling. This paper introduced the concept of plant functional type and its resemblance and difference with life form, guild, and biome, summarized five common classification criteria of plant functional type, and highlighted the application of plant functional type in ecosystem modeling. In recent 50 years, the concept of plant functional type was applied in the following three aspects: 1) regional or global scale statistical modeling, 2) classic mechanism modeling, and 3) modeling how the ecosystem was affected by different classification criteria of plant functional type. The objective of this paper was to promote the resolution of the aggregation of plant functional groups in the up-scaling of ecosystem modeling.
    Epiphytic plants: Their responses to global change and roles in bioindication.
    2011, 30(01):  145-154. 
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    Epiphytic plants are a group of plants that live on host plants without absorbing nutrients and water from the hosts. Because of their specific morphological and structural features and ecological habits, epiphytic plants are very sensitive and vulnerable to environmental changes. To study the response of epiphytic plants to global change and their roles in bioindication has important guiding significance and application value. This paper reviewed the research progress in the possible responses of epiphytic plants to global change events, including atmospheric composition change, climate change, and land use/cover change, and summarized the related research methods. It was suggested that in the future, field control experiment and simulation study should be carried out by using standard and quantitative methods combined with the development and application of new instruments, the effective database should be built from long-term and systematic monitoring in global range, and the quantitative indices and corresponding models relating to the response of epiphytic plants to climate change should be developed.
    Adaptation of wetland plants to sedimentation stress: A review.
    2011, 30(01):  155-161. 
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    Sedimentation is a common phenomenon in wetlands. It generally increases soil bulk density, moisture content, and metal elements content, while decreases soil organic matter content, aeration condition, and temperature, giving effects on plant survival, growth, and vegetation succession. During the process of long-term adaptive evolution, wetland plants have evolved a series of efficient strategies to acclimate to sedimentation. Some plants have become so specialized that they actually require regular sand burial to maintain high vigor, while the others that don’t have effective strategies are disappeared. The main strategies include: 1) life history strategy, e.g., producing high-quality seed, seed dormancy, or enhanced clonal reproduction, 2) morphological responses, e.g., elongation of stem, leaf, or spacer, decreasing branching angle and root shoot ration, increasing tillers, and producing aerial roots, etc., and 3) physiological responses, e.g., enhanced photosynthetic rate, carbon dioxide exchange rate, and plant hormone level. Future research should focus on the mechanisms accounting for seed dormancy, plant performance, and physiological responses of plants to sedimentation. Meantime, anatomical study should be strengthened.
    Ecological remediation of contaminated soil: Theoretical connotation, measures, and applications.
    2011, 30(01):  162-169. 
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    This paper discussed the theoretical connotation of ecological remediation of contaminated soil, related measures, their optimal combination, and case applications. The goals of ecological remediation of contaminated soil were expanded as: Decreasing target pollutants to acceptable level, decreasing soil eco-toxicological properties to acceptable level, and recovering part or all soil ecosystem services. Five characteristics and five principles of ecological remediation of contaminated soil were summed up, and the principles of optimal combination of related measures were proposed. At present, the optimal combinations of related measures have the characteristics of taking plant and microorganism as the core and of simultaneous and asynchronous. In the case applications, the process of ecological remediation of contaminated soil is: Background investigation → improving basic environment conditions → bioremediation → evaluation. Though the optimal combination of related measures is the key in ecological remediation of contaminated soil, its mechanisms should be further studied. In addition, to promote the conversion of laboratory study to actual application is an inevitable problem in the studies of ecological remediation of contaminated soil. It is the foremost to further enrich and improve the theoretical connotation of ecological remediation of contaminated soil and to establish related theoretical framework.
    Comprehensive assessment of secondary geological disaster risk caused by Wenchuan Earthquake: Taking Chongzhou City as an example.
    2011, 30(01):  170-176. 
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    Wenchuan Earthquake brought about great amount of secondary geological disaster. To recognize the risk levels of this disaster in different areas of Wenchuan, this paper used post-disaster density of area weighted (HCA) as the index, and analyzed the corresponding relationships between various geological disaster-induced factors and disaster degree, taking Chongzhou City as an example. By using factor analysis to achieve the comprehensive hazard assessment, the study area was divided into five risk levels. The basic security area accounted for 53.61% of the total, most of which distributed in eastern plain region. Low risk area distributed in hilly region. Moderate and sub-high risk areas accounted for 19.58 % and 16.22%, respectively, and distributed in the mountainous and high rift zone density regions. High dangerous area was 37.82 km2, accounting for 3.5% of the total, where the secondary geological disaster was easily occurred, and thereby, most concern should be paid. Comparing with the traditional method based on disaster density (HC), the method based on HCA had an obviously higher accuracy.
    Observation and simulation of soil unsaturated hydraulic conductivity in mountain region of upper Heihe River: A case study of Pailugou catchment.
    2011, 30(01):  177-182. 
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    In mountain region of upper Heihe River, the characteristic of soil water regime is of unsaturated, and thus, to accurately estimate the values of its topsoil unsaturated hydraulic conductivity (K10) is essential for ecohydrological modeling. Taking the Pailugou catchment in upper Heihe River as a case, its topsoil K10 values were measured, and simulated by the pedotransfer functions (PTFs) integrating with factors-soil mechanical composition, bulk density, and average particle size. The observedK10in forestland, grassland and bare land was 0.21±0.20, 0.20±0.16 and 0.93±0.63 cm·h-1, and its spatial variability coefficient was 0.95, 0.79 and 0.67, respectively. The simulatedK10 was sensitive to soil mechanical composition and bulk density, resulting in different estimation effect of different PTFs estimation models for different sites. Therefore, the PTFs estimation models should be tested before application. The PTFs estimation models of K10 for Pailugou catchment were fitted, with R2=0.76 and the sample geometric mean error ratio GMER=1.77, indicating that they were practically applicable in the study region.
    Dynamic assessment of urban ecosystem health in Hefei City based on emergy analysis.
    2011, 30(01):  183-188. 
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    With the increasing prominence of urbanization and urban environmental issues, urban ecosystem health assessment has become a hot topic in ecology. In this paper, four elements including vigor, organizational structure, resilience, and function maintenance were collected to construct an emergy indicator, the improved emergy urban ecosystem health index (IEUEHI), to assess urban ecosystem health. This index was used for assessing the ecosystem health of Hefei City, and compared with other six cities in China, i.e., Tianjin, Wuhu, Shanghai, Ningbo, Baotou, and Fuzhou. The results showed that the health level of Hefei decreased continuously from 2004 to 2008. The IEUEHI of the City was higher than that of Shanghai, Ningbo, Baotou, and Tianjin, but lower than that of Fuzhou and Wuhu. Therefore, it would be necessary to improve the health level of Hefei by decreasing the environmental threat and improving the city’s organizational structure and resilience and services.
    Effects of seasonal change on dispersal of Quercus aliena seeds.
    2011, 30(01):  189-192. 
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    Seasonality is a key environmental factor affecting the seed dispersal by rodents. From September to November (autumn) in 2008 and from March to April (spring) in 2009, investigations were made on the dispersal of Quercus aliena seeds by forest rats in the Foping National Nature Reserve on south slope of Qinling Mountains, and the results were compared with the prediction from mast seeding hypothesis. It was shown that 1) the seed dispersal speed was significantly faster in spring than in autumn, and the mean dispersal distance (eating distance and hoarding distance) was also farther in spring than in autumn, being contrary with the prediction from mast seeding hypothesis, and 2) the hoarding proportion was significantly lower in spring than in autumn, which was consistent with the prediction from mast seeding hypothesis.