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    20 August 2009, Volume 20 Issue 08
    Articles
    Characteristics of soil respiration in artificial restoration process of subalpine coniferous forest in eastern Qinghai-Tibet plateau.
    2009, 20(08):  1783-1790. 
    Asbtract ( 1926 )   PDF (799KB) ( 650 )  
    By the method of infrared CO2 determination in closed dynamic chamber system, the soil respiration in natural spruce forest, and 22-, 35-and 65-year old spruce plantations in eastern Qinghai-Tibet plateau was measured in situ, and the soil heterotrophic and autotrophic respiration was differentiated by entrenchment. In the four spruce forests, soil respiration rate had a significant positive exponential correlation with the soil temperature at depth 5 cm, but less correlation with the soil moisture content at the same depth. The annual soil respiration flux was 79208-107020 g C·m-2·a-1, and decreased in the order of natural spruce forest>22-year old spruce plantation>65-year old spruce plantation>35-year old spruce plantation. The annual soil autotrophic and heterotrophic respiration fluxes were 25336〖KG-*2〗-〖KG-*7〗35705 g C·m-2·a-1 and 53869〖KG-*2〗-〖KG-*7〗70382 g C·m-2·a-1, respectively, and had the same variation trend as the annual soil respiration flux. The Q10 value of soil respiration in 22-, 35-, and 65-year old spruce plantations and in natural spruce forest in growth season (from Nov. 2007 to Mar. 2008) and non-growth season (from Apr. 2008 to Oct. 2008) were 459, 654, 477, and 318, and 417, 466, 311, and 274, respectively. Except that in 22-year old spruce plantation, the Q10 value was decreased with increasing restoration year, and was obviously higher in non-growth season than in growth season.
    Carbon and nitrogen storages and allocation in tree layers of Fraxinus mandshurica and Larix gmelinii plantations.
    2009, 20(08):  1791-1796. 
    Asbtract ( 2036 )   PDF (437KB) ( 677 )  
    By the methods of wood analysis and sequential soil core, the biomass and productivity of the tree layers in 20-year old Fraxiuns mandshurica and Larix gmelinii plantations, as well as the carbon (C) and nitrogen (N) storages in the above- and below-ground organs of the stands, were estimated. The biomass of F. mandshurica and L. gmelinii was 681510 g·m-2 and 929595 g·m-2, in which, stem occupied 5732% and 5801%, and fine roots occupied 267% and 180%, respectively. The annual productivity of F. mandshurica and L. gmelinii was 161816 and 210245 g·m-2·a-1, in which, stem accounted for 3934% and 4670%, and fine roots accounted for 1206% and 525%, respectively. The C content in the organs of F. mandshurica was lower than that of L. gmelinii, while the N content was in adverse. The C storage of F. mandshurica was lower than that of L. gmelinii, while the N storage had no significant difference between the two tree species. The biomass, productivity, and C and N storages of aboveground organs were lower for F. mandshurica than for L. gmelinii, indicating the higher construction efficiency of the aboveground part of L. gmelinii. Due to the significant differences in the C and N contents between tree species and between the organs of same tree species, the measurement should be made on different tree species and different organs to have an accurate estimation of forest C and N storages.
    Influence of soil moisture, nitrogen and phosphorus contents on Bauhinia faberi seedlings growth characteristics in arid valley of Minjiang River.
    2009, 20(08):  1797-1804. 
    Asbtract ( 1972 )   PDF (806KB) ( 694 )  
    To study the influence of resources thresholds on plant growth is a major theme in restoration ecology. Based on the simulation of the natural thresholds of soil moisture, nitrogen (N), and phosphorus (P) under drought condition in the arid valley of Mingjiang River, a full factorial experiment was designed to study the dynamics of Bauhinia faberi seedlings survival rate, growth, biomass production, and resources use efficiency across one growth season. High soil moisture (40% field water capacity), high soil P (24 mg P·kg-1), and low N (100 mg N·kg-1) increased the seedlings survival rate, and promoted the seedlings growth, biomass production, and water use efficiency. There was a significant coupling effect between soil N and P, but the interactions between soil moisture and soil N and P were not obvious. High N (240 mg N·kg-1) restrained the seedlings growth markedly, while high P mitigated the negative effects of high N via increasing root area, root length, and root mass to promote the seedlings N and P uptake. The N and P use efficiency across one growth season kept steady, and had significant positive correlation with root/shoot mass ratio. The combination of high soil moisture, low N, and high P promoted the seedlings growth effectively, while that of low soil moisture, low P, and high N inhibited the seedlings growth markedly.
    Characteristics of coarse woody debris |in Huzhong area of Great Xing’an Mountains.
    2009, 20(08):  1805-1810. 
    Asbtract ( 1976 )   PDF (429KB) ( 678 )  
    An investigation was made on the coarse woody debris (CWD) in burned f
    orestlands in Huzhong area of Great Xing’an Mountains. The loading capacity of
    CWD in the burned forestlands was 249〖KG-*2〗-〖KG-*7〗1810 m3·hm-2
    , among which, snag and log occupied 243%〖KG-*2〗-〖KG-*7〗859% and 14.
    0%〖KG-*2〗-〖KG-*7〗757%, being 60〖KG-*2〗-〖KG-*7〗939 m3·hm-2
     and 153〖KG-*2〗-〖KG-*7〗1384 m3·hm-2, respectively. Significan
    t differences were observed among burned forestlands and among years. The predom
    inant DBH class of snag and log was 25〖KG-*2〗-〖KG-*7〗20 c
    m and 15〖KG-*2〗-〖KG-*7〗15 m, and the height of most snags and logs was
    25〖KG-*2〗-〖KG-*7〗15 m and 5〖KG-*2〗-〖KG-*7〗20 cm, respectively. The loa
    ding capacity of CWD had no obvious change with the recovery of forest vegetatio
    n. The characteristics of CWD had a close relationship with pre-fire forest sta
    nd conditions and burn intensity.
    Spatial structure of Quercus mongolica forest in Beijing Songshan Mountain Nature Reserve.
    2009, 20(08):  1811-1816. 
    Asbtract ( 1914 )   PDF (406KB) ( 996 )  
    Based on the survey data of a 06 hm2 plot in Songshan Mountain Nature Reserve, and by using the uniform angle index, neighborhood comparison and mingling degree, this paper  analyzed the spatial structural characteristics of Quercus mongolica forest in the Reserve. There were 10 populations in the tree layer of the forest, among which, Q. mongolica had the obvious advantage in population density and basal area, being the dominant and constructive species of the tree layer. The average mingling degree of the forest was 0299, suggesting the low mingling degree of stands. The dominant species was mainly none- or less-mixed, while the accompanying species were generally well-mixed. In the spatial structural units, Q. mongolica and Pinus tabulaeformis populations were mainly of dominant, sub-dominant, and intermediate trees, accounting for 68% and 58% of the total plants of the populations, respectively, while the advantages of other populations were not obvious, being mostly of suppressed trees. The spatial pattern of the stands was of aggregative distribution, but the aggregation degree was not high and the aggregation scale was not large.
    Photosynthetic characters of Quercus acutissima from different provenances under effects of salt stress.
    2009, 20(08):  1817-1824. 
    Asbtract ( 1995 )   PDF (779KB) ( 699 )  
    The photosynthetic characteristics of Quercus acutissima from Feixian, Chuzhou and Wanyuan provenances were investigated under NaCl stress at 5 concentrations. For the three provenances, their leaf chlorophyll a (Chl a) and chlorophyll b (Chl b) contents and net photosynthetic rate (Pn) decreased with increasing salt stress, among which, the maximal decrement of Chl a content was 215%〖KG-*2〗-〖KG-*7〗361% for Feixian provenance, and 35%〖KG-*2〗-〖KG-*7〗198% for Wanyuan provenance. The diurnal variation of Pn in control groups had a single peak, and no midday photosynthetic depression was observed. Under high salt stress, all the provenances presented midday photosynthetic depression. Path analysis indicated that the major factors affecting Pn were vapor pressure deficit (VPD) and leaf temperature (Tl), while the minor factors were stomatal conductance (Gs), intercellular CO2 concentration (Ci), and photosynthetically active radiation (PARi). In the control groups, the photosynthetic characteristics mainly depended on the climate factors of provenance location. Based on the variations of leaf chlorophyll contents and Pn among the provenances under different salt stress, Wanyuan provenance had the highest salt tolerance, followed by Chuzhou provenance, and Feixian provenance.
    Effects of environmental stress on seedlings root growth and nodulation of leguminous shrubs in the dry valley of |Minjiang River.
    2009, 20(08):  1825-1831. 
    Asbtract ( 2107 )   PDF (402KB) ( 710 )  
    A field investigation was made to understand the seedlings root nodula
    tion, biomass accumulation, root length, and fine root percentage of Sophora d
    avidii, Indigofera lenticellata and Campylotropis polyantha along an alt
    itudinal gradient on two contrasting sloped hills (north Zongqu and south Jingzh
    oushan) in the dry valley of  Minjiang River. In the meantime, a greenhouse
     experiment was conducted to study the adaptation responses of 2 month-old
    S. davidii and C. polyantha seedlings root nodulation  to different soil moisture regimes (80%, 60%, 40%, and 20% WHC). For the thr
    ee test shrub species, fewer nodules were observed at lower altitude (1600〖KG-*
    2〗-〖KG-*7〗1950 m) areas, the nodule number per plant of S. davidii, I. lent
    icellata, and C. polyantha being 01±01, 09±05, and 57±19, a
    nd the non-nodulation plant accounting for 651%, 123% and 176%, respectiv
    ely. The nodule number of the three species increased with increasing altitude,
    and correlated positively with root length and fine root percentage. However, th
    ere were no significant differences in the plant growth and biomass at different
     altitudes. When the soil moisture content was lower than
     60% WHC, the nodule number and the  fresh and dry mass of both S. davidi
    i and C. polyantha decreased markedly, and at 20% WHC, no nodule and only
    98±36 nodules were observed for S. davidii and C. polyantha, respec
    tively, indicating that in this dry valley, the root nodulation capability of en
    demic leguminous shrubs was very low. Comparing with S. davidii, C. polyan
    tha had higher root nodulation capability and drought-resistance. Prior
     to introducing these shrub species in forestation practices, to keep the soil m
    oisture content higher than 40% WHC was recommended for relatively efficient bio
    logical nitrogen fixation.
    Relationships between coefficient of variation of diameter and height and competition index of main coniferous trees in Changbai Mountains.
    2009, 20(08):  1832-1837. 
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    A total of 1139 trees from 8 clear-cut stands dominated by fir, spruce, and pine in the Changbai Mountains were selected to study the relationships between the coefficient of variation of diameter and height and the competition index of the three main coniferous tree species in the Mountains. For the test tree species, the variation of height vs. diameter class was relatively small, while the variations of diameter and height vs. age class were larger, with the largest coefficient of variation of diameter vs. age class. The traditional height-diameter models could better reflect the real growth of trees, whereas the diameter-age or height-age models were not good enough. Competition was the main factor inducing the variations of tree diameter and height, suggesting that incorporating the competition index to the traditional models of tree growth and height could improve the model accuracy significantly.
    Effects of nitrogen addition on grassland species diversity and productivity in Keerqin Sandy Land.
    2009, 20(08):  1838-1844. 
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    Species diversity and productivity are the important indices of the structure and functioning of ecosystems. With Keerqin sandy grassland as test object, this paper studied its species composition, species diversity, and productivity under effects of different level nitrogen (N) addition. Nitrogen addition altered the species composition and the dominant species in the community, increased the vegetation height and coverage, and decreased vegetation light penetration. With the increase of N addition, both the species richness and the diversity decreased. Nitrogen addition increased the aboveground biomass significantly (P<001). There was a significant positive relationship between species richness and vegetation light penetration (P<001), and a significant negative relationship between species richness and vegetation coverage (P<001). It was suggested that  nitrogen deposition and artificial nitrogen addition would affect the species composition, species diversity, and productivity of sandy grassland ecosystem.
    Effects of simulated soil warming on the growth and physiological characters of Deyeuxia angustifolia.
    2009, 20(08):  1845-1851. 
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    By using improved heating cables, a field experiment was conducted to
    study the effects of 1 ℃〖KG-*2〗-〖KG-*7〗30 ℃ soil warming on the growth and phys
    iological characters of Deyeuxia angustifolia. Soil warming obviously promoted t
    he growth of D. angustifolia. Under flooded condition, the plant height incr
    eased by 182%, leaf area increased by 3732%, root volume increased by 2467
    %, total root absorbing area increased by 60%, and tillers number increased by 2
    581%; under un-flooded condition, the plant height increased by 1209%, leaf
     area increased by 329%, root volume increased by 3626%, total root absorbin
    g area increased by 3747%, an
    d tillers number increased by 3277%. The responses of D. angustifolia phys
    iolog
    ical indices to soil warming were more obvious under flooded than under un-floo
    d
    ed condition. Under flooded condition, the total chlorophyll content and root so
    luble protein content increased by 98% and 2388%, while the leaf soluble pro
    te
    in and soluble carbon contents and root soluble carbon content decreased by 25
    0
    2%, 2292%, and 3523%, respectively. 1 ℃〖KG-*2〗-〖KG-*7〗30 ℃ soil warming pro
    moted the growth of
    D. angustifolia, but the responses of its physiological characters to the so
    il warming varied with water conditions.
    Effects of doubled CO2 concentration on Erigeron breviscapus growth and its active constituent accumulation.
    2009, 20(08):  1852-1856. 
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    With medicinal plant Erigeron breviscapus as test material, its biomass and the contents and yields of scutellarin and caffeate were monitored under doubled (800±100) μmol·mol-1 and natural (400±25) μmol·mol-1 CO2 concentration. Comparing with those under natural CO2 concentration, the biomass of E. breviscapus under doubled CO2 concentration increased by 22%, the contents of scutellarin and caffeate increased by 23% and 26%, and the yields of these two constituents increased by 376% and 453%, respectively. Different organs had different responses in their biomass and active constituent contents to the elevated CO2 concentration. Under doubled CO2 concentration, the plant N content decreased by 472% and was negatively correlated with active constituent contents, being accorded well to the C/N balance hypothesis, and the biomass was positively correlated with the active constituent contents while no trade-off was observed between plant growth and secondary metabolism, suggesting that rational application of CO2 could improve the yield and quality of E. breviscapus.
    Species diversity of AMF community colonized in herbages roots in calcareous soil and purple soil.
    2009, 20(08):  1857-1862. 
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    A total of 17 herbages belonging to 12 families were selected as the host plants of arbuscular mycorrhizal fungi (AMF). They were grown on calcareous soil and purple soil, respectively, and sampled on the 120th day after seedling emergence. The DNA of AMF in the herbages roots was extracted by CTAB method, the partial rDNA sequence encoding ribosomal 28S big unit was amplified with special primers U1/U2 for fungi, and the PCR products were analyzed with PAGE silver staining method. In calcareous soil, 29 AMF bands were found in the roots of the 17 host plant species, and each host plant was colonized by 829 AMF bands; while in purple soil, only twenty-four AMF bands were found, with 947 bands in each host plant. All the AMF bands included unique bands and common bands. Cluster analysis showed that the AMF colonization in host plant roots was family-specific, and affected by soil factors. The feasibility of applying AMF in ecological restoration of limestone area was also discussed in this paper.
    Allelopathy of Phragmites australis on Spartina alterniflora under different salinity.
    2009, 20(08):  1863-1867. 
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    Using Phragmites australis litter as test material;two kinds of its mother liquid;i.e.;water extract and decomposed products;were obtained by the methods of solution extraction and anaerobic decomposition. The two liquids with concentration 100% and 25% were used to treat the seeds and seedlings of Spartina alterniflora and the endemic beneficial fungi (Mortierella sp.) of S. alterniflora under 5‰ and 10‰ salinity;aimed to study the effects of different salinity on the germination and growth of S. alterniflora and the growth of the fungi. Salt stress promoted the seed germination and young root growth of Spartina alterniflora as well as the growth of Mortierella sp. significantly (P<005). The water extracts promoted the germination and growth of Spartina alterniflora and the growth of Mortierella sp. when the salinity was 10‰;but the promotion effect disappeared when the salinity was reduced to 5‰. The decomposed products of Phragmites australis restrained the germination of Spartina alterniflora significantly (P<005) when the salinity was 5‰;but promoted the growth of Mortierella sp. significantly (P<005) when the salinity was 10‰. Under the two salinities;the decomposed products restrained the growth of Spartina alterniflora seedlings and young roots significantly (P<005).
    Effects of population distribution pattern and irrigation schedule on radiation utilization in winter wheat farmland.
    2009, 20(08):  1868-1875. 
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    A field experiment was conducted in 2006〖KG-*2〗-〖KG-*7〗2008 to study the effects of different population distribution pattern and irrigation schedule on the radiation utilization in a winter wheat farmland at the same population density (204×106 plant·hm-2). Four population distribution patterns were designed, i.e., row spacing (cm) × plant spacing (cm) 7×7 (A), 14×3.5 (B), 24.5×2 (C), and 49×1 (D), and each pattern had four irrigation schedules, i.e., no-irrigation, irrigation at jointing stage, irrigation at jointing and heading stages, and irrigation at jointing, heading and filling stages. The irrigation amount was 060 m3 each time. In the patterns A and B, the tiller number and leaf area index (LAI) were significantly higher than those in C and D (P<005). With the increase of row spacing, the photosynthetically active radiation (PAR) transmittance ratio increased gradually, while the PAR capture ratio had a decreasing trend. Increasing irrigation times increased the tiller number and LAI, but decreased the transmittance ratio of PAR, resulting in a significant increase of PAR capture ratio (P<005). The PAR capture ratio in the crop canopy was higher in upper layers, compared with that in lower layers. Relatively uniform population distribution and irrigation increased the PAR capture ratio in the upper 40 cm canopy layers significantly. The radiation use efficiency (RUE) decreased with increasing row spacing, with the two year's average total RUE in A, B, C, and D being 124%, 127%, 121% and 106%, respectively, and that in B was 521% and 1956% higher than that in C and D, respectively, with the difference being significant. It was suggested that relatively uniform population distribution improved the winter wheat population structure and PAR capture, being beneficial to the fully use of radiation, and irrigation also had positive effects on the population structure, being helpful to the increase of crop RUE.
    Effects of water-nitrogen interaction on soil water utilization by wheat and fructan content in wheat stem.
    2009, 20(08):  1876-1882. 
    Asbtract ( 2030 )   PDF (478KB) ( 698 )  
    A field experiment was conducted to study the effects of water-nitrogen interaction on the flag leaf photosynthetic rate, penult stem fructan content, fertilizer N use efficiency, and soil water use efficiency of strong gluten wheat variety ‘Jimai 20’. Three N application levels (N0, 0 kg·hm-2; N1, 180 kg·hm-2; and N2, 240 kg·hm-2) and four irrigation schedules (W0, no irrigation; W1, irrigation before sowing and at jointing and flowering stages; W2, irrigation before sowing, before wintering, and at jointing and flowering stages; W3, irrigation before sowing, before wintering, and at jointing, flowering, and grain-filling stages) were designed. The irrigation amount was 60 mm each time. Among the N treatments, treatment N1 had a higher flag leaf net photosynthetic rate and penult stem fructan content, and the highest grain yield, apparent N use efficiency, agronomic N use efficiency, and water use efficiency. Treatment N2 had a higher penult stem fructan content than treatments N0 and N1. No N application and applying excessive N did not benefit the increase of grain yield, fertilizer N use efficiency, and water use efficiency. Treatment W1 promoted the fructan accumulation in penult stem and accelerated the translocation of the accumulated fructan to grain, being beneficial to the increase of grain yield. Treatment N1W1 had the highest grain yield, and higher fertilizer N use efficiency and water use efficiency. Excessive irrigation and N application increased the flag leaf net photosynthetic rate and penult stem fructan content, but decreased the fertilizer N use efficiency and water use efficiency, with no significant effects on grain yield.
    Timing- and concentration effect of belowground treatment with jasmonic acid on maize seedlings chemical defense response.
    2009, 20(08):  1883-1890. 
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    Biochemical and gene expression analysis methods were adopted to investigate the defensive substances and the defense-related genes expression in the roots and leaves of maize (Zea mays L.) cultivar Gaoyou 115 after underground treatment with 10, 50, 100 and 200 μmol·L-1 of jasmonic acid (JA) for 3〖KG-*2〗-〖KG-*7〗48 h, aimed to explore the timing- and concentration effect of belowground treatment with JA on the chemical defense response of maize. The chemical defense response of both treated roots and non-treated leaves of Gaoyou 115 was related to the time span of JA treatment and the concentration of JA. After treated with JA for 3〖KG-*2〗-〖KG-*7〗12 h, the gene expression of 〖STBX〗Bx9, PAL, PR-2a〖STBZ〗, MPI and FPS in treated roots was directly induced, resulting in an increase of DIMBOA content and a decrease of total phenol content, with the strongest induction effect detected at 100 μmol·L-1 of JA, followed by at 50 μmol·L-1, and at 10 μmol·L-1. The induction effect weakened with time. Underground treatment with JA indirectly affected the chemical defense response of non-treated leaves. After underground treatment with 50 μmol·L-1 of JA for 3 h, the gene expression of 〖STBX〗Bx9〖STBZ〗 and FPS in non-treated leaves was induced, which caused a consequent increase of leaf DIMBOA content. Within 6
    〖KG-*2〗-〖KG-*7〗24 h of JA treatment, the gene expression of 〖STBX〗Bx9, PAL, PR-1〖STBZ〗, MPI and TPS in leaves was enhanced, while the leaf DIMBOA and total phenol contents were declined. For most of the parameters measured, the direct induction effect on roots was much more significant and started earlier than the indirect induction effect on leaves, and an increasing trend was observed in the induction effect with increasing JA concentration.
    Effects of light quality on microtuber induction of Solanum tuberosum L.
    2009, 20(08):  1891-1895. 
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    With the detoxified test-tube seedlings of two Solanum tuberosum L. v
    arieties as test materials, this paper studied their development and microtuber
    induction under effects of different light quality (red, blue, and white lights)
    . Under red light, the seedlings leaf net photosynthetic rate, soluble sugar con
    tent, and biomass were the highest, and the leaf number was the greatest. Blue l
    ight increased the seedlings dry matter content and microtuber number, advanced
    the date of microtuber initiation, but inhibited seedlings height. Under white l
    ight, the seedlings had the lowest net photosynthetic rate and dry matter conten
    t. Different S. tuberosum varieties had definite differences in the demand o
    f light quality for their microtuber induction. Applying red light at seedlings
    development stage and supplying blue light at microtuber induction stage could g
    ain higher productivity.
    A near-infrared spectral index for estimating soil organic matter content.
    2009, 20(08):  1896-1904. 
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    Taking the air-dried samples of five soil types from middle and easte
    rn China as test materials, the correlations of their organic matter content wit
    h the spectral reflectance of near-infrared (1000〖KG-*2〗-〖KG-*7〗2500 nm), a
    nd with the ratio index (RI), difference index (DI), and normalized diff
    erence index (ND) of the first derivative values of the reflectance between
    two bands were studied. Based on this, the key spectral indices and the quantita
    tive models for estimating soil organic matter (SOM) content were developed. Aft
    er corrected with Multiplicative Scatter Correction (MSC) and Savitzky-Golay (S
    G) smoothing methods, the spectral reflectance of near-infrared had an obviousl
    y high correlation with SOM, compared with the original spectral reflectance, wh
    ile the corrected spectral indices of the first derivative values of the reflect
    ance between two bands took the intermediate position. The correlation of the sp
    ectral indices with SOM was in the order of was DI>RI>ND, regardless the c
    omposition of the original spectral reflectance or the first derivative spectra.
     The DI of the reflectance of near-infrared between 1883 and 2065 nm correc
    ted with MSC and SG smoothing methods [DI(CR1883, CR2065)]
     had the best linear correlations with SOM. The test of the moni
    toring model based on DI(CR1883, CR2065) with the independen
    t datasets of SOM showed that the R2 and RMSE validation values were 083
    7 and 406, respectively. Comparing with the results from the Partial Least Squ
    are (PLS) method, the monitoring model based on DI (CR1883, CR
    2065) was somewhat inferior. However, the DI (CR1883, CR2065
    ) only needed two reflectance bands, and the monitoring model was
     simpler, being able to provide more available information for developing portab
    le instruments, and a good spectral index for estimating SOM content.
    Effects of the grain size and thickness of dust deposits on soil water and salt movement in the hinterland of the Taklimakan Desert.
    2009, 20(08):  1905-1911. 
    Asbtract ( 1840 )   PDF (780KB) ( 624 )  
    By using mcirolysimeter, a laboratory simulation experiment was conducted to study the effects of the  grain size and thickness of dust deposits on the soil water evaporation and salt movement in the hinterland of the Taklimakan Desert. Under the same initial soil water content and deposition thickness condition, finer-textured (<0063 mm) deposits promoted soil water evaporation, deeper soil desiccation, and surface soil salt accumulation, while coarse-textured (0063〖KG-*2〗-〖KG-*7〗2 mm) deposits inhibited soil water evaporation and decreased deeper soil water loss and surface soil salt accumulation. The inhibition effect of  the grain size of dust deposits on soil water evaporation had an inflection point at the grain size 020 mm, i.e., increased with increasing grain size when the grain size was 0063〖KG-*2〗-〖KG-*7〗020 mm but decreased with increasing grain size when the grain size was > 020 mm. With the increasing thickness of dust deposits, its inhibition effect on soil water evaporation increased, and there existed a logarithmic relationship between the dust deposits thickness and water evaporation. Surface soil salt accumulation had a negative correlation with dust deposits thickness. In sum, the dust deposits in study area could affect the stability of arid desert ecosystem.
    Micro-scale soil characteristics in salinization area of Songnen plain.
    2009, 20(08):  1912-1917. 
    Asbtract ( 1816 )   PDF (2155KB) ( 667 )  
    The study by the methods of in situ observation and laboratory analysis showed t
    hat the micro-relief in salinization area of Songnen Plain area was composed of
     flat land, micro-slope land, depression margin, and depression. Isohum
    usols distributed in depression, while alkalic halosols distributed in depressio
    n margin, micro-slope land, and flat land. The exchangeable sodium percent (ESP
    )
     in alkalized layer (15〖KG-*2〗-〖KG-*7〗30 cm) of alkaline soil in flat land w
    as 60%, and the ma
    ximal ESP in surface soil layer in micro-slope land could reach to 75%. The alk
    a
    lized soil layer in depression margin was mainly at the depth of 10〖KG-*2〗-〖K
    G-*7〗30 cm, where
     the maximal ESP could reach to 30%〖KG-*2〗-〖KG-*7〗40%. Nearly no alkalized la
    yer was found in t
    he soil profile in depression. The soils developed on the four micro-relief uni
    t
    s had obvious differences in their water retention curves. The maximal saturatio
    n moisture content in the soils of micro-slope land was only 25%, while that of
     
    0〖KG-*2〗-〖KG-*7〗10 cm soil layer in depression reached to 45%. The freezing
    -thawing process in
     different micro-relief units differed markedly, with the maximal frozen depth
    i
    n micro-slope land and depression being 157  and 136 cm, respectively. The su
    r
    face soil moisture content in depression increased from 20% before freezing to 5
    0% during freezing period. Among the four micro-relief units, micro-slope land
     h
    ad the most obvious variation of surface soil salt content during freezing-thaw
    ing, with the increment after thawing being as high as 80%.
    Soil condensation water in different habitats in Horqin sandy land: An experimental study.
    2009, 20(08):  1918-1924. 
    Asbtract ( 2085 )   PDF (904KB) ( 627 )  
    Weighing method was adopted to study the formation time and the amount
     of soil condensation water in four habitats (mobile sandy land, fixed sandy lan
    d, farmland, and Mongolian pine forest land) in Horqin Sandy Land in August 2007
    . The soil condensation water began to form at 20:00〖KG-*2〗-〖KG-*7〗22:00, in
    creased gradually at 22:00〖KG-*2〗-〖KG-*7〗4:00, and began to evaporate after
    4:00. In the four habitats, soil c
    ondensation water was mainly formed in 0〖KG-*2〗-〖KG-*7〗9 cm layer, and the a
    mount was the greatest in 0〖KG-*2〗-〖KG-*7〗3 cm layer, accounting for 40% of
    the total. The soil condensation water also formed in 9〖KG-*2〗-〖KG-*7〗30 cm layer, but in ver
    y small amount. There was a greater difference in the mean daily amount of soil condensation wate
    r in 0〖KG-*2〗-〖KG-*7〗3 cm layer in the four habitats, with the sequence of f
    ixed sandy land > mobile sandy land > farmland > Mongolian pine forest land, which indicated that
     the habitat with better vegetation condition was not benefit the formation of s
    oil condensation water. The mean daily amount of soil condensation water in 0〖KG-*2〗-〖KG-*7〗3
    0 cm layer was 0172 mm in fixed sandy land, 0128 mm in Mongolian pine forest
     land, 0120 mm in mobile sandy land, and 0110 mm in farmland.
    Ecological effect of road network in the typical area of Yunnan Province based on integration of landscape pattern and process.
    2009, 20(08):  1925-1931. 
    Asbtract ( 1830 )   PDF (816KB) ( 663 )  
    By using the quantitative index of ‘probability of connectivity’, this paper analyzed the effects of road network on the landscape pattern, ecological process, and landscape function in the typical areas of Yunnan Province. Road network accelerated landscape fragmentation, and changed the structure, number, and distribution pattern of ecological process dispersal paths, with the effects increased with increasing dispersal ability. The road network generally reduced the landscape function in maintaining ecological process connectivity by >10% and the patch function by >40%, and the effect also increased with increasing dispersal ability.
    Ecological land use in three towns of eastern Beijing: A case study based on landscape security pattern analysis.
    2009, 20(08):  1932-1939. 
    Asbtract ( 2032 )   PDF (1244KB) ( 1108 )  
    With the well-developed theory and methodology of landscape security pattern, and by the analysis of natural, biological, and cultural processes, it’s possible to judge and plan the landscape security pattern of definite ecological process, i.e., to maintain the minimum ecological land use of this ecological process both in pattern and in area, which is of strategic significance. From the aspects of land coverage and spatial quality, this paper defined the ecological land use as the ecosystem (land unit) and its spatial position that have important significance in safeguarding critical ecological processes and providing critical ecosystem services. Taking three towns in eastern Beijing as an example, the ecological land use based on storm water management and biological conservation was analyzed. In the study area, the ecological land use at low, medium, and high security levels occupied 204%, 311%, and 486% of the total, respectively, indicating that the landscape security pattern approach based on critical ecological processes was an effective tool in the quantitative study of ecological land use, having important reference value for urban and land planning.
    Spatiotemporal dynamics and related affecting factors of summer algal blooms in Xiangxi Bay of Three Gorges Reservoir.
    2009, 20(08):  1940-1946. 
    Asbtract ( 1880 )   PDF (574KB) ( 726 )  
    In June-August 2008, the cyanobacterial bloom and chlorophycean bloom broke out
     one after the other in the Xiangxi Bay of Three Gorges Reservoir. Based on the
    weekly monitoring in summer in the Bay, and by using cluster analysis a
    nd discriminant analysis, the spatiotemporal dynamics and related affecting fact
    ors of the two blooms were studied. Each of the blooms could be divided into non
    -bloom group, transitional group, and bloom group. The two blooms had different
    uptake levels of dissolved Si (DSi), NO3--N+NO2--N, and PO43-
    -P. Cyanobacterial bloom had lower DSi concentration and lower TN/TP, DSi/TN an
    d DSi/TP ratios than chlorophycean bloom. The discriminant factors of cyanobacte
    rial bloom were Chl a, TN and PO43--P, while those of chlorophycean blo
    om were Chl a and DSi. Better discriminant results were obtained when dividing e
    ach bloom into non-bloom group and bloom group. The critical value of Chl a for
     cyanobacterial bloom and chlorophycean bloom was 40 and 20 μg·
    L-1, respectively.
    Effects of artificial seawater with different N/P ratio on early development of Laminaria japonica embryo spore.
    2009, 20(08):  1947-1951. 
    Asbtract ( 2032 )   PDF (354KB) ( 780 )  
    The embryo spores of Laminaria japonica were cultured in artificial se
    awater with different N/P ratio to observe their early development. 80 percent o
    f the spores cultivated in whole-ingredient artificial seawater developed norma
    lly, but the time of spore germination and gametophyte formation was lagged sign
    ificantly  and the amount of female gametes was significantly hig
    her than that of male gametes (P<0001), as compared to the control cultiva
    ted in natural seawater. Artificial seawater with different N/P ratio showed dif
    ferent effects on the spore germination rate. The artificial seawater with N/P>
    15 decreased the spore germination rate, while that without N or P inhibited the
     spore germination significantly (P<0001). It was concluded that
    L. japonica spores could develop normally in artificial seawater, but their
    germination rate was affected by the seawater N/P. The deficiency of N or P in a
    rtificial seawater would lag the time of gametophyte formation and affect the di
    fferentiation ratio of female-male gametes.
    Individual fecundity of Culter alburnus in Xujiahe Reservoir of China.
    2009, 20(08):  1952-1957. 
    Asbtract ( 1847 )   PDF (748KB) ( 647 )  
    In April-June 2008, the matured female Culter alburnus specimens were collected from the Xujiahe Reservoir of China. Their ages were identified by the scales, and their body length, body mass, gonad mass, and other morphological indices were measured. Counted with gravimetric method, the individual absolute fecundity was obtained, and used for calculating the relative fecundity per centimetre, relative fecundity per gram, maturity, relative fatness, and other indices. Based on these measurements and calculations, the relationships between the individual fecundity and the morphological indices of C. alburnus in the Reservoir were studied. The ages of the specimens ranged from 2+ to 5+ years old, and the individual absolute fecundity and relative fecundity per centimetre were exponentially correlated with body length and body mass, and linearly correlated with age. No significant correlations were observed between the relative fecundity per gram and these morphological indices. Multi-regressive analyses showed that the individual absolute fecundity was significantly correlated with body mass and gonad mass, the relative fecundity per centimetre was significantly correlated with gonad mass, relative fatness and maturity, while the relative fecundity per gram was only correlated with maturity.
    Seasonal distribution of macrozoobenthos and its relations to environmental factors in Oujiang River estuary sea area.
    2009, 20(08):  1958-1964. 
    Asbtract ( 1947 )   PDF (1340KB) ( 1070 )  
    To evaluate the seasonal distribution of macrozoobenthos and its relations to environmental factors in Oujiang River estuary and adjacent waters, two cruise surveys were conducted in May 2006 (spring) and January 2007 (winter). A total of 65 species were collected, among which, polychaeta and mollusk were the dominant groups,  Capitella capitata and Nassarius succinctus were the dominant species in spring and winter, respectively. The species number of macrozoobenthos was more in adjacent sea area than in estuary, and more in spring than in winter. The average biomass and density in the two seasons were 1966 g·m-2 and 131 ind·m-2, respectively. There was a significant difference in the macrozoobenthos density between the two seasons, while less difference was observed in the biomass. The Shannon-Weiner index had significant difference between the two seasons, while Pielou eveness index, Margalef abundance index, and Simpsom dominance index had not. Water temperature and phytoplankton were the key factors affecting the macrozoobenthic taxa in spring, and water total organic carbon and dissolve oxygen were the key affecting factors in winter.
    Effects of grassland restoration from cropland on soil macrofaunal community in Wuchuan County, Inner Mongolia.
    2009, 20(08):  1965-1972. 
    Asbtract ( 2039 )   PDF (321KB) ( 593 )  
    By the method of hand-sorting, and using the indices individual numbe
    r, group number, and biodiversity, the changes in the soil macrofaunal community
     under the grassland restoration from cropland in Wuchuan County, Inner Mongolia
     were investigated. A total of 1479 soil macrofauna belonging to 3 classes, 7 or
    ders and 41 families were captured. After the grassland restoration from croplan
    d, the group number, individual number, and biomass of soil macrofauna all had a
    n increasing trend, and the biodiversity of soil macrofaunal community reflected
     by DMa and DG increased significantly. However, due to the short term of crop
    land rehabilitation, the Shannon-Wiener index H′ and the Pielou evenness index
     E of the soil microfaunal community in grassland were not higher than those in
    cropland. Different soil macrofaunal groups had different responses to the grass
    land restoration from cropland. The preferable approaches for the grassland rest
    oration from cropland were planting Medicago sativa or planting Medicago s
    ativa+Artemisia sp.
    Electroantennogram responses of Maruca testulalis (Lepidoptera: Pyralidae) to plant volatiles and sex pheromone.
    2009, 20(08):  1973-1979. 
    Asbtract ( 2150 )   PDF (462KB) ( 829 )  
    By using cis-3-hexenyl acetate as standard chemical, the electroante
    nnogram (EAG) responses of Maruca testulalis (Lepidoptera, Pyralididae) to p
    lant volatiles and sex pheromone were investigated. Both the males and the femal
    es of M. testulalis showed strong EAG responses to the volatiles, but no sig
    nificant difference was observed under most test concentrations. Among the test
    nine plant volatiles, the males and females had greater difference in the shape
    of EAG response to trans-2-hexenal, and their maximum  EAG relative response to
     high concentration trans-2-hexenal was 250% and 260%, respectively. No obviou
    s EAG responses were observed to the cedrene and cedrol from cowpea Vigna unguic
    ulata floral. Both the male and the female moths showed clear EAG responses to s
    ex pheromone, and significant difference was detected between males and females.
     The maximum  EAG relative response of the males to (E10, E12)-16 CHO, a main co
    mponent of sex pheromone, was 250%, while that of the females was only 53%. The
    difference in the EAG responses between the males and females reflected the diff
    erence in the structure, function and behavior of the males and females olfacto
    ry system.
    Relationships among Cyrtotrachelus buqueti larval density and wormhole number and bamboo shoot damage degree.
    2009, 20(08):  1980-1985. 
    Asbtract ( 2372 )   PDF (248KB) ( 722 )  
    In August of 2007 and 2008, a field investigation was made to study the relationships among Cyrtotrachelus buqueti larval density and wormhole number and bamboo shoot damage degree in Sichuan Province. The three pairs of variables, i.e., C. buqueti larval density and wormhole number, C. buqueti larval density and bamboo shoot damage degree, and C. buqueti wormhole number and bamboo shoot damage degree, fitted cubic equations well, with the correlation coefficients at P=0001. Based on these mathematical models, the forecast tables for C. buqueti larval density and bamboo shoot damage degree were established, and the thresholds of C. buqueti larval density and wormhole number were 013 and 040 individual per bamboo, respectively.
    Insect community structure and its stability in a Zanthoxylum bungeanum garden with different planting pattern.
    2009, 20(08):  1986-1991. 
    Asbtract ( 2234 )   PDF (397KB) ( 892 )  
    An investigation was made on the insect community composition and stru
    cture in a Zanthoxylum bungeanum garden with corn-soybean-Z. bungeanum
     intercropping, soybean-Z. bungeanum intercropping, corn-Z. bungeanum
    intercropping, and only Z. bungeanum planting in Zhaotong City of Yunnan Pro
    vince, and the community character index and principal component analysis were u
    sed to study the characters and stability of the insect community. A total of 32
    6 insect species were recorded. In intercropped plots, the abundance, diversity,
     and evenness index of insect community were higher while the dominance index
    was lower, compared with those in mono-cultured Z. bungeanum plot. The dive
    rsity index of insect community decreased in the order of corn-soybean-Z. bu
    ngeanum intercropping > soybean-Z. bungeanum intercropping > corn-Z. b
    ungeanum intercropping > only Z. bungeanum planting, and the insect commun
    ity in corn-soybean-Z. bungeanum intercropping plot was relatively stable.
    Relationships between mound size and captured ergate amount of Solenopsis invicta.
    2009, 20(08):  1992-1997. 
    Asbtract ( 2060 )   PDF (420KB) ( 755 )  
    By the method of bait trapping, this paper studied the relationships b
    etween mound size (mound volume and mound surface base area) and captured ergate
     amount of Solenopsis invicta in wasteland and greenbelt. In wasteland, with
     the
     increase of mound size, the amount of captured S. invicta ergates increased
     rap
    idly at first, slowed down then, and kept stable at last. When the mound volume
    and surface base area were 11634 cm3 and 1308 cm2 respectively, the captured
     ergate amount reached the maximum, being 291 individuals per trap. Similar patt
    erns were observed in greenbelt. The increase of captured S. invicta ergate
    amou
    nt slowed down rapidly when the mound volume was larger than 18089 cm3, and re
    ached
    the maximum (232 individual per trap) when the mound volume was 25974 cm3. The
     We
    ibull equation could better describe the relationships between the mound volume
    and mound surface base area and the captured ergate amount of S. invicta.
    Suitable habitat of Therioaphis trifolii population on arable lands of Southern Ningxia based on GIS.
    2009, 20(08):  1998-2004. 
    Asbtract ( 1881 )   PDF (570KB) ( 647 )  
    Based on GIS techniques, the interpolation maps of Therioaphis trifolii popu
    lation on the arable lands in Yuanzhou District of Guyuan City in differen
    t periods were overlapped with the ecological regionalization map and digital al
    titude map, aimed to analyze the relations of T. trifolii population density
     with its ecological environment and geographical distribution. In the study are
    a, the occurrence and distribution of T. trifolii had close relations with c
    limate, geomorphology, and altitude. The suitable habitat of T. trifolii in
    the District was located in the semi-arid plain area and semi-arid holly area
    at the altitude 1440〖KG-*2〗-〖KG-*7〗2000 m, while the most possible occurrenc
    e area was the semi-arid plain at the altitude 1600〖KG-*2〗-〖KG-*7〗1800 m. B
    y combining the suitable habitat with the interpolation maps of T. trifolii
    population in different periods, the spatial dynamics of T. trifolii populati
    on in variety of ecological areas could be analyzed quantitatively.
    Oviposition timing and community structure of Ficus curtipes fig wasps.
    2009, 20(08):  2005-2011. 
    Asbtract ( 1994 )   PDF (1076KB) ( 834 )  
    Through the behavioral observation of Ficus curtipes fig wasps and
     the counting of various kinds of flowerets in F. curtipes figs, the oviposi
    tion tim
    ing and community structure of 12 F. curtipes fig wasp species were studied.
     Bes
    ides the agaonid wasp Eupristina sp., the two non-agaonid wasps Diaziella
     yangi and Lipothymus sp. could enter into F. curtipes figs and ovipos
    it. The other nin
    e non-agaonid fig wasps (Walkerella sp., Micranisa sp., Sycophilomorp
    ha sp., Philotrypesis sp., Sycosapter sp., Sycobia sp., Ficomila
     sp., Ormyrus sp. and Sycophila sp.) oviposited outside the figs. In
    the fig wasp community, Eupristina sp. was the dominant species, accounting
    for 6211% of the total, D. yangi and Lipothymus sp. accounted for 27
    19% and 471%, respectively, while the other nine non-agaonid fig wasp species
     only occupied 599%. The non-agaonid fig wasps produced their progeny through
     the reproduction strategies of oviposition timing and diet allocation of female
     flowerets, so as to sustain the fig-wasp mutualism. The individuals of non-ag
    aonid fig wasp progeny had significant negative correlati
    on with those of agaonid fig wasp progeny, but no correlation with F. curtipes
     seed production.
    Effects of microbial agent inoculation on bacterial community diversity in the process of pig manure composting.
    2009, 20(08):  2012-2018. 
    Asbtract ( 2334 )   PDF (503KB) ( 1205 )  
    PCR-DGGE method was adopted to study the effects of inoculating exogenous microbial agent on the bacterial community diversity in the process of fresh pig manure high-temperature aerobic composting. Exogenous microbial agent inoculation promoted the composting process, with the high-temperature period being advanced by 2 days than that of non-inoculation. DGGE pattern analysis showed that during composting, the dominant bacteria changed significantly, with the Shannon-Wiener index of bacterial community at different composting periods varied obviously. The sequencing of DGGE-distinguished bands showed that Clostridium stercorarium subsp. thermolacticum sp. was the dominant group in the whole composting process. Uncultured bacteria Bacillus coagulans sp. and Clostridium thermocellum sp. became the main groups on the 10th and 16th day after microbial agent inoculation, while uncultured Firmicutes sp. and delta proteobacterium became the dominant groups on the 5th and 16th days in the treatment non-inoculation, respectively. Un-dominant group Ureibacillus thermosphaericu sp. and uncultured  Silvimonas sp. appeared in the late period of well rotted composting, while uncultured soil bacteria mainly appeared in the initial and high-temperature periods. UPGMC cluster analysis showed that exogenous microbial agent inoculation obviously affected the bacterial community structure in different composting periods, and the main component analysis of DGGE patterns in composting process showed that the bacterial community was mainly affected by the exogenous microbial agent inoculation.
    Planning of monitoring points for agricultural products security based on integrated weighted clustering method.
    2009, 20(08):  2019-2024. 
    Asbtract ( 1743 )   PDF (235KB) ( 605 )  
    Integrated weighted clustering method was applied to pl
    an the monitoring points for agricultural products security. Definite amounts of
     key monitoring sampling points were mined out from enormous monitoring objects
    to make the fewer monitoring sampling points cover the product categories, yield
    s, and regions as more as possible. Among the 10172 agricultural products securi
    ty enterprises all over the China, 246% of them were selected. The tested cate
    gories, yields, and regions of agricultural safety products covered 3271%, 44
    29%, and 75% of the total, and their coverage increased by 280%, 1085%, 5
    56%, respectively, compared with that by using conventional monitoring and man
    agement methods, which suggested that it could be more effective to apply integr
    ated weighted clustering method in setting the monitoring points for agricultura
    l produc
    ts security.
    Promotion effects of microorganisms on phytoremediation of heavy metals-contaminated soil.
    2009, 20(08):  2025-2031. 
    Asbtract ( 2138 )   PDF (369KB) ( 1181 )  
    Taking Brassica juncea as a hyperaccumulator, a pot experiment was conducted to study the effects of Bacillusme gaterium-Bacillus mucilaginosus mixed agent and Aspergillus niger 30177 fermentation liquor on the phytoremediation of Cd, Pb, and Zn-contaminated soil. The B. gaterium-B. mucilaginosus mixed agent not only promoted the growth of B. juncea, but also increased the soil Cd, Pb, and Zn uptake by the hyperaccumulator, with the phytoremediation  efficiency enhanced greatly. The enrichment amount of Cd, Pb and Zn in B. juncea on the soil added with soluble Cd, Pb and Zn increased by 118, 154 and 085 folds, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 400, 064 and 065 folds, respectively, compared with the control. A. niger 30177 fermentation liquor increased the soil Cd, Pb, and Zn uptake by B. juncea. Comparing with the control, the enrichment amount of Cd, Pb and Zn in aboveground part of B. juncea on the soil added with soluble Cd, Pb and Zn increased by 8882%, 12904% and 1680%, while that on the soil added with Cd, Pb and Zn-contaminated sediment increased by 7895%, 11363% and 3385%, respectively. However, A. niger 30177 fermentation liquor decreased the B. juncea biomass greatly, having less effect in the enhancement of phytoremediation efficiency. The analysis of reversed-phase high performance liquid chromatography showed that the fermentation liquor of B. gaterium and B. mucilaginosus contained some organic acids such as oxalic acid and citric acid. These acids could dissolve the heavy metals to some degree, and accordingly, enhance the bioavailability of the metals.
    Effects of cadmium stress on fatty acid composition and lipid peroxidation of Malus hupehensis.
    2009, 20(08):  2032-2037. 
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    This paper studied the fatty acid composition, reactive oxygen species (ROS), lipoxygenase (LOX) activity, and malondialdehyde (MDA) content in the leaves and roots of Malus hupehensis seedlings under effects of cadmium (Cd) stress. Noticeable changes were observed in the kinds and relative contents of fatty acids after treated with CdCl2 for 7〖KG-*2〗-〖KG-*7〗12 hours. The relative contents of unsaturated fatty acids in leaves and roots reached the maximum after treated for 7 hours, being 8282% and 7243%, respectively. The kinds of fatty acids in leaves increased from 11 to 14 after treated for 12 hours, while those in roots increased from 4 to 6 after treated for 17 hours. The O2〖SX(B-*3〗-〖〗·〖SX)〗 generation rate and the H2O2 content reached the maximum after treated for 3 and 7 hours, respectively, and the MDA content and LOX activity increased with treating time. Cd stress altered the fatty acid composition of
    Malus hupehensis via the inducement of reactive oxygen species and lipoxygenase, and induced lipid peroxidation, which was caused by both ROS and LOX within the first 12 hours of CdCl2 treatment and mainly by the increase of LOX activity since then.
    Air negative ion concentration and its relationships with meteorological factors in greenbelts of Jiamusi, Heilongjiang Province
    2009, 20(08):  2038-2041. 
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    From March 2006 to February 2007, a synchronous observation was conducted on the air negative ion concentration and related meteorological factors in the greenbelts of Jiamusi, with their relationships studied. There was an obvious diurnal and monthly variation in the air negative ion concentration, being higher in early morning and midnight and lower in mid-day and late afternoon, with the minimum of 217 ions per cubic centimeter, and being the highest in summer and the lowest in winter, with the maximum (782 ions per cubic centimeter) in July and the minimum (283 ions per cubic centimeter) in December. The air negative ion concentration was significantly negatively correlated with air temperature, and positively correlated with air pressure and relative humidity.
    Evaluation of landscape connectivity based on least-cost model.
    2009, 20(08):  2042-2048. 
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    Landscape connectivity, as a dominant factor affecting species dispersal, reflects the degree to which the landscape facilitates or impedes organisms’ movement among resources patches. It is also an important indicator in sustainable land use and biological conservation. Least-cost model originates from graph theory, and integrates the detailed geographical information with organisms’ behavioral characteristics in the landscape. Through cost distance analysis, this model can describe the species connectivity in heterogeneous landscape intuitively and visually. Due to the simple algorithm performed in GIS packages and the demand of moderate data information, least-cost model has gained extensive attention in the evaluation of large-scale landscape connectivity. Based on the current studies of landscape connectivity, this paper elaborated the significance, principles, and operation processes of least-cost model in evaluating landscape connectivity, and discussed the existing problems of the model in its practical applications, which would benefit the further related studies and biodiversity conservation.