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    10 November 2012, Volume 31 Issue 11
    Articles
    Effects of forest soil fauna on early-stage litter decomposition and nutrient release.
    CUI Yang1,2,3, WANG Si-long1,2**, YU Xiao-jun2, YAN Shao-kui1,2
    2012, 31(11):  2709-2715. 
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    A field microcosm experiment was conducted to study the effects of soil fauna on the earlystage litter decomposition in an evergreen broadleaf forest and a Cunninghamia lanceolata plantation in Huitong of Hunan, South-central China. The taxonomic diversity and abundance of soil macrofauna in the litters and soils were obviously lower in 2 mm mesh nylon net than in 4 mm mesh nylon net. After the exclusion of soil macrofauna, the C, P, Ca, and Mg concentrations in the litters in evergreen broadleaf forest and the Mg concentration in the litters in C. lanceolata plantation increased significantly, while both the mass loss rate and the nutrient release rates of the litters decreased significantly. Soil macrofauna had different effects on the release rates of different nutrients in the litters, with larger effects on the release rates of the litter Ca and Mg in evergreen broadleaf forest and C. lanceolata plantation, lesser effects on the release rates of N and K in C. lanceolata plantation, and least effects on the release rate of P in evergreen broadleaf forest.
    Effects of closetonature transformation of degenerated larch (Larix gmelinii) plantation on soil microbes and soil nutrients.
    LIU Yan-bin1,2, WANG Qing-cheng3**, WANG Cheng-yi2, CUI Song2, MENG Kuan-hong2
    2012, 31(11):  2716-2722. 
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    The decline of the productivity and soil fertility of larch (Larix gmelinii) plantation is an urgently addressed issue in forestry production. Especially for the second generation larch plantation, whether its closetonature transformation can improve the soil fertility, soil microbial diversity, and soil nutrient contents is lacked of indepth study. In this paper, an investigation was made on the effects of closetonature transformation of the second generation larch plantation on the soil microbial diversity and structure as well as the soil nutrient contents within two years of the transformation. The results showed that there was a close correlation between gap size and soil microbial diversity. After the first year of transformation, the soil microbial diversity in small gaps (25 m2) had a significant increase, with the Shannon index, richness index, and evenness index being higher than those in large gaps (100 m2) and the control (no-thinning). In the second year of transformation, less difference was observed in the three indices among the three treatments. The Shannon index and richness index were higher in the first year than in the second year, while the evenness index was in adverse, suggesting that in the first year of transformation, soil microbial diversity was higher but in uneven distribution. The soil microbial genetic similarity in small gaps was similar to that in the control; while in large gaps, this similarity was significantly different from the other two treatments, because of the greater changes of microclimate conditions in large gaps resulting in an intense change in soil microbial diversity. In the first year of transformation, soil nutrient contents had a significant increase. The soil available P content in large gaps was increased by 80%, and that in small gaps was increased by 52%; soil available N content was also increased; while soil available K content had less increase. In the second year, soil nutrient contents were decreased, but the decrements differed between large gaps and small gaps. The soil available P content had a significant decrease in large gaps, but the soil nutrient contents had less decrease in small gaps. This study provided evidences for the feasibility and scientific implementation of closetonature forest management.
    Carbon density of  forest ecosystems in mountainous region of east Liaoning Province, Northeast China.
    TIAN Jie1,2, YU Da-pao1, ZHOU Li1, ZHOU Wang-ming1, JIA Juan1,2, LIU Jia-qing1,2, DAI Limin1**
    2012, 31(11):  2723-2729. 
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    Based on the forest inventory data in 2009 and plot survey, and using allometric equation and vegetation type method, this paper estimated the carbon density and carbon storage of different components of  forest ecosystems in mountainous region of east Liaoning. In this region, the forest ecosystem carbon density was 300.050 Mg·hm-2, with 63.237 Mg·hm-2 in arbor layer, 0.558 Mg·hm-2 in shrub layer, 0.274 Mg·hm-2 in herbaceous layer, 3.529 Mg·hm-2 in litter layer, and 232.452 Mg·hm-2 in soil profile. The carbon density of arbor layer increased with increasing stand age, while that of shrub layer was in adverse. No obvious patterns were observed in the carbon density in soil, herbaceous layer, and litter layer among different aged stand groups. Overall, the forest ecosystem carbon storage in the mountainous region of east Liaoning (with an area of 305.852×104 hm2) was 917.709 Tg C, of which, soil carbon storage (710.959 Tg C) was 3.44 times of biomass carbon storage (206.75 Tg C). Through the comparison of our results with previous studies, it was found that due to the underestimation of the carbon density of young forests, the forest inventory data greatly underestimated the carbon storage of arbor layer. Meanwhile, in previous studies, the use of a simple conversion factor overestimated the carbon density of understory vegetation, but greatly underestimated the carbon density of soil.
    Characteristics of carbon accumulation and allocation pattern in Mytilaria laosensis plantation.
    MING An-gang1,2, JIA Hong-yan1, TAO Yi1, LU Yi1, YU Hao-long1, LU Li-hua1, CAI Dao-xiong1, SHI Zuo-min2**
    2012, 31(11):  2730-2735. 
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    Based on the biomass survey, this paper studied the characteristics of carbon accumulation and allocation pattern of a 28yearold Mytilaria laosensis plantation ecosystem in southwest Guangxi of South China. The carbon content in different organs of M. laosensis was in the range of 522.8-560.2 g·kg-1, with the order of leaf (560.2 g·kg-1) > stem (542.8 g·kg-1) > root (530.9 g·kg-1) > bark (530.8 g·kg-1) > branch (522.8 g·kg-1). The soil carbon content was the highest in surface layer, and decreased with increasing depth. The carbon storage in tree layer was 147.90 t·hm-2, of which, stem accounted for 63.72% of the total. The total carbon storage of the M. laosensis plantation ecosystem was 285.36 t·hm-2, and the allocation of the carbon storage in different components was tree layer > soil layer > litter layer > shrub layer > herb layer, with the carbon storage in vegetable layer being 1.1 times of that in soil layer (0-100 cm). The annual net carbon storage of the tree layer was 6.87 t·hm-2·a-1, which was dominated by the aboveground part.
    Characteristics of water consumption by Robinia pseudoacacia forest on Loess Plateau of western Shanxi Province, China.
    GUO Bao-ni1, ZHANG Jian-jun1,2**, WANG Zhen3, RU Hao1, HUANG Ming1
    2012, 31(11):  2736-2741. 
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    By using thermal dissipation probe (TDP) technique, a field observation was conducted on the stem sap flow of Robinia pseudoacacia forest on Loess Plateau of western Shanxi Province in the growth season (April-October), 2011. Combining with the synchronically observed meteorological factors and by using corresponding empirical formula, the transpiration water consumption and atmospheric evaporation capacity of the forest were calculated, and the correlations of the stem sap flow velocity and atmospheric evaporation capacity were studied. In May and August, the stem sap flow velocity and atmospheric evaporation capacity of the forest had the similar diurnal variation patterns in sunny and rainy days, being obviously smaller at night than at daytime, but not obvious in cloudy days. In the growth season of R. pseudoacacia, the correlation between the sap flow velocity and atmospheric evaporation capacity was significant in June, July, and August, but insignificant in other months, presenting a symmetrical distribution. The mean monthly transpiration water consumption had a symmetrical distribution during the growth season, with the minimum in April and the maximum in July. The atmospheric evaporation capacity was the minimum in October and the maximum in June, and the potential maximum atmospheric evaporation capacity during the growth season was 4.45 times of that of the measured forest transpiration water consumption.  
    Effects of plant species and litter on soil organic carbon sequestration in converted croplands in a typical watershed in Three Gorges Reservoir area of China.
    TIAN Yao-wu1,2, HUANG Zhi-lin2**, XIAO Wen-fa2
    2012, 31(11):  2742-2747. 
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    In order to understand the effects of plant species and litter on the soil organic carbon sequestration and translocation in converted croplands in a typical watershed in Three Georges Reservoir area, a field experiment was conducted. Three treatments including C3 plant (A1) and C4 plant Rhizoma cyperi with litter removal (B0) versus with double litter input (B2) were installed in 2008, and soil and plant samples were collected in 2010, with the organic carbon concentration and δ13C value in soil profiles measured. A changed organic carbon concentration in the soil profiles was observed due to the land use change. After 2 years conversion, the organic carbon concentration in 0-30 cm soil layer in A1 had an increase of 58.4 g C·m-2(1.1%), that in B0 had a distinct increase of 303.3 g C·m-2(4.9%), while that in B2 was decreased by 79 g C·m-2(1.1%). Litter input had significant effects on the soil organic carbon density (P<0.05).
    Organic carbon mineralization in lime soils in Karst region of Guangxi, South China in response to exogenous organic substrate and calcium carbonate.
    GE Yun-hui1,2,3, SU Yi-rong1,2, ZOU Dong-sheng3, HU Le-ning1,2, FENG Shu-zhen1,2, XIAO Wei1,2, HE Xun-yang1,2**
    2012, 31(11):  2748-2754. 
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    To elucidate the effects of exogenous organic substrate and calcium carbonate on the organic carbon mineralization in lime soils and to deepen the understanding of the characteristics of soil organic carbon turnover, the terra fusca, rendzina, and zonal red soil were collected from the Karst region in Huanjiang of Guangxi, and a 100-day incubation experiment was conducted, with the fluxes of CO2 and 14C-CO2 from the soils determined. Three treatments were installed, i.e., no exogenous addition (CK), addition of 14Clabeled rice straw (S), and addition of 14Clabeled calcium carbonate (C). In treatments S and C, the mineralization of soil organic carbon was promoted obviously, and the priming effect of 14Clabeled rice straw and 14Clabeled calcium carbonate on the organic carbon mineralization in the terra fusca, rendzina, and zonal red soil after 100-day incubation was 28.7%, 46.2%, and 15.5%, and 127.0%, 175.3%, and 100.1%, respectively. In the apparent cumulative mineralization, the contribution rate of 14Clabeled calcium carbonate in the terra fusca, rendzina, and zonal red soil was 40.4%, 48.4%, and 19.6%, respectively. Soil type, exogenous additives, and their interaction had significant effects on the priming effect of the soil organic carbon mineralization, the contribution of the additives to the apparent cumulative mineralization, and the cumulative mineralization volume (or rate) (P<0.01). This study indicated that the addition of exogenous organic substrate and calcium carbonate altered the characteristics of soil organic carbon mineralization, and, as for the lime soils, the contribution of inorganic carbonate should be taken into consideration in the study of the mineralization and turnover of soil organic carbon and the assessment of their effects on atmosphere CO2.  
    Genetic diversity of Populus pruinosa populations in Xinjiang of China based on SSR analysis.
    ZHANG Ling1,2, JIAO Pei-pei1,3, LI Zhi-jun1,2**
    2012, 31(11):  2755-2761. 
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    One hundred and thrityfive samples of nine natural Populus pruinosa populations in Xinjiang Uygur Autonomous Region of Northwest China were taken, and twelve pairs of SSR primers were utilized to study the genetic diversity and genetic structure of these populations. A total of 136 alleles were detected, with a mean of 11 bands per primer. The mean percentage of the polymorphic loci of all the populations (P) was 97.2%, the mean Shannon’s information index (I) and Nei’s gene diversity (h) at population level were 1.185 and 0.541, and the observed heterozygosity and expected heterozygosity were 0.321 and 0.560, respectively. These data suggested that the genetic diversity of P. pruinosa was quite high. Among the nine populations, ZP population had the richest genetic diversity, while 14T population had the poorest one. The AMOVA analysis showed that the percentage variation among the populations was 12%, while the percentage variation within the populations was 88%, illustrating that the genetic differentiation of P. pruinosa was quite low. According to the genetic differentiation coefficient, the gene flow between the populations was 2.424. The average genetic distance of the 9 populations was 0.244, and the 14T population and XML population were the closest in genetic distance and the highest in genetic identity. Using unweighted pair group method arithmetic average (UPGMA), the 48T population, 14T population, MGT population, MY population, and SY population were clustered into one group, the AWT population and ALE population were clustered into another group, and the ZP population and XML population were clustered into two independent groups, respectively. The Mantel test also indicated that the genetic distances among the populations had no significant correlations with their geographic distances. In sum, the ZP population had the richest genetic diversity, and thus, should be given a high priority consideration in the P. pruinosa population’s in situ germplasm conservation.
    Ecological adaptability of Huyou planting in Quzhou, Zhejiang Province of East China.
    YU Li-ping1, LI Zheng-zhou2, JIN Zhi-feng3**, LI Ren-zhong3, HUANG Jing-feng4
    2012, 31(11):  2762-2766. 
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    Huyou (Citrus paradisi cv. Changshan Huyou) is a characteristic fruit of high quality and high yield with the origin region protection in Quzhou City. To study the suitability regionalization of Huyou planting is of importance to the development of regional agricultural economy. Based on the geographic data, soil data, and 1971-2008 meteorological data of Quzhou, this paper analyzed the relationships between Huyou yield and meteorological factors, established the comprehensive regionalization indices of Huyou planting, and constructed a regionalization assessment model of Huyou planting by using analytic hierarchy process. The results indicated that the suitable, sub-suitable, and unsuitable regions for Huyou planting in the City occupied 65.47%, 13.12%, and 21.41% of the totalevaluation area, respectively. This regionalization could provide a scientific basis for the layout optimization of cultivation and the structural regulation of improved varieties of Huyou in Quzhou.
    Effects of topographic factors on the plant species richness and distribution pattern of alpine meadow in source region of Lancang River, Southwest China. 
    ZHANG Chang-shun1, XIE Gao-di1**, BAO Wei-kai2, CHEN Long1,3, PEI Sha1, FAN Na1
    2012, 31(11):  2767-2774. 
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    adopted to explore the responses of plant species richness and distribution pattern of alpine meadow in this region to topographic factors (altitude, slope grade, slope aspect, and slope position) under high intensity human disturbances and climate change. A total of 150 plant species were recorded in 275 plots (1 m ×1 m) of 55 sampling sites, and the species number in the plots ranged from 3 to 27. Statistical analysis demonstrated that the plant species richness was highly significantly correlated to altitude and slope grade, but less correlated to slope aspect or slope position. The CCA axis 1 basically reflected the gradient variation of plant communities with slope grade, axis 2 reflected the gradient variation with slope position, whereas axis 3 reflected the combined effect of topographic factors. Under the high intensity human disturbances and climate change, the topographic factors affecting the plant species composition and structure of alpine meadow in this region ranked as slope grade > slope position > altitude > slope aspect, suggesting that slope grade was the major factor affecting the water and soil conditions of alpine meadow in the source region of Lancang River.
    Nitrogen and phosphorus contents of six herb species in riparian zone of Hunhe River,  Northeast China.
    YU Shuai1,2, CHEN Wei1**, HE Xing-yuan1, LIU Zhou-li1, HUANG Yan-qing1
    2012, 31(11):  2775-2780. 
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    In this paper, the root, stem, and leaf samples were collected from six herb species (Artemisia selengensis, Potentilla cryptotaeniae, Impatiens nolitangere, Artemisia capillaries, Bidens biternata, and Polygonum persicaria) in the riparian zone at the upstream of Hunhe River in July, August, and September, 2010, aimed to compare the total nitrogen (TN) and total phosphorus (TP) contents in the organs of these herb species. In the test organs, the TN and TP contents were 5.10-45.06 mg·g-1 and 1.60-18.01 mg·g-1, respectively, and the N/P ratio ranged from 0.92 to 6.14, with an average of 2.68. There existed significant differences in the N and P contents between different organs of the same or different herb species. Among the test five species, I. nolitangere had the highest TN and TP contents, being able to be selected as a candidate species used for the improvement of water quality in the riparian zone of Hunhe River.
    Characteristics and distribution causation of aquatic macrophytes in Guohe River of East China.
    QIN Hong-yan1, LI Jing-de1, ZOU Dong-sheng1, LI Feng2**
    2012, 31(11):  2781-2787. 
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    On the basis of field survey and laboratory measurement, and by using Two-Way Indicator Species Analysis (TWINSPAN) and CCA ordination, this paper studied the species composition and community type of aquatic macrophytes in the Guohe River of Huaihe River Basin, and approached the key environmental elements affecting the distribution of the macrophytes. A total of 27 aquatic macrophyte species belonging to 20 families and 23 genera were recorded, of which, submerged and emergent species were the dominant species, accounting for 74% of the total. The macrophytes could be classified into 8 community types, i.e., Form. Eleocharis congesta+ Scirpus trigueter, Form. S. trigueter + Alternanthera philoxeroides, Form. S. trigueter, Form. Ceratophyllum demersum, Form. A. philoxeroides, Form. Phragmites australis + A. philoxeroides, Form. Nymphoides peltatum, and Form. Trapa bispinosa +Nuphar pumilum. There existed greater variations in the environmental factors, especially the concentrations of NH4+-N, NO3--N, and total P in water body and the water depth, among the 8 community types. The CCA ordination showed that the physical and chemical characteristics of water body, such as the NO3--N, PO4- and total P concentrations, were the key factors determining the distribution of aquatic macrophytes in the Guohe River.  
    Impacts of future climate change on middle-season rice yield in Central China: A simulation study.
    WAN Su-qin1, LIU Zhi-xiong1**, LIU Min1, SHUAI Xi-qiang2, XIANG Hua1, DENG Ai-juan1
    2012, 31(11):  2788-2796. 
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    According to the scenarios A2 and B2 in IPCC Special Report on Emissions Scenarios (SRES), the climate change scenarios based on regional climate model PRECIS were combined with rice growth model ORYZA2000, and, on the basis of many years experimental data and of model suitability verification, the growth period and yield of middleseason rice in base period (1961-1990) and in 2011-2050 under scenarios A2 and B2 were simulated, aimed to analyze the impacts of future climate change on the growth and yield of middleseason rice in Central China. In the next 40 years, the growth period of middleseason rice in Central China would be shortened, with an average of 3.5 days under scenario A2 and of 1.3 days under scenario B2, as compared with that in 1961-1990. The areas where the growth period would be shortened by more than 4 days would be in west Hubei. Without considering the effect of CO2 fertilization, the yield of middleseason rice in Central China would be decreased in the next 40 years. Under scenario A2, the yield reduction of rainfed middleseason rice would be averagely 17.8%, and that of irrigated middleseason rice would be 14.2%; under scenario B2, the yield reduction of rainfed middleseason rice would be averagely 16.4%, and that of irrigated middleseason rice would be 12.7%. The more yield reduction under scenario A2 than under scenario B2 indicated that the greater the increment of air temperature, the greater the negative effect of the increment on middleseason rice. Under the same scenarios, the yield reduction of irrigated middleseason rice would be smaller than that of rainfed middleseason rice, indicating that irrigation could offset the adverse effect of rising temperature to some extent. Considering the effect of CO2 fertilization, the variation trend of the middleseason rice yield in Central China would be inconsistent in the next 40 years. Under scenario A2, the yield reduction of rainfed middle season rice would be averagely 4.3%, but  irrigated middle season rice yield would be increased by  4.3%; while under scenario B2, the yield  would be increased by 3.6% and 11.8%, respectively. As compared to without considering the effect of CO2 fertilization, under the consideration of the effect of CO2 fertilization, the yield reduction of rainfed middleseason rice under scenario A2 would be decreased while the yield of irrigated middle season rice under scenario A2 and that of rainfed middle-season rice and irrigated middle season rice under scenario B2 would be increased, but the yield increment would be smaller than the yield reduction under the same scenarios, which indicated that CO2 fertilization could increase the yield of middleseason rice to some extent, but be not enough to offset the adverse effects of rising temperature. Whether considering the effect of CO2 fertilization or not, and rain-fed or irrigated, the future climate change would increase the instability of middle-season rice yield, and thus, increase the risk of middleseason rice production in Central China. The stability of irrigated middle-season rice would be greater than that of rainfed rice, and the stability of rice yield with CO2 fertilization would be greater than that without CO2 fertilization. Therefore, irrigation and adequate CO2 fertilization would be the effective measures to improve the stability of middle-rice yield.
    Effects of phased drought and re-watering on the photosynthetic characteristics and grain yield of winter wheat.
    LIU Li-ping1,2, OUYANG Zhu1**, WU Lan-fang1, LI Fa-dong1, LIU Peng-fei1,2
    2012, 31(11):  2797-2803. 
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    A rainproof and water controlling experiment was conducted to study the effects of phased drought and re-watering on the photosynthetic characteristics and grain yield of winter wheat. Four treatments, i.e., 70%±5% soil moisture content from turning green to maturity (S0), 55%±5% soil moisture content from turning green to anthesis together with 70%±5% soil moisture content from anthesis to maturity (S1), 70%±5% soil moisture content from turning green to anthesis together with 55%±5% soil moisture content from anthesis to maturity (S2), and 55%±5% soil moisture content from turning green to maturity (S3), and two planting densities, i.e., 525 and 675 basic seedlings per square meter, were installed. In treatment S0, the flag leaf chlorophyll content, chlorophyll fluorescence parameters, and photosynthetic characteristic parameters and the grain yield were higher than those in other three treatments, and the photosynthetic characteristic parameters and grain yield were significantly higher than those in treatments S3 and S2. Though the photosynthetic characteristic parameters in treatment S1 increased to some extent, showing an overcompensation effect, the grain yield presented a slight decrease, as compared to that in treatment S0. The water use efficiency in treatments S1, S2, and S3 was 143.2%, 86.5%, and 97.3% of that in treatment S0, respectively. It was suggested that to maintain 55% moisture content in 0-40 cm soil layer from turning green to anthesis and maintain 70% moisture content in this soil layer from anthesis to maturity could be the optimal water management way for obtaining definite grain yield of winter wheat while high efficiently saving water. Due to the interaction between water and plant density on the grain yield of winter wheat, the optimal water management way suggested above and the plant density of 675 basic seedlings per square meter could be the optimum combination for winter wheat with the consideration of watersaving and highyielding.
    Effects of grafting on the growth, physiology, and biochemistry of eggplants under water stress.
    ZHOU Bao-li**, MENG Zhao-hua, LI Juan, CHEN Zhi-xia
    2012, 31(11):  2804-2809. 
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    Taking the wild eggplant (Solanum torvum) as rootstock and the cultivated eggplant (S. melongena) cultivar ‘Xi’anlvqie’ as scion, this paper studied the growth and the physiological and biochemical indices of grafted and self-rooted eggplants under water stress. Soil water stress severely restricted the growth of grafted and self-rooted eggplants. In treatment CK (80%-85% of soil water content), the growth of grafted and self-rooted eggplants had no obvious difference; while in the treatments of light (50%-55%) and severe (35%-40%) water stress, the difference was quite significant. Under water stress, as compared with those of selfrooted eggplants, the plant height and stem diameter, the fresh weight and dry weight of aboveground parts and roots, and the leaf relative water content and chlorophyll content of grafted eggplants all had a significant increase, while the leaf relative conductivity and MDA had a significant decrease. Grafting increased the plant leaf soluble sugar and proline contents significantly. With the increase and the extending of water stress, the differences in the leaf SOD and POD activities between grafted and self-rooted eggplants became larger, reached a significant level. It was suggested that grafting could promote the eggplant growth and adjust the plant osmotic regulation substances contents and antioxidant enzymes activities to maintain the normal function of plant physiological metabolism and bring about stronger adaptability to moderate drought.
    Effects of applying phosphorus and fungicide on the growth and physiological characteristics of Flaveria bidentis.
    CHEN Dong-qing, ZHANG Rui, HUANGFU Chao-he**, JIANG Na, TU Chen-yang, YANG Dian-lin
    2012, 31(11):  2810-2816. 
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    A pot experiment was conducted to investigate the roles of soil fungi on the invasion of Flaveria bidentis and to reveal the soil microbial mechanisms involved during this invasion. In the experiment, five levels of KH2PO4 (50 mg·kg-1 of CaSO4, P0; control, no P addition, P1; 20 mg·kg-1 of P, P2; 40 mg·kg-1 of P, P3; and 80 mg·kg-1 of P, P4) were applied, combining with applying fungicide benonyl to suppress soil fungi, aimed to understand the effects of applying P and benonyl on the invasion of F. bidentis. Applying fungicide had significant effects in decreasing the infection rate of AM fungi on F. bidentis, inhibiting the plant photosynthesis, and reducing the plant biomass, soluble sugar content, and protective enzymes (SOD, POD, and CAT) activities, while applying higher levels of P (P3 and P4) under the application of benonyl increased the plant total P content, but had minor effects on  plant total N, soluble protein, and chlorophyll contents. The nutritional status of F. bidentis and the activity of AM fungi on F. bidentis varied with P addition levels. In treatments P0, P1, and P2, the contribution rate of soil fungi to the N and P uptake by F. bidentis was positive, but the opposite result was obtained in treatments P3 and P4. It was suggested that there was a significant interaction between soil fungi and P application levels, and the growth of F. bidentis could be promoted by soil fungi, especially by AM fungi, combining with appropriate P fertilization.
    Effects of spraying calcium on the inflorescence stem quality and leaf photosynthesis of herbaceous peony (Paeonia lactiflora Pall.).
    LI Cheng-zhong1,2, TAO Jun1**, SUN Yan2, KONG Fen1, GENG Qing-ping1, DU Bei1
    2012, 31(11):  2817-2822. 
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    Taking 5-year old herbaceous peony (Paeonia lactiflora Pall.) as test material, a pot experiment was conducted to study the effects of spraying calcium (4%, w/v) on the inflorescence stem quality and leaf photosynthetic characteristics of the plant. Under the spraying of calcium, the mechanical strength of the inflorescence stem increased significantly by 24.3%, and the cellulose, semicellulose, lignin, and pectin contents in the inflorescence stem all increased significantly, among which, the cellulose content reached 456.54 μg·g-1 and enhanced by 28.5%, as compared with the control. The leaf net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and water use efficiency also increased, with the Pn up to 17.07 μmol·m-2·s-1 28 days after calcium application and enhanced by 29.6%, and the Gs, Tr and WUE enhanced by 55%, 20%, and 7.6%, respectively, as compared with the control. In addition, spraying calcium led to an increase of the maximum net photosynthetic rate (Pmax) and the light saturation point, which were up to 20.71 μmol·m-2·s-1 and 902.5 μmol·m-2·s-1 and enhanced by 24.6% and 7.5%, respectively, but led to a significant decrease of light compensation point, which was 7.27 μmol·m-2·s-1 and decreased by 34.5%.
    Physiological responses of Hypnum plumaeforme to different inorganic nitrogen forms.
    TAN Ying1, SHU Ting2, ZHAO Yan-jun2, LIU Bin-yang2, LIU Wei-qiu2**
    2012, 31(11):  2823-2827. 
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    This paper studied the physiological responses of Hypnum plumaeforme to two kinds of inorganic nitrogen, i.e., KNO3 and NH4NO3. The addition of KNO3 or NH4NO3 within the range of 20-60 kg N·hm-2·a-1 caused the starch and soluble sugar contents in H. plumaeforme decreased, while the total nitrogen, soluble protein, free amino acid, arginine, histidine, and proline contents increased. With the addition of KNO3 or NH4NO3, the total nitrogen content in H. plumaeforme had significant negative correlations with the starch and soluble sugar contents, suggesting the competition for carbon skeleton between the H. plumaeforme’s nitrogen and carbon assimilation. The coefficients of the negative correlations under NH4NO3 addition were far higher than those under KNO3 addition, suggesting that the decrease in the starch and soluble sugar contents under KNO3 addition was also related to the decrease of net photosynthesis rate and carbohydrate production, besides the carbon skeleton consumption during nitrogen assimilation. As compared with KNO3 addition, NH4NO3 addition resulted in a greater increase of arginine but a less increase of proline in H. plumaeforme, indicating that H. plumaeforme possessed a welldeveloped NH4+ detoxification system.
    Cadmium accumulation and its effects on the photosynthesis of Thalassia hemprichii.
    FENG Shao-hui1,2,3, HUANG Xiao-ping1**, JIANG Zhi-jian1,3
    2012, 31(11):  2828-2833. 
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    By the methods of sequential extraction and chlorophyll fluorescence, a laboratory experiment with no sediments was conducted to study the cadmium (Cd) accumulation in different organs of tropical seagrass Thalassia hemprichii and the effects of Cd on the photosynthesis of the seagrass. The Cd accumulation in T. hemprichii organs was in the order of leaf > root > rhizome. In all treatments, the Cd in the T. hemprichii organs was dominated by the 1 mol·L-1 NaCl-, 2% HAc-, and 0.6 mol·L-1 HClextractable Cd, occupying 80%-99% of the total Cd, indicating that the less active and weakly migrated forms were the main forms of Cd in T. hemprichii. Under the exposure of increasing concentration Cd, the proportion of 0.6 mol·L-1 HClextractable Cd in different organs of T. hemprichii decreased by 7%-24%, while the proportion of 1 mol·L-1 NaCl and 2% HAcextractable Cd increased by 2%-24%. On the other hand, the 80% ethanol and dH2Oextractable Cd, the high active Cd forms, decreased in T. hemprichii leaf but increased in root and rhizome. These results suggested that T. hemprichii could weaken the toxicity of Cd by changing the proportion of different Cd forms in cells and/or organs. Under the exposure of high concentration Cd, the effective quantum yield (ΔF/Fm′) and the chlorophyll a, chlorophyll b and total chlorophyll contents declined significantly, suggesting that the photosynthesis of T. hemprichii was seriously impaired. It seemed that the protective mechanisms evolved by T. hemprichii could play an important role in Cd detoxification when exposed to relatively low concentration Cd, but became restricted under higher Cd stress.
    Chlorophyll content and its distribution in the sediments of Daya Bay, South China in winter.
    YIN Gui-jin1,2, YAN Yan1**
    2012, 31(11):  2834-2840. 
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    In February (winter), 2012, an investigation was conducted on the chlorophyll a (Chl-a) and phaeopigments (Pha-a) contents and their distribution in the sediments of Daya Bay, and the relationships of the Chl-a in surface layer of the sediments with the environmental variables (water depth, temperature, transparency, granularity, nutrients, and TOC) were analyzed. The Chl-a and Pha-a in the sediments had the same source. The contents of Chl-a and Pha-a decreased significantly with increasing sediment depth, and there were several leaps in the vertical distribution of Chl-a and Pha-a, which might reflect the effects of bioturbation and environmental change. The Chl-a and Pha-a contents in the surface layer (0-1 cm) of the sediments varied from 0.98 to 1.55 μg·g-1 and from 3.97 to 6.65 μg·g-1, respectively, with the mean contents being 1.24 μg·g-1 for Chl-a and 5.55 μg·g-1 for Pha-a. The most important factor affecting the Chl-a content was the particle size of the sediments. The high proportion of sand in the sediments would provide more living space for microphytobenthos, but this type of sediments would save less Pha-a. The comparison between the Chl-a content in the sediments and in the upper water as well as in the other marine areas showed that the ratio of the Chl-a content in the sediments and in the upper water ranged from 50.28% to 150.79%, suggesting that the primary productivity in the sediments of coastal area should not be ignored.
    Spatial niches of Caragana korshinskii seed pests in desert steppe landscape of Ningxia, Northwest China.
    ZHANG Da-zhi**
    2012, 31(11):  2841-2847. 
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    Caragana korshinskii is a major sandfixating plant species in arid and semiarid regions of China, while Kytorhinus immixtus, Etiella zinckenella, and Bruchophagus neocaraganae are the dominant seed pests of C.korshinskii. Selecting the C.korshinskii shrubberies in three habitat types of manually fixed sandy land, mobile sandy land, and sandy loam hilly land in desert steppe of Ningxia as test objects, an investigation was made on the spatial distribution characteristics of the three dominant seed pests of C.korshinskii in the patches of different areas, with the relationships between the seed pests spatial niches and the patch area analyzed. In the habitat of sandy loam hilly land, the vertical distribution of the pests in C.korshinskii shrubbery was in the order of canopy layer (38.9%) > middle layer (33.9%) > bottom layer (27.2%), and the horizontal distribution was in the sequence of western sector (31.0%) > northern sector (29.3%) > southern sector (21.7%) > eastern sector (18.1%) of the shrubbery. K. immixtus and B. neocaraganae mainly distributed in the canopy layer, while E. zinckenella mainly distributed in the middle layer. In most cases, one pod was only occupied by K. immixtus, B. neocaraganae, or E. zinckenella. It was quite rare that two or three species of the seed pests lived in the same pods. In these cases, one individual occupied a bean. E. zinckenella had the highest vertical and horizontal niche breadths (0.977 and 0.917), followed by B. neocaraganae (0.959 and 0.829), and by K. immixtus (0.773 and 0.690, respectively). No significant differences in the niche breadths of the three seed pests were observed among the three habitats, and there was no significant correlation between the niche breadth and patch area.
    Artemia- population in Haixin Division of Chengkou saltworks, Shandong Province of East China: Ecological investigation.
    WANG Jing1, SUI Li-ying1**, HE Hua1, LIU Wen-ling1, GAO De-tao2, ZHANG Rong-qi2, SUN Chuan-wei2
    2012, 31(11):  2848-2854. 
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    Artemia- plays an important role in the biological management of saltworks ecosystem. To approach the effects of the ecological environment of saltworks on the dynamics of Artemia population, six salt ponds with different salinity in Haixin Division of Chengkou saltworks, Shandong Province were chosen, and the related ecological factors were investigated by means of monthly sampling, onsite measuring, and laboratory analysis. It was observed that the brine temperature varied with seasons, and slightly increased with increasing salinity. The brine pH slightly decreased with increasing salinity. In general, the chlorophyll a content in the brine was lower (<0.3 ug·L-1), as compared to that in normal seawater. The total nitrogen and phosphorous concentrations in the brine increased with increasing salinity, and the nitrogen was the restrictive element for phytoplankton growth in lower salinity ponds whilst the phosphorous became the limiting factor in higher salinity ponds. The density of Artemia population varied with the brine temperature and salinity, being higher at higher temperature (from June to August) and lower salinity (7-12 °Bé). The analysis of the sex ratio of female and male Artemia indicated that in the Chengkou saltworks, there existed mixed Artemia populations of both parthenogenetic and bisexual. The density of the populations was affected by salinity and temperature, i.e., parthenogenetic population was predominantly existed in lower salinity salt ponds and in spring and summer, whilst the bisexual population became majority in higher salinity salt ponds and in autumn.
    Vertical distribution and dispersal of adult Sitodiplosis mosellana (Gehin) in wheat field.
    MIAO Jin1, WU Yu-qing1**, GONG Zhong-jun1, ZHU Kun2, DUAN Yun1, JIANG Yue-li1, LI Tong1 
    2012, 31(11):  2855-2858. 
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    By using yellow sticky traps, an investigation was made on the population density of adult Sitodiplosis mosellana in vertical direction and the sex ratio of the adults in a wheat field. The activities of the adult S. mosellana in the wheat field were mainly at 0-40 cm  above the ground, and the population density decreased with increasing height. The sex ratio of the adults varied widely in different eclosion periods, with a higher percentage of males in the early period but nearly 100% of females in the late period. In vertical direction, the percentage of the females increased with increasing height. Weather factors played an important role in the dispersal of adult S. mosellana.  
    Potential of bioenergy production from garden wastes in West Lake scenic spots of Hangzhou, China.
    SHI Yan1, ZHENG Nan1, TANG Yu-li2, FAN Li-kun2, GUO Ke-jian1, FAN Xing1, GE Ying1, CHANG Jie1**
    2012, 31(11):  2859-2864. 
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    The development of bioenergy may provide a solution to achieve the reduction targets for scenic spot emissions. This paper provides a synthesis of questionnaire survey and experimental data to assess the potential of garden waste biomass for renewable energy production in West Lake of Hangzhou. Our results showed that the waste dry biomass from greenspace reaches 4.60±3.12 t·hm-2·a-1. The garden waste dry biomass from greenspace in the road area was 5.96 t·hm-2·a-1 which was higher than the other area. The main species of the garden wastes were Cinnamomum camphora, Osmanthus fragrans and Rhododendron simsii. The total amount of dry biomass from scenic wastes was estimated at 3402 t·a-1. The total potential biofuel produced as scenic waste biomass was estimated at 6.3×1010 kJ·a-1, which accounts for 40% of the energy consumption for the West Lake. The wood pellets production bioenergy system was the best way for the garden waste biofinery. The emission reduction of using garden waste for energy production to alternative fossil fuels would be 4177 t CO2 per year. The use of garden wastes in scenic area for energy production could be a winwin approach for the reduction of environment stress and the increase in the energy supply.  
    Phytoplankton community structure and water quality assessment of Changzhao Reservoir, Zhejiang of East China.
    LIU Jin-dian1,2, GU Zhi-min1,2**, YANY Yuan-jie1,2, ZHANG Yu-ming3
    2012, 31(11):  2865-2871. 
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    An investigation was conducted on the community structure of phytoplankton in Changzhao Reservoir of Zhejiang Province in May, August, and November, 2010, and the diversity of the community species was analyzed by using Shannon diversity index, Simpson diversity index, Margalef diversity index, and Pielou evenness index. Meanwhile, the water quality of the Reservoir was evaluated based on the physicalchemical parameters. The identified phytoplankton species in the Reservoir belonged to 26 species or genera of 6 phyta, consisting of Cyanophyta (4 species or genera), Cryptophyta (1 genus), Pyrrophyta (1 genus), Bacillariophyta (9 species or genera), Chlorophyta (10 species or genera), and Xanthophyta (1 genus). The abundance of the phytoplankton ranged from 5.73×105 to 7.73×105 ind·L-1, with an average of (6.71±0.81)×105 ind·L-1, and the biomass ranged from 0.73 to 1.03 mg·L-1, with an average of (0.83±0.12) mg·L-1. At all sampling sites, the species of Cyanophyta, Bacillariophyta, and Chlorophyta had high abundance in each season, whereas the species of Bacillariophyta, Chlorophyta, and Cyanophyta had the highest abundance in spring, summer, and autumn, respectively. Overall, the abundance and biomass of the phytoplankton community were higher at the inlet but lower at the outlet of the Reservoir. The diversity of the phytoplankton community in the Reservoir was lower, and the water was heavily polluted, with high concentrations of nitrogen and phosphorus and middlerich nutrition grade of eutrophication.
    Health assessment of fastgrowing and highyielding Cunninghamia lanceolata plantations in Huangfengqiao Forest Farm of Hunan Province, Southcentral China.
    CHEN Chun-lin, ZHOU Guo-ying**, WU Yi, LI Hong-jun, MA Lin
    2012, 31(11):  2872-2876. 
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    Based on the principles of scientificity, holism, representativeness, and operability, thirteen evaluation indices were selected from the secondclass forest resources inventory data, and a health assessment index system of fastgrowing and highyielding Cunninghamia lanceolata plantations was constructed. In the meantime, the standard for classifying the C. lanceolata plantations health grade was ascertained, and the health status of the C. lanceolata plantations in 817 subcompartments of Huangfengqiao Forest Farm in Hunan Province was evaluated. Among the subcompartments, those in unhealthy, subhealthy, and healthy occupied 24.7%, 57.3%, and 18.0% of total, respectively. Young plantations had a poorer health condition, middleaged plantations were better, overmature plantations were generally in subhealthy, while nearmature and matured plantations were comparatively healthy. These results could provide reference for the health management of the C. lanceolata plantations in the Farm.
    Integrative assessment of ecological risk in coastal cities of Liaoning Province, Northeast China.
    DU Yu-fei1, LI Xiao-yu1**, GAO Bin2, HU Hai-de3, HE Xing-yuan1
    2012, 31(11):  2877-2883. 
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    Based on the remote sensing images of 1992 and 2007, and by using GIS spatial analysis technique, a model about the land use change and population increase pressure in the coastal cities of Liaoning was built to comprehensively assess the ecological risk of these cities. The results showed that in 1992-2007, the ecological risk presented a pattern of gradual increasing from inland to coastal area, i.e., from north to south, with higher risk in flat, trafficdeveloped, and densely populated areas but lower risk in high elevation and less human disturbance mountainous and hilly regions. The transfer matrix of the ecological risk indicated that in the 15 years from 1992 to 2007, the conversion between different ecological risk levels was mainly from low-grade to highgrade risk, the ecological pressure of the cities became increasingly larger, and both the level and the scope of the ecological risk were increasing.
    Contribution rates of climate change and human activity on the runoff in upper and middle reaches of Heihe River basin.
    HE Xu-qiang, ZHANG Bo**, SUN Li-wei, JIN Sheng-li, ZHAO Yi-fei, AN Mei-ling
    2012, 31(11):  2884-2890. 
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    Based on the 1960-2008 meteorological and hydrological data in the upper and middle reaches of Heihe River basin, and by the methods of linear regression, nonparametric MannKendall test, accumulative anomaly, annual accumulation, and change rate of accumulation slope, this paper analyzed the variations and trends of the runoff and climate in this region, and calculated the contribution rates of climate change and human activity on the runoff. In the upper reaches of Heihe River basin, the annual runoff, precipitation, and evaporation presented an overall increasing trend, with a significant increase of the annual runoff and evaporation. In the midstream, the annual runoff and evaporation exhibited a decreasing trend while the annual precipitation was in adverse, but the trends were not obvious. The abrupt change year of the runoff in the upper and middle reaches was 1979 and 1984, respectively. According to the abrupt change year of runoff, the time series were divided into upstream (1960-1979 and 1980-2008) and midstream (1960-1984 and 1985-2008), and the linear equations of the accumulated runoff, accumulative precipitation, and accumulative evaporation and the time series were obtained. In the upstream, climate change played dominant role, human activity had lesser effects, and their contribution rates to the increase of runoff were 59.71% and 40.29%, respectively. In the midstream, the effects of climate change on runoff were lesser, while human activity played dominant role, with their contribution rates to the decrease of runoff being 25.23% and 74.77%, respectively. This study could provide a guide for the future water resources development and utilization in Heihe River basin.  
    Ecological safety assessment of Dagu estuary wetland in Jiaozhou Bay of Shandong Province, East China based on landscape pattern.
    YU Rong-rong1, XIE Wen-xia1**, ZHAO Quan-sheng1, XU Zhen2, LIU Wen-long1
    2012, 31(11):  2891-2899. 
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    By using Landsat TM as the main data source, and with the help of GIS and ENVI 4.4 software, the spatial information of the natural wetland, constructed wetland, and non-wetland in the Dagu estuary of Jiaozhou Bay in 1986, 2002, and 2010 was extracted, and, based on the principles and methods of landscape indices, the ecological safety index was constructed, aimed to quantitatively analyze the dynamic changes of the landscape in the study area, and elucidate the area’s ecological safety status and related driving mechanisms under the changes of landscape pattern. From 1986 to 2010, due to the natural and anthropogenic double interferences, the land area of Dagu estuary was diminishing. The amount of patches increased, dominant landscape disappeared, and landscape tended to be complicated, fragmentized, and separated. The interference of human activities on the landscape became more and more obvious. There was a negative correlation between the landscape interference index and ecological safety index. The loss degree of each landscape increased, while the ecological safety index decreased, with the landscape of river and reed wetland having the largest deterioration degree. The areabased landscape ecological safety was in the order of nonwetland > constructed wetland > natural wetland. To some extent, the newly established forest plantations and the newly integrated Shaohai East Lake artificial wetland park offset the ecological loss in the study area, alleviated the conflict between the area’s ecological conservation and economic growth, and developed a new way to protect the wetland.
    Evaluation of ecosystem services value of aquatic germplasm resources conservation zone: A case study in Beibu Gulf of South China sea.
    XU Shan-nan, CHEN Zuo-zhi**, YU Jie, LI Chun-hou
    2012, 31(11):  2900-2906. 
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    Aquatic germplasm resources conservation zone plays vital roles in protecting aquatic biodiversity, aquatic germplasm resources and their habitats, having great value of ecosystem services. Taking the National Aquatic Germplasm Resources Conservation Zone for Paragyrops edita and Penaeus penicillatus in the Beibu Gulf of South China as a case, and based on field investigation, an evaluation was made on the total value of ecosystem services (VES) of this conservation zone by the methods of market value, shadow project, and travel cost, etc. The total VES of the Conservation Zone in 2008 amounted to 836087.52×104 ¥, with an average VES per unit area of 7321.26×104 ¥·hm-2. Among all the service function types, the value of provision service was 585078.42×104 ¥, occupying 69.98% of the total VES, and those of regulation service and culture service were 182680.00×104 ¥ and 68329.10×104 ¥, occupying 21.85% and 8.17% of the total, respectively. The large value of the ecosystem services indicated the vital role of the Conservation Zone in maintaining the biological production of Beibu Gulf and in promoting the sustainable economic development of the surrounding areas of the Gulf. Some suggestions were made on the construction of the criteria of ecosystem services value evaluation, strengthening of related basic theoretical research, and acceleration of the establishment of ecological compensation mechanisms for aquatic germplasm resources conservation zone.
    Coniferous forest ecosystem services value in Jiangxi Province of China: A dynamic analysis.
    ZENG Wei1, XIONG Cai-yun1, XIAO Fu-ming1**, YU lin1, LIU Xiang-feng2
    2012, 31(11):  2907-2913. 
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    According to the Specifications for Assessment of Forest Ecosystem Services in China (LY/T 1721-2008), an analysis was made on the coniferous forest ecosystem services value in Jiangxi Province in the ninth (1996-2000) and the tenth (2001-2005) fiveyear periods. From the ninth to the tenth five-year period, the total value of the coniferous forest ecosystem services in the Province had a slow increase, from 367 billion yuan per year to 377 billion yuan per year and with an annual increment of 2.92%, but the service value per year per hectare decreased from 70.4 thousand yuan to 69.3 thousand yuan, with a decrement of 1.55%. The permutation orders of the coniferous forest ecosystem’s six services values during the two fiveyear periods were the same, and the first two (the values of water conservation and of carbon fixation and oxygen release) occupied 81.6% of the total. Among the services values, water conservation value was the largest, making important sense to the Jiangxi Province with severe soil and water loss, whereas the carbon fixation and oxygen release values as well as their proportions in total value had the most rapid increase. In the coniferous forests in Jiangxi, young and middleaged forests were the main parts, with a great potential of carbon sequestration.  
    Dynamic changes of wetland landscape pattern in Tianjin, North China.
    LIU Dong-yun1,2**, HUANG Xiao-lei2, DU Lin-fang2, FENG Zhong-ke2
    2012, 31(11):  2914-2920. 
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    By using the TM images of Tianjin in 1999, 2003, and 2007 as the data source to acquire the wetland transition matrixes, and with CA-Markov model, this paper simulated the dynamic changes of wetland landscape pattern in Tianjin. The total area of wetland patch was increased from 3120.89 km2 in 1999 to 3281.34 km2 in 2007, then to 3297.43 km2 in 2015, and would be decreased  to 3285.78 km2 in 2023. The percentage of natural wetland would be decreased continuously from 33.0% to 30.2%, while that of constructed wetland would be increased to 69.9%. Twenty variables were selected and divided into two types for establishing a driving factors index system. The analysis of driving force for the wetland landscape changes showed that the first principal component had positive correlations with GDP, per capita GDP, total fiscal revenue, secondary industry percentage, total population, non-agricultural population, freight turnover quantity, passenger turnover quantity, and port throughput, and negative correlations with primary industry percentage, tertiary industry percentage, and cropland area.
    Dynamic changes of urban heat environment pattern in Xi’an of Northwest China.
    FENG Xiao-gang1**, SHI Hui2
    2012, 31(11):  2921-2925. 
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    Based on the thermal band data of TM/ETM+ and by using mono-window algorithm, this paper studied the distribution pattern and dynamic characteristics of heat island landscape in Xi’an from 1995 to 2006. In the study period, there was an obvious urban heat island effect in Xi’an, and the thermal field spatial distribution pattern was identical with the builtup areas in the City. With the urbanization process of Xi’an, its thermal environment pattern presented a trend of increasing heterogeneity. In the eastwest and northsouth directions through the center of Xi’an, the temperature profile had a close relationship with the land use/land cover. Construction land surface had the highest temperature, while water area had the lowest one. The relationship between the land surface temperature and the land use/land cover was in the order of construction land > unused land > cropland > grassland > woodland > water area. The surface temperature showed a positive correlation with the NDBI index, and a negative correlation with the NDVI index.
    Variation patterns of different types of vegetation in Anhui Province of East China in 2000-2009 in relation to air temperature and precipitation.
    FENG Yan1,2, HE Bin-fang2,3**, TANG Huai-ou4, XUN Shang-pei2,3, WU Bi-wen2,3
    2012, 31(11):  2926-2934. 
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    In order to understand the responses of different types of vegetation in Anhui Province of East China to climate elements, this paper analyzed the recent ten years spatiotemporal variation patterns of the vegetations and their correlations with air temperature and precipitation, based on the monthly Normalized Difference Vegetation Index (NDVI) data from Moderate Resolution Imaging Spectroradiometer (MODIS), the daily temperature/precipitation data from 80 meteorological stations, and the land cover data in 2000-2009. The results showed that in recent ten years, the vegetation index of different land cover types in the Province had different change trends. The vegetation index increased significantly in crop planting area and cities, but had less change in other areas. Forestland had the highest average vegetation index, followed by crop planting area, and then, urban area. The monthly variation of the vegetation index presented a doublepeak pattern in crop planting area, but a singlepeak pattern for other land cover types. The monthly average NDVI in the Province had a significant positive linear correlation with the monthly mean temperature, and a positive nonlinear correlation with the monthly total precipitation. A threshold value of precipitation existed in its effect on NDVI. There was a weak positive correlation between the NDVI and the inter-annual change of temperature/precipitation. The partial correlation coefficient between vegetation index and air temperature was the maximum in forestland and the minimum in crop planting area, and was larger in natural vegetation area than in artificial vegetation area. The partial correlation coefficient between vegetation index and precipitation was contrary. In the majority area of middle Huaibei plain and northern Jianghuai (nonirrigable land), the vegetation was co-driven by air temperature and precipitation; in some minority middle Huaibei plain grids and water grids, the vegetation was solely driven by precipitation; and in the other areas, the vegetation was solely driven by air temperature, except in some water grids, it was driven by nonclimate factors.
    Strontium isotopes in forest ecosystem study: A review.
    LI Fu-shan1,2, HAN Gui-lin1**
    2012, 31(11):  2935-2942. 
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    Radiogenic strontium (Sr) isotope (87Sr/86Sr) is an effective tool for tracing the sources and behaviors of Sr in the environment, playing a very important role in understanding the structure and function of terrestrial ecosystems, whereas nontraditional stable Sr isotope (δ88/86Sr) can reveal the translocation of the previously neglected cations in vegetations. This paper reviewed the biogeochemical cycling of Sr in forest ecosystems and the related quantification methods, elaborated the principles of using the nonfractionation characters of 87Sr/86Sr in the lowtemperature hypergenic environment to trace the sources and cycling paths of nutrient cations, the principles of using δ88/86Sr to trace the biological fractionation processes in ecosystems, and the mechanisms of the biogeochemical cycling of Sr in vegetations, and summarized the applications of Sr isotopes in the studies of environmental changes and of the evolution of ecosystems. It was suggested that the combined application of 87Sr/86Sr and δ88/86Sr could be the future direction in the study of terrestrial ecosystems.  
    Research advances in weed community and its adaptive evolution in croplands as affected by long-term fertilization.
    WAN Kai-yuan1, PAN Jun-feng1,2, TAO Yong1, TANG Lei-lei1, CHENG Chuan-peng1, CHEN Fang1**
    2012, 31(11):  2943-2949. 
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    Weeds can compete with crops for resources, resulting in the yield reduction of crops, while play an indispensable role in maintaining the ecological balance of cropland and its sustainable utilization. The application of chemical fertilizers not only greatly accelerated the evolution of soil fertility, but also directly affected the weed growth, its community succession, and genetic evolution in croplands. Therefore, how to scientifically constitute a nutrient management strategy in cropland has become a realistic issue in modern agriculture. This paper comprehensively reviewed the related literatures, and summarized the effects of longterm fertilization regimes on the weed species, community structure, and genetic evolution. Through thoroughly analyzing the weaknesses of the current weed management, it was suggested that the weed control in croplands should be balanced with weed biodiversity, and the research on the long-term fertilization regimes affecting weed genetic diversity and its molecular ecological adaptability should be strengthened, which would have significance in assessing the genetic diversity of weeds under selective fertilization pressure, the potential of weed survival and evolution, and the molecular mechanisms of weed adaptive evolution, so as to supply a broader sense for the comprehensive management of weeds in croplands.
    Application potential of earthworm in bio-remediation of heavy metals contaminated soil.
    CHEN Xu-fei, ZHANG Chi**, GAO Yun-hua, DAI Jun
    2012, 31(11):  2950-2957. 
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    This paper summarized the characteristics of different ecological categories of earthworms and their ecological functions in soil, the effects of the earthworms on soil heavy metal accumulation and bioavailability as well as their mechanisms in affecting heavy metal activation, and pointed out the deficiencies and future directions in the study of related biochemical mechanisms. Aimed at the present situations about the applications of earthworm in agricultural and environment fields, it was suggested that earthworm could be used as a biological resource for the phytoextraction of the heavy metals in contaminated soil, more laboratory simulation studies using real soil and field experiments would be required, and to further approach the related techniques for selecting and breeding native earthworm species and for organic matter addition would be the important issues in the future.  
    Research and application advances in ecological carrying capacity.
    XIANG Yun-yun, MENG Ji-jun**
    2012, 31(11):  2958-2965. 
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    he study of ecological carrying capacity is an important basis for the settlement of resource shortage and environment deterioration and the realization of regional sustainable development, and also, one of the hot spots in geography, ecology, and economics. After reviewing the related  research achievements, this paper elucidated the connotation of ecological carrying capacity, i.e., a representation of the supporting function and compressive stress of complex ecosystem, introduced the universal measuring methods of ecological carrying capacity, e.g., net primary productivity (NPP), ecological footprint (EF), balance of supply and demand, evaluation with comprehensive indices, and systematic modeling, and presented the research progress in the ecological carrying capacity of the regions being more concerned, including watersheds, ecological fragile areas, cities, agricultural areas, and tourism areas. The deficiencies in current studies, such as the shortage of complete scientific research system, the ambiguity of threshold value’s ecological meaning, the lack of time series study, and the absence of spatial pattern analysis, were summarized, and accordingly, the development trends in action mechanisms, model construction, and practical application were prospected.  
    Environmental biology of Bellamya sp. in regulating pond water quality.
    ZHOU Lu-hong1,2, GU Xiao-hong1**, ZENG Qing-fei1, MAO Zhi-gang1,2, GAO Hua-mei3, SUN Ming-bo1,2
    2012, 31(11):  2966-2975. 
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    Three micro-scale controlled experiments were established to examine the ecological function of Bellamya sp. and their affecting mechanisms upon water. Due to the N and P release through the Bellamya sp. metabolism under controlled conditions, the concentrations of different N and P forms in water were obviously increased. After 430 hours incubation, the concentrations of dissolved total nitrogen (DTN) and dissolved total phosphorus (DTP) in water were increased by 0.73-2.56 times and 1.85-3.41 times, respectively. Under the high nutrient concentrations, the N and P release by Bellamya sp. was inhibited. Meanwhile, Bellamya sp. showed a positive effect on the shortterm deposition of suspended particulate matter (POM), which was related to the constituents and concentrations of POM. The sedimentation rates in both kaolin and eutrophic water with high initial turbidity showed significant positive relationship with snail density. Furthermore, Bellamya sp. greatly reduced the chlorophylla concentration in water in a short period, and the removal rate was positively correlated with snail density. However, the chlorophylla concentration was increased rapidly with increasing incubation time. The feeding activities of Bellamya sp. and the consequent nutrient release stimulated the chlorophyta instead of cyanobacteria as the dominant species.
    Purification effect of vegetative filter strip on suspended solids in surface runoff: A simulation study.
    DENG Na1, 2**, LI Huai-en1, SHI Dong-qing1
    2012, 31(11):  2976-2980. 
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    Mathematical model is an important tool for the planning and design of vegetative filter strips (VFS). Through the analysis on the purification mechanisms of VFS to suspended solids in surface runoff, a mathematical model which coupled the field scale mechanism model VFSMOD and the revised soil erosion model MUSLE was designed to simulate the purification effect of VFS on the suspended solids in surface runoff. The applicability and performance ability of this coupling model were validated by field plot experiment. The results showed that the relative deviations between the simulated and measured values of the concentrations of suspended solids were within ±20%, and the determination coefficients between the simulated and measured values were 0.98, suggesting that this coupling model had a high precision and was superior to VFSMOD model, being able to be used as a tool for the planning and design of VFS in China.