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    10 February 2013, Volume 32 Issue 2
    Body size and stem- and leaf allometry of Stellera chamaejasme in degraded alpine grassland.
    LI Yu, ZHAO Cheng-zhang**, HOU Zhao-jiang, MA Xiao-li, ZHANG Qian
    2013, 32(2):  241-246. 
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    The growth patterns of leaf and stem decide the light capture pattern of plants and the acreage of the material exchange between plants and external environment, whereas the biomass allocation is a main approach to study the plant life history strategies. Taking the degraded alpine grassland in the upper reaches of Shiyang River, Gansu Province of Northwest China as a case, the method of standardized major axis (SA-M) estimation was adopted to study the effects of Stellera chamaejasme- stem size on the biomass allocation in leaf and stem, and on the leaf area supporting efficiency. There existed an allometric relationship between the stem dry mass and the LMA, individual leaf area, and leaf dry mass, with a SMA slope of 0.781 (95% confidence interval, CI=0.71-0.94), 0.824 (CI=0.77-0.95), and 0.856 (CI=0.79-0.99), respectively. The S. chamaejasme with bigger stem had higher leaf biomass allocation percentage and leaf area supporting efficiency, and in the meantime, had higher LMA, indicating that the bigger S. chamaejasme mainly adopted an adaptive strategy of high resource-use efficiency, while the smaller one mainly employed an adaptive strategy of fast growth.
    Response of reproductive allocation of Stellera chamaejasme population in alpine grassland to altitude.
    ZHANG Qian, ZHAO Cheng-zhang**, MA Xiao-li, HOU Zhao-jiang, LI Yu
    2013, 32(2):  247-252. 
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    Reproduction has a very close relationship with species survival and development, and is the core in the study of plant life history. The environmental factors under the restriction by altitude have significant effects on the reproductive allocation of plants. In July 2010, a quadrat
    investigation was conducted to study the characteristics of the reproductive allocation of S. chamaejasme population at four altitudes with a gradient from 2700 m to 3000 m. With the increasing altitude, the aboveground biomass of S. chamaejasme presented a decreasing trend, but the total flower biomass and the plant height increased after an initial decrease, and the reproductive allocation had an increasing trend. Along the altitude gradient, the reproductive allocation had a significant negative correlation with the total aboveground biomass (except at altitude 2800 m), but less correlation with the plant height (except at altitude 3000 m). The reproductive allocation of S. chamaejasme population was limited by plant body size, and the limitation by total aboveground biomass was far larger than the limitation by plant height, indicating that with the increasing altitude, S. chamaejasme population could ensure its reproductive success via reducing the plant body size to decrease the resource consumption and increasing the allocation of the obtained limited resources to flower biomass.
    Responses of the spatial pattern of Stellera chamaejasme’s aboveground biomass to topography in degraded alpine grassland.
    HOU Zhao-jiang, ZHAO Cheng-zhang**, LI Yu, ZHANG Qian, MA Xiao-li
    2013, 32(2):  253-258. 
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    The spatial pattern of aboveground biomass is an important content of species distribution pattern, whereas the environmental heterogeneity caused by the topographical differences in the scope of small scales is the environmental basis for the formation and evolution of this pattern. Based on the field survey in August 2011 and with the help of GIS and SPLUS software, the generalized additive model (GAM) was applied to study the spatial distribution pattern of S. chamaejasme population in degraded alpine grassland, and to quantitatively analyze the response mechanisms of the spatial pattern of S. chamaejasme’s aboveground biomass to topographical factors. Topographical factors had definite effects on the aboveground biomass of S. chamaejasme, with the sequence of aspect > slope > elevation > plane curvature > profile curvature. The contribution degree of aspect and slope to the spatial pattern of S. chamaejasme’s aboveground biomass was 3.75 and 1.48, respectively, while the contribution of other topographic factors was relatively lower. The aboveground biomass of S. chamaejasme had a uniform distribution in the gradients of elevation, plane curvature, and profile curvature, but presented an opendown parabola tendency in aspect gradient and an openup parabola tendency in slope gradient. The relationships between the spatial heterogeneity of S. chamaejasme’s aboveground biomass and topographic factors reflected the response mechanisms and growth strategies of S. chamaejasme under the effects of the redistribution of water and heat conditions.
    Responses of plant community diversity and soil factors to slope aspect in alpine meadow.
    LIU Min-xia1,2**, WANG Gang2
    2013, 32(2):  259-265. 
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    As a main topographic factor in mountainous region, slope aspect is an indirect environmental factor inducing the differences of plant community species diversity and structure. Slope aspect can affect light intensity, soil temperature, soil moisture, and soil nutrients, and accordingly, produce important effects on the biodiversity, plant growth, productivity, and ecosystem functions. This paper studied the variation characteristics of plant community species diversity and their relationships with environmental factors on different slope aspects of an alpine meadow on QinghaiTibetan Plateau. In the habitat gradient from southfacing slope to northfacing slope, soil moisture content had a variation trend of northfacing slope > westfacing slope > southfacing slope, light intensity and soil temperature were in the sequence of southfacing slope > westfacing slope > northfacing slope, whereas soil nutrient contents were in the order of northfacing slope > westfacing slope > southfacing slope (except that the contents of soil total N and organic carbon were north-facing slope > south-facing slope > west-facing slope). The plant community species diversity in the habitat gradient was north-facing slope > westfacing slope > south-facing slope. Grasses were the main functional groups on south-facing slope, while forbs were the main ones on northfacing slope. Pearson’s correlation analysis showed that light, heat, water, and soil properties all affected the variations of species diversity along the habitat gradient from south-facing slope to north-facing slope, and soil moisture content was the key factor determining the variations of the plant community diversity.
    Distribution patterns of the biomass of Avena sativa and Vicia villosa in response to the component density ratio  of the grass species in a mixedseeding grassland in alpine region of Qilian Mountains, Northwest China.
    ZHANG Jing, ZHAO Cheng-zhang**
    2013, 32(2):  266-270. 
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    Plant density gradient can restrict the distribution pattern of plant biomass, and thus, affect the performances of mixedseeding grassland in ecology and production. From June to September 2010, a replacement series experiment was conducted to establish a piece of grassland with mixedseeding of Avena sativa and Vicia villosa in the upper reaches of Shiyang River, Gansu Province of Northwest China. Five treatments were installed, according to the relative density of A. sativa to V. villosa, i.e., 8∶2, 6∶4, 5∶5, 4∶6, and 2∶8, with the effects of the density gradient on the distribution patterns of the biomass of A. sativa and V. vilosa studied. With the decreasing relative density of A. sativa and the increasing relative density of V. villosa, the root-biomass of A. sativa decreased first and increased then, and decreased lastly, while that of V. villosa was in the contrary. The stem and leaf biomass of A. sativa and V. villosa increased after an initial decrease. With the growth of the grasses, the allocation ratio of the stem biomass of A. sativa and V. vilosa in the five treatments increased gradually, while that of the leaf and root biomass was in adverse. The adjustment of the resource allocation strategies of the mixedseeding grasses under the restriction of plant density gradient demonstrated the asymmetry of the light competition of plant aboveground parts and the symmetry of the resource competition of underground parts. The climbing growth of V. vilosa and its pressure on A. sativa stem made the plants have higher allocation ratio of stem biomass, and achieve the maximum resource use.
    Pattern-controlling relationships of dominant species in degraded grassland of Melica przewalskyi.
    GAO Fu-yuan1, ZHAO Cheng-zhang2**
    2013, 32(2):  271-278. 
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    In this paper, the methods of spatial point pattern and Ripley’s K function were adopted to study the spatial distribution, spatial association, and patterncontrolling relationships between Melica przewalskyi and Stipa krylovii in degraded alpine grassland in the upper reaches of Shiyang River, western China, aimed to detect the interspecific patterncontrolling relationships of dominant species during retrogressive succession. Five sampling plots were installed according to the time series, i.e., patch not formed (CK), patch formed (A), patch spread (B), patch stable (C), and patch degraded (D). During the process of retrogressive succession (from CK to D), the spatial distribution pattern of S. krylovii transferred from random to aggregative, and the association between M. przewalskyi and S. krylovii transferred from significant negative to not significant, with the significance decreased after an initial increase. In plots A, B, and C, M. przewalskyi showed patterncontrolling relationships to S. krylovii at 0-15, 0-12, and 0-10 cm scales, but the patterncontrolling relationships did not appear at plots CK and D. By altering microhabitats, the species with bigger size, larger scale, and stronger competition capability forced other species changed their distribution pattern and presented regular distribution, and thus, formed pattern-controlling relationships to other species.
    Spatial distribution patterns of root length density of Avena sativa and Vicia villosa in their mixed-sowing grassland in alpine region.
    SHENG Ya-ping, ZHAO Cheng-zhang**, ZHANG Jing, REN Heng, LI Li-li
    2013, 32(2):  279-284. 
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    Plant can adjust its root length density and distribution pattern to optimize its resources utilization pattern. In this study, the mixedsowing grassland of gramineous grass Avena sativa and leguminous grass Vicia villosa with the density ratio of 0∶10 (CK1), 8∶2 (Ⅰ), 6∶4 (Ⅱ), 5∶5 (Ⅲ), 4∶6 (Ⅳ), 2∶8 (Ⅴ), and 10∶0 (CK2) was established in the upper reaches of Shiyang River in Sunan County of Gansu Province, Northwest China in 2010, aimed to study the spatial distribution patterns of root length density of the two mixedsowing grasses. The root length density (RLD) of the two grasses was greater in mixed culture than in monoculture. With the decrease of A. sativa density in mixedsowing grassland, the RLD of the grass had a gradual increase, showing a phenomenon of high A. sativa density and low A. sativa RLD. Spatially, the RLD of A. sativa and V. villosa had obvious difference. A. sativa roots were mainly distributed in 0-25 cm soil layer, while V. villosa roots were concentrated in 0-15 cm soil layer. The hierarchical distribution of the roots changed their competition pattern, and the difference in the vertical distribution gradually changed the root structure and morphology. In the treatments except CK1 and CK2, the taproot growth was restrained, while the lateral root growth was promoted. The spatial hierarchical distribution of the lateral roots in the mixed-sowing grassland changed the resource utilization pattern, and gradually optimized the root length density configuration pattern, which achieved the goal of maximizing the resources utilization from soil.
    Spatial patterns of soil moisture and vegetation coverage in Melica przewalskyi patches in degraded alpine grassland of Qilian Mountains, Northwest China.
    SHI Li-li, ZHAO Cheng-zhang**, FAN Jie-ping, ZHANG Jing, ZHANG Jun-xia
    2013, 32(2):  285-291. 
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    Soil moisture is the key factor in the formation and evolution of vegetation pattern. The spatial heterogeneity of soil moisture has an important significance in understanding the response mechanisms of plants in arid grasslands to environment. Meanwhile, at small scales, vegetation condition is the important driving factor to the spatial heterogeneity of soil moisture. By the methods of geo-statistics, this paper studied the spatial variability of surface soil (0-30 cm) moisture content and vegetation coverage as well as their relationship in the Melica przewalskyidominant patches in degraded grassland on the northern slope of Qilian Mountains, Northwest China. In the M. przewalskyidominant patches, both the surface soil moisture content and the vegetation coverage were in line with normal distribution. In different layers at 0-30 cm depth, soil moisture content had a high degree of spatial heterogeneity, and 80.93%-87.34% of the heterogeneity was caused by spatial autocorrelation. The spatial autocorrelation in vegetation coverage was found within the distance from 4.09-6.91 m, whereas the spatial heterogeneity of vegetation coverage caused by stochastic factors at <1 m scale accounted for 12.66%-19.07%. The spatial heterogeneity of soil moisture content in M. przewalskyidominant patches showed an obviously layered and patchy structure, and the high and low moisture values had a mosaic distribution. Through physiological integration, M. przewalskyi affected, and in definite extent, altered the spatial distribution of soil moisture at small scales, and thus, achieved the maximum utilization of soil water resource, and improved the adaptability and competitiveness of M. przewalskyi populations in arid habitats.
    Spatial patterns of Stellera chamaejasme and Melilotoides ruthenicus var. inschanicus populations in alpine grassland.
    DANG Jing-jing, ZHAO Cheng-zhang**, REN Heng, YANG Quan, ZHA Gao-de
    2013, 32(2):  292-298. 
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    Different types of spatial pattern and spatial association of plant populations can reflect their adaptive strategies in using environmental resources, and can reveal the population biology under disturbances. By using point pattern analysis, this paper studied the spatial pattern and spatial association of Stellera chamaejasme and Melilotoides ruthenicus var. inschanicus at their different succession stages on the northern slope of Qilian Mountains, Northwest China. With the degradation of natural grassland, the plant density, plant height, and aboveground biomass of S. chamaejasme population had a persistent increase, the spatial pattern transferred from aggregative into random or regular. In the meantime, the plant height of M. ruthenicus var. inschanicus population decreased gradually, its plant density and aboveground biomass decreased after an initial increase, and the spatial pattern transferred from aggregative or regular to random. The spatial association between S. chamaejasme and M. ruthenicus var. inschanicus populations transferred from increasingly positive to not significant. During the degradation of natural grassland, the decline of Stipa krylovii population at the upper layer of the community and the differences in the plant height between S. chamaejasme and M. ruthenicus var. inschanicus made an asymmetric competition of light resources, which led to the regulation of the resource allocation strategies of S. chamaejasme and M. ruthenicus var. inschanicus, and affected the spatial pattern and spatial association of the two plants.
    Spatial pattern and spatial association of Melica przewalskyi and Artemisia frigida in degraded grassland.
    MA Xiao-li1,2, ZHAO Cheng-zhang1**, ZHANG Qian1, LI Yu1, HOU Zhao-jiang1
    2013, 32(2):  299-304. 
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    Spatial pattern and spatial association are the important means for the study of population diffusion, community succession, and interactions between organisms and environment. In this paper, point pattern method was applied to study the plant height, aboveground biomass, spatial pattern, and spatial association of Melica przewalskyi and Artemisia frigida at their different succession stages in the upper reaches of Shiyang River in Sunan County, Gansu Province of Northwest China. At the stages of no patch formation (CK) and patch formation (A), the M. przewalskyi population showed a clumped pattern at all scales; while at diffusion stage (B), stable stage (C), and degradation stage (D), the clumped pattern transferred to random, and, with the decreases of clumped scale and clumped intensity, the plant height and aboveground biomass of M. przewalskyi decreased after an initial increase. The spatial distribution pattern of A. frigida at its different succession stages all presented a transition from clumped to random, and, with the increase of clumped scale, the clumped intensity increased, and the plant height and aboveground biomass decreased after an initial increase. At the stages CK, A, and D, the spatial association between M. przewalskyi and A. frigida was significantly positive; at stage B, the spatial association transferred from significantly negative to not significantly. The corresponding relationships of the changes in plant height and aboveground biomass with the populations’ spatial pattern and spatial association scale transformation under the interference of grazing reflected the populations’ competition and ecological adaptable strategies in degraded grassland.
    Abundance of Oedaleus asiaticus in natural grassland in the upper reaches of Heihe River, western China in relation to topography.
    ZHANG Jun-xia, ZHAO Cheng-zhang**, YIN Cui-qin, LI Li-li, HOU Zhao-jiang, ZHANG Jing
    2013, 32(2):  305-310. 
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    The micro-scale environmental heterogeneity caused by topographical diversity is an environmental foundation underlying the formation and evolution of biogeographic pattern. Based on the field survey in July-August 2009, and with the help of GIS and S-PLUS software, a quantitative analysis with generalized additive model (GAM) was made on the relationships between the Oedaleus asiaticus abundance and topographical factors such as altitude, aspect, slope, and profile curvature in the natural grassland on northern slope of Qilian Mountains, the upper reaches of Heihe River. The model for O. asiaticus performed well, and could actually reflect the spatial distribution of O. asiaticus abundance. Different topographical factors had different effects on the spatial distribution of O. asiaticus abundance, among which, elevation and profile curvature showed dominant effects. With the increase of elevation, the O. asiaticus abundance showed a more or less reverse “V” trend. The abundance had a positive correlation with increasing altitude at altitude 2380-2560 m, but a negative correlation with the increasing altitude at altitude >2560 m. The O. asiaticus was mainly distributed in the regions with a profile curvature <0. There existed a positive correlation between the abundance and profile curvature when the profile curvature was <-1.6, and a negative correlation when the profile curvature was >-1.6. The relationships between the abundance of O. asiaticus and topographical factors as well as the spatial distribution pattern of O. asiaticus abundance indicated that the redistribution of water and heat conditions due to topographical factors caused the heterogeneity of the spatial distribution pattern of O. asiaticus.
    Vertical differentiation of plant species diversity and biomass in alpine grassland in the middle section of Tianshan Mountains southern slope, Xinjiang of Northwest China.
    LIU Yan-yan1, HU Yu-kun1**, WANG Xin1,2, GONG Yan-ming1
    2013, 32(2):  311-318. 
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    Elevation is one of the decisive factors of mountain plant species, population, community, and ecosystem. In this paper, an investigation was conducted on the changes of plant diversity and biomass in alpine grassland along an elevation gradient (2460-3260 m) on the southern slope of Tianshan Mountains. With the increase of elevation, environmental factors changed. The species richness index and Simpson dominance index appeared a unimodal pattern and peaked at the altitudes 3060 m and 2760 m, respectively, and the Shannon index and evenness index increased. The biomass also presented a unimodal pattern, and the above and belowground biomass peaked at altitudes 3160 m and 3060 m, respectively. Our results supported the “intermediate height expansion” theory. The belowground biomass was mainly concentrated in 0-10 cm soil layer, accounting for 63.4%-94.7% of the total belowground biomass, and the average root/shoot ratio was 62. Air temperature and soil water content were the main environmental factors affecting the species diversity. Besides water and heat factors, soil pH was the factor limiting the plant growth, whereas soil available P was the factor limiting the plant root growth. Correlation analysis indicated that species richness was very significantly correlated with aboveground biomass and significantly correlated with belowground biomass, Shannon index was significantly correlated with aboveground biomass, and species diversity had a linear correlation with total biomass.
    Heterogeneity of shallow soil temperature in the forest gaps of Pinus koraiensisdominated broadleaved mixed forest.
    LI Meng1,3, LIU Yang2, DUAN Wen-biao3**
    2013, 32(2):  319-324. 
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    Taking the Pinus koraiensisdominated broadleaved mixed forest in Xiaoxing’an Mountains of Northeast China as test object, and by using grid method, the measurement plots of forest gaps were established to continuously measure the shallow soil temperature, with its spatiotemporal heterogeneity in the gaps during growth season analyzed by the classic statistics and geostatistical methods. There existed heterogeneity in the shallow soil temperature among different measurement plots. The intensity and scale of the spatial heterogeneity changed with time, and the complex degree of the patch shapes of mean monthly shallow soil temperature also differed. The mean monthly temperature at 5 cm soil depth was the highest in July, followed by in the sequence of June, August, and September, whereas the mean monthly temperature at 20 cm soil depth was the highest in July, followed by in the sequence of August, June, and September.  The mean monthly maximum shallow soil temperature was not fixed. In the same months, the mean temperature at 5 and 20 cm soil depth was the highest in bare ground, followed by in forest gap, and the lowest in understory.
    Characteristics of soil mineral nutrient composition in Vaccinium uliginosum community under Larix olgensis forest in Changbai Mountains of Northeast China.
    CHEN Ying-min1, WANG He-xin1**, LI Gen-zhu1, XU Guo-hui1, YU Dong-mei2, MIAO Ying-qiu1, NIU Li-hua3
    2013, 32(2):  325-331. 
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    Taking the Vaccinium uliginosum community under Larixolgensis forest in Changbai Mountains as test object, an investigation was conducted on the contents of N, P, K, Ca, Mg and S and their composition characteristics in various soil layers. The root system of the V. uliginosum community was mainly distributed in the surface soil which was covered by moss and by the litters from Larix and Vaccinium, and few were in the mineral soil layer which was developed from pozzuolana. As compared with those in larch litter, the total N, P, and K contents in two moss taxa, Sphagnum and Plytrichum, were obviously higher, the total Ca content was slightly lower, whereas the total Mg and S contents were similar. These results suggested that dead mosses were the main sources of the N, P, and K for the V. uliginosum community. The litters of V. uliginosum, though their proportion in litter layer was small, still played an important role in nutrient supply, because of their higher contents of N, P, Ca, and S. From the top towards the bottom, the soil was divided into five layers, i.e., live moss layer (L), dead moss layer (F), semidecomposed layer (A1), peat layer (A2), and pozzolanic layer (C). The soil total N content showed a decline pattern in the order of F>L>A1>A2>C, the total P was in the order of L≈F≈A1>A2>C, the total K was L≈F<A1<A2<C, the total S was L≈F≈A1>A2>C, the total Ca was L≈F>A1, and the total Mg was L<F<A1. In A2 and C layers, the contents of available mineral elements N, P, K, Ca, and Mg, except for S, in C layer were obviously lower than those in A2 layer. In addition, the higher pH value in C layer than in A2 layer restricted the root growth of V. uliginosum.
    Temporal variation pattern and its affecting factors of soil water content in a subtropical evergreen broadleaved forest in Ailao Mountains, Southwest China.
    YU Lei1,3, ZHANG Yi-ping1,2**, SHA Li-qing1,2, SONG Qing-hai1,3, TAN Zheng-hong1, ZHOU Wen-jun1,3, WU Chuan-sheng1,2,3
    2013, 32(2):  332-336. 
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    Based on the soil water content data from the Flux Observation System of ChinaFlux installed in a subtropical evergreen broadleaved forest in the Ailao Mountains, Yunnan Province of Southwest China, the temporal variation and its affecting factors of soil water content in the forest were analyzed, aimed to further understand the characteristics and the annual variation pattern of the soil water content, and to provide basis to study the carbon sequestration ability, potential, and rate of local forest. In this forest, the soil water content at different depths more or less presented a single peak curve. With decreasing depth, the soil water content decreased, and its fluctuation range also had a gradual decrease, with the minima occurred in March and the maxima in July, August, and September. In the 0-100 cm profile, the soil water content in different layers ranged from 17.7% to 39.5%, with the minima and the least fluctuation at the depth 100 cm. Overall, the soil water content was higher in rainy season than in dry season. The soil water content was mainly affected by precipitation, soil temperature, and relative humidity (P<0.05). The maximum soil water content at the depth 5 cm in the subtropical evergreen broadleaved forest in Ailao Mountains was about 38%.
    Effects of continuous planting poplar on the soil nutrient contents, microbial biomass, and enzyme activities in lower reaches of Liaohe River Plain, Northeast China.
    CAI Li-jia1,2, XU Yong-gang1, YU Wan-tai1**, HU Bao-zhu3, WU Ya-xi3
    2013, 32(2):  337-343. 
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    Taking the farmland and the poplar (Populus × liaoningensis) plantation stands with different successive rotation durations (the first rotation of tenyearold, the second rotation of sixyearold, and the second rotation of fifteenyearold) in Jixie Forest Farm in Xinmin City, Liaoning of Northeast China as test objects, an investigation was made on the soil nutrient contents, microbial biomass, and enzyme activities, aimed to evaluate the effects of returning farmland to forestland on the soil chemical and biological properties. After returning farmland to forestland, and with the increasing stand age and successive rotation duration, the soil pH presented an increasing trend, whereas the soil nutrient contents and microbial biomass increased after an initial decrease. The soil basal respiration and catalase activity were significantly higher in poplar stands than in farmland, whereas the soil urease and neutral phosphatase activities were in opposite trend. The soil fertility indices except pH all decreased with increasing soil depth. All the results indicated that the soil fertility tended to be declined at the early stage of afforestation, but gradually increased with the increasing stand age and successive rotation duration. These findings could offer references for the returning farmland to forestland in Northeast China.
    Impacts of elevated atmospheric ozone concentration on the photosynthetic physiology of Phyllostachys edulis.
    LI Ying-chun1, LI Ying1,2,CHEN Shuang-lin1**, ZHUANG Ming-hao1, GUO Zi-wu1, YANG Qing-ping1
    2013, 32(2):  344-350. 
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    In this study, open-top chambers (OTCs) were employed to approach the impacts of elevated atmospheric ozone (O3) concentration on the photosynthesis of Phyllostachys edulis. Five treatments were installed, i.e., CF (background atmosphere after filtrated by activated carbon, 22-25 nL·L-1), NF (directly introduce the background atmosphere to the gas chamber, 40-45 nL·L-1), T1 (92-106 nL·L-1 of O3, averagely 100 nL·L-1), T2 (142-160 nL·L-1 of O3, averagely 150 nL·L-1). Under different O3 concentrations, the diurnal variations of P. edulis leaf Pn and Tr represented onepeak curves. With the increasing concentration of O3, the diurnal variations of the leaf Gs, Ci, and Ls trended to be simplified, while that of WUE became stable gradually. Under higher concentrations (≥ 100 nL·L-1) O3, the diurnal means of Pn, Ls, and WUE and the contents Chl, Chl-a, Chl-b, and Car decreased significantly, those of Gs and Tr had a significant increase, while the diurnal mean of Ci and the composition of photosynthetic pigment changed less. In treatments T1 and T2, the Pn,Tr, and Gs were significantly correlated with the environmental factors VpdL, Tair, Ca, and RH, and the Pn and Tr were significantly correlated with the PPED while the Gs was less correlated with the PPED. All the results indicated that 100 and 150 nL·L-1 of O3 could induce the leaf stomatal or nonstomatal limitation of P. edulis, respectively, and the stoma became insensitive to the environment, which impacted the leaf’s normal feedback mechanisms, increased leaf evapotranspiration, and inhibited the degradation or synthesis of photosynthetic pigments, exerting serious negative effects on the photosynthesis and dry matter accumulation of P. edulis.
    Allelopathic effects of aqueous extracts from native Vitex negundo on the growth and photosynthesis traits of Eupatorium odoratum.
    PAN Yu-mei1,2, TANG Sai-chun2**, WEI Chun-qiang2, LIN Chun-hua2,3
    2013, 32(2):  351-357. 
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    A pot experiment was conducted to study the allelopathic effects of the aqueous extracts from the stem and leaf of native plant Vitex negundo on the growth and photosynthesis traits of invasive weed Eupatorium odoratum, aimed to clarify the action mechanisms of the native plant in the replacement control of the invasive weed. With the treatment of the aqueous extracts, both the plant height and the relative chlorophyll content of E. odoratum decreased, and the decrements were positively correlated the concentration of the aqueous extracts. The aqueous extracts from V. negundo stem and leaf (except for the low concentration of stem aqueous extracts) had negative effects on the leaf number, total leaf area, branch number, biomass, and relative growth rate of E. odoratum, with stronger effects of leaf extracts than of stem extracts. As compared to the control, the maximum photosynthetic rate (Pmax), light saturation point (LSP), and apparent quantum yield of E. odoratum treated with the aqueous extracts all decreased, while the light compensation point (LCP) increased. The photosynthesis response curve of E. odoratum decreased with the increasing concentration of the stem and leaf extracts, suggesting that both the stem and leaf aquatic extracts of V. negundo had inhibitory effects on the photosynthesis, morphology and growth of E. odoratum, and thus, native plant V. negundo could be used as the target species for the replacement control of E. odoratum invasion in China.
     
    Impacts of zinc, benzo\[a\]pyrene, and their combination on the growth and antioxidant enzymes activities of wheat (Triticum aestivum L.) seedlings.
    LI Yue, XIE Shi, CHEN Zhong-lin, XU Su-nan, ZHANG Li-hong**
    2013, 32(2):  358-362. 
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    A hydroponic experiment was conducted to study the impacts of zinc (Zn), benzo\[a\]pyrene (B\[a\]P), and their combination on the growth and antioxidant enzymes activities of Triticum aestivum seedlings. As compared with CK, the biomass and plant height of the seedlings under the stresses of Zn, B\[a\]P, and their combination decreased. Under the combined stress of 300 mg·L-1 of Zn and 54 mg·L-1 of B\[a\]P, the above and underground dry mass decreased by 36.4% and 51.7%, respectively, and the decrements were obviously larger than those under single stress. In all treatments with Zn and/or B\[a\]P, the superoxide dismutase (SOD) activity presented a trend of increasedecreaseincrease and was lower than that in CK, whereas the peroxidase (POD) and catalase (CAT) activities decreased after an initial increase. Under combined stress, the POD activity was the highest, while the CAT activity was the lowest. Under the single and the combined stress, the seedling’s growth was inhibited, being most obvious under combined stress. The joint action of Zn and B\[a\]P was of synergistic effect.
    Effects of nitrogen and phosphorus interaction on the tuber yield and its quality of Jerusalem artichoke.
    SUN Xiao-e, MENG Xian-fa, LIU Zhao-pu, LONG Xiao-hua**
    2013, 32(2):  363-367. 
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    In order to understand the effects of fertilizers interaction on the growth of Jerusalem artichoke, a field experiment with orthogonal design was conducted to study the effects of nitrogen (N), phosphorus (P), and their interaction on the tuber yield and its quality of J. artichoke “Nanyu No. 1”. Both N and P had significant effects on the tuber yield, its dry matter content, and total sugar, reducing sugar, and inulin contents (P<0.01). N and P interaction had significant effects on the tuber yield and its dry matter and reducing sugar contents (P<0.05), and extremely significant effects on the tuber’s total sugar and inulin contents (P<0.01). When the P fertilization rate was 135 kg P2O5·hm-2, its interaction with N was positive (synergistic) when the N fertilization rate was less than 180 kg·hm-2, but negative (antagonistic) when the N fertilization rate was above 180 kg·hm-2. When the N fertilization rate was 180 kg·hm-2 and the P fertilization rate was 135 kg P2O5·hm-2, the interactive effect of N and P increased, with the tuber yield and its dry matter, total sugar, reducing sugar, and inulin contents being the highest. Above all, the optimal basis fertilization for J. artichoke in Laizhou City of Shandong Province, East China would be 180 kg·hm-2 of N and 135 kg·hm-2 of P2O5.
    Fungal community structure during the decomposition of various aquatic plant litters.
    ZHENG Jiu-wen1,2, XING Peng2**, YU Duo-wei1, GUO Yuan2,3
    2013, 32(2):  368-374. 
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    Aquatic plants are the main primary producers in shallow lake, and their decomposition and mineralization have significant effects on the nutrient cycle in lake ecosystems. Fungi are one of the major decomposers in natural environments, but little is known about the composition and functions of fungal community during the decomposition of various aquatic plant litters. In this paper, various types of aquatic plant residues were separately added into undisturbed lake sediments and their upper water to study the characteristics of fungal community structure during the decomposition of these residues, based on the selection of suitable primers that can specifically amplify fungal 18S rRNA gene and on the construction of clone libraries and sequencing. The results showed that the primer pairs nu-SSU-0817/nu-SSU-1536 and nu-SSU-0817/nu-SSU-1196 were suitable to amplify the fungal 18S rRNA gene. Basidiomycota was the most common fungal taxa in water column, and Chytridiomycota was the most common one in surface sediments. Statistical analysis showed that there existed obvious differences in the fungal community structure in water column and surface sediments. This study would give further insight into the functions and niche differentiation of fungi during the decomposition of aquatic plant litters.
    Hatching behavior of relict gull Larus relictus in Hongjiannao of Shannxi Province, Northwest China.
    WANG Qing-xiong1, YANG Chao1, LIU Zheng2, XIAO Hong1**
    2013, 32(2):  375-379. 
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    By using e-Science information technology, an investigation was made on the hatching behavior of relict gull (Larus relictus) in the Hongjiannao of Shannxi Province, Northwest China from May to June, 2012. The diurnal hatching rhythms at different hatching stages were as the follows. At daytime, the times of exchanging hatching at the early, medium, and late stages of hatching averaged 6.40±0.45 (n=68), 2.20±0.12 (n=66), and 1.81±0.10 (n=48), the changes of sitting nest direction averaged 35.34±2.12 (n=68), 18.73±0.85 (n=66), and 15.17±0.75 (n=48), and the times of turning eggs over averaged 10.81±0.50 (n=68), 1014±0.55 (n=66), and 8.65±0.51 (n=48), respectively. At night, the times of exchanging hatching averaged 2.37±0.20 (n=62), 0.52±0.06 (n=60), and 0.53±0.07 (n=47), the changes of sitting nest direction averaged 16.16±0.67 (n=62), 4.28±0.31 (n=60), and 3.87±0.34 (n=47), and the times of turning eggs over averaged 6.58±0.40 (n=62), 4.22±0.30 (n=60), and 3.26±0.22 (n=47), respectively. On the days with strong wind and heavy rain, there existed significant differences in the times of exchanging hatching, the changes of sitting nest direction, and the times of turning eggs over at the same hatching stages, as compared with those on fine days. The time intervals of exchanging hatching by the parents were mainly 04:00-06:00, 08:00-10:00, and 12:00-14:00. At the late stage of hatching, the duration of sitting nest by the parents was as long as 601.14±31.16 min (n=56). It was suggested that the parents controlled the egg temperature via regulating the diurnal hatching rhythm to assure the normal development of egg embryo during daytime and night.
    Macrobenthic functional groups in Laizhou Bay, East China.
    LI Shao-wen1, LIU Yuan-jin2,3, LI Fan1, ZHANG Ying1, XU Zong-fa1, LU Zhen-bo1**, WANG Tian-tian3, ZHANG Ai-bo3
    2013, 32(2):  380-388. 
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    A four-cruise investigation was conducted on the macrobenthos at 20 sampling locations in Laizhou Bay in 2011, and the method based on functional group was adopted to study the functional groups and diversity of the macrobenthos. A total of 177 macrobenthic species were recorded, of which, polychaete, mollusk, and arthropod were dominant. The percentage of the species number in different functional groups to the total species ranked in the order of C>D>Pl>O>Ph, the percentage of the inhabited density showed the sequence of Pl>D>C>O>Ph, and the percentage of the biomass was Pl>C>D>O>Ph. The cluster analysis showed that there were three macrobenthos assemblages in the Bay. No significant differences were observed in the species number, inhabited density, and biomass  between seasons. The Marglef index (d) ranked in the order of C>D>Pl>O, and showed a significant difference between seasons (P<0.05). The Pielou’s index (J′) ranked in the order of C>D>O>Pl, and the Shannon  index (H′) was C>D>Pl>O, but no significant differences were observed between seasons.  There was a significant positive linear correlation between species diversity and functional group diversity. The ABC curve showed that the macrobenthic community was disturbed in different degrees. There were four trophic levels in the macrobenthic community and their food source, and the macrobenthic functional groups belonged to the Ⅱ, Ⅲ, and Ⅳ trophic levels. A complicated food web was composed between all the trophic levels.
    Metazoan zooplankton community structure and aquatic ecology of Daliaohe River, North China in summer.
    WANG Lu-lu1, DONG Fang1, LI Fang-fang1, DUAN Meng1, ZHU Lin1,2,3**
    2013, 32(2):  389-395. 
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    As a basic work for establishing China ecological criteria of water environment, an investigation was conducted on the metazoan zooplankton community structure and aquatic ecology in the Daliaohe River in June 2011, based on the relevant guidelines. A total of 59 metazoan zooplankton species were recorded, most of which  belonged to Rotifera, occupying 84.75% of the total. The total density of the metazoan zooplankton at different sampling sites varied from 8.63 to 2292.06 ind·L-1, with an average of 628.97 ind·L-1 and dominated by rotifers. At all sites, Brachionus and Keratella were the dominant species. A total of 28 species as water pollution indicators were detected, among which, 11 species  belonged to β-mesosaprobic species, occupying 40%. The Shannon index of the metazoan zooplankton community was 2.33-3.93, Margalef index was 2.84-9.42, and Pielou index was 0.59-0.97. Based on this investigation, it was considered that the Daliaohe River was in eutrophic situation and moderate pollution level. As compared with the previous data, the aquatic ecosystem situation of the River was somewhat improved.
    Phytoplankton community and its relationships with environmental factors in Dayang Port of Lüsi, Jiangsu Province of East China. 
    WU Jian-xin1,2**, LI Qiang3, ZHANG Qing3
    2013, 32(2):  396-400. 
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    In April 2010, an investigation was conducted on the phytoplankton’s species composition, diversity, abundance, and distribution at 20 stations in the coastal waters of Dayang Port in Lüsi. A total of 85 species belonging to 30 genera and 3 phyla were identified, including 81 species and 27 genera of Bacillariophyceae (accounting for 95.29% of the total species number), 3 species and 2 genera of Cyanophyta (accounting for 3.53%), and 1 species and 1 genus of Chrysophyta (accounting for 1.18%). As for the ecotype, most of the species were of lowsalt nearshore taxa, while eurythermic and euryhalic species were rarely appeared. The main dominant species were Skeletonema costatum, Coscinodiscus marginatus, Synedra fasciculate, Nitzschia longissima, C. excentricus, Thalassiosira rotula, C. lineatus, and C. radiatus, with the dominance index being 0.319, 0.308, 0.246, 0.243, 0.186, 0.131, 0.122 and 0.120, respectively. The abundance of the phytoplankton varied from 0.641×104 ind·L-1 to 3.136×104 ind·L-1, with an average of 1.640×104 ind·L-1. The amplitude of community character indices varied greatly (species number 23-42, richness index 0.603-1.339, Shannon index 2.362-3.840, and evenness index 0.638-0.958), indicating the instability of the community structure. The mean Shannon index of the phytoplankton was 3.327, mean richness index was 1.007, and mean evenness index was 0.859. The correlation analysis showed that the evenness index was significantly negatively correlated with the water Zn and Hg contents, COD, and DIN, and positively correlated with water salinity. There were also significant positive correlations between the richness index and the water As content and DO, and significant negative correlation between the diversity index and the water Zn content.
    Purification efficiency of four combinations of aquatic macrophytes on eutrophic water body in winter.
    WANG Xiu-fang1,2**, XU Kai-ping1, YE Sui-gao1, XUE Lin-lin3, LIU Gui-hua2, YOU Ai-ju1, SU Fei1
    2013, 32(2):  401-406. 
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    Ten species of low temperature-tolerant aquatic macrophytes were chosen to construct four combinations of aquatic macrophytes to study their purification efficiency on eutrophic water body in winter. In non-macrophyte treatment (CK), the removal efficiency of water total nitrogen (TN), nitrite nitrogen (NOx-N), ammonium nitrogen (NH4-N), and total phosphorus (TP) was 40.0%, 25.9%, 27.3%, and 64.5%, respectively. Combination 1 (Iris hexagonus Hybrid + Rumex japonicas + Acorus gramineus “Ogan” + Juncus inflexus “Blue Arrows”) grew luxuriantly in the test eutrophic water body, and performed best in decreasing water TN, NOx-N, NH4-N, and TP, with the removal efficiency being 47.8%, 52.2%, 32.4%, and 70.1%, respectively. Combination 2 (I. hexagonus Hybrid + R. japonicas + A. gramineus “Ogan” + Hemerocallis middendorfii) could survive and had definite growth amount in the test eutrophic water, and the removal efficiency of water TN, NOx-N, NH4-N, and TP was 44.2%, 58.5%, 34.6% and 67.8%, respectively. In contrast, both the combination 3 (R. japonicas + Lolium perenne + Chlorophytum comosum + Juncus pallidus R. Br. “Javelin”) and the combination 4 (R. japonicas + L. perenne + C. comosum + Carex tristachya) only had an obvious efficiency in removing NOx-N but less efficiency in removing TN, NH4-N, and TP, due to the poor growth of C. comosum and C. tristachya. It was suggested that combinations 1 and 2 had better purification efficiency on eutrophic water body, being the suitable combination forms of aquatic macrophytes floatingbed under low temperature in winter.
    Differences of periphytic algal community structure in different sections of Fanhe River, Liaoning Province of Northeast China.
    FU Bao-rong1, ZHANG Run-jie1**, LI Xia1, HUI Xiu-juan1, ZHANG Nan1, FU Hao1, ZHANG Zheng2, XIE Yi2
    2013, 32(2):  407-411. 
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    In dry and rainy seasons of 2011, an investigation was conducted on the species and density of periphytic algal communities in ten sections of Fanhe River located in northern Liaoning Province of Northeast China. A total of 47 genera, 25 families, 16 orders, 8 classes, and 6 phyla were identified, with 35 genera in dry season and 32 genera in rainy season. The periphytic algal communities in the River were mainly consisted of diatoms, followed by green algae and blue algae. The average density of the algae was 11.92×105 cell·cm-2 in dry season and 3.75×105 cell·cm-2 in rainy season. The dominant species in dry season were Synedra ulna, S. acus, Fragilaria brevistriata, F. capucina, Diatoma vulgare, Cymbella affinis, C. ventricosa, and C. cistula, and those in rainy season were Oscillatoria formosa, O. tenuis, Phormidium sp., Synedra ulna, Gomphonema acuminatum, and Cocconeis placentula. The evaluation with Shannon diversity index indicated that the water quality of the River was of slight pollution.
     
    Bryophyte species diversity and its indicative roles in monitoring heavy metals pollution in Zhangjiawanzi gold deposit area of Guizhou Province, Southwest China.
    ZUO Si-yi1, WANG Zhi-hui1, ZHANG Zhao-hui1,2**
    2013, 32(2):  412-417. 
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    An investigation was conducted on the bryophytes in Zhangjiawanzi gold deposit area of Guizhou Province, and the fluorescence spectroscopy (AF-640) and absorption spectrophotometer AAnalyst 800 were used to measure the concentrations of 6 heavy metals (Cu, Zu, Cd, Pb, Hg, and As) in the dominant bryophyte species and soils in heavily polluted area, relatively polluted area, and clean area. A total of 75 bryophyte samples were collected, belonging to 23 species, 16 genera, and 9 families. The dominant families were Pottiaceae and Bryaceae, whose life-forms were mainly of short turfs, tall turfs, wefts, and mats. The short turfs were significantly dominant, taking up 80.3% of the total life-forms. The measurement of the heavy metals concentrations indicated that this gold deposit area was heavily polluted by Hg, As, and Cd. The enrichment coefficient of Cd by Cymnostomum subrigidulum and Plagiomnium cuspidatum was 5.58 and 1.64, belonging to intensive and relative enrichment, respectively. The concentrations in the bryophytes and soils had a significant positive correlation, suggesting that bryophytes could be used for the monitoring of heavy metals pollution in this gold deposit area.
    Biodiversity impact assessment of mineral resources exploitation and conservation planning in Ganzi Prefecture of Sichuan Province, Southwest China.
    GENG Hai-qing1**, YANG Jiu-xian2, XIONG Wei3, WANG Hao4
    2013, 32(2):  418-424. 
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    In order to explore the impact of the exploitation and conservation planning of mineral resources on the local biological diversity, the Ganzi Prefecture of Sichuan Province was divided into 8 types of vegetation landscape, with the landscape density, frequency, proportion, and dominance in 2005 (the year before the planning implemented) calculated, and the variations of these indices in 2010 and 2020 (the years after the planning implemented) predicted. Through the overlapping of the planning areas and the biodiversity sensitive areas, their spatial conflicts were analyzed, and, based on the screening, integration, and synthesizing of the information from the vegetation maps in the upper reaches of Yangtze River, in combining with field survey, 40 vegetation types in the Prefecture were divided. The biomass distribution map of the vegetations in the Prefecture was drawn, and the biomass in each planning area was calculated. By using the distribution map of the fauna and flora in the Prefecture, the ratio of the grid of each species in each encouraged mining area and restrictive mining area to the total grids in whole planning area was calculated, and applied to denote the affecting extent of the mining activities on each species. Based on the above work, the adjustment proposals for the mineral resources exploitation and conservation planning in the Prefecture were raised.
    Influence of Ring Changbai Mountain Scenic Highway on wildlife.
    WANG Yun1**, PIAO Zheng-ji2, GUAN Lei1, KONG Ya-ping1
    2013, 32(2):  425-435. 
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    With the large-scale expansion of highway construction in ecologically sensitive area, wildlife conservation has become an urgent and important topic during the highway infrastructure construction and operation. However, few studies have been made on the wildlife conservation along the highways in China. By using sample line method and infrared camera monitoring, a field survey from November 2008 to February 2012 was conducted on the roadkill, road effect zone for wildlife, wildlife crossing highway, and wildlife crossing structure along the Ring Changbai Mountain Scenic Highway, which is adjacent to the Changbai Mountain Nature Reserve. The results showed that within the 500 m roadside of the Highway, the species richness of mammals, birds, reptiles, and amphibians accounted for 42.86%, 24.78%, 66.67%, and 66.67% of the wildlife species richness in the Nature Reserve, respectively. Among the wildlife, 11 species were national protective species, 2 of which were of firstclass, and 9 were of secondclass. A total of 3475 wildlife belonging to 59 species were killed by the vehicles on this Highway, and the road-kill rate was averagely 61.6 individuals·100 km-1. In terms of magnitude, amphibians had the highest mortality (2996 individuals). The species richness of birds and mammals was not impacted by the Highway, but there was a concentrative trend about the frequency of these wildlife activities within the 200 m roadside. The 10 surveys in winter indicated that a total of 13 species were found crossing the Highway for 502 times, and Siberian Weasel had the highest crossing frequency (169 times). When crossing the Highway, the wildlife preferred to the highway section with the roadside vegetation being primitive Korean pine and broad-leaved forest. There were 6 medium and large sizes species using bridges and culverts to cross the Highway, and the utilization rate of the bridges and culverts was 88% and 44.2%, respectively. Vegetation type, human disturbance, and size of wildlife crossing structure all had significant effects on the utilization rate. Some countermeasures for protecting the wildlife were provided correspondingly.
    Soil erosion evaluation and landscape pattern analysis of loess hilly gully area based on RUSLE-SMA: A case study of Caijiamiao watershed in Qingcheng, Gansu Province of Northwest China.
    PAN Jing-hu, WEN Yan**
    2013, 32(2):  436-444. 
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    By using a linear spectral mixture analysis (SMA) model, the vegetation coverage in the Caijiamiao watershed in Qingcheng County of Gansu was extracted from the Landsat TM images, and the factors affecting the vegetation coverage were obtained. With the help of the revised universal soil loss equation (RUSLE), the amount of the soil erosion in the watershed in 2003 and 2010 was estimated. The relationships between the soil erosion and the land-use type and topographic factors were analyzed, and the changes in the soil erosion landscape pattern were studied. In the 7 years from 2003 to 2010, the soil erosion amount in the watershed increased from 3.61×106 to 4.48×106 t·a-1, with an increment of 24%. The mean annual soil erosion intensity increased from 8590.23 t·km-2 to 10652.01 t·km-2. The soil erosion varied greatly with land use type, being more serious on unutilized land, grassland, and garden land, and on the areas with a slope greater than 15°, elevation below 1395 m, and aspect west. Overall, the erosion landscape in the study area was highly fragmented, the total number of patches reduced, fragmentation degree lowered, landscape heterogeneity decreased, and landscape shape tended to be regular. Except the slightly eroded landscapes, the landscape types tended to be simplified.
    Comprehensive evaluation on the evolution characteristics of artificial oasis in Sangong River Basin of Xinjiang, Northwest China.
    LIU Li-juan, WANG Yu-gang**, LI Xiao-yu
    2013, 32(2):  445-451. 
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    Taking the Fukang Oasis, Fubei Oasis, and the entire watershed agricultural oasis in Sangong River Basin of Xinjiang, Northwest China as the three evaluation units, the evolution characteristics of artificial oases in arid zone was comprehensively evaluated from the aspects of oasis landscape structure, vegetation construction, utilization degree of water resources, oasis productivity level, social and economic conditions, soil structure, emergy characters, and hydroengineering construction level. The factorial analysis showed that among the 42 second-level indices of artificial oasis maturity, there were two factors with the eigenvalues higher than 1, and the sum of the eigenvalues was 100% of the total variance, which can explain all variable information, and can be attributed to the hydro-engineering construction feature factors and societyeconomyproductivity factors. The maturity analysis showed that Fukang Oasis was a highly developed oasis, Fubei Oasis was a potentially developed oasis, and the entire oasis in Sangong River Basin was a weakly developed oasis.
    Landscape pattern changes of vegetation coverage in Loess Plateau of Northwest China in 2000-2011.
    ZHANG Jian-xiang, ZHANG Bo**, YIN Hai-xia, WANG Yuan-yuan, ZHAO Yi-fei
    2013, 32(2):  452-458. 
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    With the help of RS and GIS, and based on the remote sensing data of MODIS NDVI, this paper analyzed the landscape pattern changes of vegetation coverage in Loess Plateau in the time intervals 2000-2003, 2004-2007, and 2008-2011 and in the each period of summer (early summer, mid summer and late summer). In the past twelve years, the vegetation coverage in the Plateau at landscape level had a great change. The fragmentation and complexity decreased after an initial increase in early summer, but tended to be complicated in mid summer and late summer, i.e., the landscape dominance and the aggregation of the largest patch decreased, the diversity decreased after an initial increase, whereas the landscape connectivity had less change. At coverage type level, the interannual change was mainly manifested in the conversion from medium-low and medium coverage types to mediumhigh and high coverage types, while the low coverage type had a trend of increased first and decreased then, with a small change range of about 3% to 5%. In terms of intra-seasonal variability, the low coverage type continued to decrease, the medium and high coverage types increased obviously, with the maximum increment being 9.76%, the mediumlow coverage type had the largest decrement (13.77%) in midsummer, while the other coverage types had no clear variation trend. The results revealed the landscape pattern changes of vegetation coverage in the Loess Plateau of Northwest China, which could provide references for the construction of local vegetation and the protection of local ecological environment.
    Effects of spatial grain change on the landscape pattern indices in Yimeng Mountain area of Shandong Province, East China.
    ZHANG Ling-ling1, SHI Yun-fei1**, LIU Yu-hua2
    2013, 32(2):  459-464. 
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    Based on the graphs of soil erosion intensity at different spatial scopes in Yimeng Mountain area in 2004, and by using GIS technology and Fragstats software, 8 landscape pattern indices were selected to study the effects of the grain size of landscape pattern indices at different spatial scopes within the range of 20 to 65 m in Yimeng Mountain area, and the functional fitting analysis was applied to analyze the landscape pattern indices. With the increase of grain size, the landscape pattern indices showed different change trends, i.e., rising, declining, or unconspicuous change. As for the two study areas with different spatial scopes, the first scale domain of landscape pattern index was (20, 35), and the optimal spatial grain sizes were all 35 m. Through the fitting of the selected 8 landscape pattern indices by one-dimensional linear regression analysis, it was found that the NP, PD, LSI, PAFRAC, CONTAG, and AI could fit the change trends of the indices well, while the fitting results of LPI and SHDI were unsatisfactory.
    Correlations between road density and settlement percentage coverage in Jiangsu Province, East China.
    ZHANG Qing-qing1, LIU Mao-song1**, XU Chi1, ZHANG Ming-juan2, ZHANG Yan1
    2013, 32(2):  465-472. 
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    Based on the 1∶10000 topographic map of Jiangsu Province in 2000, and by the method of neighborhood statistics, this paper analyzed the spatial distribution characteristics of road density (RD) and settlement percentage coverage (SPC) in 15 counties of Jiangsu Province at the scales of 5, 10, 15, and 20 km, with the correlation degrees of RD and SPC at 16 scale pairs of each county compared. The results showed that road was a kind of the landscape element with low heterogeneity, while settlement was a kind of the landscape element with high heterogeneity. The spatial heterogeneity of road and settlement all decreased with increasing scale, but the decreased degree of the spatial heterogeneity of road was less obvious than that of the spatial heterogeneity of settlement. In the areas with higher RD or SPC, the spatial heterogeneity of road and settlement tended to be lower. At the 16 scale pairs, the correlation degree of RD at 20km scale and of SPC at 5km scale was the highest, and the RD at 20km scale showed a ladder-like growth with the increase of SPC at 5km scale, presenting a discontinuous growth. Due to the differences in the scaledependent attributes between RD and SPC, it would be necessary to compare the correlation degrees of these two elements under different scale-pairs, and select the appropriate scale combinations to study the correlations between landscape elements under different scale-pairs.
    Effects of nitrogen deposition on peatland: A review.
    ZENG Jing1, BU Zhao-jun1**, WANG Meng2, MA Jin-ze1, ZHAO Hong-yan1, LI Hong-kai1, WANG Sheng-zhong1
    2013, 32(2):  473-481. 
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    Peatland is an important carbon pool in global carbon cycle. Its oligotrophic environment, ecological processes, and ecological functions are affected by nitrogen deposition. This paper reviewed the effects of nitrogen deposition on peatland ecosystems from the following aspects: (1) the production in peatland is generally nitrogen-limited, while nitrogen deposition can change the peatland soil environment by increasing nitrogen availability, altering microbial composition, increasing bacterial quantity, and improving enzyme activity; (2) in high nitrogen deposition peatland, the nitrogen interception, translocation, and tolerance abilities of Sphagnum- will be decreased, leading to the toxic effect on Sphagnum and its replacement by nitrophilous vascular plants; (3) nitrogen deposition may change the oligotrophic soil environment, and promote the productivity of peatland; (4) the increase of nitrogen supply may improve the growth of vascular plants, leading to the inferior position of Sphagnum in light competition and the alternation of interspecific relationships between Sphagnum and vascular plants; (5) nitrogen deposition will change the N/P ratio in plants, and then, affect the reproduction and regeneration of Sphagnum, which will bring about the changes of vegetation species composition, and therefore, vegetation succession in peatland; and (6) through the interaction of above and belowground biological components, nitrogen deposition will accelerate peat decomposition, and weaken the role of peatland as a carbon pool. Some issues in the present related studies were addressed, and some suggestions for the further researches were offered.
    Effects of air temperature during rice grain-filling period on the formation of rice grain yield and its quality.
    GONG Jin-long, ZHANG Hong-cheng**, HU Ya-jie, LONG Hou-yuan, CHANG Yong, WANG Yan, XING Zhi-peng, HUO Zhong-yang
    2013, 32(2):  482-491. 
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    The grain-filling period of rice is critical to the formation of rice grain yield and its quality, whereas the air temperature in this period has significant effects on the rice grain-filling. With the global warming and the increasing frequency and amplitude of extreme temperature
    events, to study the response characteristics of rice grain-filling and grain quality to temperature stress and the related physiological and biochemical mechanisms is one of the research hotspots in rice cultivation. Taking the air temperature during rice grain-filling as the cutin point, this paper discussed the appropriate temperature for the formation of rice grain yield and its quality, the critical period affected by temperature, and the physiological and biochemical characteristics of rice under temperature stress. The key stage the temperature affected the rice grain yield and its quality was the early period of grain-filling (20 days after full heading). The optimum temperature, 21-26 ℃, was conducive to the enrichment and deposition of starch in rice grain, while too high or too low temperature was unbeneficial to the grain yield and its quality. Under temperature stress, the physiological and biochemical activities of rice decreased, its photosynthetic functions declined, resistance to adversity lowered, and dry matter accumulation and translocation were restrained, resulting in the decline of rice production and the deterioration of rice grain quality. These findings could provide reference for the rice cultivation of high yield and high quality  and the research of the temperature in rice grain-filling period.
    Urban non-point source pollution: Research progress.
    LI Chun-lin1,2, HU Yuan-man1, LIU Miao1**, XU Yan-yan1,2, SUN Feng-yun1,2
    2013, 32(2):  492-500. 
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    Urban non-point pollution is a new issue appeared with rapid urbanization, which mainly comes from city industrial emission, fossil fuel burning, vehicle exhaust, and soil erosion, etc., and seriously endangers the safety of urban water quality and ecosystem through the flush of storm runoff into urban waters. This paper elucidated the connotations of urban nonpoint pollution, its formation process, and affecting factors, introduced the research methods of urban storm runoff, including event mean concentration (EMC) and first flush (FF), and the research progress of two non-point source pollution models (SWMM and HSPF), and summarized the applications of best management practices (BMPs) and low impact development (LID) in controlling urban non-point pollution. In view of the shortages of current related studies, it was proposed that on the basis of strengthening the researches of pollutant movement mechanisms, the urban nonpoint source models should be further improved, and the suitable urban non-point pollution management practices should be developed, in combining with urban planning and landscape design.
    Effects of cryopreservation by vitrification on the viability of eelgrass Zostera marina seeds.
    ZHANG Ling-yu, ZHANG Pei-dong**, TIAN Lu, SUN Yan, ZHANG Xiu-mei
    2013, 32(2):  501-506. 
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    In this paper, three key factors of cryopreservation by vitrification, i.e., cryoprotective solution application, dehydration time of vitrification solution, and rapid freezing, were installed to study the effects of cryopreservation by vitrification on the viability of Zostera marina seeds. Cryoprotective solution application and dehydration time had no significant effects on the viability of the seeds. When exposed to rapid freezing, the viability of the seeds was significantly lower than that of the control, while cryoprotective solution application and dehydration time showed no significant protective effects on the viability of the seeds. Without cryoprotective solution application, the viability of the seeds subjected to 4 h dehydration was significantly lower than that of the seeds subjected to other lengths of dehydration time. With cryoprotective solution application, no significant difference was found between the viability of the seeds subjected to 4 h dehydration and that of the seeds subjected to other lengths of dehydration time. These findings indicated the necessity of cryoprotective solution application to seeds prior to the long period dehydration by vitrification. This study provides a reference for the cryopreservation of Z. marina seeds.
    Efficiency of multimesh gillnets and multi-mesh trammel nets in collecting fish from rocky reef and sandy beach habitats.
    WANG Zhen-hua, GONG Fu-xian, WU Zu-li, BI Yuan-xin, ZHANG Shou-yu**
    2013, 32(2):  507-514. 
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    In order to fully understand the efficiency of multi-mesh gillnets (MGN) and multi-mesh trammel nets (MTN) in collecting fish from soft bottom and hard bottom habitats, a 5day trial in the sandy beach (SB) and rocky reef (RR) habitats around Gouqi Island of East China was conducted in October 2011. The fish collection efficiency of MGN and MTN in SB and RR was compared from the viewpoints of fish composition, fish collection way, dominant fish composition and their relative abundance, and fish diversity indices and community patterns. The fish species collected by MTN were five more in SB and eight more in RR, as compared with those collected by MGN. In SB, the dominant fish species collected by MGN were Sardinella zunasi and Larimichthys polyactis, while those collected by MTN were S. zunasi, L. polyactis, and Paraplagusia japonica; in RR, only Sebastiscus marmoratus and Hexagrammos agrammus were the dominant fish species collected by MTN, while two more dominant fish species, i.e., Sardinella zunasi and L. polyactis, were collected by MGN. The fish collection ways of MTN and MGN differed. Most of the individuals collected by MGN both in SB and in RR were wedged, and only a small part of the individuals were gilled and entangled, whereas the percentages of gilled, entangled, and some other combined ways collected by MTN in the two habitats were increased significantly. In SB, the catch rates of S. zunasi and L. polyactis by MGN were significantly higher than those by MTN, while that of P. japonica was in contrary; in RR, MTN had higher catch rates of S. marmoratus and H. agrammus, while MGN indicated significantly higher catch rates than MTN. There were significant differences in the species diversity indices between the samples collected by MGN and MTN in SB, but no significant differences in RR. The cluster and ordination based on the abundance data indicated the significant differences in the fish community structure between MGN and MTN both in SB and in RR. It was suggested that when collecting fish with gillnets, it needed to design suitable nets and methods to get comprehensive information on the real fish assemblages.