Table of Content

08 June 2011, Volume 30 Issue 06

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Articles

Effects of elevated temperature on CO₂ flux during growth season in an alpine meadow ecosystem of Qinghai-Tibet Plateau.

2011, 30(06):  1045-1051. 

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Two open-top chambers (OTCs) with height 0.4 m (OTC-1) and 0.8 m (OTC-2) were used to simulate the global warming and to study the effects of elevated temperature on the CO₂ flux during growth season in an alpine meadow ecosystem in Qinghai-Tibetan Plateau. The OTC-1 and OTC-2 had an increased mean annual temperature 1.25℃ and 3.68℃, respectively, compared with the control. In the control, OTC-1 and OTC-2, the CO₂ fluxes all showed an evident seasonal variation, and peaked at vigorous growth stage (from July to August), being 2.31, 2.35, and 6.38 μmol·m^-2·s^-1, respectively. At different growth stages, the CO₂ fluxes all showed an increasing trend with the increment of temperature, indicating that global warming could cause the increase of CO₂ flux in alpine meadow. The CO₂ fluxes in the control, OTC-1 and OTC-2 all had significant correlations with air temperature and the soil temperature and moisture at the depth of 5 cm. The correlations between the CO₂ emission fluxes and the air temperature and soil temperature were exponential, and those between the CO₂ emission fluxes and soil moisture were quadric multinomial.

Grazing-tolerance of two major plant species in alpine Kobresia humilis meadow.

2011, 30(06):  1052-1062. 

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A field manipulation experiment was conducted to study the effects of clipping (stubbled 3 cm, stubbled 1 cm, and unclipped), fertilizing (fertilized and non-fertilized), and watering (watered and non-watered) on the compensatory height (CH), relative height growth rate (RGR), specific leaf area (SLA), net photosynthesis rate (NPR), and total aboveground biomass per ramet (TAB) of two major plant species (Kobresia humilis and Elymus nutans) in an alpine K. humilis meadow, aimed to compare the grazing-tolerance of the two species, and to analyze the relationships between the tolerance and the resource availability of soil. The CH and TAB of the two species had an under-compensatory response to clipping, while the RGR increased significantly with clipped intensity and the clipped effect was accumulative over time. The responses of SLA, NPR, and TAB to clipping were more sensitive for E. nutans than for K. humilis. Though fertilization greatly improved the test indices of the two species, the grazing-tolerance index of K. humilis under fertilized and non-fertilized conditions was smaller than that of E. nutans. Watering had little effects on the tolerance index of the two species. It was suggested that the grazing-tolerance of the two species depended on the resource availability of soil to some extent, and K. humilis had a higher tolerance ability than E. nutans.

Spatial distribution patterns of vegetations on natural grassland in Loess Plateau interfluve.

2011, 30(06):  1063-1069. 

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Taking the hill top in semi-arid hilly region of Loess Plateau in North Shaanxi as the object, an investigation was conducted on the herb vegetations in 31 quadrats with an interval of 40 m, and the methods of classic statistics and geostatistics were adopted to analyze the spatial distribution patterns of the vegetations on natural grassland in Loess Plateau interfluve. The linear correlation analysis and rank correlation analysis indicated that slope position was
the main factor affecting the herb coverage and dry/wet mass ratio, slope aspect was the main factor affecting the herb average height and biomass, while slope gradient had no significant effects on the spatial distribution of the herb species. The spatial correlation analysis with Moran’s I index indicated that the herb coverage, average height, and dry/wet mass ratio had positive spatial correlations within 60 m lag distance, and the herb biomass had a significant spatial correlation within 180 m lag distance. The experimental semivariation of herb average height and biomass could be well fitted with spherical model, and that of herb dry/wet mass ratio could be well fitted with Gaussian model, the autocorrelation range values of the three herb parameters being 99.3 m, 66.6 m, and 78.4 m, respectively, showing a strong spatial autocorrelation. The experimental semivariation of herb coverage could be fitted with linear model.

Responses of vegetation productivity in Horqin Sand Land to simulated increased precipitation and nitrogen deposition.

2011, 30(06):  1070-1074. 

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By using precipitation collection device and with ground surface nitrogen application, a randomized block design was adopted to study the effects of simulated increased precipitation and nitrogen deposition on the vegetation productivity of typical Caragana microphylla community in Horqin Sand Land. When the precipitation increased by 1/7, the mean vegetation height had no significant increase, but the vegetation biomass increased by 17.6%. When the precipitation increased by 2/7, the mean vegetation height increased by 23%, and the vegetation biomass increased by 31.8%. One-year nitrogen deposition had no significant effects on vegetation biomass. Therefore, precipitation could be the key factor affecting the vegetation productivity on sandy land. The vegetation productivity had a rapid response to increased precipitation, while short-term increased nitrogen deposition had little effects on the vegetation productivity.

Effects of ozone stress on diurnal change of winter wheat photosynthesis at milking stage.

2011, 30(06):  1075-1082. 

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By using open top chamber, a field experiment was conducted to study the effects of elevated ozone concentration on the diurnal change of winter wheat photosynthesis at milking stage. At 13:00-15:00, the field environmental variables (photosynthetic active radiation, chamber temperature, and vapor pressure difference) were the menace to the winter wheat photosynthesis. Comparing with the control, fumigation with 100 and 150 nl·L^-1 of ozone led to the decrease of net photosynthetic rate by 6.3% and 11.1%, respectively (P<0.05). In treatment 100 nl·L^-1 of ozone, the stoma limit value, transpiration rate, stomatal conductance, and water use efficiency had a change trend basically in accordance with that in control; whereas in treatment 150 nl·L^-1 of ozone, the transpiration rate and stomatal conductance increased significantly before 11:00, but the water use efficiency was in adverse. At 13:00-15:00, the water use efficiency increased significantly in both cases. The above evidences indicated that under no environmental stress, the decrease of net photosynthetic rate could be attributed to the stomatal and non-stomatal limitation in treatments 100 and 150 nl·L^-1 of ozone, respectively. Under stressed environment, both 100 and 150 nl·L^-1 of ozone improved the winter wheat water use efficiency significantly, moreover, 150 nl·L^-1 of ozone induced a significant increase of intercellular CO₂ use efficiency.

Plant and soil organic carbon pools in a constructed wetland of Shatianhu River.

2011, 30(06):  1083-1090. 

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The artificially constructed wetland of Shatianhu River is a complex wetland system used for treating the surface flow and horizontal undercurrent of aquaculture wastewater. Taking this wetland as test object, this paper studied the seasonal variations of organic carbon concentration in plant organs, surface soil (0-10 cm), and rhizosphere soil, and assessed the carbon sequestration potential of the plant organs and surface soil. The fixed carbon in the aboveground parts of the wetland plants increased rapidly during growth period, being higher in August and kept stable at mature stage (November), and with significant difference between May and August and but less difference between August and November. The carbon fixed in underground parts of the plants was lower than that in aboveground parts, but its seasonal variation pattern was similar, being the lowest in May, relatively higher in August, and less difference between August and November. During the growth period of the plants, surface soil organic carbon content was significantly higher than that in the period with no plants in the wetland. The organic carbon content in surface soil was lower than that in rhizosphere soil, but less difference was observed (except for water lily). The surface soil organic carbon density was in the range of 0.96-1.67 kg·m^-2, which was affected by the plant species, plant growth season, and others. Based on the wetland area (surface flow part was 3592 m²) and surface soil organic carbon content, it was estimated that the wetland surface soil organic carbon stock was 5.61 t, and the annual plant carbon sequestration was 10.34 t.

Effects of different cutting regimes on the productivity of Ipomoea aquatica Forsk planted on floating-mats in a eutrophicated river of Shanghai.

2011, 30(06):  1091-1099. 

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This paper studied the effects of different combinations of cutting frequency (once every 14, 21, and 28 days) and stubble-remaining height (15, 25 and 35 cm) on the output of Ipomoea aquatica Forsk planted on floating-mats in a eutrophicated river of Shanghai. After cutting, the plants could still grow healthily during its whole lifecycle. The tiller number after 110 d growth was 5 times of the control, with the longest root length, average root length, and average root system diameter being 27.55 cm, 11 cm, and 15 cm, respectively. The fresh root biomass per plant was 146 g, and the roots per square meter floating mat could adsorb 3.36 kg suspended particulates. With increasing cutting frequency, the sprout growth rate had a trend of increasing first and decreased then, and the variation range was 0.54-3.7 cm·d^-1, compared with 1.63 cm·d^-1 of the control (no-cutting). Appropriate cutting could promote sprout growth rate. The biomass harvested per unit time had the similar variation trend as sprout growth, and the biomass growth rate was 3.83-37.9 g·m^-2·d^-1. The dry biomass output was the highest (2112 g·m^-2) in treatments cutting every 28 days and stubble-remaining height at 25 cm and 35 cm, and the stem/leaf ratio was higher in treatments cutting every 14 days and stubble-remaining height at 15, 25, and 35 cm, and cutting every 21 days and stubble-remaining height at 15 cm and 25 cm. To comprehensively consider the biomass output and quality as well as the management convenience of floating-mats, cutting every 21 days and stubble-remaining height at 15 cm was the best cutting regime, under which, the average sprout growth rate was 1.88 cm·d^-1, stem/leaf ratio was less than 1, and total biomass was 1966 g·m^-2.

Buildup and environmental effect of clean mariculture model in land-based enclosure.

2011, 30(06):  1100-1106. 

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By the method of land-based enclosure, three kind organisms including fish (Sparus macrocephlus), seaweed (Gracilaria lichevoides), and benthos (Perinereis aibuhitensis) were selected to construct four kinds of mariculture models, i.e., S. macrocephlus (F), S. macrocephlus + G. lichevoides (FG), S. macrocephlus + P. aibuhitensis (FP), and S. macrocephlus + G. lichevoide + P. aibuhitensis (FGP) to study the removal of nitrogen (N), phosphorus (P), and particulate organic matter (POM) in water body and sediment, and to analyze the environmental effect of each mariculture model, aimed to approach a clean mariculture model in land-based enclosure. Among the four mariculture models, culturing fish with 1.5 kg·m^-2 of seaweed and 22.5 kg·hm^-2 of benthos had better effects in purifying water body and sediment, and effectively increased the harvested fish yield. The seaweed could effectively remove the dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) in water body. The models with seaweed had significantly lower concentrations of N and P in water bodies, compared with the models without seaweed (P<0.05), but no significant differences were observed between treatments FG and FGP and between F and FP. The benthos could remove the POM in the sediment, and the models with benthos had lower concentrations of N and P in the sediment. Especially in the sediment layers 1-2 cm and 2-4 cm, the N and P concentrations in the models with benthos were 7% and 9% lower than those in the models without benthos, respectively (P<0.05). Furthermore, the models with seaweed or/and benthos had higher fish yield, compared with fish monoculture model (P<0.05), and the fish yield in treatment FGP was 57% higher than that in treatment F. To have an integrative consideration, culture model FGP had the optimal environmental, economic, and comprehensive benefits.

Soil nitrogen and phosphorus downward translocation and vegetable nitrate and nitrite accumulation under effects of different rotation regime.

2011, 30(06):  1107-1113. 

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In 2009, a field experiment was conducted at the demonstration base of vegetable production in Damintun town of Shenyang City, Liaoning Province to study the effects of different rotation regime on the reduction of soil nitrogen and phosphorus downward translocation and of vegetable nitrate and nitrite accumulation. After one year planting, as compared with background values, the soil pH decreased by 0.09-0.47, surface soil total phosphorus (TP) content increased significantly, surface soil available phosphorus (AP) content was 86.80-161.04 mg·kg^-1, being significantly higher than the warning index (60 mg·kg^-1), and soil nitrate content was rather high, with an obvious downward translocation. Under the test three rotation regimes, the planted vegetables except spinach had the nitrate and nitrite concentrations accorded with the National safety standards for green vegetables. Among the rotation regimes tested, rape-cucumber-cowpea had the smallest variation range of soil pH, weaker downward translocation of soil nitrate, and higher nitrogen and phosphorous recovery, but less effect on the reduction of soil phosphorous downward translocation and of vegetable nitrate and nitrite accumulation. It was suggested that appropriate management practices should be taken to prevent the acidification, phosphorus accumulation, and nitrate downward translocation of facility vegetable soils.

Soil phosphorus sorption-desorption characteristics under different land use in Quanzhou City, Fujian.

2011, 30(06):  1114-1118. 

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Soil samples were collected from the rotation land, grassland, forestland, and dry land in Quanzhou City to study the soil phosphorus (P) sorption-desorption characteristics under different land use. Langmuir isotherm equation could well describe the soil P sorption characteristics. The soil P sorption capacity of rotation land and dryland was higher than that of grassland and forestland, and the soil P loss risk was in the order of rotation land > grassland > forestland > dry land. The soil P sorption constant and maximum buffering capacity were in the sequence of dry land > rotation land > forestland > grassland, and thereby, the recommended P application rate should be in accordance with the sequence. The soil P desorption rate of rotation land and grassland was higher than that of dry land and forestland, and the soil P buffering capacity was dry land > forestland > rotation land > grassland. Principal component analysis revealed that the mean P desorption rate, easily desorbable P, P sorption index, and equilibrium P concentration could best reflect the potential of soil P loss, and be used as the main indices to assess the potential of soil P loss.

Variation characteristics of soil active organic carbon along a soil moisture gradient in a riparian zone of Taihu Lake.

2011, 30(06):  1119-1124. 

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Soil carbon cycle in aquatic-terrestrial ecotone (e.g., riparian zone) is an important component of global carbon cycle, but few researches are made on it. Taking a typical riparian zone of Taihu Lake near Suzhou as the object, three experimental sites along a soil moisture gradient, i.e., from the near of water body to the high mound, were installed in this paper, with the soil water soluble organic carbon (WSOC) and light fraction organic carbon (LFOC) contents and their correlations with soil physical and chemical factors analyzed. Soil moisture had obvious effects on the surface soil (0-10 cm) active organic carbon. The surface soil WSOC and LFOC contents decreased along the soil moisture gradient, but the variation degree of these contents in deeper soil layers became smaller. The WSOC and LFOC contents were significantly higher in surface soil than in subsurface soil, which was in accordance with the variation trends of soil organic carbon and nitrogen. In different soil layers at each site, the WSOC and LFOC were all significantly positively correlated with soil total organic carbon, total nitrogen, and moisture, suggesting that the latter three parameters could be the main factors controlling soil active soil organic carbon.

Dynamics and degradation approach of different domestic animal feces chloroteracy-line in soil.

2011, 30(06):  1125-1130. 

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A simulated indoor incubation experiment was conducted to study the concentration dynamics and degradation approaches of different domestic animal feces chloroteracy-line (CTC) in soil. The degradation of the CTC in soil presented L-type curve, but the degradation rate and degradation percentage varied with feces kind and its dosage (P<0.05). On the 180th day of incubation, the CTC degradation percentage of chicken feces was lower than that of pig feces. In the treatments with low dosage chicken and pig feces, the degradation percentage was the highest, reached to 854% and 923%, respectively. The CTC degradation percentage was negatively correlated with the dosage of the feces, and positively correlated with incubation time. In the process of CTC degradation, exogenous microbes played most important role, accounting for 757%, while photo-degradation and chemo-degradation only accounted for a small portion. With the extension of incubation time, microbial and chemical degradation increased, while photo-degradation decreased. Our results suggested that the CTC concentration in domestic animal feces declined with self-decomposition and microbial degradation, etc., but could bring short-term environmental risk.

Spatial pattern of song sharing within Emberiza godlewskii population.

2011, 30(06):  1131-1136. 

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An in situ recording was conducted to study the spatial pattern of song sharing within Emberiza godlewskii population. A total of 24 individuals’ songs were recorded, averagely 34 songs each individual. Each song consisted of multi-elements, and the elements were grouped by shape and classified into seven broad categories. The song dissimilarity index was computed for each pair of the individuals, according to the usage of each element category. No significant differences were observed in the song dissimilarity index between neighbors (0.224±0.076) and non-neighbors (0.245±0.050) (T test, P=0.095), and also, there was no significant correlation between the song dissimilarity index and spatial distance (Mantel test, P=0.227). The song sharing within E. godlewskii population had no definite spatial pattern, possibly due to the excessive human disturbance on the habitat and the greater annual change of the individuals within the population.

Illex argentinus resource abundance and its relations to the main ecological factors in Southwest Atlantic Ocean.

2011, 30(06):  1137-1141. 

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Based on the 2000-2008 squid jigger (Illex argentinus) catch data of Chinese vessels in Southwest Atlantic Ocean and the related environmental information derived from satellites, this paper analyzed the recent 9 years change of I. argentinus resource abundance and its relations to the main ecological factors sea surface temperature (SST) and chlorophyll-a concentration (Chl-a)  in the Ocean. In the recent 9 years, the mean annual I. argentinus resource abundance in the Ocean changed greatly, with a turning point in 2004, i.e., decreased before 2004 and increased after 2004. In the nine years from 2000 to 2008, the SST and Chl-a  in the Ocean had definite correlations with the changes of the I. argentinus resource abundance. In 2000-2003, the annual SST had a larger fluctuation while the mean annual I. argentinus resource abundance was relatively constant, no obvious correlations between them. From 2004 to 2008, there existed a negative correlation between the resource abundance and SST. In 2000-2004, the I. argentinus resource abundance had no obvious correlation with the Chl-a . From 2005 to 2008, a positive correlation was observed between the resource abundance and the Chl-a.

Spatiotemporal distribution pattern of Chilean jack mackerel (Trachurus murphyi) fishing grounds and catch yield per unit effort in Southeast Pacific Ocean.

2011, 30(06):  1142-1146. 

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Based on the statistical data of Chilean jack mackerel catch yield of “Kai Fu” vessel in March-December 2007 and the related sea surface temperature (SST) obtained by satellite remote sensing, this paper analyzed the seasonal changes of fish catch and net catch, and approached the relationship between the spatiotemporal distribution pattern of Chilean jack mackerel catch yield per unit effort (CPUE) and SST. The CPUE was higher in May-August and lower in other months, being in the order winter > autumn > spring > early summer. In the whole year, the catch yield of Chilean jack mackerel was higher when the SST was at 12 ℃-14 ℃, followed by at 15 ℃-17 ℃. The fishing grounds were distributed in higher altitudes (41°S-46°S) in autumn, and moved northward (34°S-42°S) and westward to 101°W in winter, continuously westward and then eastward (29° variation of longitude) in early spring, and southward in early summer. Overall, in 2007, there was an obvious seasonal change in the spatiotemporal distribution patterns of Chilean jack mackerel fishing grounds, and the CPUE value had a larger fluctuation range.

Acute toxic effect of calcium cyanamide on golden apple snail (Pomacea canaliculata).

2011, 30(06):  1147-1152. 

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Golden apple snail (Pomacea canaliculata) is one of the 100 worst invasive alien species cognized by World Conservation Union, and has been resulting in a mass loss of rice production in South China. In this study, the snails accoding to their shell height (H) were divided into four groups, i.e., small size (5 mm≤H<15 mm), medium size (15 mm≤H<25 mm), large size (25 mm≤H<35 mm), and extra large size (35 mm≤H<45 mm), and a laboratory toxicity test was conducted to evaluate the molluscicidal activity of chemical fertilizer calcium cyanamide (CaCN₂) in controlling different sizes P. canaliculata. Calcium cyanamide had significant molluscicidal effect on different sizes, especially small and medium sizes P. canaliculata. After treated one week, 0.2 g·L^-1 of CaCN₂ induced 71% mortality, and high concentrations CaCN₂ resulted in above 95% mortality, with 100% mortality in treatments 3.0 g·L^-1 and 5.0 g·L^-1 of CaCN₂. Both the 24 h median inhibitive concentration and the 96 h median lethal concentration of CaCN₂ on different sizes P. canaliculata were all in the order of small size < medium size < large size < extra large size. Calcium cyanamide had significant inhibitive effect on P. canaliculata. The mean inhibitive concentration of CaCN₂ ranged from 0.08 g·L^-1 to 0.39 g·L^-1. After treated 24 h, the SOD activity of P. canaliculata in treatments 1.0 g·L^-1 and 5.0 g·L^-1 of CaCN₂ decreased significantly, being 41% and 60% of the control, respectively. This study showed that calcium cyanamide had definite potential in controlling P. canaliculata invasion, being hopeful to be used as a kind of molluscicidal fertilizer in paddy field.

Soil meso-micro faunal diversity in different restoration types of forest ecosystems in Miyaluo, West Sichuan.

2011, 30(06):  1153-1162. 

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To understand the soil meso-micro faunal diversity in different restoration types of forest ecosystems in West Sichuan, an investigation was conducted on the soil meso-micro fauna in the secondary Betula alba-sinensis forest (BSF), secondary Abies fabric forest (AFF), and Picea asperata plantation (PAP) in Miyaluo forest area in November 2008. A total of 15234 individuals of soil meso-micro fauna were collected, belonging to 3 phyla, 9 classes, 10 orders, 97 families, and 144 groups. The individuals of Nematoda accounted for 71.85% of the total, and those of Collembola, Acarina, and other groups took up 13.16%, 9.49%, and 0.36%, respectively. The group number and the individuals density of the soil fauna in the three forests followed the sequence of BSF > AFF > PAP. The Shannon index was in the order of BSF > AFF = PAP, Margalef index and density-group index were BSF > AFF > PAP, Pielou index was PAP > BSF > AFF, and Simpson index was AFF > BSF = PAP. No significant differences were observed in the individuals density among the three forests (P>0.05), but the Sοrenson index indicated that the taxonomic composition and community structure of soil meso-micro fauna in PAP differed to those in BSF and AFF. The vertical distribution of soil faunal taxa and individuals was more even in BSF than in PAP and AFF. All the results suggested that comparing with P. asperata plantation and secondary A. fabric forest, secondary B. alba-sinensis forest could more effectively improve soil faunal diversity, and promote the restoration of belowground ecological function more quickly.

Effects of arbuscular mycorrhizal fungi colonization on Bt corn growth.

2011, 30(06):  1163-1168. 

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Taking two Bt-corns 5422Bt1 (Bt11) and 5422CBCL (Mon810) that express Cry1Ab and their near-isogenic non-Bt corn (5422) as test materials, this paper studied the effects of inoculating G. mosseae  on their growth. There was an obvious difference in the colonization rate of G. mosseae on the three corn varieties, and the general trend was 5422Bt1 > 5422CBCL > 5422. Inoculating G. mosseae promoted corn growth, and the effect varied with corn variety and its development stage. For variety 5422, its aboveground biomass and total dry weight at bell stage increased significantly; for variety 5422Btl, its leaf number and stem diameter at jointing stage and its leaf number, stem diameter, aboveground biomass, and total dry weight at bell stage were significantly higher than those of the control; and for variety 5422CBCL, its leaf number at jointing stage and its underground biomass at bell stage also increased significantly. The AMF-dependence and the AMF-inoculation effect on the three corn varieties were in the order of 5422Bt1 > 5422CBCL > 5422, suggesting that the two Bt-corns had better compatibility with G. mosseae. Compared with non Bt-corn, Bt-corn had stronger positive responses in its growth to the AMF inoculation.

Microbial diversity and nitrification potential of sloping land red soil under different land use patterns.

2011, 30(06):  1169-1176. 

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Soil microbial community plays a crucial role in ecological sustainability in response to different land use patterns. In this paper, soil samples were collected from the cropland, naturally restored forestland, and tea garden on the red soil sloping land at the Taoyuan Agro-ecosystem Research Station (110°
72″E, 28°52″N) under Chinese Academy of Sciences to study the effects of different land use patterns on the soil microbial diversity and nitrification potent
ial. T-RFLP technique was adopted to study the diversity of bacteria, ammonia-oxidizing bacteria (AOB), and ammonia-oxidizing archaea (AOA), and aerobic culture method was used to study the nitrification potential. Under the three land use patterns, the diversity index of soil bacteria, AOB, and AOA showed the same variation trend, i.e., cropland = tea garden > naturally restored forest land (P<0.05). RDA analysis showed that the variations of soil physical and chemical properties under different land use patterns determined the community structure of soil AOB and AOA. Cropland soil had the highest nitrification potential, followed by tea garden soil, and naturally restored forestland soil. There was a significant positive correlation between the diversity index of soil bacteria, AOB, and AOA and the soil potential nitrification rate, especially for AOA, suggesting that AOA might play an important role in red soil nitrification.

Wild economic macro-fungi in Bijie District of Guizhou Province, Southwest China.

2011, 30(06):  1177-1184. 

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A field investigation on the wild economic macro-fungi was conducted at 14 locations in the Bijie District of Guizhou Province. A total of 437 fungal specimen
s were collected and identified, with 100 species (varieties and forms) of 52 genera and 31 families newly discovered, and 187 species of 86 genera of 44 families retraced from literatures. Family Russulaceae had the largest species number (34), occupying 18.2% of the total, followed by Polyporaceae (17 species and 9.1%), and Agaricaceae (14 species and 7.5%) and Boletaceae (14 species and 7.5%). Among the economic fungi, 141 taxa were edible, and 46 taxa were medical. Ectomycorrhizal fungi reached 96 species, occupying 51.3% of the total, and the rests were saprotrophic fungi (88 species), parasitic fungi (2 species), and entomogenous fungi (1 species), indicating that in the District, ectomycorrhizal fungi covered more than half of the total, being of significance in stabilizing local forest ecosystems. The analysis on the distribution patterns of the fungi at different altitudes and in different forest types and seasons showed that the species number decreased with increasing altitude but kept stable when the altitude reached a certain level, fungal growth was most prosperous in July-August and September-October, and the ranking of the species number in different forest types was Pinus armandii and Castanea seguinii mixed forest > Camellia spp. + Metasequoia glyptostroboides + Pinus yunnanensis mixed forest > Pinus armandii forest > Rhododendron natural forest. In contrast with the rather rich economic fungi in Bijie, only 16 species (8.6% of the total) were found in the local markets, suggesting that the exploitation and unitization potential of wild mushrooms in the District was still to be excavated.

Effects of soybean oligosaccharide on intestinal microbial community structure in Cherry Valley ducks.

2011, 30(06):  1185-1189. 

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In order to understand the effects of soybean oligosaccharide (SBOS) on the intestinal microbial community structure in Cherry Valley ducks, T-RFLP method was adopted to study the amounts of Escherichia coli, Bifidobacterium, and Lactobacillus in the duck caecum under effects of different concentration SBOS.
 Applying SBOS decreased the amount of E. coli in caecum. Compared with that of the control, the amount of E. coli in the 3rd and 4th week after applying 300 and 500 mg·kg^-1 of SBOS and in the 3rd weed after applying 700 mg·kg^-1 of SBOS had a significant decrease (P<0.05). Applying SBOS promoted the proliferation of Bifidobacterium and Lactobacillus, being significantly (P<0.05) in the 3rd and 4th weeks after applying 500 mg·kg^-1 of SBOS. No significant differences were observed between applying SBOS and aureomycin in the effect of regulating microbial community structure in duck intestine. Our results indicated that SBOS could effectively regulate the microbial community structure in Cherry Valley duck intestine, the effect was time- and dose-dependent, and the optimal additive dose was 500 mg·kg^-1.

Correlations between water quality and land use pattern in Taihu Lake basin.

2011, 30(06):  1190-1197. 

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Aimed to explore the correlations between land use pattern and water quality in heterogeneous landscapes, Taihu Lake basin was taken as a case, and was divided into 13 hydro-ecological units based on topography, land use pattern, and flow direction of major hydrological systems. The correlation analysis on the area proportions of different land use/cover types and water quality grade across the hydro-ecological units showed that the coefficient of variation of the water quality grade had a positive correlation with the area proportion of woodland, but a negative correlation with the area proportions of farmland and settlement, being significant for that of the settlement in non-flood season, which suggested that different land use types had different effects on water quality, i.e., woodland could improve water quality more effectively than farmland and settlement. The water quality grade of the hydro-ecological units was significantly positively correlated with the area proportion of farmland and of settlement in the flood season and non-flood season, respectively, but negatively correlated with that of woodland. There was a weak negative correlation between the water quality grade and the area proportion of wetland in the non-flood season, but a weak positive correlation in the flood season and in the whole year. The effect of the four major land use types in improving water quality in the flood season was in the order of woodland > wetland > settlement > farmland, and that in non-flood season was woodland > farmland > wetland > settlement, suggesting that woodland had the greatest positive contribution to the water quality, while farmland and settlement had the greatest negative contribution to the water quality in the flood season and non-flood season, respectively.

Patch dynamics of cropland and grassland in Zhangye oasis, Gansu Province in recent two decades.

2011, 30(06):  1198-1203. 

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By using GIS technology, this paper studied the patch dynamics of cropland and grassland in Zhangye oasis, Gansu Province in 1985-2006. In the study period, the predominant patch types of cropland were unchanged and expanded patches, while those of grassland were unchanged and shrunk patches. The common features of the patch dynamics of cropland and grassland were the largest mean area of unchanged patches (214.64 hm² for cropland and 149.5 hm² for grassland) and their smaller patch number and shape index, suggesting the patches having a higher aggregation degree in landscape scale and a concentrative and successive distribution, and the smallest shape index of newly generated patches (23.88 for cropland and 15.58 for grassland), suggesting their aggregative distribution. The differences of the patch dynamics of cropland and grassland were that cropland landscape was expanded mainly in the form of small patches on the basis of original patch, while grassland landscape was dominated by the shrinkage of original patch. In terms of the origins and fates of the patches, there existed a strong transformation among the cropland, grassland, and Gobi (matrix) patches in Zhangye oasis in recent two decades, and the main forces driving this transformation were population growth, water resources restriction, economic development, and climatic change.

Dynamic changes of settlement scale and road density in urbanization: A case stud in Nanjing City.

2011, 30(06):  1204-1209. 

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Based on the 1988, 1998, and 2006 Landsat TM images and road maps of Nanjing metropolitan region, this paper studied the dynamic changes of settlement percentage coverage (SPC), road density (RD), and their relationships during Nanjing in 1988-2006. In the study period, the settlements and road systems in the city expanded dramatically, but the relative growth rate (RGR) of SPC and RD decreased with their increasing processes. Comparatively, SPC increased faster than RD. The SPC/RD ratio increased rapidly with increasing SPC, but tended to be stable when the SPC increased to about 30%. SPC and RD all declined with  increasing distance from the urban center, but the annual mean RGR of RD changed less with the location and the time period. Comparing with road systems, settlement scale was more easily affected by local factors.

Tourism disturbance assessment of Jiuzhaigou Tourism Area based on landscape metrics.

2011, 30(06):  1210-1216. 

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The impact of tourism activity on landscape pattern is an important reflection of tourism disturbance, while landscape metrics are the quantitative indices in reflecting the changes of landscape pattern. In order to evaluate tourism disturbance, this paper selected landscape metrics to construct a tourism disturbance degree index with the consideration of tourism use extent and intensity. The index was then applied to evaluate the tourism disturbance in Jiuzhaigou tourism area. During the evaluation process, QuickBird image of the tourism area was selected, and 3S technology was used in the image interpretation and the tourism area partitioning (sub-areas 1-5). From the sub-area 1 to sub-area 5, the elevation was ascending, and the vertical distance of each sub-area was the same. Then, the tourism disturbance degree of each sub-area was calculated. The results indicated that from sub-area 1 to sub-area 5, the tourism use extent was the same but the tourism use intensity showed a decreasing trend, and thereby, the tourism disturbance degree had an overall decrease. Specifically, the tourism disturbance degree of sub-area 2 was the largest, followed by sub-areas 1 and 3, while those of sub-areas 4 and 5 were the smallest. As to each sub-area, the tourism disturbance degree didn’t have significant relationship with the mean patch fractal dimension, which demonstrated that the tourism disturbance had no significant effects on the land use pattern.

Accumulation of soil cadmium and subcellular distribution in Sorghum species.

2011, 30(06):  1217-1221. 

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The accumulation of soil cadmium (Cd) and subcellular distribution in three Sorghum plants (Sorghum bicolor (L.) Moench. cv. Hunnigreen, Sorghum bicolor × S. sudanense cv. Everlush and Sorghum sudanense (Piper) Stapf cv. Xinjiang) were studied in this paper. The Cd content in the different parts of the three Sorghum species was positively correlated with the concentration of Cd. The Cd accumulated in the roots of the three Sorghum species was higher than in stems and leaves.The acumulate ability to Cd were as follows： S. bicolor×S. sudanense > S. sudanense > S. bicolor.The subcellular distribution of Cd in leaves, stems and roots of the three Sorghum species were as follows: cell wall > soluble part > cell nucleus, chloroplast components > mitochondria.

Cadmium tolerance of and cadmium transportation and accumulation in Salix matsudana.

2011, 30(06):  1222-1228. 

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A hydroponic experiment was conducted to investigate the cadmium (Cd) tolerance of and the Cd transportation and accumulation in Salix matsudana. S. matsudana showed a relatively higher tolerance to Cd. Its growth was promoted by Cd when Cd concentration in the medium was 0.2 mg·L^-1. Phloem played an important role in the long distance Cd transportation from root to shoot. The top tissues of the plant had significantly higher Cd concentration (P<0.05) than the bottom tissues, and phloem had 14 times higher Cd concentration than xylem. Shoot had strong sustainable capability in accumulating Cd. The accumulated Cd in aboveground part, especially in leaves, accounted for 52%-62% of the total. Consequently, through cleaning out the fallen leaves of S. matsudana during its defoliation stage, soil Cd could be removed. S. matsudana would be a suitable plant for the phytoremediation of Cd-polluted soil.

Cd pollution of six vegetable species in wastewater irrigation area of Zhangshi, Shenyang.

2011, 30(06):  1229-1233. 

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Six seasonal vegetable species (lettuce, pepper, eggplant, cauliflower, tomato and welsh onion) and soil samples were collected from the vegetable growing farmland of Zhangshi wastewater irrigation area for Cd analysis. The uptake and accumulation ability of Cd in the edible part of the vegetable was evaluated using overproof multiple method, and the enrichment coefficient (EE) and translocation coefficient (TC) was employed to assess the efficiency of Cd uptake and transportation from soil to vegetables. Results indicated that Cd concentrations in the edible parts of lettuce, pepper and eggplant were higher among the six vegetables investigated, being 4.01, 1.78 and 1.24 mg·kg^-1 DW, respectively. The overproof amount of Cd in the edible part of these vegetables corresponded to 1.92, 2.28 and 2.01 times of that of the national food limited standards (0.20 mg·kg^-1 FW for leaf vegetables, and 0.05 mg·kg^-1 FW for solanaceous vegetables). Cd concentrations in the edible part of the rest vegetables were within the national food limited standards. The Cd concentration was 1.02, 1.20 and 0.83 mg·kg^-1 DW for tomato, cauliflower and welsh onion, respectively, with EE of 0.28, 0.36 and 0.52, respectively, which matched to the standard for low accumulated vegetables. EE was higher for lettuce with a value of 1.26, which indicated a comparatively large eco-risk if lettuce is to plant in Zhangshi soil or soil with similar Cd concentration level.

Effects of cadmium stress on DNA polymorphism of genome in Arabidopsis thaliana seedlings.

2011, 30(06):  1234-1239. 

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By using random amplified polymorphic DNA (RAPD) technique, the DNA polymorphism of genome in Arabidopsis thaliana seedlings leaves under Cd stress was studied, and, in combining with leaf morphological and physiological indices, the sensitive biomarkers indicative of Cd stress were chosen. After treated with 0.125-3.0 mg Cd·L^-1 for 21 days, the soluble protein content in A. thaliana seedlings leaves had an inverted U-shape increase with increasing Cd concentration, but no significant changes were observed in leaf fresh weight and chlorophyll content. Of the 12 decamer oligonucleotide primers tested, only 5 gave specific and stable results. In the control, 44 bands of the RAPD fingerprints from the leaves were easily distinguished. The changes in the RAPD fingerprints under Cd stress included the variation of band intensity, loss of normal bands, and appearance of new bands, in comparison with the control. In addition, the changes were dose-dependent. The above results showed that the genomic template stability was significantly affected by Cd stress, and the DNA polymorphism was sensitive to Cd stress. Thereby, the DNA polymorphism detected by RAPD technique could be used as a potential biomarker assay for the detection of Cd pollution and its related biological effects.

Boron distribution and its relationships with the allocation of other nutrient elements in different parts of pear seedlings.

2011, 30(06):  1240-1245. 

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By the methods of water culture, microwave digestion, and inductively coupled plasma (ICP), this paper studied the effects of boron (B) addition on the distribution of B in different parts of ‘Cuiguan’ pear (Pyrus pyrifolia) seedlings and its relationships with the absorption and allocation of P, K, Ca, Mg, Fe, Zn, Mn, and Cu. After treated with B, the B concentration in the seedlings was in the order of leaf > root > stem, and increased with increasing B addition. Root responded more intensively than leaf and stem. Higher B addition had significant effects on the allocation of test eight elements in the seedlings. With increasing B addition, root P, K, Mg, Zn, Mn, and Cu concentrations increased while Ca and Fe concentrations decreased, but the translocation coefficients of the eight elements all increased. The stem P, Ca, Mg, Zn, Mn, and Cu concentrations increased but K and Fe concentrations decreased with increasing B addition, the translocation coefficients of P and K increased, that of Fe had less change, while the translocation coefficients of other elements decreased. As for leaf, the P, K, Mn, and Cu concentrations increased with increasing B addition, Zn and Fe concentrations were in adverse, Ca and Mg concentrations decreased after an initial increase, and the translocation coefficients of the elements except Zn and Mn increased.

Dust lead contamination in rural households of several provinces in China.

2011, 30(06):  1246-1250. 

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One hundred and twenty one dust samples were collected from the rural households in eight provinces of China to measure the lead (Pb) concentration, speciation, and bio-availability. The mean Pb concentration in the household dusts was 207.5 mg·kg^-1. Among the eight provinces, Hunan and Yunnan had higher Pb concentration in their rural household dusts (537.8 and 280.1 mg·kg^-1, respectively), while Shaanxi and Fujian had a relatively lower one (96.0 and 80.1 mg·kg^-1, respectively). In the household dusts, Pb was mainly associated with Fe-Mn oxides (36.8%), followed by in residual form (17.7%), and associated with carbonate (16.7%). The exchangeable form (14.3%) and organic/sulphide form (14.4%) were relatively low. The bio-availability of Pb in the household dusts was 52.8%, and significantly correlated with Fe-Mn oxide Pb, suggesting the important contribution of Fe-Mn oxide Pb to the bio-available Pb.

A review on soil microbial community in different type constructed wetlands.

2011, 30(06):  1251-1257. 

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As an indispensable part of constructed wetland, soil microbes play an important role in the material transformation and energy flow in the wetland ecosystem. This paper reviewed the research progress in the detection methods of soil microbial community, its structure and composition, and relationships of soil microbial regulation effect with environmental parameters in different type constructed wetlands. Various kinds of novel molecular biological methods have proved to be useful tools for exploring soil microbial diversity in constructed wetland, among which, denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH) were the most frequently applied methods. The regulation effect of soil microbial community in constructed wetland mainly depended on wetland hydraulic condition, wastewater property (constituent composition, and pollutants characteristics and availability), filter material or soil type, plant, and various environmental factors. The species-specific composition of soil microbial community in different type constructed wetlands was dominated by phylum Proteobacteria, followed by the members of phylums Proteobacteria, Cytophaga-Flavobacterium, Actinobacteria, and Firmicutes. How to further improve the researches on the diversity of soil microbes involving in nitrogen cycle and to increase the removal efficiency of nitrogen from wastewater would be one of the key issues for further development of constructed wetland technology.

Effects of litter composition on soil organisms: A review.

2011, 30(06):  1258-1264. 

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Litter decomposition is a key process of nutrient cycle and energy flow in ecosystems, while soil microorganism and soil fauna are the main executants of litter decomposition. There are many studies addressed on the roles of soil organisms in litter decomposition, but the studies on the effects of litter decomposition on soil organisms are relatively scarce, and  the interactions between litter decomposition and soil organisms remain largely unclear. This paper briefly reviewed the studies on the effects of litter decomposition on soil microorganism and soil fauna, and discussed the key underlying mechanisms. The effects of litter decomposition on soil microorganism not only depend on litter properties (type or composition) and litter’s fragmentation degree, but also relate to the litter’s buried location. Many studies indicated that litter decomposition had remarkable effects on the community structure of soil fauna, and these effects were mainly from the alternations of soil organisms’ food source and habitat. It was proposed that the future research should focus on the long-term experimental studies across regions, integrated research on litter decomposition and ecosystem processes, and affecting mechanisms of litter decomposition on soil organisms.

Ecological functions of bryophyte: Recent research progress.

2011, 30(06):  1265-1269. 

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Bryophyte is a kind of higher plants with small size and simple structure, being the transitional form from aquatic to terrestrial and the most original group of existing higher plants. With the development of scientific research, people realized more and more the important roles of bryophyte in the structure and function of ecosystem. Some researches were made on the roles of bryophyte in environmental bio-monitoring, water and soil conservation, and forest regeneration. Aiming at the hotspots in environmental sciences research, and from the viewpoints of global climate change and ecosystem carbon, nitrogen, and phosphorus cycles, this paper summarized the recent research progress in the ecological functions of bryophyte, which could be helpful to deepen our understanding on bryophyte and to promote the researches of its ecological functions.

Application of biodiversity surrogates in rapid biodiversity assessment.

2011, 30(06):  1270-1278. 

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Biodiversity assessment is the basis for biodiversity conservation, while the application of biodiversity surrogate is one of the important means for quick biodiversity assessment in environmental impact assessment. This paper introduced the conception of biodiversity surrogate, analyzed the correlations widely existed among biological groups, and summarized the large scale experimental proportions among the species of  mammals,  birds and vascular plants (1:5:50). The existing biodiversity surrogates were classified into two categories, i.e., bio-surrogates (indicator group, functional group, and rare and endangered group) and habitat-based surrogates (environmental factors, landscape features, and sacred natural sites). Also, the surrogating mechanisms, effectiveness, use methods, and use scope of different indicators were summarized, and the potential ways to improve the surrogates’ performance were discussed. This paper provided references for conservation site planning, biodiversity monitoring, environmental impact assessment, and improvement of China’s biodiversity impact assessment system.

Changes of plant cell wall components under abiotic stresses: A review.

2011, 30(06):  1279-1286. 

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Plant cell wall mainly consists of cellulose, hemi-cellulose, pectic substances, lignin, and proteins. It has a number of functions, including maintain cell stability, transport materials, and protect cell against environmental stresses. When the plant life cycle is affected by various environmental signals, cell wall properties will have great change, and cell wall components content and structure will be also changed, which is supposed to be the causes of the changes in cell wall mechanical properties. These changes can be considered as the responses of plants to environmental stress. This paper summarized the research advances in the changes of cell wall polysaccharides and proteins content and structure and related enzyme activities, and the responses and relevant mechanisms of small molecules secreted to cell spaces under abiotic environmental stresses, such as water deficit, low temperature stress, heavy metals stress, and UV-B radiation. In considering of the recent researches at gene, genomic, and proteomics levels, the future research directions in this area were also discussed.

Spatial distribution characteristics of ecological field of floating bed system.

2011, 30(06):  1287-1294. 

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A model about the ecological field of floating bed system was constructed based on in situ experiment. The simulation results indicated that the ecological potential of floating bed system was the highest in ‘field source’, and decreased gradually with increasing horizontal and vertical distances to the ‘field source’. Plant kyegrass (Lolium multiflorum) biomass in the floating bed system had notable effects on the ecological potential. The more vigorous the plant grew, the higher the ecological potential was. In a 1 m × 1 m ecological floating bed and when the plant biomass was 39.40 kg·m^-2, the maximum affecting distance of ecological field was 1.86 m, and the maximum affecting area was 10.90 m². This model could simulate the spatial distribution characteristics of the ecological field of floating bed system, reflect the dynamic changes of plant growth with the spatial distribution of ecological field, and quantify the affecting degree of the floating bed system to the water quality at any point within the affecting scope of the bed system. The construction of this model could provide theoretical basis for the application of ecological floating bed in treating polluted water.

Forest health assessment based on self-organizing map neural network: A case study in Baihe Forestry Bureau， Jilin Province.

2011, 30(06):  1295-1303. 

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Through introducing self-organizing map (SOM) neural network into forest health assessment, and combining with geographic information system (GIS), a quantitative assessment was conducted on the health status of different forest types (broadleaved mixed forest, broadleaf-conifer mixed forest, and Larix olgensis forest) at subcompartment scale in the Baihe Forestry Bureau in Changbai Mountains, and a comparison was made on the health status of the sub-compartments with different average age, different average tree height, and different canopy density. The results showed that SOM neural network would be a more advanced approach for the automated and quantitative assessment of forest health. Its greatest advantage in the assessment of forest health was no need to know the priori knowledge about classification categories, and no need of the assessment indicators’ weights beforehand determined. As a result, SOM neural network could effectively overcome the interference of subjective factors, and let the classification results become more objective and accurate. The health level of test forest types was in the order of broadleaved mixed forest subcompartments Ⅲ> Ⅱ> Ⅰ> Ⅳ> Ⅴ, broadleaf-conifer mixed forest subcompartmentsⅡ> Ⅳ> Ⅰ> Ⅲ> Ⅴ, and Lalix olgensis forest subcompartments Ⅰ> Ⅱ> Ⅲ>> Ⅴ> Ⅳ. Relatively, the forest subcompartments that had greater average age and higher average tree height and canopy density would have higher level forest health. This study could provide theoretical support for the sustainable management and multifunctional use of the forests in Baihe Forestry Bureau.

Tropical cyclone disaster loss and damage grade assessment in Zhejiang Province.

2011, 30(06):  1304-1311. 

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By using the 2004-2008 tropical cyclone disasters data and social-economic information of the counties in Zhejiang Province, as well as the indices values with good regional contrast of relative affected population, relative disaster area, collapsed houses, and relative direct economic loss, which were built by revised conversion function, this paper established a disaster assessment model about the relative loss value of the indices and the hazard factors including process rainfall, rainstorm days, heary rain storm days, maximum daily rainfall, extreme and maximum wind speed (≥8 m·s^-1), and days of extreme and maximum wind speed by the method of polynomial fitting, and made a meticulous disaster grade classification of tropical cyclone via grey clustering and expert weighting. On these bases, the disaster assessment and grade dividing were given on the ‘Morakot’ tropical cyclone affected Zhejiang Province in 2009. The calculated indices values of relative affected population, relative disaster area, collapsed houses, and relative direct economic loss were approached to the actual indices values, with the correlation coefficients being 0.70, 0.63, 0.75, and 0.54, respectively, suggesting that the established assessment model could basically reflect the damage grade distribution caused by the hazard factors. The comperhensive rusults of ‘Morakot’ disaster assessment  accurately reflected the spatial distribution characteristics of different counties in the Province during the ‘Morakot’ event, but, affected by other factors (pregnancy disaster environment, vulnerability, and resilience, etc.), the fitted disaster was overestimated when the existing disaster was small, and underestimated when the existing disaster was great.

Spatial pattern of Stellera chamaejasme population in degraded alpine grassland in northern slope of Qilian Mountains, China.

2011, 30(06):  1312-1316. 

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By the methods of point pattern analysis and spatial sequence instead of time series, this paper studied the fine-scale spatial pattern of Stellera chamaejasme population in the degraded alpine grassland in northern slope of Qilian Mountains. With the increasing coverage of S. chamaejasme, its individual number decreased after an initial increase, young plants transited from random distribution to clumped distribution, aggregation intensity weakened after an initial strengthening, and elder plants showed a random distribution. When the coverage was lower, the S. chamaejasme population had a random distribution at 0-100 cm scale; when the coverage was higher, the distribution pattern transited from clumped to random with the development of the population. The spatial pattern had close correlation with the dispersion stage of the population. The dispersion of S. chamaejasme population was realized through the combination and annexation of patches, and the inter-conversion of competition and synergy.