Table of Content

18 February 2017, Volume 28 Issue 2

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Special Features for 2016 Annual Meeting of Ecological Society of China

Canopy vertical structure and understory plant regeneration of an evergreen broadleaved forest in Damingshan, Guangxi, China.

ZHOU Xiao-guo, WEN Yuan-guang, ZHU Hong-guang, WANG Lei, LI Xiao-qiong

2017, 28(2):  367-374.  doi:10.13287/j.1001-9332.201702.025

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In order to reveal the dynamics of canopy vertical structure and its effects on understory regeneration, we built 24 permanent plots (20 m×20 m) on the upslope, midslopeand downslope, respectively, in a typical evergreen broadleaved forest in Damingshan, Guangxi, China. We measured the crown area of each tree with diameter at breast height (DBH)≥1.0 cm, and surveyed the understory regeneration in growing season from 2009 to 2011. The results showed that the total canopy cover significantly increased from 54.0% in 2009 to 67.4% in 2011 after the frozen disaster in 2008. A significant difference existed in the cover and increment of different canopy layers. The canopy cover in the upper layers was markedly higher than that in the middle and lower layers. The increment of canopy coverage in the middle and lower layers was significantly higher than that in the upper layer. There were 55 regenerated woody plant species, and the dominant families and species of regenerated plants were in accord with those in the evergreen broadleaved forest. Biodiversity index of regenerated plants in the same slope position was significantly different among different years, and no significant difference was observed among different slope positions in the same year. The correlation between the coverage at different canopy layers and the species richness and abundance of regenerated plants was not significant. Total canopy cover and canopy coverage at the middle and lower layers were significantly negatively correlated with the Shannon index, Simpson index, and Pielou evenness index of the understory regenerated plants. It indicated that canopy coverage had a significant influence on the regeneration of understory, and the middle and lower layers had a stronger influence on the biodiversity of regenerated plants.

Population structure and spatial pattern of Quercus variabilis among different geographical areas, China.

GAO Wen-qiang, NI Yan-yan, LIU Jian-feng, WANG Xiao-fei, XUE Ze-min, JIANG Ze-ping, HE Guan-shun

2017, 28(2):  375-381.  doi:10.13287/j.1001-9332.201702.008

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Age structures and spatial distribution patterns of Quercus variabilis populations were analyzed across geographical gradients (latitude, longitude and altitude) by using the size-grading method and the ratio of variance to mean. The results showed as following: Over the horizontal gradient, the northern, middle, southern and western populations of Q. variabilis exhibited an inverse-J shape, but the eastern populations declined. The spatial patterns of adult individuals were all clumped except the northern populations which were randomly distributed. Juveniles were clumped in the northern, middle and western populations, but were randomly distributed in the southern and eastern populations. The aggregation intensity of juveniles across latitude decreased with the order as the central, northern and southern populations, but as the central, southern and northern populations for adult individuals. The aggregation intensity of both juveniles and adults across longitude followed a decreased order as the central, western and eastern populations. Along the altitudinal gra-dient, the inverse-J type occurred only in the low- and middle-altitude populations, but populations in the high altitude declined. The juveniles in populations among altitude gradient all were clumped, but the adults were all clumped except the low-altitude populations which were randomly distributed. The aggregation intensities of both juveniles and adults were higher in the middle than the other altitudinal populations. Compared with adults, juveniles generally had higher aggregation intensities across various geographical gradients. Our results revealed that the age structure and spatial distribution pattern of Q. variabilis were mainly determined by environment variation across geographical gradients and the species’ biological property, which supported the central-marginal hypothesis.

Age structure and growth characteristics of Juglans cathayensis seedling populations at different slope aspects in Wild Walnut Natural Conservation Area of Xinjiang, China

ZHANG Wei, LI Hai-yan, CUI Dong, YANG Yun-fei

2017, 28(2):  382-390.  doi:10.13287/j.1001-9332.201702.006

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For grasping the composition and growth characteristics of seedling populations of Juglans cathayensis, a national grade Ⅱ endangered plant, four 2-hm² plots were set up at different slope aspects in Wild Walnut Natural Conservation Area of Xinjiang, China. Adjacent lattice method was used to survey J. cathayensis seedlings. The relationships between the number, basal diameter and plant height of J. cathayensis seedling populations were analyzed. The results showed that seedlings at 1st age were more abundant on sunny, semi-sunny, shady and semi-shady slopes. The number of seedlings was predominant at 1st-3rd age. Seedling populations at different slope aspects showed an expanding age structure. 5.7% of 1st age seedlings could survive to 4th age, and 1.7% could survive to 7th age. The number of J. cathayensis seedlings had a critical turning point at the 3rd age. The seedlings of J. cathayensis were considered as r-strategists in their lives. The basal diameter and plant height of seedlings were slow-growing before 3rd age and fast-growing after 3rd age. Average growth rate of basal diameter was 3.6 mm·a^-1and decreased in the order of shady slope, sunny slope, semi-shady slope and semi-sunny slope. Average growth rate of plant height was 9.0 cm·a^-1 and decreased in the order of sunny slope, semi-sunny slope, semi-shady slope and shady slope. Basal diameter and plant height of seedlings exponentially increased with the increase of age. The relationships between plant height and basal diameter showed power function. Growth rates of seedling traits could be reflected by the properties and parameters of functions.

Dynamics of fine root decomposition and its affecting factors of Pinus massoniana in the Three Gorges Reservoir Area, China.

WANG Na, CHENG Rui-mei, XIAO Wen-fa, SHEN Ya-fei

2017, 28(2):  391-398.  doi:10.13287/j.1001-9332.201702.017

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A decomposition experiment for a year was conducted at Jiulingtou Forest Farm, Zigui County, Hubei Province, China to examine the decomposition dynamics of fine roots with different diameters (<0.5, 0.5-1 and 1-2 mm) and its main affecting factors for Pinus massoniana. The results showed that the decomposition rate decreased with the increasing root diameter. The annual decomposition rates for fine roots with diameters <0.5, 0.5-1 and 1-2 mm were 34.0%, 28.0% and 25.7%, respectively. The decomposition rate of <1 mm fine root decreased along time, and 1-2 mm fine root increased first and then decreased. In the fine root decomposition process, N, P and Ca concentrations increased along time, and K concentration decreased firstly, then increased, and then decreased along time. Fine root decomposition rate was significantly related to initial chemical composition (N, P, K, Ca, C/N and C/P) of fine roots. Ca concentration in fine root and soil temperature were the major factors affecting fine root decomposition.

Responses of non-structural carbohydrates of poplar seedlings to increased precipitation and nitrogen addition.

WANG Kai, LEI Hong, XIA Yang, YU Guo-qing

2017, 28(2):  399-407.  doi:10.13287/j.1001-9332.201702.012

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To understand the effects of precipitation increase and nitrogen addition on non-structural carbohydrates (NSC) of poplar seedlings, Populus × xiaozhuanica cv. Zhangwu seedlings were grown under a full factorial experimental design of two factors, i.e., three water treatments (W₁,natural precipitation; W₂, natural precipitation increased by 50%; W₃, increased by 100%) and four N fertilization levels (N₁,0 g N·m^-2·a^-1; N₂,5 g N·m^-2·a^-1; N₃,10 g N·m^-2·a^-1; N₄,15 g N·m^-2·a^-1). The results showed that changes in NSC contents in each organ of P. Zhangwu seedlings reflected significant interactions between precipitation increase and nitrogen addition. With the increase of precipitation, under the N₁ level, soluble sugar content was unchanged in leaves and branches, while the starch content decreased in leaves, branches, stems, coarse and fine roots. With the increase of precipitation, the soluble sugar content remained unchanged or declined, while the starch content decreased or firstly increased and then decreased in different organs under the N₂ and N₃ levels. The soluble sugar and starch contents increased or firstly decreased and then increased in different organs under the N₄ level. With the increase of N addition, the soluble sugar content remained unchanged and the starch content increased in leaves, soluble sugar content increased and starch content was unchanged in fine roots in the W₁ treatment. The soluble sugar content remained unchanged or firstly increased and then decreased, and the starch content decreased or firstly increased and then decreased in different organs in the W₂ treatment. The soluble sugar, starch and NSC contents increased in the W₃ treatment. In different precipitation and N addition treatments, the soluble sugar contents of P. Zhangwu seedlings ranged from 39.1 to 88.3 mg·g^-1, with the highest value observed in leaves and the lowest value in fine roots, and the starch content ranged from 23.3 to 46.8 mg·g^-1, with the highest in coarse roots and the lowest in fine roots.

Dust absorption capacities of eight evergreen broad-leaved plants in Beijing, China.

FAN Shu-xin, CAI Yu, DONG Li

2017, 28(2):  408-414.  doi:10.13287/j.1001-9332.201702.021

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Aiming at selecting the evergreen broad-leaved plants with excellent dust capturing capacity that can be applied in Beijing area for improving the urban vegetation dust removal, this study selected 8 evergreen (including semi-evergreen) broad-leaved plants used in urban green-space in Beijing area to measure the dust absorption per unit leaf area by the elution-mass method during winter and early spring in 2014. The dust deposition per leaf and per plant of each species was further calculated for tested species. Based on the dust capturing capacity measured in different units, cluster analysis on the comprehensive dust absorption capacities of different plants was carried out from the corresponding aspect. Results showed that the dust absorption ability differed significantly among the 8 evergreen broad-leaved (including semi-evergreen) species including Buxus sinica, Euonymus japonicus, Ligustrum quihoui, L. vicaryi, E. kiautschovicus, Indocalamus tessellatus, Phyllostachys violascens and Ph. aureosulcata. E. japonicus was best in dust absorption per unit leaf area and per plant, with 1.36 g·m^-2 and 59.63 g·plant^-1. I. tessellates (with 1.62 mg·leaf^-1) had the strongest dust absorption ability per leaf. With different measurement units selected, the ranking changed. The cluster analysis based on the multi index comprehensive dust absorption capacities could roughly divided the 8 evergreen broad-leaved species into 4 categories representing different dust absorption capacity levels. E. japonicus and Ph. sviolascens had the outstanding comprehensive dust capturing capacity, while B. sinica, L. vicaryi and Ph. aureosulcata showed the weak performance.

Leaf nitrogen and phosphorus stoichiometry of shrubland plants in the rocky desertification area of Southwestern Hunan, China.

JING Yi-ran, DENG Xiang-wen, WEI Hui, LI Yan-qiong, DENG Dong-hua, LIU Hao-jian, XIANG Wen-hua

2017, 28(2):  415-422.  doi:10.13287/j.1001-9332.201702.020

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In this paper, we took the leaves of shrubland plants in rocky desertification area in Southwestern Hunan as the research object to analyze the nitrogen (N) and phosphorus (P) stoichiometry characteristics for different functional groups and different grades of rocky desertification, i.e., light rocky desertification (LRD), moderate rocky desertification (MRD) and intense rocky desertification (IRD). The results showed that the average contents of N and P were 12.89 and 1.19 g·kg^-1, respectively, and N/P was 11.24 in common shrubland plants in the study area, which indicated that the growth of most plants were mainly limited by N. The content of N was declined in order of deciduous shrubs > evergreen shrubs > annual herbs > perennial herbs. The content of P and N/P were higher in deciduous shrubs than in perennial herbs. Significant differences were found among the main families of plants in terms of the contents of N, P and N/P in the study sites. The plants of Gramineae had the lowest contents of N and P, andtheir growth was mostly restricted by N, while Leguminosae had the highest content of N and N/P, and their productivity was majorly controlled by P. The contents of N and P in the leaves were significantly higher in dicotyledon plants and C3 plants than in monocotyledon plants and C4 plants, but the N/P was not significantly diffe-rent between these two plant categories. The nitrogen-fixing plants had higher content of N and N/P than the non-nitrogen-fixing plants, but the P content was not significantly different between these two plant groups. There were significant correlations between contents of N and P, N/P and N in all study plots. No significant correlation was found between N/P and P content in the examined rocky desertification sites, except for that in MRD. There were no significant differences of the contents of N, P and N/P under different grades of rocky desertification.

Effects of simulated nitrogen deposition and management type on soil enzyme activities in Moso bamboo forest.

PENG Chun-ju, LI Quan, GU Hong-hao, SONG Xin-zhang

2017, 28(2):  423-429.  doi:10.13287/j.1001-9332.201702.001

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In this study, a field experiment was conducted using simulated N deposition method in conventionally managed (CM) and intensively managed (IM) Moso bamboo forests to test the responses of five soil enzymes (including β-fructofuranosidase, cellulase, nitrate reductase, hydrogen peroxidase and urease) to simulated N deposition of four treatment levels of 0, 30, 60 and 90 kg N·hm^-2·a^-1. The results showed that compared with CM, IM significantly increased soil β-fructofuranosidase, cellulase, urease activities by 55.5%, 112.9% and 28.6%, respectively, but significantly decreased nitrate reductase activity by 31.5%, and had no significant effect on hydrogen peroxidase activity. Nitrogen deposition significantly decreased soil β-fructofuranosidase (20.0%-49.4% and 36.2%-45.1%), cellulase (20.5%-46.3% and 18.3%-49.0%), nitrate reductase (67.9%-85.2% and 15.2%-34.2%) activities in both CM and IM plots, respectively, and also urease activity (23.1%-47.6%) in IM, but enhanced the urease activity (8.1%-50.6%) in CM, and had no significant effects on hydrogen peroxidase activity. The combination of N deposition and management types significantly impacted the four soil enzyme activities except for hydrogen peroxidase.

Vertical distribution characteristics and temporal stability of soil water in deep profile on the Loess Tableland, Northwest China.

HAN Xiao-yang, LIU Wen-zhao, CHENG Li-ping

2017, 28(2):  430-438.  doi:10.13287/j.1001-9332.201702.011

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Study of impacts of land uses on spatiotemporal dynamics of soil water content (SWC) is of great significance for understanding the performance characteristics of regional water cycling under changing environment. Based on long-term located field observations, this paper explored the temporal dynamics of soil water in 0-15 m soil profile under four land use types on the Loess Tableland from September 2012 to December 2015. Results showed that the annually averaged SWCs over the 0-15 m soil profile for alfalfa field, fallow field, fertilized cropland and unfertilized cropland were 15.1%, 22.0%, 19.6% and 21.1%, respectively. Soil water contents along the shallow soil profile exhibited seasonal and annual wetting and drying cycle from March to June and July to October, and the profile depths were 0-2, 0-4.6, 0-3 and 0-4.2 m, respectively. Soil water contents along the deep soil profiles had better temporal stability and were influenced by land-use types. Du-ring the observation years, the yield and water consumption in alfalfa field increased, which caused the increase of deep soil desiccation, the 2-10 m soil profile had become stable dry layer, blocking the way of precipitation recharge.As for the soil water balance in other three land use types, it was negative in cropland and fallow field during winter wheat growing season, however, during spring maize growing season, it was negative in fertilized cropland but positive in unfertilized cropland and fallow field. During the fallow period, it was positive in the three land use types. The crop water use efficiency in the fertilized cropland was increased by more than 3 times than the unfertilized cropland.

Bayesian geostatistical prediction of soil organic carbon contents of solonchak soils in nor-thern Tarim Basin, Xinjiang, China.

WU Wei-mo, WANG Jia-qiang, CAO Qi, WU Jia-ping

2017, 28(2):  439-448.  doi:10.13287/j.1001-9332.201702.023

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Accurate prediction of soil organic carbon (SOC) distribution is crucial for soil resources utilization and conservation, climate change adaptation, and ecosystem health. In this study, we selected a 1300 m×1700 m solonchak sampling area in northern Tarim Basin, Xinjiang, China, and collected a total of 144 soil samples (5-10 cm). The objectives of this study were to build a Baye-sian geostatistical model to predict SOC content, and to assess the performance of the Bayesian model for the prediction of SOC content by comparing with other three geostatistical approaches [ordinary kriging (OK), sequential Gaussian simulation (SGS), and inverse distance weighting (IDW)]. In the study area, soil organic carbon contents ranged from 1.59 to 9.30 g·kg^-1 with a mean of 4.36 g·kg^-1 and a standard deviation of 1.62 g·kg^-1. Sample semivariogram was best fitted by an exponential model with the ratio of nugget to sill being 0.57. By using the Bayesian geostatistical approach, we generated the SOC content map, and obtained the prediction variance, upper 95% and lower 95% of SOC contents, which were then used to evaluate the prediction uncertainty. Bayesian geostatistical approach performed better than that of the OK, SGS and IDW, demonstrating the advantages of Bayesian approach in SOC prediction.

Responses of soil organic carbon and its labile fractions to nitrogen and phosphorus additions in Cunninghamia lanceolata plantations in subtropical China.

ZHANG Xiu-lan, WANG Fang-chao, FANG Xiang-min, HE Ping, ZHANG Yu-fei, CHEN Fu-sheng, WANG Hui-min

2017, 28(2):  449-455.  doi:10.13287/j.1001-9332.201702.024

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A series of nitrogen (N) and phosphorus (P) addition experiments using treatments of N₀(0 kg N·hm^-2·a^-1), N₁(50 kg N·hm^-2·a^-1), N₂(100 kg N·hm^-2·a^-1), P (50 kg P·hm^-2·a^-1), N₁P and N₂P were conducted at Cunninghamia lanceolata plantations in subtropical China. The responses of soil organic carbon (SOC), particulate organic carbon (POC) and water-soluble organic carbon (WSOC) to the nutrient addition treatments after 3 years were determined. The results showed that N and P additions had no significant effects on SOC concentration in 0-20 cm soil layer, while P addition significantly decreased soil POC content in 0-5 cm soil layer by 26.1%. The responses of WSOC to N and P addition were mainly found in 0-5 cm soil layer, and low level N and P addition significantly increased the WSOC content in 0-5 cm soil layer. Nitrogen addition had no significant effect on POC/SOC, while the POC/SOC significantly decreased by 15.9% in response to P addition in 0-5 cm soil layer. In 5-10 cm and 10-20 cm soil layers, POC/SOC was not significantly altered in N and P addition treatments. Therefore, the forest soil C stability was mainly controlled by P content in subtropical areas. P addition was liable to cause the decomposition of surface soil active organic C and increased the soil C stability in the short term treatment.

Ecological evaluation of different multiple cropping systems in red soil drylands.

CUI Ai-hua, ZHOU Li-hua, YANG Bin-juan, HUANG Guo-qin

2017, 28(2):  456-464.  doi:10.13287/j.1001-9332.201702.005

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In order to maximize the ecological function of red soil drylands and to determine the desirable multiple cropping systems, we evaluated the productivity, circulation of materials, energy and value flows in four multiple cropping systems on the basis of a consecutive three-year field experiment. Four multiple cropping systems were designed: treatment A (CK): wheat/soybean-sesame; treatment B: mixed green manure (rape × Chinese milk vetch × radish)-soybean ‖ maize-mung bean‖ sesame; treatment C: ryegrass-peanut‖ maize-millet‖ buckwheat; and treatment D: rape-mung bean‖ sweet potato; where interplanting was expressed as ‘/’, intercropping as ‘‖’, planting after harvest as ‘-’, and mixed cropping as ‘×’. Thirteen variables were employed to compare economic, ecological, and social benefits among the four cropping systems using grey relational analysis. The results showed that ‘mixed green manure (rape × Chinese milk vetch × radish)-soybean‖ maize-mung bean‖ sesame’ exhibited the highest grey relational degrees in terms of economic, ecological, and social benefits, and a highest grey relational degree at 0.847 in the integrative benefit. This treatment was the best multiple cropping pattern suitable for red soil drylands. Thus, this cropping system could have a positive impact on the layout and optimization of the structure of agricultural production in red soil dryland regions in the future.

Effects of different winter cover crops on soil organic carbon in a double cropping rice paddy field.

TANG Hai-ming, CHENG Kai-kai, XIAO Xiao-ping, TANG Wen-guang, WANG Ke, LI Chao, ZHANG Fan, SUN Yu-tao

2017, 28(2):  465-473.  doi:10.13287/j.1001-9332.201702.009

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In a double cropping rice field experiment, effects of five winter cover crops on the total organic carbon (TOC), active organic carbon (AOC), carbon pool management index (CPMI) and organic carbon storage were studied in three soil layers (0-5, 5-10 and 10-20 cm).Winter cover crops of ryegrass (Ry), Chinese milk vetch (Mv), potato (Po), and rape (Ra) between two rice crops were compared with fallow as control (CK). The results showed that the TOC and AOC contents under Ry, Mv, Po and Ra treatments were higher than those of CK in all three la-yers. Meanwhile, the TOC and AOC contents in Po treatment were higher than those of other treatments. Compared with CK, the AOC, activity index (AI), carbon pool index (CPI) and CPMI in the soil were improved through the recycling of winter cover crops straw. The AOC, AI, CPI and CPMI in the studied layers increased in order of Po>Mv>Ry>Ra>CK. The results indicated that the recycling of winter cover crops straw promoted the storage of SOC in the 0-20 cm soil profile as compared with CK. The strongest effect of the winter cover crops on the SOC storage occurred in Mv treatment, followed by Mv and Po treatments, and the SOC storage increased with the increasing soil depth.

Interspecific relationship and Si, N nutrition of rice in rice-water spinach intercropping system.

NING Chuan-chuan, YANG Rong-shuang, CAI Mao-xia, WANG Jian-wu, LUO Shi-ming, CAI Kun-zheng

2017, 28(2):  474-484.  doi:10.13287/j.1001-9332.201702.015

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Intercropping is a sound eco-agriculture model, but aquatic crops (e.g., rice) intercropping is seldom researched. In the present study, rice and water spinach were chosen as the research objects, a field trial was conducted to explore the yields, interspecific relationship and Si, N nutrition of rice under rice-water spinach intercropping for four seasons during two consecutive years (2014-2015). The experiment had five treatments: rice monoculture, water spinach monoculture, and rice-water spinach intercropping ratios of 2:2, 3:2, 4:2, respectively. The results showed that rice-water spinach intercropping significantly increased rice yield, and the increase rates of 2:2, 3:2 and 4:2 intercropping per unit area were 77.5%-120.6%, 64.9%-80.9%, 37.7%-56.0%, respectively. However, intercropping resulted in reduction of water spinach yield. Intercropping significantly increased total yield of rice and water spinach from land equivalent ratios (LER) analysis. The values of LER were more than 1.0, and the ratio of 3:2 intercropping had the best effect. As for the competitive index, rice was more competitive than water spinach in intercropping system, especially in early season. Compared with rice monoculture, rice-water spinach intercropping significantly increased the absorption of Si and N in rice leaves, and Si content of rice leaves during ripening stage, but didn’t increase its N content and even slightly reduced it during ripening stage. Intercropping had no significant effect on available Si, ammonium N and nitrate N content in soil. Compared with rice monoculture and intercropping, water spinach monoculture had always the highest available Si, ammonium N and nitrate N contents in soil through the experiment period. The results suggested that rice-spinach intercropping could promote rice to absorb silicon and nitrogen and increase the competitive ability of rice.

Characteristics of atmospheric visibility change and its influence factors in Hefei City, Anhui, China.

SHI Min-min, ZHANG Qing-guo, ZHANG Hao, WANG Feng-wen

2017, 28(2):  485-492.  doi:10.13287/j.1001-9332.201702.029

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Using the observation data of Hefei atmospheric visibility and meteorological elements and PM_2.5 and PM₁₀ concentrations at same period from October 2013 to June 2015, based on comprehensive analysis of the impact factors on atmospheric visibility, the relationships among the relative humidity (RH), PM_2.5 and PM₁₀ concentrations and visibility were explored. The results showed that the correlation between RH and Hefei atmospheric visibility was most significant during the period of study. When RH<60%, the coefficients of correlation between PM_2.5, PM₁₀ concentrations and atmospheric visibility increased gradually with the increasing RH. When RH>60%, the coefficients of correlation between the particles concentration in atmosphere and atmospheric visibility showed a decreasing trend. When 50%≤RH<60%, the coefficients of correlation between PM_2.5, PM₁₀ concentrations and atmosphere visibility were higher. When RH was relatively higher, the atmospheric visibility was mainly affected by the relative humidity, on the contrary, the concentration of particles had a greater influence on the visibility. When RH>70%, the change amplitude of contour line of atmospheric visibility was larger, and the impacts of RH on atmospheric visibility were intensified. According to the formula fitted by the data of RH, PM_2.5, PM₁₀ concentrations and atmospheric visibility, the nonlinear fitting model was better than multivariate linear fitting model in simulating the change of atmospheric visibility.

Spatial and temporal patterns of the ecological compensation criterion in Jiangxi Province, China based on carbon footprint.

HU Xiao-fei, ZOU Yan, FU Chun

2017, 28(2):  493-499.  doi:10.13287/j.1001-9332.201702.026

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Carbon footprint is a new method to measure carbon emissions, and the ecological compensation criterion can be determined according to the regional carbon footprint and carbon carrying capacity. The spatial and temporal patterns of ecological compensation criterion were studied among 11 cities in Jiangxi Province using carbon footprint, carbon capacity and carbon surplus/deficit models. Our results found that carbon footprint in Jiangxi Province showed a rapid growth trend from 2000 to 2013, with an average annual growth rate of 8.7%. The carbon carrying capacity always remained surplus, but the net carbon surplus amount decreased from 2000 to 2013. Among the 11 cities, Nanchang and Jiujiang made the biggest contribution to total carbon emission, and Ganzhou, Ji’an and Shangrao had provided the largest contribution to carbon total absorption. In 2013, the total carbon surplus amount was 2.273 billion yuan in Jiangxi Province. Ganzhou, Ji’an, Fuzhou and Shangrao should be given priority to ecological compensation money. These results could provide a scientific basis for the establishment of ecological compensation mechanism in Jiangxi Province and the transfer of CO₂ emission rights.

Comparing the value of ecological protection in Sanjiang Plain wetland, Northeast China based on the stated preference method.

FAN Zi-juan, AO Chang-lin, MAO Bi-qi, CHEN Hong-guang, WANG Xu-dong

2017, 28(2):  500-508.  doi:10.13287/j.1001-9332.201702.002

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Stated preference method is usually used to evaluate the non-market value of environmental goods which includes contingent valuation method (CVM) and choice experiments (CE). In this paper, stated preference method was adopted to evaluate the non-market value of Sanjiang Plain wetland. A willingness to pay (WTP) evaluation model of stated preference method was constructed based on the random utility theory. The average WTP of CVM and CE was obtained, respectively. The average WTP elicited by CE was 379 yuan per year, and the marginal WTPs of different selection properties including water conservation, wetland area, natural landscape and biodiversity were114.00, 72.55, 59.55 and 37.09 yuan per year, respectively. Meanwhile, the average WTP elicited by CVM was 134 yuan per year. The influence of factors on WTP was analyzed and reasons for protest responses were discussed. Results showed that the respondents’ WTP elicited by CE was signi-ficantly higher than that by CVM, and respondents’ socio-economic attitudes such as level of education and personal annual income had a significant positive impact on respondents’ WTP. There were no significant difference in the reasons of protest responses between CVM and CE. Besides, respondents’ multiple attributes and multiple levels analysis could be carried out by CE and the WTP of wetland’s selection attributes could be calculated. Therefore, CE had the better ability of revealing respondents’ preference information than CVM and its assessment results were more close to the actual value.

Effects of habitat fragmentation on species diversity of ground dwelling beetles in the Thousand-Island Lake region, Zhejiang, China.

ZHOU Wen-jie, LUO Yuan-yuan, ZHONG Lei, PAN Lin

2017, 28(2):  509-518.  doi:10.13287/j.1001-9332.201702.037

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The ground dwelling beetles on 20 land-bridge islands and 8 mainland sites in the Thousand-Island Lake region were collected by pitfall trap methods for six times from July 2012 to April 2014 (in three seasons, spring, summer and autumn). The species abundance, composition, diversity and seasonal dynamics of ground dwelling beetles were analyzed. Besides, the relationship between island spatial attributes (e.g., island area and isolation) and the diversity of ground dwe-lling beetles were studied. There were 3370 litter-dwelling beetle individuals belonging to 26 families and 101 species.For species richness of ground dwelling beetles, there were significant diffe-rences between the large islands and mainland sites, the mean density on small islands was significantly higher than on mainland sites. The species turnover was higher among mainland sites than among islands. The species richness on islands was significantly associated with island area, and the density was significantly associated with the distance to mainland. The species richness of islands in summer was higher than that in spring and autumn. Shannon, Simpson and Pielou indices of islands and mainlands were all highest in summer and lowest in autumn.

Soil microbial community structure in Picea asperata plantations with different ages in subalpine of western Sichuan, Southwest China.

LUO Da, LIU Shun, SHI Zuo-min, FENG Qiu-hong, LIU Qian-li, ZHANG Li, HUANG Quan, HE Jian-she

2017, 28(2):  519-527.  doi:10.13287/j.1001-9332.201702.028

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The effects of four Picea asperata plantations with different ages (50-, 38-, 27- and 20-year-old), in subalpine of western Sichuan, on the characteristics of soil microbial diversity and microbial community structure were studied by the method of phospholipid fatty acid (PLFA) profiles. The results showed that, with the increase of age, the contents of soil organic carbon and total nitrogen gradually improved, while Shannon’s diversity index and Pielou’s evenness index of soil microorganisms increased at first and then decreased. The amounts of microbial total PLFAs, bacterial PLFAs, fungal PLFAs, actinobacterial PLFAs, and arbuscular mycorrhizal fungal (AMF) PLFAs in soils consistently increased with increasing age. The principal component analysis (PCA) indicated that the soil microbial communities in different plantations were structurally distinct from each other. The first principal component (PC1) and the second principal component (PC2) together accounted for 66.8% of total variation of the soil microbial community structure. The redundancy analysis (RDA) of soil microbial community structure and environmental factors showed that soil organic carbon, total nitrogen, total potassium, and fine root mass were the key determinants influencing the microbial community structure. Our study suggested that, with the extension of artificialafforestation time, the soil fertility and microbial biomass were enhanced, and the restoration processes of forest ecosystem were stable.

Small unmanned aerial vehicles for low-altitude remote sensing and its application progress in ecology.

SUN Zhong-yu, CHEN Yan-qiao, YANG Long, TANG Guang-liang, YUAN Shao-xiong, LIN Zhi-wen

2017, 28(2):  528-536.  doi:10.13287/j.1001-9332.201702.030

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Low-altitude unmanned aerial vehicles (UAV) remote sensing system overcomes the deficiencies of space and aerial remote sensing system in resolution, revisit period, cloud cover and cost, which provides a novel method for ecological research on mesoscale. This study introduced the composition of UAV remote sensing system, reviewed its applications in species, population, community and ecosystem ecology research. Challenges and opportunities of UAV ecology were identified to direct future research. The promising research area of UAV ecology includes the establishment of species morphology and spectral characteristic data base, species automatic identification, the revelation of relationship between spectral index and plant physiological processes, three-dimension monitoring of ecosystem, and the integration of remote sensing data from multi resources and multi scales. With the development of UAV platform, data transformation and sensors, UAV remote sensing technology will have wide application in ecology research.

Original Articles

Scaling relationships between twig size and leaf size of Pinus hwangshanensis along an altitudinal gradient in Wuyi Mountains, China.

LI Man, ZHENG Yuan, GUO Ying-rong, CHENG Lin, LU Hong-dian, GUO Bing-qiao, ZHONG Quan-lin, CHENG Dong-liang

2017, 28(2):  537-544.  doi:10.13287/j.1001-9332.201702.039

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To analyze the tradeoff relationship between twigs and leaves, the traits of Pinus hwang-shanensis including leaf area, leaf number, twig length and twig diameter were investigated in Wuyi Mountains along an altitudinal gradient. The results indicated that leaf number, twig length, twig diameter, leafing intensity and twig stem cross-sectional area of P. hwangshanensis increased gra-dually with the increasing altitude, while individual leaf area decreased gradually. Leafing intensity of P. hwangshanensis at different altitudes had significant negative relationships with leaf area. The cross-sectional area of P. hwangshanensis had significant positive relationship with total leaf area. Twig length and twig diameter of P. hwangshanensis correlated negatively with leafing intensity, but positively with leaf area, leaf number and total leaf area. To enhance the competitiveness and resource utilization efficiency, P. hwangshanensis at low altitude tended to have relatively few large leaves on short twigs, and those at high altitude tended to have a large number of small leaves on long twigs. Such tradeoff between twigs and leaves reflected the strategy of resource utilization and the balance of biomass allocation mechanism of P. hwangshanensis responding to the altitudinal change.

Characteristics of nitrogen transportation in Castanea mollissima forest around the Fushi Reservoir watershed in north Zhejiang Province, China.

WANG Qing-bing, CAO Yi-ni, ZHANG Jian-feng, CHEN Guang-cai, LI Ze-bo, WU Hao, WANG Li

2017, 28(2):  545-553.  doi:10.13287/j.1001-9332.201702.018

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In this study, through setting runoff plots in Chinese chestnut (Castanea mollissima) fo-rest, the runoff water samples were collected and tested from January to October, 2013. Combining with soil nitrogen data before and after the rainy season, we analyzed the characteristics of soil nitrogen transportation in chestnut forest around the Fushi Reservoir watershed in north Zhejiang Pro-vince, China. The results showed that among the 10 surface runoff events of Chinese chestnut fo-rest, there exhibited a significant difference in runoff water volume of each runoff plot, and the maximum amount was 0.51 m³. Nitrogen was the major element associated with nutrient loss in the study region. The concentrations of nitrate nitrogen (NO₃^--N), ammonium nitrogen (NH₄⁺-N), total nitrogen (TN) andchemical oxygen demend (COD_Mn) in the runoff water ranged from 0.02-1.87, 0.04-3.53, 1.69-5.33 and 5.30-14.07 mg·L^-1, respectively. The water quality indexes were greatly affected by the runoff volume, and the relationship between the amount of nitrogen loss and runoff could be well fitted by using a linear equation. The difference in nitrogen contents of the soil in the upper, middle and lower part of the runoff plots was evident both before and after the rainy season. Moreover, the nitrogen content increased with the increasing altitude, but this trend decreased with increasing soil depth. Comparison of the difference between the four forms of soil nitrogen (NO₃^--N, NH₄⁺-N, TN and hydrolyzable nitrogen Hydro-N of soil) before and after the rainy season showed that there existed significant differences in Hydro-N and TN, and the average diffe-rence values were 20.21 and 307.49 mg·kg^-1, respectively. In this area, there was a great risk of nitrogen loss with runoff, and the potential non-point source pollution in Fushi Reservoir should be concerned.

Effects of combined application of water retention agent and organic fertilizer on physico-chemical properties of iron tailings.

LI Xiang, ZHANG Bao-juan, LI Ji-quan, LI Yu-ling, LI Chen-guang

2017, 28(2):  554-562.  doi:10.13287/j.1001-9332.201702.036

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In order to analyze the effects of combined application of water retention agent and orga-nic fertilizer on physico-chemical properties of iron tailings and to find the optimal proportion of water retention agent and organic fertilizer for the improvement of iron tailings, the experimental plots of the combination trials with 2 factors in 4 levels were designed in the iron tailings of Qian’an Shougang through investigating some indexes of physico-chemical properties such as bulk density, moisture capacity, porosity, pH and the contents of organic matter, nitrogen, phosphorus and potas-sium. The biomasses of Medicago sativa and Amorpha fruticosa planted in the experimental plots were measured to verify the improvement effects. 4 levels of super absorbent polymers (L·m^-3) used in treatments were 0 (B₀), 10 (B₁), 50 (B₂), 100 (B₃), and 4 levels of organic fertilizer (kg·m^-2) were 0(N₀), 2.25 (N₁), 11.24 (N₂), 22.49 (N₃). The improving effects of different treatments on physico-chemical properties of iron tailings were mainly reflected in the surface layer of 0-20 cm. All the tested indexes were significantly different from control (CK) in the layer of 0-20 cm. The improvement effects of organic fertilizer on physical and chemical properties of iron tai-lings were better than that of water retention agent. In the 0-20 cm layer, the bulk density, non-capillary porosity, organic matter, rapidly available phosphorus, and available potassium under all treatments of adding water retention agent individually were not significantly different from the CK, while significant difference was observed when the organic fertilizer was solely applied in B₀N₂ and B₀N₃ treatments. The improvement synergy effect of organic fertilizer and water retention agent was better than that of organic fertilizer or water retention agent, respectively. In 0-20 cm layer, all the indexes obtained from treatment B₃N₃ performed best and were significantly different from the CK, which was the optimum for the improvement of iron tailings.

Effects of straw incorporated to different locations in soil profile on straw humification coefficient and maize yield.

ZOU Wen-xiu, HAN Xiao-zeng, LU Xin-chun, HAO Xiang-xiang, YOU Meng-yang, ZHANG Yi-he

2017, 28(2):  563-570.  doi:10.13287/j.1001-9332.201702.022

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Tillage and straw incorporation are important agricultural practices that can break plough layer and improve black soil fertility. The effects of tillage and straw incorporation on straw humification coefficient, soil organic carbon (SOC), and maize yield were investigated in a field experiment. Subsoil combined with straw incorporation in 20-35 cm soil layer (ST+S) could break plough layer and decrease the bulk density by 5.7%, 3.3% and 5.7% compared with traditional til-lage (TT), subsoil (ST) and traditional tillage combined with straw incorporation (TT+S) in six experimental years, respectively, and the best effects were observed in ST and ST+S treatments in the first expe-rimental year. The rate of straw decomposition was higher in 0-20 cm (72.0%) than in 20-35 cm (59.2%), and the straw humification coefficient in 0-20 cm and 20-35 cm soil la-yers reached the peak in first experimental year with 15.9% and 12.7%, respectively. Compared with initial soil sample, SOC and light fraction organic carbon (LFOC) of TT, ST and ST+S treatments in 0-20 cm soil layer was decreased in experimental years, but was increased by 2.9% and 12.4% within TT+S, respectively. SOC and light fraction organic carbon (LFOC) of ST+S in 20-35 cm soil layer was increased by 9.2% and 9.9%, respectively. The effect of field treatments on maize yield showed in a decreasing trend of ST+S>TT+S>ST>TT, effects of tillage and straw incorporation on maize yield could continue 3 and 6 years, respectively, indicating that tillage and straw incorporation had time effect. Therefore, straw incorporated into 20-35 cm soil layer based on tillage was an effective, sustainable agricultural practice of improving black soil quality.

Effects of water conditions and controlled release urea on yield and leaf senescence physiological characteristics in summer maize.

LI Guang-hao, LIU Ping-ping, ZHAO Bin, DONG Shu-ting, LIU Peng, ZHANG Ji-wang, TIAN Cui-xia, HE Zai-ju

2017, 28(2):  571-580.  doi:10.13287/j.1001-9332.201702.007

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In an soil column experiment with Zhengdan 958 (a summer maize cultivar planted widely in China), treatments of three water levels,severe water stress W₁ which the soil moisture kept (35±5)% of the field capacity, mild water stress W₂ which was (55±5)%,normal water W₃ which was (75±5)%, and four levels of controlled release urea fertilizer (N₀, N₁ was 150 kg N·hm^-2,N₂ was 225 kg N·hm^-2 and N₃ was 300 kg N·hm^-2) were included to study the interactive effects of water and controlled release urea on yield and leaf senescence characteristics of summer maize. The results showed that the coupling of water and controlled release urea had significant effects on increasing yield, delaying the senescence and keeping the high efficiency of the functional leaves. Under the same nitrogen condition, yield, LAI, chlorophyll content and the activities of SOD, POD, CAT and soluble protein content in summer maize ear leaf were significantly increased with more water supplying, and the content of MDA decreased significantly. Under the condition of the same moisture, these indicators were also significantly increased with the increasing nitrogen application and MDA content was reduced significantly. However, these indicators (except MDA) of W₃N₃, W₃N₂ and W₂N₃ treatments were maintained at a higher level and the MDA content was lo-wer compared with other treatments despite the fact that there were no significant difference among these three treatments, which indicated that the interactive effects of water and controlled release urea had an important role in maintaining the function of ear leaf, delaying the leaf senescence, and was beneficial to the photosynthates production and obtaining higher yield of summer maize. Integrating the yield, LAI, chlorophyll content, various protective enzymes activity, MDA and soluble protein content, controlled release urea application rate of 225 kg N·hm^-2 was the best treatment as the soil moisture content was (75±5)% of field capacity. Continuous increase in the nitrogen application could not enhance the activities of protective enzymes, oppositely, it could cause the decline of protective enzymes activities and the increase of MDA content rapidly and speed up plants translation to senescence, which was not conductive to the efficient use of nitrogen. We suggested that coupling controlled release urea application rate of 300 kg N·hm^-2 with soil moisture content of (55±5)% of field capacity was optimum.

Temporal variation of soil net nitrogen mineralization in summer maize growing period under plastic film mulched cultivation in Danjiangkou Reservoir Area, China.

WANG Wei, YU Xing-xiu, HAN Qiang, XU Miao-miao, REN Rui, ZHANG Jia-peng

2017, 28(2):  581-588.  doi:10.13287/j.1001-9332.201702.014

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Soil net nitrogen mineralization in cropland has a great influence on both agricultural non-point source pollution and soil nitrogen loss. A field plot experiment was conducted to explore the temporal variation of soil net nitrogen mineralization under plastic film mulching ridge-furrow in Wulongchi small watershed during summer maize growing period. Results showed that the soil net ammonification, nitrification, and nitrogen mineralization were significantly greater than those of non-mulched treatment, and the differences were 6.63, 12.96 and 19.59 mg·kg^-1, respectively. During the summer maize growth period, the rate of soil net ammonification was high at seedling stage, low at heading stage, and high at maturation stage. Both the rates of soil net nitrification and nitrogen mineralization were high at jointing stage, low at heading stage, and high at maturation stage. The rate of soil net nitrogen mineralization under plastic film mulched had significant linear relation with the contents of soil total nitrogen, nitrate nitrogen, and soil water. In conclusion, the improved condition of soil water and temperature under plastic film mulched cultivation of summer maize in the growing period promoted soil net nitrogen mineralization.

Trends and temporal-spatial distribution of fiber quality in the national cotton variety regional trials.

TANG Shu-rong, GUO Rui-lin, WEI Jing-yan, MENG Jun-ting, WEI Shou-jun, YANG Wei-hua, ZHOU Zhi-guo

2017, 28(2):  589-602.  doi:10.13287/j.1001-9332.201702.027

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This study applied a grey predicting model to predict the trend of cotton fiber quality for next 5 and 10 years in the Yellow River Valley (YeRV), the Yangtze River Valley (YaRV) and the Northwest Inland Region (NWIR) based on the data set from the fiber quality traits of candidate cultivars in National Cotton Variety Regional Trials during 2005-2014. The temporal and spatial distributions of cotton trails in the three major cotton producing regions were analyzed. The results showed that the overall fiber quality of the Regional Cotton Variety Trials was improved during 2005-2014. Fiber length showed excellence and the distribution of threshold increased to 27.0-32.0 mm, and the fiber length of most cultivars reached 29 or 30 mm. Fiber strength also showed an increase trend. The proportion of high level (31.0 cN·tex^-1) cultivars in YaRV was as high as 61.1% in 2011. Micronaire was significantly different among the three major cotton producing regions. In YeRV, micronaire was increased from class B₂(4.3-4.9) to class C₂(≥5.0). In YaRV, it maintained in a high level of class C₂; while it performed excellent in class A (3.7-4.2) and B₂ (4.3-4.9) in NWIR. As a comprehensive fiber quality trait, spinning consistency index decreased from NWIR, YaRV to YeRV, and was ranged from 130 to 149, which was suitable for 40-50 spun yarn and accounted for about 80.0% over the total. We concluded that NWIR had the best fiber quality, followed by YaRV and YeRV in recent ten years. In the near future, fiber quality in the regional cotton variety trails would slightly increase in YaRV, but significantly decrease in YeRV and NWIR. These changes should be highly concerned for breeders, the committee of National Cotton Variety Regional Trials and approval of management department in China.

Prediction of Cd in vegetables and soil Cd threshold derivation based on transfer function.

YANG Yang, WANG Mei-e, LI Yan-ling, CHEN Wei-ping, PENG Chi

2017, 28(2):  603-608.  doi:10.13287/j.1001-9332.201702.034

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The construction of transfer function of cadmium (Cd) in the soil-vegetable system is important for risk management. This study investigated the Cd concentration in 745 paired soils and vegetable samples, aiming to determine the influences of major soil properties on uptake of Cd by vegetables, and to derive the soil Cd threshold for vegetable cultivation based on China foodstuff regulations. Results of species sensitivity distribution model showed that the Cd accumulation potential of leafy vegetables was greater than that of rootstalk vegetables. Stepwise multiple regression analysis showed soil total Cd, pH, and soil organic matter (SOM) were major factors contributing to Cd accumulation in vegetables. The derived transfer function explained 54.2% and 69.1% of the variance for the accumulation of Cd in leafy and rootstalk vegetables, respectively. The derived soil threshold increased with soil pH and SOM contents. The rootstalk vegetables were potentially hazardous when grown in strong acidic areas. For soils in the southern China with excessive acidic nature and low SOM contents, the soil Cd limits for vegetables cultivation might be over-estimated.

Relationships of wheat seed vigor with enzyme activities and gene expression related to seed germination under stress conditions.

CHEN Lei-tai, SUN Ai-qing, YANG Min, CHEN Lu-lu, MA Xue-li, LI Mei-ling, YIN Yan-ping

2017, 28(2):  609-619.  doi:10.13287/j.1001-9332.201702.019

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This study aimed to analyze the enzyme activities and gene expression differences related to seed germination in different wheat genotypes, and to clarify the relationship between seed vigor and the related enzyme activities as well as gene expression under stress germination conditions. We measured seed vigor, total soluble sugar content, soluble protein content, α-amylase activity, cysteine protease activity and gene expression of the related enzymes of four wheat cultivars under drought, artificial aging and cold soaking stress. Results showed that drought, artificial aging and cold soaking stress affected seed vigor to some extent. Under different germination conditions, total soluble sugar content showed an increasing trend with small amplitude at first and then decreased with small amplitude and after that increased rapidly again, while soluble protein content in the four cultivars gradually decreased with germination time. The α-amylase activity of the four cultivars showed a rising trend on the whole, but that of Yunong 949 and Lunxuan 061 declined after germinating for 60 hours after cold soaking stress. Cysteine protease activity decreased at first and then increased as a whole. However, under drought stress condition, cysteine protease activity of Yunong 949, Yumai 49-198 and Lunxuan 061 increased at first and then decreased and finally increased again. The α-AMY (α-amylase gene) expression levels increased at first and then decreased as a whole under different germination conditions. The expression level of α-AMY in Lunxuan 061 after cold soaking stress was higher than that of CK, while the α-AMY expression levels in four cultivars under other stress germination conditions were lower than that of CK. The expression level of CP (cysteine protease gene) showed an increasing trend. No significant difference of CP expression level was found in Chang 4738 between artificial aging treatment and CK. The CP expression levels in the four cultivars under other stress conditions were higher than that of CK. The results demonstrated that there was no direct relationship between the enzyme activities and gene expression levels of α-amylase and cysteine protease under different germination conditions. The α-amylase activity and total soluble sugar content had an extremely significant positive correlation, but the correlation between cysteine protease activity and soluble protein content was not significant. The α-amylase activity significantly positively correlated with vigor index under standard germination condition. However, the α-amylase activity had no significant correlation with vigor index under stress conditions. After cold soaking stress, cysteine protease activity significantly positively correlated with vi-gor index during seed germination, but the correlation was not significant under standard germination, drought stress and artificial aging.

Capacity of extensive green roof to retain rainwater runoff in hot and humid region.

LIU Ming-xin, DAI Se-ping, ZHOU Tian-yang, RUAN Lin, ZHANG Qiao-song

2017, 28(2):  620-626.  doi:10.13287/j.1001-9332.201702.038

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The water logging has become the environmental problem of major cities with the sharp increase of impermeable urban pavement as the contributing cause. Abroad, the green roof has been widely used as a practical measure to intercept rainwater, yet the capacity of green roof to retain rainwater varies with climate conditions. As the hot and humid climate zone features high temperature, humidity and precipitation, it is meaningful to study the capacity of green roof to retain rainwater under such climatic condition. In this research, 3 plat forms were set up in Guangzhou in rainy and hot summer to test the capability of simple green roof to retain rainwater runoff, and the efficiency of green roof to retain rainwater under local climate conditions was worked out based on the meteorological observation and data measurement during the 13-month test period. The results showed that the simple green roof with a substrate thickness of 30, 50 and 70 mm could retain 27.2%, 30.9% and 32.1% of precipitation and reduce the average peak value by 18.9%, 26.2% and 27.7%, respectively. Given an urban built-up area of 1035.01 km² in Guangzhou and a roof area percentage of approximately 37.3% and assuming the green roofs with 30 mm-thick substrate were applied within the area, the light, medium and heavy rain could be delayed at 72.8%, 22.6% and 17.4%, respectively. Accordingly, the rainwater retained could reach up to 14317×10⁴ m³. It suggested the great potential of the simple green roof in retaining rainwater. The research could serve as reference for the hot and humid climate zone to alleviate water logging and visualize sponge city construction.

Constructing ecological security patterns in mountain areas based on geological disaster sensitivity: A case study in Yuxi City, Yunnan Province, China.

PENG Jian, GUO Xiao-nan, HU Yi-na, LIU Yan-xu

2017, 28(2):  627-635.  doi:10.13287/j.1001-9332.201702.013

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As one of the key topics in the research of landscape ecology, regional ecological security patterns can effectively promote regional sustainable development and terrestrial ecological barriers construction. It is extremely important for middle Yunnan, with frequent disasters and fragile ecolo-gical environment, to construct ecological security patterns so as to effectively avoid the geological disasters, maintain ecosystem health, and promote the coordinated development of regional ecological system and social economic system. Taking Yuxi City as a case study area, this study firstly estimated the ecosystem services importance of water conservation, carbon fixation and oxygen release, soil conservation, and biodiversity according to the basal characteristics of regional ecological environment, and then identified ecological sources in consideration of the quality of integrated ecosystem services and single types. Secondly, the resistance surface based on land use types was modified by the sensitivity of regional geological disasters. Lastly, the ecological corridors were identified using minimum cumulative resistance model, and as a result, the ecological security pattern of Yuxi City was constructed. The results showed that there were 81 patches for ecological sources in Yuxi City, accounting for 38.4% of the total area, and overlaying 75.2% of nature protection areas. The ecological sources were mainly distributed in the western mountainous areas as well as eastern water areas of the city. The length of ecological corridors was 1642.04 km, presenting a spatial pattern of one vertical and three horizontals, and extending along river valleys and fault basins with high vegetation coverage. This paper constructed ecological security patterns in mountainous areas aiming at the characteristics of geological disasters, providing spatial guidance for development and conservation decision-making in mountain areas.

Community composition and diversity of endophytic fungi from the fruits of Pteroceltis tatarinowii.

CHAI Xin-yi, ZHONG Yuan-yuan

2017, 28(2):  636-642.  doi:10.13287/j.1001-9332.201702.016

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Endophytic fungi from the fruit of Pteroceltis tatarinowii were studied, to understand the characteristics of microbial community composition on this ancient and peculiar wild plant. Healthy fruits were collected from areas of the natural distribution of P. tatarinowii in Langyashan Natural Reserve, Anhui Province, China. Endophytic fungi were isolated from fruit tissue, and fungal strains were classified on the basis of morphology. From 500 tissue blocks taken from fruit, a total of 428 isolates of endophytic fungi were identified and classified into 20 genera, 4 families, and 3 orders. Eighty strains showed no reproductive structures, and were classified as Mycelia sterilia (18.7%). The dominant families were Dematiaceae and Sphaeropsidaceae, occupying 38.1% and 32.9% of isolates, respectively. Alternaria and Phomopsis were the dominant genera, accounting for 27.1% and 16.8% of isolates. Different parts of the fruit had different compositions of endophytes. The highest number of fungi was isolated from seeds (19 genera, 181 strains, 42.3%), and the lowest from fruiting wings (7 genera, 88 strains, 20.6%). Alternaria was the commonest genus of endophytes, isolated from three different parts of the fruit. Phomopsis and Macrophoma were the dominant genera on carpopodium and fruiting wings, respectively. The communities on carpopodium and fruiting wings were most similar to one another (C_S=0.78), while those on fruiting wings and seeds were least similar (C_S=0.50). Fisher’s exact test showed no significant difference between the compositions of endophytes from the carpopodium and fruiting wings, while significant diffe-rences were observed between communities on seed and carpopodium, and seed and fruiting wings.

Degradation of quinclorac by corncob, bamboo charcoal, canola meal adsorption-sodium alginate immobilized Pseudomonas stutzeri PFS-4

ZHANG Ke, CHEN Qiang, CHEN Wei, CHEN Jia, GE Sang, LUO Hong-bing

2017, 28(2):  643-650.  doi:10.13287/j.1001-9332.201702.003

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To enhance the degradation of quinclorac in soil and water, corncob, bamboo charcoal, canola meal and sodium alginate were used as complex carriers to immobilize previously isolated bacterial strain Pseudomonas stutzeri PFS-4. Orthogonal experiment was conducted to optimize immobilization condition, and the degradation efficiency of quinclorac by immobilized bacteria and free bacteria in water and soil were further investigated. The results indicated that the optimal conditions for immobilization were: alginate concentration 4%, proportion of adsorption carrier (corncob: bamboo charcoal: canola meal=1:2:1), calcium chloride 3%, crosslinking time 4 h. Immobilized bacteria and free bacteria could effectively degrade 91.4% and 72.8% of quinclorac (800 mg·L^-1) after 6 d inoculation at 30 ℃ and pH 7.0. The removal rates of quinclorac by immobilized bacteria and free bacteria were affected in actual wastewater and soil treatments, but the quinclorac removal rate remained at 84.2% in soil and 74.3% in water, respectively. The results also demonstrated that the carrier and entrapment media significantly affected the quinclorac removal in soil, and the degradation rate of quinclorac in soil was significantly positively correlated with turnover frequency. Therefore, the approach of corncob, bamboo charcoal, canola meal adsorption-sodium alginate immobilized P. stutzeri PFS-4 possesses application potential in in situ remediation of quinclorac contaminated water and soil due to its buffering to adverse conditions.

Effects of temperature on the growth, development and reproduction of Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudococcidae).

HU Zhong-yu, SHAO Wei-dong, HE Yu-jian, ZHANG Jie-di, XU Zhi-hong

2017, 28(2):  651-657.  doi:10.13287/j.1001-9332.201702.032

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In recent years, Dysmicoccus neobrevipes Beardsley (Hemiptera: Pseudococcidae) is found as one of important alien species in China. For the alien pest, temperature always is a crucial factor on constructing stable population. In this study, the development and reproduction of D. neobrevipes population of pumpkin under different temperatures were investigated. The developmental duration, developmental rate, survival rate and fecundity of D. neobrevipes were compared in the laboratory under the conditions of 17, 20, 23, 26, 29 and 32 ℃, photoperiod 14L∶10D, RH (75±5)%, and the life table of the laboratory population was constructed. The results showed that in 20-29 ℃, the developmental durations of every stage of D. neobrevipes all decreased with the increasing temperature; under 20 ℃, both female and male nymph D. neobrevipes had the longest duration, being 46.95 and 50.26 d, respectively. The female and male nymph D. neobrevipes grew most fast under 29 ℃ (20.28 d) and 32 ℃ (20.70 d). The relationship between the developmental rate and temperature for each stage could be simulated by the quadratic regression. In addition, we found that the temperature could impact the survival rate of D. neobrevipes. The highest survival rate of D. neobrevipes was recorded at 29 ℃ for both female (70.3%) and male (69.3%) nymphs. The developmental threshold temperature of female and male was 13.80 ℃ and 11.61 ℃, and the accumulated temperature of female and male was 491.50 and 388.85 day-degrees, respectively. Both pre-oviposition duration and adult longevity decreased with increasing temperature, and the highest fecundity per female was 442.2 eggs at 29 ℃, and the lowest 111.8 eggs at 20 ℃. The population trend indexes under 20 ℃ and 29 ℃ were 19.1 and 168.2, respectively. At 17 ℃ and 32 ℃, D. neobrevipes of the 1st instar nymphs and 3rd instar nymphs were found to stop growth, suggesting that excessively high or low temperature was unfavorable to the growth of D. neobrevipes. In conclusion, temperature could significantly affect the growth and development, survivorship, reproduction and population increasing of D. neobrevipes, and the most suitable temperature range for this pest is from 23 ℃ to 29 ℃.

Sexual size dimorphism and female individual fecundity of Saurogobio dabryi in the lower reaches of the Jialing River, Southwest China.

HU Yue, ZENG Yu, JIANG Zhao-ming, ZHOU Cai-quan

2017, 28(2):  658-664.  doi:10.13287/j.1001-9332.201702.031

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To investigate the sexual morphological differences and female individual fecundity of Saurogobio dabryi, the sexual size dimorphism, sex ratio and female individual fecundity of 76 individuals collected from the lower reaches of the Jialing River (Hechuan section) in breeding season were analyzed. The results showed that the sex ratio of S. dabryi in the downstream of Jialing River was 1:1 in the breeding season, and no significant difference in the body size between males and females. However, some local morphological traits (such as cephalosome and the truck) exhibited significant difference between males and females, for example, the head, the pectoral fin and the pelvic fin were significantly larger in males than in females, while the width, height and length of trunk exhibited the opposite results, all which were related to the sexual selection. A principal component analysis showed that the first three components accounted for 75.2% of variations in the morphological variables. However, all traits overlapped between males and females, thus they could not be separated by morphological characters. By establishing discrimination function, 92.1% samples could be distinguished. The individual fecundity of S. dabryi ranged from 979 to 19979 eggs, and exhibited significant positive relationship with body length and carcass mass. Compared with the historical data, the fecundities of S. dabryi increased significantly in the present study, which should be the active adaption of the species to the currently depleting population, as well as to the changing of water ecological environment.

Morphological traits of indigenous field carps maintained in traditional rice-based farming systems.

GUO Liang, REN Wei-zheng, HU Liang-liang, ZHANG Jian, LUO Jun, SHEN Hong-guang, YAO Hong-guang, CHEN Xin

2017, 28(2):  665-672.  doi:10.13287/j.1001-9332.201702.033

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Rice-fish is an important traditional farming system. In the rice-fish system, common carp (Cyprinus carpio) is the major species raised in paddy field where the environment is characterized by shadow water. Under a long-term of natural selection and artificial selection, the carp would adapt to the paddy field environment. We investigated two indigenous carps (C. carpio qingtianensis and C. carpio congjiangensis) that originated and evolved in the Globally Important Agriculture Heritage System (GIAHS) ‘rice-fish system’ in Qingtian, Zhejiang Province and ‘rice-fish-duck system’ in Congjiang, Guizhou Province. We measured the morphological traits of indigenous carps by collecting carp samples from ‘rice-fish system’ and ‘rice-fish-duck system’. We used mitochondrial gene (D-loop) to build phylogenetic tree. We also collected data of morphological traits of other carp populations from documented databases and published papers. Both traditio-nal morphometric analysis and landmark based geometric morphometric analysis showed that Qingtian field carp and Congjiang field carp differed in body shape. Compared with Qingtian field carp, Cong-jiang field carp had a longer and more narrow tail, and lower ratio of tail length to body length. The analysis of phylogenetic tree suggested that Qingtian field carp and Congjiang field carp were genetically independent populations. However, principal component analysis basing on morphometric traits showed that the field carps (Qingtian field carp and Congjiang field carp) were morphometrically similar to each other and were both significantly different from other common carp populations, especially in the traits of caudal fin and dorsal fin. All these results suggested that carps living and evolving in paddy field environment were significantly different in genetics and morphology from the carp populations living in other water environment and that Qingtian field carp was morphologically different from Congjiang field carp.

Reviews

Greenhouse gas emissions, carbon leakage and net carbon sequestration from afforestation and forest management: A review.

LIU Bo-jie, LU Fei, WANG Xiao-ke, LIU Wei-wei

2017, 28(2):  673-688.  doi:10.13287/j.1001-9332.201702.004

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Forests play an important role in climate change mitigation and concentration of CO₂ reduction in the atmosphere. Forest management, especially afforestation and forest protection, could increase carbon stock of forests significantly. Carbon sequestration rate of afforestation ranges from 0.04 to 7.52 t C·hm^-2·a^-1, while that of forest protection is 0.33-5.20 t C·hm^-2·a^-1. At the same time, greenhouse gas (GHG) is generated within management boundary due to the production and transportation of the materials consumed in relevant activities of afforestation and forest management. In addition, carbon leakage is also generated outside boundary from activity shifting, market effects and change of environments induced by forest management. In this review, we summarized the definition of emission sources of GHG, monitoring methods, quantity and rate of greenhouse gas emissions within boundary of afforestation and forest management. In addition, types, monitoring methods and quantity of carbon leakage outside boundary of forest management were also analyzed. Based on the reviewed results of carbon sequestration, we introduced greenhouse gas emissions within boundary and carbon leakage, net carbon sequestration as well as the countervailing effects of greenhouse gas emissions and carbon leakage to carbon sequestration. Greenhouse gas emissions within management boundary counteract 0.01%-19.3% of carbon sequestration, and such counteraction could increase to as high as 95% considering carbon leakage. Afforestation and forest management have substantial net carbon sequestration benefits, when only taking direct greenhouse gas emissions within boundary and measurable carbon leakage from activity shifting into consideration. Compared with soil carbon sequestration measures in croplands, afforestation and forest management is more advantageous in net carbon sequestration and has better prospects for application in terms of net mitigation potential. Along with the implementation of the new stage of key ecological stewardship projects in China as well as the concern on carbon benefits brought by projects, it is necessary to make efforts to increase net carbon sequestration via reducing greenhouse gas emissions and carbon leakage. Rational planning before start-up of the projects should be promoted to avoid carbon emissions due to unnecessary consumption of materials and energy. Additionally, strengthening the control and monitoring on greenhouse gas emissions and carbon leakage during the implementation of projects are also advocated.

History and distribution of terraced landscapes and typical international cases analysis.

CHEN Die, WEI Wei, CHEN Li-ding

2017, 28(2):  689-698.  doi:10.13287/j.1001-9332.201702.010

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Terracing, developed in those large mountainous areas with high pressure of dense population, is believed as one of the most effective land use approaches. Based on the geographical and climatic differences, the various types of terraces are widely distributed and highly evaluated in terms of ecological and cultural values around the world. Since ancient times, humans have used terracing practices for intensive agricultural production. The main objective of terracing is for mitigating water erosion, stabilizing hill slopes, improving site conditions and crop productivity. During the last decades, agricultural land use in the world has changed considerably. Terraces in many regions were abandoned and had resulted in increasing soil erosion, slope collapse and land degradation along with the socioeconomic development. In this study, through summarizing the origin, history and distribution of terraces in different geographical regions and environmental conditions around the world, we discussed how the different historical and environmental contexts such as climate change, public policy, demographic migration and economic change affected the cycles of terracing construction, usage and abandonment. Aiming at maintaining the sustainable use and mana-gement of terraced fields, further studies regarding water management and terrace maintenance needed to be enhanced.

Impacts of cross-habitat resource subsidies on ecosystems: A review.

ZHANG Yi-xin, XIANG Hong-yong

2017, 28(2):  699-711.  doi:10.13287/j.1001-9332.201702.035

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The flux of matter, energy and nutrients across ecosystems, i.e., resource subsidy, is a fundamental attribute of ecosystems, as well as one of basic research questions in ecology. Common subsidies include leaf litter and terrestrial insects that fall into waters, the adults of aquatic insects, spawning salmon. The allocthonous input of resource subsidy can influence individual organisms, populations, communities, biodiversity and ecosystem functioning, such as enhancing individual growth, increasing species abundance and diversity, affecting community structure, enhancing secondary productivity, influencing food-chain length and food web. Due to increased human impacts on environments, especially at aspects of land use, climate change and invasive species, the influence of anthropogenic disturbance on cross-ecosystem resource subsidies will be intensified at both spacial and temporary scales, so that ecosystems will face severer threats. Accordingly, future ecological researches in this field should emphasize the following aspects: impacts of single and multiple stressors on subsidies and ecosystems, implementation of dynamic resource subsidies on ecosystem restoration and management, the dark sides of subsidy relating with pollutants, and basic ecological research on cross-ecosystem resource subsidy in tropics and sub-tropics, as well in China.

Effects of spatial structure on predator-prey interactions: A review.

DONG Hong-juan, WU Xin-wei, WANG Hong-jiao, XIA Shan-shan, PAN Ying

2017, 28(2):  712-720.  doi:10.13287/j.1001-9332.201702.040

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With increasing human disturbances (e.g., spatial fragmentation), drastic changes have taken place in spatial structure, which further affects the structure and function of ecosystem. The consequences of spatial changes on ecological processes are significantly associated with change in predator-prey interactions. Thus, exploring the relationships between spatial structure andpredator-prey interactions was of significance in understanding the underlying mechanisms of ecological changes in fragmented landscapes. This paper summarized current studies about the effects of typical spatial structures on predator-prey interactions, including the spatial size, spatial shape, spatial orientation, spatial distribution and spatial connectivity. Researches indicated that the stability and continuation of predator-prey system generally decreases with decreasing spatial size and connectivity, and excessive increase in the fragmentation of space, as well as changes in spatial shape and orientation which result in excessive increase in the grazing rate of predators. Effect of complicated spatial structure (coupled from above-mentioned structures) on predator-prey interactions, especially multispecies predator-prey interactions, should be focused on in the future.