江西快三

 江西快三关于本刊影响因子及获奖投稿须知订阅及广告专辑与专题学术会议绿色发表通道优秀论文 
   
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Volume 40,Issue 11
  • Habitat suitability assessment of Marco Polo sheep in Taxkorgan Nature Reserve in Xinjiang
  • Authors:LI Meiling, CHEN Qiangqiang, HAN Lei, WANG Peng, YANG Jianwei, WANG Muyang, YANG Weikang
  • Abstract:Marco Polo sheep is a representative species in Pamir Plateau. Habitat suitability assessment is of great significance for the protection and management of the species. In this study, three groups of parameters including biological, non-biological factors, and the human interference were considered comprehensively. With help of ArcGIS, the habitat suitability index model was used to compare and analyze the potential and valid habitat areas and habitat loss rates at different scales, as well as the changes of habitat suitability in different seasons. The results showed that the potential suitable habitat areas within the reserve was 2127.19 km2 in summer and 1915.70 km2 in winter, respectively. The potential suitable habitat areas within the actual distribution area in the northwest area of the reserve was 1095.48 km2 in summer and 1072.82 km2 in winter. Therefore, the suitable habitats for the Marco Polo sheep were mainly distributed within the actual distribution area. With the human interference, the suitable habitat loss rates within the reserve were 18.43% in summer and 17.78% in winter, 33.65% in summer and 29.73% in winter within the actual distribution area. The results showed that human activities have a greater impact on the actual distribution area, so we should focus on protecting it. In conclusion, the key impact factors were the National Road G314 and grazing activities. Four suggestions and ideas are proposed for the habitat protection of the Marco Polo sheep and the management and planning of the reserve.
  • DownLoad:Habitat suitability assessment of Marco Polo sheep in Taxkorgan Nature Reserve in Xinjiang.PDF
  • The temporal and spatial changes of temperature in Black-necked Crane over wintering area of Yarlung Zangbo River
  • Authors:WANG Tao, SHEN Weishou
  • Abstract:Based on temperature data of 13 meteorological stations in the upper and middle reaches of the Yarlung Zangbo River during 1980-2015, the annual and winter temperature changes of black-necked cranes overwintering area in the middle and upper reaches of the Yarlung Zangbo River were studied. The results showed that from 1980-2015, the annual average temperature, the annual average maximum temperature, and the annual average minimum temperature of the wintering area presented a very significant increase trend. The amplitude of the interannual fluctuation of the wintering period was relatively larger than the annual average temperature. Among them, the highest temperature increase rate during the winter season was the fastest, and the annual warming rate was higher with 0.09℃/10a. The trend of annual temperature in wintering and temperature increase in wintering period were consistent at the spatial level. The cyclical changes in average temperature, maximum temperature, and minimum temperature during the wintering period were earlier than the whole year, and there was a two-year periodic oscillation. During the wintering period, the average temperature, the average maximum temperature, and the average minimum temperature were mutated during the statistical period. The years of mutation were 1995, 1998, and 1993. There was no sudden change in daily range of temperature, and the temperature in winter and the temperature in winter were abrupt. In addition to the daily range of temperature, the direction of sudden changes in temperature during winter and winter temperatures is a sudden change from cold phase to warm phase.The long-term monitoring of climate change in the black-necked cranes overwintering area, reaches of the Yarlung Zangbo River, is of great significance for analyzing and accurately identifying the impact of climate change on the overwintering of black-necked cranes distribution area habitat and strengthening the protection of overwintering area of black-necked cranes.
  • DownLoad:The temporal and spatial changes of temperature in Black-necked Crane over wintering area of Yarlung Zangbo River.PDF
  • Effects of Père David deer (Elaphurus davidianus) grazing on soil physicochemical properties
  • Authors:AN Yuting, LIU Bin, WANG Libo, XIE Shengbin, XUE Dandan, WU Yongbo
  • Abstract:The physicochemical properties of soil was directly affected by grazing and trampling of animal. In order to explore the main factors affecting soil physical and chemical properties by Père David deer grazing, parameters including water content, bulk density, salt content, organic matter, total N, P and K contents under different intensity of semi-free Père David deer disturbance were analyzed. The fieldwork was conducted in Dafeng Père David deer National Nature Reserve, Jiangsu province, China. The results indicated that (1) the contents of soil water and organic matter were negatively correlated with the increase of the grazing intensity. However, the contents of soil salt content, total N, P and K contents were positively correlated with the increase of grazing intensity. (2) The soil physicochemical properties parameters between the heavy grazing and the control plots showed significant differences (P<0.01). (3) The maximum value of total N, P and K contents was 1.56 g/kg, 0.95 g/kg and 13.43 g/kg in heavy grazing area, respectively. Especially, N content was the most remarkable parameter. (4) The soil salt content was up to 9.26 g/kg in heavy grazing area. Soil salinization was the main reason causing the habitat degradation in Dafeng nature reserve. The increasing of grazing intensity led to soil salinization and habitat degradation. The heavy salinized soil degenerated to bare land gradually.
  • DownLoad:Effects of Père David deer (Elaphurus davidianus) grazing on soil physicochemical properties.PDF
  • Spatio-temporal variation of land surface water and heat fluxes over karst city
  • Authors:WANG Xiuxin, TANG Guyun, LUO Lianling, SUN Tao, ZHU Qijiang
  • Abstract:In order to study thermally environmental problems caused by rapid expansion of Guilin city in Southwest China karst area in the last 20 years, the METRIC model was improved for suitability of the actual situation in karst cities. Then land surface water and heat fluxes were retrieved with the improved METRIC model from five Landsat images from1994 to 2015. Finally, the spatio-temporal variations of the fluxes were analyzed. The results showed that the land cover types with the values of latent heat flux from the highest to the lowest were water body, vegetation on the sunny slopes of karst hills, ground vegetation, vegetation on the shady slopes of karst hills, buildings and roads, bare soil, and bare rock on karst hills. In contrast, the land cover types with the values of sensible heat flux from the highest to the lowest were bare rock on karst hills, buildings and roads, bare soil, vegetation on the sunny slopes of karst hills, ground vegetation, vegetation on the shady slopes of karst hills, and water body. The temporal variations of land surface water and heat fluxes were influenced by the changes of land covers. The ratio of sensible heat flux to latent heat flux, defined as Bowen ratio, was 1.62 in 1994 as the highest, down to 1.24 in 2000, and gradually rising to 1.51 in 2015. The area proportions of the high sensible heat flux and the low latent heat flux resulted from urban expansion were less than 10.0%. The above area proportion changes resulted in the changes of the area proportions of the middle, low sensible heat flux and middle, and high latent heat flux. The area proportion of the high sensible heat flux was with the highest 10.0% in 1994, went down to 5.4% in 2000, and gradually rised to 9.4% in 2010. But it dropped to 7.1% in 2015. The variation trend of the area proportions of the low latent heat flux is essentially the same with that of the high sensible heat flux. While vegetation fraction ranges between 0.1 and 0.8, it affected the fluxes very obviously. The value of sensible heat flux decreased 8-27 W/m2 and the value of latent heat flux increased 8-24 W/m2 with the 0.1 rise of vegetation fraction. Vegetation protection on karst hills and ground greening construction are crucial in improving urban heat environment in karst cities.
  • DownLoad:Spatio-temporal variation of land surface water and heat fluxes over karst city.PDF
  • Analysis of the wetland ecological pattern in Wuhan City from the perspective of ecological network
  • Authors:HE Jianhua, PAN Yue, LIU Dianfeng
  • Abstract:Urban wetland plays the important role of ecological guarantee in urban sustainable development. In recent years, urban wetland has become more fragmented due to the accelerated urbanization, which severely threatened the security of wetland system. Ecological network is a kind of effective landscape organization which connects important habitat patches through corridors. Compared with the landscape indexes, the analysis of urban wetland system based on ecological network is beneficial to reveal the characteristics of landscape connectivity. We took Wuhan City as our study area and used the morphological spatial pattern analysis (MSPA) method to identify the wetland sources. Considering the influence of landscape types, slope and human activity intensity, we constructed a comprehensive resistance surface to reflect the degree of obstruction when species spread between the wetland patches. The minimum cumulative resistance (MCR) model was adopted to establish the wetland ecological network. We classified the corridors according to their connectivity importance. Finally, we analyzed the structural and regional characteristics of wetland ecosystem in Wuhan. The results show that: the amount of wetland resource in Wuhan is large, but it's seriously fragmented and distributed unevenly. The wetland ecological network has a suitable landscape structure for the effective circulation of ecological processes. Most of wetland corridors are located between patches near the edge of Wuhan, especially in the south of the city. The characteristics of wetland system vary greatly in different regions. Jiangxia and Hannan have abundant wetlands and corridors, in which wetland patches are also of high quality. Their corridors have good landscape structures but are not very important for wetland connectivity. The wetlands in Huangpi and Dongxihu have little quantity and broken shape. The corridors in these two districts are few and of low importance, and their landscape structures also need to be improved. The amount of wetlands and corridors in Xinzhou are both inadequate, and the corridors are important for maintaining wetland connectivity while their landscape structures are not good enough. The results could provide scientific basis for the protection and construction of Wuhan wetlands.
  • DownLoad:Analysis of the wetland ecological pattern in Wuhan City from the perspective of ecological network.PDF
  • Comprehensive assessment method on ecological patch importance: a case study in Sichuan Province, China
  • Authors:LIU Yimeng, YANG Saini, NI Wei, HE Jinbiao
  • Abstract:Ecological patches provide places for the survival and development of species. Urbanization processes have led to a sharp area decline of ecological patches and severe fragmentation, which seriously threaten ecosystem services. Ecological patch importance assessment can help identify the key regions of maintaining landscape connectivity. It is an effective way to achieve efficient ecological protection and hierarchical management. Based on network modeling and topological indicators, and combined with TOPSIS and ordered sample clustering, we evaluated and ranked the ecological patch importance in Sichuan Province in 2015 from the perspective of landscape connectivity. The results show that the ecological patches in Sichuan Province were relatively continuous in the northwest, while they were scattered and sparse in the south and east. The comprehensive assessment method can effectively rank patch importance and patches can be divided into five importance levels. The high-level ecological patches were mainly located at core area, while low-level patches were distributed at the edge of the province. We proposed corresponding planning suggestions according to the characteristics of ecological patches at different levels, aiming at guiding local ecological planning from a holistic perspective. The results provide references for the optimization of metapopulation protection at a provincial scale with limited resources.
  • DownLoad:Comprehensive assessment method on ecological patch importance: a case study in Sichuan Province, China.PDF
  • Uncertainty analysis and risk management of ecological risk of urban landslide disaster: a case of Shenzhen City
  • Authors:WU Jiansheng, LUO Yuhang, WANG Xiaoyu, ZHAO Yuhao
  • Abstract:The rapid urbanization along with intensive construction activities, strongly changes the natural landform and the stable geological environment, which leads to increasingly frequent landslide disasters. Taking Shenzhen as the research area in this study, the ecological risk of street scale landslide disaster was evaluated based on the three-dimensional evaluation framework "Risk-Vulnerability-Potential loss". The visual risk structure of "three primary colors" was applied while the uncertainty analysis was carried out by Monte Carlo simulation. Then the ecological risk management measures were proposed. The results show that: (1) There was a significant negative correlation between the uncertainty and the evaluation area. As the evaluation area increased, the uncertainty of ecological risk sources decreased. (2) For the ecological risk assessment where risk source is the main uncertainty, the uncertainties are jointly determined by the ecological risk source uncertainty and the value of the extrinsic factor which is the sensitive factor of the ecological risk uncertainties. (3) The ecological risk of landslide disaster in Shenzhen presents a structure of "low-high-low-high" from west to east. The risk structures are mainly of the "high vulnerability-high potential loss" type and the "high risk-high potential loss" type. The analysis of ecological risk structure, the establishment of an ecological risk management system for landslide disaster and the development of clear risk management objectives are conducive for the effective management of ecological risk.
  • DownLoad:Uncertainty analysis and risk management of ecological risk of urban landslide disaster: a case of Shenzhen City.PDF
  • Land development suitability evaluation for sustainable urban ecosystem management-Taking Yantai as an example
  • Authors:WANG Jing, ZHAI Tianlin, ZHAO Xiaodong, SONG Ziqiu, YUAN Xinyi, KONG Xuesong
  • Abstract:The suitability evaluation of land development is the basis and premise for the preparation of territorial spatial planning. This study is to explore an evaluation method and application for resources-environment carrying capacity and land development suitability toward to sustainable urban ecosystem management. Based on the "bottom line" thinking of ecological protection red line and permanent basic farmland, this study proposed a logical framework and index system for evaluation of resources and environment carrying capacity and land development suitability with background constraint-integrated restriction-capacity evaluation-multi-space suitable evaluation. Taking Yantai as an example, this study set up different scenarios of urban ecosystem protection, and comprehensively used Delphi method and multi-element space overlay method to carry out the study of evaluation of resources and environmental carrying capacity and land development suitability. The results showed that: (1) The restriction of resource and environment to Yantai's economic and social development was weak, and the areas with high-restriction only accounted for 6.09% of land area. (2) The resources and environmental carrying capacity varied greatly among different districts and counties in Yantai, showing a gradually increasing trend from the northwest to the southeast. (3) Under the scenario of sustainable urban ecosystem management, there were significant differences in the land development suitability for urban land use. The suitable construction area was only 2380 km2. Under the scenarios of traditional management of urban ecosystem, the suitable construction area of Yantai was 2610 km2. The quantity structure of unsuitable construction area and suitable construction area was 1.12:1. Yantai had great potential in the development and utilization of land space. In both scenarios, the suitable construction area in Yantai City was larger than the current construction area, which provided land security for the future development and ensured the water resources security and ecological security. The results can provide decision-making information support and technical services for the optimization of land space in Yantai, as well as major decision-making and strategic deployment of government departments in relevant regions.
  • DownLoad:Land development suitability evaluation for sustainable urban ecosystem management-Taking Yantai as an example.PDF
  • Spatial distribution patterns of three sympatric Tomicus species initially infesting Pinus yunnanensis trunks
  • Authors:WU Chengxu, ZANG Lipeng, ZHANG Sufang, KONG Xiangbo, LIU Fu, ZHANG Zhen, LI You, XU Fangling, HUANG Guiying
  • Abstract:Three bark beetles, Tomicus minor, T. yunnanensis and T. brevipilosus, are distributed in southwest China and mainly infest Pinus yunnanensis, causing serious damage to forestry production. In order to study the effect of the relationship of coexistence among three sympatric Tomicus species on their spatial distribution, the spatial distribution patterns of different degrees of infestation in the trunk were analyzed with geostatistical and traditional aggregation index methods. The results showed that the population density of T. yunnanensis was significant higher than that of T. minor in the heavily infested stand, contrary to the lightly infested stand. The results from the traditional index method showed that the spatial distribution patterns of three sympatric Tomicus species were all aggregated in the different degrees of infestation stands. The aggregation distribution of T. minor and T. yunnanensis resulted from their aggregation behavior and environment. The results from the geostatistical method showed that all presented the aggregation distribution, in addition to T. brevipilosus in the heavily infested stand. The level of spatial dependence of all populations ranged from 4.01 to 7.45 m, except the T. minor population in the heavily infested stand. The semivariogram models of T. minor and T. yunnanensis switched between a spherical model and a gaussian model. In short, the coexistence of three sympatric Tomicus species in different population densities did not affect their spatial distribution patterns, but impacted the semivariogram models and model parameters.
  • DownLoad:Spatial distribution patterns of three sympatric Tomicus species initially infesting Pinus yunnanensis trunks.PDF
  • Simulating the response of biomass accumulation process in semi-arid grassland to changes in precipitation
  • Authors:WANG Mingming, LIU Xinping, HE Yuhui, WEI Jing, Chelmge, SUN Shanshan
  • Abstract:Horqin Sandy Land is one of the serious desertification areas in north China. Understanding the response of the sandy grassland biomass accumulation to precipitation changes is beneficial to the ecological restoration and ecosystem management for this area. In our study, we simulated the response of vegetation biomass accumulation process to precipitation change in the growing season of Horqin sandy grassland on point scale by combining the vegetation-soil water coupling model and the vegetation Threshold-Delay response model (T-D). The results revealed that (1) the accumulation of vegetation biomass was improved with the increase of precipitation, and otherwise inhibited with the decrease of precipitation. However, under the same degree of change in precipitation, the response of biomass accumulation to the increase of precipitation was far greater than the response to the decrease of precipitation, which revealed that there was a significant nonlinear responding relationship between the accumulation of vegetation biomass and the change in precipitation. (2) The response of biomass accumulation to change in precipitation frequency was significantly positively correlated with the change of single effective precipitation in both dry year and wet year, weakly correlated with the change of cumulative effective precipitation, and significantly correlated with change in effective precipitation interval only in dry years. This result showed that the change of precipitation frequency in different precipitation years actually affects the accumulation of biomass by changing the single effective precipitation and effective precipitation interval. (3) Vegetation biomass accumulation process had obvious response threshold to precipitation frequency change, and this response thresholds were different under different precipitation amount and precipitation characteristics. In all, there was obvious response of biomass accumulation to precipitation change, and the combination of vegetation-soil moisture coupling process model and T-D model can effectively identify this response on daily scale, which provided a new tool for exploring the relationship between vegetation and precipitation.
  • DownLoad:Simulating the response of biomass accumulation process in semi-arid grassland to changes in precipitation.PDF
  • Comparison of changes in flowering phenology of woody plants and temperature sensitivity between Xi'an and Baoji
  • Authors:TAO Zexing, GE Quansheng, XU Yunjia, WANG Huanjiong
  • Abstract:Plant phenology is an important indicator of ecosystem response to climate change. Most of the previous studies used the phenological observation data from the representative sites to investigate the phenological characteristics and its responses to climate change. Whether the phenological changes and their sensitivity to temperature are consistent among different sites of the same climatic region needs further exploration. This study selects Xi'an and Baoji, which are distributed at the Fen-Wei Plains climatic region with a humid and temperate climate, as the study area. Using the data of the first flowering date (FFD) and end of flowering date (EFD) of 21 woody plants in Xi'an and Baoji from China Phenological Observation Network, the interannual change and temperature sensitivity of flowering phenology were compared at different sites during 1987-2016. The results showed that the FFD and EFD of most species advanced in Xi'an and Baoji over the past 30 years. For most species, the trend of FFD in Xi'an (mean: -0.57 days/year) was significantly stronger than that in Baoji (mean: -0.29 days/year), but there was little difference in the trend of EFD between the two sites. Except for Lagerstroemia indica and Jasminum nudiflorum, the temperature sensitivity of the FFD and EFD for other species presented no significant difference between the two sites. Thus, the phenological changes at a single site cannot reflect the phenological changes in the whole climatic region, because the changes in FFD always showed significant discrepancies among different sites due to divergent changes in temperature. However, the temperature sensitivity of FFD and EFD calculated at a single site could well reflect the plant phenology-climate relationship at other sites in the same climatic region. Our study could provide a scientific basis for the analysis of regional phenological changes and responses to climate change using phenological observation data from the limited sites.
  • DownLoad:Comparison of changes in flowering phenology of woody plants and temperature sensitivity between Xi'an and Baoji.PDF
  • Vegetation coverage dynamics in northern slope of Tianshan Mountains from 2001 to 2015
  • Authors:QI Yaxiao, ZHANG Fei, CHEN Rui, WANG Yishan
  • Abstract:Vegetation plays an important role in global environmental change. Monitoring the dynamics change of vegetation coverage is critical to a region's ecological security. With the development of 3S technology, vegetation monitoring becomes more convenient and effective. This study used MODIS NDVI data of the month (June-September) when vegetation grew vigorously from 2001 to 2015 in northern slope of the Tianshan Mountains, combined with dimidiate pixel principle to extract the vegetation coverage. Linear regression, coefficient of variation and other methods were used for the analysis of vegetation coverage dynamics. The results showed that: (1) The annual average vegetation coverage in the study area ranged from 0.4 to 0.5 in June-September, while vegetation coverage grade were mainly at low and low-medium levels. (2) During 2001-2015, the vegetation coverage tended to increase gradually and the proportion of vegetation improvement area (54.42%) was larger than that of the degraded area (45.58%). The vegetation improvement was more obvious in the west than in the east. The variation types of vegetation coverage were mainly weak variation and moderate variation, and the major change type of vegetation coverage was stable type. (3) The change of vegetation coverage in northern slope of the Tianshan Mountains was obviously affected by altitude. The proportion of lower vegetation coverage showed an increased-decreased-increased trend, while that of higher vegetation coverage was on the contrary. Low vegetation coverage in area above 3880 m occupied an absolute dominant position. (4) The area weighted gravity centers of vegetation coverage at different levels were concentrated in Shawan, Shihezi, Manas and Hutubi, which showed a trend from concentration to relative dispersion.
  • DownLoad:Vegetation coverage dynamics in northern slope of Tianshan Mountains from 2001 to 2015.PDF
  • Effect of nitrogen addition with different chemical forms on dynamics of photosynthate using 13CO2 tracing in an alpine grassland
  • Authors:SONG Minghua, CHEN Jin, JIANG Jing, WANG Feng, YU Feihai
  • Abstract:Long-term exzogenous nitrogen (N) input into terrestrial ecosystems causes changes in carbon storage in plant and soil pools. However, little is known how input of N with different chamical forms could influence patterns of photosynthetic carbon (C) allocated into dofferent pools, such as above- and below-ground plant tissues, soil, and soil respiration. In particular, the mechanisms underlying changes in plant and soil carbon storage in responses to N input are not clear. A long-term fertilizaiton experiment of N with different chemical forms was carried out in an alpine meadow on the Tibetan Plateau. We tested the patterns of photosynthetic carbon allocated into plant tissues, soil, and soil respiration using 13C tracing experiment in the field. Our results showed that N input with different chemical forms caused changes in the patterns of photosynthetic C allocated into above- and below-ground plant tissues. Moreover, allocation of photosynthetic C into soil differed in response to different chemical forms of N, and the C-CO2 fluxes were significantly different regarding to the N chemical forms. Specifically, significant differences in patterns of photosynthetic C allocated into different pools were found between ammonium-N and nitrate-N treatments. Comparison with ammonium-N, relatively faster transition of photosynthetic C was found in nitrate-N treatment, and photosynthetic C was fastly respired via soil respiration. The results from 13C labeling are corresponding to the significantly high carbon stored in plant root and soil in ammonium-N than in nitrate-N treatments. Our results showed that aboveground biomass in ammonia-N treatment were 49.5% higher than that in the control treatment as N addition treatments have been performed for 10 years. Meanwhile, belowground biomass in ammonia-N treatment were 111.3% higher than that in the control treatment. The 13C retained in the soil showed a downward trend during the 30 days, and the soil carbon pool in ammonia-N treatment was significantly higher than that in nitrate-N treatment. The 13C efflux from soil respiration with time followed an exponential decay function in each one of the treatments. Among them, decay rate of 13C in nitrate-N treatment was the fastest one. On the first day after 13C isotope labeling, 13C in plant shoots was ammounted to about 80% of the 13C in the shoots after the immidiate labeling. There was no significant difference in 13C in plant shoots on the first day after labeling between different treatments. On the 30th day, the retention of 13C in shoots was reduced to about 30% of the initial amount. The values in nitrate-N treatment were significantly lower than those in the control and ammonia-N treatments from day 21 to 30. The results showed that the photosynthetic C fixed by plants was rapidly transported into underground tissues and soil in a short period of time in the treatment of nitrate-N addition. Our results illustrate the responses of allocation in photosynthetic C to N input with different chemical forms. We also quantified the rate of C-CO2 efflux via soil respiration, which is critical to understand clearly about the contribution of photosynthetic C to soil carbon stroage. The results can be used to develop more resonable policy in grassland management, which are benefial for sustable development of the alpine grasslands.
  • DownLoad:Effect of nitrogen addition with different chemical forms on dynamics of photosynthate using 13CO2 tracing in an alpine grassland.PDF
  • Leaf N and P resorption characteristics of typical tree species in the Ziwuling forest area on Loess Plateau
  • Authors:DENG Jian, CHONG Yujie, JIA Xiaomin, JIAO Ziyi, REN Chengjie, HAN Xinhui, YANG Gaihe
  • Abstract:In order to reveal the nutrient resorption characteristics of the main tree species of different succession stages and vegetation types in Ziwuling forest area on Loess Plateau, we selected four secondary succession forest tree species (Quercus wutaishansea Mary, Pinus tabuliformis Carr., Betula platyphylla Suk., and Populus davidiana Dode) and two artificial forest tree species (Robinia pseudoacacia L., and Platycladus orientalis (L.) Franco). The C, N and P concentrations of soil, green leaves, and senesced leaves were determined, and the N and P resorption efficiency (NRE and PRE) and C:N:P stoichiometry ratios were calculated. The results showed that (1) the soil and leaves nutrients were significantly different among different tree species.The soil C and N contents and C:N:P stoichiometry ratios showed the order of late succession stages forests (Quercus wutaishansea Mary and Pinus tabuliformis Carr.) > early succession stages forests (Betula platyphylla Suk. and Populus davidiana Dode) > artificial vegetation forests (Robinia pseudoacacia L. and Platycladus orientalis (L.) Franco). (2) The NRE and PRE of different tree species was 17.18%-43.34% and 27.13%-58.12%, respectively, with the order of late succession stages forests > artificial vegetation forests > early succession stages forests. The PRE were mostly higher than the NRE. (3) The NRE and PRE showed stronger relationship with leaves nutrient than with soil nutrient, and also showed stronger relationship with C:N:P stoichiometry ratios than with C, N and P concentrations. It indicated that N and P resorption was an important mechanism for typical tree species in the Ziwuling forest area to adapt to nutrient limitation, especially for the late succession stages forests. This can provide basis for vegetation restoration in the Loess Plateau.
  • DownLoad:Leaf N and P resorption characteristics of typical tree species in the Ziwuling forest area on Loess Plateau.PDF
  • Relationship between vein density and leaf nitrogen concentration of Dodonaea viscose in response to habitat changes in rocky desertification area, Wenshan, Yunnan
  • Authors:CHEN Jing, ZHUANG Lihui, MU Jianhua, ZHOU Jiansong
  • Abstract:Changes of vein traits and leaf nitrogen concentration of plant affect the formation of leaf economic spectrum, which provides a theoretical basis for verifying the construction of leaf vein network function in leaf structure. The mass-based nitrogen content (Nmass) and area-based nitrogen content (Narea) were used as leaf nitrogen concentration in this study. Principal component analysis and linear regressions were used to determine the relationships of vein density with leaf nitrogen concentration of Dodonaea viscose in three natural habitats. The study area was located in the rocky desertification area in Dongshan Township, Wenshan City, Yunnan (23°54'N, 104°58'E). According to the light condition of forest community, D. viscosa population was divided into 3 microenvironments including open areas of forest (I), forest edge (II), and forest understory (III). We sampled 10 (10 m×10 m) D. viscose plots from each microenvironment and investigated photosynthesis of the plants and environmental factors at three gradients. Three individuals of D. viscose were selected in each plot. The leaf area, leaf dry weight, chlorophyll content, vein density (VD), Nmass and Narea of 12 healthy leaves from 4 directions in each individual were measured at laboratory. The results indicated that specific leaf area, total chlorophyll content, light use efficiency, and Nmass of D. viscosa increased gradually along the gradient from I to III in arbor-shrub community, while the light saturation point, light compensation point, water use efficiency, VD, and Narea decreased gradually. The net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance, and photosynthetic nitrogen use efficiency increased firstly and then decreased. There were varying correlations between VD and leaf nitrogen content. VD was significantly negatively correlated with Nmass (P<0.05), but had a significantly positive correlation with Narea in I and III (P<0.05). The correlation was not significant between VD both Nmass and Narea in II (P>0.05). In the open areas of forest habitats, which were characterized by strong light intensity, D. viscosa had a higher VD, Narea and lower Nmass than those growing on forest edge and forest understory habitats. While the opposite patterns were seen in the shady habitats, reflecting the strong leaf vein plasticity of plants in rocky desertification areas and its balance mechanism with nitrogen utilization traits.
  • DownLoad:Relationship between vein density and leaf nitrogen concentration of Dodonaea viscose in response to habitat changes in rocky desertification area, Wenshan, Yunnan.PDF
  • Nutrient distribution and biochemical cycling in different aged moso bamboo (Phyllostachys pubescens) ecosystems
  • Authors:XIA Chuange, NING Chen, LUO Zhaohui, DENG Xiangwen, YAN Wende, TIAN Dalun
  • Abstract:Moso bamboo (Phyllostachys pubescens) is an important forest resource in southern China. The conversion from mixed bamboo and broad-leaf forest to pure bamboo forest may cause a potential degradation of soil fertility in pure bamboo plantations. Therefore, understanding the productivity and biochemical cycling process of bamboo forests is vital for maintaining the sustainability. In this study, we investigated nutrient allocation and biochemical cycling patterns in different aged (1 year, 3 years, and 5 years) bamboo forests. The age category was based on the age distribution of the individual bamboo in one forest site, which accounted for more than 50%-60% of the total individuals. Our results showed that the mean tissue concentrations of N and K were the highest in all the bamboo forests, whereas Ca and P were the lowest. The nutrient concentrations also varied in different organs nested in different aged stands of bamboo. Additionally, the nutrient contents varied in different dead floor layer among different aged stands or even in a same aged stand. N, P, and K in soil decreased with soil depth, while Ca content increased. The accumulated nutrients ranged 338.31-1104.72 kg/hm2 in the whole forest ecosystem, 37.69-46.94 kg/hm2 in dead floor, and 56952.67-63783.22 kg/hm2 in soil layers, respectively. The nutrient cycling index ranged from 237.41-338.30 kg hm-2 a-1 for annual absorption, 20.84-86.47 kg hm-2 a-1 for annual return, and 216.57-267.05 kg hm-2 a-1 for annual retention, respectively. The nutrients utilization coefficient was 0.27-1.00, 0.09-0.25 for cycling coefficient, and 6.17-40.33 years for recycling period, respectively. Our results indicated that bamboo forests had relatively high absorption, low return, and high retention of nutrient elements on an annual basis. Thus, more nutrients are needed and advanced scientific management is required in order to maintain a long-term productivity of bamboo forests comparing to other common forest types in this area.
  • DownLoad:Nutrient distribution and biochemical cycling in different aged moso bamboo (Phyllostachys pubescens) ecosystems.PDF
  • Effects of endophytic bacteria on proline and malondialdehyde of wheat seedlings under salt stress
  • Authors:XU Yajun, ZHAO Longfei, XING Hongfu, LUO Yunxiao, WEI Zhengxin
  • Abstract:Taking Zhoumai 18 as research materials, 252 and 254 as tested strains, wheat treatment group with salt stress, bacterial treatment group, and the control group used by artificial climate culture method were cultivated for 7d, 14d, and 21 d. The content of proline (Pro) and malondialdehyde (MDA) of wheat seedlings treated with inoculation and those of wheat under salt stress were determinated. The results showed that Pro content of salt stress group firstly rose then falled with the increase of culture time and salt concentration under salt stress environment. In the prophase and metaphase, contents of wheat Pro under salt stress gradually accumulated and improved the resistance of wheat. In the anaphase, Pro contents declined to certain degrees compared with those in metaphase, which indicated that wheat gradually adapted to salt environment. With increasing salt concentrations, wheat in various groups of salt stress exhibited different levels of resistances to salt environment at different stages of cultivation. During each period, there was a threshold of wheat resistance to salt concentration. When salt concentration was greater than such threshold, Pro content declined, and wheat resistance to salt was lessened. After inoculation with endophytes, higher Pro content of wheat improved the ability of wheat resistance to salt stress, and its respair effect of 14 d was the most obvious. When the treatment group inoculated with 252 and 254 respectively under the concentration of salt, their Pro content were higher 133.48% and 91.48% for 200 mmol/L and 250 mmol/L than those of salt stress group. MDA content of wheat with salt stress group was first drop and rose with time prolong, but Pro content changes had inverse trend. During the prophase and metaphase, in various groups of salt stress, lipid peroxidation degrees of wheat cellular membrane were not high, which brought about no severe threat to the normal metabolism of wheat. During the anaphase, MDA content increased and wheat in various groups of salt stress gradually withered. Due to the accumulation of reactive oxygen species in cells, some ingredients would be involved in severe reactions. After inoculation with endophytes, endophytes reduced the degree of lipid peroxidation of wheat cellular membrane, enhanced the survival rate of wheat, and promoted the growth of wheat seedlings. MDA content were lower than that on the 21d in salt stress group, and remediation effect was significant.
  • DownLoad:Effects of endophytic bacteria on proline and malondialdehyde of wheat seedlings under salt stress.PDF
  • Responses of photosynthetic characteristics and chlorophyll fluorescence parameters of Phoebe zhennan saplings to cadmium stress
  • Authors:TIE Dexiang, HU Hongling, YU Xiuyan, SHU Yijia, ZHANG Jian
  • Abstract:Using 3.5 a saplings of Phoebe zhennan as experimental materials, the response of photosynthetic physiology and chlorophyll fluorescence parameters of P. zhennan under different concentrations of cadmium (Cd) stress was investigated by pot experiment.A total of 6 Cd (CdCl2) treatment levels (0, 10, 20, 30, 40, 50 mg/kg) were set up, and the application amount of each treatment was divide into 5 equal parts and each part was applied once every two months., the photosynthesis and photosynthetic physiological indicators were measured as soon as the experiment was over. (1) With the aggravation. of Cd stress, the total amount of chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Car) decreased, and Chla/b gradually increased. (2) The net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) decreased significantly with the aggravation of stress, while the intercellular carbon dioxide concentration (Ci) increased. (3) With the enhancement of cadmium stress, the light saturation point (LSP) and the dark respiration rate (Rd) all showed a downward trend, and the light compensation point (LCP) gradually increased. (4) Initial fluorescence (F0), maximum fluorescence (Fm), actual photon efficiency (ΦPSII), electron transfer rate The ETR and photochemical quenching coefficient (qP) decreased with the increase of cadmium stress, and the non-photochemical quenching coefficient (qN) increased gradually. As for the maximum photochemical efficiency (Fv/Fm) and PSII potential activity (Fv/F0), there was no significant change at T1-T4, and it was significantly increased at T5. (5) The dissipation of residual light energy of seedlings was mainly based on the pathway of heat dissipation, but with the increment of cadmium concentration(T3-T5), the dissipation of non-chemical reaction energy (Ex) increased, and the heat dissipation energy (D) and photochemical reaction energy (P) decreased. The photosynthesis of P. zhennan saplings were severely inhibited under low concentration of Cd(T1-T2) stress. With the further increase of Ca concentration (T3-T4), the chlorophyll fluorescence parameters changed significantly. The distribution of light energy has changed significantly, indicating that the cadmium tolerance of P. zhennan saplings is weak, so it is necessary to pay attention to the site selection for young plantation of P. zhennan,and in particular, to avoid to plant it in place where cadmium pollution is serious.
  • DownLoad:Responses of photosynthetic characteristics and chlorophyll fluorescence parameters of Phoebe zhennan saplings to cadmium stress.PDF
  • Effects of tea polyphenols on physiological characteristics in leaves of wheat seedlings under salt stress
  • Authors:SI Lianbang, LI Jiamin, LI Guiying, JIANG Xiaoyu, Lü Lirong, YANG Yingli
  • Abstract:Soil salinization, which can affect plant growth and agricultural output, is one of the worldwide environmental problems. The salt environment may impair chloroplast structure and decrease photosynthetic pigment content, thereby affecting the photosynthetic efficiency of plants. It may also alter the production of reactive oxygen species and thus affect the physiological characteristics in plants. Extracted from tea, tea polyphenols (TP) is an anti-aging, anti-tumor and anti-bacterial substance. It is mostly employed in animal research, but there are few studies on its effect on plant stress. Wheat cultivar Longchun 30 seedlings were used in present research to explore the effects of 150 mmol/L NaCl and different TP concentrations, in case of being applied or in combination, on such physiological characteristics as chlorophyll content, chlorophyll fluorescence characteristics and hydrogen peroxide (H2O2) generation. The results were follows: 1) 150 mmol/L NaCl treatment alone decreased chlorophyll content, actual light quantum yield [Y(II)], photochemical quenching (qP) and photosynthetic electron transfer efficiency (ETR) in wheat leaves, but improved non-photochemical quenching (NPQ). However, these indicators did not alter in response to TP treatment alone. 2) Salinity treatment resulted in the stimulation of cell wall-POD (cw-POD), diamine oxidase (DAO) and polyamine oxidase (PAO); low TP concentration significantly increased the activity of cw-POD, but did not have remarkable effects on DAO and PAO activities; in contrast, high TP concentration did not affect cw-POD activity, but significantly inhibited DAO and PAO activities. 3) Compared with NaCl treatment alone, the application of TP and NaCl in combination led to the increases of chlorophyll content, maximal photochemical efficiency (Fv/Fm) and ETR of photosystem II (PS II) in salinity-stressed seedlings, but the decreases of NPQ value, H2O2 content and the activities of cw-POD, DAO and PAO. In conclusion, while effectively alleviating the reduction of chlorophyll content and the inhibition of PSII photosynthetic electron transport rate and photochemical reaction rate in response to salinity stress, TP significantly reduced cw-POD, DAO and PAO activities as well as the incidence of H2O2 generation, thereby alleviating the damage on wheat seedlings caused by salt stress and improving their tolerance to salt environment.
  • DownLoad:Effects of tea polyphenols on physiological characteristics in leaves of wheat seedlings under salt stress.PDF
  • Effects of southwest hilly areas's purple soil acidity on the growth and photosynthetic characteristics of Sapindus mukorossi Gaertn saplings
  • Authors:TIAN Qiuling, YUE Jiaxing, WU Jiaojiao, ZHANG Wen, GAO Lan, QIAN Chun, LIU Yun
  • Abstract:Sapindus mukorossi Gaertn. (Indian soapberry) is an important tree species with many economic and ecological applications. In recent years it has been widely planted in poor mountainous areas of southwest China in association with forest restoration programs. At the same time, purple soil acidification due to excess use of fertilizers has increased in the southwest hilly areas and this has impacted the growth of S. mukorossi. Photosynthesis leads to creation of plant organic matter which tends to accumulate, but when photosynthetic capacity declines there are progressive impacts on soil quality. Studying the responses of photosynthesis and growth of S. mukorossi to acid soil stress will provide a theoretical basis for effective planting. We conducted soil acid stress experiments using randomized block experimental design in a purple soil acidic region of Chongqing. Three-year-old saplings were examined growing in soils having different degrees of acidity (pH 4.4, 5.6 and 7.6). The effects of soil acidity on growth, leaf traits and photosynthesis were analyzed. The results showed that the contents of soil available nitrogen (AN) and available phosphorus (AP) in the neutral zone were significantly lower than those in the acidic zone, and the contents of total nitrogen (TN) and total potassium (TK) in the leaves of the neutral zone were significantly higher than those in the acidic zone (P<0.01). Compared with neutral soils, in acidic regions the height of saplings, net photosynthetic rate of leaves (Pn), total chlorophyll content (Chls), chlorophyll a (Chl a), carotenoid (Cars), and ratio of chlorophyll a/chlorophyll b (Chl a/b) were significantly lower (P<0.01). The maximum photochemical efficiency of PSⅡ(Fv/Fm) and the PSⅡnon-photochemical fluorescence quenching coefficient (qN) were also lower (P<0.05). In addition, the content of chlorophyll b (Chl b) and the ratio of chlorophyll/carotenoid (Chls/Cars) were significantly higher (P<0.01). Crown width, PSⅡelectron transfer rate(ETR), PSⅡ photochemical fluorescence quenching coefficient(qP) and actual primary light capture efficiency (Y(II)) also increased (P<0.05). In strongly acidic soil, the light saturation point (LSP) of leaves was significantly lower (P<0.01), while the apparent quantum yield(AQY), light compensation point (LCP) and dark respiration(Rd) were the highest. AQY, LCP and Rd were lowest in the weakly acidic soil. Ground diameter, specific leaf area (SLA), leaf area (LA), stomatal conductance(Gs)and transpiration rate(Tr)of the experimental saplings in the weakly acidic soil were the highest among the three experimental soils, and significantly higher than in the strongly acidic soil (P<0.05). The acidity of purple soil significantly reduced the photosynthetic capacity of S. mukorossi. in acidic region by affecting soil nutrient transformation and root absorption capacity. The saplings in weak acidic region showed strong ecological adaptability owing to increasing light energy capture area, increasing photosynthetic electron transfer rate and light energy capture efficiency of PS II, and reducing organic matter consumption. We conclude that the suitable range of pH values for planting Sapindus mukorossi in purple soil regions of Chongqing was 5.5-7.5, while growth was poor when planted in purple soil with pH less than 5.5.
  • DownLoad:Effects of southwest hilly areas's purple soil acidity on the growth and photosynthetic characteristics of Sapindus mukorossi Gaertn saplings.PDF
  • Analysis of microbial community structure and diversity of saline soil in Gudahu Wetland
  • Authors:YU Shaopeng, SHI Chuanqi, HU Baozhong, DING Junnan, MENG Bo, YANG Chunxue
  • Abstract:The original, woodland, cultivated land and lakeshore saline soil microbe of Gudahu wetland in Heilongjiang Province was selected as study object. Using the high-throughput sequencing method, we analyzed soil bacterial and fungal community structure and diversity of the four habitat types. Combining soil physicochemical index, the impact of soil environmental factor on the microbe community diversity was further analyzed. The results showed that Proteobacteria was with the highest relative abundance value in bacterial communities and Ascomycota had the highest relative abundance value in fungal communities. The bacterial community diversities were similar while the fungal were different in the same habitat; however, each of them was different in different habitats. The cultivated land soil bacterial community diversity was similar to that of woodland soil, but was closer to that of lakeshore soil. Cultivated land soil and woodland soil were with higher bacterial community diversity, followed by original soil, Lakeshore soil was with the lowest bacterial community diversity. Cultivated land soil and lakeshore soil had higher fungal community diversity, followed by original soil and woodland soil. Comparing to fungi, the diversity of bacterial community was more affected by soil environmental factors, and both pH value and moisture could significantly influence the bacterial and fungal community diversities.
  • DownLoad:Analysis of microbial community structure and diversity of saline soil in Gudahu Wetland.PDF
  • The influence of vegetation coverage on soil erosion in sandstone loess area
  • Authors:BAI Xuelian, ZHENG Haiying, WANG Lixiang, JI Shuxin, CHEN Zhengxin, CHANG Xueli
  • Abstract:Soil erosion is one of the most serious soil degradation problems in the world. Its abnormally occurrence, development and change process directly affect the development and utilization of water and soil resources. Meanwhile, it threatens human survival, social and economic development. Numerous studies have shown that the increased vegetation coverage was a main factor to reduce soil erosion. It was an important issue attracted much attention of researchers in soil and water conservation that the quantitative relationship between vegetation coverage and soil erosion in different research areas in the world. Ten Turbutries located in northern Ordos is one of the most serious soil erosion areas, which was mainly distributed by moderate and severe erosion area, and covered by sandstone loess. In our study, the soil erosion modulus was calculated using Universal Soil Loss Equation (USLE) based on remote sensing technique, rainfall, DEM and land use/cover data. Then, the relationship between vegetation coverage and soil erosion modulus was analyzed by the method of overall fitting and sectional fitting regression to identify the vegetation coverage corresponding to the threshold of soil erosion modulus. The results showed that the annual average soil erosion modulus was 29.31 t hm-2a-1 from 2000 to 2017. The largest in 2016 and the smallest in 2011 were 65.6 t hm-2a-1 and 10.95 t hm-2a-1, respectively. The change trend of soil erosion modulus was a typical parabolic curve (P<0.001). When the slope grades were <5°, 5-10°, and > 10°, the threshold of soil erosion modulus were18.18 t hm-2a-1, 34.29 t hm-2a-1 and 74.56 t hm-2a-1, and the corresponding vegetation coverage were 11.42%, 16.51% and 16.5%, respectively. In the sandstone loess area, the soil erosion modulus not only would be affected by the factors in USLE model, but also limited by the amount of soil erodibility. In addition, it should be paid great attention to the years with large amount of erosion when judging the relationship between soil erosion and vegetation coverage in regional scale.
  • DownLoad:The influence of vegetation coverage on soil erosion in sandstone loess area.PDF
  • Effects of different recovery years on the ecological stoichiometry characteristics of soil carbon, nitrogen and phosphorus in riparian farmland: a case study of Wenyu River
  • Authors:GUO Erhui, FANG Xiao, MA Li, YANG Xiaoyan, YANG Xitian
  • Abstract:Abandoned farmland is the secondary succession of soil and vegetation toward the natural direction. Studying the eco-stoichiometric characteristics of carbon, nitrogen and phosphorus in riparian soil of the abandoned farmland is one of the important scientific bases for restoring and rebuilding the degraded riparian ecosystem caused by farmland disturbance. Taking the riparian farmland as the control, this paper studies the impacts of different abandonment years (2 years, 8 years, and 10 years) on soil carbon, nitrogen, phosphorus contents and their interrelationships in the riparian zone. The results showed that (1) the soil organic carbon and nitrogen content presented abandonment of 10 years > abandonment of 8 years > abandonment of farmland > abandonment of 2 years. The soil phosphorus content was in order of abandonment of 10 years > abandonment of 8 years > abandonment of 2 years > farmland. The soil carbon, nitrogen and phosphorus content of farmland and abandonment years decreased with the increase of soil depth. However, the difference of soil carbon and nitrogen was more significant than that of phosphorus. (2) The average values of C/N and C/P in riparian soils showed a trend of abandoning for 10 years, farmland, 8 years and 2 years. The mean values of N/P were as follows: abandonment for 10 years (0.78) > farmland (0.77) > abandonment for 8 years (0.77) > abandonment for 2 years (0.67), which indicated that N was the limited nutrient element for vegetation restoration in riparian zone of the study area. (3) There was a significant coupling linear relationship between C and N contents in riparian farmland and soils with different abandonment years, but the linear fitting degree between C and P, N and P was relatively low. (4) At the initial stage of abandonment succession (2 years), the soil bulk density did not change significantly, but with the increase of abandonment time (8 years and 10 years), the soil bulk density decreased significantly and soil structure improved.
  • DownLoad:Effects of different recovery years on the ecological stoichiometry characteristics of soil carbon, nitrogen and phosphorus in riparian farmland: a case study of Wenyu River.PDF
  • The process of soil desiccation under artificial shrub and grass in northern Loess Plateau
  • Authors:LIU Bingxia, REN Jian, SHAO Ming'an, JIA Xiaoxu
  • Abstract:The water-wind erosion crisscross region, located in northern Loess Plateau, is a typical ecologically fragile area. Soil desiccation occurs frequently under artificial shrubs and grass. The formation of dried soil layer (DSL) affects eco-hydrological cycle and threatens vegetation construction and ecological stability. To understand the soil desiccation process under artificial shrub and grass and to determine their suitable planting years, dynamics of soil water content and aboveground biomass with growth year for caragana and alfalfa were analyzed in the Liudaogou catchment. The results showed that soil water was consumed strongly and decreased rapidly under 2-8-year old caragana and 1-7-year old alfalfa. After then, soil water was relatively stable, changing slightly between 8.2%-9.0% under caragana and 8.5%-10.5% under alfalfa, respectively. The DSL was develop at depth of 1-1.4 m under 4-5 year-old caragana. The DSL reached 2.4 m depth, and the thickness of the DSL was 1.4 m under 6 year-old caragana. The depth of DSL exceeded 4.0 m under 9-12 year-old caragana. There was no desiccation under 2-4 year-old alfalfa, however, the DSL reached at 3.6 m depth and the thickness was 2.6 m at the end of growing season for 5 year-old alfalfa. The depth of DSL exceeded 4.0 m after 7 year-old alfalfa. Therefore, in order to decrease the risk of DSL formation, it is suggested that the growth years of caragana and alfalfa should not exceed 6 and 5 years, respectively. Their corresponding maximum dry biomass is about 5050 kg/hm2 for caragana and 1980 kg/hm2 for alfalfa, respectively. The results can provide scientific basis for management of artificial vegetation and regulation of DSL in northern Loess Plateau.
  • DownLoad:The process of soil desiccation under artificial shrub and grass in northern Loess Plateau.PDF
  • Effects of soil moisture on Phragmites australis leaves and soil C, N and P ecological stoichiometric characteristics in Yangguanwetland, Dunhuang
  • Authors:LIU Dong, ZHANG Jian, BAO Yalan, ZHAO Haiyan, CHEN Tao
  • Abstract:Soil moisture is one of the key factors affecting the strategies of plant nutrient uptake and utilization in arid region. Studies on leaf and soil ecological stoichiometry characteristics under different soil moisture gradients are helpful to reveal the response and ecological adaptability of plants to environmental changes. Through field investigation and experimental analysis, reed leaves and soil C, N, P ecological stoichiometric characteristics under different soil moisture gradients and their relationships in the Yangguan wetland of Dunhuang were studied. The results showed that: (1) with the increase of soil moisture content, the contents of leaf C, N and P showed a decreasing trend, while leaf C/N, C/P, and N/P showed the opposite trend; (2) with the increase of soil moisture content, the content of soil organic carbon (OC),total nitrogen (TN), total phosphorus(TP), and N/P increased, soil C/N ratio decreased and soil C/P first increased and then decreased; (3)under the low soil moisture gradient, N and C/N of leaves were significantly negative correlated with soil N and C/N(P<0.05), and leaf C, P, C/P, N/P had no significant correlation with soil C, P, C/P, and N/P (P>0.05). There was no significant correlation between the soil and leaf stoichiometric characteristics under the high and medium soil moisture gradients (P>0.05). Leaves under low soil moisture gradient, which were restricted by drought stress and soil nutrients, could maintain higher leaf nutrient content, reflecting the unique nutrient regulation mechanism of wetland plants under heterogeneous habitats in arid areas.
  • DownLoad:Effects of soil moisture on Phragmites australis leaves and soil C, N and P ecological stoichiometric characteristics in Yangguanwetland, Dunhuang.PDF
  • Effects of short-term fertilization on soil fungal community structure and functional group in Eucalyptus artificial forest
  • Authors:CHEN Zujing, GAO Shangkun, CHEN Yuan, HE Pinghui, HE Qian, QIU Quan, LI Jiyue
  • Abstract:In order to investigate the response characteristics of the soil fungal community to short-term fertilization in Eucalyptus artificial forest, Illumina high-throughput sequencing and FUNGuild platforms were performed in this study. The soil fungal community composition, functional groups and their impact factors were analyzed under the short-term fertilization and non-fertilization (control, CK) treatments. As the result shown, Basidiomycota and Ascomycota were identified as the dominant fungi at the class level, accounting for 48.61%-46.74% and 39.31%-38.08%, respectively. The soil fungal community at the class level was not significantly changed by short-term fertilization. On the order level, the relative abundance of (23.73%) and Eurotiales (19.95%) was significantly increased by 7.65 and 1.72 times under the fertilization treatment, respectively, when compared with CK treatment. However, the ratios of Archaeorhizomycetales, Onygenales, Tremellales, and other dominant orders were obviously decreased in soil under the fertilization treatment. The alpha diversity and abundance index of soil fungi were slightly decreased under the fertilization treatment. Meanwhile, the principal coordinate analysis indicated that the fungal community composition was significant difference between the fertilization and CK treatments. Spatrotroph group was identified as the most dominate trophic group in the soil of Eucalyptus artificial forest. The ratio of symbiotroph group was significantly increased by 4.19 times under the fertilization treatment when compared with CK treatment. In addition, the ectomycorrhizal fungus Pisolithus was mainly increased in the symbiotroph group, whereas the relative abundance of other trophic group fungi was obviously decreased. Moreover, the redundancy analysis showed that the soil fungal community was mainly influenced by the soil factors including the contents of soil available nutrition, soil organic carbon, microbial biomass carbon, pH value, and soil moisture. Our results indicated that the short-term fertilization treatment altered the soil fungal community structure and functional group in Eucalyptus artificial forest, and also increased the proportion of symbiotic fungi and improved the soil quality.
  • DownLoad:Effects of short-term fertilization on soil fungal community structure and functional group in Eucalyptus artificial forest.PDF
  • Research on zooplankton diversity using DNA-based metabarcoding technique: a case study in the Yalvjiang Estuary
  • Authors:GAO Yangchun, LI Haitao, WANG Xiaocheng, SUN Yi, ZHAN Aibin, Aileen TAN Shau-Hwai, LI Hongjun
  • Abstract:In order to assess the power of DNA-based metabarcoding in the monitoring of marine biodiversity, we ultilized both metabarcoding technique and morphological method to compare communtiy diverstiy of copepods, which were collected from 22 sites along the Yalvjiang Estuary of China. The results showed that: (1) a total of four order, 23 family, 32 genus and 229 operational taxonomic units (OTUs) were detected through the metabarcoding technique, whereas only three order, five familiy, five genus and six species were identified based on the morphological method. In addition, most taxonomic categories (100% order, 80% family, and 80% genus) identified based on the morphological method could be also detected using the metabarcoding technique. Reversly, however most taxonomic categories (25% order, 83% family and 88% genus) detected using the the metbarcoding technique could not be identified based on the morphological method. The results suggested that the metabarcoding technique was more powerful than the morphological method in the assessment of copepod diversity. (2) The variation of diversity index based on the metabarcoding method was significantly consistent with the morphological method (r=0.542, P=0.024), suggesting good comparability between the two methods. Our results indicated that the DNA-based metabarcoding technique had high application potential in efficient assessment of marine biodivesity.
  • DownLoad:Research on zooplankton diversity using DNA-based metabarcoding technique: a case study in the Yalvjiang Estuary.PDF
  • Comparative study on the suitability of periphytic algae and phytoplankton in river health assessment
  • Authors:LIU Yuanyuan, AYI Qiaoli, ZHANG Senrui, WU Xingrong, WAN Binna, ZHANG Xiaoping, ZENG Bo
  • Abstract:Algae are sensitive to the changes of water environment. The species composition and individual quantity of algae are closely related to the living environments and change with environmental variation. Therefore, algae are usually used as an indicator to assess river health. Aquatic algae can be divided into periphytic algae and phytoplankton according to their inhabiting behaviors. In previous studies, some researchers applied phytoplankton in river health assessment, but some other researchers applied periphytic algae in river health assessment. However, as regards which of periphytic algae and phytoplankton is more suitable in river health assessment, or whether no significant difference exists in the suitability of periphytic algae and phytoplankton in river health assessment, very few studies have been reported so far. In this study, taking Jialing River and Wujiang River as the subject, 11 sections in total were set in these two rivers, and the physi-chemical characteristics of water environment and the periphytic algal and phytoplankton communities at 11 sections were investigated in September, 2015. By using periphytic algal index of biological integrity (Pe-IBI) and phytoplankton index of biological integrity (Ph-IBI), together with comprehensive pollution index (CPI), the health status of Jialing River and Wujiang River were assessed. It was shown in this study that seven core parameters including total algal taxa number, Cyanophyta taxa number, Chlorophyta taxa number, individual proportion of Nitzschia, individual proportion of dominant taxa, Shannon-Wiener's diversity index, and evenness index, could be screened when the Pe-IBI was applied in the health assessment of Jialing River and Wujiang River. The negative correlations of Pe-IBI to CPI, total nitrogen content, and lead content of river water were found, which means that the biological integrity of periphytic algae decreased with the deterioration of water environment. However, when the Ph-IBI was applied in the health assessment of Jialing River and Wujiang River, only one core parameter (algae density) could be screened. Moreover, no correlation of Ph-IBI to comprehensive pollution index or to any of twelve water environmental factors was found. Our study revealed that, for rivers, periphytic algae is better than phytoplankton to indicate the water environmental quality, and consequently, periphytic algae is more suitable than phytoplankton to be used in river health assessment.
  • DownLoad:Comparative study on the suitability of periphytic algae and phytoplankton in river health assessment.PDF
  • Management strategy for biodiversity conservation to adapt to climate change in China
  • Authors:LI Haidong, GAO Jixi
  • Abstract:Addressing climate change and conserving biodiversity are two major globally environmental hotspots. Climate change brings a series of new challenges for biodiversity conversation, while it threatens the spatial pattern of ecological security and sustainable development in the ecologically fragile areas in China. Climate change could lead to species diversity loss, decline of ecosystem service, and damage of regional ecological security zone. Therefore, doing the risk management of biodiversity conservation to adapt to climate change is not only a necessary measure for biodiversity adapting to climate change risks, but also an important way to mitigate climate change. In this paper, we firstly investigated the related technical policies of biodiversity conservation to adapt to climate change issued by developed countries such as the European Union, Australia, and the United States, and the progress of China's biodiversity addressing to climate change, combining with implementation progress of Aichi Biodiversity Targets 10. Secondly, we analyzed the problems of China's biodiversity conservation to adapt to climate change. They included 1) the scientific cognition of biodiversity addressing climate change needed to be improved; 2) insufficient capacity building for biodiversity conservation to adapt to climate change; 3) lack of ecological corridor networks for adaptation to climate change among nature reserves; and 4) lack of technical standards for biodiversity conservation to adapt to climate change. Finally, strategies were put forward to adaptive management of biodiversity addressing climate change. Specifically, the countermeasures included developing the National Programme for China's Biodiversity Conservation to Cope with Climate Change, strengthening capacity building of biodiversity conservation to adapt to climate change, carrying out pilot projects for adaptive management of nature reserves to deal with climate change risks, as well as strengthening the scientific and technological support on biodiversity addressing climate change. These could provide a decision-making basis for promoting biodiversity conservation incorporating risk management of climate change.
  • DownLoad:Management strategy for biodiversity conservation to adapt to climate change in China.PDF
  • Analysis on the structure characteristics of virtual elements trading network in major crops trade of China
  • Authors:HAN Xue, LIANG Xuan, WANG Qian
  • Abstract:We divide virtual elements into two types: virtual resource elements and virtual ecological elements. The virtual farmland elements represented the former and virtual fertilizer/pesticide elements represented the latter; these elements are selected as our research objects. We quantitatively analyzed the trade volume of the virtual elements to establish the trade network. Our research used complex network methods to focus on the total trade volume of virtual farmland and fertilizer/pesticide elements of major agricultural products in China from 2002 to 2016. The results showed downward trends of 25.51% and 8.01% for the farmland and fertilizer/pesticide elements, respectively. The areas of the virtual farmland network with a higher degree of in-node were the middle and lower reaches of the Yangtze River, South China, and Southwest China, while the areas with the higher degree of out-node were Huanghuaihai and Northeast China. The dynamics of the network of virtual fertilizer/pesticides show a clear opposite trend. The node strengths of the virtual elements varied greatly, with a maximum of 14.5956 million hectares and 613,800 tons for the farmland and fertilizer/pesticide elements, respectively. The cumulative distribution of both the node degree and node strength conform to a power law relationship; the "heavy-tailed" phenomenon reveals a high variability of node degree and node strength and the fragility of the network structure. The network of input areas of virtual farmland element are assortative and the output areas are disassortative; specifically, the flow of virtual farmland between regions is both agglomerated and dispersed. The correlation degree of the virtual fertilizer/pesticide element network is a reduction function, and the network is disassortative; this indicates that the flow of virtual fertilizer/pesticide is close between the eight regions. The network structure analysis lays the foundation for studying the invulnerability, optimization, and control mechanism of the network while providing a theoretical basis for a pattern of the grain trade, the establishment of grain prices, and an adjustment of the agricultural planting structure in various regions of China.
  • DownLoad:Analysis on the structure characteristics of virtual elements trading network in major crops trade of China.PDF
  • Origin and evolution of biodiversity hotspots in Southeast Asia
  • Authors:TAN Ke, Pastor L. Malabrigo, REN Mingxun
  • Abstract:Southeast Asia has the largest archipelagos and probably has the most complex geological history in the world. The overwhelming monsoon climate further promotes the extremely rich biodiversityin Southwest Asia. A large number of primitive taxa of angiosperms including Austrobaileyales and Nymphaeales were found in this region. Several tropical groups such as Cyrtandra, Aeschynanthus, and Begoniaare distributed in Southeast Asia, especially in Borneo Island and Indo-China Peninsula. Thus, Southeast Asia is not only a ‘museum’ of early angiosperms, but also acts as an ‘evolutionary front’ for some tropical taxa. Based on the plant distribution pattern, climate, and geographic history, the whole of Southeast Asia can be divided into four phytogeographic regions, i.e., Indo-China Peninsula (a part of Indo-Burma hotspot), the Sundaland (including Malay Peninsula, Borneo Island, Sumatra Island and their adjacent islands), the Wallacea (Philippines, Sulawesi Island, Java Island, Lesser Sunda Islands, Moluccas Islands), and the New Guinea. The Wallacea experiences obvious dry-wet seasonal changes in one year due to strong effects of monsoons, while Sundaland and New Guinea are wet for the whole year. Indo-Burma was connected with Sundaland during the glacial periods and acted as a ‘land bridge’ for plant dispersal in Asia, Australia, and the Pacific. Consequently, Southeast Asia became a crossroad for long-distance dispersal of modern angiosperms. Borneo and Indo-China Peninsula are the evolutionary hotspots for the whole of Southeast Asia and act as ‘species source’, while the Java Island and Lesser Sunda Islands are mainly ‘species pool’as most species on these islands are immigrants from nearby regions. For a better understanding of the species dispersal history and the formation of phytogeographic regions in Southeast Asia, the updated molecular technologies should be used, and the plant taxa should be sampled in the entire distribution range in future studies.
  • DownLoad:Origin and evolution of biodiversity hotspots in Southeast Asia.PDF

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