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Volume 37,Issue 2
  • An indicator system for biodiversity and ecosystem services evaluation in China
  • Authors:FU Bojie, YU Dandan and LÜ Nan
  • Abstract:Assessment of biodiversity and ecosystem services can provide important base for ecosystem management and decision making. Indicator systems are major tools for scientific assessments. However, no unified indicator systems and methods have been developed for evaluation of biodiversity and ecosystem services in China. It brings poor comparability of evaluation results among different regions and some difficulty in regional and national integration studies. Therefore, it is urgent to establish a scientific, systematic, standard indicator system for evaluation of biodiversity and ecosystem services in China at present. In this paper, we propose the principles of establishing evaluation indicator system, and establish an indicator system for biodiversity and ecosystem services evaluation in China on the basis of the main research outcome in biodiversity and ecosystem services and the cascade relations of biodiversity-ecosystem structure-process and function-ecosystem services.
  • DownLoad:An indicator system for biodiversity and ecosystem services evaluation in China.PDF
  • Indicator systems and methods for evaluating biodiversity and ecosystem services
  • Authors:YU Dandan, LÜ Nan and FU Bojie
  • Abstract:Evaluating, simulating, and predicting the status and trends of biodiversity and ecosystem services, as well as their impacts on human well-being, are currently the primary goals for researchers in the field of biodiversity and ecosystem services, and indicators and data models and scenarios are major tools for the theoretical and methodological integration of biodiversity and ecosystem services. However, few detailed studies have conducted comprehensive analyses or comparisons of indicator systems or reported methods for evaluating biodiversity and ecosystem services. In this paper, we review recent work regarding the conceptual framework, indicator systems, and various types of models and methods related to the assessment of biodiversity and ecosystem services. The biodiversity-ecosystem function-services-human well-being cascade model is a more expressive logical framework, and owing to various problems and challenges, existing indicator systems and methods are ineffective for elucidating the mechanisms that determine the formation and impact of ecosystem services, for identifying internal connection and function mechanisms among services, or for offering guidance for ecosystem service management and policy making. However, existing indicator systems and methods provide an important entry point for constructing a synthetic evaluation model. Through a comprehensive analysis and comparison of current indicator systems and methods, we propose several core elements for studies of synthetic evaluation models, including i) Objectives, determining the scientific problems and developing schemes for ecosystem services management and decision making by scenario analysis based on the fundamental characters of interactions between nature and society; ii) Content, the comprehensive analysis of scales, service types, hierarchical nature of biodiversity, relationship among the components, drivers, and multi-source data; and iii) Methods, conducting comparison and uncertainty analyses of various types of models and model combinations, in order to establish a comprehensive map-making model base system that is suited for regional analyses. Accordingly, we propose that China should develop a standard indicator system and a synthetic evaluation model of biodiversity and ecosystem services that is suited to the nation's regional characteristics as soon as possible, in order to periodically evaluate, simulate, and predict the status and trends of biodiversity and ecosystem services and to enhance China's position and power of discourse in the international arena of this field.
  • DownLoad:Indicator systems and methods for evaluating biodiversity and ecosystem services.PDF
  • Effects of external carbon on the key processes of carbon cycle in a terrestrial ecosystem and its microbial driving mechanism
  • Authors:HE Yunlong, QI Yuchun, PENG Qin, DONG Yunshe, GUO Shufang, YAN Zhongqing, WANG Liqin and LI Zhaolin
  • Abstract:External carbon input to soil influences the available carbon content and the microbial carbon cycle, as well as the microbial utilization of other nutritional elements in the terrestrial ecosystem. With globally increasing nitrogen deposition, the nitrogen content of soil in some regions has changed significantly and now exceeds microbial demand. This in turn increases the need for available carbon. Therefore, artificial regulation of available carbon sources might be essential for relieving microbial carbon limitation and improving carbon sequestration capacity of terrestrial ecosystem. In this paper, previous studies concerning the influences of external carbon input on soil carbon emission, litter fall decomposition, soil carbon pools, and the functional microbial mechanisms in these processes were reviewed. This work will provide a reference for improving the carbon sink capacity of terrestrial ecosystems.
  • DownLoad:Effects of external carbon on the key processes of carbon cycle in a terrestrial ecosystem and its microbial driving mechanism.PDF
  • Effects of different ecological restoration patterns on labile organic carbon and carbon pool management index of desertification grassland soil in zoige
  • Authors:PU Yulin, YE Chun, ZHANG Shirong, LONG Gaofei, YANG Lirong, JIA Yongxia, XU Xiaoxun and LI Yun
  • Abstract:The changes of soil labile organic carbon and Carbon pool management index (CMPI) under different ecological restoration patterns can provide valuable information for evaluating the effects of ecological restoration measures on soil quality improvement, and screening optimized ecological restoration patterns on desertification forest and grassland. In this study, soil labile organic carbon fractions and CPMI were investigated by applying field investigations and laboratory analyses to desertification grassland receiving different patterns of ecological restoration in Zoige. Three main ecological restoration patterns were used to control desertification of grassland in Zoige, including shrub-grass intercrop pattern I (stripe Tamarix ramosissima incteropping herbs, such as Poa pratensis, Elymus nutan and Ajuga lupulina, SGI), shrub-grass intercrop pattern II (circular Tamarix ramosissima incteropping herbs, such as Poa pratensis, Cremanthodium reniforme, Cirsium japonicum, Daucus carota and Vicia sepium, SGII), and the sand-barrier plus shrub-grass intercrop pattern (the sand-barriers of Tamarix ramosissima plus Tamarix ramosissima incteropping herbs, such as Tamarix ramosissima, Poa pratensis, Elymus nutan, Ajuga lupulina, Daucus carota, SBSG).The results showed that the values of soil organic carbon and its labile fractions contents were higher in the three ecological restoration grasslands than in the desertification grassland without ecological restoration measures (DG). Compared to the DG, the contents of soil microbial biomass carbon (MBC), dissolved organic carbon(DOC), easily oxidized organic carbon(EOC), and particulate organic carbon(POC) in whole profile under the SGI pattern were increased by 36.6%, 139.0%, 89.4%, 130.9%, respectively, and those in the SGII pattern were increased by 2.7%, -43.9%,15.0%,49.7%, respectively, and those in the SBSG pattern were increased by 82.4%,21.8%,56.2%,170.3%, respectively. This indicated that the ecological restoration patterns of SGI and SBSG were similarly effective at improving soil organic carbon, and both were superior to the SGII pattern. The distributed proportions of soil active organic carbon between the three ecological restoration and desertification grassland were difference, for instance the distributed proportion of DOC presented a vertical fractionation in the SGI pattern. The values of CPMI under three ecological restoration patterns were exceeded 100%. This implied that soil quality can be improved by the three ecological restoration patterns, and the order of the improved level was SGI (CPMI, 182.5%) > SGII (CPMI, 157.1%) > SBSG (CPMI, 129.9%). The results suggest that soil easily oxidized organic carbon can be used as an optimized index to reflect changes of soil quality in different ecological restoration grasslands, and soil CPMI can be used to characterize the improved effectiveness of ecological restoration measures on soil quality.
  • DownLoad:Effects of different ecological restoration patterns on labile organic carbon and carbon pool management index of desertification grassland soil in zoige.PDF
  • Influence of grazing exclusion on soil organic carbon and nitrogen mineralization in semiarid grasslands of the Loess Plateau
  • Authors:WANG Yuhong, MA Tian'e, WEI Yanchun, WEI Xiaorong, SHAO Ming'an, CHENG Jimin and ZHANG Xingchang
  • Abstract:Grazing exclusion is an important method for rehabilitating degraded ecosystems in grassland-dominated parts of the semiarid region. However, how ecosystem processes respond to this rehabilitation has not been assessed well. For understanding how the carbon and nitrogen cycling in degraded grasslands responds to such grazing exclusions, it is essential to study the distribution and mineralization of soil organic carbon and nitrogen. Field measurements and laboratory incubations of soil (at 0-80 cm depth) from the Loess Plateau's semiarid region were combined to analyze the soil organic carbon and nitrogen distribution and mineralization after various years of grazing exclusion. Samples were collected from grasslands where grazing was excluded for 17, 22, and 27 years, respectively. As a control, additional soil samples were collected from continuously grazed grasslands that neighbored the grazing exclusion ones. Organic carbon and nitrogen contents, as well as organic carbon and nitrogen mineralization rates, were measured. The effects of grazing exclusion on the distribution of organic carbon and nitrogen mainly occurred in the top 0-40 cm of the soil. Grazing exclusion significantly increased soil organic carbon and nitrogen content, with the largest increases being observed after 17 years of exclusion. However, beyond 17 years, the effects on organic carbon and nitrogen distribution became weaker with time. Furthermore, although for all treatments organic carbon mineralization rates decreased with soil depth, for grazing excluded grasslands the organic carbon mineralization ratio (Cmin/C0) increased more with soil depth. The grazing exclusion effects on mineralization rate were independent of exclusion years or soil layers, in contrast to the effects on Cmin/C0, which did correlate with both these factors. In addition, nitrification and mineralization rates of nitrogen decreased with soil depth, whereas in contrast, the ammonification rate increased. At 0-40 cm soil depth, nitrification rates ranged between 1.5 and 2.5μg g-1 d-1, and ammonification rates between -1.6 and 0.1 μg g-1 d-1. This indicates a nitrification dominated nitrogen mineralization in this soil layer. At 40-80 cm depth, nitrification and ammonification rates ranged between 1.3 and 1.8μg g-1 d-1, and between 0.7 and 0.8μg g-1 d-1, respectively, suggesting that nitrification and ammonification contributed similarly to nitrogen mineralization in deeper soils. Furthermore, grazing exclusion significantly increased the mineralization rate of nitrogen in the 0-40 cm layer, while it decreased this in the 40-80 cm layer. The overall nitrogen mineralization ratio (Nmin/N0) also decreased when grazing was excluded. Finally, the mineralization of organic carbon and nitrogen were significantly correlated with the soil organic carbon and nitrogen content, but less so with the soil carbon to nitrogen ratio (C/N). Overall, the results of this study indicate that the turnover of organic carbon and nitrogen in grazing excluded grassland was determined mainly by soil layer, grazing exclusion duration, and soil organic carbon and nitrogen content.
  • DownLoad:Influence of grazing exclusion on soil organic carbon and nitrogen mineralization in semiarid grasslands of the Loess Plateau.PDF
  • The response of soil nutrients (carbon and nitrogen) and extracellular enzyme activities to drought in various cultivation ages from tea orchards
  • Authors:ZHAO Xing, ZHONG Yiming, YANG Jingping, LÜ Yamin and WANG Xiaopeng
  • Abstract:Frequent summer droughts, caused by climate change, have negatively affected the productivity and quality of tea orchard soil. Tea (Camellia sinensis L.) is an important cash crop in southern China, therefore it is important to examine soil nutrients, enzyme activity, and microbial community structural shifts under such summer drought conditions in various cultivation ages. In this study, the pot method was utilized to investigate the soil quality of various cultivation ages of 0, 10, 30, and 50 years. These pots were incubated at 25℃ and given two different water treatments (30% and 55% WFPS (water-filled pore space)). Throughout the incubation period, soil samples were taken to measure the soil carbon, nitrogen content, and extracellular enzyme activities at 0, 7, and 14 days. The results indicated that prior to the incubation period, nitrate nitrogen, ammonia nitrogen, microbial nitrogen, and the total organic carbon in the soil increased with cultivation age. The microbial carbon and the extracellular enzyme activities (β-1,4-glucosidase activity related to soil carbon and N-acetylglucosaminidase and l-leucine aminopetidase activity related to soil nitrogen) were highest at the cultivation age of 30. Soil samples taken under drought conditions, displayed increased extracellular enzyme activities, soil organic carbon, soil nitrate nitrogen, and ammonia nitrogen contents while soil microbial carbon and extracellular enzyme activities declined. The soil samples taken from a cultivation age of 30 exhibited a relatively high amount of dissolved organic carbon, microbial nitrogen, nitrate nitrogen, and soil extracellular enzyme activities throughout all incubation periods. The drought conditions had a significant influence on the contents of soil nitrate nitrogen, ammonia nitrogen, total organic carbon, and microbial carbon. Furthermore, the correlation analysis of soil carbon and nitrogen related biochemical properties indicated that the carbon and nitrogen soil nutrients affected one another. The results of the study indicated that a 30-year cultivation of the tea tree had a positive effect on the accumulation of soil nutrients but tea tree cultivation for almost 50 years produced an inferior micro-ecological environment. Thus, to improve the soil environment in tea orchards, measures such as balancing fertilization and green cover, should be considered.
  • DownLoad:The response of soil nutrients (carbon and nitrogen) and extracellular enzyme activities to drought in various cultivation ages from tea orchards.PDF
  • The effects of types and doses of nitrogen addition on soil N2O flux in a cold-temperate coniferous forest, northern China
  • Authors:GENG Jing, CHENG Shulan, FANG Huajun, YU Guirui, XU Minjie, WANG Lei, LI Xiaoyu, SI Gaoyue and HE Shun
  • Abstract:Increasing atmospheric nitrogen (N) deposition would change soil N availability, and thereby changes N2O production and emission from N-limiting forest soils. However, it is still unclear about the contrasting effects of different N ion (i.e., oxidized NO3--N and reduced NH4+-N) deposition on soil N2O emission in boreal forests. In the present study, a cold-temperate coniferous forest in the Great Khingan region was selected for conducting the manipulative N addition experiment, including three forms of N fertilizers (NH4Cl, KNO3, and NH4NO3) and four rates of N addition (0, 10, 20, and 40 kg N hm-2 a-1). Soil-atmospheric N2O exchanging fluxes were measured four times per month using static chamber-gas chromatography. Simultaneously, soil temperature, moisture, and inorganic N contents were measured to explore how the main factors affect soil N2O emission. The results showed that the types and doses of N addition significantly changed soil inorganic N contents, and the accumulation of soil NH4+-N was significantly higher than that of soil NO3--N due to N addition. N addition increased N2O emission from the boreal forest soil, and the NH4NO3 addition treatments promoted high soil N2O fluxes, with an increase of 442% to 667%, which was higher than the global average (134%). There were positive correlations between soil N2O fluxes and soil temperature, and between soil N2O fluxes and soil NH4+-N contents in the litter layer. Soil N2O fluxes were driven by soil temperature, followed by soil NH4+-N contents in the litter layer. These findings suggest that atmospheric N deposition cannot lead to a significant soil NO3--N leaching and loss in boreal forests over the short term, but it can significantly promote soil N2O emission. Furthermore, exogenous NH4+ and NO3- inputs into boreal forests have synergic effects on soil N2O emission, which should be distinguished in N cycle and balance in terrestrial ecosystems using 15N tracer methods in the future.
  • DownLoad:The effects of types and doses of nitrogen addition on soil N2O flux in a cold-temperate coniferous forest, northern China.PDF
  • Effects of N addition on the plant and soil microbial community in alpine Kobresia tibetica meadow of Qinghai-Tibet Plateau
  • Authors:WANG Changting, WANG Genxu, LI Xiangzhen, WANG Yong, ZI Hongbiao and A De Luji
  • Abstract:Effects of continuous six-year N addition on the quantitative properties of plant and soil microbial communities in alpine Kobresia tibetica meadows were investigated experimentally by using field surveys and phospholipid fatty acid (PLFA) analyses. The experiment included four manipulative treatments involving both N and litter:added N (+N) with the litter removed (LR), +N with the litter left intact (LI), LI without N addition (-N), and LR with -N. Soil samples were collected at the depths of 0-10 and 10-20 cm. Aboveground biomass (AGB), litter biomass, microbial community composition, and nutrient content were measured. The results showed that (1) fertilization did not have significant effects on AGB and litter biomass. (2) N addition significantly increased the abundance of the microbial group PLFAs at the soil depth of 0-10 cm, particularly the abundance of the bacterial PLFAs (B PLFAs) and gram-positive bacterial PLFAs (G+ PLFAs), but decreased microbial abundances at the soil depth of 10-20 cm. (3) The ratio of the normal saturated fatty acids/monounsaturated fatty acids and B PLFAs/fungal PLFAs (F PLFAs) increased with the increase in the soil depth. (4) G+ PLFA and F PLFA contents were significantly and positively correlated to pH, available phosphorus, available nitrogen, and soil organic matter contents at 0-10 cm soil depth. The contents and abundance of fatty acids were mainly regulated and affected by initial nutrient level in the topsoil after short-term N addition. These results indicate that microbial communities in this alpine tundra are sensitive to both litter and N inputs, and that the vertical structures of these communities are particularly vulnerable.
  • DownLoad:Effects of N addition on the plant and soil microbial community in alpine Kobresia tibetica meadow of Qinghai-Tibet Plateau.PDF
  • Changes in the physical properties of soil in forestlands after 22 years under the influence of the Conversion of Cropland into Farmland Project in Loess region, Western Shanxi Province
  • Authors:ZHANG Xiaoxia, YANG Zongru, ZHA Tonggang, ZHANG Zhiqiang, WANG Gaomin, ZHU Yushen and LÜ Zhiyuan
  • Abstract:The physical properties of soil such as soil particle size distribution, bulk density, and porosity are interrelated and have important effects on soil fertility and hydrological processes. Such processes include surface runoff, infiltration, groundwater recharge, and water yield. Excessive soil erosion in the Loess Plateau has resulted in severe degradations of the physical properties of the soil, such as increased bulk density, reduced aggregate stability, and reduced water retention. Soil properties are likely to change when large vegetation restoration efforts, such as the Conversion of Cropland into Farmland Project (CCFC) in China, are implemented. These changes in soil properties can affect vegetation coverage, litter accumulation, root penetration, and soil biological activity. Three typical arbor forests, which were converted from farmland 22 years ago in western Shanxi Province, were selected to study the depth and extent under the influence of the CCFC on the physical properties of the soil. We examined soil density, soil total porosity, and capillary porosity using field sampling and laboratory analysis. These arbor forests included Quercus wutaishanica, a natural recovery forest (NR), Pinus tabulaeformis×Robinia pseudoacacia, an artificial mixed forest (MF), and Robinia pseudoacacia, an artificial pure forest (PF). Cultivated lands (CK) were chosen as the control. Results of the study revealed that:1) compared to the cultivated lands, there were significant changes in soil bulk density above the 80 cm soil layer of the natural recovery forest (P < 0.05). There was an average reduction in soil bulk density of 28.78% and the largest variability was found in the 10-20 cm soil layers. Compared to the control, soil density above the 60 cm layer of the artificial forests, MF and PF, was reduced by 10.58% and 8.34% respectively, and the differences in the 20-40 cm layers were the most significant, 2) the total soil porosity above the 80 cm soil layer in three kinds of farmland increased significantly compared to cultivated land (P < 0.05). The ranking of total soil porosity from highest to lowest was:NR (35.53%) > MF (15.04%) > NR (13.68%), and the largest variability was found in the 20-40 cm layers, 3) the soil capillary porosity of NR, MF, and PF were respectively 1.36, 1.13, and 1.12 times those found in the cultivated land. The most obvious change of the natural recovery forest and artificial forest were found above the 80 cm and 60 cm layers respectively. The most drastic change was found in the 40-60 cm layers in both forests, and 4) the organic soil matter and clay content had significant effects on the physical and chemical properties of the soil. The increase of organic soil matter was as high as 31%, and interpretation of the clay content was between 44% and 51% of the change in soil bulk density, total porosity, and capillary porosity (P < 0.01). The results of this study suggest that the influence natural recovery forests have upon the physical properties of soil is greater than that of the artificial forests. This is mainly due to thicker litter and humus, superior biological diversity, more frequent microbial activity, and further developed tree roots in the natural recovery forests.
  • DownLoad:Changes in the physical properties of soil in forestlands after 22 years under the influence of the Conversion of Cropland into Farmland Project in Loess region, Western Shanxi Province.PDF
  • Effect of Soil Ameliorants on the Biochemical Properties of Coastal Saline-alkali Soil in the Yellow River Delta
  • Authors:WANG Ruitong, SUN Jingkuan and LU Zhaohua
  • Abstract:The present study analyzed the improved biochemical properties of the coastal saline-alkali soil in the Yellow River Delta using four factors of a four level orthogonal variance analysis. Four kinds of ameliorants, including cow dung (A), gypsum (B), straw (C), and a water-retaining agent (D), were applied with different formulas. The objective of the present study was to determine the most efficient drainage scheme and provide a theoretical basis for the improvement of the coastal saline-alkali soil in the Yellow River Delta. The results indicated that the effect of cow dung, gypsum, and straw on soil respiration intensity, phosphatase, urease, dehydrogenase, and microbial biomass carbon and nitrogen showed significant(P < 0.05)differences among the treatments with improvement; and the effect of the water-retaining agent on microbial biomass C and N showed significant (P < 0.05)differences among the treatments with improvement. Significantly higher indicator values than the control group were also observed. The contribution of the four kinds of ameliorants differed in the improvement of saline soil conditions. Considering the results, the most efficient formula for soil respiration intensity, enzymes, and microbial biomass C and N was A4B3C2D2. Compared to the control group, soil respiration intensity, phosphatase, urease, dehydrogenase, and microbial C and N increased by 109.64%, 89.54%, 62.20%, 81.75%, 60.50%, and 118.00%, respectively. The correlation analysis indicated that there were significant (P < 0.05)correlations between the soil biochemical parameters, except for microbial N and urease. The results of the current study could provide a theoretical basis for the improvement and utilization of saline alkali soil in the Yellow River Delta.
  • DownLoad:Effect of Soil Ameliorants on the Biochemical Properties of Coastal Saline-alkali Soil in the Yellow River Delta.PDF
  • Effects of soil water gradient on photosynthetic characteristics and stress resistance of Populus pruinosa in the Tarim Basin, China
  • Authors:WANG Haizhen, HAN Lu, XU Yali, NIU Jianlong and YU Jun
  • Abstract:Water deficit is a major limiting factor in vegetation recovery and reconstruction in the Tarim Basin in the extremely arid desert region of northwest China. Populus pruinosa Schrenk is an ecologically important species growing in this region. However, the P. pruinosa population has been declining in recent years because of the low underground water table, mainly caused by increased human water consumption. Currently, the mechanisms underlying the decline in photosynthesis of P. pruinosa under soil water declines are not clear. The objective of our study was to investigate the effects of the soil water gradient on photosynthesis, and the relationship between photosynthesis and soil water content. Our study will enhance our understanding of the photo-physiological characteristics of P. pruinosa exposed to soil water declines and provide valuable information for the protection of this vulnerable species. Saplings of P. pruinosa were planted in pots under four different soil water gradients. The effects of the soil water declines on the photosynthetic characteristics and stress resistance of P. pruinosa were evaluated by analyzing gas exchange, photosynthetic light and CO2 response curves, pigments, stem water potential, and osmotic adjustment substances. The results showed that:(1) The net photosynthetic rate(Pn), transpiration rate, stomatal conductance, intercellular CO2 concentration, and light use efficiency of P. pruinosa decreased with a gradual decrease in soil water content by 35.53%, 25.32%, 48.18%, 15.62%, and 40.92%, respectively, under severe soil drought in comparison to normal soil water content(CK). However, the phenomenon of "noon break" was apparent, and non-stomatal limitation was responsible for a reduction in Pn. Water use efficiency(WUE) could be improved by 3.05% under mild drought conditions relative to the CK, and Pn was maintained at a high level. (2) Light ecological amplitude decreased, CO2 compensation point increased, ribulose 1,5-diphosphate (RuBP) regeneration was limited, and light/CO2utilization efficiency, rubisco activity, and photosynthetic efficiency of P. pruinosa decreased with a decrease in soil water content. Compared to the CK, light response parameters(maximum net photosynthetic rate[Pnmax], apparent quantum efficiency[AQY], light saturation point[LSP], carboxylation efficiency[CE], Photosynthetic capacity[Amax], photorespiratory rate[Rp], maximum carboxylation rate[Vcmax], maximum electron transport rate[Jmax], and triose-phosphate utilization rate[TPU]) significantly decreased(P < 0.05). Notably, Pnmax, Amax, and biochemical parameters of photosynthesis decreased by 42.65%, 38.26%, and 57.10% (moderate drought) and 63.01%, 65.88%, and 73.43% (severe drought), respectively. (3) Stem water potential and pigment content were significantly reduced(P < 0.01), the pigment composition proportion of the light reaction center was altered, and membrane lipid peroxidation(MDA) was significantly enhanced(P < 0.01) with decreasing soil water content. P. pruinosa mainly accumulated proline and soluble protein to eliminate reactive oxygen and alleviate the impairment of the photosynthetic apparatus under soil drought. Irreversible damage was caused to the photosynthetic system of P. pruinosa, and normal photosynthesis was seriously inhibited under severe drought. Therefore, declines in soil water content resulted in drought stress and reduced photosynthetic ability. This indicated that the decline in the P. pruinosa population might be caused by the lower soil moisture. In conclusion, the soil water content for maintaining higher Pn and WUE in P. pruinosa forestlands should be approximately 60%-65% of the field capacity in the Tarim arid-desert region to adhere to the management principles of efficient water conservation and vegetation restoration in extremely arid areas.
  • DownLoad:Effects of soil water gradient on photosynthetic characteristics and stress resistance of Populus pruinosa in the Tarim Basin, China.PDF
  • N and P stoichiometric characteristics of leaves, litter, and soil for three dominant tree species in the Shaanxi Province
  • Authors:JIANG Peipei, CAO Yang, CHEN Yunming and ZHAO Yiping
  • Abstract:Plant nutrient stoichiometry can be used to distinguish the biological entities based on element composition and responses to environmental factors. We determined the N and P stoichiometry for leaves, litter, and soil associated with 3 dominant tree species:Robinia pseucdoacacia, Quercus liaotungensis, and Pinus tabulaeformis, at 39 sites in 29 county-level cites of the Shaanxi Province. We aimed to distinguish the differences in leaf, litter, and soil N and P stoichiometry among the different tree species, and their relationships with environmental factors in the Shaanxi Province. Leaf N and P concentrations and their ratios, were Robinia pseucdoacacia > Quercus liaotungensis > Pinus tabulaeformis. Compared with plant leaves, the range and quantity of litter N and P concentration significantly reduced (P < 0.05), and the order was still Robinia pseucdoacacia > Quercus liaotungensis > Pinus tabulaeformis, while the order for the N:P ratio was Pinus tabulaeformis > Quercus liaotungensis > Robinia pseucdoacacia. There were no significant correlations (P < 0.05) between Robinia pseucdoacacia, Quercus liaotungensis, and Pinus tabulaeformis leaf N (or P) and soil N (or P), indicating that their growth was not limited by N or P. In total, there were significant correlations between leaf P and soil P (P < 0.05), which indicated that the growth of the plant was limited by P in the Shaanxi Province. Leaf N and P increased with mean annual temperature and precipitation, especially for Robinia pseucdoacacia. The leaf N:P ratio for the 3 tree species did not clearly correlate with the environmental factors. Litter N increased with mean annual temperature and precipitation, and decreased depending on the latitude and longitude. Although litter P showed no significant relationships with temperature and latitude (P < 0.05), it declined with precipitation and longitude. Litter N:P ratio increased with temperature and precipitation and decreased with latitude. Soil N and P increased with latitude and altitude, and decreased with mean annual temperature, mean annual precipitation, and longitude. The soil N:P ratios demonstrated an opposite trend. Soil P was more closely correlated with environmental factors than N, and the relationship between the 0-10 cm and 10-20 cm N and P stoichiometry in terms of environmental factors was almost the same.
  • DownLoad:N and P stoichiometric characteristics of leaves, litter, and soil for three dominant tree species in the Shaanxi Province.PDF
  • Effects of simulated nitrogen deposition and precipitation changes on litter decomposition in an evergreen broad-leaved forest in the rainy area of western China
  • Authors:XIANG Yuanbin, ZHOU Shixing, XIAO Yongxiang, HU Tingxing, TU Lihua, HUANG Congde and GAO Baodan
  • Abstract:Nitrogen deposition and changes in precipitation patterns are two primary effects of global climate change. In order to understand the effects of both nitrogen deposition and precipitation changes, and their interaction on litter decomposition, in an evergreen broad-leaved forest, from November 2013 to May 2015, an experiment was conducted in situ in the rainy area of western China. The study included six treatments:control (CK), nitrogen deposition (N), water reduction (R), water addition (A), nitrogen deposition×water reduction (NR), and nitrogen deposition×water addition (NA). The results revealed that the leaf decomposition rate was higher than the twig decomposition rate, and litter decomposition was faster in summer than in other seasons. After decomposition for 18 months, the leaf and twig residual rates were 45.86% and 86.67%, respectively. It took 1.42 years for 50% of the leaf litter mass to decompose, which was 6.19 years shorter than that for twigs. The decomposition coefficient of each treatment was as follows:k(A) > k(CK) > k(NA) > k(N) > k(R) > k(NR), and the residual rate of twig decomposition was N > NR > R > NA > CK > A. The simulated nitrogen deposition, water reduction, and water addition treatments, which were performed to decompose 50% of the leaf litter mass, took 1.79, 1.94, and 1.36 a, respectively; and 8.84, 8.63, and 6.47 a, respectively, to decompose 50% of the litter mass. Each treatment performed to decompose 95% of the leaf litter required 5.37-11.33 a, while decomposition of 95% of the twig litter required 27.41-33.84 a. Under the same nitrogen deposition conditions, water addition treatment promoted the decomposition of leaf litter, while water reduction treatment reduced the decomposition of leaf litter. Under the same precipitation conditions, nitrogen deposition reduced the decomposition of leaf litter. Thus, nitrogen deposition and precipitation changes had a significant effect on litter decomposition, and their interaction effect was not significant (P > 0.05). Considering that nitrogen deposition increases continuously and that global climate change is occurring, water addition treatment promoted the decomposition of litter, and nitrogen deposition and water reduction treatment reduced the decomposition of litter in an evergreen broad-leaved forest in the rainy area of western China. Therefore, the interaction between nitrogen deposition and precipitation changes did not have a significant effect on litter decomposition in this forest ecosystem.
  • DownLoad:Effects of simulated nitrogen deposition and precipitation changes on litter decomposition in an evergreen broad-leaved forest in the rainy area of western China.PDF
  • Impacts of climate change on the potential geographical distribution of broadleaved Korean pine (Pinus koraiensis) forests
  • Authors:JIA Xiang, MA Fangfang, ZHOU Wangming, ZHOU Li, YU Dapao, QIN Jing and DAI Limin
  • Abstract:Species-environment relationships have always been a central issue in ecology and biogeography. The adaptation of species to a changing natural environment, including topographical and climatic factors, determines its geographic distribution. Accumulating evidence has revealed that Northeast China has experienced the greatest temperature increase since the 1950s, which in turn affected species distribution in this region. Broadleaved Korea pine (Pinus koraiensis) mixed forest (BKF) is the native forest type in the southern part of Northeast China. The distribution area of this species has shrunk substantially due to historical overexploitation. It is important for forest managers to be able to predict the potential geographic distribution of BKF based on species-environment relationships. Although the distributions of individual species in BKF such as P. koraiensis and Quercus mongolica have been reported previously, few studies have focused on the potential geographic distribution of BKF. In this study, four dominant tree species -P. koraiensis, Q. mongolica, Tilia amurensis and Fraxinus mandshurica, which together account for more than 80% of the growing stock in primary BKF, were selected to represent this forest type. Nineteen climatic and three topographic variables in Northeast China that are considered to be most likely influences on the geographic distribution of tree species were selected as environmental factors. To identify the major climatic and topographic factors controlling BKF distribution and simulate the potential geographic distribution of BKF under current climatic condition, the geographic distribution records of the dominant tree species, together with the environmental factors, were used in the Maxent model. The future geographic distributions of BKF were consequently predicted for the 2020s, 2050s, and 2080s, based on three kinds of climate change scenarios (SRES-A2, SRES-A1B, SRES-B1) published by the Intergovernmental Panel on Climate Change (IPCC). For the four dominant tree species, the simulations showed that the area under the curve indexes (AUC) were 0.925, 0.890, 0.859, and 0.847, respectively. All these values exceeded 0.8, which indicates that the models had a good predictive performance. The major environmental factors affecting the distribution of BKF included annual precipitation, precipitation seasonality, elevation, annual mean temperature and mean temperature of wettest quarter. For the entire region, 11.69% of the total area was identified to be of high suitability for BKF distribution, 23% was of low suitability, and 65.31% of the area was unsuitable. Under the A2, A1B, and B1 scenarios, the model predicted that both the southern and northern boundary of the high suitability area for BKF will shift northward. Overall, the high suitability area in this region was predicted to decrease, with the extent of the decrease depending on the severity of climate change. For example, under the A2 and A1B scenarios, the high suitability area in Northeast China will be less than 1% of the region by the 2080s. Overall, the results indicate that if no effective measures are taken to mitigate climate change, there is a great possibility that BKF will disappear from Northeast China.
  • DownLoad:Impacts of climate change on the potential geographical distribution of broadleaved Korean pine (Pinus koraiensis) forests.PDF
  • Differences in fragmentation processes between western natural forests and southeastern forest plantations in the United States: a case study comparing the states Washington and Mississippi State
  • Authors:REN Xinyu, LÜ Yingying, WU Yingwei, LI Mingshi and LI Weizheng
  • Abstract:Forest loss and fragmentation have long been one of the most vital concerns of the international community. Landscape fragmentation includes five different spatially explicit processes:perforation, dissection, subdivision, shrinkage, and attrition. Following this theory, a forest fragmentation process model that can detect these spatially explicit processes, as well as the ecological consequences of forest landscape fragmentation, was developed using ArcGIS Modeler. Using the National Land Cover Database (years 2001, 2006, and 2011), the forest fragmentation process model was applied to Washington and Mississippi in the USA. Deforested patches were quantified and categorized into one of four fragmentation processes, by merging the dissection spatial process into the subdivision spatial process (because of its principal linear feature). Furthermore, the spatio-temporal differences in fragmentation pattern between natural forests and plantations were compared. For natural forests, forest fragmentation mainly occurred in the urban/forest, cultivated/forest, and shrubland/forest interfaces, whereas the pattern of deforested plantation patches dispersed sparsely and irregularly throughout the region. The subdivision and shrinkage patches in natural forests usually followed the perforation, subdivision, and shrinkage patches of the previous period. In contrast, for the plantations, the spatial transition relationships of the four fragmentation processes were not as apparent as for the natural forests. Nonetheless, for both natural forests and plantations, the overall temporal fragmentation pattern tended to have a similar "shrinkage-attrition-perforation/subdivision" tendency. This tendency was characterized by an early shrinkage dominance, followed by its gradual disappearance. Furthermore, perforation and subdivision components increased gradually, and a new dominance was established accordingly.
  • DownLoad:Differences in fragmentation processes between western natural forests and southeastern forest plantations in the United States: a case study comparing the states Washington and Mississippi State.PDF
  • Effects of simulated nitrogen deposition on greenhouse gas emissions from alpine meadows in northern Tibet
  • Authors:LIANG Yan, HASBAGAN Ganjurjav, CAO Xujuan, ZHANG Weina, ZHANG Yong, LI Wenhan, GAO Qingzhu, WAN Yunfan, LI Yu'e, DANJIU Luobu and He Shicheng
  • Abstract:The alpine meadow is the largest and most important ecosystem in northern Tibet. Recently, nitrogen deposition in Tibet has had a profound impact on carbon and nitrogen cycles in grassland ecosystems. To assess the impact of nitrogen deposition on greenhouse gas emissions from alpine meadows in northern Tibet, we conducted a nitrogen fertilizing experiment, using four fertilizing levels of 0, 7, 20, and 40 kg hm-2 a-1, in Nagqu County in the growing season in 2014. Our results showed that the impact on greenhouse gas emission varied with different levels of nitrogen deposition. Regarding daily variation, nitrogen significantly enhanced CO2 emission but had no effect on the absorption of CH4, or the emission of N2O. Overall, nitrogen deposition significantly increased greenhouse gas emissions. The highest emission occurred with the N20 treatment, and there was a positive correlation among CO2, net primary productivity (NPP), and total organic carbon (TOC) (P < 0.05). The total nitrogen (TN), NH4+-N, and NO3--N were not correlated with CO2 (P > 0.05), and the same pattern was observed in the relationship between CH4 and TN/NPP/TOC/NH4+-N/NO3-N (P > 0.05). N2O levels showed a significant linear correlation with NPP/TOC/NO3-N (P < 0.05), but were not correlated with TN/NH4+-N (P > 0.05). With additional nitrogen deposition expected in the future, greenhouse gas emissions would increase significantly and have a positive or negative feedback on climate change in Northern Tibet.
  • DownLoad:Effects of simulated nitrogen deposition on greenhouse gas emissions from alpine meadows in northern Tibet.PDF
  • Autotoxins exuded from roots and the effects of PAEs on antioxidant capacity in roots of tobacco seedlings
  • Authors:DENG Jiajun, ZHANG Shixiang, ZHANG Fusheng, ZHANG Yanling, HU Feng and LI Huixin
  • Abstract:Root exudates of two varieties (Burley and K326) of tobacco seedlings cultured in a hydroponic medium were collected, and identified using gas chromatography-mass spectrometry (GC-MS). Further, the effects of different concentrations of dibutyl phthalate (DBP) and diisooctyl phthalate (DIOP) on root antioxidant capacity were assessed using pot culture experiments. The results revealed three main compounds in Burley root exudates. The relative content of autotoxin phthalate esters (PAEs) at the two-, four-, and six-leaf stages were 7.6%, 0.3%, and not detected, respectively. However, there were nine main compounds in K326 root exudates. The relative PAE content at the two-, four-, and six-leaf stages were 35.6%, 51.3%, and 2.2%, respectively. PAEs such as DIOP and DBP were identified as the major autotoxins in root exudates of both tobacco seedlings. The rate of superoxide anion radical generation in roots significantly increased at concentrations greater than 0.1 mmol/L DIOP and DBP (P < 0.05). Both superoxide dismutase and catalase activities increased with increasing DIOP concentrations, with a peak at 0.5 mmol/L, and subsequently decreased at higher concentrations. Accumulated malondialdehyde concentrations increased with increasing DIOP and DBP concentrations, and the magnitude of malondialdehyde content was DIOP > DBP, which indicated the order of their toxic effect. Finally, our findings also revealed that when PAEs reached 0.5 mmol/L, they decreased the antioxidant capacity of the root system, initiated oxidative damage of the root cell membrane system, and caused a further decrease in root absorption and mineral metabolism, and thereby led to autotoxicity in the tobacco plants.
  • DownLoad:Autotoxins exuded from roots and the effects of PAEs on antioxidant capacity in roots of tobacco seedlings.PDF
  • Estimating the Spartina alterniflora fractional vegetation cover using high spatial resolution remote sensing in a coastal wetland
  • Authors:ZHOU Zaiming, YANG Yanming and CHEN Benqing
  • Abstract:Spartina alterniflora is an important invasive species in coastal beach ecosystems, and its distribution and cover are basic parameters that affect the ecology of these wetlands. In this study, S. alterniflora distribution and fractional vegetation cover were investigated, using high spatial resolution satellite remote sensing images from SPOT6 (6 m), and low altitude Unmanned Aerial Vehicle (UAV) images (10 cm) from Sansha Bay (San Du Ao). The latter is a typical coastal wetland area in Ningde, Fujian Province, China. For the extraction of SPOT6 remote sensing information, support vector machine and maximum likelihood classification methods were explored. In addition, a geographic information system (GIS) technique was used to reduce errors. As a result, an accurate S. alterniflora distribution map was obtained. Furthermore, the normalized difference vegetation index (NDVI) of image pixels was calculated for the S. alterniflora distribution area. Subsequently, with the NDVI of pure S. alterniflora pixels and pure beach soil pixels, the fractional vegetation cover could be calculated. S. alterniflora area was 20.19 km2 in the total study region. S. alterniflora area in the Jiaocheng district was 9.63 km2 and was distributed mainly in Zhangwan and Southern Jiaocheng, accounting for 47.70% of the total study area. S. alterniflora area in Fuan County was 5.20 km2, was distributed mainly in Yantian Bay and Magang Bay, and accounted for 25.76%. The fractional vegetation cover of S. alterniflora was mostly a medium (40%-60%) and a high degree (60%-80%) cover. In contrast, much less of the S. alterniflora cover displayed a low degree, (<40%) or much higher degree (>80%), of fractional cover. Statistical tests indicated that the fractional vegetation cover area of 40%-60% and 60%-80% represented 5.44 km2 and 4.95 km2, respectively, and accounted for 26.92% and 24.52% of the total area, respectively. Overall, the fractional vegetation cover area of a medium and high degree was 10.39 km2, and accounted for 51.44% of the whole S. alterniflora area. Based on these results, it is necessary to increase the monitoring and additional studies on S. alterniflora in Sansha Bay. In addition, relevant measures should be taken to reduce biological invasion damage, and to preserve the efficiency of this coastal wetland's ecological functioning. To evaluate the estimation accuracy of the S. alterniflora vegetation cover, 26 sample sites were selected randomly according to the overlapping SPOT 6 and UAV image region. An accuracy analysis indicated a root mean square error (RMSE) of 0.117, and a determination coefficient R2 of 0.918. Therefore, our S. alterniflora fractional vegetation cover results, as estimated by SPOT6 high spatial resolution remote sensing, had a satisfactory precision. These results could therefore be used as a reference for ecological coastal wetland research.
  • DownLoad:Estimating the Spartina alterniflora fractional vegetation cover using high spatial resolution remote sensing in a coastal wetland.PDF
  • Effects of forest gap size on leaf litter weight loss and nutrient release of four species in Pinus massoniana plantations
  • Authors:LIU Hua, ZHANG Danju, ZHANG Jian, YANG Wanqin, LI Xun, ZHANG Yan and ZHANG Mingjin
  • Abstract:Litter decomposition is an essential component of the nutrient balance and material cycling in Pinus massoniana plantations. Forest gap size could play an important role in litter decomposition due to its effects on the microenvironment. To evaluate the effects of forest gap size on leaf litter mass loss and nutrient release of four native species (Toona ciliata, Phoebe zhennan, Cinnamomum camphora, Pinus massoniana), a field experiment consisting of seven gap sizes (i.e., G1:100 m2, G2:225 m2, G3:400 m2, G4:625 m2, G5:900 m2, G6:1225m2, and G7:1600 m2) was established in 2013. The results showed that:1) Forest gap size significantly affected leaf litter mass loss of C. camphora, but not the mass loss of the other three species. The litter nutrient release rate at the gap center for T. ciliata (N, P), P. zhennan (N, P), C. camphora (N, P, K) and P. massoniana (P, K) were significantly influenced by forest gap size. Furthermore, leaf litter mass loss rate, and N and P release rates were significantly higher in small and medium sized gaps (G1-G4) than in large gaps (G5-G7) (P < 0.05). However, litter K release rates were significantly lower in small and medium sized gaps (G1-G4) than in the larger gaps (P < 0.05). 2) The leaf litter collection location in the forest gaps influenced the litter K release rate of T. ciliata, P. zhennan, and P. massoniana. The K release rate of T. ciliata and P. zhennan litter at the gap centers were significantly higher than those at the gap edges (P < 0.05). In contrast, P release rates of C. camphora litter and K release rates of P. massoniana litter at the gap center were significantly lower than rates at the gap edges (P < 0.05). 3) Litter mass loss and nutrient release rates of T. ciliata were the highest among the four species. According to the fitting equation, the 50% and 95% decomposition times for T. ciliata were 5.29 and 23.14 months, respectively. Overall, forest gap size and litter sampling location in the gaps significantly affected litter mass loss and nutrient release. However, the extent of these effects and dynamic changes depended on the initial litter quality. These results can be beneficial for the scientific management of P. Massoniana plantations in low mountainous and hilly areas of subtropical zones.
  • DownLoad:Effects of forest gap size on leaf litter weight loss and nutrient release of four species in Pinus massoniana plantations.PDF
  • Factors affecting species richness and beta diversity of vascular plants on small islands in the Wenzhou region of eastern China
  • Authors:WANG Jinwang, WEI Xin, CHEN Qiuxia, LI Xiaowen and YANG Sheng
  • Abstract:We conducted field surveys on 20 small, uninhabited islands off the coast of Wenzhou in the Pacific Ocean and recorded 366 vascular plants belonging to 244 genera and 96 families. Of these, 140 were woody and 226 were herbaceous species. Five regression models were constructed to predict species richness (S) and β diversity and the final models were selected based on the Akaike information criterion (AIC). The effects of island size (A), distance to the mainland (Im), inter-island distance (Ii), shoreline length (Per), perimeter to area ratio (PAR), elevation (E), habitat types (Hn), habitat diversity (Hd), and island shape index (SI) were examined. Model SAHnR had the highest Akaike weight, 40.26%, with a ratio of 1.19, 2.17, 5.80, and 94.08 over SAR, SAHdR, BR-SAR1, and BR-SAR2, respectively. Species richness increased with island size following the classic species-area relationship. However, the species similarity index decreased with increasing Ii. The importance of all exploratory variables on β diversity was Im =0.61, Ii =0.56, PAR=0.49, A= 0.20, Per =0.14, Hn =0.072, E =0.065, and SI=0.05, suggesting that isolation (i.e., Im and Ii) played a major role in β diversity. Plant species richness was also significantly affected by PAR and Hd. Stepwise regression showed that the best models to predict S were:S =76.714+1.696A-0.046PAR (R2=0.839), S_woody=6.525+0.455A+24.544Hd (R2=0.697), and S_herb aceous=66.899+1.285A-0.04PAR-23.434Hd (R2=0.865) for total, woody, and herbaceous species richness, respectively. This further indicated that species richness of different growth forms (i.e., woody and herbaceous) on these islands was not solely dependent on island size.
  • DownLoad:Factors affecting species richness and beta diversity of vascular plants on small islands in the Wenzhou region of eastern China.PDF
  • Canopy seed bank and serotinous cones of Pinus yunnanensis forests
  • Authors:SU Wenhua, CUI Fengtao, ZHAO Yuanjiao, ZHOU Rui, ZHANG Guangfei and CAO Jianxin
  • Abstract:Canopy seed banks and serotinous adaptations are particularly prominent in fire-prone ecosystems. In this study, we recorded the number of open and closed cones in a P. yunnanensis forest, we observed the ripening year of the cones, and investigated the response of closed cones to high temperatures and forest fires. Closed cones could be retained in the canopy for seven years, and open cones nine years. The germination rate of closed cone seeds decreased with increased serotiny time. The germination rate of seeds from cones retained in the canopy for nine years was 2.9%. There were about 100,000 viable seeds in the canopy seed bank per 100-m2 plot, which was two times higher than the annual seed production. From every cohort, some of the cones would release seeds, and all seeds were released within eight years after maturation. The serotinous cones of P. yunnanensis could be induced to open with high temperatures (over 40℃). With increasing temperatures, the time to open the cones decreased. The number of released seeds in post-fire plots was 2.6-fold higher than in unburned plots. In addition, the rate of germination was (69.8±22.8)% for released seeds in post-fire plots. These results suggest that P. yunnanensis is a weakly serotinous species. Fire significantly increased the release of seeds form the canopy seed bank, whereas the serotiny time was similar to seed longevity in closed cones. Furthermore, released seeds in the post-fire and unburned plots originated from cones that ripened in different years. In sum, the serotinous cones for P. yunnanensis were adapted to fire in fire-prone habitats.
  • DownLoad:Canopy seed bank and serotinous cones of Pinus yunnanensis forests.PDF
  • Responses and adaptive status of three garden plants exposed to night illumination
  • Authors:CHEN Lianghua, CAO Yi, YANG Wanqin, ZHANG Jian and HE Shuhui
  • Abstract:Light pollution is one of the most serious pollutants in urban ecosystems. Existing research in this field has mainly focused on the effects of light pollution on human health, life cycles, and behavior and actions of insects or other animals, whereas information regarding its effects on the physiology and ecology of plants is lacking. We used Impatiens balsamina, Gardenia jasminoides, and Dendranthema morifolium to document biomass accumulation and allocation, blossoming, pigmentation, C and N content (and C/N ratio), and activities of antioxidant enzymes in response to night illumination produced by a white LED from 18:00 to 24:00 (T1 treatment), from 18:00 to 08:00 the following day (T2 treatment), and natural photoperiod (control; CK). The main results were as follows:(1) Compared to CK, T1 and T2 increased the biomass of I. balsamina by 1.4 and 1.9 times, respectively, and the C/N ratio in leaves by 1.2 and 1.9 times, respectively, but decreased the N content in leaves and stems, and content of pigments in leaves. The T1 treatment delayed florescence, and the T2 treatment inhibited flowering. (2) Although neither T1 nor T2 affected the florescence of G. jasminoides, night illumination increased the average number of flowers and decreased average weight per flower. Compared to CK, T2 significantly increased the C/N ratio in flowers and content of malondialdehyde (MDA), although it decreased chlorophyll a, b, and total chlorophyll content in leaves. (3) Biomass and physiological traits were not obviously affected in D. morifolium. However, both T1 and T2 inhibited flowering. These results indicated that flowering of both I. balsamina and D. morifolium were sensitive to the altered photoperiodism induced by nighttime illumination. In addition, growth and nutrient status of I. balsamina was negatively affected by nighttime illumination, and there was a detrimental effect on the leaves of G. jasminoides. Generally, when compared to T2, the T1 treatment exerted fewer negative impacts on the three species. Therefore, in urban light management, we should shorten the duration of illumination to the degree it is practical. This will not only save electric energy, but also lessen the negative influence on the physiology and ecology of garden plants.
  • DownLoad:Responses and adaptive status of three garden plants exposed to night illumination.PDF
  • Carbon balance analysis methods of grassland agro-ecosystems
  • Authors:LOU Shanning, CHEN Xianjiang and HOU Fujiang
  • Abstract:According to the structures of grassland agro-ecosystems, their carbon balance represent the sum of the carbon balances of the four production levels, or the sum from its three interfaces. The carbon balance per production level or interface is the sum of the carbon that is taken up and lost through the different processes in that level or interface. The carbon balance analysis method based on four production levels can quantify which of the processes in the production are either a carbon sink or source. For example, carbon and nitrogen accumulation such as Carbon and Nitrogen sink, soil and water conservation are carbon sink process in Pre-plant production level. The grassland tourism hunting and so on, are the process of carbon source in Pre-plant production level. Photosynthesis and carbon and nitrogen assimilation of biological nitrogen fixation are the process of carbon sink in Plant production level. Greenhouse gases emission is the process of carbon source in Plant production level. The process of carbon sink and source in Animal production level are mostly Carbon fixation in animal product and greenhouse gases emission of ruminant. Carbon fixation in forage and animal products are the process of carbon sink in Post-biological production level. Processing and transport activities are the process of carbon source in Post-biological production level. This can subsequently facilitate improvements in the management of carbon sequestration in grassland production. Furthermore, the carbon balance analysis method based on three interfaces can determine the production mechanisms of carbon sinks and sources, as well as their spatial and quantitative relationships. This can contribute to regulating and controlling the carbon emissions from grassland agro-ecosystems. However, both methods cannot accurately quantify a grassland system's paths of carbon uptake and output, or its utilization efficiency. The carbon balance analysis by the balance between carbon input and output can quantify the pathway of carbon movement. This method is simple and more succinct; however, it is not applicable to farmland scale management of carbon sequestration. Considering a ranch in the Qilian Mountains, China, and a dairy farm in Tasmania, Australia, as examples, three methods were used for analyzing their carbon balances. The results showed that carbon emissions from tourism, product processing, and marketing accounted for the major portions of the total emissions from the grazing management system. Their main carbon sinks were carbon stored in the forage and the soil. Overall, optimal grassland management would benefit from adding carbon sinks and reducing carbon emissions.
  • DownLoad:Carbon balance analysis methods of grassland agro-ecosystems.PDF
  • Changes in the spatial structure of ecological land and ecosystem service values in nine key districts of Chongqing City over the past 25 years
  • Authors:ZHANG Qian, GAO Ming, YANG Le, CHEN Chenglong, SUN Yu and WANG Jinzhu
  • Abstract:Land-use change is a major factor that drives changes in ecosystem services. Measuring variations in the values of ecosystem services that correspond to changes in land use is an effective way of assessing environmental costs and benefits for environmental policy planning. The present study adopted the above approach in the current context of rapid urbanization, using the nine key districts of Chongqing City (a typical fast-growing Chinese city) as a case study. Conducting accurate assessments of the structure of ecological land and associated ecosystem service values has emerged as the most effective approach for understanding the causes and patterns of the functional degradation of ecological services. Together with accurate spatial datasets of LandsatTM images from 1988 to 2013, we used remote sensing, geographic information system (GIS) technologies, and ecosystem service value assessment methods to analyze the urbanization levels of Chongqing`s nine key districts. The present study explored variations in the spatial structure of urban ecological land and the effects of different levels of urbanization across these districts on the expansion of urban construction land. The study further assessed changes in monetized values of ecosystem services that were caused by changes in the structure of urban ecological land. The results showed that from 1988 to 2013, urbanization levels of the study districts first underwent an acceleration phase, subsequently shifting to a deceleration phase, and finally reaching a saturation phase. Increased urbanization levels had a significant impact on the expansion of urban construction land. The ecological land in these districts of Chongqing provides a number of ecosystem services, including food production, supplemental raw materials, waste treatment, soil formation and protection, climate regulation, gas regulation, and biodiversity and water conservation. The structural changes of ecological land evidenced a "two minus three growth" pattern. The value of ecosystem services calculated for the study districts revealed a total loss of 260.60×106 Yuan over the past 25 years. The greatest loss was incurred for the value of farmland ecosystem services that showed a reduction of 24.5%. Together with the spatial distribution change, entailing the expansion of urban construction land toward the west, north, and south, the greatest loss in terms of the ecosystem service value was incurred in the region between the Zhongliang and Tongluo mountains. The main reason for the decline in ecosystem service values over the entire study area was the negative impact resulting from farmland reduction and the expansion of construction land. The present study revealed a strong correlation between the spatial pattern of ecological land and changes in ecosystem service values in relation to the different urbanization levels of Chongqing's nine key districts. Once the urbanization level reach saturation, strict regulations should be implemented to control the expansion of construction land and promote its intensive use. Efforts to protect farmlands, forests, grasslands, and wetlands should be enhanced to maintain the ecological balance of the entire region. This research can provide information and guidelines to facilitate decision-making in relation to the design of scientific and rational layouts as well as urban ecological land protection.
  • DownLoad:Changes in the spatial structure of ecological land and ecosystem service values in nine key districts of Chongqing City over the past 25 years.PDF
  • Temporal analysis of climate change and its relationship with vegetation cover on the north china plain from 1981 to 2013
  • Authors:A Duo, ZHAO Wenji, GONG Zhaoning, ZHANG Min and FAN Yunbao
  • Abstract:Global climate change has resulted in significant vegetation changes in the past fifty years. The North China Plain, the most important grain production base of China, is experiencing prominent warming and drying. Vegetation cover, which is used to monitor vegetation change, is affected by climate change, predominantly temperature and precipitation. In the present study, GIMMS (Glaobal Inventory Modelling and Mapping Studies)NDVI (Normalized Difference Vegetation Index), MODIS (Moderate-resolution Imaging Spectrometer) NDVI, and climate data, during 1981-2013, were used to investigate the spatial distribution and changes of vegetation. The relationship between climate and vegetation on the North China Plain were also analyzed on different spatial (agricultural, forest, and grassland) and temporal (yearly, decadal, and monthly) scales. (1) It was found that the temperature increased slightly (0.20℃/10a, P < 0.01). This may be due to the disappearance of the 0℃ isotherm, the rise of spring temperatures, and the increase of the isotherm (>15℃) area. At the same time, precipitation decreased significantly (-1.75mm/10a, P > 0.05). The expanding of the 400-600 mm precipitation contour area, the narrowing of ranges of 600-800 and 800-1000 mm, and excessive reduction of autumn precipitation indicated less precipitation. The sensitive areas of characteristic climatic change were mainly located between the latitudes 35-39°. The climate mutation occurred during 1991-1994. (2) Vegetation cover increased slightly in 55% of the total study area, with a rate of change of 0.00039/10a. Human activities could accelerate the changes of the vegetation cover and affect the rate of these changes. (3) Overall, the correlation between the vegetation cover and climatic factors is higher for a monthly than yearly scale. The correlation analysis between vegetation cover and climate change showed that annual vegetation cover was positively correlated with precipitation in grassland biomes; but it showed a more positive correlation with temperature in the agricultural and forest biomes. In addition, vegetation cover was temporally sensitive to precipitation. (4) The vegetation cover increased before and after the climate variations, but the rate of increase slowed down. Moreover, the grassland biome had an obvious response to the climatic variations, but the agricultural biome showed a significant response. The effect of human activity in regions of degradation was higher than that in environmentally improved areas. However, after the climate abruptly changing, the effect of human activity in environmentally improvement areas was higher than that in the degraded regions, and the influence of human activity will continue in the future.
  • DownLoad:Temporal analysis of climate change and its relationship with vegetation cover on the north china plain from 1981 to 2013.PDF
  • Farmers' perception of climate change in high-frigid ecological vulnerable region: a case of Gannan Plateau
  • Authors:LUO Li, ZHAO Xueyan, WANG Yaru, ZHANG Qin and Xue Bing
  • Abstract:Global climate change has increased the vulnerability of natural ecosystems and brought a huge challenge to human being, how to adapt to climate change has become a hot spot in the world. The farmers who rely on natural resources for livelihoods is one of the vulnerable groups to adapt to climate change. Climate change has a serious negative impact on the farmers' livelihood, especially in the high-frigid ecologically vulnerable region. Perception of climate change is the basis of climate change adaptation, clearing the features of climate change perception of farmers is conducive to a better understanding of their response action. Selecting Gannan Plateau as the study area, based on 539 household survey data and the MPPACC (Model of Private Proactive Adaptation to Climate Change), built a index of the farmers' perception of climate change, this paper analyzes the features of farmers' perception to climate change and the key factors that affect the farmers' perception of climate change by using the econometric model. The results show that:(1) Farmers' perception of temperature change is more accurate than the perception of precipitation change,79.96% of farmers have sensed accurately the trend of rising temperatures over the past 30 years, which is consistent with the meteorological data, and only 36.92% of farmers have sensed the trend of rising precipitation, which is inconsistent with the actual meteorological data; At the same time, farmers have a deep memory of the influential and larger scale extreme weather that happened in recent years;(2) Farmers' severity perception, probability perception, adaptation efficacy perception and adaptation costs perception of climate change are strong, but the self-efficiency perception of climate change is weak, the index of their severity perception, probability perception, adaptation efficacy perception, self-efficacy perception and adaptation cost perception are 3.76, 3.34, 3.43, 2.85, 3.53 respectively. And these perception is the strongest in farming area, next in the planting-pasturing area, the pure pasturing area is the weakest.(3) Climate change information, farmer's objectively adaptive capacity, farmers' trust on the social discourse, and adaptation incentives are all affect the farmer's perception of climate change, among them, adaptation incentive is the key factors influence farmers' climate change perception, and the more adaptation incentives, the weaker farmers' severity perception, probability perception and adaptation costs perception, but the stronger farmers' adaptation efficacy perception and self-efficiency perception. Finally, we put forward some relevant policy recommendations, the purpose is improve the accuracy of farmers' perception to climate change and enhance their adaptive capacity.
  • DownLoad:Farmers' perception of climate change in high-frigid ecological vulnerable region: a case of Gannan Plateau.PDF
  • Ningbo atmospheric environment analysis and regulating countermeasure based on Urban Climatic Map
  • Authors:LIU Lele, ZHAO Xiaofeng, ZHAO Yanchuang and DENG Junjun
  • Abstract:Rapid urbanization has changed the urban climate and environment. As a result, many climatic and environmental problems have emerged. Valid urban climatic environment analysis and regulating countermeasures are required in order to cope with and mitigate these issues. An urban climatic map provides important guidance for the planning and regulation of the urban climatic environment. Based on a traditional urban climatic map, this research proposes a new method of building an urban climatic map that considers all seasons and multiple environmental elements. The urban area in Ningbo City, with its complicated underlying surfaces and obvious seasonal climate characteristics, was used as a case study. The technical means, including remote-sensing inversion, spatial analysis of geographical information system (GIS), and mesoscale numerical model simulation, were comprehensively applied to conduct a multi-season analysis and evaluation of the urban thermal load, air pollution, ventilation potential, wind field, and overall urban climatic environment. The results indicate that the spatial distribution of the urban thermal load and air pollutants is characterized by significant seasonal and spatial differences in the principal elements of the formation of an urban climatic environment. Ningbo City is affected by both thermal load and air pollution in spring and summer, affected only by air pollution in the winter, and only slightly affected by both thermal load and air pollution in the autumn. The spatial patterns of ventilation potential are similar in all seasons. Remarkable seasonal and spatial differences are presented, as the wind environment is complex and subject to change. By conducting an overall analysis on urban climatic environments, we found that areas with high and middle values of urban climatic environment are mainly distributed in forests, croplands, and water bodies. Areas with a high risk of urban climatic environment are located in the heavy chemical industrial zones along the coast of Beilun District, Zhenhai District, as well as the southern part of Hangzhou Bay. Areas with an intermediate risk of urban climatic environments are found in the regions where large amounts of industrial factories are clustered, such as the eastern Jiangbei District, eastern and western sides of Yinzhou District, Cixi urban area, and northeast part of the Fenghua urban area. Based on the above analysis, the planning schemes of urban ventilation channels and the regulating countermeasures of climatic environments are further proposed. These include two first-class ventilation channels, five second-class ventilation channels, three third-class bidirectional ventilation channels which are impacted by land-sea breezes, twelve third-class unidirectional ventilation channels which are impacted by land-sea breezes, thirteen third-class unidirectional ventilation channels which are impacted by mountain-valley breezes, and seven types of countermeasures for urban climatic environment regulation. The method of building an urban climatic map considering all seasons and multiple environmental factors raised by this research is applicable to the analysis and evaluation research of the monsoon climate zones with complicated climatic environments. It may also improve urban thermal load and atmospheric environmental quality and ease the problems of urban climatic environments in all seasons. It may do so through ventilation channel planning and formulating and implementing relevant regulatory countermeasures so as to provide support for urban environmental protection, meteorological and planning departments, and promote sustainable urban development and the construction of an ecological city.
  • DownLoad:Ningbo atmospheric environment analysis and regulating countermeasure based on Urban Climatic Map.PDF
  • Assessment of the influences of landscape fragmentation on regional habitat quality in the Manwan Basin
  • Authors:LIU Shiliang, YIN Yijie, YANG Juejie, AN Nannan, WANG Cong and DONG Shikui
  • Abstract:Dam construction and the subsequent land use change have obvious impacts on regional ecosystems. Not only the landscape pattern, but also the regional habitat quality are affected by these human activities. Taking the Manwan Basin of the Lancang River as a case study, habitat quality changes and key patch distributions of the whole study area and four sub-study areas (reservoir head zone, reservoir center zone, reservoir trail zone, and control zone) before and after dam construction were determined based on remote sensing images and GIS techniques, considering multiple factors (elevation, land use, and distance from water) and the dispersal ability of the focused species. The probability of connectivity index (PC) was a proxy for habitat quality in this study. Dispersal distances were set at 100, 300, 500, 700 m and 1000 m to calculate the PC index, which was further used to identify the importance level of habitat patches. The results showed that the degree of habitat fragmentation for macaques increased in the Manwan Basin, while the landscape connectivity between habitat patches and the percentage of key patches decreased after the construction of the Manwan hydropower plant. Regional habitat quality clearly declined, and the change in landscape pattern indicators in the four sub-study areas was similar to that in the total Manwan Basin. The PC index clearly decreased over time by about 55.51% on average, and there were 317.2 km2 of high-level patches converted to much lower levels from 1974 to 1991, while there were slight declines in the hydropower operation period. Habitat degradation occurred mainly in the south and west regions, especially in the reservoir tail zone, where patch number increased nine-fold while the landscape connectivity decreased by 81.48%. A linear-regression analysis indicated that the landscape connectivity index was positively associated with the percentage of landscape area index (R2=0.9729), but had a negative correlation with the patch number index (R2=-0.6106); Kendall's tau-b (τb) coefficient indicated that, except for the total edge index (TE), all of the other landscape pattern indicators (number of patches (NP), largest patch index (LPI), percentage of landscape index (PLAND), percentage of like adjacencies (PLADJ), connectance (CONNECT), and Shannon's diversity index (SHDI)) showed a remarkable correlation with landscape connectivity. It can be seen that the more serious the landscape fragmentation was, the more landscape connectivity and habitat quality were reduced. The percent increase in the dominant vegetation cover of habitats, which caused the PLAND to increase, can be an effective measure to restore the habitat quality. In addition, the protection of key patches and the construction of an ecological corridor, which would enhance the landscape connectivity, would contribute to the habitat quality recovery and the maintenance of landscape ecological functions.
  • DownLoad:Assessment of the influences of landscape fragmentation on regional habitat quality in the Manwan Basin.PDF
  • Measurement and empirical analysis of eco-efficiency in tourism destinations based on a Slack-based Measure-Data Envelopment Analysis model
  • Authors:PENG Hongsong, ZHANG Jinhe, HAN Ya, TANG Guorong and ZHANG Yu
  • Abstract:Many tourism destinations are characterized by interactions between people and the environment. Typically, research on the eco-efficiency of tourism destinations is the basis for the formulation and implementation of inclusive, sustainable development policies and measures. Extensive literature is available on the eco-efficiency evaluations of the environmental impact of human material production behavior, such as industry and manufacturing, but studies exploring tourism from the perspective of human consumption behavior are limited. Little systematic research has been conducted to investigate the eco-efficiency theoretical system and the calculation methods involved, with more attention paid to large-and medium-scale regional or urban cases. Small regional-scale cases, especially tourist destinations, are yet to be explored. Based on a time series Slack-based Measure-Data Envelopment Analysis (SBM-DEA) model, including unexpected output, we built a model to measure the eco-efficiency of tourism destinations and an evaluation index system. We selected the average wage level, new fixed asset investments, energy consumption, water consumption, and catering biological resource consumption as input indicators. Per capita tourism income was selected as the expected output indicator, and the emission indicators of tourism waste, namely, the amount of garbage, sewage, and waste gas emissions, were used to characterize the unexpected output indicators. We chose the Huangshan scenic area as an example and used the input and output data from 1981 to 2014 to measure the eco-efficiency of the tourist destination composite system and analyzed its evolution characteristics and phases. We used a Tobit regression model to empirically test the influencing factors. First, we explored the characteristics and the evolution of the eco-efficiency of the tourism destination; next, we distinguished the key factors that influenced this eco-efficiency and investigated the relationships between tourism eco-efficiency, tourism investment, and output factors. The following results were obtained:(1) In the past 34 years, eco-efficiency (technical efficiency) has grown continually in the Huangshan scenic area, which has a great development potential. Pure technical efficiency is the most influential, followed by scale efficiency, for decomposition. Scale efficiency is a decisive factor for technical efficiency. (2) The evolution of tourism ecological efficiency has four stages:initial inefficient stage, rapid growth stage, mature efficient stage, and downside risk stage. The eco-efficiency characteristics and influencing factors in different stages are different. (3) Tourism eco-efficiency is complete when scale transition returns from an increase to a decrease. Thus, the input redundancy of resources becomes the key factor preventing ecological efficiency from improving further in the present stage. (4) The level of tourism development, industrial structure, and technical level have a significant positive impact on eco-efficiency, but investment levels have a significant negative impact. The environmental regulation that emphasizes the management of waste is not effective in promoting eco-efficiency. This study proposed that the scale of resource inputs should be expanded as far as possible at the beginning of the mountain-type scenic area development. When the destination enters the mature stage, the investment scale should gradually be controlled. This involves improved technology and resource allocation, abandoning the extensive development pattern that results in overdependence on resource consumption and environmental pollution. The study contributes to related research perspectives and methods and promotes the sustainable development of tourism destinations.
  • DownLoad:Measurement and empirical analysis of eco-efficiency in tourism destinations based on a Slack-based Measure-Data Envelopment Analysis model.PDF
  • Global warming and droughts aggravates forest damage resulting from pests and diseases in Jiangxi Province
  • Authors:ZHANG Pengxia, YE Qing, OUYANG Fang, PENG Longhui, LIU Xingping, GUO Yuehua and ZENG Juping
  • Abstract:Over the past 50 years, the climate has changed rapidly with global warming and land surface drying, which has been accompanied by increased forest loss and damage resulting from pests and diseases. Climate data (e.g., air temperature, relative humidity, and sunshine data) from 1961 to 2010 showed that the climate in the Jiangxi Province was warming significantly, with the annual mean temperature increasing by 0.16℃ per 10 years, and the winter mean temperature rising by 0.27℃ per 10 years. The Jiangxi Province climate was also drying throughout this period (annual mean relative humidity decreased -0.45% per 10 years). In addition, forest pests and disease occurrence from 1992 to 2010 showed that in Jiangxi, the area affected by of forest diseases and pests increased significantly, with 58,125 hm2 per 10 years. Pearson correlation and principal component analyses showed that 16 (for forest diseases) or 17 (for forest pests) climate elements were significantly related to the forest loss. From these individual elements, the most positively correlated was a 9-year sliding average of summer mean temperature, and the most negatively correlated component was a 9-year sliding average of hydrothermal coefficient (annual mean temperature/annual mean relative humidity). Amongst the four or five principal components, the variables temperature and temperature-humidity contributed most to explaining forest area loss (41.43% and 42.0%, respectively). In stepwise regression analyses, three optimal regression models (Total:Y=3.582×106 -7.750×105X, forest pest:Y=-6.375×105X+2.95×106, forest diseases:Y=-1.375×105X+6.321×105) were analyzed to describe the forest loss (Y) by the 9-year sliding average of temperature humidity coefficient (X). The three models showed a linear fit of 77.9%, 79.1%, and 56.7% and a prediction accuracy of 66.2%, 68.6%, and 47.9%, respectively. A declining trend in the sliding average of temperature humidity coefficient was observed over the past 50 years, for which the anomaly transferred from positive to negative in 1993. This indicates that climate warming and droughts could have aggravated the forest loss and damage over the past 50 years, especially after 1990s. A wavelet analysis showed a 29-year periodicity in the temperature humidity coefficient. If this anomaly started in 1993, the forest loss trend could potentially be relieved by the end of 2022. In Jiangxi, the temperature humidity coefficient significantly increases from the south to the north, suggesting that forest diseases and pest disasters should be more extreme in Gan Nan than in other areas. In addition, since the change rate of climate warming or drought was higher in Gan Dong and Gan Bei, a high variability of forest diseases and pest disasters can be expected there in the future. Overall, our results suggest that climate warming and environmental drought aggravates forest diseases and pest disasters in Jiangxi. They furthermore emphasize that Gan Nan could be a key area in preventing and controlling the effects of forest diseases and pest disasters, whereas the monitoring efforts in Gan Dong and Gan Bei should be increased.
  • DownLoad:Global warming and droughts aggravates forest damage resulting from pests and diseases in Jiangxi Province.PDF
  • Ecological control of the Asian corn borer, Ostrinia furnacalis (Guenée) by two cloned Beauveria bassiana strains
  • Authors:FENG Shudan, LI Xiaohui, WANG Yangzhou, ZHANG Jun, XU Wenjing, ZHANG Zhengkun, WANG Deli and LI Qiyun
  • Abstract:Ecological control methods are important for controlling agricultural pests. The Asian corn borer (ACB), Ostrinia furnacalis (Guenée), has been an extremely serious pest, that cause severe reduction in corn yields. The ubiquitous entomopathogenic fungus Beauveria bassiana has been used to suppress populations of the European corn borer (ECB), O. nubilalis, and ACB globally. Most studies have focused on the application of B. bassiana, with limited studies on the relationship between the fungus, corn, and insects. Our previous research indicated that B. bassiana with two mating-gene types, MAT1-1-1 and MAT1-2-1, could colonize corn. These mating-type genes had mutation sites cloned from endophytic fungal strains, which revealed corn plants and insects could impact fungal evolution. The purpose of the present study was to create endophytic symbiosis and determine the interaction among B. bassiana (entophytic fungus), corn plants, and ACB. We created a B. bassiana-corn endophytic symbiosis by inoculating two mating-gene type B. bassiana strains (MAT1-1-1 type B5 and MAT1-2-1 type B2) into corn plants in a suspension with a concentration of 1×107 spores/mL. The effect of endophytic symbiosis on the growth of corn plants, oviposition preference of ACB adults, development of ACB larvae, and biological variation of B. bassiana were evaluated in the greenhouse. The results showed that endophytic B. bassiana could be detected from corn leaves in vitro by culture. ITS and mating-type gene amplification and sequencing confirmed the successful creation of endophytic symbiosis. The MAT1-2-1 type B2 treatment group showed a higher endophytic detection rate than MAT1-1-1 type B5, whereas MAT1-1-1 type B5 was more successful during co-inoculation than MAT1-2-1 type B2. The variation of the colony diameter and virulence of the recovered B. bassiana were not significant, but the sporulation quantity improved significantly, and the EN-B5 strain (recovered from the B5 treatment) changed the most obviously. The height of corn plants and dried biomass of treatment groups were higher than the CK group, while the underground root biomass significantly improved. The B5 strain contributed more to above-ground plant height and the B2 strain contributed more to underground root biomass. ACB moths were released into nylon-meshed cages. Egg quantity showed a significant difference in all treatment groups, which was lower than that in the CK group. Egg fecundity rate in the B2 group was 3.33%, but 53.33% in the CK group; therefore, the B2-corn endophytic symbiosis group was not the preferred host for ACB egg laying. The ACB larval survival rate and weight in treatment groups were significantly lower than those in the CK group. The ACB pupation rate of treatment groups was not significantly lower than that of the CK group, but there was a significant difference between B5 and B2 groups; the B5 group had the lowest survival (38.33%) and pupation rates (34.77%). These results demonstrated that the sporulation quantity of the recovered B. bassiana strains significantly improved, and the synergism of the two strains with different mating-type genes was shown. The two B. bassiana mating-types could colonize in corn plants and mutualistic endophytic symbiosis was formed, which reinforced corn growth and improved the resistance against pests. B. bassiana-corn endophytic symbiosis is important for the sustainable management of pests by inhibiting oviposition and suppressing larval and pupal development. The results also proved that mutualistic symbiosis could improve the ecological adaptability of B. bassiana and corn, which offered a new strategy for ACB control using endophytic symbiosis through the application of B. bassiana.
  • DownLoad:Ecological control of the Asian corn borer, Ostrinia furnacalis (Guenée) by two cloned Beauveria bassiana strains.PDF
  • Spatial and seasonal variability of the zooplankton community in the Yellow River Estuary's adjacent sea
  • Authors:DONG Zhijun, YANG Qing, SUN Tingting, WANG Yujue, JIANG Huichao and LIU Dongyan
  • Abstract:The unusual dynamic conditions in estuaries cause their zooplankton distribution, as well as the zooplankton distribution in the adjacent sea, to be spatially and temporally heterogeneous. To investigate this heterogeneity in the adjacent sea of the Yellow River Estuary, zooplankton samples were collected from there in December 2012, April 2013, June 2013, and September 2013. The samples were collected using a plankton net with mesh size 0.160 mm, while during the four cruises, environmental parameters such as seawater temperature, salinity, and chlorophyll a concentration were determined. Spearman rank correlations were used to analyze the relationship between zooplankton abundance and various environmental factors. Overall, 70 zooplankton species were identified, including 19 pelagic larvae. The copepods were the most abundant group, representing 30%, followed by hydromedusae. For the study region, the most dominant organisms were Noctiluca scintillans, Paracalanus parvus, Acartia bifilosa, Oithona similis, Paracalanus crassirostris, Corycaeus affinis, Sagitta crassa, Bivalvia larvae, and Polychaeta larvae. Among these, P. parvus, A. bifilosa, and O. similis dominated the zooplankton communities for three of the measured seasons. Furthermore, the composition of dominant species varied with seasons, with the seasonal turnover rate of dominant zooplankton species being high (67%-88%). The abundance of P. parvus averaged 9320 ind/m3 in summer, 3704 ind/m3 in autumn, 3891 ind/m3 in winter, and 165 ind/m3 in spring. For the Yellow River mouth, P. parvus reached the greatest abundance in summer, while for the eastern sea area, this occurred in autumn and winter. Furthermore, the abundance of A. bifilosa averaged 40218 ind/m3 in summer, 17815 ind/m3 in spring, and 2127 ind/m3 in winter. In spring, the abundance of A. bifilosa showed a decreasing trend from the Yellow River mouth to the outer sea area. For the Yellow River mouth, this species reached its highest abundance in summer, whereas for the eastern sea area, this occurred in winter. In addition, the abundance of O. similis averaged 4245 ind/m3 in summer, 2776 ind/m3 in spring, 1154 ind/m3 in winter, and 88 ind/m3 in autumn. In spring, O. similis reached the highest abundance in the both sides of the Yellow River mouth, while for the Yellow River mouth this occurred in summer and for the eastern sea area in winter. N. scintillans dominated the zooplankton community in spring and summer. The abundance of N. scintillans averaged 28194 ind/m3 in spring and 13679 ind/m3 in autumn. In spring, N. scintillans reached the highest abundance in the southern area of the Yellow River mouth, whereas for the eastern sea area, this occurred in autumn. Overall zooplankton abundance averaged 60620 ind/m3 in summer, 31228 ind/m3 in spring, 21540 ind/m3 in autumn, and 7594 ind/m3 in winter, while its spatial distribution varied among the four seasons. In spring, zooplankton abundance showed a decreasing trend from the Yellow River mouth to the outer sea area. In summer, zooplankton density was higher in the Yellow River mouth and the eastern sea area. The higher zooplankton abundance occurred in the eastern sea area in autumn and winter. The zooplankton community's diversity index (H') showed an increasing trend from the Yellow River mouth to the outer sea area. Finally, the zooplankton abundance had a clear positive correlation with the seawater temperature (r=0.212, P < 0.05), suggesting that for the Yellow River Estuary, seawater temperature was one of the main factors determining zooplankton abundance.
  • DownLoad:Spatial and seasonal variability of the zooplankton community in the Yellow River Estuary's adjacent sea.PDF
  • Habitat suitability of Stichopus japonicas, Scapharca broughtonii and Mytilus edulis in the shallow waters of Xiaoheishan Isalnd
  • Authors:TANG Liuqing, WANG Qixiang, LIU Hongjun, ZHANG Zhipeng, LIU Chengyue and ZHOU Jian
  • Abstract:Xiaoheishan Island is located in Bohai Strait and affiliated with Miaodao Archipelago, which lies in Shandong province. The paper identifies the potential area for sustainable restoration of Stichopus japonicas, Scapharca broughtonii and Mytilus edulis in the shallow waters of Xiaoheishan Island using a habitat suitability index model (HSI). Seven screened environmental factors were involved in the HSI model for each species respectively. In summary, the following 9 factors:water temperature, salinity, water depth, pH, sediment composition, dissolved oxygen, organic carbon, current velocity and Chlorophyll a were analyzed in this study. Specific factor piecewise functions have been used to transform environmental factor values into normalized quality indexes (0, 2, 3 and 4). The weight of the each factor was judged with the expert knowledge and the analytic hierarchy process (AHP) method. Thus, the habitat suitable analysis maps were obtained after data interpolate, reclassification and raster calculation with the aid of GIS spatial analysis module. In addition, the analysis of habitat suitability was conducted for four seasons in this paper in order to get more detailed information. First, the results suggest that the entire area was suitable for restoration of S. japonicas and M. edulis, along with no spatial differences but obvious seasonal changes for the 2 species. For S. broughtonii, it is noteworthy that the study area was defined as the suboptimal habitat by the reason of aestivation. Moreover, the northeast region was detected as the optimal site for S. broughtonii propagation, followed by the western part. Meanwhile, the suboptimal habitat accounted for the majority of study area throughout the year with the marginal habitat only appeared in winter. Water temperature was the main factor causing seasonal variation, while sediments composition was remained as the key reason for the differences in habitat sites. Overall, the results indicated the great feasibility for the long-term survival and successful restoration of S. japonicas, S. broughtonii and M. edulis. This study could provide supports and suggestions for subsequent research of biological diversity protection and ecological restoration.
  • DownLoad:Habitat suitability of Stichopus japonicas, Scapharca broughtonii and Mytilus edulis in the shallow waters of Xiaoheishan Isalnd.PDF
  • Seasonal variation in zooplankton community structure in the Changjiang Estuary and its adjacent waters
  • Authors:SHAO Qianwen, LIU Zhensheng, ZHANG Jing, SUN Dong and LIN Shiquan
  • Abstract:Seasonal variation of zooplankton community structure, species composition, and dominant species were determined based on samples collected from 150 stations during four research cruises in the Changjiang Estuary and its adjacent waters (29°30'N-32°30'N,120°00'E-127°30'E). The study was conducted from July to August 2006 (Summer), December 2006 to February 2007 (Winter), April to May 2007 (Spring), and October to December 2007 (Autumn). The mesoscale study areas were positioned from the Changjiang Estuary to the transition area where freshwater from the Changjiang plume and offshore water masses, such as the Kuroshio and its branches, mix with each other. In total, 460 species of zooplankton belonging to 246 genera and 18 groups from seven phyla, together with 54 types of pelagic larvae, were identified in the Changjiang Estuary and its adjacent waters during four seasons. The 18 groups of zooplankton included Hydromedusae, Siphonophora, Scyphomedusae, Ctenophora, Polychaeta, Cladocera, Copepoda, Ostracoda, Isopoda, Mysida, Cumacea, Amphipoda, Euphausiacea, Decapoda, Chaetognatha, Appendicularia, Thaliacea, and pelagic Mollusca. The most dominant group of zooplankton was Copepoda, including 193 species and accounting for 41.96% of the total species. Amphipoda ranked second, with 51 species accounting for 11.09% of the total species. Hydromedusa was the third dominant group of zooplankton with 34 species and accounted for 7.39% of the total species. There was considerable seasonal and spatial variation in the community structure of zooplankton in the Changjiang Estuary and its adjacent waters. More zooplankton species were found in summer (317 species and 43 types of pelagic larvae) and autumn (309 species and 28 types of pelagic larvae) than in spring (230 species and 27 types of pelagic larvae) and winter (138 species and 21 types of pelagic larvae). The number of species increased gradually from the inshore to offshore waters and from north to south, during all seasons. There were seasonal changes in dominant species in the Changjiang Estuary and its adjacent waters:in spring and winter, Calanus sinicus was the most dominant species, but in summer and autumn, the most dominant species was replaced by Centropages dorsispinatus and Subeucalanus subcrassus, respectively. Only Calanus sinicus and Zonosagitta bedoti were dominant in all four seasons. Based on species composition and ecological distribution, the zooplankton community in the Changjiang Estuary and its adjacent waters could be divided into five ecological groups, including the coastal brackish water, eurythermal euryhaline, hypothermal hypersaline, hyperthermal euryhaline, and hyperthermal hypersaline group. The dominant species were distributed primarily in the coastal brackish water group and eurythermal euryhaline group. Furthermore, we measured environmental factors and determined the responses of the zooplankton community to the factors, including temperature, salinity, concentration of suspended matter, and concentration of chlorophyll a. Results of Pearson's correlation analysis revealed that the most important environmental factor influencing changes in zooplankton community structure in the Changjiang Estuary and its adjacent waters was salinity. Furthermore, the Changjiang diluted water introduced a large number of nutrients, which was beneficial to the growth of plankton, but the estuarine turbidity limited the distribution of zooplankton.
  • DownLoad:Seasonal variation in zooplankton community structure in the Changjiang Estuary and its adjacent waters.PDF
  • Effects of water temperature and salinity on oxygen consumption rate and ammonia excretion rate of Saccostrea cucullata
  • Authors:JIAO Haifeng, ZHENG Dan, YAN Qiaona, YOU Zhongjie and YAN Xiaojun
  • Abstract:Intertidal oyster (Saccostrea cucullata) is an important cultivated species and macro-fouling organism in the southeastern China Sea, and it is an important model organism for studies on shellfish physiology and marine ecology. Oxygen consumption rate and ammonia excretion rate are important parameters of shellfish physiology and metabolism, and can be measured as sensitive indicators of pollutant toxicity. However, little is known about the effects of environmental factors affect oxygen consumption rate and ammonia excretion rate of Saccostrea cucullata. The effects of water temperature (13, 18, 23, 28, 31, 34℃) and salinity (18, 23, 28, and 33) on oxygen consumption rate and ammonia excretion rate in Saccostrea cucullata were analyzed using experimental ecological methods. Oxygen consumption rate varied from 0.43 mg g-1 h-1 to 3.15 mg g-1 h-1 and the ammonia excretion rate varied from 72.62 μg g-1 h-1 to 1245.77 μg g-1 h-1 in different water temperature. Water temperature and salinity significantly affected oxygen consumption rate (F=60.440) and ammonia excretion rate (F=61.083); additionally, the combination of water temperature and salinity affected oxygen consumption rate (F=4.907) and ammonia excretion rate F=11.412). Temperature varied from 13 to 31℃ and salinity varied from 18 to 28, and the relationship between oxygen consumption or ammonia excretion rate (Y) and temperature (T) and salinity (S) can be represented by the equation Y=a+bT+cS+dT×S. The relationship between oxygen consumption rate (Y) and water temperature (T) can be described by the regression equation:Y=aebT, where a ranges from 0.1378 to 0.2117, and b ranges from 0.0757 to 0.0912. The relationship between ammonia excretion rate (Y) and water temperature (T) can also be described by the regression equation:Y=aebT, where a ranges from 20.364 to 30.634, and b ranges from 0.1044 to 0.1341. The atomic ratio of O and N varied from 2.20 to 7.78, with a mean of 3.81 to maintain standard metabolism in Saccostrea cucullata.
  • DownLoad:Effects of water temperature and salinity on oxygen consumption rate and ammonia excretion rate of Saccostrea cucullata.PDF
  • Fish invasions and changes in the fish fauna of the Tarim Basin
  • Authors:CHEN Guozhu, QIU Yuping and LI Liping
  • Abstract:Many native fish species in the Tarim Basin are endangered, owing to the invasion of alien fish species over the past decades. To better understand how to protect native fish and control the spread of alien fish, the number of alien fish species in the Tarim Basin and their potential ecological effects on native fish species should be assessed. In the present study, we used Jaccard's Index of similarity to investigate the homogenization of fish fauna between the Tarim Basin and associated regions. Furthermore, we adopted the fish autecology matrix to test whether invasive fish would be able to spread widely in the Tarim Basin in the near future. These data were collected from the literature and from field investigations performed in recent years. Our results showed that a total of 63 fish species have been recorded in the Tarim Basin, including 19 native and 44 alien species. The introduction of alien fish species increased species, genus, and family diversity. However, the G-F diversity index (the ratio of genus diversity index and family diversity index) has decreased. The introduction of alien fish to the Tarim Basin is suggested to have changed the species composition from simple and highly differentiated to complicated and poorly differentiated. Moreover, among 44 alien species, 39 (68.2%) were originally from the middle and lower Yangtze River, 7 (15.9%) were originally from the Ertix River, and 7 (15.9%) were originally from America, Europe, and other regions of Asia. We also found that the index of similarity of fish fauna between the Tarim Basin and associated regions significantly increased before and after the introduction of alien species (P < 0.01), indicating that alien species caused homogenization of the fish fauna within the studied regions. Furthermore, the fish autecology matrix revealed that alien fish species can be well adapted to the habitats of the Tarim Basin, and can cause the decline of native fish species through predation and competition. Therefore, control measures against alien fish should be implemented and/or intensified in order to protect the native fish species of the Tarim Basin.
  • DownLoad:Fish invasions and changes in the fish fauna of the Tarim Basin.PDF

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