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Volume 38,Issue 16
  • Source identification and meteorological analyses of the early immigration of Nilaparvata lugens into Yunnan Province, China
  • Authors:BAO Yunxuan, SHANG Jie, SUN Sisi, XIE Xiaojin, LU Minghong and LIU Wancai
  • Abstract:Ten-year observational data for the brown plant hopper (BPH), Nilaparvata lugens (Stål) at six plant-protection monitoring stations in Yunnan Province are presented to determine the sources of BPH, at the time of their early immigration into the rice-planting areas of Southwestern China, in April and May from 2007 to 2016. The six stations included in the study were Mangshi, Menghai,Jiangcheng, Shizong, Malipo, and Guangnan. These observational analyses were then used to provide scientific evidence in support of the migration predictions for BPH and measures for its prevention. The Flexible Particle Dispersion (Flexpart) model driven by the Weather Research and Forecast Model (WRF) outputs was used to simulate the early immigration peaks observed at these stations in 2013, 2015, and 2016 and then identify their sources. A detailed analysis of the data obtained for 2013 was conducted to determine the atmospheric dynamics, temperature, and relative humidity conditions during the early immigration of BPH in Yunnan Province. The BPH that had early immigration in Yunnan Province in these years were mainly from Myanmar, partly from Laos and Thailand, a few from Vietnam, and very few from Bangladesh. The prevailing (average) migration heights of BPH at 2216 m (2167 m) and 2489 m (2454 m) corresponded to the release heights of 1500 m and 2000 m, respectively. Good agreement between the model backward trajectories and the BPH migrating heights indicates that the model was able to capture the impact of systematic vertical airflows and the complex underlying surface on group migrations. A typical case study of an immigration event of BPH observed in Menghai, Malipo, and Guangnan in Yunnan Province from May 22nd to 26th in 2013 further demonstrates that the immigration of BPH from abroad at upper levels into Yunnan Province was mainly driven by the southwest prevailing winds associated with the Indo-Burma low pressure system; the low-temperature zone was a barrier preventing continuous northward migration over the Northeast landing areas of the BPH; and the BPH migration behaviors were highly associated with vertical motions. While the updraft was responsible for the taking-off and moving out, the downdrafts corresponded to BPH descent; the dragging effect of subsidence associated with weak rainfall was favorable this descent, whereas the relative humidity field had limited impact on the migration of BPH populations during this event.
  • DownLoad:Source identification and meteorological analyses of the early immigration of Nilaparvata lugens into Yunnan Province, China.PDF
  • Metacommunity patterns of ground-beetle assemblages in two mixed broad-leaved Korean pine (Pinus koraiensis) forests in the Xiao Xing'an Mountains
  • Authors:GAO Meixiang, ZHANG Chao, QIAO Zhihong, HOU Hongyu, JIN Guangze, LU Tingyu and WU Donghui
  • Abstract:A metacommunity is defined as a set of local communities that are linked by the dispersal of multiple potentially interacting species. Metacommunity theory framework provides a powerful method for the understanding of spatio-temporal patterns and explaining the underlying processes of a community structuring. Metacommunity framework has been used in various organism communities (including plant, bat, arbuscular mycorrhizal fungi, bird, and invertebrate communities). However, few studies have been used to recognize the metacommunity patterns and their underlying processes for soil animal communities at multiple scales, especially at small scales. In 2015, an experiment was conducted in two permanent dynamic monitoring plots in two typical mixed broad-leaved Korean pine (Pinus koraiensis) forests in the Liangshui (LS) and Fenglin (FL) National Nature Reserves. Each plot consisted of a 9-hm2 area with 300 m×300 m and was equally divided into 225 squares by 20 m. Based on a spatially explicitly investigating method, ground beetles were collected by pitfall traps in July, August, and October in the LS plot and in August and October in the FL plot. The topographic variables, that is elevation, slope convexity, slope steepness and slope aspect, were measured for each square both in LS and FL plots. The soil variables, including bulk density, soil organic carbon content, total nitrogen, available phosphorus, total phosphorus, pH, available potassium, hydrolyzable nitrogen and soil moisture, were measured for each square in LS plot. The metacommunity patterns of ground beetles were determined by elements of metacommunity structure (EMS). We evaluated if the Clementsian pattern is common for ground beetle metacommunities at such small scales. Then we explained the association between the site scores along the first axis of the reciprocal averaging and geographic and/or soil variables by Spearman rank correlation. Results of the EMS showed that nestedness and random patterns were common for ground beetle metacommunities at small scales, such as in the two studied typical mixed broad-leaved Korean pine forests. The Clementsian pattern was not detected for any ground beetle metacommunity. Moreover, metacommunity patterns of ground beetles were group-dependent. Metacommunity patterns were nestedness for Carabid and Silphidae beetles, while metacommunity patterns were random for Staphylinidae beetles. At the same time, metacommunity patterns of ground beetles were seasonal dynamic. The nestedness patterns were formed in warm seasons (i.e. July and August), and the random patterns were formed in a relatively cool season (October). Metacommunity patterns between the LS and FL plots were not significantly different. The site scores along the first axis of the reciprocal averaging were correlated with topographic and/or soil variables for Carabid, Silphidae, and total beetle communities. Important factors included mean elevation, aspect, slope, total nitrogen, pH, and soil organic matter content. These variables were suggested influences on ground beetle metacommunity patterns. However, the influences were relatively complicated and were group-dependent and season-dependent. This study suggests that nestedness and random patterns are common for ground beetle metacommunities at small scales in the typical mixed broad-leaved Korean pine forests in the Xiao Xing'an Mountains. Additionally, topographic and soil variables may be important factors for formatting these metacommunity patterns.
  • DownLoad:Metacommunity patterns of ground-beetle assemblages in two mixed broad-leaved Korean pine (Pinus koraiensis) forests in the Xiao Xing'an Mountains.PDF
  • Assessment of the changes in the number of terrestrial vertebrates and habitat in Northeast China over the last 40 years
  • Authors:WAN Huawei, XIA Lin, HOU Peng, LIU Yuping, CAI Lei, PENG Huifang, ZHAO Shuhui, YANG Qisen, SUN Chenxi and XU Xinliang
  • Abstract:Biodiversity is the basis for maintaining ecological balance and realizing ecological process and function. Northeast China is one of the most biodiverse areas in China and even the whole world. To understand the changes of the number and habitats changes of terrestrial vertebrates in the Northeast China, we combined long time-series species survey data and habitat remote sensing data, selected living planet index (LPI), area and fragmentation index of ecosystem types in different years as indicators, assessed the variation trend of terrestrial vertebrates and habitats in Northeast China in recent 40 years. The study showed the number of terrestrial vertebrate reduced by 70.1% from 1970 to 2010 in this area. The number of forest species reduced by 80.9% and the number of grassland and desert species increased by 180.9% from 1970 to 2010. The number of wetland species reduced by 75.7% from 1980 to 2010. The area of farmland and urban development increased by 25.2% and 32.3% from 1980 to 2015, respectively. With the continuous erode of natural ecological space such as reclamation of agriculture and urbanization, about 6.1% of the natural habitats were converted to artificial habitats. As a result, the natural habitats continued to decrease with a total decrease of about 8.0% in the area. The landscape fragmentation index of the natural habitat overall showed an increasing trend during 1980-2015. In particular, the index of fragmentation of forest habitats increased by about 42.7%, but the rising trend was lower after 2005, which was consistent with the decreasing trend in the number of vertebrate populations after 2005. This study showed that the number of large mammals in Northeast China has decreased sharply in the past 40 years, and the main reasons for this change are the increase in fragmentation of natural ecosystems and the decline of habitat quality caused by deforestation, population growth, urbanization, and traffic construction.
  • DownLoad:Assessment of the changes in the number of terrestrial vertebrates and habitat in Northeast China over the last 40 years.PDF
  • Studies on the movement, home range, and habitat use of greylag geese (Anser anser) based on satellite tracking
  • Authors:MENG Weiyue, LI Shuhong, ZHOU Jingying, QIAN Ying, WEI Xiuhong, HAN Morigen, DAI Qiang, LU Jun, ZHU Siyu and ZHANG Guogang
  • Abstract:The accumulation of nutrition and energy is an important factor for the migration of migratory birds. To understand how greylag geese obtain energy to meet the physiological demands of fall migration, we studied the movement, home range and habitat use of graylag geese by using satellite tracking from August to October 2015 in the Tumuji wetland of Inner Mongolia. The enhanced vegetation index (EVI) was used to analyze habitat use, the sizes of the day and night home ranges were determined using kernel density estimation (KDE), and the average activity distances in different months were analyzed. The EVI of the locations of the greylag geese decreased from August to October, the geese gradually dispersed southward and concentrated around the area with abundant water, and they preferred the lakes to the grassland. The home range size of the geese increased from August to October and the home range size was larger in daytime than at night. The movement distances of greylag geese were higher during the day, especially for the peak of movement before dawn and at dusk. Because the temperature decreased gradually from August to October, the potential food resources in grassland declined, and greylag geese tended to occupy the areas with more abundant water, which gradually increased both the home range size and the movement distances, thus enabling the geese to efficiently obtain sufficient nutrition and energy to meet the physiological demand of fall migration.
  • DownLoad:Studies on the movement, home range, and habitat use of greylag geese (Anser anser) based on satellite tracking.PDF
  • Biological mechanisms of typhoon-induced blooms in the South China Sea
  • Authors:ZHANG Yafeng, WANG Xutao and YIN Kedong
  • Abstract:Phytoplankton growth and micro-zooplankton grazing are regulated by temperature, nutrients, and light in the ocean. Because of the different vertical distributions of light and nutrients, there is often a deep chlorophyll maximum (DCM) layer in the water column, which is widespread and almost a permanent ecological structure in the tropical oligotrophic ocean because of the stable stratification of the water column. Most parts of the South China Sea (SCS) are oligotrophic with strong underwater irradiance and low surface layer nutrients due to the stratification. The nutrient level is too low to support a phytoplankton bloom in the surface water, however, there are numerous reports of bloom events in the SCS after typhoonsevery year. It is commonly accepted that vertical mixing can weaken the nutricline and bring deep nutrient-rich waters to the euphotic zone, fueling phytoplankton blooms in the euphotic zone. However, few studies have compared the responses of phytoplankton and micro-zooplankton to the fluctuations of light intensity and pulses of nutrients simultaneously. In this study, an incubation experiment was conducted in the basin of the SCS during a cruise to compare the responses of surface and DCM phytoplankton to elevated irradiance and nutrients. Additionally, dilution experiments in different nutrient and irradiance conditions with surface and DCM water samples were conducted to explore micro-zooplankton grazing activity and their roles in the surface and DCM layers. We hypothesized that the DCM phytoplankton could be the seed population when the deep water is mixed upward with the surface layer in the case of a typhoon due to the changes in irradiance and micro-zooplankton grazing activity. The experimental results showed 1) micro-zooplankton grazing rates in the surface water were significantly higher than those in the DCM, and micro-zooplankton in the surface layer preferred the large size phytoplankton (>5 μm), whereas there was no such size selection in the DCM layer; UVR could promote the grazing rate of micro-zooplankton, whereas nutrient additions slightly decreased it; 2) the DCM phytoplankton assemblage responded more rapidly to the nutrient and light supplements and reached higher maximum biomass than surface phytoplankton, and the finial dominating size was larger in the DCM layer than that in the surface water. Therefore, the DCM phytoplankton assemblage is under less micro-zooplankton grazing intensity, and is more sensitive to light and nutrients. These results prove the hypothesis that DCM phytoplankton are seed populations when the deep water is mixed upward with the surface layer in a typhoon.
  • DownLoad:Biological mechanisms of typhoon-induced blooms in the South China Sea.PDF
  • Study on the competition and community succession of phytoplankton cultivated with organic phosphorus
  • Authors:SU Yuping, ZHANG Lixiang, CHEN Yangfeng, LI Helong, SHE Chenxing and DENG Yao
  • Abstract:Phosphorus is an essential element for phytoplankton growth and also one of the key factors in eutrophication control. In oligotrophic waters with limited phosphorus, algal species which can effectively utilize the organic phosphorus are likely to dominate in the phytoplankton community structure. To study the effects of organic phosphorus on the succession of the phytoplankton community structure, we collected water samples from three reservoirs:Xipi Reservoir (Bacillariophyta, 70.3%;Pyrrophta, 19.1%; Chlorophyta,9.3%), Shanmei Reservoir (Bacillariophyta, 31.3%;Pyrrophta, 59.2%; Chlorophyta, 3.5%) and Thirty-Six-Feet Lake (Bacillariophyta, 43.1%; Pyrrophta, 50.5%;Chlorophyta, 5.0%). For comparing to an inorganic phosphorus source (NaH2PO4·2H2O), we used the adenosine monophosphate (AMP) as an organic phosphorus source for a 20-day cultivation, and discussed the variation in the growth and the succession of the phytoplankton community structure. The results illustrated different increasing rates of the phytoplankton biomass in Xipi Reservoir (6.5-fold), Shanmei Reservoir (2.1-fold) and Thirty-Six-Feet Lake (1.9-fold). Pyrrophta and Chlorophyta became the dominant phytoplankton groups with AMP as the phosphorus source, and their relative abundances were 81.8% and 16.7% in Xipi Reservoir, 55.2% and 33.5% in Shanmei Reservoir, and 73.2% and 24.3% in Thirty-Six-Feet Lake respectively. In Xipi Reservoir, Peridiniopsis Lemmermann had the highest utilization capacity for AMP, and its relative abundance reached 81.8%. Our work suggested the strong promotion of AMP in the proliferation of Peridiniopsis Lemmermann in Pyrrophta, contributing to the variation in the phytoplankton community structure.
  • DownLoad:Study on the competition and community succession of phytoplankton cultivated with organic phosphorus.PDF
  • Comparison of macroinvertebrate community structure among typical upstream habitats in the Newxue River
  • Authors:CHEN Jing, JIANG Wanxiang, WANG Hongkai, WANG Hongmei, CHEN Qing, HE Shishui and ZHUO Liling
  • Abstract:Understanding community spatio-temporal variability is the basis for further research (such as trait, functional diversity, and so on). Most studies to date have focused on the relationship between community structure and environmental factors, and species composition has been only rarely reported. In the present study, macroinvertebrate community structure was compared among typical stream habitats in the upper Newxue River in the year 2012 (April, October, and December). The main results were as follows:a total of 108 macroinvertebrates taxa belonging to 74 genera and 10 Classes were recorded; Cheumatopsyche sp., Orthocladius vaillanti,Paratanytarsus sp.E, and Neozarelia sp. were the dominant taxa, with relative abundances of 25.1%, 9.8%, 9.0%, and 8.6%, respectively. Dominant taxon composition, density, biomass, ratio of biomass and density, and biodiversity indices (richness, Shannon index, and evenness index) were significantly different among different reaches. Non-metric multidimensional scaling (NMS) and multiple response permutation procedure (MRPP) showed that community structure was significantly different among the reaches, and this difference increased with decrease in flow rate. Indicator species analysis and two-way cluster analysis were used to explain the reasons for differences in community structure at the species level. The protection of habitat diversity is thus of great significance for the protection and improvement of biodiversity in the study area.
  • DownLoad:Comparison of macroinvertebrate community structure among typical upstream habitats in the Newxue River.PDF
  • Effects of exogenous nitrogen enrichment on the distribution of total sulfur in the plant-soil system of the newly created marshes in the Yellow River estuary, China
  • Authors:CHEN Bingbing, SUN Zhigao, SUN Wenguang, WANG Wei, WANG Miaomiao and HU Xingyun
  • Abstract:The Suaeda salsa marsh in the high tidal flat of the northern Yellow River estuary was selected as the study site, and the total sulfur (TS) in the plant-soil system of S. salsa marsh in the newly created marshes in the Yellow River estuary as affected by different N import treatments (N0, no N import treatment; N1, low N import treatment, 9.0 gN m-2 yr-1; N2, middle N import treatment, 12.0 gN m-2 yr-1; and N3, high N import treatment, 18.0 gN m-2 yr-1) was investigated by conducting in situ experiment of N import. Results showed that the TS contents of in different soil layers significantly changed with N import treatments. Except for the surface soil layer, the other soil layers showed an increasing trend with an increase of N import treatments. The TS contents in different organs of S. salsa under different N import treatments generally followed the order:a leaf > stem > root, indicating that leaves were the key tissues for sulfur (S) accumulation. Although different N import treatments did not alter the patterns of S accumulation in different organs of S. salsa or the nutrient supply relationships between aboveground and belowground tissues, the plant could adjust its growth characteristics and nutrient allocations to adapt different nutrient conditions, and the adaptation was particularly evident in plants in the N2 treatment. S stock in plant-soil system increased with the increase in N import, but the increment of soil S stock was considerably lower than that of plant sub-system N supply, indicating that the nutrient supply between N and S was inconsistent. Our findings revealed that the increase of N loading in the newly created marshes of the Yellow River estuary not only accelerated the S biological cycling rate in the plant-soil system of S. salsa marshes, but also formed a mechanism of positive feedback between N and S, which might favor the maintenance and health of the newly created marshes.
  • DownLoad:Effects of exogenous nitrogen enrichment on the distribution of total sulfur in the plant-soil system of the newly created marshes in the Yellow River estuary, China.PDF
  • Prioritization of wetland restoration in Sanjiang Plain, based on historical biodiversity and landscape structure
  • Authors:QU Yi, LUO Chunyu, ZHANG Hongqiang, ZENG Xingyu, CUI Ling, LI Haiyan and NI Hongwei
  • Abstract:Sanjiang plain is the largest distribution area of fresh water swamp in China. The large-scale agricultural activities resulted in a sharp decrease in wetland area, which led to degradation of wetland ecosystem services and a series of ecological and environmental problems. Wetland restoration is urgently needed. The historical biodiversity distribution and landscape structure of wetlands have an important guiding significance for wetland restoration. Based on the analysis of landscape pattern changes of wetlands, we combined conservation value of historical biodiversity (representing restoration value) and landscape structure of wetland (area proportion) to prioritize the wetland restoration efforts. Our results showed that during 1995 and 2015, the total area of Sanjiang plain wetland was reduced from 14308.55 km2 to 8532.29 km2, and approximately 40% of the original wetland had been degraded into grassland or converted to farmland. Meanwhile, the number of patches has doubled, with the rate of 110.3 patches per year; the patch density increased from 0.15/km2 in 1995 to 0.52/km2; the maximum patch area decreased from 21.20km2 to 14.64 km2. All these figures show that the Sanjiang plain wetlands present overall fragmentation characteristics. The spatial distribution of wetlands in Sanjiang plain is uneven, and the proportion of wetlands in each eastern county is higher, more than 10%; however, the proportion of wetlands in the central and western counties is lower, and the proportion of wetlands in Qitaihe and Youyi county is even less than 5%. Irreplaceability index (IRR) was divided into five grades:0 ≤ IRR ≤ 0.09 (Rank 1), 0.09
  • DownLoad:Prioritization of wetland restoration in Sanjiang Plain, based on historical biodiversity and landscape structure.PDF
  • Spatial distribution patterns of snag and standing trees in a warm temperate deciduous broad-leaved forest in Dongling Mountain, Beijing
  • Authors:MA Fang, WANG Shunzhong, FENG Jinchao and SANG Weiguo
  • Abstract:The warm temperate deciduous broad-leaved secondary forest in Dongling Mountain is relatively well-preserved. Species compositions and community structures are important in the process of secondary forest succession and are also the basis for the next succession. To further study the secondary forest dynamics of biodiversity succession and conservation mechanisms, a relatively large 20 hm2 experimental forest fixed monitoring sample plot in Dongling Mountain was chosen, and the species composition, diameter class structures, and spatial patterns of live standing trees and snags of the warm temperate deciduous broad-leaved secondary forest were analyzed. The results showed that (1) there were 103702 live standing trees with DBH ≥ 1 cm, and a density of 5185.1/hm2 in the plot; there were 4543 snags with a density of 204.9/hm2, both of which included the quantities of branches and sprouted branches. There were 58 species of live standing trees with DBH ≥ 1 cm in the plot, belonging to 33 genera and 18 families; and 33 species of snags with DBH ≥ 1 cm belonging to 23 genera and 15 families; (2) in terms of overall distribution, the diameters of live standing trees and snags fluctuated, showing a trend of first increasing and then decreasing, and the individual abundance of smaller sized trees had significant advantages in distribution; (3) for live standing trees, as the diameter increased, the aggregation intensity decreased, with 10 cm ≤ DBH < 20 cm and DBH ≥ 40 cm, whereas regular, random and aggregate distributions occurred with 20 cm ≤ DBH <40 cm in a scale of 0-50 m. For snags, when DBH < 5 cm and the scale was close to 30 m, a random distribution appeared; moreover, when DBH ≥ 40 cm and the scale was close to 30 m, there was a continuous random distribution, and a clumped distribution occurred when 5 cm ≤ DBH < 40 cm. The spatial distribution patterns showed that sizes of diameters were complementary in spatial structures, and individuals with different diameters occupied different niches in the sample plot; (4) the correlation analysis between different sizes of live standing trees and snags showed that the smaller the diameters and scales, the more obvious relevance, whereas the spatial correlation of large sizes and scales were gradually weakened. Snag production was affected by the density dependence, status and stages of succession of live trees, and habitat heterogeneity; however, the mechanisms involved still need to be studied further.
  • DownLoad:Spatial distribution patterns of snag and standing trees in a warm temperate deciduous broad-leaved forest in Dongling Mountain, Beijing.PDF
  • Study on phytoplankton functional group succession and driving parameters in the Jinhewan Urban Wetland
  • Authors:FAN Xiaochen, DAI Cunfang, LU Xinxin and FAN Yawen
  • Abstract:The Jinhewan Wetland is located in northeastern China, and plays an important role in protecting the biodiversity and regulating the microclimate in Harbin City. Although phytoplankton community studies on wetlands from northern China have increased recently, studies of the phytoplankton community in the Jinhewan Wetland are limited. To better understand processes of phytoplankton community succession in relation to environmental parameters, a detailed survey of phytoplankton functional groups in spring, summer, and autumn are necessary. Therefore, we studied the phytoplankton functional groups and 10 environmental parameters during spring (May), summer (August), and autumn (July). The aim of this study was to understand the succession process of phytoplankton functional groups between seasons, and furthermore explore the dynamic parameters in the Jinhewan Wetland. In this study, phytoplankton were qualitatively and quantitatively collected from 12 sampling sites in four typical habitats. A total of 376 phytoplankton species were identified, belonging to 8 families, 10 classes, 19 orders, 19 families, and 101 genera. The phytoplankton species composition was dominated by Bacillariophyta (39.62%) and Chlorophyta (35.64%), followed by Euglenophyta (10.11%) and Cyanobacteria (9.84%), and the proportions of Pyrrophyta, Cryptophyta, Chrysophyta, and Xanthophyceae were relatively low. Our study showed that the average abundance of phytoplankton in the Jinhewan Wetland was significantly different (P < 0.05). The average abundance in summer was the highest (12.90×106 ind/L), followed by autumn (5.95×106 ind/L), and spring (2.55×106 ind/L). The range of change was 0.97-14.83×106 ind/L, ranging between 0.47-30.17×106, 5.95×106, and 2.55×106 ind/L, respectively. We arranged phytoplankton taxa data from spring, summer, and autumn into 20 functional groups. Groups B/D/F/H1/J/MP/S2/X1 were predominant in spring, groups B/D/H1/Lo/S1/S2/SN/MP/Y were predominant in summer, and groups B/D/F/H1/J/MP/S2/X1 were predominant in autumn. A two-way ANOVA and single-factor cross-similarity test (one-way ANOSIM) showed that there were significant differences in representative functional groups between spring, summer, and autumn (P < 0.05), the representative functional group succession was obvious (P < 0.05), and functional group assemblages were significantly different (P < 0.01). In addition, a SIMPER analysis indicated that the primary contributing phytoplankton functional groups were S2/H1/B/D/Lo/X1/MP in the Jinhewan Wetland. A Canonical Correspondence Analysis (CCA) based on representative functional groups of 10 environmental variables revealed that total nitrogen (TN) was the primary factor affecting the phytoplankton functional group succession in this wetland, and conductivity (SpCond) and pH were closely related to phytoplankton functional group distribution.
  • DownLoad:Study on phytoplankton functional group succession and driving parameters in the Jinhewan Urban Wetland.PDF
  • Response of root morphological characteristics of Quercus liaotungensis seedlings to environmental gradients
  • Authors:DENG Lei, GUAN Jinhong and ZHANG Wenhui
  • Abstract:The objectives of this study were to explore the effects of different environmental conditions on seedling root growth and to provide important guidelines for forest regeneration and sustainable management. Thus, morphological characteristics of seedling roots of Quercus liaotungensis were investigated. The concentrated distribution zone of Q. liaotungensis in Shaanxi Province is located in the Loess Plateau and the north slope of the Qinling Moutains. The study was conducted in three distribution areas of Q. liaotungensis, which including the north slope of the Qinling Moutains (Taibai), southern Loess Plateau (Huanglong), and central Loess Plateau (Yan'an). Root morphological indices of 1-5-year-old Q. liaotungensis seedlings were investigated and the influences of environmental factors on root growth were analyzed. The results showed that root morphological indices were significantly different between trees grown in southern and northern areas. During the early growth stages of the seedlings (1-2 years), root morphological indices were constrained. The total root length, surface area, volume, root tips, averaged diameter, tissue density, and biomass per seedling increased and then decreased from the north slope of the Qinling Moutains to the central Loess Plateau, while the largest indices were documented in Huanglong. As a result, the roots of Q. liaotungensis seedlings in Taibai by improving root forks and decreasing the total surface area, volume, and average diameter to adapted to the environment. The roots of Q. liaotungensis seedlings in Huanglong and Yan'an by improving the elongation, specifically increasing the total surface area, volume, and average diameter, as well as by reducing root forks to adapted to the arid environment. Relationships between seedling root system indices (including the total root length, surface area, volume, root tips, and forks per seedling) and seedling age were best described by a linear function (y=ax + b, a > 0, P < 0.05). Redundancy discriminate analysis revealed that root forks, total root length, specific root length, and root tips of Q. liaotungensis seedlings were significantly positively correlated with available phosphorous, nitrate nitrogen, available potassium, annual precipitation, gravel content, and available nitrogen, whereas they were significantly negatively correlated with soil pH, mean annual temperature, and mean summer temperature. We conclude that appropriate gravel content and moisture are favorable for the growth of Q. liaotungensis seedling roots.
  • DownLoad:Response of root morphological characteristics of Quercus liaotungensis seedlings to environmental gradients.PDF
  • Exploring the effects of vegetation dynamics and climate changes on the Chaohe watershed actual evapotranspiration-Budyko Hypothesis approach
  • Authors:CAO Wenxu, ZHANG Zhiqiang, ZHA Tonggang, WANG Shengping, GUO Junting and XU Hang
  • Abstract:The Budyko hypothesis, less parameters and definite physical significance, was used to quantitatively analyze the effects of climate changes and vegetation dynamics on actual evapotranspiration. It is of great significance to study the water balance and energy distribution in Chaohe watershed. We used the Budyko empirical model to verify the water-energy balance theory based on the hydrological and meteorological data from 1961 to 2015 in Chaohe watershed. The most suitable model of the basin and the optimal values for the model parameters were determined. Furthermore, we quantitatively analyzed the impacts of vegetation dynamics and climate changes on the actual evapotranspiration. Results showed that the Budyko model modified by underlying surface parameters improved the accuracy of predicting actual evapotranspiration compared to the classical Budyko models. The Fu Baopu model had the highest precision in the Chaohe watershed; the mean relative error, the Nash efficiency coefficient, and the coefficient of determination were 27.66 mm, 0.82 and 0.85, respectively. Using the optimizing model parameter (2.54), the Fu Baopu model could better reflect the changed characteristics of the actual evapotranspiration. Finally, the scenario analysis indicated that vegetation dynamics and climate variation in Chaohe watershed played a positive role in actual evapotranspiration; climate changes are a major driver of the increase in actual evapotranspiration.
  • DownLoad:Exploring the effects of vegetation dynamics and climate changes on the Chaohe watershed actual evapotranspiration-Budyko Hypothesis approach.PDF
  • An ecological benefit assessment of the Grain for Green Project in Shaanxi Province
  • Authors:LIU Shengtao, NIU Xiang, WANG Bing, SONG Qingfeng and TAO Yuzhu
  • Abstract:Based on the resource area data of the Grain for Green Project in Shaanxi province by the end of 2013, according to the standards of "Specifications for assessment of forest ecosystem services in China" and "Ecological Standard Monitoring and Evaluation of Grain for Green Project", the ecological benefits of the project in Shaanxi Province were assessed with the distributed measurement method for water storage, soil conservation, nutrient accumulation, C fixation and O2 release, biodiversity conservation, air quality purification, and forest protection. We concluded that the total value of the Grain for Green Project in Shaanxi province was 97.347 billion yuan, with the most valuable assets being water storage (27.407 billion yuan), air quality purification (20.396 billion yuan), and C fixation and O2 release (17.395 billion yuan). The ecosystem service of afforestation on barren hills and wasteland was the highest and the closing hillsides to facilitate afforestation was the lowest. The ecosystem services of ecological forests were better than those of economic forests and shrubs among three forest types. In the value of ecological benefits in different regions, the value of Yan'an city was the highest.
  • DownLoad:An ecological benefit assessment of the Grain for Green Project in Shaanxi Province.PDF
  • Study of multiple vegetation indices reveals photosynthetic phenology in a subtropical evergreen forest
  • Authors:QIAN Zhaohui, WANG Shaoqiang, CHEN Jinghua, ZHOU Guoyi, ZHANG Leiming, LI Yanmu, MENG Ze and CHEN Diecong
  • Abstract:Remote sensing is an effective method to assess terrestrial vegetation photosynthetic physiology and productivity dynamics at a regional scale. The conventional spectral vegetation index such as normalized difference vegetation index does not accurately reveal the photosynthetic phenology of subtropical evergreen forests because canopy structure is relatively stable across seasons. This study calculated the conventional canopy structural vegetation index (normalized difference vegetation index, NDVI), photosynthetic physiological and biochemical vegetation index (chlorophyll/carotenoid index, CCI), and chlorophyll fluorescence vegetation index (normalized difference fluorescence indices, NDFI) respectively, using the spectral reflection data from the automated multi-angular spectro-radiometer at the Dinghu Mountain Forest Ecosystem Research Station in Guangdong, China. We compared and analyzed their differences in tracking gross primary productivity (GPP) as measured by eddy covariance at the canopy level. A multivariate linear regression model was built to improve the fitting accuracy of GPP seasonal dynamics in this subtropical evergreen forest. The results show:for this mixed subtropical evergreen forest, 1) GPP was significantly correlated with all three indices, and the correlation with NDVI was the strongest (R2=0.60, P < 0.01); 2) CCI could not replace NDVI as a better vegetation index to reveal GPP seasonal dynamics (R2=0.55, P < 0.01); 3) NDFI could be used as a secondary index to effectively improve assessment of photosynthetic phenology (R2=0.68,P < 0.001).
  • DownLoad:Study of multiple vegetation indices reveals photosynthetic phenology in a subtropical evergreen forest.PDF
  • Effects of heat storage on surface energy balance in Caragana forest land of northern the Loess Plateau
  • Authors:SUN Shuchen and SHAO Ming'an
  • Abstract:Surface-energy balance has become a major and difficult problem in the study of surface land processes. The arbitrary neglect of terms for heat-storage flux is one of the main causes preventing closure of the energy balance during measurements or calculations. We analyzed the characteristics of the mean seasonal and daily variations of heat storage, and the influence of heat-storage flux on energy-balance closure, using eddy-covariance data for a Caragana stand in the wind-water erosion crisscross region of the northern the Loess Plateau collected from August to October 2014 and April to June 2015. All terms for heat-storage flux of the Caragana stand varied considerably both seasonally and diurnally. The energy-balance closure increased at an average of 11.91% when the terms for heat-storage fluxes were included. The soil heat flux was the largest contributor to the energy closure, accounting for 95.63% of the total heat-storage fluxes. The sum of the photosynthetic and atmospheric heat-storage fluxes accounted for less than 5% of the total fluxes, and photosynthesis contributed more than the atmosphere to perceptible heat storage. The latent heat-storage flux, however, decreased the energy-balance closure by 0.06%, indicating that the heat-storage flux should not be neglected when analyzing energy balances for the Caragana stands of the northern the Loess Plateau. The heat-storage fluxes in the Caragana stand were influenced by solar radiation, air temperature, and soil temperature and soil moisture. The growing condition of the vegetation was another important factor that influenced the seasonal and diurnal variation of the terms for heat-storage flux, and which also affected energy closure.
  • DownLoad:Effects of heat storage on surface energy balance in Caragana forest land of northern the Loess Plateau.PDF
  • Effects of potassium sources and rates on crop yields and microbial community structure in a four-year experiment in purple soil
  • Authors:HUANG Xuejiao, WANG Fei, GU Shoukuan, YUAN Ting, JIN Kexu, FAN Chi, LI Zhenlun and WANG Zhengyin
  • Abstract:Community structures and edaphon quantities play important roles in soil quality changes and nutrition cycling. Different fertilization patterns strongly affect community structure and edaphon quantity, as well as plant and cultivated land quality. However, there is little information about the soil microbial community and functional diversity that is affected by different potassium fertilizer sources on purple soil. To understand the effects of potassium sources and rates on crop yield and microbial community structure in the Chongqing region, a four-year (12 seasons) experiment was conducted on a purple vegetable soil with a rotation of lettuce-cabbage-sweet corn. There were seven treatments consisting of a control (CK, no potassium fertilizer), low dose of chemical potassium fertilizer (K1), medium dose of chemical potassium fertilizer (K2), high dose of chemical potassium fertilizer (K3), low dose of straw (M1), medium dose of straw (M2), and K1+M1. Crop yields, soil microbial properties including contents and composition of microbial phospholipid fatty acids (PLFA), the microbial community, and the ratios of microorganisms were investigated. Results showed that application of two types of K fertilizer sources increased the yield of lettuce, cabbage, and sweet corn when applied at 300 kg·N hm-2 and 150 kg·P2O5 hm-2. The treatments of K2, M2, and K1+M1 effectively promoted cabbage yield by 28.05%-30.27%. The treatments of M2 and K1+M1 effectively increased lettuce yield by 13.89% and 13.81%, respectively, whereas the K1+M1 treatment effectively enhanced sweet corn yield by 15.10%. These results elucidated that the K1+M1 treatment appeared to be an effective combination for production of these three crops. The PLFA analysis of soil microbes showed that different potassium sources affected the soil microbial community structure and abundance. The K1+M1 treatment improved the content of bacteria, fungi, and gram-positive bacteria, and thus significantly increased the total PLFA content and mitigate environmental stress imposed on microbial survival. It further illustrated that the application of corn straw with a small amount of chemical potassium fertilizer (K1+M1) could create a favorable environment for the growth and reproduction of soil microbes. Correlation between the average yield of three crops (lettuce, cabbage, sweet corn) and the content of soil microbes (bacteria, fungi, gram-positive bacteria, and gram-negative bacteria) was significant (P < 0.05), whereas different K sources and rates affected soil microbial characteristics. Thus, K fertilizer might increase crop yield by regulating soil microbial characteristics.
  • DownLoad:Effects of potassium sources and rates on crop yields and microbial community structure in a four-year experiment in purple soil.PDF
  • Morphological variation in flowers of wild populations of Chimonanthus praecox in Zhejiang Province and its correlation with environment factors
  • Authors:DU Huicong, JIANG Yating, TIAN Min, ZHANG Ying and WANG Caixia
  • Abstract:To determine the morphological variation in flowers and its correlation with environment factors and morphological diversity among or within populations, five natural populations of Chimonanthus praecox in Zhejiang Province were chosen as research subjects. We investigated 16 floral phenotypic traits and used nested analysis, principal component analysis, correlation analysis, and un-weighted pair group method with arithmetic averages (UPGMA) cluster analysis to analyze the experimental results. The results showed that there were extremely significant differences among most of the floral characteristics of Chimonanthus praecox. The average variation coefficient of ovule number was highest, and the average variation coefficient of corolla inner diameter was smallest. The corolla inner diameter was the most stable phenotypic trait. The mean coefficient of variation (CV) of all traits was 15.03% with the range from 10.81% to 23.38%, and the average phenotypic differentiation coefficient (Vst) was 44.38% with the range from 1.57% (pistil number) to 89.62% (corolla diameter), phenotypic variation within a population was 55.62%. Average value of CV of the Wujianshan population was the largest and that of the Longwangkan population was the smallest. The variation within populations was greater than that among populations, which indicated that the former was the main source of the floral morphological variation. The principle component analysis showed that corolla diameter, corolla inner diameter, flower cylinder depth, and middle perianth length contributed the most variation. Correlation analysis showed that there were significant and highly significant correlations between parts of floral traits. The soil acidity appeared to be the most prominent ecological factor influencing phenotypic traits of flowers. The results of the analysis on the correlation between floral morphological characters and environment factors indicated that none of the studied environment factors played a significant leading role to affect the variation of one single character. Different environment factors could have different influences on variation of a single character, whereas the same environmental factor showed somewhat different effects on different characters. Macroelements had greater correlation with floral traits than did microelements and mid-elements. According to UPGMA cluster analysis, five populations could be classified into two groups. The UPGMA cluster analysis showed that the morphological variation of the five natural populations of Chimonanthus praecox were not fully clustered in accordance with the geographical distance. It is suggested that there is rich variation and diversity of floral traits among wild Chimonanthus praecox populations, corolla diameter, the length of the middle perianth, and the ratio of length to width of the middle perianth had significant positive correlations with the content of copper, the ovule number had a significant positive correlation with the content of calcium, the ratio of length to width of the middle perianth had a significant positive correlation with the content of iron, and the number of inner perianth had a highly significant positive correlation with altitude of the habitat.
  • DownLoad:Morphological variation in flowers of wild populations of Chimonanthus praecox in Zhejiang Province and its correlation with environment factors.PDF
  • Plasticity of root morphology of Ziziphus jujuba var. spinosa in response to natural drought gradient ecotopes
  • Authors:ZHU Guanglong, CHEN Xubing, GUO Xiaoqian, JIAO Xiurong and ZHOU Guisheng
  • Abstract:Water and nutrition are mainly uptaken by the root system, and the root system is directly grown in the soil and is sensitive to stress. In arid environments, the structure of the root system could be changed to maintain normal biology function and adapt to stress conditions. To date, most of the studies have focused on the structure or morphology of root system responses to single stress factors. However, less attention has been concentrated on the adaptive mechanism of the entire root structure to different ecotopes. Therefore, this study explored the root morphological plasticity of Ziziphus jujuba var. spinosa in response to natural drought gradient ecotopes. Root samples were selected from Yantai-Shijiazhuang-Yinchuan-Turpan of China. The four ecotopes formed a natural drought gradient environment according to their soil moisture, annual precipitation, and humidity coefficients. The purpose of this study was to elucidate the mechanism of root plasticity response to different environments caused by climate change. The results showed that root primary structure of Ziziphus jujuba var. spinosa included the epidermis, cortex, and vascular cylinder. The epidermis is on the surface of the young root, which is constituted by a single layer of epidermis cells that are small and arranged closely. The cortex takes the greatest proportion of the primary structure, and it is constituted by a larger quantity of parenchymal cells. The vascular cylinder is located in the innermost layer, and the cells are small and crowded together. It is composed of pericycle, primary xylem, primary phloem, and parenchymal cells. When drought aggravated, the thickness and width of the epidermis cells were increased. In addition, the thickness, width, and number of plies of parenchymal cells, and the thickness of the cortex were all largest at the Yinchuan ecotope. The root secondary structure of Ziziphus jujuba var. spinosa was divided into periderm (phellem layer, phellogen, phelloderm) and secondary vascular tissue (secondary phloem, vascular cambium, secondary xylem). As the drought intensified from Yantai to Turpan, the thickness and density of periderm was gradually increased. In addition, the diameter and quantity of vessels in secondary xylem were increased. These results illustrated that one of the adaptive mechanisms of plant to drought stress is the changes in the plasticity of root structure that enhance water uptake capacity and water transport efficiency. On the other hand, it improves water retaining capacity and decreases water desorption.
  • DownLoad:Plasticity of root morphology of Ziziphus jujuba var. spinosa in response to natural drought gradient ecotopes.PDF
  • The response of the relationship between transpiration rate and leaf traits of Atriplex patens to population density in the national wetland park conservation areas in Qinwangchuan
  • Authors:REN Yue, ZHAO Chengzhang, LI Xueping, ZHANG Jing and LEI Lei
  • Abstract:The environmental response of plant relationships between transpiration rate and leaf traits is of vital significance to explore the ecophysiological mechanism of the coupling of plant carbohydrate metabolism and building modes for leaf traits. The objective of this study was to examine the relationship between atriplex (Atriplex patens) transpiration rate and vein density and midrib diameter under the influence of different population densities. The study site was located in the national wetland park conservation areas in Qinwangchuan, Gansu Province, China (36°27'59.6″ N,103°39'5.6″ E). The study area was on a platform at the center of the wetland, gently transiting through the wetland community, in which atriplex was the single dominant species. The sample area was divided into 3 levels based on plant density, high (I, 16-21 plant/m2), medium (Ⅱ, 9-15 plant/m2) and low (Ⅲ, < 9 plant/m2), In order from bottom to top, six (2 m×2 m) atriplex samples were selected per plot, numbering 24 samples (4×6) in all. Then, community traits (height and coverage) and soil moisture were determined and 6 individuals of Atriplex patens were taken to the laboratory to measure the leaf thickness, leaf area, vein density, and midrib diameter. In addition, the leaf net photosynthetic rate (Pn), transpiration rate (Tr) and other parameters of the atriplex were measured in each plot. Quadrat survey methods were used to determine the relationship between transpiration rate and leaf traits of the atriplex. The results show that when the soil population density was decreased, the wetland vegetation community height and coverage presented increasing-decreasing changing trends; vein density (VD) and leaf transpiration rate (Tr) presented increasing trends, and the midrib diameter (MD) displayed a decreasing trend. There was a highly significant positive correlation (P < 0.01) between Tr and VD, and there was a significant negative correlation (P < 0.05) between Tr and MD at plot (I, Ⅲ), whereas the correlation was not significant (P > 0.05) at plot (Ⅱ). In the high-density sample plot (I), atriplex preferred a low vein density and a large midrib diameter to realize the low transpiration rate; in the low density sample plot (Ⅲ), atriplex preferred a large vein density and a small midrib diameter to achievea a higher transpiration rate; in the medium density sample plot (Ⅱ), atriplex chose an investment strategy of balanced vein density and midrib diameter to achieve a higher transpiration rate. These results reflect the phenotypic plasticity mechanism of plant populations as they adapt to heterogeneous habitats.
  • DownLoad:The response of the relationship between transpiration rate and leaf traits of Atriplex patens to population density in the national wetland park conservation areas in Qinwangchuan.PDF
  • Patterns of ecoenzymatic stoichiometry on types of forest soils form different parent materials in subtropical areas
  • Authors:ZHANG Xingxing, YANG Liuming, CHEN Zhong, LI Yiqing, LIN Yanyu, ZHENG Xianzhi, CHU Haiyan and YANG Yusheng
  • Abstract:The stoichiometry of ecoenzymatic activity can be used as an important indicator to measure the energy of soil microbes and soil nutrient resource constraints, and is one of the hotspot issues in the field of ecology. However, the role and mechanism of soil parent material and forest types in regulating the stoichiometry of ecoenzymatic activity is uncertain. In this study, we investigated the variations in soil properties, microbial biomass carbon, nitrogen, phosphorus, and soil enzyme activity in the soils of a Castanopsis carlesii and Cunninghamia lanceolata forest developed from two kinds of parent materials (sandstone and granite). These study sites were expected to reveal the patterns of ecoenzymatic stoichiometry on two types of forest soils developed from different parent materials in subtropical areas. The results showed that soil acid phosphatase activity (AP) was significantly higher in granite plots than in sandstone plots, and the values of βG:AP and NAG:AP in granite plots were significant lower than that of sandstone plots. In granite plots, the values of βG:AP and NAG:AP were significantly higher in Castanopsis carlesii forest than Cunninghamia lanceolata forest, and in sandstone the values of βG:AP and NAG:AP were significant higher in Cunninghamia lanceolata forest than Castanopsis carlesii forest. In addition, the correlation analysis suggested that soil enzyme activity and the stoichiometry of ecoenzymatic activity were controlled by soil abiotic factors and biotic factors, and redundancy analysis (RDA) showed that soil pH, total phosphorus (TP), and microbial biomass carbon (MBC) accounted for the variation in soil enzyme activity and ecoenzymatic stoichiometry by 56.9%, 27.9%, and 12.3%, respectively. In summary, the ecoenzymatic stoichiometry could reflect the limitation of phosphorus in different forests, and they were more serious in granite than in sandstone. Thus, we suggested that the soil parent material and forest type should be considered as the important factors in forest management in the future.
  • DownLoad:Patterns of ecoenzymatic stoichiometry on types of forest soils form different parent materials in subtropical areas.PDF
  • Soil microbial functional diversity patterns and drivers along an elevation gradient on Qinghai-Tibet, China
  • Authors:WANG Ying, ZONG Ning, HE Nianpeng, ZHANG Jinjing, TIAN Jing and LI Liangtao
  • Abstract:Microbial diversity plays critical roles in regulating multiple ecosystem functions and enhancing ecosystem stability. In this study, we investigated the functional diversity of the microbial community and its driving factors at six different elevations in Tibet by using Biolog microplate analysis. The results showed that:(1) The carbon utilization of the soil microbial community at different elevations of the alpine meadow increased gradually with culturing time. As elevation increased, microbial metabolic activity and the community diversity index all exhibited unimodal trends in the order of 4800 m > 4950 m > 4400 m > 4650 m > 5100 m > 5300 m. (2) The principal component analysis showed that the elevation gradient significantly influenced the metabolism diversity of microbial community. Polymer, carboxylic acids, and amino acids were the preferred carbon sources for the soil microorganisms. The utilization of carbohydrates, carboxylic acids, and amino acids was more sensitive than that of other carbon sources to changes in elevation. (3) The variation partitioning analysis showed that the soil, plant, and climate were the most important factors for explaining the carbon metabolism of the microbial community diversity and explained 79% of the variation. The partial mental test showed that the soil moisture, vegetation richness, and average annual precipitation were the most important environmental factors that influenced the variations in the utilization of microbial carbon sources at different elevations. In conclusion, our study showed that the metabolic diversity of soil microbial carbon sources was clearly varied with elevation, and soil water content, vegetation richness, and mean annual precipitation were the main factors underlying this variation.
  • DownLoad:Soil microbial functional diversity patterns and drivers along an elevation gradient on Qinghai-Tibet, China.PDF
  • Soil microbial community structure of Pinus massoniana forest under various forest management practices
  • Authors:LEI Lei, XIAO Wenfa, ZENG Lixiong, HUANG Zhilin, GAO Shangkun, ZHANG Weicheng and WANG Song
  • Abstract:Soil microorganisms can make up more than 95% of the total soil biomass, and plays important role in decomposition of carbon sources and organic matter. Forest management practices (e.g., harvesting, burning, and thinning) influence the composition of the soil microbial community by affecting habitat and substrate for soil microorganisms directly and indirectly, and hence affect soil carbon process. Quantifying the responses of the soil microbial community to forest management is vital to accurately evaluate forest carbon balance and to reveal the underlying mechanisms of soil carbon process change. Thus, an aerially seeded Pinus massoniana forest was chosen in the Three Gorges reservoir area to evaluate the effects on soil microbial community owing to different forest management practices (i.e., control; shrub-removal:harvesting all shrubs and removing all harvest residues. Harvest strategy 1:15% harvest intensity and removing main harvest residues without leaves and small branches; Harvest strategy 2:70% harvest intensity and the same harvest residue management as that in harvest 1). All experimental treatments were located in similar habitats and consisted of three 20 m×20 m plots. The treatments were conducted in October 2013, and soil samples were collected in December 2013 (2 months post treatments) and December 2014 (12 months post treatments) to analyze soil microbial community by using phospholipid fatty acid (PLFA) methods, and analyze soil chemical properties. The results showed that the total microbial biomass and biomass of all microbial species (except arbuscular mycorrhizal fungi) in shrub-removal, harvest strategy 1 and harvest strategy 2 were lower than those of the control in December 2014. However, there was no consistent rule observed in December 2013. Principal component analysis indicated that all treatments showed no significant change in soil microbial community structure in December 2013; the 2 principal component factors related to microbial community diversity explained 60.90% and 17.40% of the variation respectively. Shrub-removal, harvest strategy 1 and harvest strategy 2 did significantly affect soil microbial community structure in December 2014, and the 2 principal component factors related to microbial community diversity explained 50.40% and 26.70% of the variation respectively. In 2013, 5 PLFAs (Mel 16:0, 16:1w5c, 16:1w7c, al17:0 and 20:1w9c) played a major role in the first principal component, and 7 PLFAs (Mel16:0, 16:1w5c, 14:0, 16:0, cy17:0, 16:1w7c, i14:0) played a major role in the first principal component in 2014. The fungi (20:1w9c) PLFAs played the most significant role in the first principal component in 2013 and was replaced by gram negative bacteria (16:1w7c) PLFAs in 2014. Soil moisture, ratio of soil temperature and soil moisture, and soil microbial quotient (ratio of soil microbial biomass carbon and soil organic carbon) were significant factors regulating soil microbial community structure at different treatment times (P < 0.05), as revealed by redundancy analysis (RDA).
  • DownLoad:Soil microbial community structure of Pinus massoniana forest under various forest management practices.PDF
  • Bacterial structure and diversity of four plantations in the Yellow River Delta by high-throughput sequencing
  • Authors:DING Xinjing
  • Abstract:The Yellow River Delta, one of the three major pedogenic river deltas in China, is the fastest forming delta with important reserved land resources. To improve the environments of the Yellow River Delta, many plantations have been established since 1950s. Building plantations has been a main trend in the Yellow River Delta for it can not only adjust the temperature and relative humidity of woodlands, but also improve soil fertility. Soil provides nutrients for aboveground vegetation as well as microorganisms in soil. Soil bacteria, one of the key groups of soil microorganisms, play an important role in promoting organic matter decomposition, accelerating mineral and nutrient cycling, maintaining and improving soil fertility. By analyzing the relationship between the soil bacterial community and soil characteristics of plantations, We can understand bacteria in soil better and develop a method to improve plantations. High-throughput sequencing technology, a new method with more advantages over traditional methods to retrieves classification information of soil bacteria more conveniently and accurately, has been widely used in studying soil bacterial community now. The aim of this research was to investigate structure and diversity of the soil bacterial community at four plantations in the Yellow River Delta. Using high-throughput sequencing technology, we compared the soil bacterial structure and diversity of Robinia pseudoacacia, Ulmus pumila, Fraxinus velutina, and Ailanthus altissima plantations and analysed bacterial community correlation with its soil properties. The results showed that the bacterial community in soil of the four plantations consisted of 36 phyla. Acidobacteria, Proteobacteria, and Actinobacteria were the abundant bacterial taxa in soil of four plantations and Nitrospirae in soil of Robinia pseudoacacia and Ailanthus altissimais plantation, with their relative abundance more than 10%. There were significant differences of the relative abundance of Acidobacteria, Proteobacteria, Nitrospirae, Gemmatimonadetes, Bacteroidetes, Euryarchaeota, Crenarchaeota, Cyanobacteria in the soil among different plantations. The bacterial diversity of the Robinia pseudoacacia plantation was the highest among the four plantations sampled, with species, Chao1 index, and Shannon index being 1769.55, 2526.61, and 8.75 respectively. The bacterial diversity of the Fraxinus velutina plantation was the lowest among the four plantations, with species, Chao1 index, Shannon index being 1571.47, 1824.20, and 8.35 respectively. Water content, available K, available N, organic matter content of the Ailanthus altissima plantation and available P content of the Robinia pseudoacacia plantation were the highest among the four plantations. Available P, available K, available N, organic matter content of the Ulmus pumila plantation were the lowest. Correlation analysis showed that there was a significant negative correlation between pH, water content, organic matte content, and relative abundance of Acidobacteria, and a positive correlation between pH and relative abundance of Proteobacteria, Nitrospirae, Gemmatimonadetes. There was a significant positive correlation between pH, available P content, and bacterial diversity. The analysis of bacterial 16S rRNA showed a certain extent of differences in soil bacterial community structure and diversity of four plantations in the Yellow River Delta. Soil pH, water content, organic matter content, and available P content were the main soil factors affecting the soil bacterial structure and diversity. Further research also is needed to obtain more information about soil microorganisms.
  • DownLoad:Bacterial structure and diversity of four plantations in the Yellow River Delta by high-throughput sequencing.PDF
  • Substrate compositions facilitate clay restoration of the simulation study in an opencast coal mine in the eastern steppe of China
  • Authors:WANG Zhigang, BI Yinli, SONG Ziheng, ZHANG Jian, CAI Yun, GONG Yunli and HU Jingjing
  • Abstract:A pot experiment was conducted to study the differences between clovers (Trifolium repens Linn) in biomass, nutrient uptake, physical, chemical, and biological properties of substrates among various mixtures with clay, topsoil, or sandy soil, in order to obtain the optimal mixture ratio. The results showed that the substrates with different mixture proportions significantly influenced clover productivity; the biomass varied with the type of substrate and was in the range of 26.5-40.0 g/pot (average=31.2 g/pot) for the clay and topsoil combinations and in the range of 14.9-20.3 g/pot (average=18.9 g/pot) for the clay and sandy soil combinations; the biomass was 9.0 g/pot, 5.4 g/pot, and 41.7 g/pot for the clay, sandy soil, and topsoil, respectively. Similarly, the highest N acquisition was 1071 mg/pot of clover in the clay and topsoil combinations, which was 1.62, 3.34, and 5.64 times higher for the clay and sandy soil combination, clay, and sandy soils, as were P and K acquisition, which was significantly altered by the difference in root diameter, root length, root surface area, and tip numbers. In comparison with the clay and sandy soil, the soil bulk density and maximum moisture holding capacity were significantly decreased by 7.4%-21.5% and 24.5%-71.8%, respectively, whereas the infiltration rate, porosity, normalized mean weight diameter, total N, organic matter, Olsen P, available K, electric conductivity of the clay with topsoil and clay with sandy soil combination were markedly enhanced by 26.9%-96.3%,45%-218%, 34%-72%, 23.0%-88.3%, 25.1%-146%, 44.0%-91.5%, 70.3%-114.8%, and 3.5%-59.3%; the activities of phosphatase, urease, nitrate reductase, invertase, and nitrogenase were significantly increased by 45.5%-105%, 65.2%-172.3%, 160%-252%, 53.4%-62.7%, 197%-374%; the numbers of fungi, bacteria, and actinomycetes were also increased by 119%-142%, 93.5%-107%, and 83%-147%, respectively. Significant positive correlations were observed between clover productivity and soil physicochemical or biological properties via correlation analysis; overall, the effect of substrates occurred in the order clay+topsoil=topsoil > clay+sandy soil > clay > sandy soil. Thus, the clay and topsoil or sandy soil mixtures provided significantly enhanced substrate conditions; in particular, the 1:2 clay and topsoil ratio was the optimum choice in the opencast coal mine in the eastern steppe of China.
  • DownLoad:Substrate compositions facilitate clay restoration of the simulation study in an opencast coal mine in the eastern steppe of China.PDF
  • The influence of hydrodynamic characteristics on the infiltration process of soil water in a coal mine reclamation area
  • Authors:YANG Yonggang, SU Shuai and JIAO Wentao
  • Abstract:Soil water plays an important role in plant growth, solute transport, and soil environment changes. It is a key scientific problem to reveal the infiltration process of soil water in the unsaturated zone. This study used a typical mining area as the study area to investigate the unsaturated hydraulic conductivity, soil bulk density, porosity, and particle size in the different depths of soil layer by conducting a dye tracer experiment. This study aimed to elucidate the infiltration process of soil water and distribution characteristics in the unsaturated zone. The results showed that, at the experimental infiltration water of 30, 60, and 90 L, the greatest diffusion distance are 10, 30, and 35 cm, respectively, along the X direction and 10, 25, and 30 cm, respectively, along the Y direction. Soil water infiltration showed obvious heterogeneity and spatial variability. With more amount of water, it infiltration deeper and diffusion wider, and this was noted in a declining trend. When suction was greater than 300 hpa, the content of soil particle size between 0.01 and 0.05 mm was negatively correlated with unsaturated hydraulic conductivity. Unsaturated hydraulic conductivity decreased nonlinearly with increase in suction, suction and unsaturated hydraulic conductivity fitting with the exponential function (r2 > 0.9), and regression analysis was performed for the parameters a, b, and soil bulk density (x) as follows:a=0.0015x2 - 0.00499x + 0.0004, b=0.0583x2 + 0.1234x - 0.0726. Under the same suction, bulk density of soil was greater, whereas unsaturated hydraulic conductivity was smaller. when the suction value is 300 hpa, the unsaturated hydraulic conductivity reaches a peak value. Unsaturated hydraulic conductivity was negatively correlated with bulk density, whereas positively correlated with total porosity, and the correlation rate decreased with increasing suction.
  • DownLoad:The influence of hydrodynamic characteristics on the infiltration process of soil water in a coal mine reclamation area.PDF
  • The impact of urban expansion on net primary productivity in the Taihu Lake basin based on nighttime light images
  • Authors:QIAO Xuning, GU Yangyang, ZOU Changxin, HUANG Xianfeng and HU Tao
  • Abstract:Understanding the relationship between human activities and ecological environment and identifying the changing areas of the ecological environment and their causes is of great significance to the formation of ecological protection policies for differentiated regions. The Taihu Lake basin is the core of the Yangtze River Delta, which has experienced rapid economic growth (GDP +15.7%/year), population growth (+3.0%/year on average), urbanization (+ 9.2%/year on average) from 1985 to 2010. Rapid industrialization and urbanization have significantly changed the pattern of land use, which has posed a threat to the region's ecological security and sustainable development. Based on the MODIS 17A3 and DMSP/OLS nighttime light images, we determined the urban development level index, and a linear trend analysis was used to partition the urban development levels. We used the Pearson correlation coefficient to calculate the relationship between the urban development level and net primary productivity (NPP). Finally, a spatial correlation model was used to analyze the impact of urban expansion on the NPP in the Taihu Lake basin, combined with geographic information system (GIS) and remote sensing (RS) techniques. The results showed that the average NPP in the Taihu Lake basin varied from 388.79 gC m-2·a-1 to 452.54 gC m-2·a-1 from 2000 to 2010. The average NPP over 11 years was 422.65 gC m-2·a-1. The changes in average annual NPP were fluctuating and declining. The urban development level slow-increased zone had little effect on the change in NPP, while the increased zone and rapid-increased zone had great influence on the NPP. Along with the increase in the urban development level, land transformation mainly occurred from farmland to construction, forest to construction, and water to construction. The rapid expansion of urban areas has led to increase in construction land and the urban development level, which are the main reasons for the decrease in NPP.
  • DownLoad:The impact of urban expansion on net primary productivity in the Taihu Lake basin based on nighttime light images.PDF
  • Sustainable development of tourism in a vulnerable ecological region: an emergy analysis of the Gannan Tibetan Autonomous Prefecture
  • Authors:LI Wei, HAN Peijie and ZHAO Xueyan
  • Abstract:The sustainable development of tourism has significant importance on the natural complex ecosystems and lives of humans and now become a global demand. The contradiction between eco-environmental protection and tourism development in vulnerable ecological regions is particularly salient. It is urgent to evaluate the development sustainability of tourism in such areas, which could promote the coordinated development of tourism economy and ecological protection. Taking Gannan Tibetan Autonomous Prefecture as the research area, this paper incorporates an emergy analysis and applies indexes such as Eti(tourism emergy income), Ete(tourism energy export), TELR(tourism environment load ratio), TEER(tourism emergy exchange ratio), and TSEI(tourism sustainable emergy index) to evaluate the development sustainability of tourism in Gannan from 2006 to 2015. This research results were concluded based on the survey data, the statistical data and the data from the emergy transformation. This research attempts to enhance the quantitative study on the sustainable development of tourism and provide a scientific underpinning for the comprehensive evaluation and sustainable management of vulnerable ecological regions. The findings are as follows:(1) from 2006-2015, the emergy value increased in tourism input and output per year in Gannan. Emergy for rigid demands, such as the demands for catering services and accommodations, accounted for 59%-82% of the total output emergy. This constitutive structure was unfavorable to sustainable development. (2) During this period the sustainability of the researched area was unstable. From 2006-2008, the TSEI declined from 2.49-0.94. A large consumption of nonrenewable resources caused great pressure on the environment, rendering the tourism development in this area unsustainable. From 2008-2015, the TSEI rose to7.85, and the tourism development in this area was changed to a sustainable pattern. However, from 2014-2015, the effective emergy output efficiency was still low, which indicated poor sustainability of tourism system in Gannan.
  • DownLoad:Sustainable development of tourism in a vulnerable ecological region: an emergy analysis of the Gannan Tibetan Autonomous Prefecture.PDF
  • Optimization of land use in Zhangjiajie City under tourism ecological security constraints
  • Authors:ZHU Dongguo, XIONG Peng and FANG Shimin
  • Abstract:Optimization of land use usually focuses on quality structure as it considers the maximization of economic, social, and ecological benefits as the goal. However, space structure optimization of land use under tourism ecological security constraints is hardly done. On account of this situation, only if the optimization of quality structure as well as space structure is taken into practice under the constraints can comprehensive land use efficiency and ecological environment improve in tourist cities. A typical tourist city, Zhangjiajie, was used as a case study to construct an tourism ecological safety evaluation index system, and the optimal land use structure under the tourism ecological security constraints based on the Lingo model were determined using the Grey linear programming method; in addition, measures were taken to configure the optimized parameter structure in space according to distribution rules, and finally, to optimize land use space with the help of the CLUE-S model. The results showed that 1) the comprehensive index of tourism ecological security in the year 2015 was 0.7394, indicating a relatively safe state. Specifically, that of the environmental pressure on tourism resources was 0.3231, that of the tourism environment condition was 0.2789, and that of the security degree of the humanistic social response of tourism scores was 0.1374; thus, the tourism environment condition and the security degree of the humanistic social response of tourism are lower than the environmental pressure on tourism resource. 2) Under the optimization of quantity structure, the areas of woodland, water and construction land apparently increased, while the areas of cultivated land, grassland, and unused land decreased. Predictably, the comprehensive index of tourism ecological security in the year of 2025 was 0.8196, which was 0.0802 higher than that in the year 2015, but which also indicated a safe state. Thus, the optimized quantity structure of land use plays a significant role in the ecological security of tourism. 3) Under the optimization of spatial structure, many positive changes have taken place in land use, and they all present more reasonable spatial distribution of land use. Woodland is distributed mainly in mountains and hills in Sangzhi County, Cili County, Wulingyuan District and the southern part of Yongding District; construction land is mainly concentrated in Cili County, Sangzhi County and the urban area of Yongding District; grassland is mainly located in the mountainous areas of Sangzhi County and Cili County as well as Wulingyuan District; cultivated land is distributed mainly in plains and hills of Cili County and Yongding District; utilized land is distributed sporadically in Cili County, Sangzhi County and Yongding District. In conclusion, the results of the study will provide Zhangjiajie City with technical reference points that will facilitate sustainable use of land resources and construction of tourism ecological security.
  • DownLoad:Optimization of land use in Zhangjiajie City under tourism ecological security constraints.PDF
  • Analysis of urban sustainable development level based on POI: a case study in Shaoxing
  • Authors:WANG Tao, ZHANG Nana, LI Huanhuan, ZHANG Yonglin, ZHANG Xueqi and DONG Rencai
  • Abstract:With the arrival of the era of big data, Point of Interest (POI), as an important type of geospatial big data, can reflect aggregation conditions of various elements such as urban population density, urban development level and urban development strength directly. Using the geospatial analysis tool in ArcGIS, the POI data classification information of each district (county, city) in Shaoxing was extracted from one popular POI data source. In order to evaluate the balanced distribution level among districts in Shaoxing, POI data combined with population and area information of each district was analyzed. Furthermore, several analysis methods including kernel density analysis, spatial regression analysis and nearest neighbor analysis were used to dig characteristics of POI's geospatial distribution from different perspectives. Our results indicated that among several districts in Shaoxing, the quantity and the kernel density of POI were larger where there was a higher urbanization level. From the perspective of the number of POI per unit area and per unit population, there appeared an unbalanced development level among several districts. Specifically, the Yue District was most developed, followed by Shangyu District, Keqiao District and Zhuji City, while Xinchang County and Shengzhou City were least developed. The regional discrepancy of infrastructure that provides life and production services didn't accord with the fairness principle of sustainable development. Finally, some suggestions about urban construction and planning in Shaoxing were presented for creating a coordinated, fair and sustainable development among different districts.
  • DownLoad:Analysis of urban sustainable development level based on POI: a case study in Shaoxing.PDF
  • Study on spatial identification of critical ecological space based on GIS:a case study of Poyang Lake Ecological Economic Zone
  • Authors:XIE Hualin, YAO Gan, HE Yafen and ZHANG Daobei
  • Abstract:Ecological space undertakes the mission of maintaining regional ecological balance and provides sustainable ecological space services for society. It is a basic guarantee that regional land ecology can continuously provide society with the benefit of natural space services. In this study, the Poyang Lake Ecological Economic Zone, which is fragile in its natural ecological environment, was used as the research area. Based on relevant practical experience and research results of domestic and foreign scholars, spatial information technology based on RS and GIS was used to evaluate the importance of ecosystem services and the sensitivity of ecosystem; the corresponding evaluation indicators were selected, according to local conditions, to identify the critical ecological space of Poyang Lake Ecological Economic Zone. The results showed that the area of critical ecological space in Poyang Lake Ecological Zone was 27751.25 km2, accounting for 52.55% of the total area of the study area; the urgent ecological space was 17125.31 km2, accounting for 32.43% of the total area; the crisis ecological space was 4431.19 km2, accounting for 8.39% of the total area; and the crucial ecological space was 6194.75 km2, accounting for 11.73% of the total area. In land-use ecological-security conflict analysis, 14.29% of cultivated land and 9.31% of construction land are in a critical ecological zone.
  • DownLoad:Study on spatial identification of critical ecological space based on GIS:a case study of Poyang Lake Ecological Economic Zone.PDF
  • The ecosystem service value spatial-temporal changes in the Ugan-kuqa River Delta Oasis based on RS and GIS
  • Authors:MAYILA Reheman, MAMAT Sawut, NIGELA Taxipulati, YIKILIMAN Abudoumiti, MA Chunyue and YIERXIATI Abulait
  • Abstract:Ecosystem services value (ESV) research is an important way to improve land use patterns and to promote the protection and restoration of regional ecosystems. This study choose the fragile ecological environment of the Ugan-Kuqa River delta oasis as a study area, using remote sensing images in 1994 and 2016 as the basic data to assess the value of ecosystem services. To further investigate dynamic change characteristics of regional ecosystem service values, the grid, sensitivity analysis, spatial autocorrelation, and spatial statistical methods were applied. The results revealed that:(1) 1994-2016 Ugan-Kuqa River delta oasis land use changed, and land cover changed was more significant. Cultivated land and construction land showed an increasing trend, whereas grassland and unused land showed a declining trend. Cultivated land and grassland changed most rapidly. (2) From 1994 to 2016, the total value of ecosystem services in the Ugan-Kuqa River delta oasis decreased from 4895.67×106 yuan to 3864.78×106 yuan, being reduced by 1030.89×106 yuan, an annual reduction of 0.96%; in spaces where the ecological service value added area in the impairment area were in a situation of encirclement. Areas of high ecosystem service value were shrinking. At the same time, the value of ecosystem individual services presented an increasing and decreasing trend. Four single service values, such as waste treatment, water conservation, biodiversity protection, and recreational culture, there was a downward trend. However, food production, climate regulation, gas regulation and raw material, soil formation, and protection, and an additional five individual service values showed an upward trend. (3) The sensitivity analysis revealed that the sensitivity index of ecosystem service value coefficient (CS) of all land use types were less than 1, indicating that the ecological value coefficient (VC) had little influence on the changes of ecosystem service values, the model can reasonably evaluate the fluctuation of regional ecosystem service values. (4) The ecosystem service value of the study area showed obvious spatial autocorrelation and spatial clustering, ecological service value high accumulation areas were mainly distributed in the Ugan-Kuqa River upstream, in the "Kezier reservoir" around and north shore of the Tarim River and showed a decreasing trend. Protection of the spatial stability of the high value area must be considered; the low accumulation area mainly concentrated in the southern part of the oasis was close to the edge of the Taklimakan Desert and near the Tianshan Mountain central area and desert area of the lower reaches of the Kuqa River. The spatial distribution pattern of this kind of area is basically stable. (5) Affected by climate change and human activities, the grassland and water area was greatly reduced and construction land and cultivated land was increased, resulting in the land with higher ecological service value coefficient being continuously reduced, which causes the ecological service value of the study area tend to weaken.
  • DownLoad:The ecosystem service value spatial-temporal changes in the Ugan-kuqa River Delta Oasis based on RS and GIS.PDF
  • Landscapeecological risk assessment of Xi river Basin based on land-use change
  • Authors:LÜ Leting, ZHANG Jie, SUN Caizhi, WANG Xiaorui and ZHENG Defeng
  • Abstract:Land-use change (LUC) affects environmental factors such as soil, atmosphere, and water. Moreover, it threatens regional ecological and environmental health. Landscape pattern is an important indicator that reflects the characteristics of land-use structure, composition and spatial configuration.Landscape changes and their eco-environmental effects have received much attention from researchers and the public. Landscape ecological risk assessment focuses on spatial heterogeneity and the correlations of landscape patterns with ecological processes. The identification of ecological elements and processes in a watershed, particularly within the context of rapid urbanization and environmental change, is of great significance for landscape ecological risk assessment. The Xi River, a tributary of the Taizi River, is located in Liaoning province and runs from south to north through Benxi city. Benxi city is an important heavy industry base in China. It is famous for its metallurgical and mining industries. In recent years, mining has caused many serious environmental problems, which include environmental pollution, mining-induced desertification, and geo-environmental hazards. The landscape pattern of the Xi River Basin has changed significantly because of large-scale mining exploration and deforestation. In this study, remote sensing data, such as those acquired from Landsat TM in 1985, 1995, and 2005, and Landsat OLI in 2015, are used. Land-use types were interpreted, and the dynamic changes in the landscape pattern were analyzed. The whole basin was then divided into 340 ecological risk assessment units. In addition, landscape ecological risks of the Xi River Basin were evaluated using the ERI (Ecological risk index). Geostatistical methods and spatial autocorrelation methods were also used to explore the spatial distribution and accumulation characteristics of landscape ecological risks. The results showed that (1) since 1985, all six types of land use have changed, and the area of construction land has increased the most because of large amount of forest and farmland changing into it. (2) from 1985 to 2015, the regions with highest, higher, and moderate levels of ecological risk have increased and moved from north to south, whereas the regions with the lowest and lower levels of ecological risk have decreased and moved from south to north, thus causing ecological risks for the whole basin to increase; (3) the landscape ecological risks showed positive spatial correlation characteristics, which implied that they were prone to gathering. This study has revealed that the main reason for the temporal and spatial variation of ecological risks in the Xi River Basin is human activity. Land-use changes have the most important effects on ecological risk factors.The assessment of ecological risks in the Xi River Basin can provide a reference for ecological conservation efforts. Managers should determine an optimal combination of the present land-use types with improved reasonable land-use types to improve the land-use structure. We should undertake integrative and rational planning and land-use management aimed at alleviating ecological risks in the Xi River basin, while considering water and environmental pollution, as well as soil erosion problems together.
  • DownLoad:Landscapeecological risk assessment of Xi river Basin based on land-use change.PDF
  • The carbon source function of constructed wetland macrophytes and its improvement strategy
  • Authors:ZHAO Dehua, LÜ Liping, LIU Zhe, ZHANG Miao and AN Shuqing
  • Abstract:Constructed Wetlands (CWs) have been widely used for the advanced treatment of the secondary wastewater from Waste Water Treatment Plant (WWTP). However, the pollutant, especially nitrogen, removal efficiency is greatly limited by the lack of carbon sources in the secondary effluent treatment of CWs because most Biochemical Oxygen Demand (BOD) matter has been removed in WWTP. The main pathway of carbon source supplied from CW macrophytes and its main influencing factors were reviewed in this paper. Furthermore, the universal seasonal dynamics and modes of organic matter supply quantities were established for CW macrophytes in East China. The main objective was to develop a novel strategy to stabilize the carbon-supply function of CW macrophytes for the improvement of pollutant removal efficiency and avoidance of secondary pollution in the decomposition process of macrophyte litter by the configuration of warm-season cold-season macrophyte species. The main pathway of carbon source supplied from CW macrophytes included root exudates, decomposition of under-ground biomass, and the decomposition (and leaching) of above-ground biomass. The CW macrophytes have a relatively high carbon supply for denitrification, which is closely correlated with macrophyte species and numerous environmental factors, and thus varies substantially in both time and space. As an example, Phragmites australis with a maximum above-ground biomass of 5.0 kg/m2 potentially supports a nitrate removal rate of 0.57 kg N/m2 in one year, which is much larger than the values estimated by the previous studies because most previous studies only accounted for the above-ground biomass and ignored other carbon-supply paths of CW macrophytes. Because of the seasonal variation of CW macrophyte carbon-supply function, the universal seasonal models of Biomass Accumulation (BA, the un-decomposed CW macrophyte biomass) and Organic Matter Supplied Quantity (OMSQ, the decomposed CW macrophyte biomass plus the root exudates) were established for representative warm-season and cold-season macrophytes species in East China, respectively. Warm-season and cold-season macrophytes showed significant seasonal complementarity characteristics in both BA and OMSQ. Therefore, the proper configuration of warm-season and cold-season macrophytes in a CW system can greatly stabilize the carbon-supply function of CW macrophytes and thus avoid the secondary pollution by the simultaneous decomposition of most macrophytes litter. The above-ground biomass harvest and return to CW after pretreatment can further improve the artificial management of the carbon-supply function and thus increase the denitrification stimulation function of CW macrophytes. In the future, the related research should be focused on (1) development of the quantitative analysis methodology of OMSQ supplied from CW macrophytes, (2) monitoring the dynamics of the OMSQ quantity and its possible regulation strategies and, (3) design of CW with the ability of supplying stable and high quantity carbon sources from itself as planted macrophytes for improving pollutant efficiency.
  • DownLoad:The carbon source function of constructed wetland macrophytes and its improvement strategy.PDF
  • Review of the evaluation methods of regional eco-environmental vulnerability
  • Authors:ZHANG Xueling, YU Wenbo, CAI Haisheng and GUO Xiaomin
  • Abstract:With the rapid development of world economy and the growth of global population pressure, human activities have been more and more strongly affecting the balance of ecosystem, which increased the vulnerability of environment and aggravated the environmental problems. By reviewing relevant literatures focusing on evaluation the vulnerability of regional eco-environment, it appears that ecological environment vulnerability is a relative concept, affected by multiple interfering factors, such as natural geography, ecosystem restoration ability, and human activities, and that it is the result of the combination of natural and human factors. The paper combined with the study on ecological environment vulnerability including its connotation and characterization and main content of evaluation, evaluation index selection and system construction, evaluation method and analysis model. The paper analyzed the development status in the field of evaluation study on ecological vulnerability, and the difference of index system and evaluation method among different regions of the world. It pointed out the existing problems in many aspects, such as innovation of theoretical methods, construction of evaluation index system and calculation model, quantitative analysis description of the natural factors and human factors evaluation, application of evaluation results. In this paper, the trend of eco-environmental vulnerability evaluation was analyzed based on the evaluation model construction, validity of data processing analysis, and application of evaluation results. To summarize, he research ideas need to be more comprehensive and systematic, the spatiotemporal dynamics have to be highlighted during data processing, the research methods should further highlight the interdisciplinary integration, and the results obtained from these studies need to be more practical and applicable.
  • DownLoad:Review of the evaluation methods of regional eco-environmental vulnerability.PDF

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