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Volume 37,Issue 15
  • Effectiveness of landscape metrics in coupling soil erosion with landscape pattern
  • Authors:LIU Yu
  • Abstract:Landscape pattern analysis by applying landscape metrics is a widely used approach to reveal the ecological consequences of landscape change.Soil erosion is the processes of detachment and relocation of soil materials over landscapes,which are regulated by the spatial pattern of landforms,vegetation cover,and human activities.Therefore,landscape pattern analyses to reveal the effects of landscape pattern shifts,especially the land use/cover change,on soil erosion is a good example of the practice of principles and methodology of landscape ecology.However,the capacity of landscape metrics,specifically metrics of "Fragstats" family,used to explain the relationship between the landscape pattern and soil erosion processes was problematic.Therefore,the establishment of principles to select effective metrics is necessary.In this paper,soil erosion and sediment delivery over multiple years in a loess watershed were modeled using WATEM/SEDEM.Representative landscape metrics from four categories,including patch/edge density,shape indices,metrics describing aggregation,and diversity indices were calculated using Fragstat 4.2 based on land use/cover datasets.The correlation between soil erosion and these landscape metrics were tested to evaluate their validity in coupling landscape pattern shifts with soil erosion dynamics.The consistency in revealing the relationship between soil erosion and the spatial pattern of "sink" and "source" landscape types was also evaluated.The results advocate that there are limitations of applying landscape metrics following the patch-corridor-matrix model to indicate the soil erosion status.However,at the landscape class level,landscape metrics showed greater effectiveness in linking landscape pattern with soil erosion.The following principles for selecting suitable landscape metrics for soil erosion status assessments were determined:(1) the signs of correlation coefficients between soil erosion variables and landscape metrics should be different for sink and source types;(2) the signs of correlation coefficients between landscape metrics for multiple sink or source types and soil erosion variables should be the same.Although landscape metrics are relatively effective in coupling landscape pattern with soil erosion at the class level,we show here that using them as predictive tools could result in considerable uncertainty.It was suggested that development of metrics that reflect the behavior of landscape patterns in soil erosion and sediment delivery could reasonably promote the predictive capacity of landscape metrics.
  • DownLoad:Effectiveness of landscape metrics in coupling soil erosion with landscape pattern.PDF
  • Analysis of spatial and temporal variation of net primary productivity and climate controls in China from 2001 to 2014
  • Authors:LIU Gang, SUN Rui, XIAO Zhiqiang and CUI Tianxiang
  • Abstract:Net primary productivity (NPP) is a key variable in characterizing vegetation activity.NPP also plays an important role in evaluating ecosystem carrying capacity and understanding terrestrial ecosystem carbon cycle.The present study estimated the NPP in China from 2001 to 2014 based on the GLASS remote sensing dataset.We also analyzed the spatial and temporal variation of vegetation NPP in China with linear regression and Empirical Orthogonal Function (EOF) algorithms.By using correlation analysis and Singular Value Decomposition (SVD) method,the relationship between NPP and temperature and the relationship between NPP and precipitation were obtained,respectively.The results showed that (1) NPP in China revealed a decreasing pattern from southeast to northwest due to the spatial variability of vegetation and climatic characteristics.NPP also had a fluctuating increase trend during our study period with values ranging between 3.02 and 3.49 PgC/a.The average value was approximately 3.25 PgC/a.(2) The linear regression and EOF results are consistent.Both results indicated that NPP presented a decreasing tendency in the lower Yangtze region,North China Plain,and Changbai mountain area.In the Qinghai-Tibetan Plateau,northwest,central Inner Mongolia,and southeast coastal areas of China,NPP showed an increasing tendency.(3) The correlation analysis between NPP and meteorological elements indicated that NPP was positively correlated with temperature in the Changbai mountain area,Qinghai-Tibet Plateau,and southern area.NPP was also positively correlated with precipitation in the eastern Inner Mongolia and northwestern region.However,in the Northeast,Yangtze River,and east of the Qinghai-Tibetan Plateau area,NPP was negatively correlated with precipitation.The SVD results were consistent with the results of correlation analysis.We found significant correlations between NPP and temperature and precipitation.NPP was positively correlated with temperature in the Changbai mountain area,Inner Mongolia,and Qinghai-Tibet Plateau area.NPP was also positively correlated with precipitation in the northwest and central Inner Mongolia,whereas it was negatively correlated with precipitation in the lower Yangtze River and northeastern area.
  • DownLoad:Analysis of spatial and temporal variation of net primary productivity and climate controls in China from 2001 to 2014.PDF
  • Provincial forest ecological security evaluation in China based on the entropy weight of the fuzzy matter-element model
  • Authors:LIU Tingting, KONG Yue, WU Ye, ZHU Lingyun and ZHANG Dahong
  • Abstract:Recently,with the rapid development of the economy and society,the decline of forest resources and deterioration of ecological environments have threatened human productivity and lifestyles.In the context of ecological progress,research on the condition of provincial forest ecological security in China has become a fundamental issue,since it plays a vital role in the sustainable development and national economy,affecting the livelihood of people.After analyzing the existing ecological security systems,the pressure-pressure bearing capacity model was proposed.Using software,such as SPSS and EXCEL,the forest ecological security standards of 31 provinces in China were empirically analyzed and evaluated using the principal component analysis,entropy method,and matter-element analysis based on the data from 2014.Results showed that in the pressure evaluation,19 provinces (61.29%) are under high forest ecological security pressure,which means that most provinces face a high ecological security risk,including Hebei,Chongqing,Hubei,Shanxi,and Xinjiang.In contrast,Tibet,Shanghai,Hainan,Gansu and Heilongjiang face lower pressure.Evaluation of pressure-bearing capacity revealed that 12 provinces (38.71%) are under better bearing conditions,which means that the average pressure-bearing capacity of China is relatively low.Fujian,Yunnan,Jiangxi,Hainan and Zhejiang have the highest pressure-bearing capacities,whereas Qinghai,Ningxia,Xinjiang,Gansu and Tianjin have the lowest.In a comprehensive evaluation of forest ecological security,14 provinces (45.16%) showed high forest ecological security,mostly the southern provinces,including Tibet,Hainan,Fujian,Yunnan and Jiangxi,which are in relatively good condition.However,Ningxia,Qinghai,Xinjiang,Hebei and Shanxi indicated low forest ecological security.Therefore,measures such as strengthening the protection of natural forests,exploring alternatives to wood resources,and establishing a forest ecological security early warning system,should be taken.In addition,measures to improve ecological security should be implemented in consideration of the specific needs of each province.
  • DownLoad:Provincial forest ecological security evaluation in China based on the entropy weight of the fuzzy matter-element model.PDF
  • Relationship analysis between specific leaf area and water use efficiency of Phragmites australis in the Zhangye wetland
  • Authors:LI Qun, ZHAO Chengzhang, WANG Jiwei, ZHAO Lianchun, XU Ting and HAN Ling
  • Abstract:Study of the relationship between plant specific leaf area (SLA) and water use efficiency (WUE) under different density conditions is necessary to understand the mechanisms of material circulation and energy flow through the soil,plants,and atmosphere.There were three main goals in this study:(1),to determine the relationship between plant SLA and WUE;(2),to analyze whether the relationship is variant along a gradient;and (3),to explain the causes of the relationship.The study site was located in the national wetland park conservation areas in Zhangye city,Gansu Province,China (100°26'50.72″E,38°58'42.9″N).The study area began at the lakeside and extended to the central section of the lake island,gently transiting through the wetland community,in which the common reed (Phragmites australis) was the single dominant species.The reed community was divided into 3 levels based on density,with a "bundle" forming the sampling unit:Low density (Ⅲ,50-70 bundle/m2),medium density (Ⅱ,130-150 bundle/m2),and high density (I,210-230 bundle/m2).Next,using a zigzag order from bottom to top,six (2 m×2 m) reed samples were selected per density,for an overall total of 18 samples (3×6).Then,community traits (height and density) and soil moisture were determined and 12 individuals of P.australis were taken to the laboratory to measure the leaf thickness.In addition,the leaf net photosynthetic rate (Pn) and transpiration rate (Tr) of the reeds were measured in each plot.Quadrat survey methods were used to determine the relationship between the specific leaf area and water use efficiency of the reeds under three density conditions.The results indicated that,as population density decreased from high,to lower,the wetland community soil moisture content gradually decreased,as well as reed height,leaf area,leaf dry biomass,SLA,and transpiration rate (Tr).However,the net photosynthetic rate (Pn),leaf thickness,and WUE gradually increased.There was a highly significant negative correlation (P < 0.01) between SLA and WUE at high and low densities (I,Ⅲ),whereas it was less significant (P < 0.05) at medium density (Ⅱ).Along the density gradients,the reeds adjusted the shapes of their leaf blades,causing the SLA and WUE to be negatively correlated,which reflected the resource utilization and photosynthetic product accumulation models that the plants adopted to become acclimatized to heterogeneous environmental factors,such as light and soil moisture.
  • DownLoad:Relationship analysis between specific leaf area and water use efficiency of Phragmites australis in the Zhangye wetland.PDF
  • Long-term effects of chemical and organic amendments on red soil enzyme activities
  • Authors:TIAN Shanyi, WANG Mingwei, CHENG Yanhong, CHEN Xiaoyun, LI Daming, HU Feng and LIU Manqiang
  • Abstract:Red soil degradation has become a serious ecological and environmental problem due to irrational utilization.In recent years in particular,with intensive agricultural management targeting higher crop yields,overuse of chemical fertilizers has exacerbated the degradation of red soil.Organic amendment could not only reduce the dosage of chemical fertilizer used but also could improve overall soil quality,including soil physicochemical and microbiological properties that are relevant to soil ecosystem service maintenance and development.Soil enzyme activity is considered to be a valuable soil quality indicator with regard to its relevance to soil functioning and its sensitivity to soil perturbation.Numerous studies have investigated the impacts of fertilization management on soil enzyme activities,mainly focusing on the assessment of enzyme activity responses to different fertilizations however,little attention has been paid to additional information on ecophysiology and ecological stoichiometry associated with multiple enzymatic activities.In the present study,soil samples were collected from a long-term red soil fertilization experiment established in 1986 in the Jiangxi Institute of Red Soil of Jiangxi Province,and were analyzed to investigate the interactive effects of chemical and organic amendment on soil enzyme activity,soil physicochemical properties,and microbial biomass.In particular,the relationship among soil enzyme activity,soil physicochemical properties,and microbial biomass was explored.Four treatments,i.e.,no-fertilizer control (CK),only chemical fertilizer containing nitrogen,phosphorus,and potassium (NPK);only organic amendment (OM);and a combination of organic amendment and chemical fertilizer (NPKM),were selected for use in this study.The results showed that,compared with the CK,long-term fertilization practice (NPK,OM,and NPKM) could promote the activities of soil enzymes involved in carbon cycling (i.e.,α-and β-glucosidase,cellulase and xylanase) and nitrogen cycling (i.e.,leucine aminopeptidase and N-acetyl-β-d-glucosaminidase) to different extents.Among all the treatments,NPKM promoted overall enzyme activity the most,whereas NPK had the least affect.Organic amendment (i.e.,OM and NPKM) decreased the C:N acquisition ratio in comparison with CK,but there was no significant difference between NPK and CK treatments,indicating that organic amendment decreased the proportion of C-acquiring enzymes but increased N-acquiring enzymes.Microbial biomass carbon-specific enzyme activities (MBCE) or soil organic carbon-specific enzyme activities (SOCE) under the OM treatment was significantly lower than in the other three treatments.For example,compared to CK,MBCE was decreased by 56.2% and SOCE by 21.2% in the OM treatment,but these were increased by 7% and 16.9%,respectively,in the NPK treatment.Such results indicate that soil microorganisms obtained relatively more energy in the OM treatment and that the utilization efficiency of organic carbon was higher in this treatment than in the NPK treatment.Similarly,microbial biomass nitrogen-specific enzyme activities (MBNE) increased by 45% in the NPKM treatment compared to that in the CK,but no significant difference was observed between OM and NPK.The results suggest that low C:N acquisition ratio and high MBNE are indicators of N limitation in OM treatment,and organic amendment combined with chemical fertilization could alleviate N limitation.In conclusion,the soil microbial community is mainly limited by C in NPK,whereas it is mainly restricted by N in the OM treatment.Furthermore,NPKM treatment could simultaneously supply organic carbon and nitrogen,satisfying the demands of plant growth and producing a favorable environment for microbial growth.Integrating organic amendment and chemical fertilizer would facilitate sustainable development of soil ecosystem services.
  • DownLoad:Long-term effects of chemical and organic amendments on red soil enzyme activities.PDF
  • Energy balance of an artificial grassland in the Three-River Source Region of the Qinghai-Tibet Plateau
  • Authors:ZHANG Xiang, LIU Xiaoqin, ZHANG Lifeng, NIU Ben, ZHAO Liang and GU Song
  • Abstract:To reveal the influence of planting artificial grassland on the energy balance of the Three-River Source Region on the Qinghai-Tibet Plateau,the variation of the energy budget and its components of an artificial grassland were studied using eddy covariance and micrometeorological methods.The results showed that the highest daily solar radiation (Rs) and net radiation (Rn) were 33.6 and 19.1 MJ m-2 d-1,with annual accumulated values of 6789.4 and 2773.3 MJ m-2,respectively;the radiation efficiency (Rn/Rs) annually averaged 0.41,with a higher value of 0.54 in the growing season from May to September.The sensible heat (H) and latent heat flux (LE) displayed obvious seasonal variations.H was the lowest in December and increased with an increase of Rs,but decreased in the growing season,appearing the sub-low value in mid July.LE remained relatively low in winter,and increased rapidly in early March,reaching a peak in July.The energy partitioning (average annual LE/Rn,H/Rn,and G/Rn were 0.46,0.45,and-0.13,respectively) was mainly composed of LE and H.There were obviously different patterns of seasonal variations of LE and H,with Bowen ratio (β=H/LE) averages for winter,spring,summer,and autumn of 3.33,0.68,0.42,and 1.29,respectively.Affected by the vegetation leaf area index (LAI),the soil water content (SWC) and vapor pressure difference (VPD),and annual maximum values of both the canopy conductance (gc) and decoupling coefficient (Ω) averaged 16.22 mm/s and 0.70,respectively,in summer,suggesting that LE was controlled by Rn during the growing season of plants.The average values of Ω were <0.5 in other seasons,indicating that LE was strongly regulated by VPD.The present study suggests that 1)Rn/Rs was relatively low despite the high incident solar radiation in the Three-River Source Region;2) the energy balance component variations were mainly controlled by Rn,LAI,and SWC;and 3) the increased artificial grassland coverage changed the processes and components of energy balance.
  • DownLoad:Energy balance of an artificial grassland in the Three-River Source Region of the Qinghai-Tibet Plateau.PDF
  • Spatial and temporal ecosystem changes in the Ebinur Wetland Nature Reserve from 1998 to 2014
  • Authors:LI Zhe, ZHANG Fei, Hsiang-te Kung, ZHANG Yue and JING Yunqing
  • Abstract:Ecosystem services are the direct and indirect contributions of ecosystems to human wellbeing and survival,and they provide cultural and economic benefits for sustaining and fulfilling the well-being of humans the living organisms.Wetlands are an important component of ecosystem environments,especially for economic and agricultural development via their roles in flood reduction and nutrient cycling,as well as water conservation,regulating atmospheric composition and maintaining biodiversity.In recent years,many researchers have studied spatial ecosystem patterns and factors influencing the value of ecosystem services,although few studies have focused on how the intensity of land use in these areas affects ecological changes.We selected the Ebinur Wetland Nature Reserve as our study site to analyze the spatial distribution and dynamics of ecosystem services.We used 1998 TM Landsat images,2006 ETM+Landsat images,and 2014 OLI Landsat images to analyze land use changes over these periods and used the computational formula from the Costanza ecosystem service value to study the auto-correlation of land use changes in the study area.The results of the study are:(1) Over the past 20 years,land use significantly changed,with all land use practices increasing except in the water area and bare land area.(2) Changes in ESV (Ecosystem Services Values) were been insignificant in the past 20 years,with ESV decreasing,suggesting that the ecological environment is subject to a degradation trend.(3) The spatial-temporal variation of ESV was prominent;spatial correlation was significant and the degree of spatial agglomeration was relatively high in the study area.High values were distributed mainly in the water area and wetland region,with these high-value regions exhibiting a decreasing trend.Low values occurred around the lake areas,which increased over time.(4) The influence of spatial-temporal changes in the ecosystem service values was insignificant and human driving factors will become the main driving forces influencing the spatial-temporal changes of ecosystem services values.
  • DownLoad:Spatial and temporal ecosystem changes in the Ebinur Wetland Nature Reserve from 1998 to 2014.PDF
  • Effect of reforestation with different tree species on soil water-holding capacity in western Sichuan province
  • Authors:CHEN Wenjing, QI Kaibin, HUANG Junsheng, YANG Tinghui, BAO Weikai and PANG Xueyong
  • Abstract:Reforestation of degraded ecosystems (e.g.,cut-clearing area or degraded secondary shrubland) is an important forest practice to restore the soil ecological function.However,there is scarce information about the effects of conversion from shrubland to plantations of different tree species on water-holding capacity of soils.To evaluate the effect of reforestation after conversion from coppice on soil water-holding capacity in the eastern Tibetan Plateau,four plantations stands were selected (each 28 years old,1987-2015),each with a different dominant tree species (namely Cercidiphyllum japonicum,Pinus tabulaeformis,Larix kaempferi,and Pinus armandii).A native broad-leaf coppice was used as the control.The four plantations were cultivated on similar site conditions,by using the same patterns of planting and management practices.We determined the soil bulk density,soil porosity,and soil water-holding capacity.Correlations between the soil physical index and the stock of litter in the forest floor and fine root biomass were used to elucidate the factors that influenced the changes in soil water-holding after replacing the native shrub by different tree species.Our results showed that compared with native broad-leaf coppice,either the deciduous or the broad-leaved plantations (C.japonicum and L.kaempferi) better improved the porosity and water-holding capacity of soils.In contrast,the evergreen pure coniferous plantations (P.armandii and P.tabulaeformis) decreased the porosity and water-holding capacity of the soils.Low rate of litter decomposition in the P.armandii and P.tabulaeformis plantations hindered the turnover of organic materials forming soil organic matter,and this may have indirectly contributed to the lower soil water-holding capacity,via influencing soil physical porosity.Additionally,the fine root biomass in different plantations may be an important factor,since it too can alter soil physical parameters,and thus,further affect the soil water-holding capacity.Our results highlighted that reforestation in a degraded ecosystem with the aim to restore soil water-holding capacity should avoid planting pure stands of coniferous tree species.Deciduous or broad-leaved tree species are appropriate tree species for improving the soil structure of monoculture plantations in the eastern Tibetan Plateau.
  • DownLoad:Effect of reforestation with different tree species on soil water-holding capacity in western Sichuan province.PDF
  • Sensitivity analysis of soil salinity and vegetation indices to detect soil salinity variation by using Landsat series images:applications in different oases in Xinjiang,China
  • Authors:WANG Fei, DING Jianli, WEI Yang, ZHOU Qianqian, YANG Xiaodong and WANG Qianfeng
  • Abstract:Several indices of vegetation and soil salinity have been developed to quantitatively evaluate soil salinization.This study was conducted to assess the soil salinity levels in the Fubei region (FG),Manas River Basin (MRB),and Werigan-Kuqa River Delta Oasis (WKRDO),which are distributed in the northern and southern Tianshan Mountains in Xinjiang,China.Ground measurements and remote sensing data were used to evaluate the sensitivity of vegetation and soil salinity indices to soil salinity variation in farmland and salt-affected land.A random sampling approach was used to collect soil samples from FG (n=37,only at 0-10-cm depth),MRB (n=58),and WKRDO (n=38).A total of 14 broadband indices encompassing vegetation and soil salinity indices were extracted from Landsat images.The correlation coefficient based on linear and non-linear models (10 models) between these indices,Landsat bands,and soil salinity was examined.The results showed that the extended enhanced vegetation index (EEVI) was the most effective for explaining the soil salinity variation at depths of 0-10 cm in two modes (all samples and partial samples with soil salinity (soil salt content)>0.3%) in FG.With the mode of all samples and partial samples (soil electric conductivity <2 dS/m) in MRB,band 2 yielded the best results for assessing the soil salinity of cultivated lands at the early stage of crop growth in April.The maximum depth of the significance test by using indices for detecting variation of soil salinity in this area was 30 cm.For all samples in WKRDO,the salinity index (SI-T) interpreted more variation of soil salinity than that by other indices at depths of 0-10 and 10-20 cm,and the three-band maximal gradient difference index (TGDVI) exhibited the highest significant correlation with salinity at 20-40 cm.In the mode of partial samples (soil salinity >2 dS/m),the most sensitive index for variation of soil salinity at 0-10,10-20,and 20-40 cm were band 5,TGDVI,and EEVI.In addition,the correlation of other indices (excluding those mentioned above) and soil salinity was highly dependent on land cover heterogeneity and sample period,and showed no significant relationships (p > 0.05 or p > 0.01).These results are preliminary conclusions,but in general,the soil salinity in Xinjiang dominated by different salt types was successfully assessed by broadband vegetation and soil salinity indices extracted from the Landsat images.However,relationships between remote sensing indices and soil salinity within fields are highly complex and require further investigation with additional samples and by using various soil salinity classifications.
  • DownLoad:Sensitivity analysis of soil salinity and vegetation indices to detect soil salinity variation by using Landsat series images:applications in different oases in Xinjiang,China.PDF
  • Dynamic analysis of vegetation change in north China
  • Authors:CAO Shixiong, LIU Guanchu and MA Hua
  • Abstract:Drylands cover approximately 54 million km2,which accounts for 40% of the global land area,and is inhabited by 20% of the human population;however,these areas are increasingly affected by desertification.Desertification is concentrated in the northwestern,northern,and northeastern parts of China (the so-called "Three Norths"):an estimated 3.3 million km2 have been affected by desertification,accounting for 34% of China's total land area.Desertification has become a crucial environmental problem at a global scale,and has begun to affect the survival and socioeconomic development of humankind.Research has suggested that both climate and human activities play important roles in the process of desertification,which is complicated and includes complex interactions between human and natural factors (e.g.,climate).However,previous research generally focused on either meteorological factors associated with climate change or factors associated with human activities,and lacked quantitative assessments of their long-term interaction.Thus,the roles of climate change and human factors in vegetation cover change and desertification are uncertain.This creates a high risk of misunderstanding the current situation and adopting ineffective policies and programs to combat desertification.It is,therefore,urgently necessary to comprehensively study the interacting effects.To understand the factors that determine whether mitigation programs can contribute to desertification control and vegetation cover improvement in desertified areas of China,and the complex interactions that affect their success,we used a pooled regression model based on panel data to calculate the relative roles of climate change and human activities on the desertified area and vegetation cover.We used the 1983 to 2012 normalized-difference vegetation index,NDVI,which decreases with increasing desertification.We found similar effect magnitudes for climate change and human activity factors for NDVI:human activity factors were the dominant factor that affected vegetation change,accounting for 58.2%-90.4% of the effects.Climate change accounted for 9.6%-41.8% of the effects on NDVI.Therefore,desertification control programs must account for the integrated effects of both socioeconomic and natural factors.Although humans are clearly part of nature,we are qualitatively different from other parts of nature:our actions have more rapid and disruptive consequences than those of most natural phenomena.Therefore,we must be careful to avoid the adoption of extreme approaches to change natural ecosystems because our changes may occur more rapidly than it is possible for the ecosystems to adapt,and the resulting problems may not be evident immediately but have long-term consequences.Our method for identifying the contributions of each driving factor was defensible for providing a broad overview.This method should be identified in future research to improve the ability of this research to support restoration planning.
  • DownLoad:Dynamic analysis of vegetation change in north China.PDF
  • Effects of Eupatorium adenophorum on interspecific association and the stability of companion species in Liangshan Prefecture of Sichuan Province
  • Authors:LIU Hai, DU Ruwan, WANG Yong, CHEN Yulan, WU Yekuan and YUAN Ling
  • Abstract:Eupatorium adenophorum is the most damaging invasive alien species in China and unbalances local ecosystems and threatens the survival of native species,thus,attracting increasing attention from all sectors of society.Exploring interspecific associations of E.adenophorum and the stability of companion species after invasion is an important starting point for studying the interaction of invasive and native species.To effectively predict and evaluate the level of E.adenophorum invasion,we investigated invaded areas in Liangshan Prefecture of Sichuan,using 2×2 contingency table analysis and χ2 and W tests to analyze interspecific associations,using the association coefficient (AC),percentage of co-occurrence (PC),Ochiai index (OI),Dice index (DI),Godron M method,of Xichang City and Huili,Huidong,Dechang,and Puge counties.There were 155 companion plant species in the E.adenophorum community in Liangshan Prefecture,including 86 herbaceous plants,34 shrubs,22 trees,10 vines,2 ferns,and 1 bryophyte.The χ2 and W tests results indicated that the variance ratio of overall association of major plants in the E.adenophorum community was 0.9677 < 1,χ0.952(50)< W < χ0.052(50),which indicates a non-significant negative correlation among the main species.The χ2 values among the various species were all lower than 3.841,indicating that the two main species were only slightly associated or even independent.Dominant species in the E.adenophorum community were similarly or equally adapted to the environment,and competition existed in the utilization of natural resources.Interspecific association analysis indicated that 20 pairs of species were positively correlated and that 22 pairs exhibited negative correlations or were completely independent.The percentages of co-occurrence of E.adenophorum with Bidens pilosa,Artemisia lavandulaefolia,Digitaria sanguinalis,and Physalis peruvianal ranged from 0.4 to 0.6,and the OI and DI indices were all over 0.6,which indicated that E.adenophorum had similar or identical ecological needs and adaptability to the environment,but also that B.pilosa,A.lavandulaefolia,D.sanguinalis,and P.peruvianal had strong resistance to the inhibitory properties of E.adenophorum.Community stability analysis indicated that the intersection point of the model equation and linear equation was 51/49,which was far from the stable intersection point 20/80,thus indicating that the E.adenophorum community was unstable.Therefore,we concluded that local plant communities in southwest China become relatively unstable after being invaded by E.adenophorum,interspecific segregation will occur to lower the competition intensity among the various species,thus the plant communities tends to be stable gradually.This conclusion could be referenced for predicting and evaluating the degree of invasion by E.adenophorum as soon as possible.
  • DownLoad:Effects of Eupatorium adenophorum on interspecific association and the stability of companion species in Liangshan Prefecture of Sichuan Province.PDF
  • Convergent adaptation of PSⅡ photochemical characteristics of four spruce species growing in Minqin Desert Botanical Garden
  • Authors:SHI Shengbo, LIU Kebiao, ZHANG Yinghua, LIU Shizeng, KANG Caizhou and LI Delu
  • Abstract:Picea mongolica,Picea crassifolia,Picea pungens and Picea meyeri are the four spruce species growing in Minqin Desert Botanical Garden (38°35'N,102°58'E;1378 m asl).In combination with the analysis of photosynthetic pigments in needles and annual growth of main braches,the chlorophyll fluorescence imaging of needles were performed with prepared protocols using CF imager to determine the PSⅡ photochemical efficiency and non-photochemical energy dissipation,and their adaptability to steady-state light intensity.The results showed that,in the same habitat and management,the four spruce species seedlings aged 15 years exhibited similar good growth behavior and all adapted to desert climatic environment;the total chlorophyll contents were fairly higher in P.pungens while specific ratio of chlorophyll a to b (Chl a/b) was comparatively lower in P.crassifolia.Among the four species their photosynthetic response curves of PSⅡ photochemical efficiency were similar,but P.pungens illustrated an obviously different photosynthetic response in PSⅡ non-photochemical quenching coefficient (NPQ) from the other three.The consistent trend of NPQ irradiated with 150 μmol m-2 s-1 low actinic light for 10 min and PSⅡ photochemical maximum quantum efficiency (Fv/Fm) adapted for 20 min in dark exhibited the intrinsic photosynthetic characteristics of the species.That nearly no dissimilarities among the four species in NPQ irradiated with 1 500 μmol m-2 s-1 high actinic light and in PSⅡ maximum efficiency (Fv'/Fm') done with low actinic light demonstrated their physiological expressions of convergent adaptation.Comprehensive comparative analysis indicates that P.pungens and P.meyeri have lower ability in PSⅡ non-photochemical quenching in low light intensity,but a relatively higher PSⅡ operating efficiency (Fq'/Fm') in high light intensity,thus a greater ability for light-acclimation;while P.mongolica and P.crassifolia share almost unanimously PSⅡ photochemical and non-photochemical characteristics,and similar shade tolerance and light-demanding;the complete presentation of PSⅡ photosynthetic physiological characteristics in the four species indicates their convergent adaptability to Minqin arid desert climate,so they are feasibly important tree species in the northern shelter forestry construction in China and in the urban greening in dry areas.
  • DownLoad:Convergent adaptation of PSⅡ photochemical characteristics of four spruce species growing in Minqin Desert Botanical Garden.PDF
  • Ecosystem carbon density of Robinia pseudoacacia plantations and influencing factors in the middle and western Loess Plateau
  • Authors:NIU Chunmei, GUAN Jinhong, CHENG Ranran, LI Guoqing, WU Chunrong, CHENG Jimin and DU Sheng
  • Abstract:Plantations are believed to be a mitigating measure against the predicted rising CO2levels.As important carbon sinks,Robinia pseudoacacia plantations have been planted extensively on the Loess Plateau owing to the ability of this species to adapt to different soil and climatic conditions and its tolerance to drought and erosion.However,little is known regarding the efficiency of R.pseudoacacia regarding biomass allocation,ecosystem carbon density partitioning,and factors influencing these aspects,especially in different planted regions.Thus,the objective of the present study was to investigate the ecosystem carbon density of R.pseudoacacia plantations and evaluate their relationship with different influencing factors in diverse planted regions.In the present study,a set of 14 sample plots were established in 4 major planted areas of R.pseudoacacia plantations (Baiyin,Pingliang,Yan'an,and Qingyang) in the middle and western Loess Plateau,China.Field investigations and laboratory analyses were undertaken to quantify the ecosystem carbon density and analyze its influencing factors.The main results are that the average biomass in the plantation ecosystems of five different age groups was 34.13-133.08 t/hm2 and the average carbon concentration of the vegetation pool was 221.93-454.67 g/kg.The average biomass in different components was significantly different among the four distribution regions,as were the average carbon concentrations of arbor layer,shrub layer,and herb layer.The carbon concentrations in the different components were in the order of:arbor layer (435.94 g/kg)> shrub layer (365.19 g/kg)> herb layer (310.53 g/kg)> litter layer (264.08 g/kg).The average carbon density of the studied ecosystems was 106.86 t/hm2.The proportion of soil layer carbon density was 64.09%,and soil layer carbon density was the major constituent of the carbon density of the ecosystem.The carbon density of the vegetation layer was 38.68 t/hm2.The carbon density of the arbor layer was 33.88 t/hm2,which accounted for 87.58% of the vegetation layer carbon density.The carbon density of the shrub layer,herb layer,and litter layer were 0.77 t/hm2,0.77 t/hm2,and 3.26 t/hm2,respectively,which accounted for 1.98%,2.00%,and 8.43% of the vegetation layer,respectively.Soil organic carbon density and ecosystem carbon density were all significantly different among the four regions.Correlation analysis indicated that ecosystem carbon density was positively correlated with stand age and precipitation.In contrast,its relationships with forest stand density,slope gradient,elevation,and annually mean temperature were not statistically significant.Principal component analysis indicated that stand age and precipitation were the first principal component affecting ecosystem carbon density;elevation and annually mean temperature were the second principal component;and the slope gradient was the third principal component.These variables accounted for 91.07% of the variance of ecosystem carbon density.The effect of different factors on ecosystem carbon density was discrepant.Stand age and precipitation were the primary factors affecting ecosystem carbon density.The differences in forest ecosystem carbon density were due to the combined effects of climate,topography,forest stand factors,and management.Therefore,these influencing factors need to be considered when using forest-investigated data to estimate forest ecosystem carbon stock,especially at larger scales.
  • DownLoad:Ecosystem carbon density of Robinia pseudoacacia plantations and influencing factors in the middle and western Loess Plateau.PDF
  • Characteristics of transpiration and evapo-transpiration from natural Larix gmelinii forests on rainy and non-rainy days
  • Authors:LIU Jialin and MAN Xiuling
  • Abstract:We continuously measured the transpiration of different tree differentiation classes and ecosystem evapotranspiration using the sap flow method and eddy covariance technique in a natural Larix gmelinii-dominated boreal forest located in the Northern Great Hinggan Mountains.The sapwood area of stem was used for scale expansion from single stand to forest.We examined variations in total transpiration of the forest (Ttot) and its three components,namely,the transpiration of dominant (Td),intermediate (Ti),and suppressed (Ts) trees,and measured ecosystem evapotranspiration (ET).We also analyzed the regression correlations between Ttot or ET and vapor pressure deficit (VPD) and net radiation (Rn).The results showed that daily variation in sap flow velocity in different tree differentiation classes exhibited a unimodel pattern on both rainy and non-rainy days.Ttot on rainy days (24.7 mm) was lower than that on non-rainy days (50.6 mm),and Td was higher than Ti and Ts on both rainy and non-rainy days.ET on rainy days (24.7 mm) was lower than that on non-rainy days (50.6 mm);however,the ratio of latent heat to Rn on rainy days (31%) was higher than that on non-rainy days (25.1%),indicating that environmental conditions on non-rainy days were more conducive to water vapor exchange over the interface between the atmosphere and plant stoma.The values of Ttot/ET,Td/ET,Ti/ET,and Ts/ET on rainy days (38.1%,27.2%,8.5%,and 2.4%,respectively) were lower than those in non-rainy days (65.0%,45.5%,15.3%,and 4.2%,respectively).This finding demonstrates that evaporation represented the principal water loss in ET on rainy days,whereas on non-rainy days,ET was dominated by transpiration.This,however,would overestimate the forests'transpiration capacity when scaled up considering only dominant tree transpiration consumption.In general,it was found that the correlation between Ttot and environmental variables (i.e.,VPD and Rn) is better than that between ET and these variables,which indicates that Ttot is more sensitive to environmental variations.Furthermore,the correlation between Rn and water vapor fluxes (i.e.,Ttot and ET) is better than that between VPD and water vapor fluxes,indicating that Rn is the primary driver of an ecosystem's water vapor fluxes.
  • DownLoad:Characteristics of transpiration and evapo-transpiration from natural Larix gmelinii forests on rainy and non-rainy days.PDF
  • Plant colors at multiple scales and their effects on humans
  • Authors:ZHANG Zhe, QIE Guangfa, WANG Cheng and JIANG Shasha
  • Abstract:The first aspect noticed in the appearance of plants is usually their colors,which is associated with human reactions to their visual characteristics.Therefore,color plays an important role in the promotion and public suitability of forest scenic beauty.This paper summarized the milestones in chromatics formation and research trends of plant color over the past century.The developing course of plant color research can be divided into germination,formation,evolution,and flourishing periods.Simultaneously,the main characteristics of each stage have been analyzed.The mechanisms of expression generated by plant color and the relevance between color and human reactions were reviewed through four visual scales,including plant organs,individual plants,population and community of plants,and overall landscape.In this review,three levels of influence including aesthetics,physical,and mental,were identified.Several defects on plant color extraction,such as color element ration,feature factor selection,and color quantization were detected and through them,five key directions were elucidated for future research:1) analysis of the association between plant colors and different scales as well as human reactions to them;2) in-depth study on plant color evaluation factors in a large scale;3) multidisciplinary fusion of the color quantization method;4) comprehensive comparison of public reactions to plant color;and 5) practice of forest scenic beauty promotion.The present study will contribute to a comprehensive understanding of the mechanisms and influences of plant color expression,as well as scientific studies on plant color under different precisions and scales.
  • DownLoad:Plant colors at multiple scales and their effects on humans.PDF
  • Effects of population density on the biomass allocation and allometric growth of Chenopodium acuminatum
  • Authors:FAN Gaohua, CUI Zhen, ZHANG Jinwei, HUANG Yingxin, SHEN Xiangjin and ZHAO Xueyong
  • Abstract:The organs of plants have different functions and the allocation ratio of organ biomass is closely related to the ability to obtain resources for the plants.Plants organs present allometric phenomena during growth and development.By simulating the growth characteristic of Chenopodium acuminatum in different densities (16,44.4,100,and 400 plants/m2),we used allometry analysis to study the effects of density on the biomass allocation and allometric growth of C.acuminatum.The results showed that,with the increase of density,there were different levels of competition for both aboveground and belowground organs,ie.,the distribution of root and main stem increased,and the distribution of stem and aboveground organs decreased,but the distribution of leaves and reproductive organs did not change with the density.There were significant allometric relationships between each pair organs.The changes of leaves vs.main stem,root vs.aboveground organs,root vs.stem,root vs.main stem,reproductive vs.aboveground organs,and reproductive vs.root of biomass were not affected by the density,with these exhibiting ‘apparent’ plasticity.The allometric relationships of biomass in leaves vs.aboveground organs,leaves vs.root,leaves vs.stem,stem vs.aboveground organs,main stem vs.aboveground organs,reproductive organs vs.stem,and reproductive organs vs.main stem were significantly affected by density,representing ‘true’ plasticity.The results showed that density could affect the growth of C.acuminatum.The allometric index of biomass between leaves vs.main stem,leaves vs.root and main stem vs.aboveground organs in 400 plants/m2 was close to 3/4,which is in accord with the metabolic theory of ecology,while the allometric indexes were significantly (P<0.001) different from 3/4 among other densities.This suggests that the plants with complete competition are more likely to conform to the predictions of metabolic theory,while plants with weak competition exhibit species-specific resource investment.
  • DownLoad:Effects of population density on the biomass allocation and allometric growth of Chenopodium acuminatum.PDF
  • Changes in plant biomass and its seasonal dynamics during degradation succession in the Gahai wetland
  • Authors:MA Weiwei, WANG Hui, LI Guang, SHI Wanli, ZHAO Jinmei, LUO Yongzhong, NIE Zhigang and XUE Jingwen
  • Abstract:Wetlands are important contributors to the global carbon (C) cycle because they store large quantities of C in their vegetation and soil and exchange CO2 actively with the atmosphere through photosynthesis and respiration.Plant biomass is a critical part of the primary production in wetland ecosystem that maintains the wetland health and quality.It also provides many ecosystem functions,such as C sequestration in alpine wetland.Therefore,biomass is the main link that relates aboveground and belowground ecosystem processes.We used the peatlands and swamp medows areas in the Gahai wetland of south Gansu province to investigate changes to plant biomass during degradation succession in an alpine wetland.The time-space distribution pattern of the area at different stages of wetland degradation was analyzed using the sample-plot survey method.Significance testing was conducted using one-way variance analysis (One-way ANOVA) and the Schaffer method.The results showed that 1) the aboveground biomass decreased gradually in the peatlands and swamp medows as degradation succession progressed.The reduction in aboveground biomass followed the order non-degraded peatlands (PI)(334.19 g/m2)> degraded peatlands (PⅡ)(290.72 g/m2),and was non-degraded swamp meadows (SI)(378.40 g/m2)>lightly degraded swamp meadows (SⅡ)(308.07 g/m2)> moderately degraded swamp meadows (SⅢ)(261.21 g/m2).The curves for the aboveground biomass seasonal dynamics for the two sites were seasonal dynamics of aboveground biomass was single apex types,the variation trends were the same,and they reached a peak value in August.The changes in the absolute growth rate and relative growth rate of aboveground biomass at each degradation stage on the same wetland types were consistent for each degradation stage on the same wetland types over the years the survey took places,but the values were different between years.The values for absolute growth rate and relative growth also varied depending on the degradation stage in the same wetland type.2) The belowground biomass decreased significantly in the two wetland types as degradation succession (P<0.05).The belowground biomass in PI was 23081.46 g/m2 and was 12607.72 g/m2 for PⅡ in the peatlands,and followed the order SI (4583.16 g/m2)> SⅡ (3008.63 g/m2)> SⅡ (1290.73 g/m2) in the swamp meadow.The seasonal variations in belowground biomass for each wetland type were different,but the earlier the growing season began and ended,the greater was the amount of belowground biomass.Belowground biomass decreased significantly (P<0.05) with soil depth and had a "T" shape distribution.The peat and swamp meadow belowground plant biomass was greatest in the 0-10 cm soil layer,and occupied more than 50% and 70% of their total belowground biomasses,respectively.3) The average root-shoot ratio for non-degraded wetland was higher than for degraded wetland between May and September.The root-shoot ratio seasonal dynamics showed that the earlier the growing season began and ended,the greater was the ratio,and the shorter the period of vigorous growth.These results provide a scientific basis for wetland planning and management and an accurate estimation of C balances in alpine wetland ecosystems.
  • DownLoad:Changes in plant biomass and its seasonal dynamics during degradation succession in the Gahai wetland.PDF
  • Assessing the ecological health of Poyang Lake wetland using a vegetation-based index of biotic integrity (V-IBI)
  • Authors:XU Liting, YANG Wenjing, WU Yanping, YOU Qinghui, HUANG Qi, XU Yu and WANG Yeqiao
  • Abstract:Assessing the ecological status of wetlands can provide critical information for the governance and management of wetland ecosystems.The index of biotic integrity (IBI) is a comprehensive method for assessing the ecological health of wetlands.Initially developed in North America,this method has standardized protocols for implementation and practice.The quantitative assessment results are easy to understand and communicate among scientific communities and the general public.Vascular plants are quickly emerging as one of the important indicators of human-mediated disturbances,because they are immobile,and therefore,susceptible to physical,chemical,and biological changes of the surrounding environment.Poyang Lake is the largest freshwater lake in China.The Poyang Lake wetland is recognized as one of the most important wetlands in the world since it provides habitats for many unique species of wintering migratory birds and is of prominent ecological and economic importance to millions of people in the middle and lower Yangtze River basin.Poyang Lake wetland has been significantly altered by human activities,such as agriculture,fishing,and tourism.Currently,there is no indicator framework to determine the status and trends of conditions of the Poyang Lake wetland.In this study,we aimed to develop a vegetation-based IBI (V-IBI) to assess the ecological health of Poyang Lake wetland.Field surveys of 30 sampling sites were conducted in the autumn of 2015.We collected data including plant species compositions,abundance,water quality parameters,soil properties,and land use surrounding sampling sites.We tested 35 candidate metrics regarding the diversity,structure,and disturbance tolerance of plant communities for their discriminatory ability between reference sites and impaired sites.Six metrics were finally selected as the V-IBI metrics,i.e.,numbers of invasive species,sensitive species,tolerant species,perennial species,species with both sexual and vegetative propagation,and percentage cover of Phalaris arundinacea L.Values of these metrics were scaled between 0 and 1.The V-IBI score of a sampling site was calculated as the sum of the scaled values of each individual metric.A 95% percentile of all V-IBI scores and quartiles of the scores below the 95% percentile were then used as cut-offs for rating categories.The results showed that 6 sites were rated as excellent (V-IBI ≥ 5.01);7 were good (4.38 ≤ V-IBI < 5.01);8 were fair (3.74 ≤ V-IBI < 4.38);7 were poor (3.10 ≤ V-IBI < 3.74);and 2 were very poor (V-IBI<3.10).Sampling sites rated as excellent and good were all located in western and northern sections,especially within the national and provincial nature reserves,whereas those rated as poor and very poor were mostly located in eastern and southern sections where wetland health was impaired by dense populations and intensive agricultural practices.Wetland areas where rivers discharged into Poyang Lake were generally rated as poor,suggesting that pollutants brought in by rivers had negative impacts on wetland health.The V-IBI was significantly correlated with the index of landscape development intensity (LDI) and qualitative habitat evaluation index (QHEI),indicating that V-IBI is plausible and reliable for assessing the ecological health of the Poyang Lake wetland.
  • DownLoad:Assessing the ecological health of Poyang Lake wetland using a vegetation-based index of biotic integrity (V-IBI).PDF
  • Research on the global ecological suitability and characteristics of regions with Angelica sinensis based on the MaxEnt model
  • Authors:ZHANG Dongfang, ZHANG Qin, GUO Jie, SUN Chengzhong, WU Jie, NIE Xiang and XIE Caixiang
  • Abstract:In order to investigate the global ecological suitability and characteristics of regions for the medicinal plant Angelica sinensis,a maximum entropy model (MaxEnt) and geographic information system (GIS) technology were used to investigate global ecology suitability regions based on 109 sample points of A.sinensis and 37 ecological factors.The results showed that global ecological regions that are suitable for A.sinensis are located mainly in the range of 20-50°N and 15-35°S,which includes sections of North America,Europe,Asia,South America and Africa.The total area of suitable regions found was about 5930700 km2.The regions with the most similarity were found to be mainly in the south of Gansu province,Sichuan,the east of the Tibet Autonomous Region,the north of Yunnan province,Guizhou,the southwest of Shanxi province,and other nearby regions.These results signify that China is very suitable for the cultivation and production of A.sinensis.The climatic factors that were found to affect the distribution of A.sinensis were mainly precipitation during warmest quarter,mean temperature of the coldest quarter,and the coefficient of variation of precipitation seasonality,with the most suitable value ranges being 300-700 mm,-3-7℃ and 70-98 respectively.The soil factors affecting the distribution of A.sinensis were found to be mainly the calcium carbonate (lime) content and percentage clay,the value ranges of which were found to be 60%-0% and 17%-24%,respectively,in the ecologically suitable regions.These results provide a scientific reference for the refinement of the artificial cultivation of A.sinensis.
  • DownLoad:Research on the global ecological suitability and characteristics of regions with Angelica sinensis based on the MaxEnt model.PDF
  • Temporal and spatial distribution of net ecosystem productivity in the Bailongjiang Watershed of Gansu Province
  • Authors:GONG Jie, ZHANG Ying and QIAN Caiyun
  • Abstract:Net ecosystem productivity (NEP) is an important factor for the regional estimation of carbon sources and carbon sinks,and the accurate estimation of these components of the carbon cycle is imperative to be able to predict climate change and establish reasonable environmental policies.In this study,we analyzed the temporal and spatial distribution of net ecosystem productivity on a unit area basis in the Bailongjiang Watershed,Gansu Province,China,from 2000-2013 via using MODIS and meteorological data and then explored the relationship between NEP and topographical factors.Four primary results were obtained:(1) The mean annual NEP was 226.65 g C m-2 a-1 from 2000 to 2013 in the watershed,and the carbon sink area accounted for 97.20% of the whole watershed area.The carbon sinks were mainly distributed in forest land along both sides of the upper Bailongjiang,the west bank of the Minjiang,the southern bank of the Baishuijiang,and both banks of the Datuanyu River.The carbon source areas were mainly distributed in the Wudu District and the northern border area of Diebu County.(2) Mean annual NEP was highest for evergreen broad-leaved forest and mixed evergreen and deciduous,broad-leaved forest followed by the mountain steppe.Mean annual NEP for cultivated land,coniferous forest,and shrubland was similar,and even smaller for the alpine steppe.While NEP tended to increase over time in cultivated land,the trend was a slight decline in mixed evergreen and deciduous,broad-leaved forest.(3) There was significant spatial heterogeneity in the trends of how NEP changed over time.Specifically,NEP tended to increase in the Bailongjiang Watershed,which accounted for 64.00% of the study area and were mainly distributed in the central and northwest regions of the watershed,particularly in the mid-Bailongjiang River,and NEP that tended to decrease was mainly distributed in the centre of Wudu District.Additionally,the period from April to September is when both NEP and the carbon sink areas increase.(4) Topographical factors played an important role in NEP in the Bailongjiang Watershed.The area below 4200 m was the primary carbon sink area,and the NEP growth rate and carbon sink capability on steep slopes (over 40 degrees) were higher than in areas with a gentler slope.Further,the capacity of carbon sinks on shady slopes was higher than for those on sunny slopes.
  • DownLoad:Temporal and spatial distribution of net ecosystem productivity in the Bailongjiang Watershed of Gansu Province.PDF
  • Soil microbial community structure and composition of Stipa Breviflora on the desert steppe
  • Authors:GAO Xuefeng, HAN Guodong and ZHANG Guogang
  • Abstract:The desert steppe is one of the most concentrated distribution in the Inner Mongolia region and representative types of temperate grassland in China for studying systems ecology.The desert steppe is located at the grassland-desert ecotone,and is an ecosystem that is very sensitive to global changes.However,Grassland degradation has seriously affected the function and productivity of this ecosystem under the dual pressures of continuous drought and long-term overgrazing.Grassland degradation not only affects local agricultural production and everyday human life,but also threatens the ecological environment of central cities in china.This has become an urgent regional environmental issue,especially for the sustainable development of animal husbandry.Today most research on the desert grassland ecosystem examines vegetation characteristics,physical and chemical soil properties,animal behavior,and so on.However,less research exists on the underground soil microbial community structure.The Inner Mongolia desert grassland is an important part of the grassland in north China,with a unique plant species composition and range of community types,structures,and functions.Soil microbial communities are also important components of grassland ecosystems.They are dominant contributors to biogeochemical cycles,participating in the decomposition of organic material in soil,and are critical for maintaining the stability and biodiversity of grassland ecosystems.Research on the soil microbial community structure and diversity of Stipa breviflora(needlegrass)on the desert steppe in Inner Mongolia will have important ecological significance to the rational utilization of grassland,will contribute to understanding the biological functions involved in restoring degraded grassland ecosystem,and will help realize the sustainable development of grassland ecosystems.In order to understand the characteristics of the soil microbial community structure of the S.breviflora desert steppe in Inner Mongolia,we adopt high-throughput sequencing technology to relatively comprehensive research the soil microbial community structure of S.breviflora on the desert steppe in Inner Mongolia.We extracted DNA of the soil microbial community of the desert steppe in Inner Mongolia.Soil bacterial community structures of the v4-v5 16S rDNA gene region and fungi community structures of ITS1-ITS2 were examined by high-throughput sequencing technologies.The results showed that 13711 and 5929 OTUs were obtained from soil bacterium and fungi.Based on the results of species classification,bacterial communities belonging to 29 phyla,57 classes,111 orders,191 families,and 485 genera.Among them,the dominant populations were Gammaproteobacteria and Thermoleophilia,and their relative abundances were 32.68% and 26.83%.Fungal species belonged to 4 phyla,16 classes,45 orders,78 families,and 105 genera.The dominant species were Ascomycota and Basidiomycota,and their relative abundances were 35.76% and 25.90%.Bacterial communities were more diverse and had greater species richness than fungal community in the soil.
  • DownLoad:Soil microbial community structure and composition of Stipa Breviflora on the desert steppe.PDF
  • Effect of subsoiling on soil nutrient and microbe functional diversity of Glycyrrhiza uralensis rhizospheres
  • Authors:ZHANG Zhizheng, MA Miao and ZHANG Xulong
  • Abstract:As a fundamental soil component,soil microorganisms can sensitively,timeously,and accurately reflect the status of the change of soil quality and reveal the condition of soil fertility and improvement,which are important indicators of soil quality.At present,subsoiling technology is considered a soil conservation-tillage technology,which can change the soil structure and influence the soil microbial community.Therefore,the effect of tillage methods on microbes in soil ecosystems is being well studied globally.However,little is known about effect of subsoiling on soil nutrients and the functional diversity of microbial communities in rhizosphere soil of Glycyrrhiza uralensis.The purpose of this study was to provide the basis for improving tillage practices and soil environmental condition of licorice.Compared to conventional methods,Biolog technology can effectively provide useful information on soil microbial community functional diversity.Therefore,in this study,two treatments,including rotary tillage (CK) and subsoiling,were conducted in licorice planting land.Using field experiments and laboratory analysis,the effect of subsoiling on soil nutrients and the functional diversity of microbial communities in rhizosphere soil of G.uralensis was determined.The results showed that the effect of subsoiling on soil nutrients in the 0-20 cm depth of rhizosphere soil of G.uralensis was not significant,but greatly improved the total nitrogen (TN),phosphorus (TP),and potassium (TK) contents in the 20-40 cm depth of rhizosphere soil of G.uralensis(which increased by 60.8,65.3,48.9,and 86.8%,respectively).Meanwhile,the number and abundance of bacteria,fungi,and actinomycetes within the 0-20 and 20-40 cm depths of rhizosphere soil of G.uralensis was significantly increased (P < 0.05).The quantity of three types of microorganisms present in the upper layer was greater than in the lower layer,and was greater in the subsoiling than non-subsoiling.After 156 h of microbial incubation,Average Well Color Development (AWCD) of different soil layers of subsoiling treatments were obviously higher than those of non-subsoiling treatments,and subsoiling treatment significantly improved the utilization of AWCD (72 h,P < 0.05),by 35.5 and 130.8% in the upper and lower soil layers,respectively.Compared with the non-subsoiling treatment,subsoiling significantly increased the microbial diversity index (such as the Shannon Index (H),Substrate Richness Index (S),and Simpson's Dominance Index (D)).A principal component analysis (PCA) showed that subsoiling treatment could optimize microbial community composition in licorice rhizosphere soil;polymers,carboxylic acids,amino acids,and carbohydrates were primary carbon sources of rhizosphere soil microbes in subsoiling areas.Overall,the nutrient content of soil,the number of microbes,and the microbial community diversity index were obviously improved by subsoiling in licorice rhizosphere soil,and the microbial community functional diversity was changed.The arable layer soil structure was enhanced,and therefore the survival of microorganisms was improved by subsoiling.Therefore,subsoiling treatment could effectively improve the quality of rhizosphere soil of G.uralensis.
  • DownLoad:Effect of subsoiling on soil nutrient and microbe functional diversity of Glycyrrhiza uralensis rhizospheres.PDF
  • Impacts of two typical earthworms on soil microbial community structure and physicochemical properties in a greenhouse vegetable field
  • Authors:WANG Xiao, WANG Shuai, TENG Mingjiao, LIN Xiaofen, WU Di, SUN Jing, JIAO Jiaguo, LIU Manqiang and HU Feng
  • Abstract:Earthworms are considered one of the most important soil ecosystem engineers.Earthworms play critical roles in soil functioning through their burrowing,feeding,and casting activities.There are distinct ecological strategies (i.e.,food selection,ingestion,assimilation,and habitat preference) for different earthworm ecotypes.Consequently,different earthworm ecotypes would have different effects on soil properties.Understanding the impacts of different earthworms on soil microbial communities would increase our mechanistic understanding of the role of earthworms in ecosystem services.Several studies have shown that earthworms facilitate the translocation of fresh residues into soil and create suitable habitat (casts,middens and burrows) for other soil organisms.Moreover,the interaction of earthworm feeding strategies and organic amendment could profoundly modulate soil properties and microbial community structure.However,there is a knowledge gap in this respect.In particular,few studies have been conducted under field conditions.To understand the long-term impact of earthworms and manure on soil microbial community structure,a tomato-spinach rotation experiment was initiated in 2009.Based on the soil collected during the fourth year following the set-up of the field experiment,the effects of two typical earthworms (i.e.,endogeic Metaphire guillelmi and epigeic Eisenia foetida) and two manure application treatments (i.e.,surface mulch and incorporation into the soil) on soil microbial community were investigated.The native endogeic species,Metaphire guillelmi,lives in the upper soil layers and primarily consumes soil mineral particles rich in organic matter,whereas E.foetida,a well-known epigeic species,resides mainly in the upper organic layers and feeds on litter materials.Our results demonstrated that soil microbial community structure was significantly affected by earthworm species and the method of manure application.With manure application at the soil surface,earthworms could significantly decrease mycorrhizal fungi,fungi biomass and protozoa biomass independent of earthworm type (P < 0.05).When manure was incorporated into the soil,M.guillelmi significantly increased mycorrhizal fungi,fungi biomass and actinomyces biomass,although the effect of E.foetida was not significant.Regardless of type,earthworms significantly increased soil porosity,soil aggregate stability represented by mean weight diameter and pH,soil mineral nitrogen,available phosphorus,as well as microbial biomass carbon and nitrogen content.In addition,the extent of increase depended on earthworm ecotype and the method of manure application.Redundancy analysis showed that earthworm-mediated microbial community structure was positively correlated with soil aggregate stability as expressed by mean weight diameter,pH,and available phosphorus content,whereas it was negatively correlated with soil bulk density.
  • DownLoad:Impacts of two typical earthworms on soil microbial community structure and physicochemical properties in a greenhouse vegetable field.PDF
  • Diversity of endophytic fungi from the stem and leaf of Sinopodophyllum hexandrum(Royle) Ying
  • Authors:NING Yi, LI Yanling, LI Yuan, ZHOU Guoying, YANG Lucun and XU Wenhua
  • Abstract:In this study,endophytic fungal diversity of the host plant Sinopodophyllum hexandrum(Royle) Ying was investigated at five locations in Qinghai,Gansu,and Sichuan Provinces.The endophytic fungi on the stems and leaves of the host plants were isolated on two culture media,potato dextrose agar (PDA) and Sabouraud dextrose agar (SDA),and the strains were identified using morphological and molecular analyses.A total of 141 endophytic fungi were isolated from 720 tissue samples.These fungi were divided into 52 endophytic taxa on the basis of their morphology in the culture media.Phylogenetic analysis based on the internal transcribed spacer region indicated 19 genera,18 of which belonged to Ascomycetes and 1 to Basidiomycetes.The number of genera varied among the five locations:10 were detected in Ruoergai County,6 in Datong County,6 in Ledu County,5 in Huangzhong County,and 5 in Xiahe County.With respect to tissue type,16 genera were isolated from the stems,6 from the leaves,and only 3 were found in both tissues.Further analysis showed that Paecilomyces was the most dominant genus,with an isolation frequency of 26.34%,followed by Leptosphaeria,with an isolation frequency of 14.89%.The community structure clearly differed among the locations.At the sites in Xiahe County,Datong County,and Ledu County,the dominant genus was Paecilomyces and the isolation frequencies were 42.31%,56.52%,and 33.33%,respectively.The dominant genus was Leptosphaeria in Ruoergai County and Septoria in Huangzhong County,with isolation frequencies of 26.83% and 38.10%,respectively.Shannon's diversity index ranged from 0.71 to 1.41 and was the highest in Ruoergai County and the lowest in Huangzhong County.Sorenson similarity index ranged from 0.13 to 0.50;it was the highest between Datong County and Ledu County and the lowest between Ruoergai County and Huangzhong County.The colonization rate of the endophytic fungi at the five locations ranged from 14.58% to 28.47%;the mean colonization rate was 19.58%,and the highest colonization rate was observed in Ruoergai County and the lowest colonization rate in Huangzhong County.In addition,the colonization rate was higher in SDA (21.67%) than in PDA (17.50%) and higher in the stem (29.72%) than in the leaf (9.44%).These findings revealed that the species diversity of the endophytic fungi in the stem and leaf tissues of S.hexandrum was low,but the community structure of S.hexandrum differed substantially among the sampling sites.Endophytic fungi that colonize stem and leaf tissues are targets for the production of podophyllotoxin and other natural compounds and,accordingly,have potential practical applications.This study offers a novel strategy for identifying valuable microbial strains from S.hexandrum.
  • DownLoad:Diversity of endophytic fungi from the stem and leaf of Sinopodophyllum hexandrum(Royle) Ying.PDF
  • Castor fiber birulai lodge site selection and characteristics in the Ulungur watershed of Xinjiang,China
  • Authors:DU Congcong, CHU Wenwen, ZHEN Rong, DUAN Xiaonan, CHEN Gang and CHU Hongjun
  • Abstract:From November to December 2014 and in April 2015,the Castor fiber birulai(Xinjiang beaver) lodge site selection and characteristics in the cold and early warm seasons in the Ulungur watershed of Xinjiang were investigated by line transect and plot sampling methods.In the cold and early warm seasons,a total of 160 and 158 lodge sites were found respectively,which indicated that there were 160 and 158 beaver families.There were 61 beaver families that built lodges on the ground,which accounted for 38.13% of lodge sites in the cold season and 38.61% in the early warm season.Mean lodge lengths were (2.54±1.69) m,while the widths were (1.68±0.91) m,and their heights were (0.54±0.32) m.Compared with that of the cold season,the C.f.birulai lodge site selections of the early warm season had the following characteristics:the nearby river was wider,deeper and bigger,its bank slope was steeper,and the surrounding vegetation canopy was larger.The vegetation canopy was affected by seasonal weather changes,which did not have significant effects on other habitat factors.Illustrated by the case of the cold season,after 17 environmental variables possibly pertaining to beaver lodge site selection were measured and analyzed,the results showed that the Xinjiang beaver lodge sites were mainly located at high-elevation (>1000m) near water areas with width and area suitable for living,with characteristics including high river banks (>1.0m),steep slopes (>75°),and deep water (>1.0m).The environment of beaver lodge sites was covert,where vegetation characteristics included high crown and tree density,and low density and height of shrubs.The beaver lodge sites were usually located on the opposite river bank of nearby human roads and houses.Furthermore,the vast majority of beaver lodge sites were in high-density willow forests and near a food cache.The beaver lodge site selections are heavily influenced by human activities;hence,measures should be taken immediately to protect the Xinjiang beaver,such as seeking other fit habitats for beavers to live in based on the stated selection characteristics,reducing the number of human dams in the Ulungur watershed,or building migration channels for beavers near human dams,thereby strengthening the protection and management of C.f.birulai in its distribution area.
  • DownLoad:Castor fiber birulai lodge site selection and characteristics in the Ulungur watershed of Xinjiang,China.PDF
  • The matebolize response of different physiological performances to decreased temperature in Spinibarbus sinensis
  • Authors:QIN Yinglian, BAI Yang, FU Kangkang and FU Shi
  • Abstract:To investigate the matebolize response of different physiological performances to decreased temperature of long-term high-temperature-acclimated juvenile qingbo (Spinibarbus sinensis),the experimental fish were reared at 15 or 25℃ for 8 weeks,respectively;then the temperature of the 25℃ group was decreased to 15℃(treatment group),and the temperature of the 15℃ group remained the same (control group).The thermal tolerance capacity (critical maximum temperature,CTmax and critical minimum temperature,CTmin),maximum sustainable swimming speed (critical swimming speed,Ucrit),spontaneous activities (percent time spent moving (PTM) and total distance moved (TDM)),specific dynamic action (peak postprandial metabolic rate (PMR)),and growth performance (feed rate,feed efficiency,and weight gain) of fish in both temperature groups were measured at 1,2,4,and 8 weeks after the temperature was decreased.There was no significant difference in cold tolerance capacity as suggested by CTmin between the treatment and control groups,whereas the heat tolerance capacity,as suggested by CTmax of the treatment group,was significantly higher than that of the control group one week after the temperature decrease,and thereafter there was no difference between the groups.The temperature decrease resulted in a significant improvement of spontaneous activities suggested by higher PTM and TDM than those of the control group (P < 0.05),and such differences persisted throughout the experimental period.The Ucrit of the treatment group was significantly lower than that of the control group at 1 and 2 weeks after the temperature decrease,and the impaired swimming capacity disappeared after 4 weeks of temperature acclimation.The PMR and SDA duration did not show any differences between the treatment and control groups from 1 to 4 weeks after the temperature decrease.The food efficiency and weight gain of the treatment group were generally lower than those of the control group,although the treatment group unusually showed a higher food rate.This suggested that there were profound differences among response speeds of different physiological performances to decreased temperature,which were possibly related to differences in their ecological correlations and underlying mechanisms.The temperature decrease in the treatment group resulted in impaired growth performance,which was mainly due to the additional energy expenditure involved in thermal stress responses,regulation of physiological functions,and elevated spontaneous activities.
  • DownLoad:The matebolize response of different physiological performances to decreased temperature in Spinibarbus sinensis.PDF
  • Seasonal distribution of body length and abundance of Aidanosagitta crassa(Tokioka,1938) in Laizhou Bay,Bohai Sea
  • Authors:ZUO Tao, WANG Jun and SHI Yongqiang
  • Abstract:Aidanosagitta crassa(Tokioka,1938) is the only dominant chaetognatha species in Laizhou Bay,Bohai Sea.This gelatinous species plays an important role in the ecosystem of Laizhou Bay,acting as the major carnivorous predator of small invertebrate and fish larva.In addition,it has different morphs responding to variations in environmental factors.To determine the population structure in Laizhou Bay,the detailed body size and abundance of A.crassa were analyzed monthly from 147 vertical net samples collected from May 2011 to April 2012(excluding December 2011 and January and February 2012,because of the presence of sea ice).Results showed that A.crassa occurred continuously and was distributed extensively throughout the survey seasons and area in the bay.Both the abundance and biomass of the species presented two peaks,a considerable peak in May,and a second peak during August to September.Individuals with a body length of about 4 and 15 mm were the major contributors to the total abundance and biomass,respectively.The production of the A.crassa population was estimated to be 0.25 mg C m-3 d-1,whereas the feeding rate was 0.88 mg C m-3 d-1 during the survey months.The body size of A.crassa fluctuated seasonally,with the largest sizes in March and April (mean body length > 10 mm),and the smallest in May and November (mean body length < 5 mm).The mean body length of the species showed an inverse correlation with both surface water temperature (SWT) and surface water salinity (SWS) of the corresponding period.Based on length-frequency distributions,different types of population pyramids occurred,namely,the expanding type in May to November except in June,stationary type in March to April,and constrictive type in June.The growing season for the A.crassa population in Laizhou Bay was presumed to be from May to August,because of the presence of abundant small individuals.Moreover,from the monthly length-frequency distributions,three common normalized cohorts (I,Ⅱ,Ⅲ) were detected with mean lengths of <5,5-10,and >10 mm,respectively.Regarding their spatial distributions,individuals of cohorts Ⅲ and I were the most abundant at sites with an SWT of 15-17℃ and SWS of 29-32 during spring.However,cohort Ⅲ showed a considerable negative correlation between its abundance and water temperature,with a limited abundance at warm sites with an SWT > 24℃.Additionally,cohort I showed a positive correlation between its abundance and water temperature,and showed a limited abundance at cold sites with an SWT < 11℃.Cohort Ⅱ was most abundant at sites with an SWT of 26-27℃ and SWS of 30-32 during autumn.From above the results,it was assumed that the water temperature threshold was lower than 15-17℃ for the transformation between the two typical size morphs,i.e.,the large winter and small summer forms of A.crassa.
  • DownLoad:Seasonal distribution of body length and abundance of Aidanosagitta crassa(Tokioka,1938) in Laizhou Bay,Bohai Sea.PDF
  • Theoretical analysis of the index system and calculation model of carrying capacity of land ecological-production-living spaces from county scale
  • Authors:FANG Chuanglin, JIA Kejing, LI Guangdong and WANG Yan
  • Abstract:Land holds the function of ecological,production and living at the same time.Correspondingly,it possesses the synthetic carrying capacity of ecological-production-living spaces,and the ecological carrying capacity,production carrying capacity and living carrying capacity are mutual support and interdependence.The synthetic carrying capacity of land ecological-production-living spaces means the capacity of mutualistic symbiosis between the land resource and ecological environment,and economic and social development ability with high standard of living.It consists of a support layer and a presentation layer.The ecological carrying capacity is support layer,and the production carrying capacity and living carrying capacity are presentation layers.Thus,the synthetic carrying capacity of land ecological-production-living spaces is called "San Sheng carrying capacity" for short.The Eighteenth National Congress of the Communist Party of China claimed, "We should improve development of China's geographical space,and ensure that the space for production is used intensively and efficiently,that the living space is livable and proper in size,and that the ecological space is unspoiled and beautiful." Based on this,we analyzed the basic composition and function mechanism of the synthetic carrying capacity of land ecological-production-living spaces,and a comprehensive index system from county scale is constructed by multi-scheme comparison,which including a primary index,three secondary indexes,22 three-level indexes.The quantitative calculation method of each index was also given.At last,we proposed a system dynamics model to account and simulate the synthetic carrying capacity of land ecological-production-living spaces.This study aims at providing a scientific criterion for promoting intensive utilization of land ecology,production and living spaces,and providing methods for the land comprehensive carrying capacity monitoring and early warning in China at the county scale.
  • DownLoad:Theoretical analysis of the index system and calculation model of carrying capacity of land ecological-production-living spaces from county scale.PDF
  • Study on ecological costs for waste paper recycling system based on the Material Flow Analysis
  • Authors:DAI Tiejun and ZHAO Xinrui
  • Abstract:Waste recycling has,to some extent,a positive effect on solving resource and environmental crises;therefore,it has become an important measure of sustainable development.However,the resource depletion and pollution emissions involved in recycling and manufacturing processes also have negative impacts on nature.To solve this problem,we focused on the waste paper recycling system in order to build an ecological costs model based on material flow analysis,and to provide a basis for optimizing the waste recycling system.In this paper,we define the concepts of ecological costs and sum up the existing researches on these,and ensure that counting ecological costs based on material flow analysis is practical.Ecological costs are cause by resource consumption,waste emissions in the processes of recycling,manufacturing,etc.,and they are divided into the three categories:resource depletion,environmental pollution and protection,and ecological damage.Pollution yield and environmental protection costs are counted by allocating total manufacturing costs into positive and negative products,and then counting resource depletion and ecological damage costs using the LIME method.Total ecological costs in the recycling system are calculated by summing every ecological costs in the whole system.Although ecological cost accounting is an important means of evaluating the ecological load,the constitution of ecological costs for the waste paper system is depicted using the foundation of the material flow chart.The model we built is not only fit for the waste paper recycling system,but also valid for other waste products.In addition,this model counts the ecological costs and finds out the manufacturing progresses with high ecological impacts,thereby improving them and providing the basis for both environmental and economic benefits;thus,it constitutes an efficient waste recycling system.
  • DownLoad:Study on ecological costs for waste paper recycling system based on the Material Flow Analysis.PDF
  • Analysis and prediction of the atmospheric environmental capacity of the Xilinguole League's coal-based electricity region
  • Authors:MA Yiding, FU Xiao and WU Gang
  • Abstract:Coal-based electricity of the Xilinguole League area in Inner Mongolia is not only an important foundation for the country's economic development and energy security,but also an ecological protective screen nearby the capital.And the construction of coal-based energy infrastructure in this region directly affects its ecological security.In this study,the atmospheric pollutant emissions from coal-fired power plants Xilinguole League and its air quality were investigated,and the spatial distribution of the atmospheric environmental capacity was analyzed.The spatial distribution of major pollutants was mapped and combined with atmospheric quality standards to obtain the atmospheric environmental capacity.Based on these results for different scenarios (low,medium,or high standards),the predicted regional atmospheric environmental capacity was calculated,and the regional environmental protection countermeasures were analyzed.These results provide a scientific basis for the conservation and regional sustainable development of Xilinguole League.
  • DownLoad:Analysis and prediction of the atmospheric environmental capacity of the Xilinguole League's coal-based electricity region.PDF
  • Functional diversity of freshwater fishes and methods of measurement
  • Authors:SHUAI Fangmin, LI Xinhui, CHEN Fangcan, LI Yuefei, YANG Jiping, LI Jie and WU Zhi
  • Abstract:A key question in ecology is how biological diversity affects ecosystem functioning.This is of particular importance in the general context of human activities that have impacts on biodiversity,ecosystems,and their complex relationship.Currently,community functional diversity is receiving considerable academic attention,and is considered important in solving ecological problems.However,research has mostly focused on plant or microbial communities,and there has been almost no related research into fish communities.Although freshwater ecosystems represent only a very small part of the planet (<1% of Earth's surface),they support a disproportionally rich diversity of biological life and provide countless ecological services to humans (most notably to urban populations),including water purification,drinking water,food production,and leisure activities.For assemblages like reef fish communities,human disturbances such as fishing (i.e.the removal of target specimens) could reduce functional diversity and potentially have significant effects on ecosystem functioning.Fishery resources in China are declining because of many human-induced stressors such as overfishing,dam construction,and biological invasions,and aquatic ecosystem function has therefore undergone a serious decline.It has been suggested that the most appropriate way to fully understand and quantify the effects of natural-and human-induced perturbations on biodiversity is to apply functional approaches,as these incorporate the interactions between organisms and their surrounding environment.Functional diversity can be defined as the value,range,distribution,and ecological importance of organisms' functional attributes in a community.However,empirical assessments of the potential responses of freshwater functional diversity patterns to human-induced perturbations are still lacking.We reviewed the functional diversity of freshwater fish and methods of its calculation,including data acquisition and analysis,to provide a new theoretical basis for the protection of fish resources.Three independent indices have been proposed to quantify functional diversity of freshwater fishes:functional richness (FRic),functional evenness (FEve),and functional divergence (FDiv).These are based on the distribution of species and their abundance in a multidimensional Euclidean space (i.e.the so-called functional space) created using many functional traits of species.No clear criteria exist that define the most suitable index to investigate functional diversity.Increasing number of ecologists have been using a combination of several multi-trait indices to quantify functional diversity,since the use of complementary functional diversity indices can provide a better understanding of the role of biodiversity in ecosystem functioning.
  • DownLoad:Functional diversity of freshwater fishes and methods of measurement.PDF
  • Understanding the social and ecological connections between cities and surrounding regions for urban and regional sustainability
  • Authors:ZHOU Weiqi, WANG Kun, YU Wenjuan, LI Weifeng, HAN Lijian and QIAN Yuguo
  • Abstract:With the expansion of major cities and development of small towns (i.e.,regional urbanization),cities and their surrounding regions are increasingly facing serious problems,such as environmental pollution,ecological degradation,and resource shortages.This is particularly true in rapidly developing countries such as China.To solve these problems,it is crucially important to better understand the social and ecological connections between cities and their surrounding regions.This is because cities and their surrounding regions are integrated,socially and ecologically.On the one hand,urban sustainability can only be achieved with the support of the surrounding region.Conversely,urban sustainability plays a key role in region sustainability.This paper presents a comprehensive review on the social and ecological connections between cities and surrounding regions,with the goal of enhancing our understanding of the social and ecological linkages between cities and their surrounding regions.We reviewed literature,and loosely grouped studies into three categories:1) direct and indirect (e.g.,through social processes) effects of urban development on ecosystems and environments at urban and regional scales;2) ecosystem services provided by surrounding regions that support the development of cities;and 3) the social,economic,and ecological teleconnections and interactions between the city and its surrounding region.We further summarized and highlighted a few future directions that should be focused on to advance our understanding of the social and ecological connections between cities and regions:1) Most of the studies focused on the (adverse) impacts of urbanization (particularly urban land expansion) on surrounding regions.Few studies have considered the city and its surrounding regions as a coupled system and taken a holistic approach to examine their mutually supportive and interactive connections.Developing a holistic approach that considers the city and its surrounding regions as a coupled socio-ecological system will greatly enhance our understanding of the social and ecological connections between the two areas.2) Most of the previous studies focused on the social and economic linkages between cities and their surrounding regions,but ignored the ecological connections.Future research on the ecological linkages between cities and surrounding regions,and how the ecological linkages contribute to urban and regional sustainability is highly desirable.3) Currently,there are many new frameworks emerging that are potentially useful to understanding the linkages between cities and surrounding regions,such as the teleconnection/tele-coupling framework and the urban-rural continuum framework.However,quantitative approaches and models,as well as experimental case studies,are largely lacking,which warrants future research.
  • DownLoad:Understanding the social and ecological connections between cities and surrounding regions for urban and regional sustainability.PDF
  • Review of development,frontiers,and prospects of green infrastructure
  • Authors:LUAN Bo, CHAI Minwei and WANG Xin
  • Abstract:This paper first reviews the origin and development of green infrastructure (GI) and then summarizes the context,formation and development from the perspectives of human settlements,ecological protection,and green technology.Then,it describes GI from spatial,functional,and elemental aspects.The relationship of GI with ecological services is also elucidated.Through a literature review,the international research frontiers of GI are assessed for the following topics:climate change,human health,air quality,stormwater management,public awareness,community participation,and evaluation research.Finally,this paper predicts future developments in GI based on the current status of GI research and problems in China.
  • DownLoad:Review of development,frontiers,and prospects of green infrastructure.PDF

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