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Functional leaf and size traits determine the photosynthetic response of 10 dryland species to warming

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Journal of Plant Ecology 2016年第6期9卷 773-783页

作者： Enrique Valencia JoséL.Quero Fernando T.Maestre Departamento de Biología y Geología Física y Química InorgánicaEscuela Superior de Ciencias Experimentales y TecnologíaUniversidad Rey Juan CarlosC/Tulipán s/n28933 MóstolesSpain Departamento de Ingeniería Forestal Escuela Técnica Superior de Ingeniería Agronómica y de MontesUniversidad de Córdoba Campus de Rabanales CrtaN-IV km.396C.P.14071 CórdobaSpain

Aims Relatively few studies so far have assessed how ongoing global warming will affect the photosynthetic performance of dryland plant species.We evaluated the effects of warming on the photosynthetic rates of 10 species with contrasting functional attributes,and whether their functional traits modulated photosynthetic responses to warming.Methods A common garden experiment was conducted over 2 years with distinct environmental conditions(drier vs.wetter year).the experiment was designed as a randomized block design with two treatments:warming(control vs.~2.9℃ temperature increase)and species(Agropyron cristatum,Festuca ovina,Lygeum spartum,Medicago sativa,Plantago lanceolata,Psoralea bituminosa,Sanguisorba minor,Hedysarum coronarium,Dorycnium pentaphyllum and Phlomis herba-venti).We linked functional traits measurements with temporal variations in photosynthetic responses to warming.Important Findings In the drier year,warming increased photosynthetic rates at the beginning of the growing season,suggesting a modification in the growing period(earlier spring).In the wetter year,functional traits modulated photosynthetic responses to warming.Larger species with shorter leaves(e.g.M.sativa)had higher photosynthetic rates under warming compared to smaller species with larger leaves(e.g.F.ovina).Our results highlight the importance of(i)studying photosynthetic responses along different years and(ii)considering functional traits when evaluating photosynthetic responses to climate change,particularly in stressful environments such as drylands.

关键词： photosynthesis climate change Mediterranean functional traits open top chambers

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干旱区主导全球植被生产力增加趋势

Science Bulletin 2023年第2期68卷 224-232,M0004页

作者：王帅傅伯杰魏芳莉朴世龙 Fernando T.Maestre Lixin Wang Wenzhe Jiao 刘焱序李琰李长嘉赵文武 State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100871China Department of Ecology University of AlicanteCarretera de San Vicente del RaspeigAlicante 03690Spain Multidisciplinary Institute for Environment Studies“Ramon Margalef” University of AlicanteCarretera de San Vicente del RaspeigAlicante 03690Spain Department of Earth Sciences Indiana University-Purdue University IndianapolisIndianapolis IN 46202USA

旱区(drylands)是指年平均降雨量与潜在蒸散发之比小于0.65的区域,占全球陆地表面的42%,是最易受气候变化影响的地区之一.然而,目前关于旱区植被对气候变化的响应特征及其对全球变绿和陆地生态系统生产力变化的相对贡献仍不清楚.本研究... 详细信息

旱区(drylands)是指年平均降雨量与潜在蒸散发之比小于0.65的区域,占全球陆地表面的42%,是最易受气候变化影响的地区之一.然而,目前关于旱区植被对气候变化的响应特征及其对全球变绿和陆地生态系统生产力变化的相对贡献仍不清楚.本研究通过集成模型和遥感数据分析发现,旱区对全球变绿的贡献较小,仅占33%±15%,但却主导了全球植被生产力(GPP)增加趋势,贡献达65%±16%旱区植被光合利用效率升高是解释变绿与生产力增加不一致的主要原因.旱区光能利用率主要受土壤水分的影响,大气水汽压差作用不显著,而非旱区主要受大气水汽压差的影响,土壤水的作用有限.因此,需要强调使用不同的水分胁迫指标来预测不同区域植被生产力变化的重要性,这也有助于理解较长时间尺度上植被绿度与生产力之间的解耦关系.

关键词：光能利用率水汽压差气候变化影响植被生产力旱区潜在蒸散发相对贡献集成模型

Stipa tenacissima Does not Affect the Foliar δ^(13)C and δ^(15)N of Introduced Shrub Seedlings in a Mediterranean Semi-arid Steppe

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Journal of Integrative Plant Biology 2006年第8期48卷 897-905页

作者： Fernando T.Maestre Susana Bautista Jordi Cortina Departamento de Ecologia Universidad de AlicanteApartado de correos 9903080 AlicanteSpain Department of Biology Duke UniversityPhytotron BuildingScience DriveBox 90340DurhamNorth Carolina 27708-0340USA Centro de Estudios Ambientales del Mediterraneo C/ Charles Darwin 1446980 PaternaSpain

Recent studies have shown that the tussock grass Stipa tenacissima L. facilitates the establishment of late-successional shrubs, in what constitutes the first documented case of facilitation of woody plants by grasses. With the aim of increasing our knowledge of this interaction, in the present study we investigated the effects of S. tenacissima on the foliar δ13C, δ15N, nitrogen concentration, and carbon ： nitrogen ratio of introduced seedlings of Pistacia lentiscus L., Quercus coccifera L., and Medicago arborea L. in a semi-arid Mediterranean steppe. Six months after planting, the values of δ13C ranged between -26.9‰ and -29.6‰, whereas those of δ15N ranged between -1.9‰ and 2.7‰. the foliar C ： N ratio ranged between 10.7 and 53.5, and the nitrogen concentration ranged between 1.0% and 4.4%. We found no significant effect of the microsite provided by S. tenacissima on these variables in any of the species evaluated. the values of δ13C were negatively correlated with predawn water potentials in M. arborea and were positively correlated with relative growth rate in Q. coccifera. the values of δ15N were positively correlated with the biomass allocation to roots in the latter species. the present results suggest that the modification of environmental conditions in the are surrounding S. tenacissima was not strong enough to modify the foliar isotopic and nitrogen concentration of shrubs during the early stages after planting.

关键词： facilitation Medicago arborea Pistacia lentiscus Quercus coccifera stable isotopes steppe Stipa tenacissima.

Variation in the methods leads to variation in the interpretation of biodiversity-ecosystem multifunctionality relationships

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Journal of Plant Ecology 2020年第4期13卷 431-441页

作者： Xin Jing Case M.Prager Aimée t.Classen Fernando T.Maestre Jin-Sheng He Nathan J.Sanders Rubenstein School of Environment and Natural Resources University of VermontBurlingtonVT 05405USA Gund Institute for Environment University of VermontBurlingtonVT 05405USA Center for Macroecology Evolutionand ClimateNatural History Museum of DenmarkCopenhagenDenmark Departamento de Biología GeologíaFísica y Química InorgánicaEscuela Superior de Ciencias Experimentales y TecnologíaUniversidad Rey Juan CarlosMóstoles 28933Spain Departamento de Ecología and Instituto Multidisciplinar para el Estudio del Medio“Ramon Margalef” Universidad de AlicanteAlicanteSpain Department of Ecology College of Urban and Environmental SciencesPeking UniversityBeijingChina Environmental Program Rubenstein School of Environment and Natural ResourcesUniversity of VermontBurlingtonVT 05405USA Present address:Department of Earth and Environmental Sciences KU LeuvenCelestijnenlaan 200E3001 LeuvenBelgium

生物多样性常常和生态系统多功能性(生态系统同时提供多个生态系统功能的能力)正相关。然而,生物多样性与生态系统多功能性的关系是否依赖于生态系统功能的数目有诸多争议。其中,生物多样性对生态系统多功能性的影响或许不随生态系统功... 详细信息

生物多样性常常和生态系统多功能性(生态系统同时提供多个生态系统功能的能力)正相关。然而,生物多样性与生态系统多功能性的关系是否依赖于生态系统功能的数目有诸多争议。其中,生物多样性对生态系统多功能性的影响或许不随生态系统功能数目的变化而变化,或者随生态系统功能数目的增多而增强。我们期望通过研究不同生态系统多功能性指数的统计原理来解决这些争议。我们使用了模型模拟和一系列来自不同空间尺度(从局域到全球)和不同生物群系(温带和高寒草地、森林和干旱地)的经验数据。我们回顾了量化生态系统多功能性的三种方法,包括平均值法、加和法和阈值法。我们发现随着生态系统功能数目的增加,生物多样性与生态系统多功能性的关系要么不变,要么增强。这些结果可由平均和加和的多功能性指数的统计原理来解释。具体来讲,当利用生态系统功能的平均值计算多功能性指数时,由于多样性对多功能性的效应等于多样性对单个生态系统功能效应的平均值,所以不会随生态系统功能数目的变化而变化。同样的道理,当利用单个生态系统的加和值计算多功能性指数时,多样性的效应会随着生态系统功能数目的增加而增强。我们提出了一个改进的多功能性指数,将平均或加和多功能性指数转化为标准化的多功能性指数,以便于对不同研究的结果进行比较。此外,我们提出了基于变量数值范围的标准化方法来解决阈值法的数学假象问题(多样性效应随生态系统功能数目的增加而增强)。我们的研究结果表明,量化多功能性指数的方法不同,结果也不同。因此,有必要加深对不同方法数理基础的理解。而标准化的多功能性指数为比较不同研究中的生物多样性与生态系统多功能性的关系提供了有效的方法。

关键词：平均值法生物多样性生态系统多功能性多阈值法植物物种丰富度空间尺度

土壤水分胁迫制约全球植被变绿和初级生产力持续增加

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Science Bulletin 2021年第14期66卷 1462-1471,M0004页

作者：冯晓明傅伯杰张园潘乃青曾振中田汉勤吕一河陈永喆 Philippe Ciais 王应平张橹程磊 Fernando T.Maestre Marcos Fernández-Martínez Jordi Sardans Josep Peñuelas State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China International Center for Climate and Global Change Research School of Forestry and Wildlife SciencesAuburn UniversityAuburnAL 36832USA School of Environmental Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Laboratoire des Sciences du Climat et de l’Environnement CEA CNRS UVSQGif-sur-Yvette 91191France Oceans and Atmosphere Commonwealth Scientific and Industrial Research OrganisationAspendaleVictoria 3195Australia South China Botanic Garden Chinese Academy of SciencesGuangzhou 510650China Land and Water Commonwealth Scientific and Industrial Research OrganisationBlack MountainCanberraACT 2601Australia School of Water Resources and Hydropower Engineering Wuhan UniversityWuhan 430072China Departamento de Ecología and Instituto Multidisciplinar para el Estudio del Medio“Ramon Margalef” Universidad de AlicanteAlicante 03690Spain Global Ecology Unit CREAF-CEAB-UAB Spanish National Research CouncilCerdanyola del VallèsCatalonia 08193Spain

大尺度的研究表明全球植被光合能力和生产力自20世纪80年代以来持续增加,但是很少有研究关注到其时空异质性.本研究将全球植被绿度变化趋势分为持续变绿、由变绿转为变棕、持续变棕以及不显著变化等不同类型,发现全球植被绿度变棕区域... 详细信息

大尺度的研究表明全球植被光合能力和生产力自20世纪80年代以来持续增加,但是很少有研究关注到其时空异质性.本研究将全球植被绿度变化趋势分为持续变绿、由变绿转为变棕、持续变棕以及不显著变化等不同类型,发现全球植被绿度变棕区域持续增加.到2010年以后逐渐超过持续变绿的区域(27.8×10^(6)km^(2),26.4%),达到了39.0×10^(6)km^(2)(全球植被面积的35.9%).这一现象抵消了2010年前12.0%±3.1%(0.019±0.004 NDVI a^(-1))植被绿度增加(2010~2016,P<0.05).全球陆地生态系统初级生产力也表现为类似的变化特征.这种变化主要是由于土壤水对于植被胁迫的负向作用,在部分地区超过了温度和辐射对于植被光合的积极作用.目前地球系统模型中的相关模块并不能反映这一正在增加的植被土壤水分胁迫.研究提示随着全球升温作用进一步加强,目前的地球系统模型土地模块可能会高估全球陆地生态系统碳固持能力.

关键词：初级生产力土壤水分胁迫时空异质性陆地生态系统全球升温 ). 植被绿度系统模型

Slope reliability and back analysis of failure with geotechnical parameters estimated using Bayesian inference

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 628-643页

作者： Luis-fernando Contreras Edwin t.Brown the University of Queensland St Lucia Campus

A Bayesian approach is proposed for the inference of the geotechnical parameters used in slope design.the methodology involves the construction of posterior probability distributions that combine prior information on the parameter values with typical data from laboratory tests and site investigations used in design.the posterior distributions are often complex,multidimensional functions whose analysis requires the use of Markov chain Monte Carlo(MCMC)methods.these procedures are used to draw representative samples of the parameters investigated,providing information on their best estimate values,variability and correlations.the paper describes the methodology to define the posterior distributions of the input parameters for slope design and the use of these results for evaluation of the reliability of a slope with the first order reliability method(FORM).the reliability analysis corresponds to a forward stability analysis of the slope where the factor of safety(FS)is calculated with a surrogate model from the more likely values of the input parameters.the Bayesian model is also used to update the estimation of the input parameters based on the back analysis of slope failure.In this case,the condition FS?1 is treated as a data point that is compared with the model prediction of FS.the analysis requires a sufficient number of observations of failure to outbalance the effect of the initial input parameters.the parameters are updated according to their uncertainty,which is determined by the amount of data supporting them.the methodology is illustrated with an example of a rock slope characterised with a Hoek-Brown rock mass strength.the example is used to highlight the advantages of using Bayesian methods for the slope reliability analysis and to show the effects of data support on the results of the updating process from back analysis of failure.

关键词： Bayesian analysis Hoek-Brown criterion Slope reliability Back analysis of failure

Bayesian data analysis to quantify the uncertainty of intact rock strength

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第1期10卷 11-31页

作者： Luis fernando Contreras Edwin t.Brown Marc Ruest the University of Queensland St Lucia CampusBrisbaneQLD 4072Australia Golder Associates Pty.Ltd. BrisbaneAustralia

One of the main difficulties in the geotechnical design process lies in dealing with uncertainty. Uncertainty is associated with natural variation of properties, and the imprecision and unpredictability caused by insufficient information on parameters or models. Probabilistic methods are normally used to quantify uncertainty. However, the frequentist approach commonly used for this purpose has some drawbacks.First, it lacks a formal framework for incorporating knowledge not represented by data. Second, it has limitations in providing a proper measure of the confidence of parameters inferred from data. the Bayesian approach offers a better framework for treating uncertainty in geotechnical design. the advantages of the Bayesian approach for uncertainty quantification are highlighted in this paper with the Bayesian regression analysis of laboratory test data to infer the intact rock strength parameters σand mused in the Hoek-Brown strength criterion. two case examples are used to illustrate different aspects of the Bayesian methodology and to contrast the approach with a frequentist approach represented by the nonlinear least squares(NLLS) method. the paper discusses the use of a Student’s t-distribution versus a normal distribution to handle outliers, the consideration of absolute versus relative residuals, and the comparison of quality of fitting results based on standard errors and Bayes factors. Uncertainty quantification with confidence and prediction intervals of the frequentist approach is compared with that based on scatter plots and bands of fitted envelopes of the Bayesian approach. Finally, the Bayesian method is extended to consider two improvements of the fitting analysis. the first is the case in which the Hoek-Brown parameter, a, is treated as a variable to improve the fitting in the triaxial region. the second is the incorporation of the uncertainty in the estimation of the direct tensile strength from Brazilian test results within the overall evaluation of the intact rock strength.

关键词： Uncertainty Intact rock strength Bayesian analysis Hoek-Brown criterion

基于神经网络和光流场的嵌入式高速目标识别与跟踪（英文）

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中国公路学报 2015年第11期28卷 112-123页

作者：苏金泷 HERBERt H C IU fernando t 西澳大学电气与电子工程学院泉州师范学院陈守仁工商信息学院福建泉州362000

研究了面向嵌入式硬件平台的高速视频图像处理与高速目标跟踪算法。基于神经网络的光流场算法能有效减少程序对硬件系统的内存要求和运算要求,该算法能够比传统算法更加容易的应用于以DSP(数字信号处理)芯片为核心的嵌入式硬件平台中。... 详细信息

研究了面向嵌入式硬件平台的高速视频图像处理与高速目标跟踪算法。基于神经网络的光流场算法能有效减少程序对硬件系统的内存要求和运算要求,该算法能够比传统算法更加容易的应用于以DSP(数字信号处理)芯片为核心的嵌入式硬件平台中。首先设计了一个基于Hopfield神经网络控制器的自适应滤波器,以图像信噪比为控制指标,对需进行目标识别的视频图像进行图像预处理;然后,利用补偿模糊神经网络控制器对光流场计算方法进行优化,这是一种通过参数控制平滑度实现的平均速度的角度误差和标准角误差的CFNN(补偿模糊神经网络)控制器识别跟踪算法。微机仿真及嵌入式系统试验结果均表明:该算法能够在同等条件下显著提高目标辨别与跟踪能力,显示其具有较高的有效性和实用性。

关键词：交通工程图像去噪补偿模糊神经网络光流场目标识别

A Simpler Memristor Emulator Based on Varactor Diode

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Chinese Physics Letters 2018年第5期35卷 144-147页

作者：于东升孙婷婷郑辞晏 H.H.C.Iu t.fernando School of Electrical and Power Engineering China University of Mining and Technology School of Electrical Electronic and Computer Engineering The University of Western Australia

A new memristor（MR） emulator is designed by making use of only three current-feedback operational amplifiers,one varactor diode, one capacitor and five resistors. As compared with other reported MR emulators, only three active devices and ten components in total are required for realizing this MR emulator, and hence this emulator can be regarded as a simpler one for the moment. the results obtained by Multisim simulation and experimental prototypes are given to verify the practicality and feasibility of this MR emulator.

关键词： MR As