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New indices to balanceα-diversity against tree size inequality

Journal of Forestry Research 2024年第1期35卷 229-237页

作者： Li Zhang Brady K.Quinn Cang Hui Meng Lian Johan Gielis Jie Gao peijian shi College of Ecology and Environment Bamboo Research InstituteNanjing Forestry University159 Longpan RoadNanjing 210037People’s Republic of China Fisheries and Oceans Canada Andrews Biological Station125 Marine Science DriveSt.AndrewsNB E5B 0E4Canada Department of Mathematical Sciences Centre for Invasion BiologyStellenbosch UniversityMatieland 7602South Africa Mathematical and Physical Biosciences African Institute for Mathematical SciencesCape Town 7945South Africa Department of Biosciences Engineering University of AntwerpB-2020 AntwerpBelgium College of Life Science Xinjiang Normal University102 Xinyi RoadUrumqi 830054People’s Republic of China

The number and composition of species in a community can be quantified withα-diversity indices,including species richness(R),Simpson’s index(D),and the Shannon-Wiener index(H΄).In forest communities,there are large variations in tree size among species and individu-als of the same species,which result in differences in eco-logical processes and ecosystem functions.However,tree size inequality(TSI)has been largely neglected in studies using the available diversity indices.The TSI in the diameter at breast height(DBH)data for each of 99920 m×20 m forest census quadrats was quantified using the Gini index(GI),a measure of the inequality of size distribution.The generalized performance equation was used to describe the rotated and right-shifted Lorenz curve of the cumulative proportion of DBH and the cumulative proportion of number of trees per quadrat.We also examined the relationships ofα-diversity indices with the GI using correlation tests.The generalized performance equation effectively described the rotated and right-shifted Lorenz curve of DBH distributions,with most root-mean-square errors(990 out of 999 quadrats)being<0.0030.There were significant positive correlations between each of threeα-diversity indices(i.e.,R,D,and H’)and the GI.Nevertheless,the total abundance of trees in each quadrat did not significantly influence the GI.This means that the TSI increased with increasing spe-cies diversity.Thus,two new indices are proposed that can balanceα-diversity against the extent of TSI in the com-munity:(1−GI)×D,and(1−GI)×H’.These new indices were significantly correlated with the original D and H΄,and did not increase the extent of variation within each group of indices.This study presents a useful tool for quantifying both species diversity and the variation in tree sizes in forest communities,especially in the face of cumulative species loss under global climate change.

关键词： Diameter at breast height(DBH) Gini index Shannon-Wiener index Simpson’s index Quadrat Tree size

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An elliptical blade is not a true ellipse,but a superellipse–Evidence from two Michelia species

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Journal of Forestry Research 2022年第4期33卷 1341-1348页

作者： Yuping Li Karl JNiklas Johan Gielis Ülo Niinemets Julian Schrader Rong Wang peijian shi College of Horticulture Jinling Institute of TechnologyNanjing 210038People’s Republic of China Bamboo Research Institute Nanjing Forestry UniversityNanjing 210037People’s Republic of China Plant Biology Section School of Integrative Plant ScienceCornell UniversityIthacaNY 14853USA Department of Biosciences Engineering University of AntwerpB-2020 AntwerpBelgium Institute of Agricultural and Environmental Sciences Estonian University of Life Sciences51006 TartuEstonia Estonian Academy of Sciences 10130 TallinnEstonia Department of Biological Sciences Macquarie UniversitySydneyNSW 2109Australia Biodiversity Macroecology and BiogeographyUniversity of Göttingen37077 GöttingenGermany

The shape of leaf laminae exhibits considerable diversity and complexity that reflects adaptations to environmental factors such as ambient light and precipitation as well as phyletic legacy.Many leaves appear to be elliptical which may represent a‘default’developmental condition.However,whether their geometry truly conforms to the ellipse equation(EE),i.e.,(x/a)^(2)+(y/b)^(2)=1,remains conjectural.One alternative is described by the superellipse equation(SE),a generalized version of EE,i.e.,|x/a|^(n)+|y/b|^(n)=1.To test the efficacy of EE versus SE to describe leaf geometry,the leaf shapes of two Michelia species(i.e.,M.cavaleriei var.platypetala,and M.maudiae),were investigated using 60 leaves from each species.Analysis shows that the majority of leaves(118 out of 120)had adjusted root-mean-square errors of<0.05 for the nonlinear fitting of SE to leaf geometry,i.e.,the mean absolute deviation from the polar point to leaf marginal points was smaller than 5%of the radius of a hypothesized circle with its area equaling leaf area.The estimates of n for the two species were<2,indicating that all sampled leaves conformed to SE and not to EE.This study confirms the existence of SE in leaves,linking this to its potential functional advantages,particularly the possible influence of leaf shape on hydraulic conductance.

关键词： Bilateral symmetry Leaf ellipticalness index Leaf laminae Leaf roundness index Magnoliaceae

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Enhanced electrical,mechanical and tribological properties of Cu-Cr-Zr alloys by continuous extrusion forming and subsequent aging treatment

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Journal of Materials Science & Technology 2022年第15期110卷 187-197页

作者： Zhe Shen Zhongze Lin peijian shi Jiale Zhu Tianxiang Zheng Biao Ding Yifeng Guo Yunbo Zhong State Key Laboratory of Advanced Special Steel Shanghai UniversityShanghai 200444China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Shanghai Key Laboratory of Advanced Ferrometallurgy Shanghai UniversityShanghai 200444China

As a promising material for the new generation of high-speed railway contact wires,the comprehensive optimization of the electrical conductivity,strength,hardness and wear resistance of the Cu-Cr-Zr alloy has received extensive attention.In this paper,a high-performance Cu-1Cr-0.1Zr alloy with an ultimate tensile strength of 599.1 MPa,a uniform elongation of 8.6%,a microhardness of 195.7 HV_(0.2) and an electrical conductivity of 80.07%IACS was achieved by the continuous extrusion forming(CEF)and subsequent peak-aging treatment.The grain refinement strengthening,dislocation strengthening and precipitation strengthening are identified to be responsible for the excellent electrical and mechanical properties of Cu-Cr-Zr alloy.The wear behavior of Cu-Cr-Zr alloy was investigated by examining the evolution of worn surface morphology and subsurface microstructure.The microhardness(H)and reduced elastic modulus(E_(r))of the subsurface below the worn surface measured by nanoindentation were calculated to gage the tribological performance of Cu-Cr-Zr alloy.Results show that the continuously extruded and subsequently peak-aged specimen has the best wear resistance,which indicates that the tribological properties of CuCr-Zr alloy strongly depend on its strength and hardness.It can be concluded that the CEF and subsequent aging treatment process provides a new and high-efficiency procedure for the continuous preparation of Cu-Cr-Zr alloys.

关键词： Cu-Cr-Zr alloy Continuous extrusion Electrical conductivity Mechanical properties Tribological properties

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Seed handling by primary frugivores differentially influence post-dispersal seed removal of Chinese yew by ground-dwelling animals

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Integrative Zoology 2016年第3期11卷 191-198页

作者： Yang PAN Bing BAI Tianshi XIONG peijian shi Changhu LU Laboratory of Plant-Animal Interactions Nanjing Forestry UniversityNanjingChina Yunnan Forestry Technological College KunmingChina Bamboo Research Institute Nanjing Forestry UniversityNanjingChina

Seed handling by primary frugivores can influence secondary dispersal and/or predation of post-dispersal seeds by attracting different guilds of ground-dwelling animals.Many studies have focused on seeds embedded in feces of mammals or birds;however,less is known about how ground-dwelling animals treat seeds regurgitated by birds(without pulp and not embedded in feces).To compare the effect of differential seed handling by primary dispersers on secondary seed removal of Chinese yew(Taxus chinensis var.mairei),we conducted a series of exclosure experiments to determine the relative impact of animals on the removal of defecated seeds(handled by masked palm civet),regurgitated seeds(handled by birds)and intact fruits.All types of yew seeds were consistently removed at a higher rate by rodents than by ants.Regurgitated seeds had the highest removal percentage and were only removed by rodents.These seeds were probably eaten in situ without being secondarily dispersed.Defecated seeds were removed by both rodents and ants;only ants might act as secondary dispersers of defecated seeds,whereas rodents ate most of them.We inferred that seeds regurgitated by birds were subjected to the highest rates of predation,whereas those dispersed in the feces of masked palm civets probably had a higher likelihood of secondary dispersal.Seeds from feces attracted ants,which were likely to transport seeds and potentially provided a means by which the seeds could escape predation by rodents.Our study highlighted that primary dispersal by birds might not always facilitate secondary dispersal and establishment of plant populations.

关键词： arils defecated seeds regurgitated seeds secondary seed dispersal Taxus chinensis

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Quantifyingα-diversity as a continuous function of location——a case study of a temperate forest

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林业研究:英文版 2023年第6期34卷 1683-1691页

作者： peijian shi Brady K.Quinn Long Chen Jie Gao Julian Schrader Bamboo Research Institute College of Ecology and EnvironmentNanjing Forestry University159 Longpan RoadNanjing 210037People’s Republic of China Tropical Silviculture and Forest Ecology University of GottingenBusgenweg 137077 GottingenGermany St.Andrews Biological Station Fisheries and Oceans Canada125 Marine Science DriveSt.AndrewsNB E5B 0E4Canada College of Life Science Xinjiang Normal University102 Xinyi RoadUrumqi 830054People’s Republic of China School of Natural Sciences Macquarie UniversitySydneyNSW 2109Australia Biodiversity Macroecology&BiogeographyUniversity of GottingenBusgenweg 137077 GottingenGermany

α-diversity describes species diversity at local scales.The Simpson’s and Shannon-Wiener indices are widely used to characterizeα-diversity based on species abundances within a fixed study site(e.g.,a quadrat or plot).Although such indices provide overall diversity estimates that can be analyzed,their values are not spatially continuous nor applicable in theory to any point within the study region,and thus they cannot be treated as spatial covariates for analyses of other variables.Herein,we extended the Simpson’s and Shannon-Wiener indices to create point estimates ofα-diversity for any location based on spatially explicit species occurrences within different bandwidths(i.e.,radii,with the location of interest as the center).For an arbitrary point in the study region,species occurrences within the circle plotting the bandwidth were weighted according to their distance from the center using a tri-cube kernel function,with occurrences closer to the center having greater weight than more distant ones.These novel kernel-basedα-diversity indices were tested using a tree dataset from a 400 m×400 m study region comprising a 200 m×200 m core region surrounded by a 100-m width buffer zone.Our newly extendedα-diversity indices did not disagree qualitatively with the traditional indices,and the former were slightly lower than the latter by<2%at medium and large band widths.The present work demonstrates the feasibility of using kernel-basedα-diversity indices to estimate diversity at any location in the study region and allows them to be used as quantifiable spatial covariates or predictors for other dependent variables of interest in future ecological studies.Spatially continuousα-diversity indices are useful to compare and monitor species trends in space and time,which is valuable for conservation practitioners.

关键词： Distance-based weighting Diversity continuum Kernel function Shannon-Wiener index Simpson’s index Tri-cube kernel

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Spatio-temporal point pattern analysis on Wenchuan strong earthquake

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Earthquake Science 2009年第3期22卷 231-237页

作者： peijian shi Jie Liu Zhen Yang Agricultural College JiangxiAgricultural University Nanehang 330045 China China Earthquake Networks Center Beij'ing 100036 China Department of Precision Instrument andMechanology Tsingkua University Beijing 100084 China

For exploring the aftershock occurrence process of the 2008 Wenchuan strong earthquake, the spatio-temporal point pattern analysis method is employed to study the sequences of aflershocks with magnitude M≥4.0, M≥4.5, and M≥5.0. It is found that these data exhibit the spatio-temporal clustering on a certain distance scale and on a certain time scale. In particular, the space-time interaction obviously strengthens when the distance is less than 60 km and the time is less than 260 h for the first two aftershock sequences; however, it becomes strong when the distance scale is less than 80 km and the time scale is less than 150 h for the last aftershock sequence. The completely spatial randomness analysis on the data regardless of time component shows that the spatial clustering of the aftershocks gradually strengthens on the condition that the distance is less than 60 km. The results are valuable for exploring the occurrence rules of the Wenchuan strong earthquake and for predicting the aftershocks.

关键词： Wenchuan earthquake completely spatial randomness spatio-temporal point pattern K-function

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Comparison of seed morphology of two ginkgo cultivars

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Journal of Forestry Research 2020年第3期31卷 751-758页

作者： Fang Tian Yujun Wang Hardev S.Sandhu Johan Gielis peijian shi Co-Innovation Centre for Sustainable Forestry in Southern China Nanjing Forestry UniversityNanjing 210037JiangsuPeople’s Republic of China Everglades Research and Education Center University of Florida3200 E.Palm Beach RoadBelle GladeFL 33430USA Department of Biosciences Engineering University of Antwerp2020 AntwerpBelgium

Ginkgo biloba L. is a precious relic tree species with important economic value. Seeds, as a vital reproductive organ of plants, can be used to distinguish cultivars of the species. We chose 400 seeds from two cultivars of ginkgo(“Fozhi” and “Maling”;200 seeds for each cultivar) as the study material and used the Gielis equation to fit the projected shape of these seeds. The coefficients of variation(CV) in root mean squared errors(RMSE)obtained from the fitted data were used to compare the level of inter-cultivar variations in seed shape. We also used the covariance analysis to compare the allometric relationships between seed weights and projected areas of these two cultivars. The Gielis equation fitted well the seedshapes of two ginkgo cultivars. The lower CV in RMSE of cultivar “Fozhi” than “Maling” indicated a less symmetrical seed shape in the latter than the former. The bootstrap percentile method showed that the seed shape differences between the two cultivars were significant. However, there was no significant difference in the exponents between the seed weights and the projected areas of these two cultivars.Overall, the significant differences in shapes between the seeds of two ginkgo cultivars were well explained by the Gielis equation;this model can be further extended to compare morphological differences in other ginkgo cultivars, and even for plant seeds or animal eggs that have similar oval shapes.

关键词： Allometry Coefficient of variation Curve fitting Gielis equation Root mean squared errors

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Variation in individual biomass decreases faster than mean biomass with increasing density of bamboo stands

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Journal of Forestry Research 2020年第3期31卷 981-987页

作者： Guohua Liu Cang Hui Ming Chen Lauren SPile GGeoff Wang Fusheng Wang peijian shi Co-Innovation Centre for Sustainable Forestry in Southern China Bamboo Research InstituteNanjing Forestry UniversityNanjing 210037People’s Republic of China Department of Mathematical Sciences Centre for Invasion BiologyStellenbosch UniversityMatieland 7602South Africa Mathematical and Physical Biosciences African Institute for Mathematical SciencesCape Town 7945South Africa USDA Forest Service Sierra National Forest—High Sierra Ranger DistrictPratherCA 93651USA Department Forestry and Environmental Conservation Clemson UniversityClemsonSC 29634USA

The total biomass of a stand is an indicator of stand productivity and is closely related to the density of plants. According to the self-thinning law, mean individual biomass follows a negative power law with plant density. If the variance of individual biomass is constant, we can expect increased stand productivity with increasing plant density. However, Taylor's power law(TPL) that relates the variance and the mean of many biological measures(e.g. bilateral areal differences of a leaf, plant biomass atdifferent times, developmental rates at different temperatures, population densities on different spatial or temporal scales), affects the estimate of stand productivity when it is defined as the total biomass of large plants in a stand.Because the variance of individual biomass decreases faster than mean individual biomass, differences in individual biomass decline with increasing density, leading to more homogeneous timbers of greater economic value. We tested whether TPL in plant biomass holds for different species and whether the variance of individual biomass changes faster than the mean with increasing stand density.The height, ground diameter and fresh weight of 50 bamboo species were measured in 50 stands ranging from 1 m by 1 m to 30 m by 30 m to ensure more than 150 bamboos in every stand. We separately examined TPL in height,ground diameter, and weight, and found that TPL holds for all three biological measures, with the relationship strongest for weight. Using analysis of covariance to compare the regression slopes of logarithmic mean and variance against the logarithm of density, we found that the variance in individual biomass declined faster than the mean with increasing density. This suggests that dense planting reduced mean individual biomass but homogenized individual biomass. Thus, there exists a trade-off between effective stand productivity and stand density for optimal forest management. Sparse planting leads to large variation in individual biomass, whereas dense planting reduces mean indiv

关键词： Bamboo Linear fitting Self-thinning law Taylor's power law Variance

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A precipitate-free AlCoFeNi eutectic high-entropy alloy with strong strain hardening

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Journal of Materials Science & Technology 2021年第30期89卷 88-96页

作者： peijian shi Yi Li Yuebo Wen Yiqi Li Yan Wang Weili Ren Tianxiang Zheng Yifeng Guo Long Hou Zhe Shen Ying Jiang Jianchao Peng Pengfei Hu Ningning Liang Qingdong Liu Peter K.Liaw Yunbo Zhong State Key Laboratory of Advanced Special Steel&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai200444China Materials Genome Institute Shanghai UniversityShanghai200444China Laboratory for Microstructures Shanghai UniversityShanghai200444China School of Materials Science and Engineering Nanjing University of Science and TechnologyJiangsu210094China Institute of Materials Modification and Modelling School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN37996USA

Over recent years,eutectic high-entropy alloys(EHEAs)have intrigued substantial research enthusiasms due to their good castability as well as balanced strength-ductility synergy.In this study,a bulk cast Al_(19.25)Co_(18.86)Fe_(18.36)Ni_(43.53)EHEA is developed with fine in-situ lamellar eutectics.The eutectics comprise alternating ordered face-centered-cubic(L1_(2))and ordered body-centered-cubic(B2)phases with semicoherent interfaces.The resulting microstructure resembles that of most reported as-cast EHEAs,but the B2 lamellae are devoid of nano-precipitates because of the Cr-element removal in current tailored eutectic composition.Surprisingly,the B2 lamellae still feature much higher deformation resistance than the L1_(2) lamellae,so that less lattice defects are detected in the B2 lamellae until the fracture.More interestingly,in the L1_(2) lamellae we identify a dynamic microstructure refinement that correlates to extraordinary strain hardening in tension.The precipitate-free EHEA consequently shows excellent tensile ductility of~10%and high ultimate strength up to~956 MPa.

关键词： High-entropy alloy Lamellar eutectic Deformation resistance Microstructure refinement Strain hardening

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Cascade effects of crop species richness on the diversity of pest insects and their natural enemies

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Science China(Life Sciences) 2014年第7期57卷 718-725页

作者： shi peijian HUI Cang MEN XingYuan ZHAO ZiHua OUYANG Fang GE Feng JIN Xianshi CAO HaiFeng LI B.Larry State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture Institute of ZoologyChinese Academy of Sciences Key Laboratory of Sustainable Development of Marine Fisheries Ministry of AgricultureYellow Sea Fisheries Research InstituteChinese Academy of Fishery Sciences Centre for Invasion Biology Department of Botany and ZoologyStellenbosch University Institute of Plant Protection Shandong Academy of Agricultural Sciences Ecological Complexity and Modeling Laboratory University of California

Understanding how plant species richness influences the diversity of herbivorous and predatory/parasitic arthropods is central to community ecology.We explore the effects of crop species richness on the diversity of pest insects and their natural enemies.Using data from a four-year experiment with five levels of crop species richness,we found that crop species richness significantly affected the pest species richness,but there were no significant effects on richness of the pests’natural enemies.In contrast,the species richness of pest insects significantly affected their natural enemies.These findings suggest a cascade effect where trophic interactions are strong between adjacent trophic levels,while the interactions between connected but nonadjacent trophic levels are weakened by the intermediate trophic level.High crop species richness resulted in a more stable arthropod community compared with communities in monoculture crops.Our results highlight the complicated cross-trophic interactions and the crucial role of crop diversity in the food webs of agro-ecosystems.

关键词：农作物品种物种丰富度作物多样性害虫天敌级联效应节肢动物群落农业生态系统相互作用

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