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| 1 | Global leaf nitrogen and phosphorus stoichiometry and their scaling exponent显示文摘Leaf nitrogen(N) and phosphorus(P) concentrations constrain photosynthetic and metabolic processes,growth and the productivity of plants. Their stoichiometry and scaling relationships regulate the allocation of N and P from subcellular to organism, and even ecosystem levels, and are crucial to the modelling of plant growth and nutrient cycles in terrestrial ecosystems. Prior work has revealed a general biogeographic pattern of leaf N and P stoichiometric relationships and shown that leaf N scales roughly as two-thirds the power of P. However, determining whether and how leaf N and P stoichiometries, especially their scaling exponents, change with functional groups and environmental conditions requires further verification. In this study, we compiled a global data set and documented the global leaf N and P concentrations and the N:P ratios by functional group, climate zone and continent. The global overall mean leaf N and P concentrations were 18.9 mg g^(-1) and 1.2 mg g^(-1), respectively, with significantly higher concentrations in herbaceous than woody plants(21.72 mg g^(-1) vs. 18.22 mg g^(-1) for N; and 1.64 mg g^(-1) vs. 1.10 mg g^(-1) for P). Both leaf N and P showed higher concentrations at high latitudes than low latitudes. Among six continents, Europe had the highest N and P concentrations(20.79 and 1.54 mg g^(-1)) and Oceania had the smallest values(10.01 and 0.46 mg g^(-1)). These numerical values may be used as a basis for the comparison of other individual studies. Further, we found that the scaling exponent varied significantly across different functional groups,latitudinal zones, ecoregions and sites. The exponents of herbaceous and woody plants were 0.659 and0.705, respectively, with significant latitudinal patterns decreasing from tropical to temperate to boreal zones. At sites with a sample size ≥10, the values fluctuated from 0.366 to 1.928, with an average of 0.841.Several factors including the intrinsic attributes of different life forms, P-related growth rates and relative nutrient availability of soils likely account for the inconstant exponents of leaf N vs. P scaling relationships. | Di Tian Zhengbing Yan Karl J.Niklas Wenxuan Han Jens Kattge Peter B.Reich Yongkai Luo Yahan Chen Zhiyao Tang Huifeng Hu Ian J.Wright Bernhard Schmid Jingyun Fang | 2018 | National Science Review2018，5，5： | 24 |
| 2 | Canopy gap size influences niche partitioning of the ground-layer plant community in a northern temperate forest显示文摘Aims The Gap Partitioning Hypothesis(GPH)posits that gaps create heterogeneity in resources crucial for tree regeneration in closed-canopy forests,allowing trees with contrasting strategies to coexist along resource gradients.Few studies have examined gap partitioning of temperate,ground-layer vascular plants.We used a ground-layer plant community of a temperate deciduous forest in northern Wisconsin,USA,as a model system to test whether the GPH extends to the relatively species-rich ground layer.Methods We used a well-replicated experimental approach that included a gap opening gradient(five gap sizes,6,10,20,30 and 46 m diameter,and undisturbed reference areas),a within-gap location gradient(gap edge to center),and a temporal gradient(0,2,6 and 13 years after gap creation).The data were observations of ground-layer plant abundance,published plant traits,and a modeled index of understory light environments.We ordinated the plant abundance data and evaluated the relationships of composition,traits and light environment by gap size,location along the forest-gap transect and time,with several approaches such as correlations,descriptive statistics,non-parametric tests of group differences and indicator species importance values.Important Findings Ground-layer plant composition and traits differed across gap sizes,within-gap locations and over time.Gaps of all sizes differed in composition from undisturbed areas,and all pair-wise combinations of gap size also differed in composition,except the 6 m from the 10-m gaps.Large gaps(46 m)also displayed within-gap compositional gradients from gap edge to center locations.Compositional differences in gap size were evident 2 years after gap creation and,contrary to our hypotheses,remained different over the 13-year period,even in gaps with crown closure.In contrast to the neutral theory,species functional traits and microenvironmental conditions were related to variation in ground-layer composition.Species with smaller seeds,lower shade tolerance,later bloom times,shorter stature and longer leaves were associated with higher light,more central gap locations,larger gap sizes and greater time since gap creation.The correlation between gap size and ground-layer plant composition and traits provides evidence for gap partitioning by the diverse ground-layer community in this temperate deciduous forest community. | Christel C.Kern Rebecca A.Montgomery Peter B.Reich Terry F.Strong | 2013 | Journal of Plant Ecology2013，6，1： | 6 |
| 3 | Community phylogenetic diversity and abiotic site characteristics influence abundance of the invasive plant Rhamnus cathartica L.显示文摘Aims Theory predicts that the success of introduced species is related to the diversity of native species through trait-based processes.Abiotic site characteristics may also affect a site’s susceptibility to invasion.We quantified resident plant species richness,phylogenetic diversity and several abiotic site characteristics for 24 oak forests in Minnesota,USA,to assess their impact on the abundance of a widespread,introduced terrestrial plant species,common buckthorn(Rhamnus cathartica L.).Specifically,we asked(1)whether resident species richness and phylogenetic diversity affected the abundance of R.cathartica and(2)what site characteristics explained the overall abundance of R.cathartica.Methods Our survey included 24 oak-dominated stands in Minnesota’s deciduous forests.In each stand,we identified all species in 16 plots.We also measured a series of environmental site characteristics,including canopy openness(a proxy for light availability),percent bare soil,soil pH,percent sand,an index of propagule availability,duff layer thickness(a proxy for earthworm activity),an index of insolation and slope.For all species present in at least one site,we estimated a community phylogeny.We combined all sitelevel characteristics,including phylogenetic diversity of the resident plant species,in a multiple regression model to examine site-level drivers of community invasibility.Important Findings Results indicate that sites with higher overall plant phylogenetic diversity harbor less R.cathartica,even though native species richness was not significantly related to R.cathartica abundance.Regression analyses indicated that,in addition to resident species phylogenetic diversity,the most important predictors of R.cathartica abundance were canopy openness and the amount of bare soil,both positively related to the abundance of the invader.By combining the effects of abiotic site characteristics and resident species phylogenetic diversity in a model that predicted the abundance of R.cathartica,we were able to simultaneously account for a wide range of factors that might influence invasibility.Overall,our results suggest that management strategies aimed at reducing disturbances that lead to increased bare soil and light levels may be more successful if they also maximize phylogenetic diversity of the resident plant community. | Timothy J.S.Whitfeld Alexandra G.Lodge Alexander M.Roth Peter B.Reich | 2014 | Journal of Plant Ecology2014，7，2： | 2 |
| 4 | Modulation of leaf economic traits and trait relationships by climate显示文摘 | Ian J.Wright Peter B.Reich Johannes H. C.Cornelissen Daniel S.Falster Philip K.Groom KoukiHikosaka WilliamLee Christopher H.Lusk üloNiinemets JacekOleksyn NoriyukiOsada HendrikPoorter David I.Warton MarkWestoby | 2005 | Global Ecology and Biogeography2005，，5： | 1 |
| 5 | Convergence towards higher leaf mass per area in dry and nutrient‐poor habitats has different consequences for leaf life span显示文摘 | Ian J.Wright MarkWestoby Peter B.Reich | 2002 | Journal of Ecology2002，，3： | 1 |
| 6 | Strategy shifts in leaf physiology, structure and nutrient content between species of high‐ and low‐rainfall and high‐ and low‐nutrient habitats显示文摘 | I. J.Wright P. B.Reich M.Westoby | 2001 | Functional Ecology2001，，4： | 1 |
| 7 | 富与富的差距显示文摘大约15年前,在《国家的工作》一书中,我将大多数发达国家的劳动力分三层。最底层的是提供个人服务的,主要分布在零售店、餐馆、旅馆和医院;中间一层是工厂或办公室工人,主要从事一些简单重复的劳动。 | 罗伯特·里兹(Robert B.Reich) | 2006 | 竞争力2006，，5： | 0 |
| 8 | Effects of soil warming history on the performances of congeneric temperate and boreal herbaceous plant species and their associations with soil biota显示文摘Aims Climate warming raises the probability of range expansions of warm-adapted temperate species into areas currently dominated by cold-adapted boreal species.Warming-induced plant range expansions could partly depend on how warming modifies relationships with soil biota that promote plant growth,such as by mineralizing nutri-ents.Here,we grew two pairs of congeneric herbaceous plants spe-cies together in soil with a 5-year warming history(ambient,+1.7℃,+3.4℃)and related their performances to plant-beneficial soil biota.Methods Each plant pair belonged to either the mid-latitude temperate climate or the higher latitude southern boreal climate.Warmed soils were extracted from a chamberless heating experiment at two field sites in the temperate-boreal ecotone of North America.To isolate poten-tial effects of different soil warming histories,air temperature for the greenhouse experiment was identical across soils.We hypothesized that soil with a 5-year warming history in the field would enhance the performance of temperate plant species more than boreal plant species and expected improved plant performances to have positive associations with plant growth-promoting soil biota(microbial-feeding nematodes and arbuscular mycorrhizal fungi).Important Findings Our main hypothesis was partly confirmed as only one temperate spe-cies performed better in soil with warming history than in soil with his-tory of ambient temperature.Further,this effect was restricted to the site with higher soil water content in the growing season of the sampling year(prior to soil collection).One of the boreal species performed con-sistently worse in previously warmed soil,whereas the other species showed neutral responses to soil warming history.We found a positive correlation between the density of microbial-feeding nematodes and the performance of one of the temperate species in previously wetter soils,but this correlation was negative at the site with previously drier soil.We found no significant correlations between the performance of the other temperate species as well as the two boreal species and any of the studied soil biota.Our results indicate that soil warming can modify the relation between certain plant species and microbial-feeding nematodes in given soil edaphic conditions,which might be important for plant performance in the temperate-boreal ecotone. | Madhav P.Thakur Peter B.Reich Cameron Wagg Nicholas A.Fisichelli Marcel Ciobanu Sarah E.Hobbie Roy L.Rich Artur Stefanski Nico Eisenhauer | 2017 | Journal of Plant Ecology2017，10，4： | 0 |
| 9 | Promise and pitfalls of modeling grassland soil moisture in a free-air CO_(2) enrichment experiment(BioCON)using the SHAW model显示文摘Free-air carbon dioxide(CO_(2))enrichment(FACE)experiments provide an opportunity to test models of heat and water flow under novel,controlled situations and eventually allow use of these models for hypothesis evaluation.This study assesses whether the United States Department of Agriculture SHAW(Simultaneous Heat and Water)numerical model of vertical one-dimensional soil water flow across the soil-plant-atmosphere continuum is able to adequately represent and explain the effects of increasing atmospheric CO_(2) on soil moisture dynamics in temperate grasslands.Observations in a FACE experiment,the Bio CON(Biodiversity,CO_(2),and Nitrogen)experiment,in Minnesota,USA,were compared with results of vertical soil moisture distribution.Three scenarios represented by different plots were assessed:bare,vegetated with ambient CO_(2),and similarly vegetated with high CO_(2).From the simulations,the bare plot soil was generally the wettest,followed by a drier high-CO_(2) vegetated plot,and the ambient CO_(2) plot was the driest.The SHAW simulations adequately reproduced the expected behavior and showed that vegetation and atmospheric CO_(2) concentration significantly affected soil moisture dynamics.The differences in modeled soil moisture amongst the plots were largely due to transpiration,which was low with high CO_(2).However,the modeled soil moisture only modestly reproduced the observations.Thus,while SHAW is able to replicate and help broadly explain soil moisture dynamics in a FACE experiment,its application for point-and time-specific simulations of soil moisture needs further scrutiny.The typical design of a FACE experiment makes the experimental observations challenging to model with a one-dimensional distributed model.In addition,FACE instrumentation and monitoring will need improvement in order to be a useful platform for robust model testing.Only after this can we recommend that models such as SHAW are adequate for process interpretation of datasets from FACE experiments or for hypothesis testing. | Raquel H.FLINKER M.Bayani CARDENAS Todd G.CALDWELL Gerald N.FLERCHINGER Roy RICH Peter B.REICH | 2021 | Pedosphere2021，31，5： | 0 |
| 10 | 美国可能滑向双底衰退显示文摘美国最新公布的经济数据令投资者失望,股市应声下跌。美国加州大学伯克利分校公共政策教授、克林顿政府的劳工部长Robert B.Reich在为《金融时报》撰写的文章中表示,美国经济的症结出现在需求一方,消费者的忧虑情绪阻碍了消费,他建议政府采取措施提高民众收入。他认为华盛顿方面的麻痹降低了明智政策出台的可能性,美国经济落入双底衰退的可能性依旧存在。 | Robert B.Reich 多杰 | 2011 | 股市动态分析2011，，23： | 0 |
| 11 | 酸雨和臭氧对乔木幼苗菌根感染的影响显示文摘接近大气降雨速度与浓度的酸雨和臭氧,对北方红栎幼苗和东方白松幼苗的菌根感染引起了显著的变化。酸雨处理可造成菌根感染的减少,改变根际的营养关系,对栎树幼苗的光合作用生长情况没有影响,而对白松幼苗具有刺激作用;臭氧则是通过改变幼苗的代谢作用影响菌根。 | Peter B.Reich 陶秀成 苏智光 | 1987 | 环境科学研究1987，，6： | 0 |
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