Fundamental trade-offs generating the worldwide leaf economics spectrum

Département de biologie, Université de Sherbrooke, Sherbrooke, Quebec, Canada.
Ecology (Impact Factor: 4.66). 04/2006; 87(3):535-41. DOI: 10.1890/05-1051
Source: PubMed


Recent work has identified a worldwide "economic" spectrum of correlated leaf traits that affects global patterns of nutrient cycling and primary productivity and that is used to calibrate vegetation-climate models. The correlation patterns are displayed by species from the arctic to the tropics and are largely independent of growth form or phylogeny. This generality suggests that unidentified fundamental constraints control the return of photosynthates on investments of nutrients and dry mass in leaves. Using novel graph theoretic methods and structural equation modeling, we show that the relationships among these variables can best be explained by assuming (1) a necessary trade-off between allocation to structural tissues versus liquid phase processes and (2) an evolutionary tradeoff between leaf photosynthetic rates, construction costs, and leaf longevity.

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    • "Four taxa could not be placed: Bactris trichophylla, Hedyosmum maxicanum , and two unknown species of the genus Nephrolepsis, and these were pruned from the GLOPNET dataset for our analyses. In order to determine whether phylogeny is, in fact, a problem for the Shipley et al. (2006) analysis, we assessed the extent of phylogenetic non-independence on trait distributions . Phylogenetic signal was estimated as Pagel's k for the phylogenetic residuals of each trait using the fitContinuous function in the R package geiger (Pagel 1999; Harmon et al. 2008; Revell 2010). "
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    ABSTRACT: The leaf economics spectrum (LES) is a prominent ecophysiological paradigm that describes global variation in leaf physiology across plant ecological strategies using a handful of key traits. Nearly a decade ago, Shipley et al. (2006) used structural equation modelling to explore the causal functional relationships among LES traits that give rise to their strong global covariation. They concluded that an unmeasured trait drives LES covariation, sparking efforts to identify the latent physiological trait underlying the 'origin' of the LES. Here, we use newly developed phylogenetic structural equation modelling approaches to reassess these conclusions using both global LES data as well as data collected across scales in the genus Helianthus. For global LES data, accounting for phylogenetic non-independence indicates that no additional unmeasured traits are required to explain LES covariation. Across datasets in Helianthus, trait relationships are highly variable, indicating that global-scale models may poorly describe LES covariation at non-global scales.
    Ecology Letters 11/2015; DOI:10.1111/ele.12542 · 10.69 Impact Factor
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    • "Exploring the functional trait scaling relationships among the metabolic rates, nutrient concentrations and morphological features of plants has been a hot topic in ecology in recent years (Osnas et al. 2013). Related investigations have greatly advanced our understanding of the growth strategies and resource-use patterns of plants, and provided a practical way to parameterise vegetation–climate models to predict the effects of climate change on terrestrial ecosystems and their responses (Cornelissen et al. 2007; Shipley et al. 2006; Wright et al. 2004). Previous studies revealed that the concentrations of nitrogen and phosphorus are closely associated with the light-saturated assimilation and dark respiratory rates of vascular plant leaves, and these traits have significant negative correlations with leaf mass per area (Karst and Lechowicz 2007; Wright et al. 2004). "
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    ABSTRACT: Ecophysiological studies of bryophytes have generally been conducted at the shoot or canopy scale. However, their growth forms are diverse, and knowledge of whether bryophytes with different shoot structures have different functional trait levels and scaling relationships is limited. We collected 27 bryophyte species and categorised them into two groups based on their growth forms: erect and prostrate species. Twenty-one morphological, nutrient and photosynthetic traits were quantified. Trait levels and bivariate trait scaling relationships across species were compared between the two groups. The two groups had similar mean values for shoot mass per area (SMA), light saturation point and mass-based nitrogen (Nmass) and phosphorus concentrations. Erect bryophytes possessed higher values for mass-based chlorophyll concentration (Chlmass), light-saturated assimilation rate (A mass) and photosynthetic nitrogen/phosphorus use efficiency. Nmass, Chlmass and A mass were positively related, and these traits were negatively associated with SMA. Furthermore, the slope of the regression of Nmass versus Chlmass was steeper for erect bryophytes than that for prostrate bryophytes, whereas this pattern was reversed for the relationship between Chlmass and A mass. In conclusion, erect bryophytes possess higher photosynthetic capacities than prostrate species. Furthermore, erect bryophytes invest more nitrogen in chloroplast pigments to improve their light-harvesting ability, while the structure of prostrate species permits more efficient light capture. This study confirms the effect of growth form on the functional trait levels and scaling relationships of bryophytes. It also suggests that bryophytes could be good models for investigating the carbon economy and nutrient allocation of plants at the shoot rather than the leaf scale.
    Oecologia 11/2015; DOI:10.1007/s00442-015-3484-2 · 3.09 Impact Factor
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    • "In addition , researchers have done much work on the origin of LES ( Shipley et al . , 2006 ; Blonder et al . , 2011 ; Vasseur et al . , 2012 ) . Although much progress has been made in LES among species , few studies investigated the application of LES within species ( but see Blonder et al . , 2013 ; Niinemets , 2015 ) . The main reasons may be related to the expected lower variation and much less concern about variation wit"
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    ABSTRACT: Leaf economics spectrum (LES), characterizing covariation among a suite of leaf traits relevant to carbon and nutrient economics, has been examined largely among species but hardly within species. In addition, very little attempt has been made to examine whether the existence of LES depends on spatial scales. To address these questions, we quantified the variation and covariation of four leaf economic traits (specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus contents) in a cosmopolitan wetland species (Phragmites australis) at three spatial (interregional , regional, and site) scales across most of the species range in China. The species expressed large intraspecific variation in the leaf economic traits at all of the three spatial scales. It also showed strong covariation among the four leaf economic traits across the species range. The coordination among leaf economic traits resulted in LES at all three scales and the environmental variables determining variation in leaf economic traits were different among the spatial scales. Our results provide novel evidence for within-species LES at multiple spatial scales, indicating that resource trade-off could also constrain intraspecific trait variation mainly driven by climatic and/or edaphic differences.
    Frontiers in Plant Science 10/2015; 6(901). DOI:10.3389/fpls.2015.00901 · 3.95 Impact Factor
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