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

ABSTRACT 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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Available from: Bill Shipley, Sep 26, 2015
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    • "For example, changes in the functional diversity of easily measured traits such as SLA and LDMC are often used to distinguish biotic and abiotic processes in trait-based community assembly. This makes some sense in that variation in SLA and LDMC within and among species reflects difference in capture of light, soil nutrient, and water resources (Reich 2014), but SLA and LDMC are only part of a functionally linked suite of foliar traits that includes LP, LN, A max , and R dark (Shipley et al. 2006, Reich 2014). Any single trait in this leaf economic spectrum responds to multiple environmental factors in ways constrained by functional linkages to other foliar and non-foliar traits reflecting a variety of plant functions at the whole plant level (Marks and Lechowicz 2006b, Reich 2014). "
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    ABSTRACT: Niche differentiation arising in functional trait diversity is expected to increase the potential for species coexistence, but empirical evidence for these relationships is sparse. We test whether grazing increases the functional diversity of leaf traits and niche differentiation in phosphorus limited Tibetan alpine meadows. We measured five traits in the leaf economic spectrum (LES; LC, leaf carbon concentration; LN, leaf nitrogen concentration; LP, leaf phosphorus concentration; SLA, specific leaf area; and LDMC, leaf dry matter content) for all species occurring in grazed and ungrazed plots at each of five sites. By comparing indicators of the fundamental and realized niches of co-occurring plants in both grazed and ungrazed plots, we quantified a grazing-mediated competitive effect on trait divergence and convergence. This trait response reflects the relative importance of niche differentiation and competitive exclusion in response to grazing. We found that while grazing induced LP divergence, both LC and LN tended to converge under grazing. Grazing had no effect on either SLA or LDMC diversity. When all five traits are considered together as a functionally integrated suite (LES hypervolume), there is no evidence for either divergence or convergence in response to grazing. Although grazing promotes functionally relevant diversity in LP that enables niche differentiation in competition for scarce soil available P, these results suggest that coordinated shifts in other LES traits sustain effective overall foliar function despite shifts in LP.
    Ecosphere 09/2015; 6(9):Artical 150. DOI:10.1890/ES14-00547.1 · 2.26 Impact Factor
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    • "To estimate the balance among multiple factors affecting community assembly following grazing, one therefore should consider the FD of traits both singly and in aggregate (Flynn et al. 2009; Pakeman 2011; Mason et al. 2013; Karadimou et al. 2014). In this paper we assess the functional basis for changes in the diversity of Tibetan alpine meadow communities under grazing by analyzing changes in five traits in the leaf economics spectrum (LES) that interact to determine foliar function (Wright et al. 2004; Shipley et al. 2006). Based on previous work and with regard to the responses of single traits, we expected that: (i) removal of biomass would reduce competition for light in grazed communities, leading to a decrease in the FD of foliar carbon content (Niu et al. 2009, 2010; Borer et al. 2014); (ii) grazing would decrease competitive exclusion attributable to acquisition of scarce soil nutrients, hence increasing FD in foliar nutrient concentration leaf nitrogen concentration (LNC), and leaf phosphorus concentration (LPC) in these nutrient limited alpine meadows (Yang et al. 2014; Niu et al. 2015); (iii) the effect of grazing on the FD of SLA and LDMC will depend on the balance between decreasing light competition and increasing competition for soil nutrients and water (Bagchi and Ritchie 2010). "
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    • "Plant invasion is often accompanied by an increase in stand biomass (Ehrenfeld 2010; Vila and others 2011; Castro-Diez and others 2014; Maron and others 2014), which may result in increased soil carbon (C) sequestration (Luyssaert and others 2008; Nave and others 2013; Ziter and MacDougall 2013). On the other hand, relative to native vegetation , invader biomass often has higher tissue quality (less lignin and more nutrients) typical of species with high growth rates (Castro-Diez and others 2014; Meisner and others 2014) and associated with faster tissue turnover and decomposition (Dıàz and others 2004; Dijkstra and others 2006; Shipley and others 2006). The faster decomposition rates of invaders potentially result in more rapid loss of organic matter from the ecosystem compared with native systems, which can decrease soil C sequestration (Peltzer and others 2009). "
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    ABSTRACT: Plant invasion often increases stand biomass, but higher tissue quality (for example, less lignin and more nutrients) in invasive species might accelerate litter decomposition. This mechanism may minimize increases in soil carbon (C) sequestration despite higher production. Our knowledge about invasion and tissue quality is based on shoots, but roots contribute 50–90% of biomass in vegetation types such as semiarid grasslands. Here we investigate root decomposition rates and tissue quality in the widespread invasive grass Agropyron cristatum, which doubles root mass but not soil C in the Great Plains of North America. Root length was significantly greater beneath Agropyron than native grassland 7 years after minirhizotron installation. However, CO2 evolution from decomposing roots was twice as much for Agropyron roots as for native grass roots (P < 0.05). CO2 evolution from decomposing native grass roots was not significantly different from controls with no root tissue added, suggesting that Agropyron invasion can convert grassland soil to a source of CO2 to the atmosphere. Rapid root decomposition was associated with significantly lower lignin content in Agropyron roots than native grass roots, although root N and lignin:N ratios did not differ. We present the first report of root decomposition rates associated with plant invasion. Increases in root length were accompanied by increased root decomposition rates of low-lignin tissue, such that invasion-driven enhanced productivity did not enhance soil C sequestration. Among-species differences in root tissue quality and decomposition rates could influence soil C dynamics during invasions of systems dominated by belowground production, such as tundra, boreal forests, and semiarid grassland.
    Ecosystems 07/2015; DOI:10.1007/s10021-015-9900-y · 3.94 Impact Factor
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