An evolutionary perspective on leaf economics: phylogenetics of leaf mass per area in vascular plants.

Olivier Flores,Guido Brusa,Sylvie Gourlet‐Fleury,Robin J Pakeman,Simon Pierce,Ove Eriksson,Bruno E L Cerabolini,Peter B Reich,Renée M Bekker,Natalia Pérez‐Harguindeguy,Baptiste Testi,Pablo Cruz,Graciela M Rusch,Guillaume Cornu,Matthieu Delcamp,Jan P Bakker,Carly Golodets,Adeline Fayolle,Ian J Wright,Helena Freitas,Evan Weiher,Fernanda Vendramini,Michael Kleyer,Sandra Lavorel,D Kunzmann ,J Hodgson ,Maud Bernard-­Verdier ,Jiří Doležal ,Roberta Ceriani ,Éric Garnier ,V P Papanastasis ,Sandra Dı́az

doi:10.1002/ece3.1087

Abstract

In plant leaves, resource use follows a trade-off between rapid resource capture and conservative storage. This “worldwide leaf economics spectrum” consists of a suite of intercorrelated leaf traits, among which leaf mass per area, LMA, is one of the most fundamental as it indicates the cost of leaf construction and light-interception borne by plants. We conducted a broad-scale analysis of the evolutionary history of LMA across a large dataset of 5401 vascular plant species. The phylogenetic signal in LMA displayed low but significant conservatism, that is, leaf economics tended to be more similar among close relatives than expected by chance alone. Models of trait evolution indicated that LMA evolved under weak stabilizing selection. Moreover, results suggest that different optimal phenotypes evolved among large clades within which extremes tended to be selected against. Conservatism in LMA was strongly related to growth form, as were selection intensity and phenotypic evolutionary rates: woody plants showed higher conservatism in relation to stronger stabilizing selection and lower evolutionary rates compared to herbaceous taxa. The evolutionary history of LMA thus paints different evolutionary trajectories of vascular plant species across clades, revealing the coordination of leaf trait evolution with growth forms in response to varying selection regimes.

Highlights

We found that patterns of leaf mass per area (LMA) evolution consistently differed across growth forms, revealing evidence for a higher conservatism and slower trait evolution in woody species than in herbaceous species
This is a first indication of the existence of phylogenetic conservatism in LMA values within families which seems to interact with the overall effect of growth forms on LMA
We highlight the strong interaction between the evolution of growth forms and of leaf strategies, with woody species displaying slower leaf diversification and higher conservatism in LMA than herbaceous plant species

Summary

Introduction

Leaf morphology has evolved manifold variations across vascular plant species, there is strong evidence of a universal spectrum constraining leaf functioning from rapid resource capture to efficient resource use (Grime et al 1997; Reich et al 1997; Dıaz et al 2004; Wright et al 2004) This worldwide leaf economics spectrum (Wright et al 2004) consists of the correlated variation among several key plant traits, including leaf mass per area (LMA, the ratio between leaf dry mass and leaf area) which describes the dry mass investment for light interception per unit leaf area (Lambers and Poorter, 1992). Following the second hypothesis, LMA would have evolved under strong selection and be conserved along plant lineages, which would generate a consistent and detectable phylogenetic signal

Methods

Results

Conclusion