title: Economic and hydraulic divergences underpin ecological differentiation in the Bromeliaceae.
abstract: Leaf economic and hydraulic theories have rarely been applied to the ecological differentiation of speciose herbaceous plant radiations. The role of character trait divergences and network reorganization in the differentiation of the functional types in the megadiverse Neotropical Bromeliaceae was explored by quantifying a range of leaf economic and hydraulic traits in 50 diverse species. Functional types, which are defined by combinations of C3or Crassulacean acid metabolism (CAM) photosynthesis, terrestrial or epiphytic habits, and non-specialized, tank-forming or atmospheric morphologies, segregated clearly in trait space. Most classical leaf economic relationships were supported, but they were weakened by the presence of succulence. Functional types differed in trait-network architecture, suggesting that rewiring of trait-networks caused by innovations in habit and photosynthetic pathway is an important aspect of ecological differentiation. The hydraulic data supported the coupling of leaf hydraulics and gas exchange, but not the hydraulic safety versus efficiency hypothesis, and hinted at an important role for the extra-xylary compartment in the control of bromeliad leaf hydraulics. Overall, our findings highlight the fundamental importance of structure-function relationships in the generation and maintenance of ecological diversity.
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Jamie
authors.identifier: http://orcid.org/0000-0001-9899-8101
authors.initials: J
authors.lastname: Males
authors.affiliation: Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
authors.forename: Howard
authors.initials: H
authors.lastname: Griffiths
mesh_terms: D031229:Bromeliaceae / Q000033:anatomy & histology / Q000502:physiology*; D002980:Climate; D055669:Ecological and Environmental Phenomena; D018515:Plant Leaves / Q000033:anatomy & histology / Q000502:physiology; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D013045:Species Specificity; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water
keywords: adaptive radiation; leaf anatomy; leaf economics; leaf hydraulics; water relations