title: Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model.
abstract: Functional diversity is critical for ecosystem dynamics, stability and productivity. However, dynamic global vegetation models (DGVMs) which are increasingly used to simulate ecosystem functions under global change, condense functional diversity to plant functional types (PFTs) with constant parameters. Here, we develop an individual- and trait-based version of the DGVM LPJmL (Lund-Potsdam-Jena managed Land) called LPJmL- flexible individual traits (LPJmL-FIT) with flexible individual traits) which we apply to generate plant trait maps for the Amazon basin. LPJmL-FIT incorporates empirical ranges of five traits of tropical trees extracted from the TRY global plant trait database, namely specific leaf area (SLA), leaf longevity (LL), leaf nitrogen content (Narea), the maximum carboxylation rate of Rubisco per leaf area (vcmaxarea), and wood density (WD). To scale the individual growth performance of trees, the leaf traits are linked by trade-offs based on the leaf economics spectrum, whereas wood density is linked to tree mortality. No preselection of growth strategies is taking place, because individuals with unique trait combinations are uniformly distributed at tree establishment. We validate the modeled trait distributions by empirical trait data and the modeled biomass by a remote sensing product along a climatic gradient. Including trait variability and trade-offs successfully predicts natural trait distributions and achieves a more realistic representation of functional diversity at the local to regional scale. As sites of high climatic variability, the fringes of the Amazon promote trait divergence and the coexistence of multiple tree growth strategies, while lower plant trait diversity is found in the species-rich center of the region with relatively low climatic variability. LPJmL-FIT enables to test hypotheses on the effects of functional biodiversity on ecosystem functioning and to apply the DGVM to current challenges in ecosystem management from local to global scales, that is, deforestation and climate change effects.
authors.affiliation: Potsdam Institute for Climate Impact Research (PIK), Telegraphenberg A31, Potsdam, 14473, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, 14195, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Sakschewski
authors.affiliation: Potsdam Institute for Climate Impact Research (PIK), Telegraphenberg A31, Potsdam, 14473, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, 14195, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: von Bloh
authors.affiliation: Potsdam Institute for Climate Impact Research (PIK), Telegraphenberg A31, Potsdam, 14473, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, 14195, Germany.
authors.forename: Alice
authors.initials: A
authors.lastname: Boit
authors.affiliation: Potsdam Institute for Climate Impact Research (PIK), Telegraphenberg A31, Potsdam, 14473, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, 14195, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Rammig
authors.affiliation: Max-Planck-Institute for Biogeochemistry, Jena, 07745, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Kattge
authors.affiliation: Forest Ecology and Forest Management Group, Wageningen University, PO Box 47, Wageningen, 6700AA, The Netherlands.
authors.forename: Lourens
authors.initials: L
authors.lastname: Poorter
authors.affiliation: Global Ecology Unit CREAF-CSIC-UAB, CSIC, Cerdanyola del Vallés, 08193, Catalonia, Spain.|CREAF, Cerdanyola del Vallès, 08193, Catalonia, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Peñuelas
authors.affiliation: Potsdam Institute for Climate Impact Research (PIK), Telegraphenberg A31, Potsdam, 14473, Germany.|Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, 14195, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Thonicke
keywords: Amazon rainforest; dynamic global vegetation model; functional diversity; gap model; individual-based model; leaf economics spectrum; trade-off; trait variability