title: Predicting stochastic community dynamics in grasslands under the assumption of competitive symmetry.
abstract: Community dynamics is influenced by multiple ecological processes such as environmental spatiotemporal variation, competition between individuals and demographic stochasticity. Quantifying the respective influence of these various processes and making predictions on community dynamics require the use of a dynamical framework encompassing these various components. We here demonstrate how to adapt the framework of stochastic community dynamics to the peculiarities of herbaceous communities, by using a short temporal resolution adapted to the time scale of competition between herbaceous plants, and by taking into account the seasonal drops in plant aerial biomass following winter, harvesting or consumption by herbivores. We develop a hybrid inference method for this novel modelling framework that both uses numerical simulations and likelihood computations. Applying this methodology to empirical data from the Jena biodiversity experiment, we find that environmental stochasticity has a larger effect on community dynamics than demographic stochasticity, and that both effects are generally smaller than observation errors at the plot scale. We further evidence that plant intrinsic growth rates and carrying capacities are moderately predictable from plant vegetative height, specific leaf area and leaf dry matter content. We do not find any trade-off between demographical components, since species with larger intrinsic growth rates tend to also have lower demographic and environmental variances. Finally, we find that our model is able to make relatively good predictions of multi-specific community dynamics based on the assumption of competitive symmetry.
authors.affiliation: LISC-Laboratoire d'Ingénierie pour les Systèmes complexes, IRSTEA, 9 Avenue Blaise Pascal, CS 20085, 63178 Aubière, France. Electronic address: theophile.lohier@gmail.com.
authors.forename: Théophile
authors.initials: T
authors.lastname: Lohier
authors.affiliation: LISC-Laboratoire d'Ingénierie pour les Systèmes complexes, IRSTEA, 9 Avenue Blaise Pascal, CS 20085, 63178 Aubière, France. Electronic address: franck.jabot@m4x.org.
authors.forename: Franck
authors.initials: F
authors.lastname: Jabot
authors.affiliation: Institute of Biology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany. Electronic address: alexandra.weigelt@uni-leipzig.de.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Weigelt
authors.affiliation: Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland. Electronic address: bernhard.schmid@ieu.uzh.ch.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmid
authors.affiliation: LISC-Laboratoire d'Ingénierie pour les Systèmes complexes, IRSTEA, 9 Avenue Blaise Pascal, CS 20085, 63178 Aubière, France. Electronic address: guillaume.deffuant@irstea.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Deffuant
mesh_terms: D018533:Biomass; D065948:Grassland; D008962:Models, Theoretical; D063245:Plant Development; D010944:Plants; D013045:Species Specificity; D013269:Stochastic Processes
keywords: Demographic stochasticity; Ecological modelling; Environmental stochasticity; Plant functional trait; Statistical inference