@article{BergerPiouSchiffersetal.2008, author = {Berger, Uta and Piou, Cyril and Schiffers, Katja and Grimm, Volker}, title = {Competition among plants : concepts, individual-based modelling approaches, and a proposal for a future research strategy}, issn = {1433-8319}, year = {2008}, abstract = {Competition is a key process in plant populations and communities. We thus need, if we are to predict the responses of ecological systems to environmental change, a comprehensive and mechanistic understanding of plant competition. Considering competition, however, only at the population level is not sufficient because plant individuals usually are different, interact locally, and can adapt their behaviour to the current state of themselves and of their biotic and abiotic environment. Therefore, simulation models that are individual-based and spatially explicit are increasingly used for studying competition in plant systems. Many different individual-based modelling approaches exist to represent competition, but it is not clear how good they are in reflecting essential aspects of plant competition. We therefore first summarize current concepts and theories addressing plant competition. Then, we review individual-based approaches for modelling competition among plants. We distinguish between approaches that are used for more than 10 years and more recent ones. We identify three major gaps that need to be addressed more in the future: the effects of plants on their local environment, adaptive behaviour, and below-ground competition. To fill these gaps, the representation of plants and their interactions have to be more mechanistic than most existing approaches. Developing such new approaches is a challenge because they are likely to be more complex and to require more detailed knowledge and data on individual-level processes underlying competition. We thus need a more integrated research strategy for the future, where empirical and theoretical ecologists as well as computer scientists work together on formulating, implementing, parameterization, testing, comparing, and selecting the new approaches. (c) 2008 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.}, language = {en} } @article{GrimmBergerBastiansenetal.2006, author = {Grimm, Volker and Berger, Uta and Bastiansen, Finn and Eliassen, Sigrunn and Ginot, Vincent and Giske, Jarl and Goss-Custard, John and Grand, Tamara and Heinz, Simone K. and Huse, Geir and Huth, Andreas and Jepsen, Jane U. and Jorgensen, Christian and Mooij, Wolf M. and Mueller, Birgit and Piou, Cyril and Railsback, Steven Floyd and Robbins, Andrew M. and Robbins, Martha M. and Rossmanith, Eva and Rueger, Nadja and Strand, Espen and Souissi, Sami and Stillman, Richard A. and Vabo, Rune and Visser, Ute and DeAngelis, Donald L.}, title = {A standard protocol for describing individual-based and agent-based models}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {198}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2006.04.023}, pages = {115 -- 126}, year = {2006}, abstract = {Simulation models that describe autonomous individual organisms (individual based models, IBM) or agents (agent-based models, ABM) have become a widely used tool, not only in ecology, but also in many other disciplines dealing with complex systems made up of autonomous entities. However, there is no standard protocol for describing such simulation models, which can make them difficult to understand and to duplicate. This paper presents a proposed standard protocol, ODD, for describing IBMs and ABMs, developed and tested by 28 modellers who cover a wide range of fields within ecology. This protocol consists of three blocks (Overview, Design concepts, and Details), which are subdivided into seven elements: Purpose, State variables and scales, Process overview and scheduling, Design concepts, Initialization, Input, and Submodels. We explain which aspects of a model should be described in each element, and we present an example to illustrate the protocol in use. In addition, 19 examples are available in an Online Appendix. We consider ODD as a first step for establishing a more detailed common format of the description of IBMs and ABMs. Once initiated, the protocol will hopefully evolve as it becomes used by a sufficiently large proportion of modellers. (c) 2006 Elsevier B.V. All rights reserved.}, language = {en} }