Document: VOL-3-26-4

Individual-based modelling: The thing we need is a plan.

GRIMM, V.*

UFZ Centre for Environmental Research Leipzig-Halle, GERMANY ¹

Abstract:
Individual-based modelling, i.e. modelling based on individuals as discrete and unique entities, is established now in ecology. But despite the high potential of this modelling approach, it is still unclear if it will improve either ecological theory or ecological applications. A review of individual-based models of animal populations published in the last decade reveals two main reasons for this situation: most individual-based models (IBMs) are developed and analyzed without reference to ecological theory, and we lack explicit strategies for developing and, in particular, analyzing IBMs. Such strategies, however, are highly needed because otherwise IBMs easily become too complex and are only poorly analyzed. As a strategy for developing models, I propose "pattern-oriented modelling" which uses patterns observed in nature as the point of departure for modelling. As a strategy for analyzing IBMs, I propose simply to perform (computer) experiments with the models. A decisive element of this strategy is "graphical debugging", i.e. a graphical interface which displays model variables on different hierarchical levels. Graphical debugging is not only useful for developing and analyzing IBMs, but also for communicating them. I will demonstrate pattern-oriented modelling, computer experiments, and graphical debugging with a model of the spatio-temporal dynamics of Mid-European natural beech forests.

Keywords: Individual-based modeling, ecological theory, pattern-oriented modeling, graphical debugging

This abstract is being presented at: 8:10 AM in session:
Symposium # 27: Advancing the Individual-Based Modeling Approach: New Tools and Concepts.