Emergent properties in individual-based ecological models -: introducing case studies in an ecosystem research context

Individual-based models (IBM) extend the potential of ecological models to cope with spatial heterogeneity and complex ecological interaction networks with variable structures. This paper introduces a series of IBM-applications in the ecosystem research project 'Bornhoved Lakes District'. Here we outline the general theoretical implications of individual-based modelling related to self-organisation processes and emergent properties in different fields of ecological research and characterise the conceptual basis common to these applications. The case studies introduced are: spatial dispersal and colonisation processes of terrestrial arthropods community dynamics and trophic interaction in small mammals limnological application-spatially explicit fish energetic population model plant root system development and nutrient acquisition dynamics plant architecture and assimilation physiology We used the IBM-approach to analyse fundamental biocenotical interactions and investigate, how dispersal processes, behavioural characteristics and energetics at the level of individual organisms are linked with the population level and community processes as well as with ecosystem and landscape structures. The ecosystem based investigations are presented together with an overview of the employed modelling methodology. In addition, it is explained, how the conceptual background of emergent properties is involved in this approach. The individual-based modelling approach allows realistic descriptions and is highly adaptive to particular contexts and questions under investigation. Its main feature is that the characteristics of higher level ecological units like populations or communities can be determined as emergent properties from the lower ones. (c) 2004 Elsevier B.V All rights reserved.