Individual-based modelling as an integrative approach in theoretical and applied population dynamics and food web studies

Traditional modelling approaches in population dynamics and food web studie s do not incorporate the basic biological principles that each individual i s different and that interactions between individuals are inherently local. This notion has led to the development of so-called individual-based model s of populations and communities. A population or community is described as a database of individuals, whereby each individual is described in a numbe r of traits and a number of processes that change these traits over time. T his approach allows for incorporating significantly more detail compared wi th unstructured and physiologically structured models. Nowadays, the indivi dual-based approach is widely applied in both animal and plant ecology. The se applications, of which some representative examples are briefly describe d in this chapter, show that individual-based models can be used to bridge the gap between theoretical studies that focus on general features of ecosy stems and applied studies that are designed to predict the dynamics of ecos ystems under management scenarios. Individual-based models can contribute t o theoretical studies because they accommodate small but biologically relev ant detail, which cannot be included in analytical models. In applied studi es, they have proven to be quite flexible in using those data that are typi cally available from field studies. The advantages of individual-based mode lling come at the cost of technical and numerical complexity, necessary to cope with the numerous book-keeping operations that individual-based models essentially come down to. Various frameworks are now available to enhance the development of individual-based models. We expect individual-based mode ls to become established as a standard tool in ecological research within t he near future because the individual-based modelling paradigm provides a g eneral structure of the formalization and analysis of community and food we b dynamics.