Different types of models are used to approach the different research questions that arise from the CASCADE project.
Basically two different types can be distinguished:
Cellular automata models are used to simulate the emergence of spatio-temporal dynamics of the vegetation. By applying very basic assumptions on the local properties of single plants they can generate characteristic patterns of vegetation cover that can be compared with aerial images from the sites. Cellular automata models are suited to investigate the change of patterns in response to pressures like drought or grazing. These patterns are a candidate for early warning signs for land degradation.
Ordinary differential equations are used to describe non-spatial dynamics of populations over time. Particularly the succession of plant species after recurring fire events can be investigated with this kind of models. They can, however, easily be extended by a spatial component.
Both models will be described in detail in the following sections.