SOME NOTES ON COMPLEXITY IN VEGETATION

Vegetation is considered as a complex system with many subsystems. The system functions by using solar radiation as energy source and produc ing biomass and biodiversity. The different subsystems are connected b y feedback loops and interact in a process of self-organisation. It ap pears impossible to characterize this system with mathematical express ions, because most of the basic processes are non-linear. Instead, veg etation can be described with dynamical models. Selection, competition as well as positive interactions can occur. The model accounts for th e general dynamics, particularly fluctuations (when the system is in a steady state) and the climax situation. Many problems remain open: e. g. arbitrary limits of the system and its subsystems, macrostate/micro state relationships, thresholds and attractors. Single aspects of the subsystems can be linearized, but not the system as a whole and conseq uently its behaviour remains unpredictable.