Voinov, A.A. and Tonkikh, A.P., 1987. Qualitative model of eutrophication in macrophyte lakes. Ecol. Modelling, 35: 211-226. A model is proposed for a qualitative representation of ecosystem dynamics in a macrophyte water body. The model variables are the concentrations of phytoplankton, macrophytes, nutrients, detritus and dissolved oxygen. By methods of qualitative theory of differential equations the model steady-state dynamics are studied (the 'quasi-stationary' process). The resulting evolution of the water body is in good agreement with the existing ideas about the succession of vegetation types under increasing nutrient load.