FUNKTION OCH STABILITET I SÖTVATTENSMODELLEKOSYSTEM / Function and Stability of Freshwater Model Ecosystems
Function and stability of five freshwater model ecosystems were studied during three months in 1985. Two of the models had no fish and the other three had fishpopulations of different kinds. The ecosystems intended to be models of a Lobelia/Isoetes-community in the oligotrophic lake Nedre Fryken. Most of the material for the model ecosystems was collected from a reference area in the lake. The study comprehended how to quantify the trophic levels with simple methods, when scaling down the ecosystem. The differences between the models and the Nedre Fryken seem to depend on phenomena of enclosing and balancing the model ecosystem. The models with fish were more equal to each other than those without fish. If the above results are taken in consideration, freshwater model ecosystems of this kind could be used to show longterm effects of pollutants in oligotrophic freshwater ecosystems. “Complete abstract not presented.”