Quadling, Mark Sherwood2019-07-302019-07-301992https://hdl.handle.net/10539/27808A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg. in fulfilment of the requirements tor the degree of Master of ScienceThis thesis develops the theoretical basis of the qualitative frame based modelling technique, a paradigm recently proposed by Starfield for the modelling of ecosystems with a multiplicity of stable states. This technique is a refinement of the State-and- Transition conceptual model of Westoby et al which involves the division of the ecosystem dynamics into a catelog of stable 'states' and a suite of transitions between these states. The frame models of Starfield associate with each stable configuration of the ecosystem a qualitative rule based model for the key processes in that stable configuration. The aims of this thesis are the following, 1. A rigorous definition of frame modelling of dynamic ecosystems is proposed, and this theoretical foundation is used to demonstrate that qualitative frame models may be used to mode! dynamic ecosystems to an arbitrary accuracy. 2. The development of implementation software. A qualitative rule based frame modelling environment is presented. and a specification for an improved environment is proposed based on the theoretical work.enBiotic communities -- Computer simulationPopulation biology -- Computer simulationEcology -- Computer simulationFrames (Information theory)DynamicsThesis