Complex Ecosystem Model Research Articles

Sector stability of a complex ecosystem model

By definition a partially feasible equilibrium is sector-stable if every solution of the system which begins in a nonnegative neighborhood remains in the same or a larger nonnegative neighborhood for all finite values of t and converges to the steady state as t→∞. It is argued that the concept of sector stability is important in the analysis of a complex ecosystem model. A nontrivial mathematical criterion is given for the total system property which states that the self-regulating intraspecific interactions are stronger than the interspecific interactions. This total system property ensures global stability or global sector stability in a model. It follows that such a model can withstand a wide range of realistic perturbations of its initial state.

The methods of modelling for pelagic and circumlittoral marins ecosystems

The described method of modelling of marine ecosystems is based on their decomposition into hierarchial structure of subsystems each of them may be considered separately. As a result of this the simplified qualitative correlations are established between the values of their input and output variables. The inputs and outputs of subsystems models are connected through the randomizing modules taking into account the description accuracy of real object by the corresponding model. In the complete form the mathematical model of complex ecosystem is a stochastic graph, which is investigated by the method of random trajectories. On the base of analysis of complex ecosystem models the limiting and loading variables are revealed, for which it is possible then to compose the simple models, describing the characteristic peculiarity of their behaviour. This principle is used for creation of the scheme of pollution action on marine ecosystems.