Complex Adaptive System Theory Based Food Chain Modeling And Simulation

Food chains are the primary components and existing form of ecosystem. The researches of food chains are significant in the understanding of ecosystem and solving the ecological problems. Food chains are typical complex systems, so traditional methods are ineffective on them. The development of complex system theory, especially the introduction of complex adaptive system(CAS) theory, has provided a new way for the research of food chains.Based on the CAS theory, a fundamental food chain model is established. The modeling object is the food chain in grassland ecosystem which is a representative one. The model consists of environment, grass agents, herbivore agents, carnivore agents and interaction rules among agents or between agents and environment. The environment is grassland where grass and animal agents exist. Predation relations link these agents to form the food chain. By extracting and modeling the properties and behavior rules of grass and various animals, the model tries to reflect the common comprehensive properties of all kinds of food chains. The Java programming technology is used to implement the model on the Swarm simulation platform. The species, amounts and interaction rules of agents in food chain can be set conveniently to simulate food chains with different compositions and structures. In addition, there are graphic user interface to control and setup simulation, and graphs to show the status or statistic data generated in simulation. Then simulations are conducted on the model to simulate various food chains. The results of simulation show well some observations of real-life food chains. Some qualitative results can be drawn on the population dynamics, and relation between the composition and macro properties of food chain. For the purpose to understand the better evolution characteristics of food chains, some efforts are made to model individual evolution model and elementary swarm evolution model and the simulation results show that the model is feasible and effective.