HOST-PATHOGEN SYSTEMS IN A SPATIALLY PATCHY ENVIRONMENT

A discrete model for a host-pathogen system is developed and is used t o represent the dynamics in each patch within a landscape of n x n pat ches. These patches are linked by between-generation dispersal to neig hbouring patches. Important results (compared to similar 'coupled map lattice' studies) include an increase in the likelihood of metapopulat ion extinction if the natural loss of pathogen particles is low, and t he observation of a radial wave pattern (not previously reported) wher e the wavefront propagates uniformly from a central focus. This result has additional significance in that it permits the system to exhibit 'intermittency' between two quasi-stable spatial patterns: spirals and radial waves. With intermittent behaviour, the dynamics may look cons istent when viewed at one time scale, but over a longer time scale the y can alter dramatically and repeatedly between the two patterns. Ther e is also evidence of clear links between spatial structure and tempor al metapopulation behaviour in both the intermittent and 'pure' region s, verified by results from an algorithmic complexity measure and a sp ectral analysis of the temporal dynamics.