LACK OF PREDICTABILITY IN MODEL-ECOSYSTEMS BASED ON COUPLED LOGISTIC EQUATIONS

One of the major tasks for conservation and fishery biologists is the prediction of future population dynamics from relatively short time se ries of past data. Inspired by a recent paper of Alan Hastings and Kev in Higgins (Science, 263 (1994) 1133-1136) on long-term transients in realistic model ecosystems for spatially distributed populations, we e xplored the problem of predictability in analogous systems of coupled logistic equations. For such systems, with parameters in the 'chaotic range' as studied by A. Hastings and K. Higgins, we show that such pre dictions are at best extremely difficult. Consequences for conservatio n and fishery are explored.