THE GROWTH-RATE OF ZOOPLANKTON AT THE EDGE OF CHAOS - ECOLOGICAL MODELS

This paper tests the hypothesis that systems at the edge of chaos have the highest level of(thermodynamic) information, which supports the hypothesis that systems at the edge of the chaos can coordinate the most complex behavior. This is examined by the use of a realistic ecological lake model describing how an ecological system behaves (i.e. chaotic or ordered), and how the level of information in the system changes when some of the key properties of the focal classes of species are changed. The highest level of information (which is also Furthest from thermodynamic equilibrium, as information processes free energy) coincides with realistic properties (parameters) and with a system at the edge of the chaos. The model's key parameter was chosen as the maximum growth rate of zooplankton, as from lake studies, zooplankton growth rate reflects the conditions in the ecosystem and that different zooplankton species have different growth rates. If the key parameter is given a slightly higher value, chaotic behavior emerges. If fish is introduced to the system, the maximum information of the system increases. The maximum zooplankton growth rate giving the highest level of information is reduced if fish are present. This is in accordance with general observations-thus supporting the results. (C) 1995 Academic Press Limited