Introduction

Chaos theory, which strictly is only a subset of non-linear systems theory, deals with systems whose long-term behaviour or output is prone to be complex, irregular, sensitive to small changes in initial conditions and unpredictable at specific localities. Amongst several recent texts that have aimed to popularize the theory and describe its remarkable history, those by Gleick (1988) and Coveney & Highfield (1991) are perhaps the most accessible. More detailed sources of information concerning specifically biological applications of nonlinear theory are provided by Degn, Holden & Olsen (1987) and by Sleeman (1989).

The aim of this chapter is to promote appreciation of the ways in which non-linear dynamics can be expected to apply to fungal individuals, populations and communities. It will be argued that non-linear theory has more than just a place in environmental mycology; it provides a basis for understanding the complexity, interconnectedness and limits to the predictability of natural patterns of distribution and activity of fungi.

Throughout the discussion, the focus will be on understanding of the sources and ecological importance of non-linearity, rather than on rigorous mathematical treatment. At the outset, an attempt will be made to generalize about the kinds of process which underlie non-linear dynamics and the organizational properties that these processes give rise to. The mechanisms by which these processes operate at individual, population, community and sub-cellular levels of organization will then be considered and related to the ways that fungal systems respond to sources of environmental heterogeneity.