Chaos, cycles and spatiotemporal dynamics in plant ecology

1 We review the problems concerned with describing ecological variability and explain why nonlinear systems theory and chaos may be of relevance for understanding pattern and change in ecosystems. 2 The basic concepts of chaos are considered briefly, where possible in the context of plant ecology. We outline the period doubling route to chaos and associated concepts of bifurcation, universality, sensitivity to initial conditions, dimensionality, attractors and Lyapunov exponents. 3 Examples are selected from the literature to illustrate how nonlinear models and time series analysis have already contributed to research in plant ecology. 4 Key methods used to detect the presence of chaos in ecological time series, including determination of the 'return map,' the Lyapunov exponent, the technique of nonlinear prediction and the method of surrogate data, are surveyed. We discuss how small sample-size, as typically acquired in field-studies, can act as a formidable limitation in such approaches. 5 Models of plant communities, which emphasize the importance of spatiotemporal dynamics, are outlined. The concept of deterministic chaos is shown to be useful in this setting also.