Ecology, evolution and 1 f -noise.

Among ecologists, there has been a growing recognition of the importance of long-term correlations In environmental time series. The family of 1 f -noises - fluctuations defined in terms of the different timescales present - is a useful approach to this problem. White noise and the random walk, the two currently favoured descriptions of environmental fluctuations, lie at extreme ends of this family of processes. Recent analyses of data, results of models, and examination of basic 1 f -noise properties, suggest that pink 1 < f noise, which lies midway between white noise and the random walk, might be the best null model of environment variation. If true, this would have important consequences for the interpretation of ecological time series and for ecological and evolutionary modelling.