LEVELS OF DENSITY VARIATION - THE ADEQUACY OF INDEXES AND CHAOS

Density variations of small rodents do not converge to two distinct levels; spatial and temporal variability and gradients occur and may be analysed by 'cyclicity indices' or other statistical methods. No single index is perfect and recent studies have made use of two or more indices. Present evidence does not give any definite support to the notion of chaotic dynamics in either rodent or other animal populations. Analyses of fluctuation patterns, e.g. by various indices, in relation to environmental factors seem more rewarding.