Nature 334, 613 - 614 (18 August 1988); doi:10.1038/334613a0

The variability of population densities

Stuart L. Pimm^*† & Andrew Redfearn^†

^*Department of Zoology and ^†Graduate Program in Ecology, The University of Tennessee, Knoxville, Tennessee 37996, USA

The variability of population densities over time (henceforth called population variability) is one of several meanings of ecological stability¹. Here we show that estimates of the variability of population densities increase as we increase the number of years included in their calculation. This result appears for the majority of populations surveyed and over almost all the time intervals over which we calculate the variability. This result has implications for the debate over whether populations have an equilibrium.

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