Table 1.

Variability of prey population sizes, prey resource use ability (maximum population size) and prey diversity. (Values are mean coefficient of variation (CV) of six replicate microcosms ±1 s.e.m. CV is calculated from 14 consecutive data points for the prey population sizes, from nine data points for prey resource use ability (maximum population size in the absence of predation) and from five data points for prey diversity (Shannon diversity index).)

treatment	prey population size	prey resource use ability	prey diversity
predators absent, low	0.224±0.003	0.546±0.058	0.360±0.034
predators absent, high	0.246±0.009	0.249±0.020	0.405±0.047
predators present, low	0.970±0.056	0.756±0.105	0.457±0.088
predators present, high	0.618±0.073	0.262±0.011	0.196±0.071