Detecting density dependence.

Populations that persist do so, not by a juggling act balancing their rate of increase against a pot-pourri of unpredictable environmental factors, but rather by one or more processes that are broadly density-dependent, at least at some time or in some place. Detecting such density dependence is clearly of major importance in ecology. Unfortunately, many existing life table studies which set out with the aim of quantifying such processes are flawed by their lack of attention to within-generation factors causing differential birth and/or death rates between individuals. These factors can be very important to population regulation and are easily overlooked in analyses using only average population estimates.