intrinsic rate of natural increase

The intrinsic rate of natural increase (r) is a measure used in population ecology to quantify how quickly a population can grow. It represents the difference between the birth rate and the death rate per generation time.12

A positive value for r indicates that a population is increasing, with a higher value signifying a faster growth rate. Conversely, an r value of zero suggests a stable population with no growth or decline. This rate is particularly useful for comparing the growth potential of different species, especially when they have varying generation times. For instance, species with shorter generation times and earlier reproduction, like mice, tend to have higher intrinsic rates of natural increase than species with longer generation times, such as elephants.1