Reproduktionsrate

Reproduktionsrate, or reproduction rate, is a concept used in demography and ecology to describe the average reproductive output of a population or individual over a defined period. It can refer to per-capita birth rates, or to generation-wide measures such as gross and net reproduction rates.

Gross reproduction rate (GRR) measures the number of daughters a female would have if current fertility remained constant and mortality were ignored. Net reproduction rate (NRR) adjusts for mortality and reflects the expected number of daughters that would survive to reproductive age per female. In practice, these measures are derived from age-specific fertility and survival data. In other contexts, the per-capita birth rate, often denoted b, represents the rate at which individuals produce offspring per unit time and, together with survival, helps determine the population growth rate.

In population ecology, the reproduction rate interacts with survival to yield metrics such as the finite growth factor lambda (λ) or the intrinsic rate of increase (r). In epidemiology, related concepts include the reproduction number (R or R0), which describes how many secondary cases one infectious individual generates in a wholly susceptible population; although not identical, it shares the idea of a reproduction potential.

Applications include forecasting population size, assessing conservation status, and planning resource management in wildlife, fisheries, and agriculture. Limitations include dependence on age structure, sex ratios, mortality, migration, and environmental variation, which can cause the reproduction rate to change over time.