On net reproductive rate and the timing of reproductive output

  • Author(s) / Creator(s)
  • Understanding the relationship between life-history patterns and population growth is central to demographic studies. Here we derive a new method for calculating the timing of reproductive output, from which the generation time and its variance can also be calculated. The method is based on the explicit computation of the net reproductive rate (R ) using a new graphical approach. Using 0 nodding thistle, desert tortoise, creeping aven, and cat’s ear as examples, we show how R and the timing of reproduction is calculated 0 and interpreted, even in cases with complex life cycles. We show that the explicit R formula allows us to explore the effect of all repro- 0 ductive pathways in the life cycle, something that cannot be done with traditional analysis of the population growth rate (l). Additionally, we compare a recently published method for determining population persistence conditions with the condition R 1 1 and 0 show how the latter is simpler and more easily interpreted biologically. Using our calculation of the timing of reproductive output, we illustrate how this demographic measure can be used to understand the effects of life-history traits on population growth and control.

  • Date created
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  • Type of Item
    Article (Published)
  • DOI
  • License
    Copyright 2008 by The University of Chicago
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  • Citation for previous publication
    • De-Camino-Beck, T., & Lewis, M. A. (2008). On net reproductive rate and the timing of reproductive output. The American naturalist, 172(1), 128-139.