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Individuals do count! Individual variability and stochastic population dynamics
Applied Math| Speaker: | Bruce Kendall, Donald Bren School for the Environment, UC Santa Barbara |
| Location: | 693 Kerr |
| Start time: | Fri, Mar 15 2002, 4:10PM |
Population viability analysis (PVA) is a technique that employs stochastic demographic models to predict extinction risk. All else being equal, higher variance in a demographic rate leads to a greater extinction risk. "Demographic stochasticity" represents variance due to differences among individuals. Current implementations of PVAs, however, assume that the expected fates of all individuals are identical. For example, demographic stochasticity in survival is modeled as a random draw from a binomial distribution. Together with Gordon Fox (University of South Florida), I have found that variation among individuals results in a change in the population-level demographic variance. I will demonstrate these results both qualitatively and quantitatively, and show that individual variability may often act to reduce the population-level demographic variance (thus increasing the long-term population growth rate and reducing the risk of extinction).
The first paper on this stuff just came out in the Feb. Conservation Biology, if anyone wants a preview.
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