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GSA Annual Meeting in Seattle, Washington, USA - 2017

Paper No. 40-8
Presentation Time: 3:25 PM

A MINIMUM POPULATION EXTINCTION TIME DRIVEN BY STOCHASTIC ENVIRONMENTAL FORCING


SPALDING, Christopher, Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, DOERING, Charles R., Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109-1107; Department of Mathematics, University of Michigan, Ann Arbor, MI 48109-1043; Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040 and FLIERL, Glenn R, Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, cspaldin@caltech.edu

The number of individuals within a population, or number of species within a lineage, changes with time in an inherently stochastic manner. Fluctuations within such a stochastic trajectory have long been recognized as a pathway by which extinction occurs, particularly within small populations. However, it is less well understood how external sources of stochastic forcing, such as environmental variability, interact with a population's intrinsic stochasticity. In this work, we develop a model from which the typical time to extinction of a population is computed, subject to forcing from an environment that switches randomly between two states with differing death rates. We find that there exists a frequency of environmental fluctuations that minimizes the mean time to extinction. This “worst” switching rate scales in proportion to the population’s generation turnover timescale, indicating that different species are more at risk than others from a given timescale of environmental variability. We discuss the implications of this timescale-sensitivity for extinction selectivity during past extinction events within the geological record.

Session No. 40

T51. Biodiversity Dynamics in the Face of Environmental Change: Integrating Paleontological and Neontological Approaches to Macroevolution II
Sunday, 22 October 2017: 1:30 PM-5:30 PM
Room 608 (Washington State Convention Center)
Geological Society of America Abstracts with Programs. Vol. 49, No. 6
doi: 10.1130/abs/2017AM-303172
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