Document: MIC-3-92-11
The effects of environmental variation on ecological invasions.
NEUBERT, M.* 1, M.KOT 2 and M.LEWIS 3
Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA 1
University of Tennessee, Knoxville, TN 37996 USA 2
University of Utah, Salt Lake City, UT 84112 USA 3
Abstract:
Species invasions are increasingly frequent and have dramatic ecological and economic consequences. A key to coping with invasive species is the ability to predict their rates of spread. Traditional models of ecological invasions assume that the environment is temporally constant and spatially homogeneous. In fact, invading organisms regularly encounter fluctuations in environmental conditions and these translate into variation in the vital rates and/or dispersal rates. We have incorporated this variation into invasion models based on integrodifference equations by allowing the parameters to vary in either time or space. Using these models, we have derived formulae for the expected invasion speed. When environmental variation is temporal, the formula depends upon the geometric mean of the population growth rate at low densities. When the variation is spatial, the formula depends upon the scale of the variability relative to the scale of dispersal. In this poster we will present these formulae and show: 1) how to formulate integrodifference equation models; 2) how to include environmental variability; and 3) how to calculate the expected invasion speed.
Keywords: invasions, integrodifference equations
This abstract is being presented at: 10:30 AM in session:
RESTORATION ECOLOGY AND INVASIONS