PSU Mark
Eberly College of Science Mathematics Department

Meeting Details

For more information about this meeting, contact Tim Reluga, Carina Curto.

Title:Being discrete with ecological invasions
Seminar:Theoretical Biology Seminar
Speaker:Tim Reluga, Penn State Math and Biology
Invasions are one of the most easily identified spatial phenomena in ecology, and have inspired a rich variety of theories for naturalists' consideration. However, a number of arguments over the sensitivities of invasion rates to stochasticity, density-dependence, localization, and discreteness persist. Some authors argue that stochasticity slows invasions, while others argue that stochasticity quickens invasions. In this talk, I will present a specific family of invasion models with discrete individuals where reproduction and dispersal are independent, and we resolve the controversy by proving 3 key principles: (1) dispersal stochasticity quickens invasions; (2) density-dependence slows invasions; and (3) demographic stochasticity in the presence of density dependence slows invasions. These principles rely on the opinion that invasions are best interpreted not as waves as originally envisioned Fisher, but as random walks as envisioned by Ellner, and that the discreteness of living organisms is fundamentally important. We conclude with a classification of invasion dynamics based on dispersal kernel tails, and show that even for some pushed waves, asymptotic speeds depend on carrying capacity.

Room Reservation Information

Room Number:MB106
Date:09 / 16 / 2014
Time:01:00pm - 01:50pm