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
Room Reservation Information
|Date:||09 / 16 / 2014|
|Time:||01:00pm - 01:50pm|