Network for Biological Invasions and Dispersal Research

MITACS Seminar at the University of Ottawa, Ottawa

Wednesday, 4 November, 2009,

Allison Kolpas

of the University of Delaware

will speak on

Effects of Demographic Stochasticity on Population Persistence in Advective Media

2:45 PM, KED B015, University of Ottawa, Ottawa

Abstract: Many populations live and disperse in advective media. A fundamental question, known as the ``drift paradox" in stream ecology, is how a closed population can survive when it is constantly being transported downstream by the flow. Recent population-level models have focused on the role of diffusive movement in balancing the effects of advection, predicting critical conditions for persistence. Here, we formulate an individual-based stochastic model to quantify the effects of demographic stochasticity on persistence. When there is no correlation in the movement of inter-patch residents, stochasticity smooths the persistence-extinction boundary, while when individuals disperse in ``packets" from one patch to another and the flow field is memoryless on the timescale of packet transport, the probability of persistence is greatly enhanced.