Catastrophes and the increased risk of population extinction
- Event time: 11:30am
- Event date: 30th June 2010
- Speaker: Neelofer Banglawala (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
Natural populations are vulnerable to extinction, and determining the probability of extinction for a wide range of scenarios is a key theme in population biology. One such scenario is a catastrophic event, i.e. a temporary but marked decrease in the population's time-dependent reproduction rate. Using the (Verhulst) logistic model, Assaf et al. (2009) have recently determined the increase in population extinction risk resulting from such an event.
I will present their results as a pedagogical example of how to calculate first-passage properties from an exact Master equation, using a time-dependent eikonal approximation and carrying out an optimal path (instanton) calculation. This formalism produces asymptotically correct results where van Kampen's system size expansion fails.
This is a roughly weekly series of didactical blackboard talks focussing on some theoretical aspect of Condensed Matter, Biological, and Statistical Physics..