Modeling ecology and evolution in invasions: Spring 2009

Group exchange to understand how movement and local search neighborhood rules impact individual behavior

Global Invasion Network RCN Research Exchange Summary: April 14-16
Principal Participants: Andrew Kanarek, Colleen Webb, and Robert Holt

We had a productive 2.5 day research exchange at the University of Florida to discuss ecological and evolutionary processes and implications for establishment success of invasive species. Focusing primarily on how Allee effects influence population dynamics, we discussed two main aspects: 1) the ecological consequences and 2) specific modeling strategies for incorporating evolution.

Ecological consequences of Allee effects in introduced populations
Main Goal: To understand how movement and local search neighborhood rules impact individual behavior

Andrew Kanarek presented the model and his simulation results to Bob Holt, Mike Barfield, and Sam Scheiner. The primary point of discussion centered around the emergent clustering of individuals due to the rate of dispersal and neighborhood-of-influence kernel. We recognized that Allee effects and density dependence in general give rise to heterogeneous distributions of individuals across space, and population structuring, without differences in the physical habitat. Bob Holt suggested that these results parallel Keitt et al. (2001) in terms of invasion/range pinning, and proposed that this would be an interesting direction to take. Sam Scheiner proposed that density dependent dispersal may influence these dynamics, and Mike Barfield thought a Gaussian search kernel versus a top hat kernel may also make a difference.

In order to clear up any discrepancies in the simulation assumptions, Colleen Webb and Andrew Kanarek met with Ben Bolker to discuss the algorithm for the stochastic continuous time process. Ben was tremendously helpful as we resolved the main technical issues.

Publication in prep: Kanarek, Webb, & Holt. Allee Effects and Clustering Dynamics as Determinants for Invasion Success.

Modeling techniques for capturing the complexities of genetic architecture
Main Goal: To discuss methods for investigating recombination and mutation for the evolution of small founder populations

Andrew Kanarek, Colleen Webb, Bob Holt, and Mike Barfield discussed Andrew’s results for a multi-locus additive model that suggests that recombination plays a stronger role in maintaining or enhancing genetic variation than mutation or drift. We considered how the clustering effects will impact variation and relatedness, and brain-stormed mate finding strategies. This lead to considerations for an extension of the model to look at the evolution of dispersal and heteromyopia. Additionally, the issue arose for how to initialize the genetic variance according to the Stochastic House of Cards in the continuous time model. We worked on understanding some details to develop a more complex gene regulation network, and plan to spend time collaborating on this in the future.


Event: Research Exchange

When: 14-April 2009 until 16-April 2009

Where: University of Florida

Directions: Click here

Contact: Andrew Kanarek (andrew.kanarek@gmail.com)

Attendees: Andrew Kanarek, Bob Holt, Mike Barfield, Sam Scheiner, Colleen Webb