Archive for September 11th, 2012

Cool new paper on ecological modeling

Earlier this year, three collaborators (Kenny Salau, Jacopo Baggio, and Marco Janssen) and I published a paper on modeling large-scale conservation.  Rather, the paper shows the results of an agent-based model of two species (predator and prey) that move across a simple fragmented landscape.  To put into simple English, we throw a bunch of predators (think lion) and prey (think impala) randomly across a landscape.  In this landscape, they can stay on a patch of habitat or move to another one.  The predators move if there aren’t enough prey around.  The prey move if there are too many predators or too many other prey.  We vary the ease of moving between the patches (their level of connectivity).  We also vary a number of other parameters of the model to see what happens if we look at different types of animals, different habitats, etc.

Basically what we see is that the goal isn’t only to continually increase connectivity.  This goes against some popular conservation thinking, where more is always better.  Instead, we know that there may be problems as we increase connectivity.  These problems may come from invasive species, the spread of disease, etc.  But they may also be internal dynamics from the system.  For instance, at high levels of connectivity, the populations of the separate patches may start to act like one big patch.  Local die-offs may lead to system-wide extinctions.  This is a central challenge to conservationists.

At this point, the model is purely ecological, but the broader research program is about how conservation planners and land managers interact to facilitate connectivity on a patchy landscape.  We have recently finished a paper that is under review that describes the interactions of a manager and how they can influence this system.  More on that in the future.

The current paper is:

Salau, Kehinde, Michael Schoon, Jacopo Baggio and Marco Janssen. 2012. “Varying Effects of Connectivity and Dispersal on Interacting Species Dynamics”, Ecological Modeling 242: 81-91.