Plague and prairie dogs: A stochastic patch occupancy model approach

Plague, caused by the bacterium Yersinia pestis, has high mortality rate in prairie dogs (up to 100%) on the Pawnee National Grassland (PNG) in Colorado, and it spreads rapidly during epizootics. If plague kills all prairie dogs within a town, what allows it to persist? Hypotheses include (i) Metapopulation structure allows the persistence of plague, and (ii) Exogenous infection periodically re-introduces plague other organisms such as small rodents and/or other areas such as nearby foothills.  Field observiations justify using a metapopulation model.  Thus, we used a modeling approach to investigate whether a metapopulation structure can allow the persistence of plague in prairie dogs.  The objectives of our study are to (1) characterize metapopulation dynamics explicitly, (2) estimate model parameters from field data, (3) use parameter estimates to simulate the system, and (4) make inferences based on simulation such as influence of exogenous infection, time until metapopulation extinction, and importance of particular patches.  In short, we found that a metapopulation structure can allow the persistence of prairie dogs and thereby, indirectly, the persistence of plague.