Predator effects on disease outbreaks in a patchy stochastic environment

Background/Question/Methods

In the past decade, many studies have focused on pathogen-host interactions in their community context, taking into account the effect of predation on pathogen-host dynamics. These studies have revealed that the effect of a predator on the host community strongly depends on whether or not the host can acquire immunity to the pathogen. In cases where it does not gain immunity, the predator can decrease pathogen prevalence (Hall et al., 2005). However, when there is immunity acquisition, predation can lead to pathogen outbreaks in the host population (Roy and Holt, 2007; Moore et al., 2010). We here extend this approach to a metacommunity context, examining extinction dynamics in a spatially explicit stochastic model (Alonso and McKane, 2002). We first analyze simple host-pathogen interactions in a spatial context and then examine the effects of a specialist predator on the dynamics of these interactions. We evaluate host extinction probabilities and identify conditions under which the pathogen is suppressed or made to fluctuate in the host population.

Results/Conclusions

Our study suggests that changes in habitat size, availability and connectivity – as could be expected to occur under climate change – significantly affect host-pathogen dynamics. Our methods allow for a careful characterization of extinction thresholds for most of these parameters. Our results are particularly relevant for conservation biology and biological control of agricultural pests.