Patterns of extinction in prairie dog metapopulations: plague outbreaks follow El Nino events

Outbreaks of many vector-borne human diseases are broadly correlated with climatic variation, but evidence of similar fluctuations in disease in natural host populations is rare. Here, we use 21 years of monitoring of black-tailed prairie dog (Cynomys ludovicianus) colonies to demonstrate a link between extinctions of colonies attributed to plague (Yersinia pestis) and climatic fluctuations associated with El Ninì Southern Oscillation events that promote the growth of flea vector and rodent host populations. During epizootics, rates of extinction of the largest colonies (>16 ha) were nearly as high (>60%) as for the smallest ones (<3 ha), but only a third of intermediate-sized colonies were extirpated. The probability of extinction was influenced by the size and fate of adjacent colonies, but there was no predictable relationship between extinction probabilities and intercolony distance, indicating that spatial isolation does not reduce the vulnerability of colonies to plague. By causing sporadic extinctions of colonies, plague creates a metapopulation structure that has altered the dynamics of prairie dog colonies as they respond to a century of human persecution and habitat loss.