Reconstructing historical and contemporary disease dynamics: A case study using the California slender salamander

The fungal disease chytridiomycosis, caused by the pathogen Batrachochytrium dendrobatidis (Bd), has been implicated in the extirpation and extinction of amphibian species throughout the world. Recent Bd epizootics (i.e. epidemics in wildlife) have driven hundreds of species to near-extinction. Several species in California have been severely affected by Bd epizootics, but most work has focused on aquatic species. Our study focused on the most abundant and widespread terrestrial amphibian species in California, the California slender salamander, Batrachoseps attenuatus. This species is known to be infected by Bd, but little is known of its disease dynamics. We examined the effect of disease history on contemporary disease dynamics by combining retrospective tests for Bd emergence in museum specimens with contemporary field-collected infection data from the same locations. We found that Bd rapidly emerged in B. attenuatus and exhibited a non-linear pattern of spread throughout Northern C...