Ecology Letters (2010) 13: 1411–1418
Despite the central theme in ecology of evaluating determinants of species richness, little effort has been focused on parasites. Here, we developed a parasite diversity model based on known host associations with 29 North American carnivores to investigate the spatial heterogeneity of parasite richness, its relationship to carnivore richness, and how host composition and specificity influenced these patterns. Patterns in parasite species richness closely tracked carnivore species richness across space and this relationship was robust to deviations from the assumption that parasites match the distribution of their hosts. Because wide-ranging hosts disproportionately contributed to total and specialist parasite species richness, conservation programmes that focus on these common hosts may capture not only much of biological diversity, but also unwittingly sources of human diseases. We supply the first parasite diversity model to understand broad-scale patterns in species richness patterns for North American carnivores, which can inform both future parasite conservation and disease management.