Urbanization and translocation disrupt the relationship between host density and parasite abundance

1.) The species interactions that structure natural communities are increasingly disrupted by radical habitat change resulting from the widespread processes of urbanization and species translocations. Although many species are disadvantaged by these changes, others thrive in these new environments, achieving densities exceeding those found in natural habitats. Often the same species that benefit from urbanization are successful invaders in introduced habitats, suggesting that similar processes promote these species in both environments.

2.) Both processes may especially benefit certain species by modifying their interactions with harmful parasites (“enemy release”). To detect such modifications, we first need to identify the mechanisms underlying host-parasite associations in natural populations, then test whether they are disrupted in cities and introduced habitats.

3.) We studied the interaction between the cane toad (Rhinella marina), a globally invasive species native to South...