Conserving an Endangered Toad in a Dynamic Landscape

Biodiversity is increasingly threatened by human alterations to the landscape. In southern California the arroyo toad (Anaxyrus californicus) is an endangered species whose range has been reduced by myriad landscape changes. The arroyo toad relies on erodible streamside habitats, in which pools form during high stream-flow events. Recent forest fires near San Diego have been costly, but may create habitat for this species by reducing streamside vegetation. I used biological information about the species, and existing distribution information to model suitable habitat following intense fires of 2003 in San Diego County. Although there are areas of Critical Habitat designated by the U.S. Fish and Wildlife where populations of the arroyo toad are known to exist, my habitat models illustrate that following the fires more habitat likely became available. It may be difficult to detect changes in habitat through time, and analyses of the National Landcover Datset showed only 2% of the area in potential suitable habitat appeared to have changed from 2001 to 2006, despite obvious differences in aerial imagery. It is important that conservation efforts make use of, and manage new habitat for endangered species when it becomes available.