Terrestrial habitat preferences of adult arroyo southwestern toads

Using an external belt attachment system, we attached 1.8-g radiotransmitte rs to arroyo southwestern toads (Bufo microscaphus californicus). We tracke d 83 arroyo southwestern toads over an average period of 30.9 days (SD = 29 .0) in 1998, Male calling activity began at the study site on 6 March and e nded oil 29 July, We observed arroyo toad activity in upland habitat,, thro ughout the study. We examined the habitat preferences of arroyo toads by co mparing land cover within a minimum convex polygon estimate home range for each animal to the study site subarea where each toad occurred. We also com pared Substrate, vegetation, arid vegetation structure use to availability within each minimum convex polygon area. We found significant between-sex d ifferences in land use and vegetation-type preferences during the Study, bu t not for substrate or vegetation-structure preferences. Female arroyo sout hwestern toads preferred terrace and channel habitats to campground, agricu ltural, or upland habitats. During the breeding season, male arroyo southwe stern toad preference for channel habitats was significantly, greater than for all other habitat types. Toads preferred sands for but-rowing substrate , but no substrate type was preferred for surface activity. Differences in preference rank for vegetation type were weak. Male use of agricultural lan ds adjacent to breeding sites increased after the breeding season. Dense, t all vegetation structures were least preferred by arroyo southwestern toads for burrows. Arroyo southwestern toads ma forage and disperse through many vegetation types that are common in riparian and upland habitats of southe rn California.