This species occurs from south-central Arizona in the USA (Sullivan et al. 1996), south to south-central Sonora, Mexico. Known from elevations from 150-900m asl (Bogert, 1962; Stebbins, 1985; Sullivan et al., 1996). In Arizona, it is known from Organ Pipe Cactus National Monument east across the Tohono O'odham Reservation to San Xavier Mission, throughout Pima County and north to Waterman Wash near Mobile, Arizona. It also occurs in Vekol Valley (Arizona Game and Fish Department 1992, Jones et al., 1983). Occurs on forty documented sites in Arizona (Schwartz pers. comm., 1997). Hulse (1978) mapped 17 collection sites in Mexico. Sullivan et al. (1996) mapped 51 historical collection locations. During a 1993-1994 Arizona survey, the species was relocated at or near all historical locations surveyed and at additional new sites for a total of 25 collection localities (Sullivan et al. 1996).
Habitat and Ecology
This species inhabits semi-arid plains, mesquite grassland and creosote bush desert. Well drilling and irrigation may create suitable habitat (Hulse 1978). Breeding has been observed in temporary pools formed in roadside ditches, rainwater sumps, cattle tanks, and wash bottoms (Hulse, 1978; Stebbins, 1985; Sullivan et al., 1996). Inactive for more than 10 months each year, emerging only following intense rainfall events during the summer monsoon season (Sullivan et al. 1996).
The total adult population size is unknown but fairly common and probably stable. It is less common on the periphery of its range, near Organ Pipe Cactus National Monument in the west, near Mobile in the north, and in the Altar Valley in the east (Sullivan et al. 1996). The species is difficult to survey due to limited property access (most of Arizona range on Tohono O'odham Reservation, access denied), secretive nature (B. Sullivan pers. comm., 1997), and long inactive period. Ashton (1976) reported that Arizona populations were stable (see Bury et al. 1980). Recent documentation (1993-1994) at most historical sites and additional new localities in Arizona suggests no widespread declines (Sullivan et al. 1996). However, there is no solid population information available to assess trends (B. Sullivan pers. comm., 1997). No information available for Mexico.
Stebbins (1975) considered over collecting the chief threat (see Bury et al. 1980). It occurs in large aggregations during breeding events. Over collecting of females (for the pet trade or research) at this time could be detrimental but is not currently a problem (B. Sullivan pers. comm., 1997). It naturally hybridises with B. punctatus but given the apparent rareness of hybrids, it is unlikely that this presents a significant concern for the population status (Sullivan et al. 1996). The effects of grazing practices or agriculture are unknown.
Protected at Sonoran Desert and Organ Pipe Cactus National Monuments and the Buenos Aires National Wildlife Refuge. Sonoran green toads are ranked at G3G4 and S4 by the State of Arizona meaning the species is apparently secure, but is uncommon in parts of its range. Collection of Sonoran green toads in Arizona is limited to 10 toads/yr with a fishing license. This species is protected by Mexican law under the "Special Protection" category (Pr).
Red List Status
Least Concern (LC)
Listed as Least Concern in view of its relatively wide distribution, tolerance of a degree of habitat modification, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.
Geoffrey Hammerson, Georgina Santos-Barrera, Sean Blomquist 2004. Anaxyrus retiformis. The IUCN Red List of Threatened Species 2004: e.T3173A9656360. http://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T3173A9656360.en