Anaxyrus americanus

The genus Anaxyrus was split from Bufo by Frost et al. (2006). However, taxonomy within the genus Bufo remains controversial and many references still use the long-established Bufo.

The status of the nominal subspecies is far from clear, especially against the background of introgressive hybridization, which appears to be common along species boundaries (Frost 2017). Hybridizes with B. fowleri in several areas (Green 1984, Green and Parent 2003). Hybridizes also with B. hemiophrys in southeastern Manitoba and north-central U.S. (Green 1983, Green and Pustowka 1997). Sanders (1987) regarded populations in the James Bay region, Canada, as a distinct species, B. copei; other authors have treated copei as a subspecies of B. americanus or as unworthy of any taxonomic recognition. Masta et al. (2002) provided evidence that suggests that A. a. charlesmithi may be a distinct species. Fontenot, Makowsky, and Chippindale (2011) discussed hybridization with eastern members of the Anaxyrus americanus group and treated Anaxyrus charlesmithi as a distinct species without discussion. See also Fouquette and Dubois (2014) and Dodd (2013) for discussion on hybridization.

This species has a large range in the eastern U.S. and Canada. The population is abundant and widespread. Threats include habitat loss, road mortality, and infection with the chytrid fungus.

This species occurs across the eastern United States and Canada. The range extends from Labrador, Hudson Bay area, and central Manitoba south to northern Texas, Louisiana, central Alabama, northern Georgia, and North Carolina (Dodd Jr. 2023). It is absent from most of the Southeastern Coastal Plain.

Represented by many and/or large occurrences throughout most of the range.

Dispersing juveniles tend to avoid open canopy habitat, so deforestation and fragmentation likely reduce dispersal rates between local populations and could negatively impact population persistence in altered landscapes (Rothermal and Semlitsch 2002). Chytrid fungus (Batrachochytrium dendrobatidis) is most severe for metamorphs, generally reducing survival and growth (Dodd Jr. 2023). Roads can also cause mortality from vehicle strikes during dispersal to and from breeding sites (Dodd Jr. 2023).