JONES, D.J.; TRACY, C.R.; SIMANDLE, E.T.; University of Nevada, Reno; University of Nevada, Reno; University of Nevada, Reno: Oviposition Sites of the Amargosa Toad (Bufo Nelsoni)

The Amargosa toad (Bufo nelsoni) is an isolated endemic found in the Oasis Valley in Nye County, Nevada. In 1995, the Fish and Wildlife Service was petitioned to list the species as endangered, due to the presumed rarity of the toad. The focus of this research was to determine the habitat requirements for breeding and egg development. We surveyed for eggs at sites along the Amargosa River and nearby springs within the Oasis Valley. Where clutches were located, physical habitat parameters were measured and recorded. These included water depth, flow, and temperature, water chemistry, canopy and substrate composition. Toads began to lay eggs in February, and we continued to find clutches into July. Toads did not lay eggs randomly with respect to habitat parameters. Instead, it appears that the toads prefer to lay their eggs in shallow water with little or no flow and little to no emergent vegetation. The selection of these conditions may be adaptive and can offer several benefits to both the adult toads as well as the eggs. The results from this research should provide the foundation for habitat restoration and adaptive management for the species.