The Wyoming toad (Anaxyrus baxteri) was found only in Albany County, Wyoming, USA. In 1993, the species was listed as extinct in the wild, but the toad survived in captivity. Multiple reintroduction attempts of the Wyoming toad between 1995 and 2012 had limited to no success. The species is still considered one of the rarest vertebrates in the world. Previous reintroductions of the Wyoming toad have typically utilized a hard release strategy for both translocation of larvae and adults. We examined two main questions. Can soft releasing toads improve establishment? How is the movement and behavior of reintroduced captive bred toads different from wild toads? In the summers of 2014 and 2015, we performed paired releases of four groups of captive bred adult toads at Mortenson Lake, Wyoming, USA. Captive bred toads were either hard released (n=12) or soft released (n=34) after acclimating in an outdoor enclosure for 14 days. One group of rare wild toads (n=12) was followed in 2015. All studied toads were fitted with a custom harness allowing for the external attachment of a harmonic tracking device. Toads were tracked for up to eight weeks to compare activity patterns, site fidelity, survival and spatial ecology.
Results/Conclusions
Compared to hard-released toads, the soft-released toads moved significantly shorter distances (p<0.05), had slower dispersal rates (p<0.05), and increased burrowing behavior (p<0.05). However, all captive reared toads had distinctly different spatial ecology compared to wild toads. A high proportion of hard released toads exhibited rapid dispersal behaviors within the first 72 hours of release. Sometimes moving into the dry, upland habitat and dying. Preliminary analysis indicates that the soft released toad’s behavior and movement is more similar to that of wild toads. We recommend soft releases for all reintroduced adult toads. The presence of cattle on the refuge in late 2015 appeared to change the movement ecology of released toad indicating an urgent need for more research into cattle-toad interactions. We will report on comparisons between wild and captive reared toads including mortality, activity patterns, and habitat use. The results have strong conservation management implications for multiple amphibian reintroduction programs.