Relict Leopard Frog

An adult relict leopard frog basks in the cool water of Tassi Spring.

NPS/ Todd Miller

Thought to be extinct in the 1950s, the relict leopard frog (Lithobates onca) was rediscovered along seven areas of its historic range, the Virgin and Muddy rivers, in the 1990s. Permanent streams, springs and spring-fed wetlands are in short supply in the arid desert making the frog not only vulnerable to changes outside of its habitat but also to climate change. Urban development, degradation of habitat from grazing, vegetation encroachment and competition with non-native species have also likely played a role in the decline of relict leopard frogs leading them to be listed as a species of special concern in Arizona.

In 2005, a team of specialists was formed to oversee the conservation of relict leopard frogs. The team began a translocation program to establish experimental populations at suitable locations. The remoteness of Tassi Spring on Parashant National Monument has thus far proved to be one such candidate. The spring's low elevation, diverse vegetation, 74°F water temperature, and lack of non-native competition make the spring a viable habitat for the frogs. In 2016, 175 frogs were introduced to the spring. Two years later, in 2018, evidence of a reproducing population was observed helping to lead the way to recovery of this fragile species.