Extinction of Montane Populations of the Northern Leopard Frog (Rana pipiens) in Colorado

Abstract

Between 1973 and 1982, 9 populations of the northern leopard frog in the Red Feather Lakes region of Larimer County, Colorado, failed to reproduce. These failures all resulted in extinction of the populations. One area formerly supporting a population was recolonized in 1980, but no frogs were observed at any of the 9 sites in 1981 or 1982. Six of the populations were extinct because the breeding ponds dried up. The remaining populations were small enough to be susceptible to random events, but the nature of these events is unknown.