First placed on the candidate list: 1997
Years waiting for protection: 7
Range: Arizona, Mexico (Sonora)
Habitat: desert wetlands

The Sonoyta mud turtle population has been reduced to a single reservoir in the United States. It has been listed as a candidate for protection under the Endangered Species Act since 1997, and is still waiting for endangered species protection. Since then, climatic changes in the Southwest have resulted in a series of low precipitation years which have had a drastic effect on mud turtle habitat.

The Sonoyta mud turtle is one of two recognized subspecies of the Sonoran mud turtle, an aquatic species which evolved in one of the driest regions of North America. It eats insects, crustaceans, snails, fish, frogs, and plants. Females bury their eggs on land, but even under ideal conditions, population growth is slow.

At the reservoir fed by Quitobaquito Springs an estimated population of several hundred Sonoyta mud turtles half a century ago has declined to around 130 today. The single U.S. turtle population is now isolated from the river in Mexico approximately one mile away. That means that if the population in the U.S. disappears, the reservoir at Quitobaquito Springs can not be recolonized with mud turtles from Mexico. The status of the Mexico populations of mud turtles is not known, but loss of flows, groundwater pumping, livestock grazing, and pesticide contamination may be affecting this population as well. Pesticide and heavy metal residues have also been found in Sonoyta mud turtles within the U.S. population, which may be a factor in their decline.

graphic Andrew Rodman ©2002
May 3, 2004
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