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.