The endangered listing of the Sonoyta mud turtle

Authors: Cat Crawford, Doug Duncan, Hayley Dikeman

Year: 2017 (xlix)

Abstract

The Sonoyta mud turtle is an isolated endemic subspecies of the Sonora mud turtle in the Rio Sonoyta basin in southwestern Arizona and northwestern Sonora, an extremely arid environment Historically, they were found in cienegas and streams that maintain water all year Currently they are found in spring-fed and wastewater fed ponds and streams Historically, there were likely four populations of the turtle?three in Sonora and one in Organ Pipe Cactus National Monument These populations were likely hydrologically connected, at least periodically, allowing for immigration and emigration between the populations Currently, one population in Mexico is extirpated due to loss of water, the other two in Mexico are extant but their range is greatly reduced due to water loss, and the US population is extant Two additional populations were found in 2002?one in wastewater ponds and one in Quitovac These five populations occupy only about 8 to 20% of the historical range The most significant historical and current stressor for the turtle is the loss of aquatic and riparian habitat due to groundwater pumping and long-term drought and climate change All five populations are isolated from each other and each population is supported by very small amounts of aquatic habitat A single stochastic event such as dredging or a year with little precipitation could eliminate an entire population The high risk of extirpation of these populations is a result of low levels of resiliency, redundancy, and representation Overall, these low levels of resiliency, redundancy, and representation result in the Sonoyta mud turtle having a high risk of extinction, and thus has been listed as endangered