Department, experts study threatened turtle species

By Darren Vaughan, Communications Director

The Rio Grande cooter is one of New Mexico’s 10 native turtle species, yet it has received relatively little scientific attention compared to many other North American turtles.

However, thanks to the efforts of New Mexico Department of Wildlife experts, in conjunction with experts from across the country, understanding of this state threatened species is improving. This summer, surveys will take place to better understand the status of the Rio Grande cooter in New Mexico.

“Like any native organism, turtles are intrinsic to their ecosystems as predators, prey, scavengers and other ecosystem services,” Department herpetologist Leland Pierce said. “Were this species to disappear, its absence would, over time, affect its native ecosystem as a whole.”

The Rio Grande cooter is native to the Rio Grande/Rio Bravo watershed in New Mexico and Texas and can also be found in several northern Mexican states. According to the United States Fish and Wildlife Service (USFWS), it was first described as a subspecies of the river cooter in 1952 based off a specimen from Coahuila. It was recognized as its own distinct species — receiving the scientific name Psedemys gorzugi — in 1990. It is currently listed as threatened under the New Mexico Wildlife Conservation Act and is considered an SGCN under the 2025 State Wildlife Action Plan for New Mexico.

In its December 2021 Species Status Assessment Report, which Pierce participated in on behalf of the Department, USFWS identified declining water quantity and degraded water quality as the most significant threats to the Rio Grande cooter. Human impacts on springs, streams, rivers and groundwater sources have altered or reduced available habitat, while climate change has further affected both surface‑ and groundwater availability.

The full report can be viewed on USFWS’ website.

The Department partnered with Dr. Ivana Mali, who spent seven years conducting intensive population surveys in the Black River in Eddy County . This river is home to the only robust Rio Grande cooter population in New Mexico.

The Rio Grande cooter faces numerous challenges beyond environmental pressures.

“Habitat loss is the primary concern, including water drawdowns, declining water levels due to drought and alterations to habitat structure,” Pierce said. “Pollution is also a concern for any aquatic organism. The species has been illegally collected in other states. Climate change could also affect the species.”

Much of the research has been supported by grants from the Department’s Share with Wildlife program. Dr. Mali and her research team have also studied the species’ reproductive timing, as well as its diet and distribution, providing valuable data for conservation planning.

Dr. Mali will return to New Mexico this summer to conduct additional studies, providing a five-year update on her 2021 work. Data gathered will help determine next steps for the continued protection of this species.

“This is very labor-intensive and requires a certain skill set that is not easily repeated,” Pierce said of the study. “The data will go to our population models and will inform us if we need to do things like assurance populations. A loss of that population would significantly impact the long-term resilience of the species in New Mexico.”

The Share with Wildlife program funds studies for species such as the Rio Grande cooter that do not receive funding from any other source. For more information about the program, visit the Share with Wildlife page on the Department’s website.

For more information about the Rio Grande cooter and other threatened or endangered species in New Mexico, visit the New Mexico Wildlife Species Information page.