Tarleton Grad Student Leads Turtle Research Effort

An ongoing research project headed by Tarleton State University graduate student Doreen Mata has resulted in the radio-marking of 10 red-eared sliders on the Texas Parks and Wildlife’s McGillivray and Leona McKie Muse Wildlife Management Area near May, northeast of Lake Brownwood

red-eared sliders

Doreen’s research, titled “Population Dynamics and Community Assemblage of Semi-aquatic Turtles,” will identify and evaluate the community of semi-aquatic turtles and assess those populations in North Central Texas.

She hopes to obtain population and community responses in traditional mark-recapture versus environmental DNA.

“Understanding the movements of semi-aquatic turtles and their community dynamics will further help with management in areas where they are invasive species, as well as help conservation efforts of threatened or endangered turtle species,” she said.

In areas where they are invasive, semi-aquatic turtles can negatively impact native turtles, sometimes transmitting and damaging the native ecosystems they inhabit.

Doreen began traditional trapping and mark-recapture efforts in April 2021, taking body
measurements of each turtle trapped and marking the edge of its hard upper shell with a unique notch before releasing the animal.

Once a week she also took one-liter water samples and environmental variables — pH, total dissolved solids, ammonia, nitrates, nitrites and dissolved oxygen — to evaluate changes that possibly correlate to the turtle’s movements.

The Texas A&M AgriLife laboratory extracts eDNA to determine the presence or absence of the target species. Researchers then compare results from eDNA to traditional methods of mark-recapture and radio telemetry, focusing on the effectiveness of each technique.

Doreen initiated a pilot study using eDNA and radio telemetry in June.

Twenty-seven turtles will get radio transmitters, and Doreen will search for them every 24-72 hours during the study.

Preliminary data indicates that trapping may not be effectively capturing some of the rare turtles in the ecosystem. The hope is that eDNA could help identify species missed from the traditional approach.

Doreen’s research is supported by Texas Parks & Wildlife, a 2021 Tarleton Faculty-Student Internal Grant, the 2021 Presidential Excellence in Research Scholarship Grant, and internal funds from Dr. Heather Mathewson.

Dr. Mathewson, Dr. T. Wayne Schwertner and Dr. Hemanta Kafley serve on the research committee.

The project will continue through 2022.