Population Status and Trends of the Ringed Sawback (Graptemys oculifera) in The Pearl River Drainage of Mississippi and Louisiana

<p>The Ringed Sawback (<em>Graptemys oculifera</em>) is primarily restricted to the Pearl River drainage of Mississippi and Louisiana. It was listed as a federally threatened species under the Endangered Species Act in 1986 largely due to extensive habitat modification and major habitat degradation throughout portions of its confined geographic range. Despite species protections, alterations to the structure and flow of the river have continued to threaten the drainage and likely the species’ recovery. Abundance levels, basking counts, and demographic parameters were measured from 2022-2024 at sites throughout the Pearl River drainage including five long-term monitoring sites. Population density estimates produced by two mark-resight models (Schnabel and NOREMARK) varied, where estimates were highest in the main-stem of the Pearl River below the Ross Barnett Reservoir and were lowest in tributaries and the West Pearl River Navigation Canal. Contrasting with previous capture-based studies, basking sex-ratios were male-biased at most sites. Body condition varied by sex, age-class, and site but was not associated with abundance, suggesting that the factors driving population density differ from those driving individual body condition. Thirty-four-year trend analysis found no significant trend at the drainage wide scale, though trends were detected at the site-specific scale and drainage wide mean density estimates displayed a 26.1% decrease from the earliest surveys. These results suggest that continued monitoring is warranted, and that monitoring efforts should be expanded in space and frequency to generate a more complete understanding of population trends.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2025

Author dc:creator

• Jaunsen, McAulay

Contributors dc:contributor

• Dr. Carl Qualls
• Dr. Luke Pearson
• Dr. Jake Schaefer

• Population status
• Mississippi and Louisiana
• Ringed Sawback
• Mark-Resight
• Other Animal Sciences
• Population Biology
• Zoology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/1134

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-2235