Investigators of a turtle population study spanning 19 years reported major declines in capture rates of red-eared sliders (Trachemys scripta; 4.05 to 0.44) and Ouachita map turtles (Graptemys ouachitensis; 0.18 to 0.01) populations within Sequoyah National Wildlife Refuge in Vian, Oklahoma. Although capture rates of alligator snapping turtles (Macrochelys temminckii) collected in 2016 were comparable to those found in a 1997-2000 study (0.33 compared to 0.35), there was concern that the cause(s) of observed declines in smaller, shorter-lived turtle species could also impact alligator snapping turtle populations, and may not yet be apparent due to differences in life histories, such as longevity and age of sexual maturity.
Artificially constructed nests and trail cameras helped determine that nest predation, a common cause of turtle mortality is extremely high along six tributaries within the refuge (100%). Raccoons (Procyon lotor) were the most common nest predators, contributing to 71% of all nest predation. Alligator snapping turtle captures were higher in tributaries with higher nest predation suggesting that alligator snapping turtles may be contributing further to turtle mortalities. To alleviate the high rates of nest predation, the refuge should take action to manage common turtle nest predators, as well as investigate alligator snapping turtles as an additional turtle predator.
Environmental Science (MS)
Department, Program, or Center
Thomas H. Gosnell School of Life Sciences (COS)
Shipman, Alexandra M., "Investigation of nest predation as a cause of turtle population declines on the Sequoyah National Wildlife Refuge, Oklahoma" (2019). Thesis. Rochester Institute of Technology. Accessed from
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