New paper on Alligator Snapping Turtle movement by ARC program leader Ethan Kessler

Translocated Alligator Snapping Turtle with radio transmitter attached

A paper just out this week  in the Journal of Wildlife Management, “Movement behavior and passive dispersal of a reintroduced population of alligator snapping turtles” found that translocated AST behaved similarly to wild populations, and is largely passive. This can have conservation implications as reintroduced animals may be transported downstream by high flows.

 

Abstract

Maladaptive movement behavior is a leading cause of failure for reptile reintroductions, thus characterizing movement for translocated populations is important to project success. From 2014–2016 we radio-tracked 183 immature reintroduced alligator snapping turtles (Macrochelys temminckii) using very high frequency telemetry in a stream in southern Illinois, USA. We assessed environmental, temporal, morphometric, and microhabitat factors influencing movement, including post-release dispersal from reintroduction sites, movement probability, and step length. We used directional statistics to investigate the effects of precipitation and age on directional movement in the stream. Numerous factors influenced active movement, including ambient temperatures, time since release, use of log jams, turtle size, and age. Precipitation had an age-biased effect on movement. Directional analyses suggested that movement was largely passive as turtles were swept downstream with increased discharge. Overall, the behavior of reintroduced alligator snapping turtles was similar to that reported in wild populations. Passive downstream transport has implications for reintroduced and natural populations as a force for unintentional emigration in channelized streams under current conditions and future high flow regimes.

Read the full paper here.

Kessler, Ethan J. and Michael J. Dreslik. 2023. Movement behavior and passive dispersal of a reintroduced population of alligator snapping turtles. Journal of Wildlife Management. https://doi.org/10.1002/jwmg.22511

Radio telemetry used to improve environmental DNA use

Alligator Snapping Turtle

Environmental DNA (eDNA) is an emerging tool used to detect rare and difficult to detect species. A recent study by INHS PACE Lab herpetologists used radio telemetry to evaluate and improve the efficiency of this technique.

As part of a species reintroduction program, hatchling Alligator Snapping Turtles reared in captivity were tracked using radio telemetry to assess their survival. This work provided an ideal system for evaluating the efficacy and limitations of using eDNA to detect a bottom dwelling riverine turtle. At each radio location, water samples were collected as well as upstream and downstream of the turtle.

The researchers found that eDNA can be used to detect a benthic turtle species but that detection can be diminished by UV exposure from open canopy. This study shows the importance of continuing to use traditional methods such as radio telemetry to better understand the dynamics of eDNA in the environment.

 

Read the complete paper in Environmental DNA

Funding received to survey the Alligator Snapping Turtle

ARC Lab members Ethan J. Kessler and Michael J. Dreslik received funding from The Nature Conservancy, Indiana to conduct surveying for the Alligator Snapping Turtle (Macrochelys teminckii). The surveys will be a combined effort of trapping and eDNA sampling in the Patoka and White River watersheds. The project also includes some proof-of-concept work for eDNA work at the southern Illinois release site. Survey work will commence this summer through fall.