An update on our Spotted Turtle research program

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A Spotted Turtle from southeastern Georgia – Ben Stegenga

The Orianne Society has now been working on Spotted Turtle research projects since 2014, and they have become one of our primary focal species in recent years. We have completed survey work and research projects in Georgia, Florida, and South Carolina, with a new project soon starting in Vermont. We have now published research projects looking at several aspects of Spotted Turtle ecology in the southeastern U.S., including detailing the distribution and status in Georgia (Stevenson et al. 2015), movement and spatial ecology (Chandler et al. 2019), thermal ecology (Chandler et al. 2020), and, most recently, reproductive ecology of southern populations (Chandler et al. 2022). Check out some of my other posts on these projects:

In addition to these research projects, we have also been actively engaged with the Spotted Turtle Working Group since 2018, which brings together a large group of partners from across the species’ distribution to work on Spotted Turtle conservation projects. This group has hosted a meeting for turtle biologists to discuss conservation issues for Spotted, Blanding’s, and Wood Turtles and is in the final stages of preparing a range-wide conservation plan for Spotted Turtles. This impressive document covers the ecology of Spotted Turtles, the threats that the species faces, and some goals for conservation and management actions to ensure Spotted Turtle populations persist into the future. As part of this effort, we traveled all over the southeast in search of undocumented Spotted Turtle populations. This work was exhausting (Spotted Turtles in the southeast are incredibly difficult to find, even at known sites). However, over three years of surveying, we managed to document multiple new populations on public lands across the three states.

Technicians David Hutto and Trina Wantman collecting data as part of a Spotted Turtle survey – Houston Chandler

The other component of our Spotted Turtle work has been long-term population monitoring at two focal sites in Georgia. It’s been almost three years since I last wrote about this work, so it seems like a good time for an update. We have continued to trap turtles in these two populations each spring, marking new individuals and seeing many old friends. It is remarkable how reliable some individuals are over time, showing up in more or less the same spot each year. Several individuals have been captured in every year of the study (and usually multiple times each year), while others have only been seen a few times, often with multi-year gaps in between capture events. Where do they go the rest of the time?

A Spotted Turtle in a characteristic bottomland swamp habitat from southern Georgia – Ben Stegenga

To date, we have marked a total of 107 turtles at the site with the larger population, accounting for 712 total capture events in 9 years of survey work. Of these 712 capture events, seven individuals have accounted for an incredible 212 of them (30%). Old friends indeed! At the other site, which has a noticeably smaller population, we have marked 50 individuals in 8 years of survey work (247 total capture events). It is clear that these two habitats function very differently even though they are only 145 km apart. The site with the smaller population has less wetland area overall and is more ephemeral, forcing turtles to spend large amount of time in terrestrial habitat each year. Interestingly, as part of expanded survey efforts, we have documented Spotted Turtles in multiple wetlands on this property (separated by hundreds of meters), and it is likely that these wetlands are connected to some extent by occasional long-distance movements.

Plots of our Spotted Turtle mark-recapture survey history at two sites in Georgia. Bars represent yearly captures split between new captures and recaptures, and the solid line represents the total number of turtles marked at that sites. – Houston Chandler

So where does our Spotted Turtle work go from here? We plan to continue annual monitoring of the populations at our two focal sites with the ultimate goal of eventually being able to better understand population dynamics in these southern populations. Turtle’s long life spans makes it challenging to accurately model populations through time and necessitates long-term datasets, which we have begun building. This will ultimately allow us to examine whether or not these Spotted Turtle populations are stable and likely to persist as their environment changes. More broadly, there is interest among conservation partners for more survey work in the southeast, and that is one of the highlighted needs in the conservation plan that I mentioned above. There are also opportunities to answer other interesting questions surrounding Spotted Turtle ecology. For example, Spotted Turtles have temperature dependent sex determination, and there is the potential for climate change to impact the sex ratios of turtle populations. Targeted research could help illuminate what, if anything, could be done to manage these types of threats. Finally, our previous survey work identified multiple populations that have been, and are being, impacted by significant wetland alteration (mainly ditching and draining). Many of these populations are on public lands, and there are opportunities to do on-the-ground wetland restoration work at some of these sites to improve the habitat for Spotted Turtles.

Juvenile Spotted Turtle from Georgia – Houston Chandler

Overall, Spotted Turtles have been an incredible animal to work with over the last six years, and I am excited to continue our focus on this diminutive but beautiful turtle for years to come.

Literature Cited

Chandler, H. C., B. S. Stegenga, and D. J. Stevenson. 2019. Movement and space use in southern populations of Spotted Turtles (Clemmys guttata). Southeastern Naturalist 18:602–618.

Chandler, H. C., B. S. Stegenga, and D. J. Stevenson. 2020. Thermal ecology of Spotted Turtles (Clemmys guttata) in two southern populations. Copeia 108:737–745.

Chandler, H.C., B.S. Stegenga, and J.D. Mays. 2022. Compensating for small body size: The reproductive ecology of southern Spotted Turtle (Clemmys guttata) populations. Ichthyology & Herpetology 110:268–277.

Stevenson, D. J., J. B. Jensen, E. A. Schlimm, and M. Moore. 2015. The distribution, habitat use, activity, and status of the Spotted Turtle (Clemmys guttata) in Georgia. Chelonian Conservation and Biology 14:136–142.