Herpetology Notes, volume 14: 1043-1049 (2021) (published online on 03 August 2021) Movements of Sternotherus minor (Testudines: Kinosternidae) in a Central Florida Spring-run Stephen J. Enders1,2, Andrew S. Weber1,2,3, Brian P. Butterfield4, Andrew Walde1, Ayla Ross5, Brian Hauge1,6, Tabitha Hootman1, Wayne Osborne1,7, and Eric C. Munscher1,8,* Abstract. Movement patterns of turtles can vary depending on natural and anthropogenic pressures and can correlate with sex, size, food availability, reproduction, territorial behaviour, seasonality, location, and habitat. We analysed the movements of Loggerhead Musk Turtles (Sternotherus minor) based on body size, sex, time between captures, and capture segments in Wekiwa Springs State Park, Florida, United States of America, over a period of six years using capture, mark, recapture sampling. To record turtle movements, we divided the 1 km spring-run into ten 100 m long segments. Individuals with two or more data entries of segment locations were used for this study, with each paired capture/recapture constituting one movement event. A total of 133 movement events were recorded, and the majority, 60.9% (81), showed no inter-segment movement; 88.0% (117) of the movement events were one segment or less, a maximum distance of 200 m. Using canonical discriminant analysis we found no relationship between the movement of S. minor and carapace length, sex, time between captures, and capture segments. More research is needed into the movement ecology of this species. Based on the observed paucity of movements, future work may focus around dividing the spring-run into shorter segments. The potential for territoriality and dominance hierarchies should also be examined. We strongly recommend the use of radio telemetry to learn more about the nuanced movements of this small turtle. Keywords. Loggerhead Musk Turtle, Sternotherus minor, movement, spring-run Introduction environment. There are many natural reasons for movement of an animal, such as food and water Movement is a core behaviour necessary to the availability, seasonal shifts, temperature regulation, and survival of many animal species. For the purposes reproduction (Heape, 1931). Anthropogenic factors, of this research, we define movement as a change such as artificial light, noise, and development are also in position of the entire body of an organism in the known to influence animal movement (Thums et al., 2016; Cayuela et al., 2020). The same triggers, both natural and human-induced, have also been shown to 1 Turtle Survival Alliance, 1030 Jenkins Road, Suite D, motivate movement in turtles (Cagle, 1944). Studies Charleston, South Carolina 29407, USA. have shown a wide variation in magnitude and types 2 TheTurtleRoom, P.O. Box 521, Lititz, Pennsylvania 17543, of chelonian movements which include: sea turtles USA. that can travel thousands of kilometres annually (Hays 3 National Park Service, 274 River Road, Beach Lake, Pennsylvania 18405, USA. and Scott, 2013); Mojave Desert Tortoises (Gopherus 4 Freed-Hardeman University, 158 East Main Street, Henderson, agassizii [Cooper, 1861]) with home ranges between Tennessee 38340, USA. 5-236 ha (Harless et al., 2009, 2010); Box Turtles 5 Department of Biology, Indiana University of Pennsylvania, (Terrapene spp.) with a home range of ca. 4 ha (Habeck Indiana, Pennsylvania 15705, USA. et al., 2019); Smooth Softshell Turtles (Apalone mutica 6 Department of Biology, Peninsula College, 1502 East [LeSueur, 1827]) with a linear home range of ca. 500 Lauridsen Boulevard, Port Angeles, Washington 98362, m (Plummer and Shirer, 1975); and Florida Red-bellied USA. 7 Pine Ridge High School, 926 Howland Boulevard, Deltona, Cooters (Pseudemys nelsoni Carr, 1938) with a home Florida 32738, USA. range of only 120 m, despite the large size of the turtle 8 SWCA Environmental Consultants, 10245 West Little York (Kramer, 1995). These species-specific movements are Road, Suite 600, Houston, Texas 77040, USA. important characteristics to take into account for further * Corresponding author. E-mail: [email protected] research activities or for effective, targeted conservation © 2021 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0. measures. 1044 Stephen J. Enders et al. Despite the importance of the study of movement S. minor movements in a spring-run system, and lead patterns for chelonian conservation and survival, to a better understanding of the requirements of the many species are still relatively understudied (Lovich species. and Ennen, 2013; Munscher et al., 2020), including those within the genus Sternotherus (musk turtles), Materials and Methods with the possible exception of the Common Musk Field Site. This study took place in Wekiwa Springs Turtle (Sternotherus odoratus [Latreille in Sonnini Run (28.714°N, 81.453°W; WGS 84) within Wekiwa and Latreille, 1801]). Most movement and home range Springs State Park in Orange and Seminole Counties, research on Sternotherus has focused on the S. odoratus in Florida, as part of a larger monitoring effort (see with a few studies on the Razor-backed Musk Turtle (S. Munscher et al., 2013, 2015a, b, 2020; Walde et al., carinatus [Gray, 1856]) and the Stripe-necked Musk 2016). Wekiwa Springs Run is a 1 km section of spring- Turtle (S. peltifer Smith and Glass, 1947), the latter was run habitat connecting the main lagoon and Rock Springs formerly considered a subspecies of the Loggerhead Run to the Wekiva River. We divided the spring-run into Musk Turtle (S. minor [Agassiz, 1857]). Examination ten 100 m long segments (Fig. 1). of the movement and home range of S. odoratus has Data Collection. We sampled from August 2010 to shown it to typically exhibit limited movement in lentic March 2016, twice per year (spring and summer) for (Andres and Chambers, 2006; Holinka et al., 2003; a time period of 3–5 days. Loggerhead Musk Turtles Smar and Chambers, 2005) as well as lotic habitats (Fig. 2) were captured via hand while snorkelling and (Mahmoud, 1969; Belleau, 2008; Wilhelm and Plummer, placed in containers marked with the number of the 2012). Sternotherus carinatus also demonstrates corresponding segment of capture. Snorkelling occurred limited movements, with a preference for lotic habitats intermittently during daylight hours. Captured turtles (Mahmoud, 1969; Kavanagh and Kwiatkowski, 2016). were marked using a variation of the Cagle (1939) While home range of the S. peltifer showed that most method. Turtles with straight-line maximum carapace individuals used multiple habitats within their home length (CLmax) ≥ 70 mm were implanted with 8.5 range (Ennen and Scott, 2013) and displayed site mm passive integrated transponders (BIOMARK, fidelity within daily movement patterns (Ennen and Boise, Idaho, USA) containing unique identification Scott, 2008). In the case of S. minor, to the best of our numbers. Turtles were sexed using secondary sexual knowledge, this is the first study describing movement characteristics of tail size and cloacal vent location. patterns or home ranges of S. minor. Only turtles less than 50 mm CLmax were coded as Sternotherus minor is a small musk turtle, with juvenile if sex could not be otherwise determined. If we similarly sized sexes, that ranges throughout most of coded an individual as juvenile upon initial capture, but Georgia south of the Appalachian Mountains, across sex could be determined at recapture, the sex variable much of the northern part of Florida, and far southeastern was recoded with the recapture sex. Alabama (Ernst and Lovich, 2009). In Florida, S. minor Analysis. A “movement event” was defined as the occurs in a variety of habitats including freshwater distance moved, in segments (used as a unit), between springs, spring-runs, lagoons, lakes, ponds, and river two capture events of an individual. If the variable days systems (Zappalorti and Iverson, 2006; Reidle et al., between captures was less than five, those events were 2016; Munscher et al., 2020) showing preference for removed. This left us with 133 movement events with lotic habitats (Tinkle, 1958; Zappalorti and Iverson, the shortest time between capture at 225 days and the 2006). longest at 715 days. Florida is high in turtle diversity, second to only Canonical discriminant analysis was chosen because Alabama worldwide, and spring-run systems are known we desired a categorical response (did the turtle move to provide habitat for a variety of species, making them segments or not?) with both categorical and continuous well-suited for sustained research efforts (Meylan et al., input variables. Variables examined included: days 1992; Mittermeier et al., 2015; Munscher et al., 2020). between captures (days), sex, carapace length at initial Populations of Sternotherus have been sampled as part capture (CL1), carapace length at recapture (CL2), of a long-term, multispecies monitoring effort over the change in carapace length (CL change), segment of last 20 years by the Turtle Survival Alliance–North capture (CS1–9), and segment of recapture (RCS1– American Freshwater Turtle Research Group (Munscher 9). Statistical tests were performed using Statistical et al., 2020). The purpose of this study is to characterise Analysis Systems software (SAS Institute, 2018). Movements of Sternotherus minor in a Central Florida Spring-run 1045 Figure 1. A map of a section of Wekiwa Springs State Park, showing the main lagoon and Wekiwa Springs Run divided into ten segments, each representing a scale of 100 m long (LABINS, 2019) Results Of the total movement events sampled (n = 133), 60.9% (n = 81) involved a distance of zero segments (Table 1) and 88.0% (n = 117) involved a distance of zero or one segments, meaning that these movements were less than 200 meters in stream length (Table 1). The longest male movement was seven segments, and the longest female movement was five segments (Table 2). The F-value of the resulting discriminant function was 1.31 (df: 22, 106) with a p-value of 0.1848. Therefore, no single variable nor function involving any combination of the examined variables explained the observed movement patterns.