The Behavioral Responses of Eastern Box (Terrapene c. carolina), Midland Painted Turtles (Chrysemys picta marginata), and Stinkpots (Sternotherus odoratus) to Roads and Vehicles on a Simulated Divided Highway

Aaron C. Gooley1, Jayme L. Waldron2, and Thomas K. Pauley1. Marshall University1, University of South Carolina2. Abstract 88% Road mortality has been identified as a major threat to many species; however, response to passing vehicles has never been investigated in turtles. To investigate these factors, Midland Painted Turtles (Chrysemys picta marginata), Eastern Box Turtles (Terrapene 33% c. carolina), and Stinkpots (Sternotherus odoratus) were collected Stopped % 22% and placed in a release box on the side of a closed road with an active road running parallel to it 26 m away. Turtles were released via n=32 n=27 n=15 a pulley-operated door facing the road, and their actions videotaped by an observer in a nearby blind. A vehicle was driven past crossing Eastern Box Turtles Midland Painted Stinkpots turtles on the closed road to simulate passing traffic in the adjoining Turtles lane. Resulting videos were used to determine the frequency of Figure 1. The percent of passing opposing lane vehicles that responses and length of stops due to passing vehicles. Following each turtle species responded to by stopping for >2 seconds. trials, turtles were released at the original point of capture. Eastern Methods Box Turtles stopped due to the stimulus of opposing lane vehicles more than either Stinkpots or Midland Painted Turtles, and when From May through September of 2009 Midland Painted stopped, they remained stationary for a greater time. All species Turtles, Eastern Box Turtles, and Stinkpots were collected Results reacted to the passing adjoining lane vehicle by stopping on the from Beech Fork State Park, Greenbottom Wildlife road. These results indicate that Eastern Box Turtles are at greater Management Area (Cabell, Mason, and Wayne counties), and Eastern Box Turtles responded to opposing lane vehicles by stopping a greater risk of mortality when crossing divided highways than either other West Virginia locations using hoop-net traps and visual percentage of the time and for longer time periods than either Stinkpots or Stinkpots or Midland Painted Turtles due to a higher stop response searches. Each collected turtle was housed individually in an Midland Painted Turtles (Fig. 1, Fig. 2). Eastern Box Turtles stop times per rate to opposing lane vehicles. opaque tub before and after its trial. For each trial, a turtle passing opposing lane vehicle were statistically different from both Midland was placed in a release box on a random side of the closed Painted Turtles and Stinkpots (P<0.05, one-way ANOVA). However, Midland road and released via a pulley-operated door facing the road Painted Turtles did not differ significantly from Stinkpots (P>0.05). All species by an observer in a nearby blind. The release box was placed reacted to a passing adjoining lane vehicle by stopping on the road; however, 10 cm from the edge of the pavement and the blind was Eastern Box Turtles and Stinkpots averaged more time stopped than Midland Introduction erected in the strip of tall grass and forbs 10 m from the Painted Turtles (104 sec n=5, 127 sec n=4, 45 sec n=13 respectively). Differences release box. Turtles that proceeded out of the release box were significant between Eastern Box Turtles and Midland Painted Turtles and onto the road were videotaped. A vehicle was driven past (P<0.05) and between Midland Painted Turtles and Stinkpots (P<0.05), but not Road mortality has been identified as a major threat to many turtle a portion of the crossing turtles to simulate passing traffic in between Eastern Box Turtles and Stinkpots (P>0.05, One-Way ANOVA with log10 species (Beaudry et al. 2008). Some highways are virtually the adjoining lane. The vehicle was signaled to drive past by transformation of time ). impassable to turtles (Aresco 2005b) and may act as geographic the observer when the turtle was partway across the first barriers to turtle populations, isolating them and lowering their lane. The signal was timed, based on the turtle’s speed and chances of long-term survival. Multiple studies have shown the position, to allow the vehicle to drive past at 40 to 56 kph skewing of semi-aquatic turtle populations toward a male-biased sex without posing any danger to it. Videos were used to ratio and have implicated female road mortality as the cause (Aresco 24 determine the percent of time each turtle species responded 2005a, Gibbs and Steen 2005, Steen and Gibbs 2004, Steen et. al. to a passing opposing lane vehicle by stopping and to 2006). A formula has been created to model the probability of a turtle estimate the length of time a single passing vehicle causes being killed when crossing a road (Gibbs and Shriver 2002, Beaudry each species to stop. A turtle was considered to have 11 11 et al. 2008, Beaudry et al. 2010). This formula assumes that turtles stopped if it ceased to walk for over 2 seconds. Percent of walk straight across a road at a set speed without stopping because Stopped Seconds time each turtle species responded to a passing adjoining response to passing vehicles and general behavior while crossing lane vehicle by stopping was determined by dividing the total roads has never been investigated in turtles. We followed Andrews’ n=28 n=6 n=5 times stopped as a result of an active road vehicle by the total (2004) study on snakes to investigate road crossing behavior in number of active road vehicles which passed with the Eastern Box Turtles Midland Painted Stinkpots Midland Painted Turtles, Eastern Box Turtles, and Stinkpots; exception of vehicles which passed while a turtle was Turtles specifically time spent stopped in response to passing vehicles on a stopped. Average stop time per passing active road vehicle divided highway. Figure 2. Average stop time per passing opposing was calculated for each specimen by dividing the total time lane vehicle by species. stopped in response to active road vehicles by the total number of vehicles that caused the turtle to stop or that passed while the turtle was stopped. Following trials, turtles were released at the original point of capture. Conclusions Study Site These results indicate that Eastern Box Turtles spend more time stopped on Trials were conducted on the Road to Nowhere at Beech Fork State the road when crossing divided highways and roads in general than Stinkpots Park, Cabell County, WV. The Road to Nowhere is a 6-meter-wide or Midland Painted Turtles and are thus at greater risk of vehicular-induced paved road that is closed to unauthorized vehicular traffic. An active mortality. This may partially explain the high number of Eastern two-lane road runs parallel to it approximately 26 m to the south. The road mortalities observed in West Virginia compared to other turtle species active road is slightly elevated and traffic is clearly visible from the (Pauley, unpublished data). surface of the Road to Nowhere. A 1.2-1.5 m mowed, grass strip bordered either side of the Road to Nowhere. A strip of tall grasses and forbs was located just beyond the mowed grass, and was Works Cited followed by a lower seasonally wet area dominated by ferns, grasses,

and scattered bushes and trees. The close proximity of the active Andrews, K. M. 2004. Interspecific comparisons of behavioral responses of southeastern snakes to roads. Masters thesis University of Georgia, Athens. Aresco, M.J., 2005a. The effect of sex-specific terrestrial movements and roads on the sex ratio of freshwater turtles. Biological Conservation 123:37–44. road to the Road to Nowhere provided a suitable location to simulate Aresco, M.J., 2005b. Mitigation measures to reduce highway mortality of turtles and other herpetofauna at a north lake. Journal of Wildlife Management 69:549–560. a divided highway. Vehicles on the active road represented opposing Beaudry, F., P. G. deMaynadier, M. L. Hunter Jr. 2008. Identifying road mortality threat at multiple spatial scales for semi-aquatic turtles. Biological Conservation 141:2550-2563. Beaudry, F., P. G. deMaynadier, M. L. Hunter Jr. 2010. Identifying Hot Moments in Road-Mortality Risk for Freshwater Turtles. Journal of Wildlife Management 74:152-158. lane traffic. Gibbs, J. P., and D. A. Steen. 2005. Trends in sex ratios of turtles in the : implications of road mortality. Conservation Biology Vol. 19 No. 2:552-556. Gibbs, J. P., and W. G. Shriver. 2002. Estimating the effects of road mortality on turtle populations. Conservation Biology 16:1647-1652. Steen, D.A., Aresco, M.J., Beilke, S.G., Compton, B.W., Condon, E.P., Dodd Jr., C.K., Forrester, H., Gibbons, J.W., Johnson, J.L., Langen, T.A., Oldham, M.J., Oxier, D.N., Saumure, R.A., Schueler, F.W., Sleeman, J.M., Smith, L.L., Tucker, J.K., Gibbs, J.P., 2006. Relative vulnerability of female turtles to road mortality. Conservation. 9, 269–273. Steen, D.A., Gibbs, J.P., 2004. Effects of roads on the structure of freshwater turtle populations. Conservation Biology 18, 1143–1148.

I would like to acknowledge Rachel Lewis, Scott Jones, and the other members of the MU Herp Lab for their help.

Funding was provided by The Marshall University Foundation and the John and Janett Casto Thesis Award. www.marshall.edu/herp/Grad_Students/Aaron_Gooley/Main.htm