A Study of the Red-Bellied Turtle ( Pseudemys rubriventris ) Population in

1. A Study of the Red-Bellied Turtle (Pseudemysrubriventris) Population in Lake Marburg Located in CodorusPark,Hanover (PA) Lisa Haneschlager, Department of Biology, York College of Pennsylvania METHODS RESULTS Basking traps were set at each cove close to the location of the basking platforms that were introduced by the DCNR. Number of Turtles Caught per Trap per Day at Each Location in 2010 INTRODUCTION • A population of red bellied turtles (Pseudemysrubriventris), • is found in Lake Marburg, which is located in Codorus Park, • in Hanover Pennsylvania. Red-bellied turtles are on the • Pennsylvania threatened species list due to habitat degradation, • competition from invasive species, pollution, and disease • (Swarth, C. 1999). There are other species of aquatic turtles • located in Lake Marburg, including red-eared sliders, • (Trachemysscriptaelegans), yellow-bellied sliders, • (Trachemysscrptascripta), and painted turtles, (Chrysemys • picta). Both types of sliders are invasive and could potentially • compete with the red-bellied turtles, further impacting their • status within the lake (Stone, J.E. 2010). Understanding the • populations of each species of turtles is crucial for developing • conservation strategies. • Lake Marburg is a large manmade freshwater lake that consists • of several coves. It is unclear which coves within the lake the • turtles utilize for mating, finding food, and building nests. • Factors that may impact choice, include, • Food availability: Red-bellied turtles are • herbivorous as adults and thus require submerged • aquatic vegetation. • Access to appropriate nesting locations: • Red-bellied turtles are known to nest in open areas • adjacent to the water, including fields, meadows, • lawns and small forest openings (Swarth, C. 1999). • In 2007 the Department of Conservation of Natural • Resources (DCNR) built a protected beach in Dubs • Cove for the turtles to use as a secure nesting site. • This location was chosen because it is restricted to • the public. However, in previous years there was • very little nesting behavior observed at this site. • Temperature: Turtles do not need to bask when the • air temperature is high (Swarth, C. 1999) and in • fact will estivate under conditions of prolonged heat. • Temperature within the coves is impacted by the • depth of the water and may vary between years. • Boating activity: Several coves are used more • heavily during the summer months by boaters and • fishers and excessive activity may impact the turtle • behaviors. • The objectives of this study are to: Table 1: Months and locations where red-bellied turtles were captured and observed mating. The traps were checked once a day for no longer than two weeks at a time. The traps were reintroduced monthly from May through September. Table 2: Population estimate of red bellied turtles in Lake Marburg 2010. The Schnabel method was used to calculate this estimate. This estimate is based off of four isolated areas in the lake and may be an underestimation. Figure 3: Relationship between the amount of turtles captured in 2009 and 2010 The results of a two-way Anova demonstrated a statistically higher amount of turtles captured in 2009 than in 2010. (P=.0293) The turtles that were captured in the traps were measured for carapace length, width, and height, and they were weighed. Difference in Temperature (C) Between 2009 And 2010 Number of Turtles Caught per Trap per Day at Each Location in 2010 The turtles were marked using a carapace notching system that allows for the identification of a recaptured turtle. Population estimates were made using Schnabel Method.(Schnabel, Z.E. 1938) Figure 4: Difference in temperature during the days of research between 2009 and 2010. A two way Anova indicated higher temperatures in 2010 . P=.0001) CONCLUSIONS Figure 1: Number of turtles caught per trap in 2010 at each location May through September. A two-way Anova was performed to test the difference between Dubs and Chapel Cove for the year, The test indicated significantly more turtles at Chapel Cove. (P= .0005. ) • Turtles were more frequently captured in • Chapel Cove. This is the only location where • the red-bellied turtles were captured in 2010. Future • research could focus on this as a probable location • for nesting activity. • Red-bellied turtle mating behaviors were observed • in Chapel Cove and Marburg Flats primarily in May. • These locations differ in water depth and vegetation, • however both locations have low boating activity. • More turtles were captured in 2009 when the • temperature was lower. Temperature contributes to • the turtles behaviors and should be considered when • analyzing the population estimates and for future • studies. Difference in Species of Turtles Captured in 2010 OBJECTIVES • Observe locations of red-bellied turtles within Lake Marburg • during mating season, nesting season, and throughout the • active summer season • Begin to understand the distribution of the other species of turtles • found in Lake Marburg. • Estimate the population size of red bellied turtles in Lake • Marburg • Literature Cited: • Swarth, Christopher, W. 1999. Natural History and Reproductive Biology of the Red Bellied Turtle Conservation and Ecology of Turtles of the Mid- Atlantic Region. 30: 73-83. • Stone, E. 2010. Distribution and abundance of non-native red-eared slider turtles (Trachemysscriptaelegans) and native red-bellied turtles (Pseudemysrubriventris). • Schnabel, Z.E. 1938. The estimation of the Total Fish Population of a Lake. American Mathematic Monthly. 45: 348-352. Figure 2: Four species of turtles captured per day between May and September of 2010. A two-way Anova was performed to test the difference between painted turtles and red-eared sliders for the year. The test indicated the painted turtle were the most frequently captured species. (P=.0001). Acknowledgments: Dr J. Nolan, Dr K. Kleiner, Rick Harabin The Biology Department of York College, Department of Conservation Of Natural Resources and Codorus Park for allowing the research.