Document Type

Student Research Paper

Date

Spring 2018

Academic Department

Biology

Faculty Advisor(s)

Dr. David Bowne

Abstract

The painted turtle (Chrysemys picta) has temperature-dependent sex determination, meaning that the temperature of the nest determines sex. Vegetation cover of nests has been found to affect the hatchling sex ratio, indicating that there is an indirect causal relationship between sex ratio and vegetation cover. This study looked at the relationship between thermal nest environment and environmental variables (nest temperature and soil composition). Simulated turtle nests were created around a lake located on Elizabethtown College’s campus in Elizabethtown, Pennsylvania in locations with varying amounts of cover. A temperature data logger was placed in each nest to record the potential incubation temperature from the end of May to mid-July of 2017. Densiometer readings were taken to determine percent cover at each location. Soil composition was also determined for each nest site by using the soil hydrometer method. It was found that as amount of cover increased, average nest temperature decreased significantly. There was no significant relationship between soil composition and nest temperature. These results could help in assessing the impacts of land use changes around turtle ponds.

Notes

Senior thesis.

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