Date on Senior Honors Thesis

5-2016

Document Type

Senior Honors Thesis

Department

Biology

Degree Program

College of Arts and Sciences

Author's Keywords

cave salamander; cave zones; abiotic factors; salamander movement patterns; temperature relationship; relative humidity relationship

Abstract

The Cave Salamander, Eurycea lucifuga, is a common but poorly understood species of salamander that inhabits limestone features and karst systems across the eastern and midwest United States. As a species that can bridge the gap between subterranean and epigean environments, E. lucifuga may behave as a top predator and act as a significant facilitator in the flow of energy from the outside environment into the dark zone. The goal of this study was to document the seasonal movements of a local population of cave salamanders in Louisville, Kentucky, and the relationship between those movements and abiotic factors. Secondarily, I explored how the movements of individuals among the cave zones affect the food web of the cave as a whole. Weekly or biweekly surveys were undertaken in Sauerkraut Cave from March 2015 to February 2016. Each encountered salamander was photographed, and I recorded its distance from the entrance (m), height upon the cave wall (cm), side of the passage (left or right, when viewed from the entrance), and substrate upon which it occurred. I also measured temperature (°C) and relative humidity (%) at regular intervals throughout the cave. Salamander activity generally followed variation in temperature and humidity, with proportionally more individuals sighted in the twilight zone during the warmer months, followed by a shift to the dark zone during the colder winter months. The number of salamanders recorded per survey increased as the year progressed, with the most current numbers being more than double the average number of salamanders seen per survey for the entirety of 2015. Individuals that were recaptured more than twice exhibited more variable movement patterns than the general population, perhaps due to courtship and breeding behavior. Further study of the seasonal fluctuations of cave salamander behavior in local populations such as this could be crucial in understanding the complexities of cave ecosystems across the temperate United States.

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