Graduation Date

Spring 2017

Document Type

Dissertation/Thesis

Program

Master of Science degree with a major in Biology

Committee Chair Name

Dr. John Reiss

Committee Chair Email

John.Reiss@humboldt.edu

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Dr. Stephen Sillett

Second Committee Member Email

prof.sillett@gmail.com

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Dr. Michael Mesler

Third Committee Member Email

Michael.Mesler@humboldt.edu

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Dr. Sharyn Marks

Fourth Committee Member Email

Sharyn.Marks@humboldt.edu

Fourth Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Biology

Abstract

The habitat use and movements of small, secretive salamanders are generally poorly understood, in part due to the difficulty associated with marking and recapturing such animals. This study was designed to test the efficacy, both in the laboratory and in the field, of using passive integrated transponder (PIT) tags to mark and track two small-bodied plethodontid salamander species native to coastal northwestern California, Aneides vagrans, the Wandering Salamander, and Ensatina eschscholtzii, the Ensatina Salamander.

Aneides vagrans inhabits tree crowns. Using cover objects and visual encounter surveys, I searched for A. vagrans in the angiosperm understory canopy at least twice monthly from February 2015 through June 2016. All fieldwork was conducted at the Redwood Experimental Forest, a US Forest Service property in Klamath, California. I found no evidence that A. vagrans is present in this habitat, and thus I could not PIT tag or track the movements of this species.

In the laboratory experiment, I compared the survival, change of mass, and general behavior of PIT tagged E. eschscholtzii to a control group. There was no significant difference between groups in initial mass or SVL. Incision points for all tagged salamanders had healed to the point of scarring after four days and no signs of infection were seen. Upon conclusion of the 90 day experiment, I observed 100% survival and tag retention. Implantation of a PIT tag had no significant effect on percent change in mass or general behavior.

To test the efficacy of remote detection of fossorial salamanders and track their movements, I used visual encounter surveys and artificial cover objects to capture and tag over 50 free-ranging E. eschscholtzii from October 2015 to March 2016. Using a PIT tag reader connected to a portable antenna, I detected tagged E. eschscholtzii from July 2016 to January 2017. I mapped location data from the remote detection surveys and used it to calculate movement distances for each animal. I found no significant difference in the average distance moved between males and females. Furthermore, I found a significant increase in average recapture rate using remote detection compared to visual encounter surveys using artificial cover objects. This shows the promising advantages of using PIT tags to mark small plethodontids, including the ability to remotely detect small, secretive individuals and a corresponding increase in recapture rates.

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