Date of Award

2016

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Jayme Waldron

Second Advisor

Anne Axel

Third Advisor

Thomas K. Pauley

Fourth Advisor

Shane Welch

Abstract

Monitoring programs often suffer from imperfect detection resulting in skewed population estimates, biased estimates of changes in occupancy over time, and can result in an underestimated proportion of area occupied (PAO) by a species. To increase the detection probability, researchers must increase sampling both spatially and temporally. Callback surveys are an active form of sampling that have been used to monitor many avian and mammal species. During callback surveys, the call of a conspecific male is projected with the intention of increasing probability of detection by eliciting a response from territorial males. These methods work for organisms that establish breeding territories and defend them both physically and vocally. Callback recordings have been used to incite responses in anurans since the 1960s; however, callback surveys have received little attention in anuran, i.e., frog monitoring programs, despite their potential utility for increasing detection probabilities. Because the successful use of animal callback surveys has largely centered on territorial species (eg., Botaurus lentiginosus and Rallus limicola), and anuran calling behavior is not always associated with territoriality, I examined the role of territorial behavior in the efficacy of anuran callback surveys using two congeners (Rana catesbeianus and Rana grylio). In this study, active sampling significantly increased the probability of detection for both species. Rana catesbeianus and R. grylio were 26 and 7.5 times more likely to be detected during active sampling, respectively. My results indicate that callback surveys may provide a more effective method for surveying anurans, optimizing the probability of detection, while decreasing spatial and temporal sampling.

Subject(s)

Anura -- Behavior.

Anura -- Research.

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