Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Biology (PhD)

Degree Level



Biological Sciences


James M. Walker

Committee Member

McNabb, David

Second Committee Member

Willson, John David

Third Committee Member

Tipsmark, Christian


amphibians, ecosystems, ecology, population


The need to study and monitor amphibian populations is increasing along with the threats to their population stability and persistence in nature. Northwest Arkansas is one of the fastest growing areas in the nation and with that growth comes rapid changes in land use, massive alterations to habitats, habitat loss, and the introduction of nonnative plants and animals. Ambystoma annulatum (Ringed Salamander) is an Ambystomatid endemic to the Ozark and Ouachita Mountains of southern Missouri, northern and western Arkansas, and eastern Oklahoma giving it a relatively small distribution compared to most Ambystoma. Therefore, Arkansas constitutes a significant portion of the home range of A. annulatum. However, due to the secretive nature of A. annulatum little is known about its biology, ecology or population status in the state. Consequently, this has resulted in its designation as a species of special concern in the state of Arkansas. In this dissertation, I attempted to gather information on various aspects of A. annulatum biology and ecology in Northwest Arkansas. I first studied the demographics of an Ambystoma annulatum breeding population in an atypical environment in Washington County, Northwest Arkansas, USA. This was done to understand dynamics of a breeding population of A. annulatum in a highly disturbed habitat. Next I studied sexual dimorphism in body size, head dimensions (length, width, and depth), limb length, and tail length in A. annulatum. Understanding sexual dimorphism in animals helps to shed light on evolutionary drivers such as sexual selection, or variation in ecological requirements between males and females. Then I surveyed 155 natural and manmade ponds in Washington County for A. annulatum presence, along with other herpetofauna species, to get a snapshot of its occurrence. Finally, I isolated a Naegleria amoebae from the gut of an adult A. annulatum to add to the body of information on amphibian-parasite associations.