Date of Award

8-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Lisa Hazard

Committee Member

Paul Bologna

Committee Member

Alexis Khursigara

Committee Member

Kirsten Monsen-Collar

Abstract

One of the most robust amphibians is the American Bullfrog, Lithobates catesbeianus, which is a widespread species that is invasive worldwide, and is broadly tolerant of a range of environmental conditions. Despite this tolerance, survival and performance of adult L. catesbeianus can be negatively affected by increasing temperatures and salinity resulting from anthropogenic impacts, such as climate change and road salts. This study focuses on the effects of acute salinity exposure (mimicking road salt influx into a pond) on L. catesbeianus tadpoles at different larval stages. Increased salinity was predicted to negatively affect two physiological performance measures. Critical maximum temperature (CTₘₐₓ , measured as loss of righting response) and stamina (measured as time to exhaustion while swimming against a current) were measured at varying salinities for tadpoles classified as premetamorphic (growth phase) or prometamorphic (hind limb development) stages. Mass change (% of initial mass) was also measured for both experiments. CTₘₐₓ was mass-dependent for premetamorphic tadpoles, but not prometamorphic tadpoles; there was no effect of salinity on CTₘₐₓ for either stage. Tadpoles exposed to higher salinity had lower stamina and greater percent mass loss than those at lower salinity levels. Despite not finding an effect of salinity on critical temperature, the study does support an effect of salinity on the physiological performance of L. catesbeianus tadpoles. Further research is needed to better understand how longer exposure to anthropogenic pollutants affects these crucial bioindicators and their ecosystems.

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