Document Type



Doctor of Philosophy (PhD)



First Advisor's Name

Maureen A. Donnelly

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

Alessandro M. Catenazzi

Second Advisor's Committee Title

Committee Member

Third Advisor's Name

Kenneth J. Feeley

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Joel T. Heinen

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Steven F. Oberbauer

Fifth Advisor's Committee Title

Committee Member


metabolism, amphibian, tropics, climate change

Date of Defense



Metabolism is a fundamental biological process that determines the rate at which organisms process energy and materials, and determines the availability of resources for growth, maintenance and reproduction. Metabolic rates scale across levels of organization from cells to whole organisms and affect population, community, and ecosystem processes. Anthropogenic climate change and other environmental changes are predicted to have major impacts on the energetics of organisms that will be mediated through metabolic physiology. Tropical ectotherms, such as amphibians, may be among the most vulnerable to metabolic impacts of climate change as a result of being ectothermic, having high thermal sensitivity, and living at relatively high temperatures (close to upper thermal tolerances). However, many predictions use universal metabolic scaling relationships derived predominantly from temperate taxa in modeling efforts, and there has been little work to determine whether such relationships also characterize the metabolic rates of tropical ectotherms.

I use field-based respirometry to examine the metabolic physiology of tropical amphibians along an elevational gradient on the eastern slope of the Andes in southeastern Peru. I describe variation in metabolic physiology of tropical amphibians and how it relates to patterns of phylogeny, ecology, and environment. I demonstrate that there are consistent diel rhythms in resting metabolic rates that lead to significant differences between day and night, and that the timing of circadian rhythms differs among families. I confirm that there are strong phylogenetic signals in the patterns of resting and active metabolic rates of tropical amphibians and illustrate that accounting for phylogenetic differences is important for analyses of interspecific comparisons of metabolic physiology. I discuss how variation in metabolic physiology may relate to ecological characteristics, and how the combination of physiology and ecology may determine ecological strategies and vulnerability to metabolic impacts of climate change. Consideration of the variation in amphibian metabolism is essential to make accurate predictions of metabolic impacts of climate change, to inform conservation and management decisions, and to understand the integrative biology of tropical amphibians







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