The Role of Conservation Physiology and Environmental Change in Amphibian Declines
Goff, Cory B.
Environmental change associated with anthropogenic alterations to habitat and the synergistic effects with climate change and disease can render habitats unsuitable and affect the physiological health of species. This can ultimately affect survival and fitness. Amphibians are one group of vertebrates especially vulnerable to changes in environmental quality. Using multiple measures of physiological health can aid in identifying populations at increased risk of declines. This dissertation focuses on research that examines the effects of environmental variables on the health of larval amphibians through field sampling, laboratory experiments, and outdoor mesocosms. The first chapter is an introduction to the main topics addressed in my research. The second chapter includes the results of field sampling to measure environmental variables at multiple spatial scales and their effects on three physiological health metrics of ornate chorus frog (<i>Pseudacris ornata</i>) tadpoles to identify potential correlates of population declines. The third chapter examines the effects of increased water temperatures on multiple physiological health metrics in a larval anuran, the Rio Grande leopard frog (<i>Rana berlandieri</i>) by manipulating water temperatures via tank heaters in the lab and from a lack of shade cover in outdoor mesocosms. Together, my research shows that lower environmental quality, such as increased water temperatures from climate change or habitat alteration, may result in chronic stress in larval amphibians, reducing physiological health and leading to declines. However, depending on the species and aquatic environment, some individuals may benefit from warmer water temperatures. My research suggests multiple health metrics are needed to understand the complex effects of environmental change on larval amphibian health and provides suggestions for the management of these species.
Bacterial communities, Environmental stress, Water-borne hormones, Corticosterone
Goff, C. B. (2019). <i>The role of conservation physiology and environmental change in amphibian declines</i> (Unpublished dissertation). Texas State University, San Marcos, Texas.