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Thesis Abstract – Gormally (2015)

Title:

Comparing Corticosterone Concentrations in Male Sceloporus occidentalis from Urban and Protected Habitats

Author and college:

Brenna Gormally, Pomona College

Date:

May 2015

Degree:

Bachelor of Arts in Biology

Advisor:

Kristine Kaiser, Department of Biology, Pomona College

Abstract:

Urbanization is a pervasive phenomenon and has been shown to have a variety of effects on animals. Previous studies have shown that urbanization affects hypothalamic-pituitary-adrenal axis functioning as well as glucocorticoid circulation in a range of species. The aim of this study was to compare basal and stress corticosterone (CORT) concentrations in urban, protected, and intermediate habitat types in male Western fence lizards (Sceloporus occidentalis) throughout the Los Angeles Basin. Quantifying plasma glucocorticoid levels has often been used as an indicator of physiological stress and therefore CORT is a compelling hormone to measure. Competitive binding enzyme immunoassays were used to quantify both basal and stress CORT concentrations (n=51). Stress CORT levels were significantly higher relative to basal levels, however there was no difference in either sample type between habitat type. Samples from the intermediate habitat of the Pomona College Organic Farm trended towards higher basal CORT levels relative to those from both protected and urban grouped sites. These results suggest that small, intermediate-urban habitat patches create unique stressors and challenges that Western fence lizards respond to differently relative to their urban and protected counterparts.

For more information:

Contact Wallace Meyer – Wallace.Meyer@Pomona.edu