Date of Award
Spring 5-10-2024
Degree Type
Thesis
Degree Name
Master of Science in Integrative Biology
Department
Department of Ecology, Evolution, and Organismal Biology
Committee Chair/First Advisor
Nicholas S. Green
Second Advisor
Todd Pierson
Third Advisor
Whitney Preisser
Abstract
Urbanization is an example of human induced rapid environmental change that can have wide-reaching ecological effects, including habitat destruction, fragmentation, and alteration of local climates. Effects of urbanization have been shown to impact wildlife, as disturbances resulting from urbanization can create novel environments and selective pressures that could lead to changes in morphology, physiology, or both. Small mammals such as rodents are an ecologically important set of wildlife species because they are a key prey item for several predators, hold strong influence over plants as a primary consumer, and some species carry and transmit major human and animal diseases. Previous studies have documented phenotypic effects in small mammals associated with urbanization such as an increase in body size associated with increased mean annual temperature. What is not clear from previous work are the mechanisms that drive these phenotypic changes to occur. I trapped small mammals at 23 sites along the urban rural gradient centered on Atlanta, Georgia from May-August 2023. I found that (1) small mammal size differed with urbanization status with white-footed mice (Peromyscus leucopus) being shortest in suburban areas, eastern chipmunks (Tamias striatus) being shortest in urban areas, and hispid cotton rat (Sigmodon hispidus) being largest at rural sites; (2) mass:length allometry varied with urbanization status in species-specific ways; (3) small mammal triglyceride levels differed with urbanization status with blood triglycerides being lowest in suburban areas; and (4) small mammal stress hormone levels did not differ with urbanization status. Future studies should consider species-specific traits and resource needs as well as alternative physiological endpoints that reliably integrate information about nutritional status over longer periods of time; or, a transplant or mesocosm experiment that directly compares physiological endpoints of urban and rural animals in simulated rural and urban environments.