Date of Award:

8-2023

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Committee Chair(s)

Susannah French

Committee

Susannah French

Committee

Zachariah Gompert

Committee

Karen Kapheim

Committee

Al Savitzky

Committee

David Koons

Abstract

Wildlife populations across the globe are poised to lose their natural habitat to urbanization, yet there is limited information on how different species handle living in cities. Animals in urban environments are often susceptible to novel stressors, which can threaten their individual health and population viability. The physiological characteristics of animals, such as those related to metabolic hormones, oxidative stress, and immunity, are expected to be important for survival in this context. If so, animals persisting in urban areas may demonstrate physiological differences from their natural counterparts, perhaps due to evolutionary change. These potential outcomes have been documented in birds and mammals, but other taxonomic groups such as reptiles have been studied far less. For this dissertation, lizards were sampled in urban and natural areas for six years to (i) compare annual population survival, (ii) identify physiological traits important for survival, (iii) map the genetic basis of these traits, and (iv) test if and how the physiological traits are evolving in urban environments. Lizard survival was lower in urban environments and related to differences in immunity. Each physiological trait had a low to moderate heritable basis linked to few genetic loci with measurable effects. Population-level genetic comparisons revealed lizards in urban areas to be differentiated from those residing in natural areas, though shared genetic variation was present among populations along with comparable levels of genetic diversity. Differential selective pressures on the traits and their associated genetic loci were not detected, but indicators of genetic drift were evident across the landscape. Altogether, these findings shed light on the interconnectedness of population demography, physiology, and genetics for reptiles residing in urban environments.

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