Master of Science, The Ohio State University, 2022, Environment and Natural Resources

Artificial light at night (ALAN) is a growing environmental stressor due to human expansion and increased urbanization. ALAN has shown to have significant impacts on a suite of taxa and on multiple levels of biological organization, but most research has focused on individual to population levels of biological organization. Furthermore, there has been a disproportionate research emphasis on terrestrial vs. aquatic ecosystems. In this study, I investigated the impacts of ALAN on riparian mammal space use and food webs along 12 small streams in Columbus, Ohio, USA. Seasonality and time of day were the strongest drivers of mammal community composition along streams, despite the presence of ALAN. Seasonality, sediment size, and other site-level differences, but not ALAN, were associated with total mammal space use and species richness. No species-specific small mammal captures or species/guild-specific camera-trap encounters were impacted by ALAN. In the context of this study, sediment size is likely a proxy for either stream size or urbanization but also a potentially important structural factor related to small-mammal movement across streams. ALAN presence was related to the proportion of energy derived from aquatic vs. terrestrial primary producer pathways in the genus Peromyscus, the only small mammals with sufficient sample size to estimate diet proportions. At illuminated reaches, Peromyscus nutritional subsidies derived from aquatic primary producer pathways (i.e., originating from stream periphyton) were 1.2% lower at lit compared to unlit reaches. Canopy cover was also associated with the proportion of energy derived from the terrestrial primary producer pathway that is indirectly consumed by Peromyscus (i.e., originating from aquatic detritus). Site – as a random effect in linear-mixed models – explained the greatest amount of variation in the proportion of energy derived from different primary producer pathways. Overall, I did not find e (open full item for complete abstract)

Committee: Mažeika Sullivan (Advisor); Robert Gates (Committee Member); Stanley Gehrt (Committee Member) Subjects: Ecology; Environmental Science; Natural Resource Management; Wildlife Conservation; Wildlife Management