Project Director

Leasi, Francesca

Department Examiner

Tucker, John; Hunt, Nyssa

Department

Dept. of Biological and Environmental Sciences

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

Urbanization is a leading driver of biodiversity loss in freshwater ecosystems, yet its effects on meiofauna—microscopic invertebrates that serve as key bioindicators of ecosystem health—remain poorly understood in lentic environments. This study evaluated the effects of urbanization on meiofaunal biodiversity in ten lentic waterbodies across Hamilton County, Chattanooga, Tennessee, by integrating environmental DNA (eDNA) metabarcoding, in-situ abiotic measurements, and Geographic Information Systems (GIS)-based land use analysis. Water samples were collected between January and April 2023 and processed using 18S rRNA amplicon sequencing to assess biodiversity as richness (amplicon sequence variants or ASVs, phylogenetic diversity or PD, and community composition). Land use and land cover (LULC) data within 0.1 km buffer zones were extracted using high-resolution National Agriculture Imagery Program (NAIP) aerial imagery in ArcGIS Pro. A total of 221 ASVs were identified across the ten sites. ASV richness and phylogenetic diversity were significantly higher at moderately urbanized sites compared to low-urbanization sites, suggesting a non-linear relationship between urbanization and biodiversity potentially consistent with the intermediate disturbanc hypothesis. Meiofaunal richness, phylogenetic diversity, and community composition all differed significantly among urbanization categories, with turbidity emerging as a significant abiotic predictor of richness and PD, and temperature identified as a significant predictor of community composition. These findings demonstrate that freshwater meiofauna respond sensitively to urban-driven environmental gradients and can function as effective bioindicators of ecosystem change. This project represents one of the first studies to integrate GIS-based spatial analysis with eDNA metabarcoding to assess freshwater meiofaunal biodiversity, providing a methodological framework for future urban biomonitoring research.

Acknowledgments

I would like to express my sincere gratitude to my thesis advisor, Dr. Francesca Leasi, for her guidance, support, and mentorship throughout this project. Her expertise and encouragement were invaluable to the completion of this research. I am also grateful to my committee members, Dr. John Tucker and Nyssa Hunt, for their time, feedback, and thoughtful insights that strengthened this work. I would like to thank the Department of Biology, Geology, and Environmental Science at the University of Tennessee at Chattanooga for their continued support of my research endeavors. Finally, I would like to thank my peers, friends, and family for their continued encouragement and support throughout my undergraduate career.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

5-2026

Subject

Meiofauna; Freshwater ecology--Environmental aspects; Urbanization--Environmental aspects

Keyword

Meiofauna; Freshwater; GIS; Metabarcoding; Urbanization

Discipline

Environmental Indicators and Impact Assessment

Document Type

Theses

Extent

iii, 55 leaves

DCMI Type

Text

Language

English

Rights

http://rightsstatements.org/vocab/InC/1.0/

License

http://creativecommons.org/licenses/by/4.0/

Additional Files
Table Supplemental 1.xlsx (56 kB)
StoryMapPresentation.pdf (8857 kB)
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