Evaluating the effects of urbanization on meiofauna biodiversity in Chattanooga’s lentic ecosystems through GIS applications

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.