Date of Award

1-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Dirk Vanderklein

Committee Member

Lisa Hazard

Committee Member

Brad Oberle

Abstract

Urban forest fragments provide essential ecosystem services, yet their ability to sustain core soil functions under increasing anthropogenic disturbance associated with urbanization remains uncertain. Decomposition is a keystone process that links vegetation, microclimate, and microbial communities, and may be sensitive to biodiversity loss and structural simplification. Our study examined how biodiversity, canopy structure, and microbial communities affect decomposition across three urban forest patches in New Jersey and New York that represent a gradient of urbanization intensity. Using the Tea Bag decomposition, vegetation surveys, canopy measurements, microbial metabarcoding, and GIS-based road-density analysis, we evaluated whether decomposition remains stable despite structural and biological changes. Vegetation structure and diversity differed across sites, with higher road density (a proxy for surrounding urbanization intensity) associated with reduced mean DBH and increased compositional dominance at the most disturbed site. Fungal and bacterial assemblages also shifted, showing clear site-level separation and reduced phylogenetic diversity under high urbanization. However, decomposition rates remained relatively stable. Standardized tea assays showed that substrate quality rather than biodiversity was the strongest driver of mass loss, though understory composition collectively helped explain additional variation. Overall, results show that urbanization – driven environmental filtering alter vegetation and microbial communities, while decomposition can persist due to structural and compositional mechanisms. These findings depict the importance of maintaining diverse understories and structurally complex canopies to support soil processes in urban forests.

File Format

PDF

Available for download on Friday, February 19, 2027

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