Date of Award
5-10-2026
Date Published
June 2026
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Biology
Advisor(s)
Christopher Fernandez
Keywords
Fungal Ecology;Microbial Ecology;Nutrient Cycling
Abstract
Anthropogenic nitrogen (N) deposition is known to alter nutrient limitation in temperate forests, yet belowground microbial responses under shifting phosphorus (P) and N+P availability remain unclear. Using a long-term N × P fertilization experiment (MELNHE), we quantified fungal and bacterial community responses across organic and mineral soil. Nutrient additions restructured community composition without changing alpha diversity, indicating taxonomic turnover rather than richness loss. Nitrogen reduced ectomycorrhizal (EM) dominance and increased the relative abundance of saprotrophic fungi in the organic soil layer, including declines in nitrophobic taxa such as Cortinarius. Phosphorus structured fungal guild ratio non-linearly, with EM fungal dominance maximized at intermediate P availability. Phosphorus addition increased the relative abundance of melanized EM fungal taxa such as Cenococcum geophilum. Fungal guilds partitioned nutrient niches, with saprotrophs responding to N, EM fungi to P, and arbuscular mycorrhizal fungi to combined N and P. Bacterial communities exhibited N-driven shifts from oligotrophic to copiotrophic taxa. Together, these results demonstrate that N and P regulate soil microbial communities through distinct, depth-dependent and trait-mediated pathways, driving functional reorganization with consequences for carbon cycling in temperate forest soils.
Access
Open Access
Recommended Citation
Plecki, Caroline Frances, "Nitrogen and phosphorus fertilization shifts fungal and bacterial community composition and functional groups in temperate forest soils" (2026). Theses - ALL. 1039.
https://surface.syr.edu/thesis/1039
