Nutrient effects on soil fungal communities in a coastal plain wetland ecosystem

Abstract

Anthropogenic influences such as urbanization and intensive agriculture practices modify nutrient and water cycles in significant ways. These activities can cause disruptions to microbial mutualisms, especially in low-nutrient wetland ecosystems. Due to ongoing alterations to nutrient and moisture variations, the composition of fungal microbe communities may be shifting in unexpected ways. In this study, I investigated how long-term fertilization, and hydrologic alterations affect soil fungal microbial communities in a historically low-nutrient coastal plain wetland. I hypothesized that long-term fertilization and varying water conditions through ditching influenced patterns in fungal communities to different degrees. I tested this hypothesis at a long term nutrient addition (N-P-K fertilizers) and disturbance (mowing) experiment (established in 2003) located at East Carolina University's West Research Campus in Greenville, North Carolina. I specifically examined fungal microbe communities (based on amplicon sequencing of the internal transcribed spacer (ITS) region between the small and large subunits of the ribosomal RNA gene) in mowed plots undergoing and not undergoing nutrient enrichment. Results revealed that nutrient enrichment and ditch effects influenced fungal community composition, with community evenness being higher in wetter, unfertilized soils than drier fertilized soils over time. Additionally, soil treatments were more strongly associated with specific subsets of less abundant fungal families.