Date of Award

5-2024

Degree Type

Honors College Thesis

Academic Program

Biological Sciences BS

Department

Biological Sciences

First Advisor

Micheal Davis, Ph.D.

Second Advisor

Kevin Kuehn, Ph.D.

Advisor Department

Biological Sciences

Abstract

One of the most diverse ecosystems, longleaf pine (Pinus palustris) habitats comprise only a small fraction of the habitat they once spanned in the Gulf Coastal Plain Region of the Southeastern United States. To preserve longleaf pine ecosystems, proper prescribed burning techniques and ecosystem management are essential for preventing high intensity wildfires and increasing species diversity. Little is known about the effects of prescribed fires on carbon levels, nitrogen levels, and microbial biomass in longleaf pine forests. These components are crucial for determining how well burned areas are recovering at a microbial level compared to unburned areas. The greater the microbial abundance and diversity that returns to soils after a burn can indicate greater relative recovery rates, making them important to analyze over time. Previous studies have described varied results on the effects of prescribed fires on carbon and nitrogen levels, but their effects on microbial biomass in longleaf pine forests is understudied, presenting a knowledge gap in this area of study. We studied the effects of prescribed fire on levels of soil carbon, nitrogen, and fungal biomass (as ergosterol) prior to a prescribed burn and 2, 3, and 4 months post burn. Samples were collected from 12 burned sites and 12 unburned control sites inside and outside of cattle plots, encompassing 188 total samples. It was hypothesized that carbon and nitrogen levels would increase three weeks after the prescribed burn in burned plots and decrease in the following two- and four-month sample collections. Soil fungal biomass (ergosterol) levels were expected to increase directly after the burn and decrease in the following two- and four-month samples in burned plots. Unburned control plots were expected to have similar levels, dipping three weeks post fire. Effects of the fire were assessed using a two-factor ANOVA. The results demonstrate that carbon levels (which were lower in burned plots prior to the burn) spiked directly after the burn and continually decreased after two months. Nitrogen levels decreased overall, and fungal biomass levels initially spiked, decreased, and then increased again after four months post burn. These results help bridge the knowledge gap on how prescribed burns affect fungal biomass levels and contribute more data to the varied results of research on carbon and nitrogen levels following prescribed burns. Management plans should consider these effects when planning intervals between prescribed fires, as well as what kinds of fires would better benefit longleaf pine ecosystem conservation and restoration.

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