Date of Award

8-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Member

Tzuen-Rong Tzeng, Committee Chair

Committee Member

Barbara Campbell

Committee Member

Alex Chow

Abstract

Fire is known to be capable of disturbing the composition of soil microbial communities due to changes in soil chemistry post-fire. These fire based disturbances leave behind higher levels of inorganic nutrients and toxic byproducts from incomplete combustion. Ecosystems are seen to recover from these disturbances given enough time. To determine if the controlled burns utilized on Cat Island in Georgetown South Carolina caused a disturbance, and if so to track the recovery from that disturbance, samples were collected from Cat Island over the course of 12 months from 03/07/2016 – 03/06/2017 from four separate locations. The pre-fire, post-fire and first four weeks of sampling were collected with a half-inch corer. The remaining monthly samples were collected with a 2 cm slidehammer. Each of the monthly timepoints were collected in quadruplicate. Samples of the soil immediately prior to the controlled burn were collected and compared to those acquired immediately after those locations had cooled enough for sample collection purposes. The purpose of the controlled burns on Cat Island is for the promotion of longleaf pine (Pinus palustris) growth in order to provide greater habitat for the Red Cockaded Woodpecker (Leuconotopicus borealis). To determine if there was an effect on the microbial communities from these controlled burns, DNA was extracted from each soil sample and used to measure the communities composition via 16S rRNA gene sequencing. The soil chemistry was also measured to compare to changes in the soil microbial communities. The specific measurements of soil chemistry included pH, soil moisture content, nitrate, ammonium, phosphorus, carbon and nitrogen. Examination of the changes in alpha diversity, beta diversity, and phylum level taxonomy of the microbial communities indicate that the severity of the fires that are utilized on Cat Island did not cause a large enough disturbance to the forest soil to create significant shifts in the microbial communities structure. The measurements of soil chemistry proved inconclusive as they did not appear to vary based on location of sampling, time of sampling, burn frequency of sampling location or time past burn. While the lack of change in relative abundance limits the inferences that can be made into the natural process of post-fire remediation that has evolved over time in forest ecosystems for recovering from fire-based disturbances, it does show that the management practices employed on Cat Island are not causing disturbances in the soil biology or chemistry that might prove detrimental to the ecosystems health. This positive result on the microbiological level means that this management practice can continue to be used without creating undesired changes in the forest habitat.

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