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Texas A&M University (2021)

The Response of Soil Microbial Communities to the Interactive Effects of Drought and Fire in a Semi-Arid Savanna

Peterson, Matthew James

Titre : The Response of Soil Microbial Communities to the Interactive Effects of Drought and Fire in a Semi-Arid Savanna

Auteur : Peterson, Matthew James

Université de soutenance : Texas A&M University

Grade : Master of Science (MS) 2021

Résumé
The frequency and severity of both drought events and unintentional wildfires are expected to increase within the next century. In addition to having profound effects on vegetation structure and composition, this is expected to disrupt key nutrient cycling processes within the soil. Soil microbes play a fundamental role in degrading soil organic matter as well as transporting nutrients to plants. Changes in microbial biomass or composition induced by fire and drought may decrease nutrient cycling efficiency. Despite numerous studies assessing the individual impacts of drought and fire on soils, few studies have analyzed their combined effects. Our objective was to assess the impacts of drought, fire, and their combined impacts on the soil microbial community, the abundance of the microbes that compose the microbial community, and extracellular enzyme activity. At the Texas A&M AgriLife research station in Sonora, Texas, a full-factorial randomized plot experiment was established to assess the effects of drought and fire on soil microbial community composition and activity in a semi-arid savanna. Our results show that a semi-arid savanna experiences no negative impacts on the measured biological properties in response to drought, fire, or a combination of drought and fire. We also observed the presence of bacteria and fungi that are associated with drought tolerance, which may explain why there was no observed response to disturbance treatments in this study. We can conclude that fire remains a viable management option for the maintenance of herbaceous vegetation in a semi-arid savanna without concerns of negatively impacting soil biological properties even in the event of a short-term, extreme drought.

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Page publiée le 27 mai 2021