Fungal community structure and functional genes abundance in Brazilian drylands under desertification process

• Autor(a) principal: Silva, Danilo Ferreira da
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/11/11140/tde-03102023-151944/
• topic: Bioma Caatinga; Caatinga biome; Ciclagem de N e P; Comunidades microbianas; Ecological processes; Environmental sustainability; Microbial communities; N and P cycling; Processos ecológicos; Sustentabilidade ambiental

Desertification in drylands causes the depletion of the soil\'s natural resources. Degradation alters all ecological processes that occur naturally in soil. This degradation is largely due to changes in the microbial communities present in this complex soil-plant- atmosphere ecosystem. One of the main communities responsible for maintaining the biological balance of the soil is the fungal communities, which participate in numerous processes, such as nutrient cycling, decomposition of organic matter, solubilization processes by organic acids, transport of nutrients and water. However, studies that report the consequences of the desertification process on soil fungal communities and access to specific ecological functions are scarce, especially in the Caatinga biome in Brazil, one of the most populous semi-arid region in the world. The study was conducted in the desertification area of Irauçuba, state of Ceará, Brazil, where nine restoration areas were established to prevent overgrazing by animals in 2002. The aim of this study was to describe the modulation of the soil fungal communities as well as the abundance of functional genes related to nitrogen and phosphorus cycles in a desertification gradient. Two chapters were considered, the first showing that overgrazing alters fungal community structure and that grazing exclusion is effective in restoring this community. Whilst the second shed light on the functional genes, showing that the desertification process reduces the abundance of genes related to N and P cycles while grazing exclusion could recover. Therefore, we took an important step towards a theoretical foundation that seeks an efficient strategy in combating the desertification of drylands.