Effects of woody encroachment and prescribed fire on a small mammal community from a Cerrado fragment: subsidies for the improvement of an integrated management

• Autor(a) principal: Furtado, Luciana de Oliveira
• Data de Publicação: 2022
• 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/91/91131/tde-16092022-114809/
• topic: Conservação; Conservation; Didelphimorphia; Didelphimorphia; Fire suppression; Habitat use; Microhabitat; Microhabitat; Rodentia; Rodentia; Savana; Savanna; Supressão do fogo; Uso do habitat

The woody encroachment is a phenomenon that has been responsible for open habitat shifts in savannas around the world, through the increase in woody density. Unlike fire-sensitive ecosystems, savannas evolved with natural burns that act shaping open habitats richness in these fire-prone ecosystems where species are adapted to the local fire regime. Changes in these fire regimes can lead to negative outcomes in the local biodiversity. As a result of years of fire suppression, almost one-third of the largest South American savanna, the Cerrado, has been suffering from woody encroachment. The main consequences of fire suppression and woody encroachment are the increase in wildfires and the loss of open-area specialist biodiversity. The fire management is considered an important conservation tool for open habitats maintenance, controlling the woody encroachment and promoting the local biodiversity. The non-flying small mammals are good environmental indicators, due to their high habitat specificity and low dispersion capacity. Until the moment, no study addressing the woody encroachment impacts in Cerrado small mammal fauna was published, and regarding fire management influence, researches are concentrated in the Cerrado core region. Here, we evaluated for the first time - along two chapters - the impacts of woody encroachment and a prescribed fire event in a small mammal community in the southeast of Brazilian Cerrado. In the first chapter we compared data from 2003 and 2018, in order to assess the effects of 15 years of woody encroachment in the taxonomic diversity (richness, abundance and composition) of small mammals. We also evaluated the habitat use by the small mammal community considering two distinct scales (macro and microhabitat). Our results showed that small mammals are structured regarding habitat use across both scales. Although not affecting species richness, the woody encroachment is changing the local small mammal fauna, favoring forest-dwellers at the cost of open-area specialists. In the second chapter, we assess the impacts of a prescribed fire event in Cerrado grassland formations based on two experiments: 1. Temporal (before and after the fire in a \'campo sujo\' patch), and 2. Spatial (unburned and burned \'campo cerrado\' patches). The fire affected the small mammal community in different ways in the two experiments. In the Temporal experiment, open-area specialist rodents that were also vulnerable to woody encroachment were favored by the fire, while the richness and abundance of marsupials were negatively impacted. On the other hand, in the Spatial experiment, there were no major changes in the diversity parameters due to fire. The fire management seems to be an efficient strategy for woody encroachment impact control in the small mammal community. The maintenance of a mosaic composed of burned and unburned habitats can be essential to the conservation of open-area specialist species in savanna environments.