Microbial communities in Cerrado soils under native vegetation subjected to prescribed fire and under pasture

Laura Tillmann Viana,Keith Kisselle,Roger A Burke,Mercedes Maria Da Cunha Bustamante,Richard Zepp,Alexandre De Siqueira Pinto,Marirosa Molina

doi:10.1590/s0100-204x2011001200012

Laura Tillmann Viana, Keith Kisselle + Show 5 more

Open Access

https://doi.org/10.1590/s0100-204x2011001200012

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Abstract

The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerrado stricto sensu" and "campo sujo"), under different fire regimes, and a 20-year-old active palisadegrass pasture in the Central Plateau of Brazil. Microbial biomass was higher in the native plots than in the pasture, and the highest monthly values were observed during the rainy season in the native plots. No significant differences were observed between fire regimes or between communities from the two native vegetation types. However, the principal component (PC) analysis separated the microbial communities by vegetation cover (native x pasture) and season (wet x dry), accounting for 45.8% (PC1 and PC3) and 25.6% (PC2 and PC3), respectively, of the total PLFA variability. Changes in land cover and seasonal rainfall in Cerrado ecosystems have significant effects on the total density of soil microorganisms and on the abundance of microbial groups, especially Gram-negative and Gram-positive bacteria.

Highlights

Savannas of Central Plateau of Brazil, locally known as Cerrado, comprise the second largest biome of South America with an area of approximately two million square kilometers
The Cerrado is characterized by high plant diversity and different vegetation types forming a density gradient of woody species
The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis

Summary

Introduction

Savannas of Central Plateau of Brazil, locally known as Cerrado, comprise the second largest biome of South America with an area of approximately two million square kilometers. The Cerrado is characterized by high plant diversity and different vegetation types forming a density gradient of woody species. The Cerrado is one of the 34 biodiversity hotspots in the world, i.e., areas with high biodiversity and accelerated loss of habitats (Mittermeier et al, 2005). Rapid conversion of native Cerrado areas to agriculture has been occurring since 1960 with the establishment of the Brazilian Federal District and the construction of Brasília. By 2002, approximately 39.5% of the Cerrado was already converted primarily into pastures (26.5%), and cropland (10.5%), (Sano et al, 2008).

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