The Use of Carbon Isotopes (¹³C,¹⁴C) in Soil to Evaluate Vegetation Changes During the Holocene in Central Brazil

Abstract

This paper presents carbon isotope data measured in three soil profiles from the Salitre area, Central Brazil. The study forms part of a research project on tropical and subtropical soils in Brazil, in which the main objective is to use carbon isotopes to provide information about vegetation changes that have occurred in relation to climate changes during the Holocene. 14C data from charcoal samples and soil organic matter (SOM) indicate that the organic matter in the soils studied is of Holocene age at least. Furthermore, the presence of a significant amount of charcoal in the soils suggests that forest fire was a significant ocurrence during the Holocene and probably had an important role in determining the dynamics of forest vegetation in the study area. Correspondingly, 13C data indicate that C3 plants provided the dominant vegetation of the study area, even during the dry periods when savanna vegetation is supposed to have replaced the forest communities. This study contributes to our better understanding of the relation between climatic changes and vegetation in the subtropical region of Brazil.

Late Pleistocene and Holocene Vegetation, Climate Dynamics, and Amazonian Taxa in the Atlantic Forest, Linhares, SE Brazil

“…Carbon isotope composition ( 13 C) of the organic matter preserved in soils can be used to study past vegetation dynamics relating to the abundance of C 3 and C 4 plants (Pessenda et al 1996(Pessenda et al , 2004(Pessenda et al , 2009. C 4 plants (especially Poaceae and Cyperaceae) are more efficient in the use of water and usually more competent than C 3 plants in relatively warmer and dryer environments.…”

Os fragipãs e duripãs das depressões dos tabuleiros costeiros do nordeste brasileiro: uma proposta de evolução

“…Resultados do δ δ δ δ δ 13 C: Todos os δ 13 C foram inferiores a -25, o que indica uma vegetação em C 3 , provavelmente florestal (Button, 1991;Pessenda et al, 1996). Todavia, o hiato cronológico importante entre as trincheiras T30 e T7 (13.730 AP e 2.630 AP) não permitiu excluir a hipótese de variações de vegetação durante este período.…”

Dinâmica do ecótono floresta-campo no sul do estado do Amazonas no Holoceno, através de estudos isotópicos e fitossociológicos

“…Estudos em transecção floresta-campo da Amazônia realizados por Desjardins et al, (1996) indicaram avanços da floresta no Holoceno médio/ superior. Estudos desenvolvidos por Gouveia (1996), Pessenda et al, (1996bPessenda et al, ( , 1998aPessenda et al, ( , 2001) e Freitas et al, (2001) em uma transecção de 250 km entre as cidades de Porto Velho (RO) e Humaitá (AM), revelaram que durante o Holoceno inferior e médio/superior ocorreram vários períodos de mudanças de vegetação e provavelmente climáticas.…”