This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Pessenda, L. C.R. Articles by Gouveia, S. E.M. Search for Related Content GeoRef GeoRef Citation Social Bookmarking                         What's this?

The carbon isotope record in soils along a forest-cerrado ecosystem transect: implications for vegetation changes in the Rondonia state, southwestern Brazilian Amazon region

Laboratorio de 14C – CENA, USP, 13400 – 970, Piracicaba, SP, Brazil

B. M. Gomes

Universidade de Rondonia, Campus de Ji-Parana e Porto Velho, Rondonia, Brazil

R. Aravena

Quaternary Research Institute and Waterloo Centre for Groundwater Research, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1

A. S. Ribeiro

Universidade de Sergipe, Aracaju, 491000-000, Sergipe, Brazil

R. Boulet

S. E.M. Gouveia

ORSTOM, Instituto de Geosciencias, 05508-900, USP/NUPEGEL, Brazil

This paper presents carbon isotope data on soil organic matter (SOM) collected along an ecosystem transect that includes a wooded savannah (cerrado), a tropical semideciduous forest (cerradão), a forest tran sition type and a tropical forest. The study area is located in the Rondonia state, southwestern Brazilian Amazon region. ¹⁴C data of total soil organic matter and charcoal indicate that the organic matter in these soils is at least Holocene in age. The forest and forest transition sites are characterized by ¹³C soil depth profiles gener ated typically by C₃ plants, indicating no major changes in plant communities have occurred in this region during the time period represented by the isotope data. In contrast, the cerrado and cerradão have experienced significant vegetation changes during the Holocene. The d¹³C data (-30 to -27) obtained in the deepest part of the profile at the cerradão site show the expansion of the C₃ forest vegetation into this region during early Holocene. A vegetation change consisting of increased C₄ plant influence is reflected in the ¹³C-enriched ¹³C record shows a clear expansion of C₃ vegetation, particularly at the cerradão site. The regression/expansion of the forest and savannah vegetation documented at the cerradão and cerrado sites is probably related to changes from a humid to a drier climate and a return to more humid conditions and is in agreement with palaeoclimatic information reported for Brazil and the Bolivian Altiplano. This study suggests that large areas in the Amazon basin have been affected by vegetation changes during the Holocene and that soil organic matter in the transition areas between savannah and forest ecotones contains a valuable palaeorecord of vegetation changes in the Ama zon region.

Key Words: Carbon isotopes • soil organic matter • cerrado-forest ecosystem • vegetation changes • Rondonia state • Amazon region • Holocene

The Holocene, Vol. 8, No. 5, 599-603 (1998)
DOI: 10.1191/095968398673187182


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				L. C.R. Pessenda, R. Boulet, R. Aravena, V. Rosolen, S. E.M. Gouveia, A. S. Ribeiro, and M. Lamotte Origin and dynamics of soil organic matter and vegetation changes during the Holocene in a forest-savanna transition zone, Brazilian Amazon region The Holocene, February 1, 2001; 11(2): 250 - 254. [Abstract] [PDF]

				J. Mistry Savannas Progress in Physical Geography, December 1, 2000; 24(4): 601 - 608. [PDF]

				M. E. Meadows Biogeography: changing places, changing times Progress in Physical Geography, June 1, 1999; 23(2): 257 - 270. [PDF]