Isotopic view of vegetation and carbon and nitrogen cycles in a cerrado ecosystem, southeastern Brazil

Authors

  • Luciana Della Coletta USP; CENA; Lab. de Ecologia Isotópica
  • Gabriela Bielefeld Nardoto USP; CENA; Lab. de Ecologia Isotópica
  • Sabrina Ribeiro Latansio-Aidar IBt; SMA; Instituto de Botânica
  • Humberto Ribeiro da Rocha USP; IAG; Depto. de Ciências Atmosféricas

DOI:

https://doi.org/10.1590/S0103-90162009000400006

Keywords:

cerrado, carbon, nitrogen, stable isotopes, woody savanna

Abstract

Carbon and nitrogen biogeochemical cycles in savannas are strongly regulated by the seasonal distribution of precipitation and pulses of nutrients released during the wetting of the dry soil and are critical to the dynamics of microorganisms and vegetation. The objective of this study was to investigate the spatial and temporal variability of C and N isotope ratios as indicators of the cycling of these elements in a cerrado sensu stricto area, within a protected area in a State Park in the state of São Paulo, Brazil. The foliar δ13C and δ15N values varied from -33.6 to -24.4 and -2.5 to 4.5 , respectively. The δ13C values showed a consistent relationship with canopy height, revealing the importance of structure of the canopy over the C isotopic signature of the vegetation. Carbon isotopic variations associated with the length of the dry season indicated the importance of recent fixed C to the integrated isotopic signature of the leaf organic C. The studied Cerrado species showed a depleted foliar δ15N, but a wide range of foliar Nitrogen with no difference among canopy heights. However, seasonal variability was observed, with foliar δ15N values being higher in the transition period between dry and rainy seasons. The variation of the foliar C and N isotope ratios presented here was consistent with highly diverse vegetation with high energy available but low availability of water and N.

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Published

2009-08-01

Issue

Section

Crop Science

How to Cite

Isotopic view of vegetation and carbon and nitrogen cycles in a cerrado ecosystem, southeastern Brazil . (2009). Scientia Agricola, 66(4), 467-475. https://doi.org/10.1590/S0103-90162009000400006