Understanding the Influences of Spatial Patterns on N Availability Within the Brazilian Amazon Forest

Autor(es)

Nardoto, Gabriela Bielefeld ^[1] ; Henry Balbaud Ometto, Jean Pierre ^[1] ; Ehleringer, James R. ^[2] ; Higuchi, Niro ^[3] ; da Cunha Bustamante, Mercedes Maria ^[4] ; Martinelli, Luiz Antonio ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Ctr Energia Nucl Agr, BR-13416000 Piracicaba, SP - Brazil

^[2] Univ Utah, Dept Biol, SIRFER, Salt Lake City, UT 84112 - USA

^[3] Inst Nacl de Pesquisas da Amazonia, BR-69083000 Manaus, Amazonas - Brazil

^[4] Univ Brasilia, Dept Ecol, BR-70919970 Brasilia, DF - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ECOSYSTEMS; v. 11, n. 8, p. 1234-1246, DEC 2008.
• Citações Web of Science: 51

Resumo

Nitrogen variations at different spatial scales and integrated across functional groups were addressed for lowland tropical forests in the Brazilian Amazon as follows: (1) how does N availability vary across the region over different spatial scales (regional x landscape scale); ( 2) how are these variations in N availability integrated across plant functional groups ( legume 9 non-legume trees). Leaf N, P, and Ca concentrations as well the leaf N isotope ratios (delta(15)N) from a large set of legume and non-legume tree species were measured. Legumes had higher foliar N/Ca ratios than non-legumes, consistent with the high energetic costs in plant growth associated with higher foliar P/Ca ratios found in legumes than in non-legumes. At the regional level, foliar delta(15)N decreased with increasing rainfall. At the landscape level, N availability was higher in the forests on clayey soils on the plateau than in forests on sandier soils. The isotope as well as the non-isotope data relationships here documented, explain to a large extent the variation in delta(15)N signatures across gradients of rainfall and soil. Although at the regional level, the precipitation regime is a major determinant of differences in N availability, at the landscape level, under the same precipitation regime, soil type seems to be a major factor influencing the availability of N in the Brazilian Amazon forest. (AU)

• Processo FAPESP: 01/09984-6 - O papel das leguminosas em dois ecossistemas tropicais - Amazônia e Cerrado - utilizando-se a técnica isotópica
• Beneficiário: Gabriela Bielefeld Nardoto
• Modalidade de apoio: Bolsas no Brasil - Doutorado