The evolution of a tropical rainforest/grassland mosaic in southeastern Brazil since 28,000 C-14 yr BP based on carbon isotopes and pollen records

Autor(es)

Pessenda, Luiz Carlos Ruiz ^[1] ; Oliveira, Paulo Eduardo de ; Mofatto, Milene ; Medeiros, Vanda Brito de ; Garcia, Ricardo José Francischetti ; Aravena, Ramon ; Bendassoli, José Albertino ; Leite, Acácio Zuniga ; Saad, Antonio Roberto ; Etchebehere, Mario Lincoln

Afiliação do(s) autor(es)

^[1] Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura - Brasil

• Tipo de documento: Artigo Científico
• Fonte: Quaternary Research; v. 71, n. 3, p. 437-452, May 2009.
• Área do conhecimento: Ciências Exatas e da Terra - Geociências
• Assunto(s): Florestas tropicais Pólen Solos Isótopos de carbono

Resumo

The lack of paleoecological records from the montane Atlantic Rainforest of coastal Brazil, a hotspot of biological diversity, has been a major obstacle to our understanding of the vegetational changes since the last glacial cycle. We present carbon isotope and pollen records to assess the impact of the glaciation on the native vegetation of the Serra do Mar rainforest in Sao Paulo, Brazil. From ca. 28,000 to similar to 22,000 C-14 yr BP, a Subtropical forest with conifer trees is indicative of cool and humid conditions. In agreement carbon isotopic data on soil organic matter Suggest the presence of C-3 plants and perhaps C-4 plants from similar to 28,000 to similar to 19,000 C-14 yr BP. The significant increase in the sedimentation rate and algal spores from similar to 19,450 to similar to 19,000 C-14 yr BP indicates increasing humidity, associated to an erosion process between similar to 19,000 and similar to 15,600 C-14 yr BP. From similar to 15,600 C-14 yr. BP to present there is a substantial increase in arboreal elements and herbs, indicating more humid and warmer climate. From, similar to 19,000 to similar to 1000 C-14 yr BP, delta C-13 values indicated the predominance of C-3 plants. These results are in agreement with Studies in speleothems of caves, which suggest humid conditions during the last glacial maximum. (AU)

• Processo FAPESP: 03/03297-2 - Estudo multi/interdisciplinar de reconstrucao da vegetacao e clima na regiao do parque estadual da serra do mar-nucleo curucutu, sao paulo, sp no quaternario tardio.
• Beneficiário: Milene Mofatto
• Modalidade de apoio: Bolsas no Brasil - Mestrado