Autor(es)

Francisquini, M. I. ; Lima, C. M. ; Pessenda, L. C. R. ; Rossetti, D. F. ; Franca, M. C. ; Cohen, M. C. L.

• Tipo de documento: Artigo Científico
• Fonte: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY; v. 415, p. 14-pg., 2014-12-01.

Resumo

We assess the relation between the contrasting vegetation types of rainforest, open savanna and wooded savanna coexisting in close contact on Marajo Island at the mouth of the Amazon River. Floristic and carbon isotopic characterizations of modern plants were combined with organic matter carbon isotope and grain size records of soil to characterize vegetation evolution at six locations on southeastern and northeastern Marajo Island and its relations to climate changes since the late Pleistocene. C-3 plants contribute 100% of the biomass in the rainforest on post-Barreiras sediments (site 1). No significant vegetation changes are evident in these places since at least similar to 7860 cal yr B.P. Rainforests on paleochannels (sites 4 and 6) are protected from flooding by slightly elevated sandy levee and have flora very similar to site 1. These forests were formed since the early-mid Holocene after channel abandonment C3 grasses are predominant in open savanna areas (sites 4,5 and 6), with less representation in wooded savannas (sites 2 and 3). However, C-4 grasses, despite having fewer species, constitute significant biomass in the wooded (similar to 60%) and open savanna vegetation areas, especially during the dry season. The reconstructions of past vegetation together with the distributions of modern vegetation allow prediction that climate changes to drier conditions can significantly influence the future Marajo Island landscape, likely enabling expansion of C-4 plants in the flooding zone and of trees in the rainforests. (C) 2014 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 06/52173-2 - Dinamica de vegetacao e inferencias climaticas no quaternario tardio na regiao da ilha de marajo, (pa), empregando os isotopos de carbono (12c, 13c, 14c) da materia organica de solos e sedimentos.
• Beneficiário: Claudia Moré de Lima
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 07/03615-5 - Reconstrucao da vegetacao e clima desde o holoceno medio no brasil.
• Beneficiário: Luiz Carlos Ruiz Pessenda
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 04/15518-6 - Integracao de dados biologicos e geologicos no baixo tocantins-ilha do marajo: chave na analise da biodiversidade.
• Beneficiário: Dilce de Fátima Rossetti
• Modalidade de apoio: Auxílio à Pesquisa - Regular