%0 Journal Article
%@holdercode {isadg {BR SPINPE} ibi 8JMKD3MGPCW/3DT298S}
%@nexthigherunit 8JMKD3MGPCW/3ER446E
%@resumeid 8JMKD3MGP5W/3C9JGTQ
%X Question: How can the coexistence of savanna and forest in Amazonian areas with relatively uniform climates be explained? Location: Eastern Marajo Island, northeast Amazonia, Brazil. Methods: The study integrated floristic analysis, terrain morphology, sedimentology and delta C-13 of soil organic matter. Floristic analysis involved rapid ecological assessment of 33 sites, determination of occurrence, specific richness, hierarchical distribution and matrix of floristic similarity between paired vegetation types. Terrain characterization was based on analysis of Landsat images using 4(R), 5(G) and 7(B) composition and digital elevation model (DEM). Sedimentology involved field descriptions of surface and core sediments. Finally, radiocarbon dating and analysis of delta C-13 of soil profile organic matter and natural ecotone forest-savanna was undertaken. Results: Slight tectonic subsidence in eastern Marajo Island favours seasonal flooding, making it unsuitable for forest growth. However, this area displays slightly convex-up, sinuous morphologies related to paleochannels, covered by forest. Terra-firme lowland forests are expanding from west to east, preferentially occupying paleochannels and replacing savanna. Slack, running water during channel abandonment leads to disappearance of varzea/gallery forest at channel margins. Long-abandoned channels sustain continuous terra-firme forests, because of longer times for more species to establish. Recently abandoned channels have had less time to become sites for widespread tree development, and are either not vegetated or covered by savanna. Conclusion: Landforms in eastern Marajo Island reflect changes in the physical environment due to reactivation of tectonic faults during the latest Quaternary. This promoted a dynamic history of channel abandonment, which controlled a set of interrelated parameters (soil type, topography, hydrology) that determined species location. Inclusion of a geological perspective for paleoenvironmental reconstruction can increase understanding of plant distribution in Amazonia.
%N 1
%T Coexistence of forest and savanna in an Amazonian area from a geological perspective
%@electronicmailaddress rossetti@dsr.inpe.br
%@secondarytype PRE PI
%K Quaternário, Ilha do Marajó, vegetação, DISTRIBUIÇÃO, paleocanais.
%@archivingpolicy denypublisher denyfinaldraft
%@usergroup administrator
%@usergroup lattes
%@usergroup marciana
%@group DSR-OBT-INPE-MCT-BR
%@e-mailaddress rossetti@dsr.inpe.br
%3 rosetti.pdf
%@secondarykey INPE--PRE/
%@secondarymark A2_CIÊNCIAS_AGRÁRIAS_I A2_CIÊNCIAS_BIOLÓGICAS_I A2_ECOLOGIA_E_MEIO_AMBIENTE A2_GEOCIÊNCIAS A2_INTERDISCIPLINAR
%F lattes: 0307721738107549 1 RossettiAlmAmaLimPes:2010:CoFoSa
%@issn 1100-9233
%2 dpi.inpe.br/plutao@80/2010/07.11.14.14.16
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%B Journal of Vegetation Science
%@versiontype publisher
%P 120-132
%4 dpi.inpe.br/plutao@80/2010/07.11.14.14.15
%@documentstage not transferred
%D 2010
%V 21
%@doi 10.1111/j.1654-1103.2009.01129.x
%A Rossetti, Dilce de Fátima,
%A Almeida, Samuel,
%A Amaral, Dário Dantas do,
%A Lima, Claudia More,
%A Pessenda, Luiz C. R.,
%@dissemination WEBSCI; PORTALCAPES.
%@area SRE