Influence of land-use change on near-surface hydrological processes: Undisturbed forest to pasture

Autor(es)

Germer, Sonja ^[1] ; Neill, Christopher ^[2] ; Krusche, Alex V. ^[3] ; Elsenbeer, Helmut ^[4]

Afiliação do(s) autor(es)

^[1] Berlin Brandenburg Acad Sci & Humanities, D-10117 Berlin - Germany

^[2] Marine Biol Lab, Ctr Ecosyst, Woods Hole, MA 02543 - USA

^[3] Univ Sao Paulo, Ctr Energia Nucl Agr, BR-13400970 Piracicaba, SP - Brazil

^[4] Univ Potsdam, Inst Geoecol, D-14476 Golm - Germany

• Tipo de documento: Artigo Científico
• Fonte: Journal of Hydrology; v. 380, n. 3-4, p. 473-480, Jan. 2010.
• Citações Web of Science: 98
• Assunto(s): Escoamento superficial Lençóis freáticos Desmatamento Ecossistema amazônico

Resumo

Soil compaction that follows the clearing of tropical forest for cattle pasture is associated with lower soil hydraulic conductivity and increased frequency and volume of overland flow. We investigated the frequency of perched water tables, overland flow and stormflow in an Amazon forest and in an adjacent 25-year-old pasture cleared from the same forest. We compared the results with the frequencies of these phenomena estimated from comparisons of rainfall intensity and soil hydraulic conductivity. The frequency of perched water tables based on rainfall intensity and soil hydraulic conductivity was expected to double in pasture compared with forest. This corresponded closely with an approximate doubling of the frequency of stormflow and overland flow in pasture. In contrast, the stormflow volume in pasture increased 17-fold. This disproportional increase of stormflow resulted from overland flow generation over large areas of pasture, while overland flow generation in the forest was spatially limited and was observed only very near the stream channel. In both catchments, stormflow was generated by saturation excess because of perched water tables and near-surface groundwater levels. Stormflow was occasionally generated in the forest by rapid return flow from macropores, while slow return flow from a continuous perched water table was more common in the pasture. These results suggest that deforestation for pasture alters fundamental mechanisms of stormflow generation and may increase runoff volumes over wide regions of Amazonia. (C) 2009 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 03/13172-2 - O papel dos sistemas fluviais amazônicos no balanço regional e global de carbono: evasão de CO2 e interações entre os ambientes terrestres e aquáticos
• Beneficiário: Reynaldo Luiz Victória
• Modalidade de apoio: Auxílio à Pesquisa - Temático