A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...
A Look at Amazon Basin Seasonal Dynamics with the Biophysical ... A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...
Effects of land use change and tree coverage decrease in key aspects of the carbonbudget of the Brazilian Cerrado savanna.Authors: Roberto E. Aduan*; Carlos A. Klink*,& Eric A. Davidson**Adress: Universidade de Brasília, Departamento de Ecologia; Campus Universitário, ICC,Ala Sul; Brasília, DF; Cep: 70910-900e-mail: rengel@unb.br* Universidade de Brasília, Departamento de Ecologia; ** Woods Hole Research CenterThe aim of this study is to evaluate differences in ecosystem carbon budgets amongCerrado vegetation with abundant trees, Cerrado vegetation dominated by native grasses,and formerly Cerrado areas converted to pasture. The work is being conducted in twoCerrado areas (with contrasting tree densities), in the Reserva Ecologica do Roncador(RECOR-IBGE) and in one area converted to pasture, in the Centro de PesquisasAgropecuarias do Cerrado (CPAC-EMBRAPA), both located near Brasilia. We monitoredkey processes related to the carbon dynamics: soil respiration (using the dynamic chamberIRGA technique), litterfall (litterfall collectors) and decomposition (litter decompositionbags). In the woody area, soil respiration rates were similar to other tropical savannas(0.7-0.22gC m -2 h -1 ). The area with lower tree density had similar soil respiration, but withsharper seasonal variation (0.6-0.25gC m -2 h -1 ), lower litterfall (1,5x10 6 gC ha -1 yr -1 versus3.0x10 6 gC ha -1 yr -1 in the woody plot) and lower decomposition rates. The planted pastureshowed higher soil respiration fluxes, with more intense seasonal variation compared to theCerrado plots. The peak of soil respiration activity in the pasture occurred in the beginningof the rainy season, while in the Cerrado areas the peak occurred in the end of this season.The decrease of the arboreal component seems to decrease the carbon cycling in thisecosystem, while the conversion to pasture seems to accelerate the carbon cycling,switching to a less conservative and more seasonably variable ecosystem.
- Page 212: INFLUENCE OF SEASONALITY AND LAND U
- Page 216: Using Eddy Covariance and Bowen Rat
- Page 220: COMPARISION THE SOIL RESPIRATION IN
- Page 224: WATER POTENTIAL OF PLANTS IN DIFFER
- Page 228: CO2 FLUXES OVER PANTANAL REGION UND
- Page 232: Radiation Budget over the forest ne
- Page 236: MODELING INTERCEPTED SOLAR RADIATIO
- Page 240: Tower- and Biometry-based Measureme
- Page 244: A METHODOLOGICAL APPROACH TO STUDY
- Page 248: Ecophysiological characteristics re
- Page 252: Ecological Classification of Soils
- Page 256: C Sequestration Dynamics: Biomass,
- Page 260: Simone PereiraMuseu ParaenseEmílio
- Page 266: The Net Carbon Flux Due to Deforest
- Page 270: Autotrophic X heterotrophic respira
- Page 274: Submitted to: II_ISC_LBA - 2 ND INT
- Page 278: Fine root dynamics from radiocarbon
- Page 282: SEASONAL CHANGES IN LEAF LITTER NUT
- Page 286: Variability of Soil Microbial Bioma
- Page 290: composite. We can also use several
- Page 294: Soil microbial biomass and respirat
- Page 298: Tree ring studies to estimate carbo
- Page 302: Litter decomposition rate estimatio
- Page 306: cardinot@amazon.com.britohver@yahoo
- Page 310: VARIABILITY OF SOIL RESPIRATION OVE
Effects of land use change and tree coverage decrease in key aspects of <strong>the</strong> carbonbudget of <strong>the</strong> Brazilian Cerrado savanna.Authors: Roberto E. Aduan*; Carlos A. Klink*,& Eric A. Davidson**Adress: Universidade de Brasília, Departamento de Ecologia; Campus Universitário, ICC,Ala Sul; Brasília, DF; Cep: 70910-900e-mail: rengel@unb.br* Universidade de Brasília, Departamento de Ecologia; ** Woods Hole Research CenterThe aim of this study is to evalu<strong>at</strong>e differences in ecosystem carbon budgets amongCerrado veget<strong>at</strong>ion <strong>with</strong> abundant trees, Cerrado veget<strong>at</strong>ion domin<strong>at</strong>ed by n<strong>at</strong>ive grasses,and formerly Cerrado areas converted to pasture. The work is being conducted in twoCerrado areas (<strong>with</strong> contrasting tree densities), in <strong>the</strong> Reserva Ecologica do Roncador(RECOR-IBGE) and in one area converted to pasture, in <strong>the</strong> Centro de PesquisasAgropecuarias do Cerrado (CPAC-EMBRAPA), both loc<strong>at</strong>ed near Brasilia. We monitoredkey processes rel<strong>at</strong>ed to <strong>the</strong> carbon dynamics: soil respir<strong>at</strong>ion (using <strong>the</strong> dynamic chamberIRGA technique), litterfall (litterfall collectors) and decomposition (litter decompositionbags). In <strong>the</strong> woody area, soil respir<strong>at</strong>ion r<strong>at</strong>es were similar to o<strong>the</strong>r tropical savannas(0.7-0.22gC m -2 h -1 ). The area <strong>with</strong> lower tree density had similar soil respir<strong>at</strong>ion, but <strong>with</strong>sharper seasonal vari<strong>at</strong>ion (0.6-0.25gC m -2 h -1 ), lower litterfall (1,5x10 6 gC ha -1 yr -1 versus3.0x10 6 gC ha -1 yr -1 in <strong>the</strong> woody plot) and lower decomposition r<strong>at</strong>es. The planted pastureshowed higher soil respir<strong>at</strong>ion fluxes, <strong>with</strong> more intense seasonal vari<strong>at</strong>ion compared to <strong>the</strong>Cerrado plots. The peak of soil respir<strong>at</strong>ion activity in <strong>the</strong> pasture occurred in <strong>the</strong> beginningof <strong>the</strong> rainy season, while in <strong>the</strong> Cerrado areas <strong>the</strong> peak occurred in <strong>the</strong> end of this season.The decrease of <strong>the</strong> arboreal component seems to decrease <strong>the</strong> carbon cycling in thisecosystem, while <strong>the</strong> conversion to pasture seems to acceler<strong>at</strong>e <strong>the</strong> carbon cycling,switching to a less conserv<strong>at</strong>ive and more seasonably variable ecosystem.
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