HR: 11:20h
AN: B52B-05    [Abstracts]
TI: Critical Influences on Carbon Balances and Production in the Man-made Montado Savanna of Portugal
AU: Pereira, J
EM: jspereira@isa.utl.pt
AF: Technical University of Lisbon, Institute of Agronomy Department of Silviculture Tapada da Ajuda, Lisbon, 1349-017 Portugal
AU: * Tenhunen, J
EM: john.tenhunen@uni-bayreuth.de
AF: University of Bayreuth, Department of Plant Ecology, Bayreuth, 95440 Germany
AU: Dinh, N Q
B52B-05 AF: University of Bayreuth, Department of Plant Ecology, Bayreuth, 95440 Germany
AU: Reichstein, M
B52B-05 AF: DISAFRI - University of Tuscia, Dept. of Forest Environment and Resources Via S. Camillo de Lellis, Viterbo, 01100 Italy
AU: Ribeiro, N
B52B-05 AF: University of Evora, Department of Forestry, Evora, 7002-554 Portugal
AB: The "montado savanna" of Portugal provides ecosystem services in the form of cork from Quercus suber trees and understory forage for grazing animals. The production system is controlled directly by physical factors along regional climate and hydrological gradients as well as by human influences on fire, grazing and tree population dynamics (planting and plowing for fire control). We present an analysis of carbon and water exchange at montado savanna sites that is based on long-term eddy covariance measurements, ecophysiological field studies and process-based modelling. A pixel-oriented model set up for spatial simulations, estimates gas fluxes between vegetation and the atmosphere separately for the tree and understory compartments (subsequently combining these), allows for herbage growth and LAI development, and predicts physiological gas exchange restrictions (stomatal regulation) and herb dieback in response to reduced water availability over annual courses. Model validation has been carried out via comparisons with eddy covariance observations at the MITRA II site in Evora, Portugal. Ground level observations of ecosystem structure (LAI and tree cover), aerial photography, Landsat images, and MODIS remotely sensed data are utilized to apply the modelling and to estimate fluxes at landscape, regional and continental scales (Mediterranean basin) for similar vegetation. Potential links to tree growth models and socio-economic models are discussed.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
DE: 0476 Plant ecology (1851)
SC: Biogeosciences [B]
MN: Fall Meeting 2005