HR: 16:20h
AN: B34A-02 INVITED     [Abstracts]
TI: Influence of Land Use Change on Ecosystem and Landscape Carbon and Water Fluxes in Complex Mountainous Terrain of Stubai Valley, Austria
AU: * Tenhunen, J
EM: john.tenhunen@uni-bayreuth.de
AF: Department of Plant Ecology, University of Bayreuth, Bayreuth, 95440 Germany
AU: Tappeiner, U
B34A-02 AF: Botanical Institute, University of Innsbruck, Innsbruck, 6020 Austria
AU: Geyer, R
B34A-02 AF: Department of Plant Ecology, University of Bayreuth, Bayreuth, 95440 Germany
AU: Cernusca, A
B34A-02 AF: Botanical Institute, University of Innsbruck, Innsbruck, 6020 Austria
AB: Land use in the European Alps has changed during past decades in response to changing economic pressures, leading to abandonment of grazing meadows, especially at high elevation, and expansion of forests. The consequences of these changes in land use are difficult to visualize in their entirety due to the complex response of natural ecosystems to both strong climate gradients in the Alps and to management measures. Landscape level modelling is described for the Stubai Valley in Austria in which the influence of climate gradients and land use on GPP, ecosystem respiration, NEE and water use (taking into account the strong influences of mountainous terrain on radiation input) is quantified. The core model estimates from valley to high elevation sites concurrent changes in carbon dioxide exchange, in aboveground biomass, in leaf area index, in allocation of photoproducts to the belowground ecosystem compartment, and in water use. Currently, simulations are for single years, assuming no significant growth or changes in LAI in evergreen coniferous forests. The Stubai Valley in Austria has provided an advantageous location for first landscape level simulations of carbon and water balances due to long-term studies of process variation along elevation gradients at this location. Results suggest that land use change between 1861 and the present have decreased landscape evapotranspiration to ca. 85 percent of previous levels due to stomatal closure and lower exchange capacity of forests. During the same period, carbon dioxide uptake is estimated to increase by 20 percent on a m2 basis in all vegetation classes. From the landscape perspective, CO2 uptake remained the same, however, due to compensation via land use change. The larger area of grasslands in 1861 produced 30 percent more biomass for harvest despite constant levels in landscape CO2 exchange. The role of remote sensing with respect to model parameterization and validation is discussed, as are potential applications of the model in the evaluation of future land use change defined via stakeholder evaluations of economic scenarios or economic models.
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