The Effects of Tropical Forest Conversion: Ecological Research in the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA)
Marcos Costa UFV - Universidade Federal de Višosa (SA-PI)
Jonathan A. Foley Institute on the Environment (US-PI)
We have proposed a low-cost effort, focused on LBA-ECO research agendas, that will
build upon our ongoing activities in land surface and ecosystem modeling. Our group is
currently funded as an EOS Interdisciplinary Science Team (IDS) by NASA's Mission to
Our group is currently engaged in an effort to develop an integrated dynamical
biosphere model -- the Integrated Biosphere Simulator (IBIS). Our modeling approach
reconciles the disparity of the existing land surface packages and terrestrial biosphere
models by representing a more complete hierarchy of ecosystem phenomena, including:
- land surface physics (energy, water, and momentum exchange within the
- canopy gas exchange (photosynthesis, respiration, and stomatal behavior)
- plant phenology (seasonal cycles of leaf development, leaf senescence, and plant
- whole-plant physiology (allocation of carbon and nitrogen, plant growth, tissue
turnover, and age-dependent changes)
- vegetation dynamics (recruitment, competition for resources, mortality,
disturbances, and gap formation)
- carbon and nitrogen cycling (flow of carbon and nitrogen between the atmosphere,
vegetation, litter, and soils).
Initial versions of IBIS have been used to investigate global patterns of water
balance, carbon cycling, and vegetation cover, as well as the potential impact of
increasing CO2 concentrations on the hydrology of the Amazon basin. We are
developing a more sophisticated version of IBIS for simulations of global biogeochemical
processes, vegetation dynamics, and terrestrial hydrology as part of our funded NASA EOS
Interdisciplinary Science Investigation.
Working with other LBA-ECO investigators, we hope to use our integrated terrestrial
biosphere model to evaluate changes in land surface processes, ecosystem dynamics, and
terrestrial carbon storage in response to land use activities in Amazonia.
We anticipate that these efforts will proceed along four areas:
- Develop an historical perspective of land cover change in Amazonia. Using a
combination of remote sensing products (i.e., Landsat and AVHRR data), long-term national
inventory data, and other ancillary data, one can construct an empirically-based model of
land use activity and land cover conversion for the Amazon basin.
We plan to work with LBA-ECO investigators in developing land use and land cover
change scenarios for the Amazon region. In addition, a graduate student in our group,
Navin Ramankutty, is currently building a land-use model for reconstructing global
patterns of land use and land cover change during the last 100 years. This work could be
extended, at little cost, to focus on the Amazon basin as well.
- Use land use scenarios as a driver of the IBIS dynamic biosphere model. Using our
IBIS dynamic biosphere model, and land cover change scenarios, we can examine the dynamic
processes occurring within terrestrial ecosystems that give rise to carbon sources and
sinks. Using IBIS to simulate dynamic ecosystem processes will provide several advantages
over other modeling approaches, because it simulates land surface processes, canopy
physiology and gas exchanges, biogeochemical cycling, and vegetation dynamics in a single,
physically-consistent modeling framework.
We plan to collaborate with LBA-ECO investigators to develop appropriate simulation
experiments, and to coordinate data exchange and model intercomparison
- Validate model simulations against hierarchical of surface and remotely sensed Working with data generated by LBA projects, we will be able to compare
our simulations of land surface processes and ecosystem dynamics against a full suite of
observations. These observations include (we hope) streamflow data, tower flux data,
isotope samples (i.e., 13C/12C, 18O/16O), and
satellite measures (including data from Landsat, AVHRR, and MODIS). Our integrated
biosphere modeling approach, unlike other modeling frameworks, will facilitate a more
complete validation procedure by linking direct biophysical measures (e.g., canopy
spectral reflectance, energy and water fluxes, and isotopic fractionation) and longer-term
ecological, biogeochemical and hydrological measures (e.g., leaf area index, biomass, soil
carbon, runoff and river discharge).
- Evaluate response of net carbon exchange to land use scenarios. Finally, we will be
able to examine how changes in land use (past, present, and future) may affect the gross
carbon budget of the Amazonian region.
To facilitate communication and collaboration with Brazilian scientists, we will
coordinate our efforts with Prof. Marcos Costa, who is currently working with Foley's
group at Wisconsin. Costa is a Professor in the Department of Agricultural Engineering at
the Federal University of Višosa.