HR: 1330h
AN: B22A-0802    [PDF]
TI: Relating NDVI and WBI to Carbon Flux and Biomass in a Grassland Ecosystem
AU: * Brunelle, S M
EM: sbrunelle@hotmail.com
AF: California State University, Los Angeles Department of Biological Sciences, 5151 State University Dr., Los Angeles, Ca 90032 United States
AU: Moyes, A B
EM: abmoyes@yahoo.com
AF: California State University, Los Angeles Department of Biological Sciences, 5151 State University Dr., Los Angeles, Ca 90032 United States
AU: Houston, S A
EM: shousto@calstatela.edu
AF: California State University, Los Angeles Department of Biological Sciences, 5151 State University Dr., Los Angeles, Ca 90032 United States
AU: Gamon, J A
EM: jgamon@calstatela.edu
AF: California State University, Los Angeles Department of Biological Sciences, 5151 State University Dr., Los Angeles, Ca 90032 United States
AB: This study explored the relationships between spectral reflectance, CO$_{2}$ flux (photosynthesis and respiration), and biomass at Cheseboro Canyon, a grassland dominated ecosystem in the Santa Monica Mountains National Recreation Area, located in Southern California. Field sampling conducted in the winter and spring of 2003 consisted of spectral reflectance measurements, ecosystem CO$_{2}$ flux measurement, and biomass estimation. Two optical indices, Normalized Difference Vegetation Index (NDVI) and Water Band Index (WBI), were derived from reflectance and compared to biomass and CO$_{2}$ flux data (photosynthesis and respiration rates). There were strong correlations between optical indices, (NDVI and WBI), CO$_{2}$ fluxes, and aboveground biomass. Consistently, WBI showed stronger relationships to CO$_{2}$ fluxes (especially respiration) than NDVI. The link between carbon flux and this optical index of water content illustrates the strong control on flux by water status in this ecosystem. Respiration had a strong relationship with both NDVI and WBI, suggesting that ecosystem respiration rates are a reflection of recently-fixed carbon. The strong correlations between these optical indices, CO$_{2}$ flux, and above-ground biomass suggest that spectral reflectance, especially WBI can be used to estimate carbon flux and productivity in this grassland ecosystem.
DE: 0400 Biogeosciences
DE: 1640 Remote sensing
DE: 1694 Instruments and techniques
DE: 1851 Plant ecology
DE: 3322 Land/atmosphere interactions
SC: Biogeosciences [B]
MN: 2003 Fall Meeting