HR: 0800h
AN: B51C-0968    [Abstracts]
TI: Carbon Dioxide Exchange in Live Oak-Ashe Juniper Forest and C4 Grassland Ecosystems on the Edwards Plateau, Texas (Texas Hill Country)
AU: * Kjelgaard, J F
EM: jkjelgaard@ag.tamu.edu
AF: Soil and Crop Sciences Texas A&M University, 2474 TAMU, College Station, TX 77843-2474 United States
AU: Heilman, J
EM: j-heilman@tamu.edu
AF: Soil and Crop Sciences Texas A&M University, 2474 TAMU, College Station, TX 77843-2474 United States
AU: McInnes, K
EM: k-mcinnes@tamu.edu
AF: Soil and Crop Sciences Texas A&M University, 2474 TAMU, College Station, TX 77843-2474 United States
AU: Owens, M K
EM: m-owens@tamu.edu
AF: Uvalde-Texas A&M University Agricultural Research and Extension Center, 1619 Garner Field Road, Uvalde, TX 78801-6205 United States
AB: A recent ecoregion-scale analysis of the Ameriflux network indicated that ecosystem/environment combinations in central and south Texas were not represented by the current network of eddy flux towers. The Edwards Plateau (Texas Hill Country) is a large (93,000 km2), distinct ecoregion in south and west central Texas that is a biological crossroads for three major biomes of North America (grassland, desert, deciduous forest). Extensive portions of the Plateau are dominated by live oak-Ashe juniper savannas underlain by C4 grasslands. Currently, grasslands are disappearing due to encroachment by juniper. A long-term comparative study was begun in 2004 to quantify fluxes, sources, and sinks of atmospheric CO2 on the Edwards Plateau, and to determine how encroachment by Ashe juniper alters CO2 fluxes and CO2 source/sink relationships. Meteorological towers for eddy covariance measurements of CO2 exchange were installed on C4-dominated grassland and live oak/Ashe juniper forest sites, representing non-encroachment and full-encroachment conditions. Preliminary results of CO2 exchange in the two ecosystems during the summer and fall of 2004 will be presented and compared with an emphasis on the response of the two ecosystems to rainfall and water deficit conditions.
DE: 3322 Land/atmosphere interactions
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting