HR: 1340h
AN: H53E-0522    [Abstracts]
TI: Comparison of Regional Water Flux Patterns Across Disparate Species Located Along a Steep Climatic Transect in the Rio Grande Basin.
AU: * White, S
EM: sawhite@nmt.edu
AF: New Mexico Tech, 801 Leroy Pl. #2021, Socorro, NM 87801 United States
AU: Brown, K
EM: kmbrown@lanl.gov
AF: University of California-Santa Barbara, University of California, Santa Barbara, CA 93106 United States
AU: McDowell, N
EM: mcdowell@lanl.gov
AF: Earth and Environmental Sciences Los Alamos Natinoal Laboratory, MS J495, Los Alamos, NM 87545 United States
AU: Powers, H
EM: hpowers@lanl.gov
AF: Earth and Environmental Sciences Los Alamos Natinoal Laboratory, MS J495, Los Alamos, NM 87545 United States
AB: We measured overstory transpiration in three ecosystems in New Mexico located across a steep climatic gradient with the objective of examining environmental and physiological mechanisms by which vegetation impacts the hydrologic cycle of the Rio Grande Basin. Sap flow was measured using the Granier approach on juniper (Juniperus monosperma), ponderosa pine (Pinus ponderosa), and spruce (Picea englemannii) trees located within 40 km of each other over a 1000m elevation transect. Overstory transpiration per tree was slightly higher in ponderosa pine than spruce, both of which were one order of magnitude greater than in juniper. However, transpiration per unit ground area depended largely on overstory leaf area, which followed the order: spruce-pine-juniper. Sensitivity to atmospheric drought also followed this order. Allometric shifts in leaf area to sapwood area may have regulated transpiration per unit leaf area, transpiration per unit ground area, and carbon isotope discrimination. Transpiration in the ponderosa and spruce forests appear coupled to regional climate patterns, however the juniper woodland was independent of regional climatic variation. Ground water access may buffer transpiration from climatic forcing factors.
DE: 1813 Eco-hydrology
DE: 1818 Evapotranspiration
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1851 Plant ecology (0476)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: Fall Meeting 2005