HR: 1340h
AN: H53E-0527    [Abstracts]
TI: Precipitation Pulses in a Saltcedar Community: Are They Important?
AU: * Owens, M K
EM: m-owens@tamu.edu
AF: Texas Agricultural Experiment Station, 1619 Garner Field Road, Uvalde, TX 78801 United States
AU: Moore, G W
EM: gwmoore@tamu.edu
AF: Department of Rangeland Ecology & Management Texas A&M University, TAMU 2126, College Station, TX 77843 United States
AU: Ayala, R
EM: rayala@tamu.edu
AF: Texas Agricultural Experiment Station, 1619 Garner Field Road, Uvalde, TX 78801 United States
AB: The size and frequency of precipitation pulses in semiarid communities can be critical for the growth and survival of upland plants. Less is known about the importance of pulse events for plants growing in semiarid riparian areas near free-standing water. Saltcedar (Tamarix ssp.) is an introduced, invasive plant that dominates riparian corridors in the southwestern US but that rarely establishes in upland sites. The importance of precipitation pulses was evaluated by monitoring sap flux at 2 locations using a heat dissipation approach. Twelve trees at each location were monitored over the 2005 growing season to encompass a variety of antecedent soil moisture and precipitation events. The trees were on a gradient from the river edge to the upland plant community. Independent rainfall events (range from 3 - 48 mm) from site 1 (n = 14) and site 2 (n = 10) were analyzed to determine the magnitude and duration of increased sap flux after each event. During and immediately after a rainfall event, sap flux was depressed compared to pre-rainfall conditions. Increases in sap flux after the rainfall were slight and did not persist for long although the duration of increased sap flux was directly related to the size of the pulse event. Analysis of how changes in environmental conditions (primarily air temperature and vapor pressure deficit) associated with precipitation affect sap flux are critical to understand how these plants react to pulse events.
DE: 1813 Eco-hydrology
DE: 1851 Plant ecology (0476)
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: Fall Meeting 2005