HR: 17:45h
AN: H54C-08    [Abstracts]
TI: Wet-Season Throughfall in Primary and Secondary Tropical Montane Cloud Forests, Monteverde, Costa Rica
AU: * Guswa, A J
EM: aguswa@email.smith.edu
AF: Picker Engineering Program, 51 College Lane Smith College, Northampton, MA 01063 United States
AU: Rhodes, A L
EM: arhodes@email.smith.edu
AF: Department of Geology, Smith College, Northampton, MA 01063 United States
AB: From June 11 through July 23, 2004 throughfall was recorded four times per week at two sites in Monteverde, Costa Rica on the leeward side of the Cordillera de Tilaran. Each site comprised a regular grid of collectors that were not moved during the collection period and a set of roving collectors that were moved weekly. At one site, twenty-two collectors were spread over 144 m$^2$ in a primary tropical montane cloud forest. At the second site, thirty-two collectors were spaced over 192 m$^2$ in a secondary forest. Summed for the period of collection, open rainfall is 302 mm, mean throughfall at the primary forest site is 240 mm (80% of gross precipitation), and mean throughfall at the secondary forest site is 191 mm (63% of gross precipitation). Standard deviations of total throughfall among the regular grids of collectors are 114 mm for the primary forest (CV = 48%) and 57 mm for the secondary forest (CV = 30%). Histograms of throughfall at each site show positively skewed distributions with a few collectors receiving high volumes of water. Collectors that received high volumes of throughfall for one event, tended to receive high volumes for all events. This persistence indicates canopy and vegetation control of the spatial distribution of throughfall. Throughfall depths show weak correlation to percent canopy and understory cover, distance to nearest tree bole, and diameter of nearest tree, however. Variograms constructed for weekly throughfall totals indicate very short correlation lengths. The short correlation scale and lack of correlation between throughfall and tree location indicates that a random placement of gauges is appropriate for estimating throughfall in these environments.
DE: 1851 Plant ecology
DE: 1854 Precipitation (3354)
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting