HR: 0800h
AN: B41A-0097    [Abstracts]
TI: Abundance of Woody Riparian Species in the Western USA in Relation to Phenology, Climate, and Flow Regime
AU: * Auble, G T
EM: greg\_auble@usgs.gov
AF: U.S. Geological Survey, 2150 Centre Ave., Bldg. C, Fort Collins, CO 80526 United States
AU: Friedman, J M
AF: U.S. Geological Survey, 2150 Centre Ave., Bldg. C, Fort Collins, CO 80526 United States
AU: Scott, M L
AF: U.S. Geological Survey, 2150 Centre Ave., Bldg. C, Fort Collins, CO 80526 United States
AU: Shafroth, P B
AF: U.S. Geological Survey, 2150 Centre Ave., Bldg. C, Fort Collins, CO 80526 United States
AU: Merigliano, M M
AF: University of Montana, School of Forestry, Missoula, MT 59812 United States
AU: Freehling, M D
AF: University of New Mexico, Natural Heritage New Mexico, Albuquerque, NM 87131 United States
AU: Evans, R E
AF: Johnson Controls World Service, Inc., 2150 Centre Ave., Bldg. C, Fort Collins, CO 80526 United States
AU: Griffin, E R
AF: U.S. Geological Survey, 3215 Marine Street, Suite E-127, Boulder, CO 80303 United States
AB: We randomly selected 475 long-term U.S. Geological Survey stream gaging stations in 17 western states to relate the presence and abundance of woody species to environmental factors. Along a 1.3-km reach near each station we measured the cover of all species on a list of the 44 most abundant large woody riparian species in the region. We used logistic regression to fit the response of four abundant species to growing degree days and mean precipitation. Then we related relative abundance of these 4 species to timing of the flood peak in sites where the likelihood of occurrence was greater than 0.5. The exotics {\it Tamarix ramosissima} (saltcedar) and {\it Elaeagnus angustifolia} (Russian-olive) are now the third and fourth most frequently occurring large woody riparian species in the western U.S. and the second and fifth most abundant. In climatically suitable areas, species differences in reproductive phenology produce different relations of abundance to flow regime. Because of its limited period of seed release and viability in early summer, cottonwood ({\it Populus deltoides}) is disadvantaged where floods occur in the spring or fall. Abundances of saltcedar, because of its long period of seed release; Russian-olive, because of seed dormancy; and {\it Salix exigua}, because of the importance of vegetative spread, are much less sensitive to flood timing.
DE: 1821 Floods
DE: 1851 Plant ecology
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting