HR: 0800h
AN: B21D-0918    [Abstracts]
TI: Examining Influence of Fog and Stratus Clouds on Bishop Pine Water Budgets, Channel Islands, CA
AU: * Fischer, D T
EM: fischer@geog.ucsb.edu
AF: University of California, Santa Barbara, Dept of Geography 3611 Ellison Hall, Santa Barbara, CA 93106 United States
AU: Still, C J
EM: still@icess.ucsb.edu
AF: University of California, Santa Barbara, Dept of Geography 3611 Ellison Hall, Santa Barbara, CA 93106 United States
AU: Williams, A P
EM: williams@geog.ucsb.edu
AF: University of California, Santa Barbara, Dept of Geography 3611 Ellison Hall, Santa Barbara, CA 93106 United States
AB: We present the first results from a project whose goal is to advance our basic understanding of the role that fog and persistent stratus clouds play in ecological processes in the California Channel Islands. Our work is focused on a population of Bishop Pines ({\it Pinus muricata}) on Santa Cruz Island (SCI), the largest, most topographically complex and most biologically diverse island along the California coast. This is the southernmost population (except for an outlier stand near San Vicente, Baja California), and tree growth appears to be water-limited in such a marginal habitat. We hypothesize that persistent fog and low stratus clouds enhance the water balance of these trees via direct water inputs (fog drip and foliar absorption) and reduced solar heating. To assess these possible effects, we have established weather stations and fog and rain collectors throughout the largest Bishop pine stand on SCI. Initial analysis of weather data shows dramatic differences in solar loading over short distances. We present data on the isotopic content (oxygen-18 and hydrogen-2) of water samples collected from winter 2003 to summer 2004. The samples we collected include fogwater, rainfall, water vapor, soil water, leaf and xylem water, and stream water. We also collected and analyzed leaf biomass and soil organic matter samples at periodic intervals for carbon-13 content. These latter data are evaluated in light of extensive leaf-level ecophysiological data collected in the field and as part of a parallel greenhouse study.
DE: 3307 Boundary layer processes
DE: 1655 Water cycles (1836)
DE: 1818 Evapotranspiration
DE: 1836 Hydrologic budget (1655)
DE: 1851 Plant ecology
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting