| Abstract Detail
Physiological Section Limm, Emily [1], Simonin, Kevin [1], Mambelli, Stefania [1], Dawson, Todd [2]. The Strong Influence of Fog on Western Sword Fern (Polystichum munitum) Hydrology. Western sword fern (Polystichum munitum) is a dominant understory species in the coast redwood forest ecosystem of northern California. During the summer rainless months, frequent nocturnal marine fog provides a water subsidy to the forest that falls onto sword fern canopies as occult precipitation after condensing in the overstory trees above. We measured the physiological performance of multiple sword fern plants every six weeks during the growing season of 2007 at an old-growth redwood forest in Occidental, CA. We determined that the water status of this understory species closely tracks fog water inputs into the forest. Sword fern exhibited the highest water potentials of the year during the peak fog season (-0.19 MPa ± 0.02), exceeding spring water potentials (-0.76 MPa ± 0.24) when residual rainwater in the soil was the only source of water. Sword fern hydrates immediately in response to fog exposure even without fog drip into the soil because this species readily absorbs fog water into its canopy via foliar uptake. Through a greenhouse experiment, we investigated if nocturnal foliar uptake of fog water by sword fern could maintain plant hydration over time while soil water deficit increased. After 3 consecutive nights of fog exposure when drip into the soil was excluded, plants receiving high-intensity fog at night showed improved water potentials (0.31 MPa ± 0.17 increase) as did plants receiving low-intensity fog exposure (0.21 MPa ± 0.12 increase). In contrast, plants that received no fog exposure at night suffered without a water subsidy and water potentials decreased during the experiment (0.26 MPa ± 0.24 decrease). Our data suggest that the wet deposition of fog water on the canopies of sword fern provides a water source that improves plant hydration and promotes survival during the summer rainless season in the coast redwood ecosystem. Log in to add this item to your schedule
1 - University of California, Berkeley, Integrative Biology, 3060 Valley Life Sciences Bldg. #3140, Berkeley, CA, 94720, USA 2 - University of California, Berkeley, Department of Integrative Biology, 3060 Valley Life Sciences Bldg #3140, Berkeley, California, 94720, USA
Keywords: ecophysiology Fern fog water potential foliar uptake redwood forest.
Presentation Type: Oral Paper:Papers for Sections Session: 38 Location: 101/Law Date: Tuesday, July 29th, 2008 Time: 11:15 AM Number: 38007 Abstract ID:293 |