PARENT SESSION
Contributed Oral Session 76: Estuary and Coastal Management
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 514 A, Level 5, Palais des congrès de Montréal
Non-destructive methods for estimating productivity of vegetation in tidal marshes of San Francisco Bay, California.
Schile, Lisa*,1, Vasey, Michael1, Callaway, John2, Parker, V. Thomas1, 1 Department of Biology, San Francisco, CA, 941322 Environmental Science Department, San Francisco, CA, 94117
ABSTRACT- The study focused on developing highly reliable but non-destructive methods for measuring productivity of dominant plant species in tidal wetlands of northern San Francisco Bay. Four marshes were chosen that varied in seasonal patterns of substrate salinity. Three were located along the Napa River and one just west of the confluence of the Sacramento and San Joaquin Rivers. All sites are tidal, but the seasonal peaks in salinity range from close to freshwater to nearly seawater levels. At the end of the growing season in 2004, multiple 0.25 m2 plots were established in stands of the following species: Scirpus maritimus, S. americanus, S. californicus, S. acutus, Typha angustifolia, T. domingensis, and Salicornia virginica. Not all of the species were sampled at each site. Three methodologies were tested against harvested biomass: leaf area index (LAI) measured with a LiCor LAI 2000, average plant height, and individual plant height and stem density. Within each plot, the leaf area index (LAI) and average height per species were measured, and all standing biomass was collected. In the lab, the samples were sorted by species and, for all Scirpus spp, the stem density was counted and plants sorted according to 10 cm height classes. All plants were dried and weighed to determine biomass. Average plant height had no significant relationship with biomass, regardless of species. A significant positive relationship occurred between LAI and biomass for S. virginica, S. virginica/S. maritimus mixed plots, and both Typha species (R2 ranging from 0.71 to 0.81). LAI was not strongly related to biomass for the Scirpus species; however, both stem density and height were significantly correlated to biomass for all four species (R2 ranging from 0.81 to 0.96). These results suggest that accurate non-destructive sampling methods can be developed to estimate species-level productivity. Further testing and modification of these methodologies will occur during the 2005 growing season, including a more in-depth investigation into S. virginica productivity, and site-level productivity estimates will be calculated based on vegetation maps.
Key words: productivity, wetland vegetation, leaf area index, San Francisco Bay