Gary Oates
M.S. Range Management, University of California at Berkeley, anticipated Spring 2004
B.S. Resource Management, University of California at Berkeley, 2002
Agronomy, California State University, Fresno, 1972 – 1974M.S. Thesis Projects:
Trace gas fluxes from grazed and ungrazed spring-fed
wetlands in a California oak savannaThis study relates environmental and anthropogenic (cattle grazing) factors affecting methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) flux in spring-fed wetland ecosystems of California’s foothill oak woodlands. Spring-fed wetlands are small but highly productive systems that form at slope breaks where underlying impervious layers of bedrock or clay intercept the soil surface. Nestled within the annual grassland matrix, they are important as sources of water and green forage for domestic livestock during the California dry season. If managed poorly, spring-fed wetland function and structure may be impacted by overuse. Some of the negative effects of overuse include reduced vegetation cover, alteration of soil characteristics, erosion, and changes in nutrient dynamics. This study attempts to quantify CH4, CO2 and N2O fluxes from these systems and to relate these fluxes to impacts that grazing may have on spring-fed ecosystem function.
Water quality and quantity affected by species composition at the terrestrial-aquatic interfaceResearch examining the effects of climate change on California grasslands has focused on elevated atmospheric CO2 concentrations. Recent work has focused on combinations of elevated CO2, water availability changes, and increased temperature. None have tested both a wet-up and dry-down scenario on both annual grassland and spring-fed wetlands.
Spring-fed wetlands have been characterized as transition zones because of their importance in biogeochemical transformations of nutrients flowing from terrestrial to aquatic ecosystems. Thus their importance in carbon and nutrient dynamics is disproportionate to their individual size and total area. Our objective is to try and determine the effects of altered moisture regimes on species composition and water quality, and does the shift in available moisture affect the ability of spring-fed wetlands to act as a bio-filter. To this end we are monitoring both potential species change at the terrestrial-aquatic interface and the quantity (cubic feet per second) and quality (NO3 concentrations) of water flowing through spring-fed wetland systems.
Related Links:
Water Quality Information Center
Society for Range Management
California Department of Water Resources
Greenhouse Gas Online