Sudderth, Erika A , St.Clair, Samuel B , Salve, Rohit , Fischer, Marc L , Kleber, Marcus , Sudderth, Erik B , Torn, Margaret S , Ackerly, David D. .
Responses to global change: Soil type controls the impact of altered precipitation pattern on ecosystem function in Avena barbata grasslands.
In California grasslands climate models project either increases or decreases in annual precipitation. These changes in total precipitation will alter the frequency and duration of wet and dry spells in ways that are critical for plant and soil processes, but are difficult to predict. We have used a mesocosm experiment to examine how changing precipitation may alter ecosystem function in monospecific stands of the annual grass, Avena barbata. We compared plant and ecosystem responses to low and high rain treatments on a Haplustoll soil collected from Southern California (Sedgwick Reserve), and a Haplustept soil collected from Northern California (Hopland Experimental Station). The rain and soil treatments produced large differences in soil water content, but moisture differences had smaller than expected effects on leaf photosynthesis and ecosystem CO2 and H2O fluxes. Soil type had even larger impacts than the rain treatments on certain ecosystem processes including biomass production and ecosystem respiration. We also observed complex effects of the soil and rain treatments on phenology and productivity. Under increased precipitation, A. barbata flowered later and produced more biomass but less seed when growing on Sedgwick soil. However, when growing on Hopland soil under high precipitation, Avena flowered earlier while producing more biomass and dramatically more seed. Our results demonstrate that edaphic factors are a critical determinant of the impacts that changing climate conditions have on ecosystem processes.
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1 - University of California, Berkeley, Integrative Biology, Berkeley, CA, 94720, USA
2 - Brigham Young University, Plant and Wildlife Sciences, 287 Widtsoe Building, Provo, Utah, 84602 , United States
3 - Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA, 94704, USA
4 - Lawrence Berkeley National Laboratory, Earth Science Division, Berkeley, CA
, 94720, USA
5 - Oregon State University, Crop and Soil Science, Corvallis, OR, 97331, USA
6 - University of California, Berkeley, Electrical Engineering and Computer Science, Berkeley, CA, 94720, USA
7 - Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA, 94720, USA
8 - UC Berkeley, Integrative BIology
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood A/Snowbird Center
Date: Monday, July 27th, 2009
Time: 9:30 AM