Urea additions and defoliation affect plant responses to elevated CO2 in a C3 grass from Yellowstone National Park
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Authors: B. J. Wilsey
Date: 1996
Journal: Oecologia
Volume: 108
Number: 321-327
Pages: 321-327
Summary of Methods: The total biomass response of Stipa occidentalis to elevated CO2 was similar (averaging 18% increase in biomass) to the response found for other grassland species. However, the increase in total biomass, in response to elevated CO2, was dependent on plants not being clipped and receiving urea treatments. Increases in growth as a response to elevated CO2 occurred primarily in crowns, which can serve a storage function in grasses. Plants in Yellowstone National Park evolved in the presence of grazing mammals, but do not exhibit a plastic response to urea treatments. S. occidentalis, which was collected from a high elevation grassland within Yellowstone, could be constrained by the evolution of a slow growth rate and, thus, lack the response to urea. Clipping resulted in increases in aboveground productivity, but also caused a decrease in crown biomass. Since there was no large increases in aboveground biomass, the quantity of forage available to grazers remains unaffected by elevated CO2 levels. Authors suggest that elevated atmospheric CO2 concentrations negatively affect grazing mammals, due to the observed decrease in forage N content, without increase to forage quantity.
Article Summary / Main Points: None
Vegetation Types:
MLRA Ecoregions:
Agrovoc Control Words: Riparian zones Rangelands Wildlife
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: stipa occidentalis, grazing, herbivory, co2 enrichment, global change, grasslands, yellowstone national park
Annotation: Plants were collected in October from the field and then were put into dormancy. After one month, plants were brought out of dormancy and potted. On day 87, plants were harvested.
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