title: Spatial and temporal variation in carbon isotope discrimination in prairie graminoids.
abstract: We present the results of a 5-year examination of variation in the stable carbon isotope composition (δ) of three C3graminoid species from a Sandhills prairie: Agropyron smithii, Carex heliophila and Stipa comata. Although consistent species-specific patterns for mean δ were seen, there was also significant and substantial among-year and within-season variation in δ. A smaller contribution to variation in δ came from topographic variation among sampling sites. Effects of species, year, season and topography contribute to variation in δ in an additive manner. An association between climate and δ exists that is consistent with previous work suggesting that δ reflects the interplay between photosynthetic gas exchange and plant water relations. Within the growing season, the time over which δ integrates plant response to the environment ranges from days to months.
authors.affiliation: School of Biological Science, University of Nebraska-Lincoln, 68588-0118, Lincoln, NE, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Mole
authors.affiliation: School of Biological Science, University of Nebraska-Lincoln, 68588-0118, Lincoln, NE, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Joern
authors.affiliation: Center for Biological Chemistry, University of Nebraska-Lincoln, 68583-0718, Lincoln, NE, USA.
authors.forename: Marion H
authors.initials: MH
authors.lastname: O'Leary
authors.affiliation: Center for Biological Chemistry, University of Nebraska-Lincoln, 68583-0718, Lincoln, NE, USA.
authors.forename: S
authors.initials: S
authors.lastname: Madhavan
keywords: Agropyron smithii Carex heliophila; Carbon isotope discrimination; Sandhills grassland; Stipa comata