title: Distribution of biomass of species differing in photosynthetic pathway along an altitudinal transect in southeastern wyoming grassland.
abstract: Based on the physiological characteristics and responses of C3, C4, and CAM plants to environmental factors, it is generally predicted that C4and CAM plants will become more abundant with increasing temperature and decreasing precipitation. To test this prediction, the relative contribution of each photosynthetic type to total plant community biomass was examined at seven study areas along an altitudinal transect in southeastern Wyoming grassland. In going from high (2,652 m) to low (1,405 m) elevation along this transect, mean annual temperature increased and annual precipitation decreased.The percentage of C4biomass composing each study area decreased with increasing elevation, while the percentage of C3biomass increased. All elevations had a significantly higher percentage of C4biomass in August than in June, reflecting the warm season growth characteristic of C4plants. Regressions of relative abundance of photosynthetic types on climatic variables showed that both mean annual temperature and annual precipitation were equally reliable as predictors of C3-C4biomass, although we feel that temperature is of primary importance in explaining our observations. CAM species were present at all elevations, but showed no trends in biomass distribution with respect to elevation.
authors.affiliation: Department of Botany and Range Science, Brigham Young University, 84602, Provo, Utah, USA.|Dept. of Biology, Augustana College, 57197, Sioux Falls, South Dakota, USA.|Dept. of Botany, University of Nairobi, P.O. Box 30197, Nairobi, Kenya.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Boutton
authors.affiliation: School of Life Sciences, University of Nebraska, 68588, Lincoln, Nebraska, USA.
authors.forename: A Tyrone
authors.initials: AT
authors.lastname: Harrison
authors.affiliation: Department of Botany and Range Science, Brigham Young University, 84602, Provo, Utah, USA.|Dept. of Botany, University of Nairobi, P.O. Box 30197, Nairobi, Kenya.
authors.forename: Bruce N
authors.initials: BN
authors.lastname: Smith