Biomass production in a tallgrass prairie ecosystem exposed to ambient and eelevated CO[sub 2]

Journal Article · Mon Nov 01 00:00:00 EST 1993 · Ecological Applications; (United States)

DOI:https://doi.org/10.2307/1942097· OSTI ID:5475870

Owensby, C E; Coyne, P I; Ham, J M; Auen, L M; Knapp, A K ^[1]

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1. Kansas State Univ., Manhattan, KS (United States)

Responses to elevated CO[sub 2] have not been measured for natural grassland ecosystems. Global carbon budgets will likely be affected by changes in biomass production and allocation in major terrestrial ecosystems. Whether ecosystems sequester or release excess carbon to the atmosphere will partly determine the extent and rate that atmospheric CO[sub 2] concentration rises. Elevated CO[sub 2] also may change plant community species composition and water status. We determined above- and belowground biomass production, plant community species composition, and water status of a tallgrass prairie ecosystem in Kansas exposed to ambient and twice-ambient CO[sub 2] concentrations in open-top chambers during the growing season 1989 through 1991. Dominant species were Andropogon gerardii, A. scoparius, and Sorghastrum nutans (C[sub 4] metabolism) and Poa pratensis (C[sub 3]). Aboveground biomass and leaf area were estimated by periodic sampling throughout the growing season in 1989 and 1990. In 1991, peak biomass and leaf area were estimated by an early August harvest. Relative root production was estimated using root ingrowth bags which remained in place through the growing season. Latent heat flux was simulated with and without water stress. Botanical composition was estimated annually. Compared to ambient CO[sub 2] levels, elevated CO[sub 2] increased production of C[sub 4] grass species, but not of C[sub 3] grass species. Species composition of C[sub 4] grasses did not change, but Poa pratensis (C[sub 3]) declined and C[sub 3] forbs increased in the stand with elevated CO[sub 2] compared to ambient. Open-top chambers appeared to reduce latent heat flux and increase water-use efficiency similar to the elevated CO[sub 2] treatment when water stress was not severe, but under severe water stress, the chamber effect on water-use efficiency under elevated CO[sub 2] apparently has greater impact on productivity irrespective of photosynthetic pathway. 34 refs., 8 figs., 1 tab.

• OSTI ID: 5475870
• Journal Information: Ecological Applications; (United States), Vol. 3:4; ISSN 1051-0761
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CARBON CYCLE
GLOBAL ASPECTS
CARBON DIOXIDE
BIOLOGICAL EFFECTS
ECOLOGICAL CONCENTRATION
RANGELANDS
PLANT GROWTH
SPECIES DIVERSITY
TERRESTRIAL ECOSYSTEMS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ECOSYSTEMS
GROWTH
OXIDES
OXYGEN COMPOUNDS
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