The ontogeny of individual vs. stand-level responses to elevated CO[sub 2]

Conference · Wed Jun 01 00:00:00 EDT 1994 · Bulletin of the Ecological Society of America; (United States)

OSTI ID:7272304

Thomas, S C; Jasienski, M; Bazzaz, F A ^[1]

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1. Harvard Univ., Cambridge, MA (United States)

Plant species appear to differ widely in terms of growth responses to elevated CO[sub 2]; however, most existing comparative data are limited to observations made early in the ontogeny on plants grown an isolated individuals. We examined growth responses to elevated CO[sub 2] in nine species of herbaceous plants, including three erect annuals (genera included Abutilon, Ambrosia, and Cassia) three grasses (Dactylis, Lolium, Panicum), and three rosette species (Plantago, Rumex, and Taraxacum), each grown as isolated individuals and as dense monocultures in ambient (350 ppm) and 2X ambient (700 ppm) CO[sub 2] atmospheres in a glasshouse over 5-6 mo. Soil texture, depth, and nutrient conditions matched those of waste areas in western Massachusetts. On the basis of non-destructive estimates of leaf area index (LAI), all species exhibited large early growth responses to CO[sub 2], ranging up to 50-120%. However, later in stand ontogeny LAI consistently converged between CO[sub 2] treatments, eventually becoming lower at ambient than at elevated CO[sub 2] in most species. Final total biomass effects at the stand level were in the range of 0-10% enhancements, with no consistent differences among growth forms. Reproductive output was significantly reduced by elevated CO[sub 2] in several species, including some with very high early growth enhancements. Our results strongly suggest that CO[sub 2] effects on early growth of individual plants greatly overestimate longer term effects on species performance and net ecosystem carbon gain.

• OSTI ID: 7272304
• Report Number(s): CONF-940894-; CODEN: BECLAG
• Journal Information: Bulletin of the Ecological Society of America; (United States), Vol. 75:2; Conference: Annual Ecological Society of America (ESA) meeting: science and public policy, Knoxville, TN (United States), 7-11 Aug 1994; ISSN 0012-9623
• Country of Publication: United States
• Language: English

Related Subjects

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CARBON DIOXIDE
BIOLOGICAL EFFECTS
ECOLOGICAL CONCENTRATION
PLANTS
PLANT GROWTH
REPRODUCTION
GRAMINEAE
HERBS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
GROWTH
LILIOPSIDA
MAGNOLIOPHYTA
OXIDES
OXYGEN COMPOUNDS
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