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In situ responses to elevated CO 2 in tropical forest understorey plants
Author(s) -
WÜrth M. K. R.,
Winter K.,
KÖrner CH.
Publication year - 1998
Publication title -
functional ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 154
eISSN - 1365-2435
pISSN - 0269-8463
DOI - 10.1046/j.1365-2435.1998.00278.x
Subject(s) - biology , understory , biomass (ecology) , botany , competition (biology) , horticulture , canopy , ecology
1. Plants growing in deep shade and high temperature, such as in the understorey of humid tropical forests, have been predicted to be particularly sensitive to rising atmospheric CO 2 . We tested this hypothesis in five species whose microhabitat quantum flux density (QFD) was documented as a covariable. After 7 (tree seedlings of Tachigalia versicolor and Beilschmiedia pendula ) and 18 months (shrubs Piper cordulatum and Psychotria limonensis, and grass Pharus latifolius ) of elevated CO 2 treatment ( c. 700 μl litre –1 ) under mean QFD of less than 11 μmol m –2 s –1 , all species produced more biomass (25–76%) under elevated CO 2 . 2. Total plant biomass tended to increase with microhabitat QFD (daytime means varying from 5 to 11μmol m –2 s –1 ) but the relative stimulation by elevated CO 2 was higher at low QFD except in Pharus . 3. Non‐structural carbohydrate concentrations in leaves increased significantly in Pharus (+ 27%) and Tachigalia (+ 40%). 4. The data support the hypothesis that tropical plants growing near the photosynthetic light compensation point are responsive to elevated CO 2 . An improved plant carbon balance in deep shade is likely to influence understorey plant recruitment and competition as atmospheric CO 2 continues to rise.