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Carbon isotope discrimination by a sequence of Eucalyptus species along a subcontinental rainfall gradient in Australia
Author(s) -
MIller J. M.,
Williams R. J.,
Farquhar G. D.
Publication year - 2001
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.1365-2435.2001.00508.x
Subject(s) - biology , eucalyptus , photosynthesis , botany , ecology
1. The 13 C/ 12 C discrimination (Δ) by a series of co‐occurring and replacement Eucalyptus species was measured across an eightfold decrease in rainfall. As Δ is a measure of the stomatal limitation on photosynthesis, it should provide a subcontinental scale measure of water‐limited plant physiological performance. 2. Leaf Δ of five of 13 species decreased with decreasing rainfall, seven exhibited no trend, and one increased. Wood Δ decreased in eight species, showed no trend in four, and increased in one species. 3. Species replacements were marked by a shift in Δ reflecting greater stomatal limitation on carbon assimilation. 4. Wood Δ was less variable than leaf Δ. 5. There was a non‐linear response of the multispecies average leaf and wood Δ to decreasing total annual rainfall. This response reflected the spatial pattern of the sensitivities of Δ to decreasing rainfall of the individual species. It was not the result of a proposed emergent behaviour where the trend in the multispecies average differed from that of the individual species. 6. Patterns of Δ across the distributions of species (reflecting increasing stomatal limitation on assimilation) did not provide a simple measure of the physiological limits of the distribution of eucalypts in north‐western Australia.