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Carbon isotope discrimination by a sequence of Eucalyptus species along a subcontinental rainfall gradient in Australia
Article first published online: 20 DEC 2001
Volume 15, Issue 2, pages 222–232, April 2001
How to Cite
MIller, J. M., Williams, R. J. and Farquhar, G. D. (2001), Carbon isotope discrimination by a sequence of Eucalyptus species along a subcontinental rainfall gradient in Australia. Functional Ecology, 15: 222–232. doi: 10.1046/j.1365-2435.2001.00508.x
- Issue published online: 20 DEC 2001
- Article first published online: 20 DEC 2001
- plant distributions;
- savanna trees;
- species distributions;
- stress tolerance;
- water-use efficiency
1. The 13C/12C 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.