Variation in δ13C among species and sexes in the family Restionaceae along a fine-scale hydrological gradient
Article first published online: 28 OCT 2010
© 2010 The Authors. Journal compilation © 2010 Ecological Society of Australia
Volume 35, Issue 7, pages 818–824, November 2010
How to Cite
ARAYA, Y. N., SILVERTOWN, J., GOWING, D. J., MCCONWAY, K., LINDER, P. and MIDGLEY, G. (2010), Variation in δ13C among species and sexes in the family Restionaceae along a fine-scale hydrological gradient. Austral Ecology, 35: 818–824. doi: 10.1111/j.1442-9993.2009.02089.x
- Issue published online: 28 OCT 2010
- Article first published online: 28 OCT 2010
- Accepted for publication October 2009.
- cape floristic region;
- carbon isotope discrimination;
- hydrological gradient;
- plant gender;
- soil water regime trade-off;
- water-use efficiency
Consistent, repeatable segregation of plant species along hydrological gradients is an established phenomenon that must in some way reflect a trade-off between plants' abilities to tolerate the opposing constraints of drought and waterlogging. In C3 species tissue carbon isotope discrimination (δ13C) is known to vary sensitively in response to stomatal behaviour, reflecting stomatal limitation of photosynthesis during the period of active growth. However, this has not been studied at fine-spatial scale in natural communities. We tested how δ13C varied between species and sexes of individuals in the family Restionaceae growing along a monitored hydrological gradient. Twenty Restionaceae species were investigated using species-level phylogeny at two sites in the Cape Floristic Region, a biodiversity hotspot. A spatial overlap analysis showed the Restionaceae species segregated significantly (P < 0.001) at both sites. Moreover, there were significant differences in δ13C values among the Restionaceae species (P < 0.001) and between male and female individuals of each species (P < 0.01). However, after accounting for phylogeny, species δ13C values did not show any significant correlation with the hydrological gradient. We suggest that some other variable (e.g. plant phenology) could be responsible for masking a simple response to water availability.