Species traits and their non-additive interactions control the water economy of bryophyte cushions
Article first published online: 19 SEP 2011
© 2011 The Authors. Journal of Ecology © 2011 British Ecological Society
Journal of Ecology
Volume 100, Issue 1, pages 222–231, January 2012
How to Cite
Michel, P., Lee, W. G., During, H. J. and Cornelissen, J. H. C. (2012), Species traits and their non-additive interactions control the water economy of bryophyte cushions. Journal of Ecology, 100: 222–231. doi: 10.1111/j.1365-2745.2011.01898.x
- Issue published online: 13 DEC 2011
- Article first published online: 19 SEP 2011
- Received 12 April 2011; accepted 22 August 2011 andling Editor: Fernando Maestre
- community structure;
- ecosystem hydrology;
- non-additive effects;
- plant–plant interactions;
- species mixture;
- water retention
1. Ecological processes in mixed-species assemblages are not always an additive function of those in monocultures. In areas with high ground cover of bryophytes, renowned for their considerable water retention capacity, non-additive interactions in mixed-species cushions could play a key role in the ecosystem water economy.
2. We investigated mixture effects on external water loss in natural cushions with different species pairs of mosses and liverworts and the underlying mechanism of any non-additivity through shoot characteristics and canopy traits.
3. Species mixtures in bryophyte cushions had both additive and non-additive effects on the water economy, and these interactions were dependent on the composition of species assemblages and on plant tissue mass. Non-additivity of species mixtures was positive, resulting in the improvement of water retention.
4. Our results suggest advantages for bryophyte species to grow smaller and denser when in mixtures. They appear to alter the surface exchange area to converge in size with their neighbours, thus controlling boundary-layer properties and evaporation to reduce water loss.
5. Synthesis. A shift in bryophyte assemblages thus may influence ecohydrological processes of various ecosystems that cannot be simply predicted from the water economy of the component species when in monospecific cushions. In contrast to vascular plants, bryophytes do not compete for water but share it, and trait plasticity amongst bryophyte mixtures acts as a critical physical strategy in the community water economy.