The ecological value of Eryngium horridum in maintaining biodiversity in subtropical grasslands
Article first published online: 4 MAY 2009
© 2009 The Authors. Journal compilation © 2009 Ecological Society of Australia
Volume 34, Issue 5, pages 558–566, August 2009
How to Cite
FIDELIS, A., OVERBECK, G. E., PILLAR, V. D. and PFADENHAUER, J. (2009), The ecological value of Eryngium horridum in maintaining biodiversity in subtropical grasslands. Austral Ecology, 34: 558–566. doi: 10.1111/j.1442-9993.2009.01959.x
- Issue published online: 21 JUL 2009
- Article first published online: 4 MAY 2009
- Accepted for publication August 2008.
- biotic refuge;
- nurse plant;
- plant community
The role of facilitation in the structuring of plant communities has been often demonstrated in environments under high abiotic stress, especially in semi-arid and arid ecosystems and high elevations. Few studies, however, analysed facilitation in systems that are highly productive and rich in species, which are thought to be theoretically unlikely to demonstrate strong effects of facilitation. Here, we investigate the importance of Eryngium horridum, a rosette species, on the maintenance of plant diversity in subtropical grasslands in southern Brazil. We evaluated facilitation in areas under two different types of management: abandonment and grazing. Plots were established in areas with and without individuals of E. horridum and all species were identified and had their cover estimated. The Relative Neighbour Effect index was calculated in order to verify the presence of competition or facilitation. Our results indicated facilitation in both abandoned and in grazed grasslands, but apparently through different mechanisms. In the first case, the plant's architecture opens the canopy and allows more light to reach small forbs in the grass matrix. In the second case, E. horridum appears to protect more palatable species from herbivores. Otherwise considered an obnoxious species, E. horridum plays an important ecological role in subtropical grasslands in southern Brazil by facilitating other species and consequently, increasing local richness. Areas with this rosette species are important sources of diaspores, which are able to colonize new open sites and thus, maintain biodiversity.