An idealized model for tree–grass coexistence in savannas: the role of life stage structure and fire disturbances
Article first published online: 28 OCT 2009
© 2009 The Authors. Journal compilation © 2009 British Ecological Society
Journal of Ecology
Volume 98, Issue 1, pages 74–80, January 2010
How to Cite
Baudena, M., D’Andrea, F. and Provenzale, A. (2010), An idealized model for tree–grass coexistence in savannas: the role of life stage structure and fire disturbances. Journal of Ecology, 98: 74–80. doi: 10.1111/j.1365-2745.2009.01588.x
- Issue published online: 11 DEC 2009
- Article first published online: 28 OCT 2009
- Received 4 May 2009; accepted 11 September 2009 Handling Editor: Jonathan Newman
- demographic structure;
- multiple stable states;
- stable and unstable species coexistence;
- stochastic disturbance;
- tree seedlings
1. We discuss a simple implicit-space model for the competition of trees and grasses in an idealized savanna environment. The model represents patch occupancy dynamics within the habitat and introduces life stage structure in the tree population, namely adults and seedlings. A tree can be out-competed by grasses only as long as it is a seedling.
2. The model is able to predict grassland, forest, savanna and bistability between forest and grassland, depending on the different characteristics of the ecosystem, represented by the model’s parameters.
3. The inclusion of stochastic fire disturbances significantly widens the parameter range where coexistence of trees and grasses is found. At the same time, grass-fire feedback can induce bistability between forest and grassland.
4. Synthesis. These results suggest that tree–grass coexistence in savannas can be either deterministically stable or stabilized by random disturbances, depending on prevailing environmental conditions and on the types of plant species present in the ecosystem.