Nomenclature: Tutin et al. (1964-1993).
Indirect facilitation and competition in tree species colonization of sub-Mediterranean grasslands
Article first published online: 24 FEB 2009
2006 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 17, Issue 3, pages 379–388, June 2006
How to Cite
Kunstler, G., Curt, T., Bouchaud, M. and Lepart, J. (2006), Indirect facilitation and competition in tree species colonization of sub-Mediterranean grasslands. Journal of Vegetation Science, 17: 379–388. doi: 10.1111/j.1654-1103.2006.tb02458.x
- Issue published online: 24 FEB 2009
- Article first published online: 24 FEB 2009
- Received 13 October 2005; Accepted 28 March 2006
- Fagus sylvatica;
- Herb competition;
- Quercus pubescens;
- Root morphology
Questions: In the absence of herbivores, what is the importance of shrub facilitation for the colonization of grasslands by Fagus sylvatica and Quercus pubescens? Is there an indirect facilitative effect of shrubs on tree seedlings by limiting herb competition?
Location: Causse du Larzac, southern Massif Central, France. Methods: We conducted field experiments on the facilitative role of shrubs in seedling emergence and survival, in relation to potential negative effects of shading and the presence of herbs. The effects of shade and herbs on allocation and root morphology were analysed in a pot experiment.
According to these experiments, the establishment of both tree species was facilitated by shrubs, but the two species differed in the processes underlying this facilitation. Shade directly facilitates the emergence rate of both species. Shade also indirectly facilitates Fagus survival by limiting herb competition. No indirect facilitation of Quercus survival was detected. These differences reflect variation in the tolerance of herb competition by seedlings of the two species. The tolerance of herb competition by Quercus seedlings allows regeneration over a wide area under each shrub and some regeneration events in grasslands at low grazing intensity. In contrast, for Fagus, only a narrow area under each shrub is suitable; regeneration is zero in grassland. The high tolerance of herb competition by Quercus seedlings may result from the avoidance of root competition.
In grasslands with severe drought stress, and almost obligatory shrub facilitation for tree seedling regeneration, the tolerance of herb competition may alter the precise role of facilitation in the colonization process.