Journal cover Journal topic
Web Ecology An open-access peer-reviewed journal
Web Ecol., 9, 30-43, 2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.
04 Jun 2009
Mediterranean-climate oak savannas: the interplay between abiotic environment and species interactions
T. Marañón1, F. I. Pugnaire2, and R. M. Callaway3 1IRNASE, CSIC, P.O. Box 1052, 41080 Sevilla, Spain
2Estación Experimental de Zonas Aridas, CSIC, General Segura 1, 04001 Almería, Spain
3Division of Biological Sciences, Univ. of Montana, Missoula, 59812, USA
Abstract. Mediterranean oak savannas cover about 4 million ha in California (northwest America) and 3 million ha in Spain and Portugal (southwest Europe), and are ecologically and socio-economically important systems. Here we review literature on the interactions between the two dominant elements of savannas – the oak overstorey, the herbaceous understorey, and the surrounding grassland matrix. We focus on the main ecological factors affecting the oak understorey environment: shade, soil moisture, soil nutrients, and animal-mediated effects. We then review the main features of the herbaceous community in the oak understorey, as compared to the adjacent open grassland, in terms of species composition, biomass, diversity, and soil seed bank. We examine processes associated with oak regeneration and growth, and their relationships with the herbaceous layer and other woody plants cover. Finally, we discuss the complex facilitative and interference interactions that occur in oak-grassland systems and review models proposed to explain the dynamics and coexistence of oak trees and herbaceous plants in savannas.

Citation: Marañón, T., Pugnaire, F. I., and Callaway, R. M.: Mediterranean-climate oak savannas: the interplay between abiotic environment and species interactions, Web Ecol., 9, 30-43,, 2009.
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