Journal of Vegetation Science 28 (2017) 1047–1056 Can native shrubs facilitate the early establishment of contrasted co-occurring oaks in Mediterranean grazed areas? A. Costa, S. Villa, P. Alonso, J.A. Garc  ıa-Rodr  ıguez, F.J. Mart  ın, C. Mart  ınez-Ruiz & B. Fern andez-Santos Keywords Abiotic stress; Cytisus multiflorus; Dehesa; Facilitation; Herbivory pressure; Quercus pyrenaica; Quercus ilex; Seedling growth; Seedling survival; Shrub cover Nomenclature Castroviejo et al. (1986–2012) Received 23 November 2016 Accepted 25 April 2017 Co-ordinating Editor: Beverly Collins Costa, A. (albacoslor@gmail.com) 1 , Villa, S. (svilla@usal.es) 1 , Alonso, P. (palrojo@usal.es) 2 , Garc  ıa-Rodr  ıguez, J.A. (jantecol@usal.es) 1 , Mart  ın, F.J. (jmv@usal.es) 3 , Mart  ınez-Ruiz, C. (caromar@agro.uva.es) 4,5 , Fern andez-Santos, B. (corresponding author, belenfs@usal.es) 1 1  Area de Ecolog  ıa, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain; 2  Area de Edafolog  ıa, Universidad de Salamanca, Campus Unamuno, 37007 Salamanca, Spain; 3 Departamento de Estad  ıstica, Universidad de Salamanca, Campus Unamuno, 37007 Salamanca, Spain; 4  Area de Ecolog  ıa, Escuela T ecnica Superior de Ingenier  ıas Agrarias, Universidad de Valladolid, Campus La Yutera, 34071 Palencia, Spain; 5 E.T.S.II.AA., Sustainable Forest Management Research Institute UVa-INIA, 34071 Palencia, Spain Abstract Questions: Can shrubs (Cytisus multiflorus) and large herbivore exclusion (fence) facilitate seedling survival and growth of marcescent and sclerophyllous oaks (Quercus pyrenaica vs Q. ilex subsp. ballota) under a bioclimatic limit in Mediterranean grazed areas? Location: Open oak woodlands, central-western Spain. Methods: A 2-yr field experiment was conducted by planting 200 seedlings of each Quercus species under four different treatments combining the influence of nurse shrubs and fencing on Quercus seedling survival and growth. Results: Cytisus multiflorus enhanced poor Quercus seedling survival found in the study area, at least during the first 2 yr after planting and particularly during the first dry season. The improvement in soil organic matter under the shrub canopy may have contributed to this positive effect, which was more pronounced on Q. pyrenaica seedlings. Seedling herbivory did not seem to be a limitation to sur- vival. Increased seedling growth in both species was also very low, and no growth was recorded 2 yr after planting without shrubs. The positive shrub effect on seedling growth, especially marked in fenced areas, was more impor- tant in Q. pyrenaica in the first growing period and in Q. ilex in the second; 2 yr after planting no difference in shrub effect on growth was found in either Quer- cus species. Seedling herbivory was a limitation to seedling growth in areas with- out shrubs, mainly in the case of Q. pyrenaica. Conclusions: In Mediterranean grazed areas with important summer drought and very sandy soil, shrubby C. multiflorus plants have a clear facilitative effect on seedlings of ecologically contrasted Quercus species. The facilitative effect was found in both marcescent and sclerophyllous oak seedlings, but to a different degree depending on the species considered and the variable measured (survival or growth). In terms of survival, the marcescent species was more favoured by shrub cover than the sclerophyllous one, and this effect was accentuated through time. However, in terms of growth, although Q. pyrenaica was initially more favoured by shrubs, differences between the two species were attenuated after 2 yr. Therefore, C. multiflorus can have a key role in restoration of these oak degraded environments. Introduction Many oak woodlands worldwide have been transformed by livestock farming, giving rise to savanna-like landscapes (McCreary 2004; Bergmeier et al. 2010) with a predomi- nant pasture matrix of isolated oak trees and shrubs, with more or less cover often depending on the stocking rate. These landscapes present high biological diversity associ- ated with the high structural diversity generated (D  ıaz et al. 1997; Rolo et al. 2013), and oak trees are essential for the maintenance of ecosystem services (Mara~ n on et al. 2009). However, these woodlands are suffering dieback of 1047 Journal of Vegetation Science Doi: 10.1111/jvs.12550 © 2017 International Association for Vegetation Science