The Effects of Native Shrub, Fencing, and Acorn Size on the Emergence of Contrasting Co-Occurring Oak in Mediterranean Grazed Areas

Research Highlights: The regeneration of Quercus species is usually very difficult in many oak woodlands transformed by livestock farming. Some studies have reported that shrubs can facilitate regeneration. However, the strength interaction may vary depending on, among other factors, shrub and stress tolerance species. Moreover, further are necessary to clarify relative importance two facilitation mechanisms same community. Background Objectives: Cytisus multiflorus (L’Her.) Sweet a predominant Mediterranean grazed open-oak-woodlands found central west Iberian Peninsula (bioclimatic limit) present with pyrenaica Willd ilex subsp. ballota Samp trees. Thus, we assessed effect these native acorn size, excluding large herbivores, on seedling emergence contrasting co-occurring under bioclimatic limit. Materials Methods: A manipulative field experiment was carried out considering four treatments as combination (shrub/no-shrub) fence (fenced/open) factors. total twenty plots, five replicates for each treatment were available. In plot, 20 acorns sown: 10 (5 small 5 large) Acorn recorded during first years following sowing. Results: Seedling took place mostly spring year after presence main significant factor incremented both Q. pyrenaica. depended considered, improving only negative detected but all treatments, emerged more than Conclusions: C. had clear facilitative pyrenaica, which much greater physical size herbivores had. As such, this key role areas. Furthermore, areas contact between marcescent sclerophyllous species, currently emerges This could be indicative shift towards xeric climatic conditions, lead change dominant tree future. modulated effects herbivores.