The impact of the common rabbit on cork oak regeneration in SW Spain

Seed predation has traditionally been considered as simply a progressive loss of seeds. However, partial consumption of tree seeds may actually assist regeneration. We quantified partial consumption of acorns by the common rabbit (Oryctolagus cuniculus) in a cork oak forest in southwest Spain (Do?ana Natural Park). To examine the effects of partial consumption on germination and seedling emergence, we simulated two different levels of acorn predation (30 and 50?% cotyledon loss, representing light and heavy partial consumption, respectively). One-third of the sampled acorns presented evidence of consumption but most of the damage caused by partial consumption did not affect the acorn embryo (damage was mainly to non-vital parts of the propagule). Partial consumption caused more rapid germination and emergence than that was observed in intact acorns, but germination and emergence rate was unaffected. Heavy consumption of the acorn caused differences in root and shoot biomass as a consequence of cotyledon loss. In this greenhouse study, partial consumption was non-lethal to the acorns, and cotyledon biomass loss did not decrease the probability of successful establishment. Partially consumed seeds can therefore contribute significantly to the natural regeneration of Quercus coccifera, although it would be beneficial to conduct long-term studies focusing on seed traits and animal behaviour under field conditions.