Post‐dispersal seed removal in four Mediterranean oaks: species and microhabitat selection differ depending on large herbivore activity

Abstract

Quercus forest regeneration is limited by different factors, post‐dispersal predation being one of the most critical stages. We analysed seed removal of four coexisting Quercus species (Q. ilex, Q. suber, Q. faginea and Q. pyrenaica) in a Mediterranean forest located in Southern Spain. Marked and weighed acorns from each of the species were placed in experimental units with or without exclusion of large herbivores and in two microhabitat types (Q. ilex shade or open). Acorn removal was monitored for 120 days in order to test the effect of exclusion of large herbivore and microhabitat type on seed removal rates and species selection. Interestingly, the results of microhabitat and species selection differed depending on the presence of large herbivores. Removal was faster in sites without exclusion, where most seeds (≈85%) disappeared during the first 9 days. In these sites, no differences in seed removal were found between different microhabitats, but seeds of two species, those with higher seed mass (Q. suber and Q. pyrenaica) were most preferred. However, under exclusion of large herbivores, seed removal was affected by the microhabitat, this being greater in Q. ilex shaded microhabitats, which showed a higher structural diversity. Also, species selection was completely different under exclusion of large herbivores, and seeds of Q. ilex and Q. faginea were removed faster. These results highlight the importance of large herbivore activity on seed removal and its effect on microhabitat and species selection. Therefore, specific selection by seed consumers may modify seedling recruitment and may have an important influence on the relative abundance of coexisting Quercus species.

Bringing the Natives Back: Identifying and Alleviating Establishment Limitations of Native Hardwood Species in a Conifer Plantation

“…In addition, it has been reported that differences among seeds caused by seed nutrient content, physical and chemical defense mechanisms (e.g., shell hardness, presence of secondary metabolites, etc.) affect the preference of seed feeders [30]. However, our initial hypothesis that germinated seeds would be less favorable for seed consumers was rejected, as no significant differences on seed predation rates between fresh and germinated seeds were detected in the long term (more than two months after direct sowing).…”

‘Climatic factors control rodent seed predation in Pinus pinea L. stands in Central Spain’

“…Gómez et al 2003;González-Rodríguez and Villar 2012). These traits are often associated with animal activity, either seed predation or dispersal (Sork 1993).…”

Dispersal and hoarding of sympatric forest seeds by rodents in a temperate forest from northern China

“…However, sympatric seeds may differ notably in palatability and nutrition value (Vander Wall 1990). To survive and reproduce, seed-eating animals had developed numerous adaptations in treating and consuming various sympatric seeds , González-Rodríguez & Villar 2012, Yang et al 2012.…”

“…Studies carried out so far on seed selection and dispersal of sympatric seeds by rodents are limited , González-Rodríguez & Villar 2012, Yang et al 2012, Rusch et al 2013) and far from fully depicting the wide variation in the hoarding behavior of rodents in different geographical areas. Hull thickness has been reported to significantly affect seed dispersal , while other investigations have obtained conflicting result (Yang et al 2012).…”

“…In the forest, plants disclose seed features to attract possible dispersers but avoiding over-predation at the same time; correspondingly, rodents discriminate seeds depending on their palatability, nutrition and physical characteristics (Vander Wall 1990, Muñoz et al 2012, Rusch et al 2013). For instance, small rodents feed mainly on small-sized seeds, while larger rodents consume seeds of various sizes (Vieira et al 2003).Studies carried out so far on seed selection and dispersal of sympatric seeds by rodents are limited , González-Rodríguez & Villar 2012, Yang et al 2012, Rusch et al 2013) and far from fully depicting the wide variation in the hoarding behavior of rodents in different geographical areas. Hull thickness has been reported to significantly affect seed dispersal , while other investigations have obtained conflicting result (Yang et al 2012).…”