Pre- and post-dispersal seed predation in a mediterranean-type climate montane sclerophyllous forest in central Chile

Most seed-predation studies have evaluated pre- or post-dispersal predation separately, in one or a few species. Assessments of the overall importance of pre- v. post-dispersal seed predation at the community level are generally lacking. Here, we quantify levels of pre and post-dispersal seed predation in >25 plant species in a mediterranean-type climate montane forest in central Chile in two periods of study (1995-1996 and 1997-1998). Almost all species analysed suffered at least some seed losses to pre-dispersal and/or post-dispersal seed predation. However, among species, magnitudes of both pre- and post-dispersal seed predation proved highly variable, ranging between 0 and 100% and exceeding 50% in five and nine species, respectively. High inter-annual variability in both pre- and post-dispersal seed predation, at both the species and overall community levels, was observed, with only a small number of species suffering large losses during both periods of study. At the overall community level, percentage seed losses to pre-dispersal predation were not significantly different from those experienced in the post-dispersal phase. Rodents were the most important seed removers in seven species. However, the three groups of granivores analysed (rodents, birds and insects) were similar in their importance as post-dispersal predators in most plant species. Groups of species suffering similar levels of seed losses to pre- or post-dispersal predators did not share any particular seed characteristics, suggesting that differences in the seed traits studied seem to be relatively unimportant in determining variation in seed predation.