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

Abstract

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 postdispersal 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.