Seed Dispersal Syndromes in the Rain Forest of Chiloe: Evidence for the Importance of Biotic Dispersal in a Temperate Rain Forest

Abstract

TFhe dispersal syndromes of seventy-two species from the temperate rain forest of Chilo6 (42030' S) were analysed and compared with data for other temperate for- ests in New Zealand and New Jersey (eastern U.S.A.), and for dry, moist and wet neotropical forests. In Chiloe, ornithochory was the predominant dispersal syndrome for species of each growth form (70% of trees, 59% of shrubs, and 72% of vines and epiphytes). Only among the emergent trees anemochory was the most frequent syndrome. The overall distrubutions of dispersal syndromes were similar in Chiloe and New Zealand. In these forests, ornithochory was found in c. 70% and anemochory in 20-25% of the species. Mammalochory was rare in Chilo6 and absent in New Zealand. In contrast, mammalochory was more pro- minent in all neotropical sites (22-34% of the species). In proportion, avian-disseminated propagules were more represented among forest taxa in Chilo6 and New Zealand (67-70% of the species) than in the neotropics (35-53%). Deciduous forests of New Jersey, U.S.A., showed similar proportions (-33%) of mammalochory, anemochory and ornithochory, having a distribution of syndromes that resembles that of dry neotropical forests. The contrasting array of dispersal syndromes in North and South temperate forests might be related to (1) the different ancestral pools for temperate forest taxa in each hemisphere, (2) the different relative isolati-on (past and present) of the areas compared, and (3) the different abundances of fruit-eating mammal species in each area. In all forests compared, with the exception of Chilo6, shrubs had the highest frequency of fleshy-fruited species. The higher incidence of ornithochory among shrubs seems to be related to the grea- ter bird activity in forest clearings and margins, which would act to reinforce the association of ornithochorous shrubs with such habitats. Mutual dependence between fleshy-fruited plants and fruit-eating animals may be well developed in the temperate forests of Chilo6.