Dispersal spectra, diaspore size and the importance of endozoochory in the equatorial Andean montane forests

Endozoochory was the main dispersal syndrome of the woody plant species evaluated. Associated diaspore traits, such as single seeded, small size and black or purple fruits, were the most common, probably because they are attractive to bird seed dispersers. The most common fruit types in cloud forests were berries, drupes and dehiscent capsules. On the other hand, the percentage of endozoochorous species in cloud forests was correlated to the mean annual temperature, rather than annual rainfall. We also found a distinct increase in anemochory with elevation. Furthermore, and as predicted, we found that the mean diaspore length of endozoochorous assemblages decreased with altitude. Our results suggest that in the equatorial montane forests, endozoochory is the most common dispersal syndrome although environmental stress in high elevation zones promotes an increase in the prevalence of anemochorous species. Anemochorous species produce dry fruits and small diaspores, probably favored at high elevations due to the low temperatures and nutrients availability and the high costs involved in the production of suitable pulp for animal dispersers.