Phenology, abundance and consumers of figs ( Ficus spp.) in a tropical cloud forest: evaluation of a potential keystone resource

Fig trees (Ficus spp) produce fruit year-round and figs are consumed by a large proportion of frugivores throughout the tropics. Figs are potential keystone resources that sustain frugivore communities during periods of scarcity, but studies have produced contradictory results. Over 1 y we monitored the phenology of 206 trees of five Ficus species in a Colombian cloud forest, to test whether figs produced fruit during periods of low overall fruit availability. We also measured fig tree densities in 18 0.5-ha plots and made 190 h of observations at 24 trees of three species to determine whether figs were abundant and consumed by a large proportion of the local frugivores. The five species produced fruit year-round but fig availability varied monthly by orders of magnitude. Fig trees reached comparatively high densities of 1–5 trees ha−1 and were consumed by 36 bird species (60% of the local frugivore assemblage) and three mammal species. However, there was no season of fruit scarcity and figs represented on average 1.5% of the monthly fruit biomass. Figs in this Andean forest are part of a broad array of fruiting species and at least during our study did not seem to constitute a keystone resource.