Data from: Large frugivores matter more on an island: insights from island-mainland comparison of plant-frugivore communities

Endozoochory, a mutualistic interaction between plants and frugivores, is
one of the key processes responsible for maintenance of tropical
biodiversity. Islands, which have a smaller subset of plants and
frugivores when compared with mainland communities, offer an interesting
setting to understand the organization of plant-frugivore communities
vis-a-vis the mainland sites.  We examined the
relative influence of functional traits and phylogenetic relationships on
the plant-seed disperser interactions on an island and a mainland site.
The island site allowed us to investigate the organization of the
plant-seed disperser community in the natural absence of key frugivore
groups (bulbuls and barbets) of Asian tropics. The endemic
Narcondam Hornbill, was the most abundant frugivore on the island and
played a central role in the community. Species strength of frugivores (a
measure of relevance of frugivores for plants) was positively associated
with their abundance. Among plants, figs had the highest species strength
and played a central role in the community. Island-mainland comparison
revealed that the island plant-seed disperser community was more
asymmetric, connected and nested as compared to the mainland community.
Neither phylogenetic relationships or functional traits (after controlling
for phylogenetic relationships) were able to explain the patterns of
interactions between plants and frugivores on the island or the mainland
pointing towards the diffused nature of plant-frugivore interactions. The
diffused nature is a likely consequence of plasticity in foraging behavior
and trait convergence that contribute to governing the interactions
between plants and frugivores. This is one of the few studies to compare
the plant-seed disperser communities between a tropical island and
mainland and demonstrates key role played by a point-endemic frugivore in
seed dispersal on island.