Pairwise plant-frugivore interactions build up into mega-diverse networks involving dozens and even hundreds of interacting species. Every interaction mapped in the network has a functional value for the whole system, and the diversity of their functional roles generates extensive complexity for plant regeneration and animal population dynamics. Because seed dispersal (and their counterpart interaction, plant food provisioning) is serviced by multiple species, studies focusing on pairwise interactions in isolation will underestimate levels of biodiversity required to maintain multifunctional networks. Loss of biodiversity in these assemblages entails losses of key functional services, and some of these losses may remain cryptic, i.e., their consequences undetected well after the loss.
Results/Conclusions
I explore several recent study cases documenting the extinction of seed dispersal interactions, and the loss of associated services that may occur well before the partner species become extinct. Taking advantage of last-generation sequencing (DNA barcoding) it is now factible to identify species-specific contributions to the seed shadows and estimate both demographic and genetic influences derived from interactions. Most seed dispersal mutualisms show a high functional complementarity among frugivore species in terms of seed deposition at different habitats, perches and distance sectors, cross-habitat seed fluxes, dispersal distances and canopy-cover dependency. The full functionality of the seed dispersal mutualism relies in this complementarity across a high diversity of partners. Disruptions of these mutualisms driven by anthropogenic drivers may remain subtle and undetected despite being pervasive for ecosystem functioning.