Frugivory and seed dispersal in the Cerrado: Network structure and defaunation effects

Seed dispersal is a fundamental process that is highly threatened by the
rapid decline of large-bodied frugivores worldwide. The Brazilian Cerrado,
the largest savanna in the world, represents an ideal site for
investigating seed dispersal because of its biodiversity, environmental
challenges, and knowledge shortfalls. We performed a Systematic Literature
Review to analyze the seed dispersal network in the Cerrado and the
potential impacts of the defaunation of large-bodied frugivores on it. We
considered network metrics, calculated the defaunation index of the
frugivore assemblage, and compared traits among different fruit-sized
plants and their respective dispersers in the network. We retrieved 1,565
interactions involving 193 plant species and 270 animal species. Results
show that the Cerrado seed dispersal network is slightly nested and
considerably modular, dominated by small to medium-sized generalist
species, such as passerines, marsupials, and mesocarnivores. Nonetheless,
large-bodied frugivores like the lowland tapir have a key role in the
network due to their great foraging and network integration capacity. The
Cerrado frugivore assemblage is moderately defaunated, with possible
effects in its interactions with large-fruited plants.  The
Cerrado’s defaunation and functional loss of large vertebrates deserve
urgent attention to further understand the impacts on seed dispersal
mechanisms and ecosystem functioning.