The frugivores of the Anthropocene: Invasive species restores critical seed dispersal services in defaunated landscapes

Background/Question/Methods: Several invasive species are known to disperse native and exotic species in the areas where they have been introduced. Feral hog (Sus scrofa) is a generalist large-sized invasive mammal that dominate the biomass of vertebrates in many ecosystems, yet they have been poorly studied as potential seed dispersers. We tested if feral hogs have the potential to compensate the seed dispersal services of large native frugivores (tapirs and peccaries) in defaunated landscapes in the Atlantic forest, Brazil. Our study was based on stomach analyses of feral hogs (n=111), gut retention time (GRT) of captive animals, and seed removal experiments in 10 landscapes with distinct mammal assemblage.

Results/Conclusions: The diet of feral hogs consisted mainly on crops (sugar cane and corn; >80%), but we also found fruits from over 20 species and about 15,000 seeds in their stomachs. Feral hogs were able to ingest and disperse large seeds and had long gut retention times (up to 96 h), which increases seed dispersal distance. Simulations of seed dispersal kernel considering feral hog movement and GRT indicate that they are able to disperse many seeds among isolated forest fragments. The seed dispersal services provided by this invasive species may be crucial to maintain the gene flow of large seeded-plants in defaunated landscapes. However, feral hogs also provide many ecosystems disservices such as seedling trampling, and are the vector of several diseases.