Habitat loss and extirpation of large frugivores in tropical forests jeopardize the regeneration of hundreds of tree species. Atlantic Forest in Brazil used to be one of the largest rainforests in the world, a biodiversity hotspot, but nowadays only 12% of its original forest cover left stand, 50% of which are small fragments with high isolation between fragments. Even worse, most of left remnants are completely defaunated of large frugivores. Because large-seeded trees in Atlantic forest stock more carbon than small-seeded trees, the extinction of large frugivores may have consequences for important ecosystem services. Defaunation and habitat loss became major threats to Atlantic forest, and while attempts to revert this scenario are far from become reality, an unforeseen ecological analogue is resurrecting seed dispersal process. Feral hogs (wild pigs Sus scrofa) recently introduced in Brazilian ecosystems are rapidly expanding its range, occupying fragmented and defaunated landscapes. They are known worldwide by their voracious appetite, but also by their role as large-bodied frugivores. We used naturalistic and experimental observations and modelling to assess the consequences of feral hog’s invasion in Atlantic forest.
Results/Conclusions
By evaluating stomach contents and fecal samples, we found that fruits are the third most important item in feral hog’s diet. They are swallowing and dispersing intact seeds of a variety of species. Germination tests comparing defecated seeds with manually pulped seeds resulted in positive or neutral effect on seed germination due to gut passage. Combining gut retention time, body mass and movement allometry, we could model seed dispersal kernels, and feral pigs figured as long distance seed dispersal agents. We also employed camera traps in 10 different study sites of Atlantic forest remnants covering a gradient of defaunation, to experimentally evaluate rates of fruit removal at regional scale. We recorded 20 frugivores species removing fruits. The main contribution was given by agoutis Dasyprocta spp. removing 40% of fruits, followed by opossums Didelphis spp. (removing 17%), white-lipped peccary Tayassu pecari (16%) and feral hogs (10%). Among all frugivores recorded removing fruits, feral hogs are the only species that can promote connectivity and gene flux of plants through seeds between fragments. Despite it is considered one of 100’s worst invasive species in the world, their role as large-bodied frugivore is unique in reestablishing seed dispersal process in defaunated Atlantic forest.