Is the wild pig the real “big bad wolf”? Negative effects of wild pig on Atlantic Forest mammals

Abstract

The wild pig (Sus scrofa) is an invasive species that negatively impacts new areas into which it is introduced. In this study, we evaluated the effects of wild pig presence on the estimated occupancy and detection probabilities of native mammals in the Brazilian Atlantic Forest. We used camera traps at 100 different points for 8 days (800 trap-days) to collect data and two-species conditional occupancy models to estimate the probability of occupancy (ψ) and the probability of detection (p) of mammal species. We detected a total of 23 native mammal species and two non-native mammal species [wild pig and European hare (Lepus europaeus)] and generated 21 models to evaluate the effects of wild pig occupancy on the European hare and the following 13 native mammals: Cerdocyon thous, Pseudalopex gymnocercus, Hydrochoerus hydrochaeris, Mazama americana, Mazama gouazoubira, Mazama nana, Dasyprocta aguti, Dasypus novemcinctus, Leopardus wiedii, Puma yagouaroundi, Didelphis albiventris, Conepatus chinga, and Procyon cancrivorus. Overall, the presence of wild pig had a range of negative effects on the occupancy and detection of the other mammals, which were less likely to occupy areas that were occupied by wild pig. In addition, we observed lower occurrence and richness of native mammal species in sampling points where wild pig were present compared with locations where wild pig were not present. These results highlight the importance of wild pig management and control for the conservation of native mammals in the Atlantic Forest, a region that is already threatened by a high degree of fragmentation.