Feral pigs (Sus scrofa) are widespread in tropical northern Australia, and cause significant damage to the ecological and cultural values of wetlands by their rooting, pugging, and wallowing behaviour.
We investigated the impacts of feral pigs on the epigeic invertebrates of exposed wetland sediments using 48 pitfall trap samples collected from 21 sites in the Archer River catchment, Queensland, Australia. Feral pig damage was assessed visually in transects set along the margins of the wetlands. The prediction that the invertebrate assemblages would demonstrate reduced taxon richness and abundance and altered composition with increasing intensity of physical pig damage was tested.
Pig damage to exposed wetland sediments was found to be a stressor to epigeic invertebrates in this environment. Thirty epigeic invertebrate taxa showed a decrease in their occurrence, mean abundance, or both, at sites with high levels of pig damage relative to sites with low levels of pig damage. Certain families of spiders and beetles, snails, and freshwater crabs were amongst those taxa more prevalent when pig damage was low, whereas none of those taxa were more prevalent when pig damage was high.
The intensity of pig damage, as measured here, provides a useful monitoring indicator that could be applied to evaluate the effectiveness of pig control measures around wetlands.