Relative effects on human and feral hog disturbance on a wet forest in Hawaii

Abstract

The effects of 20 months of intensive disturbance by humans, as well as the presence of feral hogs Sus scrofa, was measured on vegetation. Both forms of disturbance have been thought severely to affect Hawaiian rain forests by reduction of plant cover and allowing the proliferation of exotic plants. Despite much human use throughout the study area, the only significant (P ≤ 0·05) effects were within 2 m of a trail. This disturbance was limited to vegetation < 10 cm in height. No change in canopy cover or in incidence of exotic plants was noted. Feral hog usage was approximately three times higher in the study area than outside, and caused a great deal of damage to the vegetation. The direct impact of humans is relatively minor, being restricted to < 5% of the area. The greater frequency of hogs in the study area could have an undetermined but possibly serious effect on the vegetation.