Impact of the wild boar, Sus scrofa, on a fragment of Brazilian Atlantic Forest

Abstract

The wild boar (Sus scrofa Linnaeus, 1758) was introduced approximately 100 years ago into South America from Europe for commercial reasons but since then it became feral and has caused several environmental impacts. One of the areas invaded by wild boars in the southern Atlantic Forest biome is the Aracuri Ecological Station (EEA), state of Rio Grande do Sul, Brazil. The objective of this study was to estimate the impact of wild boars on the vegetation of the EEA, describing their preferred vegetation types and the area and biomass affected. We sampled 1,521 points in 10 phytophysiognomies throughout the reserve. Among these points, 246 (16.2%) had evidence of wild boars (impacted patches with uprooted vegetation and soil) in the forests, wetlands, and secondary vegetation phytophysiognomies. Areas with Baccharis sp. were not impacted. The impacted patches had an average size of 308 ± 54 m2, ranging from 0.1 to 5,670 m2 within and between phytophysiognomies, with the largest mean impacted area (781 m2) in the most conserved forest type. We estimated that boars uprooted 56,186 kg of dry biomass over all the points sampled, 94% of which in the forest environments and 82% in the two most conserved forest types only. These results allow us to conclude that wild boars prefer to forage in forest areas, disturbing the vegetation and the superficial soil layer. Wild boars demonstrated a high potential for producing a strong negative impact on plants and animals in the studied forest fragments, indicating that these processes require further studies.

Key words: invasive species, exotic fauna, environmental impact.