Wild boar (Sus scrofa) as a driving force of vegetation changes in an urban mediterranean forest affecting species richness and biodiversity within a protected area

Abstract

The Insugherata Protected Area is a remnant urban forest located on the outskirt of the city of Rome; it is rich in native plant species and biodiversity and provides several ecosystem services. Since 2004 the environmental pressure on this fragmented forest ecosystem strongly increased due to the ingression of wild boar (Sus scrofa) which currently has a permanent population in the Reserve and is considered a “pest” impacting several habitats. In 1994, before wild boars ingression, a vegetation survey was undertaken in the Reserve and 20 years later, in 2015, they were repeated in the same plots, being the presence of wild boars the only known change in pressures occurred over time. The comparison of the flora assemblage between the two periods showed a decrease in number of plant species (-15.8%), particularly in the understory. Geophyte was the life form more affected with a decrease in number of species (-22.6%) and coverage (-29.7%) from 1994 to 2015. Also species indicator of environment quality (i.e., orchids) and of biogeographical plant communities disappeared overtime, together with locally rare species, indicating a severe impact on biodiversity not only limited to plant richness. The consistent vegetation changes occurred between the two periods were also computed with a plant community turnover of approximately 40% (Sørensen index of dissimilarity) and one-way analysis of similarities p<0.05 (ANOSIM). Management of the wild boar population is needed in order to favor habitat conservation and reduce local biodiversity loss, as stated in the designation legislative framework of the Reserve.

Keywords

• Vegetation remnants
• Urban biodiversity
• Urban forest
• Wildlife pressure