Wild boar impact on forest regeneration in the northern Apennines (Italy) Paolo Bongi a,⇑ , Marcello Tomaselli b , Alessandro Petraglia b , Davide Tintori b , Michele Carbognani b a ATC MS13, L.go Bonfigli 3/5, I-54011 Aulla (Massa-Carrara), Italy b University of Parma, Department of Chemistry, Life Sciences and Environmental Sustainability, Parco Area delle Scienze 11/A, I-43124 Parma, Italy article info Article history: Received 28 November 2016 Received in revised form 9 February 2017 Accepted 11 February 2017 Keywords: Exclosure method Feral pig Fruit selection Rooting Seedling survival Tree seedlings Ungulates abstract The foraging activities of wild boar (Sus scrofa L.) have been suggested to impact biodiversity and ecolog- ical processes in a wide array of ecosystems. Data indicate that wild boar affects forest vegetation by feeding on above- and belowground plant parts, as well as by soil disturbance causing plant mortality and influencing seedling recruitment. In this paper, we investigated wild boar impacts on forest regen- eration within three different types of mixed deciduous woodlands, respectively dominated by chestnut (Castanea sativa), Turkey oak (Quercus cerris) and beech (Fagus sylvatica) occurring in the northern Apennines (Italy), a mountain area where wild boar numbers have increased rapidly in recent decades. The goal of our study was to present a robust procedure targeted towards estimating wild boar impact on fruits predation and seedling survival of tree species. We evaluated the impact comparing wild boar excluding plots with completely access free ones. Differently from the majority of other experiments, we used replicated exclosure plots (by means of an electro-welded iron grid) excluding wild boars with- out excluding all other large ungulates such as deer and native small vertebrates. This method, tested with camera trapping surveys, was effective in reducing time spent by wild boar on experimental plots in comparison with other animals. Nevertheless, the number of fruit was similar in the exclosure plots and completely access free plots. Our study demonstrated, however, that wild boar feeds preferentially with the bigger fruits that are visually more attractive and have higher energetic potentialities too. The proportion of seedlings survived at the end of the period studied was significantly higher in wild boar excluding plots compared to those completely access free. Moreover, the dominant species were not equally influenced by the exclosure method, with chestnut and beech more markedly affected with respect to Turkey oak. Finally, the seedling survival of subordinate tree species, compared to the one of dominant plants, was reduced by the activity of wild boars in all the woodlands studied. This impact could lead to reduced tree species richness of the woodlands under study with negative effects on the biodiversity of plants and animals within these ecosystems. Ó 2017 Elsevier B.V. All rights reserved. 1. Introduction Forest regeneration process is conditioned by several climatic, environmental and biotic factors. In particular, it is subject to the impact of ungulate herbivores, which could compromise the sur- vival of tree seedlings. Indeed, the effects of ungulate browsing on tree regeneration (e.g. Ammer, 1996; Jorritsma et al., 1999; Reimoser, 2003) are well known, with particular focus on deer browsing (Cutini et al., 2011; Pépin et al., 2006; Ward et al., 2008). The forest management programs should accordingly take into account the impact of ungulate herbivores, especially in mountain habitats (Côté et al., 2004; Reimoser, 2003; Vavra et al., 2007). However, ungulate communities are not composed exclusively by deer and bovid species, but also by wild boar (Sus scrofa L.). This species is now one of the globally most widely distributed invasive ungulates, and may have pervasive impacts on ecosystem pro- cesses, biodiversity and regeneration in temperate forests and many other ecosystems (Barrios-Garcia and Ballari, 2012; Bevins et al., 2014; Campbell and Long, 2009). In its native range in main- land Europe, wild boar numbers have increased rapidly in recent decades (Massei and Genov, 2004); moreover, the species is expanding northwards beyond its preferred habitat of broadleaved forests (Haaverstad et al., 2014). An increasing occurrence pattern http://dx.doi.org/10.1016/j.foreco.2017.02.028 0378-1127/Ó 2017 Elsevier B.V. All rights reserved. ⇑ Corresponding author at: piazza Don Venturini 3, I-54011 Aulla (Massa- Carrara), Italy. E-mail addresses: bongip73@yahoo.it (P. Bongi), marcello.tomaselli@unipr.it (M. Tomaselli), alessandro.petraglia@unipr.it (A. Petraglia), davide.tint@live.com (D. Tintori), michele.carbognani@unipr.it (M. Carbognani). Forest Ecology and Management 391 (2017) 230–238 Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco