Published by Associazione Teriologica Italiana Volume 25 (1): 31–38, 2014 Hystrix, the Italian Journal of Mammalogy Available online at: http://www.italian-journal-of-mammalogy.it/article/view/9314/pdf doi:10.4404/hystrix-25.1-9314 Research Article Monitoring protocols for the evaluation of the impact of wild boar (Sus scrofa) rooting on plants and animals in forest ecosystems Stefano Fagiani a,∗ , Daniele Fipaldini a , Luca Santarelli a , Sabina Burrascano b , Eva Del Vico b , Eleonora Giarrizzo b , Maurizio Mei a , Augusto Vigna Taglianti a , Luigi Boitani a , Alessio Mortelliti c a Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, Viale dell’Università 32, 00185 Rome, Italy b Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy c Fenner School of Environmental and Society, Australian Research Council Centre for Environmental Decisions, National Environmental Research Program, The Australian National University, Camberra ACT 0200, Australia Keywords: ground invertebrates small mammals understorey vascular plants power analysis effect size Article history: Received: 06 November 2013 Accepted: 08 February 2014 Acknowledgements The research has been supported by grants from the National Park of Circeo and from the Regional Agency for the Parks - ARP Lazio. Thanks to Giuliano Tallone, Dario Capizzi and Andrea Monaco for helping to realize this project. The authors are also grateful to the staff of the Corpo Forestale dello Stato who gave the logistical assistance in the field work. Additional support was provided by the Interuniversity Research Center “Biodiversity, Plant Sociology and Landscape Ecology”. Thanks to Elisabetta Del Bello for language revision. Abstract The management of wild boar (Sus scrofa) is an issue of increasing global conservation concern. Statistically robust monitoring protocols, allowing the detection of biologically relevant changes in biodiversity indices due to wild boar activities, are crucial tools for the management of wild boar populations. The goal of our study was to present a robust procedure targeted towards elaborating monitoring protocols for the evaluation of the impact of wild boar rooting on forest plants and animals. We compared two pairs of macro-areas characterized by contrasting levels of rooting activity. We then evaluated the effect of rooting on several parameters of four forest communities: understorey vascular plants, ground invertebrates, Carabid beetles and small mammals. We found that the even- ness of the Carabid community was significantly higher in high-rooting macro-areas. Moreover, the diversity and evenness indices of understorey vascular plants were higher in high-rooting macro- areas, while the abundance of the Etruscan shrew (Suncus etruscus) was higher in the low-rooting macro-areas, although these differences were only marginally significant. The results of the remain- ing tests were all non-significant. However, confidence intervals of measured effect sizes always included biologically relevant effects; therefore, these results should be considered inconclusive. The magnitude of the effect we detected on several biodiversity indices was considerably small (probably due to a certain degree of rooting affecting currently and in the past all the macro-areas), therefore high sampling effort should be required to detect such subtle differences. Researchers and practitioners should carefully consider the complexity of monitoring the impact of wild boar and the choice of the parameters to investigate since our study clearly shows that monitoring some biodiversity indices requires a substantial investment of sampling effort and a well-structured a priori-planning phase. Failing to do so will inevitably lead to a waste of resources and /or wrong management decisions. Introduction European populations of the wild boar (Sus scrofa) are increasing in local abundance and geographic range across Europe (Massei and Genov, 2004; Apollonio et al., 2010). In large part this is due to the life-history traits of the species (an habitat generalist with omnivorous diet and high fertility; Bieber and Ruf 2005; Gethöffer et al. 2007) com- bined with the lack of predators in the more anthropized environments (Saez-Royuela and Telleria, 1986) and the reintroduction for hunting purposes (Long, 2003; Rollins et al., 2007). Given the high ecological and socio-economic impacts of the species (Pimentel et al., 2000), wild boar management is a growing concern for public administrations and conservation agencies (Bieber and Ruf, 2005; Monaco et al., 2010). The activities of the wild boar, such as nesting, feeding and root- ing, have been suggested to impact a wide array of taxa and ecolo- gical processes such as the chemical properties of soil (Mohr et al., 2005; Risch et al., 2010; Wirthner et al., 2011), the forest understorey and grassland diversity and dynamics (Howe et al., 1981; Ickes et al., 2001, 2005; Siemann et al., 2009; Bueno, 2011; Bueno et al., 2011), the plant community structure (Cushman et al., 2004), seedling survival, abundance and distribution (Sweitzer and Van Vuren, 2002; Gómez * Corresponding author Email address: s.fagiani@campus.unimib.it (Stefano Fagiani) and Hódar, 2008), acquatic and terrestrial invertebrates communities (Vtorov, 1993; Baubet et al., 2003; Kaller and Kelso, 2006; Giménez- Anaya et al., 2008), the abundance of saprophageous and predatory soil arthropods (Mohr et al., 2005), ground-nesting birds (Rollins and Carroll, 2001; Schaefer, 2004), herpetofauna (Wilcox and Van Vuren, 2009; Jolley et al., 2010) and small mammals (Singer et al., 1984; Fo- cardi et al., 2000). In addition to the above mentioned negative impacts some positive effects have been detected on tree species regeneration (Lacki and Lan- cia, 1986; Ickes et al., 2001, 2005; Siemann et al., 2009) and on the species richness of forest understorey (Welander, 1995; Milton et al., 1997). Some authors hypothesized that some of the abovementioned positive effects may be related to the aeration of the soil and the in- creasing mobilization of nutrients due to rooting (Singer et al., 1984; Lacki and Lancia, 1986). Barrios-Garcia and Ballari (2012) suggested that idiosyncratic results on rooting effects could be due to the species range (native or introduced) where studies were carried out. Although much important work on the impact of wild boar activities has been carried out, to date most of existing knowledge comes from observation-correlation research. Only a few studies were specifically designed to compare biodiversity patterns in areas with contrasting im- pacts of wild boar activities. In fact, the ideal study should compare areas with similar habitat types where the species is present and areas where it is not, e.g. fenced vs. unfenced areas. To our knowledge, Hystrix, the Italian Journal of Mammalogy ISSN 1825-5272 4th June 2014 ©cbe2014 Associazione Teriologica Italiana doi:10.4404/hystrix-25.1-9314