Estimating wild boar density and rooting activity in a Mediterranean protected area

The mitigation of ecological/economic impacts of wild boar Sus scrofa is one of the most challenging issues in wildlife management worldwide. Monitoring population density and impact of wild boar is crucial to plan appropriate management actions to reduce its density, environmental impact and epidemiological risk, as well as to evaluate control effectiveness. In 2018–2019, we used plot-based faeces counts, coupled with specific estimates of daily defecation rates, to estimate wild boar density and rooting activity in natural/semi-natural habitats, in a Mediterranean protected area. Daily defecation rate was 6.7 faeces/individual, much lower than that of ruminants. We obtained estimates of 70.0–70.5 faeces/km2, corresponding to wild boar densities of c. 10.5 individuals/km2 (relative standard error: 18%) in both years. Low daily defecation rates and skewed distribution frequencies of wild boar faeces should be considered to plan surveys with an adequate sampling design and intensity. Faeces abundance and rooting activity peaked in ecotones, i.e. open areas at the interface of wood patches, whereas they did not differ between other habitat types, suggesting a fine-scale concordance between the two indicators. Long-term monitoring is needed to assess relationships between indicators of impact and abundance at a broad scale. Our work shows how to undertake simultaneously wild boar density estimates and impact assessment in natural environments, which is particularly important for protected areas and/or habitats of conservation concern across the globally distributed Mediterranean biome.