Estimation of European wild boar relative abundance and aggregation: a novel method in epidemiological risk assessment

Abstract

SUMMARYWild boars are important disease reservoirs. It is well known that abundance estimates are needed in wildlife epidemiology, but the expense and effort required to obtain them is prohibitive. We evaluated a simple method based on the frequency of faecal droppings found on transects (FBII), and developed a spatial aggregation index, based on the runs test statistic. Estimates were compared with hunting data, and with porcine circovirus and Aujeszky's disease virus seroprevalences and Mycobacterium tuberculosis complex and Metastrongylus spp. prevalence. The FBII and the aggregation index were correlated with the hunting index, but both of the former estimates correlated better than the latter with the disease prevalences. Hence, at least in habitats with high wild boar densities, the FBII combined with the aggregation index constitutes a cheap and reliable alternative for wild boar abundance estimation that can be used for epidemiological risk assessment, even outside the hunting season and in areas with no available data on hunting activities.

Epidemiology of Mycobacterium Bovis Infection in Wild Boar (Sus Scrofa) From Portugal

“…Relative abundance indices for wild ungulates were computed using the method described by Acevedo et al (2007). One to three 4-km transects were walked in every study area, each divided into 50-m sections, determined with a pedometer.…”

Specificity and success of oral-bait delivery to Eurasian wild boar in Mediterranean woodland habitats

“…Briefly, each count consisted of n=40 transects of 100 m, divided into ten sectors of 10 m in length. Dropping frequency was defined as the average of the number of 10-m sectors with wild boar droppings in each transect of 100 m (DF=∑Di/n; where "D" is the number of dropping-positive sectors and ranges from zero to ten, and "n" is the number of 100-m transects, usually 40 per site; Acevedo et al 2007; see Table 1). Artificial selective feeders were evenly distributed across the sites 1, 2, and 3.…”

“…Site 4 had its own feeders since artificial feeding is routinely practiced in this estate. Feeder density ranged from 4.4 to 6.7 per 10 km 2 and from 19.3 to 98.0 per wild boar (Acevedo et al 2007; Table 1). Feeders were placed close to water holes (which is a limiting resource in summer in the study areas) or using already existing feeding points (site 4).…”

“…According with the size of each site our baiting densities varied from 6.41 at site 1 to 27.3 per km 2 at site 4 (in the case of the baits directed to wild boar piglets) whereas the baiting densities of baits directed to adult ones varied from 2.51 at site 1 to 9.09 per km 2 at site 4. Wild boar abundance indexes were estimated for each site as explained above (Acevedo et al 2007). Indexes of abundance of 0.17, 0.05, 0.02, and 0.28 were obtained for sites 1, 2, 3, and 4, respectively.…”

Monitoring wild pig populations: a review of methods

“…However, obtaining valid observations can be problematic. First, the tapetum lucidum of wild pigs are not reflective like other animals, making spotlight sightings more difficult (Acevedo et al 2007;Focardi et al 2001). The ability to observe wild pigs using a spotlight can vary greatly from observer to observer and also among different types of vegetation (e.g., Twigg et al 1998).…”