Part III: Conservation and Management348
by 250 per cent between 2003 and 2011 (Gren et al. 2016). In
southern Europe, wild boar causes a major conflict, being
responsible for up to 85 per cent of all accidents involving ani-
mals in some Mediterranean regions (Camps et al. 2012).
The increasing length of the transport network, together
with higher traffic volume and speed, are some factors associ-
ated with the phenomena. In addition, a correlation between
wild boar population density and wild boar traffic accidents has
been reported (Gren et al. 2016). The rising numbers of wild
boar throughout Europe (Massei et al. 2015) lead to expecta-
tions of a growing conflict caused by wild boar in transport net-
works. This is also a social and economic concern; an average
cost of a wild boar collision has been estimated as €2700–€9119
in different areas, and it is reported that wild boar cause three
times more injuries per collision than roe deer in Spain, prob-
ably due to its gregarious behaviour (Colino et al. 2012; Sáenz-
de-Santa-María & Tellería 2015).
Wild boar–vehicle collisions show marked temporal pat-
terns (Rosell et al. 2003; Langbein et al. 2011; Lagos et al. 2012)
with higher frequencies from October to January. These months
are in the main rut period and the hunting season, both causing
behavioural changes that have been associated with an increase
in ungulate–vehicle collisions (Groot Bruinderink & Hazebroek
1996a; Langbein et al. 2011). An hourly variation has also been
observed, with most accidents at dusk and in the early hours of
the night. This coincides with the start of the wild boar’s activity
period, and with high volumes of vehicles on the roads.
Accidents caused by wild boar and other ungulates are clus-
tered, and both landscape- and road-related variables influence
their frequency. Features such as traffic volume, road straight-
ness, vehicle speed, roadside vegetation or land cover may influ-
ence animal–vehicle collisions at different scales (Malo et al.
2004; Seiler 2004; Thurfjell et al. 2015). Other wild boar-specific
factors have been reported to influence the frequency of acci-
dents, including the presence of food attractors beside the roads,
such as maize crops or even garbage containers (Colino et al.
2012; Torrellas 2014). The growing habituation of wild boar to
humans allows the species to colonize flat cropland areas, peri-
urban and even urban sites, and is probably influencing the
growth of the conflict, as the road network is denser in these
areas than in forested mountain habitats.
Numerous measures could be applied to reduce the con-
flict. Proper fauna passages and fences adapted to wild boar,
which are either buried or reinforced at the base, provide effec-
tive solutions along highways (Iuell et al. 2003; Huijser & Mc
Gowen 2010). Nevertheless, most accidents occur on conven-
tional roads (Rosell et al. 2013) where other measures must be
applied, often with low or temporary effects, such as reinforced
signposting and use of deterrents. Appropriate roadside habi-
tat maintenance is also an important factor that could help to
reduce accidents along conventional roads.Synurbization of Wild Boar
In recent decades, Europe has experienced a parallel expansion
of both wild boar populations (Massei et al. 2015) and urbanised
areas (Piorr et al. 2011). In addition to land-use changes, urbani-
zation also implies changes in human views towards rural areas(Antrop 2004) and wildlife management. Consequently, hunt-
ing activity has declined in many European countries and is
currently insufficient in halting wild boar population growth
(Massei et al. 2015).
High abundance of wild boar is considered as an impor-
tant factor underlying the increased presence of this species in
numerous towns and cities of Europe and elsewhere (Licoppe
et al. 2014). However, it is important to understand that (peri-)
urban areas themselves can represent attractive habitat for this
species (Licoppe et al. 2014). For example, in Berlin, Börner et al.
(2013) reported that much higher densities of wild boar were
harvested in peri-urban hunting areas (9/km^2 ) in comparison
with outlying rural regions (2.5/km^2 ), and Cahill et al. (2012)
reported significantly higher body weights among habituated
wild boar from urban areas of Barcelona in comparison with
non-habituated boar from the nearby Collserola Mountains
Natural Park.
Novel urban habitats can also attract wild boar during peri-
ods of food scarcity or temperature extremes in natural systems
(Cahill et al. 2012; Podgórski et al. 2013). In such contexts, direct
and indirect feeding (garbage, leftover pet food, etc.) by peo-
ple are potent initial drivers of wild boar habituation to urban
areas and their eventual synurbization. Their social group struc-
ture and high reproductive rate also facilitate the rapid spread
of this process, thus inevitably leading to a variety of conflicts
with people (Licoppe et al. 2014). Among those reported, dam-
age to crops, golf courses, public and private gardens, etc., and
collisions with vehicles are most prominent. Given such close
proximity, concerns also exist regarding the possibility of direct
injuries to people and on the possible implications for zoonoses,
or other public health issues (Jansen et al. 2007; Licoppe et al.
2014). For example, antibiotic resistance has been reported in
urban wild boar (Navarro-Gonzalez et al. 2013).
Such issues pose a challenge to wildlife managers (Putman
et al. 2014) in urban settings where public attitudes towards
wild boar and possible control options are often ambiguous
(Kotulski & König 2008). Management of ungulates in urban
areas of European countries tends to be reactive, with measures
implemented only when conflicts are already manifest (Putman
et al. 2014). If possible, effective population control in the ex-
urban landscape might act as a preventive measure for limiting
wild boar abundance in peri-urban areas, but current hunting
trends indicate that this is unlikely to be a solution (Massei et al.
2015). Indeed, the absence of hunting in urban settings is con-
sidered to be an added incentive to their established presence
there (Licoppe et al. 2014). As for other urban ungulates, selec-
tive shooting at baited sites may prove more effective (Putman
et al. 2014) where traditional hunting battues are either ineffec-
tive or simply not practical.
However, the use of firearms is not always feasible or legal in
urban settings, and also lethal control methods often meet with
strong opposition from the public, at least during early stages if
damages are still not excessive. Although fertility control is fre-
quently propounded by detractors of culling, for a variety of rea-
sons it is currently unlikely to provide solutions beyond specific
local situations, such as those of closed populations where hunt-
ing is not an option (Massei et al. 2014). To increase consensus,.03312:55:50