Ecology, Conservation and Management of Wild Pigs and Peccaries

Part III: Conservation and Management

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Bevins et  al. 2014). A summary list of the primary types of

impacts that wild pigs cause in North America is provided in

Table 28.3. Most of these impacts are either directly or indirectly

the result of foraging activities by these animals.

Some positive effects have also been reported for wild pigs

(e.g. rooting activities aerating compacted forest floor soils, pro-

moting the propagation and regeneration of certain tree species,

increasing the growth in other tree species, and a prolific source

of meat for human consumption in rural areas). However, in

general, the negative impacts greatly outweigh the positive ones

(Mayer & Brisbin 1995, 2009).

The total comprehensive cost of wild pig damages through-

out North America has not been estimated to date. However,

various limited damage estimates have been reported. Pimentel

et al. (2005), using a general cost of $200 per wild pig for an esti-

mated national population of 4 million of these animals in the

USA, calculated a national estimate of $800 million for ‘envi-

ronmental and crop damage’ done annually. Pimentel (2007)

later increased the per pig cost to $300 and the population size

to 5 million animals, giving an annual estimate of $1.5 billion

for ‘crop damage and control costs’ in the USA. Mayer and

Johns (2007) estimated an annual nationwide estimate for wild

pig–vehicle collisions at $36 million. Damage estimates have

been compiled for parts or all of a few US states. For example,

Higginbotham et al. (2008) reported > $52 million in ‘damage

to Texas agriculture’ for seven of the eight ecological regions in

Table 28.3 Summary of the types of damage done by invasive wild pigs (Sus scrofa) in North America.

Type of damage Extent of

occurrence

Impacted

environment

Details of impacts

Natural Human

Rooting Widespread Direct Direct Destabilization of surface soils; erosion; sedimentation; degraded

water quality in aquatic habitats; lawn/sod damage; habitat

alteration; impacts to subsurface cultural/archaeological artefacts

and resources; impacts to soil chemistry/nutrient cycling; severely

rooted areas in croplands can cause damage to or impair agricultural

and farm equipment and machinery being operated there

Agricultural depredation Widespread – Direct Direct feeding and related trampling and rooting of a variety of

commercial crops (e.g. grains, vegetables, fruits and other crops)

Forestry/timber depredation Widespread Direct Direct Depredation of planted pine and hardwood seedlings; chewing on

lateral roots of mature pines; girdling trees through rubbing; damage

to bark through scent marking with tusk glands

Disease transmission Widespread Direct Direct Serve as disease reservoirs/vectors that can impact wild/domestic

animals and humans; major threat to livestock industry; primarily

Brucellosis and Pseudorabies Virus in North America; impacts to

potable drinking water sources

Depredation of native flora Widespread Direct – Forage on many types of vegetation; impacts vary by species; has

involved protected floral species

Predation of native fauna Scattered Direct Indirect Predators of invertebrate and vertebrate fauna (including wild game

species); prey on eggs through adults of ground-nesting game birds;

prey on eggs and hatchlings of sea turtles and crocodilians

Predation of domestic

livestock

Scattered – Direct Predators of domestic livestock; includes killing and eating juvenile

and adult goats, sheep, cattle and fowl

Competition with native

game species

Scattered Direct Indirect Compete with native game species for forage resources; primarily

based on dietary overlap; mast crop is the primary concern; spatially

displace white-tailed deer and collared peccaries

Competition with domestic

livestock

Scattered – Direct Compete with livestock for forage resources; similar to competition

with native game species, based on dietary overlap; includes both

feed and pasturage; will spatially displace some livestock from

feeding areas

Vehicle collisions Scattered – Direct Recent increase in these accidents; can be very serious; human

fatalities from such accidents increasing; involves 0.5–5.0 percent of

a wild pig population annually

Attacks on humans Rare – Direct Attacks on humans do occur; rare; potentially very serious

consequences; both hunting and non-hunting circumstances;

attacks in urban areas increasing

Property Damage Scattered – Direct Cause a variety of damage to property; frequent impacts to fences;

can variously include damage to lawns; in-ground irrigation and

sprinkling systems; scientific field instruments, etc.

Contaminate uptake Localized – Direct Potential vectors for introduction of contaminants (e.g. radionuclides,

metals, organochlorine pesticides and polychlorinated biphenyls)

into the human food chain; incidental ingestion of these contami-

nants during rooting

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