Written by: Kayla Berger, Ashtyn Dokuchie, Rhiannon Lace, Reanna Moore
History: Wild boar are native to Western Europe and Northern Africa, although they have long since spread further north and east through Europe, Asia, the Middle-East, Oceania and parts of Australia (Oliver & Leus, 2008). First introduced to North America in the 14th century, they have since disseminated into at least 38 states and 3 Canadian provinces. (McClure et al., 2015). While previously their numbers had fluctuated and density remained relatively low, wild boar were re-introduced in the United States in 1912, which marked the beginning of their relative proliferation (Pastick, 2014).
Prior to the 2013 study completed by Brook and van Beest, there was very little research on the distribution, feeding habits, risks related to wild boars or strategies to control populations in Canada. In western Canada, wild boar can now be considered an invasive species due to their dramatic increase in abundance and widespread expansion throughout the Canadian prairies (Brook & van Beest 2013). Further east, there is much information lacking about their distribution and population density, in Ontario and Eastern Canada.
Within Ontario, there have been sightings and instances of escapes from farms, but never a free-ranging population comparable to those in the prairies and southern United States (Wild Boar Canada, 2017) (Brook, Beest & Floris, 2013). According to local paper the Ottawa Citizen, in 2008, sixteen boar broke free of a farm south-east of Ottawa. However, in the 5 years following this occurrence, only six wild boar sightings were reported to the MNRF in Ontario (Bostelaar, 2014).
Ecological connection: The success of the wild boar relies on its ability to be resilient. This is important for the species because it has a very high mortality rate due to hunting, disease and environmental factors. It is able to be on the least concern species list because of its high reproduction rate. The species is a K strategist with some R strategist components. Since the female live in groups called sounders, (Breeding of wild hogs. 2001) the young have a better chance of survival since the females tend to be very protective. This species has a low sexual maturity age which leads to a high reproduction rate, which is needed when the rate of survival as an adult is low.
Wild Boar are very good at simple migration because of their ability to run at very high speeds which is used to get away from predators or escape when feeling threatened. While traveling, if they come to a water ways the species tend to be very good swimmers. The wild boar species is very widely dispersed only being limited by environmental factors as well as snow and lowered temperatures. The barriers that stop them during dispersal is man made objects such as fencing and urban development.
The young male wild boar will choose to travel after being kicked out of the sounder and chased away by other males because of the competition for a mate. Other reasons for wild boar to disperse from one area to another is because of environmental conditions such as floods, or droughts. One of the big contributors to the dispersal of the wild boar species is hunting. (Keuling et al, 2016) This causes wild boars to leave areas of habitat by chasing them out and having then feel threatened. The only problem about chasing them out of an area is that the species will just develop in a new area, causing the same problems.
Critical Assessment of Management Options: Wild Boars have already established on a global scale so the effort to remove them all is almost impossible. A more strategic way in reducing numbers is through attainable management opportunities. The main goal when trying to manage an invasive species is to help native species to become more resilient and resistant to the spread of the non native species. In order to start managing wild boar, more significant research and monitoring has to take place immediately. If these actions are completed beforehand, there are three primary options that are considered and assessed based on costs, benefits, and additional factors. The options include; doing nothing, poisoning, fencing or hunting (trapping/shooting). Each option is addressed and discussed in the following paragraphs.Doing nothing for a management strategy is always an option. In certain situations, taking action can lead to no difference in a population you are trying to control. Sometimes it can actually lead to a loss of money spent and time put into the management process. In this case, doing nothing would dramatically increase the spread of populations across all landscapes. The cost to restore agricultural areas (crops) and replace livestock constantly would be extremely high (Ferreira E, 2016). With increasing populations, wild boar could easily overpopulate towns and cities and become even more destructive than they already are. They would also outcompete almost all species of wildlife with the exception of some predators. Food sources would be scarce and ecosystems would fall apart. Taking absolutely no action to manage this invasive species would create significant environmental issues.
Bostelaar, Robert. (2014). Shoot to kill: wild boars are back in Eastern Ontario. Ottawa Citizen. Retrieved from http://ottawacitizen.com/news/local-news/shoot-to-kill-the-wild-boars-are-back-in-eastern-ontario
Brook[JF1] [V2] , Ryan K. & van Beest, Floris M. (2013). Distribution and risk perceptions of prairie boar. Wildlife Society Bulletin. DOI: 10.1002/wsb.424.
McClure, M. L, Burdett, C. L., Farnsworth, M. L., Lutman, M. W., Theobald, D. M., Riggs, P. D., Grear, D. A., Miller, R. S. (2015). Modeling and mapping the probability of occurrence of invasive wild pigs across the contiguous United States. Public Library of Science. http://dx.doi.org/10.1371/journal.pone.0133771
Oliver, W. & Leus, K. 2008. Sus scrofa. The IUCN Red List of Threatened Species 2008: e.T41775A10559847. http://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T41775A10559847.en.
Pastick, Jillian. (2014). The biology of native and invasive wild boar (Sus scrofa) and the effect it is having in its invasive range. Eukaryon, 8, 60-63. Retrieved from https://www.lakeforest.edu/live/news/1650-the-biology-of-native-and-invasive-wild-boar-sus
Wild Boar Canada. (2017). Wild boar sightings Canada. Retrieved from http://wildboarcanada.ca/#sthash.PNSIagrd.dpbs