Wild Boars!

Photo by Ashley Barbagello Veiwed on 08/04/2014

Feral pigs (Sus scrofa) are descendants of various sub-species of the domestic pig derived from stock that were let loose or escaped. They occupy a vast range of vegetation from subalpine grasslands to monsoonal floodplains. Their largest concentrations are on the larger drainage basins, and swamp areas of the coast and inland. (Bengsen, et al, 2014)

Feral Pigs, are an ecological, economic and social pest. Their impact on the environment is extensive.  By grazing and rooting they damage pastures, digging up large areas of native vegetation and spread weeds, cause soil erosion, degrade waterholes and wetlands. This digging behaviour can severely disrupt the composition of the soils microorganisms and consequently nutrient cycling. This can also disrupt the regeneration of plants, change the composition of the plant community and allow water erosion to occur in drainage areas where the soil is disrupted. (Bengsen et al 2014)

  Environmental damage is largely through modification of natural habitat, but predation and competition with native animals has also been reported. Feral pigs can also carry disease and parasites that affect stock and people. Through predation of stock, consumption and damage of crops feral pigs cost the agricultural industry alone an estimated $100 million per annum (Lopez et al, 2014).

Photo by Ashley Barbagello. Viewed 08/04/2014

Several methods are practiced to control feral pigs. One effective way to keep pigs out is exclusion fencing; fencing off small high value areas such as cropping or lambing paddocks. However this method is highly costly on time and maintenance and ineffective on large scale areas as well as only relocates the problem rather than contribute to control it.

 Other methods include government trapping programs and recreational hunting via shooting or dogging. It is estimated that hunters kill 15-20% of the feral pig population in accessible areas.  Currently, the most cost effective and efficient control is the use of aerial baiting with 1080 (sodium monofluroacetate) (Barrious-Garcia, Ballari, 2012).  The effectiveness of the baits depend on a few variables as not all pigs within an area will take the baits depending on alternative food availability, pig density within the area and density of baits. One study found that success rates vary form 58% to 99.4% (Hone, 2002). None of these methods have been proven to be stand alone solutions for the complete eradication of the feral pig.

References:

Bengsen A.J, Gentle M.N, Mitchel, J.L, Pearson H.E, Saunders G.R 2014, Impacts and management of wild pigs Sus scrofa, In Australia, Mammal Review, Vol.44, no.2, pp.135-147.

Barrious-Garcia M.N, Ballar, S.A 2012, Impact of wild boar (Sus scrofa) on its introduced and native range: a review, Biological Invasion, vol.14, no.11, pp.2283-2300.

Hone, J 2002, Feral Pigs in Namadgi National Park, Australia; Dynamics, impacts and management, Biological Conservation, Vol. 105, no. 2, pp.231-242.

Lopez J, Hurwood D, Dryde B, Fuller S 2010, Feral Pig Populations are structured at fine spatial scales in Tropical Queensland, Australia, National Parks, vol.9, no. 3.