Feral pigs

Feral pigs can carry disease as well as destroy native fauna and flora Photo: Jim Mitchell

Overview

Domestic pigs were introduced as a food source about the time of European settlement. Throughout the 19th century, many were transported to other settlements and it was not long before feral populations of pigs became established.

Feral pigs have moved into Kakadu National Park and have also reached the coast of Arnhem Land. They cause considerable disturbance to the ground as they hunt for edible roots and invertebrates in the soil. This destructive 'rooting' behaviour is most intense when the ground is damp, and this is the time when seeds are germinating. The new seedlings are destroyed and so there is no regeneration of trees and shrubs to replace the old plants as they die. This effect of pigs on regeneration has been observed elsewhere in Australia, but has yet to be studied in detail in the far north.

Impact on environment

The effect on native vegetation is not the only problem with pigs, for these animals can carry exotic livestock diseases such as foot-and-mouth. If outbreaks occur, then pigs are likely to become infected and act as a reservoir for the virus, re-infecting cattle.

Pigs need a good water supply, so they tend to follow creek lines. During flooding they are able to get into new areas, and then they survive dry times by clustering around bores. In this way, they even make it into arid areas. For pastoralists, pigs are a worry mainly because of their disease-carrying potential, but also because they will sometimes prey on lambs and they can damage fences and bore drains.

In tourist areas, large pigs are also of concern because they can attack people and their digging has a noticeable visual impact.

Resource use

However, like other ferals, pigs can also be viewed as a resource. In bad times landholders may even survive because of sales of wild boar meat, much of which is exported.

To see a recent list of research findings on feral pigs click here .