Exotic Animals - Major Pests
Horses
Family: Equidae
Scientific names: Equus caballus
Background
Horses arrived on the First Fleet in 1788. In the following years, shipments of working farm horses were brought to Australia, however records indicate that these escaped or were abandoned in the early 1800s. This trend also increased as machines gradually replaced horses in a range of tasks, many horses were released to join the already established feral herds.
It is estimated that there are 300,000 feral horses throughout Australia, where they inhabit a range of habitats. On average, horses produce one foal every two years, leading to relatively rapid increases in the wild.
Impacts
Feral horses cause considerable damage to the natural environment, including: (a) increased erosion of soil and waterways, (b) increased spread of weeds, (c) trampling of native vegetation, (d) consumption of native seedlings leading to reduced biodiversity, (e) sedimentation of waterways and water bodies, (f) destruction of infrastructure, (g) competition with native species and domestic cattle for resources, and (h) spread of disease and parasites to domestic stock and native species. In addition, horses will travel up to 50 km for food and water, which means that they have the potential to cause extensive damage over a very wide range.
Management Practices
Horses can be managed using a number of techniques:
- Trapping or mustering wild horses so that they may be sold for meat or stock. This technique, while potentially effective is expensive and time consuming over large areas. In addition, in many cases, the numbers of animals that are required by the pet food trade are significantly less than the numbers that are required to be removed for environmental protection and sustainability.
- Aerial culling. This management practice requires extensive training of personnel because of the significant potential danger to humans as well as the animal welfare concerns. Aerial culling is one of the most effective, environmentally friendly and humane methods of removing large feral animals because it is target-specific and if implemented correctly will result in a rapid death, with very little suffering to the animal.
- On-ground culling. This technique is humane and relatively cost-effective compared with many of the other techniques, but is limited to accessible terrains.
- Fertility control is a non-lethal approach to feral horse management but it is currently of limited use. Fertility control techniques are difficult to administer to large numbers of feral horses and the treatment would need to be repeated often to be effective. There is very little evidence to suggest that this procedure would be effective of feasible for controlling large numbers of feral animals.
