Kosciusko National Park encompasses 673,542 hectares and is New South Wales' largest national park. The park contains outstanding natural and cultural features and is the source of the Snowy, Murray and Murrumbidgee rivers.
Extensive scientific research has occurred and continues to occur into the impact of introduced animals on the park, including pigs, deer and horses. While pigs and deer are known to cause impacts, scientific evidence indicates that wild horses also cause soil compaction and loss through erosion. They damage waterways and reduce water quality through riverbank collapse, compaction and channelling. Wild horses also reduce native vegetation coverage, contributing to loss of habitat for native species such as the broad-toothed rat, and placing further pressure on a range of threatened plants and animals. As such, 'Habitat degradation and loss by Feral Horses (brumbies, wild horses), Equus caballus' is a key threatening process listed in the NSW Biodiversity Conservation Act 2016. There are known to be at least 19,000 horses in the park (based on 2019 estimates).
All other introduced animals in the park, including pigs, foxes, deer, cats, rabbits and dogs, are being controlled by separate strategic and integrated pest control programs.
Wild horses are also a risk to public safety. Multiple vehicle collisions with wild horses have been recorded on the Snowy Mountains Highway. As a result, many horses have been killed and private vehicles damaged. Wild horses are also a risk to visitor safety in park campgrounds and may cause damage to private vehicles and camping equipment. This safety issue has been exacerbated by some campground visitors feeding horses, which further encourages horses into these areas.