THE wild horse population in high country national parks has skyrocketed by 224 per cent in six years to nearly 7700, believed to be the highest number on record.
The surging total could actually be an underestimate for the high country, because surveys were not done in state forests, other land or in national park areas too steep for effective aerial observations but where horses are known to live.
Research also suggests that the population could keep rising sharply.
Researcher Michelle Dawson said the total could be 25 per cent higher than her figure, or nearly 9600, but it could also be 25 per cent lower.
A helicopter survey last April estimated the horse population to be 7679, up from the 2369 estimated in 2003, just after bushfires killed many horses.
In response to the survey, the Invasive Species Council said aerial shooting was urgently needed to stop feral horses destroying Kosciuszko National Park in New South Wales.
The survey was done in the NSW park and in Victoria's Alpine National Park. Its findings pose substantial challenges to public land managers in both states.
Dr Dawson, from the University of Wollongong, said that on current growth rates the population would exceed 13,800 by 2012, with a likelihood of increased environmental implications.
Other key findings include:
- The 21.65 per cent annual rise is close to the maximum believed possible in the alpine environment.
- The population has increased its distribution area since 2003 but has not spread into all habitable areas.
- The Victorian wild horse population was estimated at 3442.
- Horses could cope with a population density more than double the current figure (of 2.7 animals per square kilometre) before there are limitations on food availability.
When dealing with the horses, national park managers will have to assess two divergent viewpoints.
Some people know them as ''brumbies'', free-running horses that are a part of folklore thanks to poet Banjo Paterson. But park managers and many environmentalists know them as ''feral horses'', introduced animals that they say pose significant environmental threats.
A fact sheet produced by the parks services of Victoria, NSW and the ACT says many people are not familiar with the ''impacts and threats posed by these feral animals''.
The Victorian Brumby Association, a ''rescue'' group that finds homes for wild horses, said numbers needed to be managed ''responsibly'' and called for a trial of fertility control measures.
It also called for the establishment of brumby havens. ''Setting aside regions where brumbies can be humanely managed in the wild would ensure that future generations of Australians will have the opportunity to see brumbies running free,'' it said.
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