Feral horses an ‘imminent threat’ that could cause extinction of several endangered Australian species, inquiry warned

Feral horses in the Australian alps pose an imminent threat to the Albanese government's zero extinctions target, a scientific committee that advises the government on endangered species has told a parliamentary inquiry.

The threatened species scientific committee (TSSC) says feral horses "may be the crucial factor that causes final extinction" of six critically endangered animals and at least two critically endangered plants.

The warning is contained in a submission to a Senate inquiry examining the damage feral horses are causing to sensitive alpine ecosystems.

"Feral horses in the alps therefore pose an imminent threat to the threatened species action plan's objective to prevent new extinctions of plants and animals," a single sentence written in bold states.

The Albanese government announced a target last year of zero new extinctions as part of a revamped threatened species strategy to address the decline of Australia's environment.

Feral horses are a major threat in the alpine wilderness of New South Wales, Victoria and the Australian Capital Territory, including in the Kosciuszko national park.

They threaten native plants and animals by grazing, trampling vegetation and habitat, and damaging waterways.

The TSSC submission says horses are a known threat to 12 animals - three frogs, four fish, four reptiles and one mammal - six of which are critically endangered.

For several species, a combination of threats has reduced them to a single population or a couple of very small populations confined to small areas, placing them at severe risk of extinction.

"[Horses] mess this habitat up in a way that the entire population is highly at risk unless we get serious," Prof Chris Johnson, a member of the TSSC and author of the submission said.

"We could be looking on the map at a hotspot of extinction that we will regret.

"We need urgent management action to stop that from happening."

The affected species include the critically endangered stocky galaxias, a fish that has an extremely restricted distribution due to the impacts of invasive trout. The submission notes the species is now restricted to a single small section of the headwaters of Tantangara Creek - an area where horses are abundant.

Three other types of critically endangered galaxias and the critically endangered southern and northern Corroboree frogs are also at risk.

Another species, the broad-toothed rat, which is listed as vulnerable, is being considered for an upgraded conservation status of endangered partly due to the effect of feral horses.

Surveys by state governments show feral horse numbers are increasing. The previous New South Wales government failed to meet a commitment to reduce horse numbers.

In a separate submission to the inquiry, the federal environment department wrote NSW was not on track to meet a target to reduce the number of horses in Kosciuszko national park to 3,000. It estimated about 4,000 horses a year would need to be removed to meet this target.

Modelling by the Invasive Species Council estimates a higher figure of 6,000 a year.

Advocacy manager Jack Gough said the council was calling on the Albanese government to develop national heritage management principles to require states and territories to "effectively and urgently remove feral horses from the Australian Alps".

"This assessment from the threatened species scientific committee is a stark warning to minister [Tanya] Plibersek and the Australian government," he said.

"In 2008, the then federal Labor government declared the Australian Alps to be a national heritage place to protect its unique plants and animals and pristine mountain streams.

"It is now incumbent upon minister Plibersek to take action to save our native alpine wildlife and stop their habitat being trashed and trampled by feral horses."

Plibersek said she supported humane culling of feral horses and the federal government was providing financial support to the states and the ACT to reduce horse populations in the Alps.

"I look forward to receiving the final report from the Senate inquiry to make sure the federal government is doing everything we can to protect this precious place and the animals that call it home," she said.

The new NSW environment minister, Penny Sharpe, said horses were causing significant damage to the Kosciuszko national park.

"I want to ensure the horse management plan is implemented as soon as possible," she said.