By Blake Foden
Brumbies in Kosciuszko National Park are trampling the habitat of a critically endangered fish and could soon wipe out the entire species, a University of Canberra researcher has warned.
The NSW government's controversial Kosciuszko Wild Horse Heritage Bill 2018 was passed late on Wednesday, despite widespread criticism from scientists around Australia and the world.
The legislation bans the lethal culling of brumbies in the national park because of their cultural significance, reversing the NSW government's plan to cull an estimated 90 per cent of wild horses in the park over 20 years, leaving just 600.
University of Canberra associate professor Dr Mark Lintermans has blasted the decision, saying it "flew in the face of science" and warning that it could spell the end for the stocky galaxias freshwater fish.
A stocky galaxias freshwater fish, which is part of a critically endangered population in Kosciuszko National Park.Credit: University of Canberra
The species, which was listed as critically endangered by the NSW government in 2016, is now confined to a single population in a three-kilometre section of Tantangara Creek.
“Brumbies are very abundant in the small catchment where the stocky galaxias live, and they are eroding stream banks," Dr Lintermans said.
Fine sediment in a horse crossing of Tantangara Creek, in Kosciuszko National Park.Credit: University of Canberra
"This fish is one of the most threatened freshwater fish in the country, there's no doubt about that, and I would not be surprised if it's not there in 20 or 25 years' time."
Dr Linterman said brumbies were degrading Tantangara Creek in about 12 locations where the fish lived, with the sediment left behind smothering the galaxias’ breeding and feeding habitats.
Brumbies in the high country near Kiandra, in Kosciuszko National Park.Credit: Karleen Minney
He estimated that there may still be 2000 or 3000 stocky galaxias in the creek, but warned it would not take much to wipe them out completely.
“Stocky galaxias need clean rocky-bottomed streams to breed," Dr Lintermans said.
The edge of a stream in Kosciuszko National Park that University of Canberra researchers say has been degraded by brumbies.Credit: University of Canberra
"They attach their eggs to the underside of rocks, with the eggs taking 30-40 days to hatch in the cold upland environment.
“Sediment smothers spawning sites and kills eggs, as well as filling up important pools where the fish live.”
Dr Lintermans said stocky galaxias had been pushed into their small remaining habitat by the predatory brown and rainbow trout, which were responsible for a 98 per cent reduction in the distribution of stocky galaxias.
"Now the brumbies are impacting on them in their last stronghold," he said.
Brumbies have run wild in Kosciuszko National Park for more than 150 years.Credit: Karleen Minney
"I understand the iconic status of the horses, but really, they're just a feral animal up there where they shouldn't be, just like rabbits, pigs or foxes."
NSW Deputy Premier John Barilaro, whose electorate of Monaro includes Kosciuszko National Park, introduced the legislation banning lethal culling of brumbies in the park.
In response to questions about whether the bill provided adequate protection for the park's flora and fauna, including stocky galaxias, he said the bill sought to "strike the best balance between the heritage status of brumbies and the protection of Kosciuszko National Park".
He stressed that while brumbies would be protected from lethal culling, the legislation did provide for their removal from the park.
"This legislation is not the [wild horse] management plan, it’s the framework within which a management plan will be developed, in consultation with key stakeholders and experts," Mr Barilaro said in an emailed statement.
"This plan will set out how and where sustainable wild horse populations will be maintained and the actions to be put in place to protect the environment."
The legislation's passage through the NSW Parliament has angered several scientific and environmental groups, which had fiercely lobbied against it because of concerns about the brumbies' environmental impact.
The bill has also prompted the resignation of Professor David Watson from the NSW Threatened Species Scientific Committee, which advises NSW Environment Minister Gabrielle Upton.
"Clearly, our advice has been ignored and I can no longer continue to justify committing my time, energy and professional insight," Professor Watson wrote in his letter of resignation, which he sent to Ms Upton on Thursday morning.
"... The wilful disregard that you and your government colleagues have for science diminishes our collective future, relegating our precious national parks and pricless environment to political play things."
NSW Labor has promised to repeal the legislation if elected next year.