The Morrison government has pledged $50m to help rescue and protect wildlife affected by the bushfire crisis, with a promise of more to come, as environment groups warn some species may have already been driven to extinction.

Government ministers said the commitment, drawn from the government’s $2bn bushfire recovery fund, was a downpayment to be spent immediately on priorities in burned areas and planning for longer-term protection and restoration of habitat.

Conservation groups wrote to the federal environment minister, Sussan Ley, and her state counterparts on Thursday expressing concern for at least 13 animal species, and urging the government to use a review of national environment laws launched last year to boost wildlife protection.

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The letter by five groups echoes earlier warnings by scientists in saying the fires may have triggered extinction events for some threatened species.

It sets out a recommended emergency wildlife recovery plan, including that scientists and conservationists be sent into the field immediately to identify and help at-risk animal populations as part of a coordinated national response.

The federal government said its immediate priorities would be caring for and rehabilitating injured wildlife, securing viable populations of threatened species, controlling feral predators and other pests that are a major threat to vulnerable species after fires, scientifically mapping the damage and working with landowners to protect unburned areas that act as “arks” in which plants and animals could recover.

The treasurer, Josh Frydenberg, said $25m would go to an emergency intervention fund that would be spent based on advice from a panel of experts led by the threatened species commissioner, Sally Box. He said the other $25m would be available to support wildlife rescue at a local level by zoos, natural resource management groups, Greening Australia and Conservation Volunteers Australia.

“This initial investment of $50 million into the protection and restoration of our wildlife and habitat is a critical step in creating a viable future for the animals that have survived,” Frydenberg said.

Ley said it was too early to know the severity of the fire damage, but it was clear it was an ecological tragedy. She said the recovery effort would require collaboration between governments, environment groups, scientists, farmers, communities, business, philanthropists and industry.

She said koala populations had taken an “extraordinary hit” to an extent that it may be necessary to see whether the species should be considered endangered in parts of the country. Koalas are currently listed as vulnerable.

Quick guide Climate change and bushfires Show Hide Does climate change cause bushfires? The link between rising greenhouse gas emissions and increased bushfire risk is complex but, according to major science agencies, clear. Climate change does not create bushfires, but it can and does make them worse. A number of factors contribute to bushfire risk, including temperature, fuel load, dryness, wind speed and humidity. What is the evidence on rising temperatures? The Bureau of Meteorology and the CSIRO say Australia has warmed by 1C since 1910 and temperatures will increase in the future. The Intergovernmental Panel on Climate Change says it is extremely likely increased atmospheric concentrations of greenhouse gases since the mid-20th century is the main reason it is getting hotter. The Bushfire and Natural Hazards research centre says the variability of normal events sits on top of that. Warmer weather increases the number of days each year on which there is high or extreme bushfire risk. What other effects do carbon emissions have? Dry fuel load - the amount of forest and scrub available to burn - has been linked to rising emissions. Under the right conditions, carbon dioxide acts as a kind of fertiliser that increases plant growth. So is climate change making everything dryer? Dryness is more complicated. Complex computer models have not found a consistent climate change signal linked to rising CO2 in the decline in rain that has produced the current eastern Australian drought. But higher temperatures accelerate evaporation. They also extend the growing season for vegetation in many regions, leading to greater transpiration (the process by which water is drawn from the soil and evaporated from plant leaves and flowers). The result is that soils, vegetation and the air may be drier than they would have been with the same amount of rainfall in the past. What do recent weather patterns show? The year coming into the 2019-20 summer has been unusually warm and dry for large parts of Australia. Above average temperatures now occur most years and 2019 has been the fifth driest start to the year on record, and the driest since 1970. Is arson a factor in this year's extreme bushfires? Not a significant one. Two pieces of disinformation, that an “arson emergency”, rather than climate change, is behind the bushfires, and that “greenies” are preventing firefighters from reducing fuel loads in the Australian bush have spread across social media. They have found their way into major news outlets, the mouths of government MPs, and across the globe to Donald Trump Jr and prominent right-wing conspiracy theorists. NSW’s Rural Fire Service has said the major cause of ignition during the crisis has been dry lightning. Victoria police say they do not believe arson had a role in any of the destructive fires this summer. The RFS has also contradicted claims that environmentalists have been holding up hazard reduction work. Photograph: Regi Varghese/AAP

Ecologist Chris Dickman, from the University of Sydney, estimates more than one billion animals have been killed in bushfires that have burned more than 10.7m hectares (26m acres) across the country. According to a Victorian government report leaked to the Age, fires in that state have burned 31% of rainforests, 24% of wet or damp forests and 34% of lowland forests. Among the worst affected species was the eastern ground parrot, which was believed to have lost all its Victorian habitat.

The letter from conservation groups raises specific concerns for species that have had all or key parts of their entire habitat burned. It lists 13 animals, including three critically endangered species: the southern corroboree frog in the alps, the regent honeyeater in the Blue Mountains and the western ground parrot on Cape Arid in Western Australia.

Others listed are the greater glider and long-footed potoroo in East Gippsland, the Kangaroo Island dunnart and glossy black cockatoo on Kangaroo Island, the brush-tailed rock wallaby, Hastings River mouse and eastern bristlebird in northern New South Wales, the quokka in Western Australia’s Stirling Ranges, the Blue Mountains water skink and the koala in areas across NSW.

The letter says it is likely other species will have been catastrophically affected, particularly poorly studied amphibian, reptile and invertebrate species.

“The devastating impact of these bushfires highlights the need for an effective and responsive national environmental law framework to safeguard and recover our imperilled wildlife and heritage places,” the letter says.

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“The current EPBC [Environment Protection and Biodiversity Conservation] Act review provides an opportunity to enact strong protections for critical habitats and climate refugia for species and ecosystems.”

Environment groups welcomed the government’s $50m commitment on Monday as a good first step, but said more would be needed.

James Trezise, from the Australian Conservation Foundation, said safeguarding species into the future would require protection of critical habitats and funding for recovery actions as well as stronger national environmental laws.

Suzanne Milthorpe, from the Wilderness Society, said it was critical that state and federal governments overcame a “lack of cooperation and buck-passing that have characterised the last decade of environmental action in this country” and worked together.

Labor’s environment spokeswoman, Terri Butler, welcomed the funding, but said the government had been slow to act and had a woeful record on the environment, including cutting environment department funding by almost 40%.

Sarah Hanson-Young, from the Australian Greens, said $50m was nowhere near enough; that 10 times as much funding was required. “When Celeste Barber can raise as much money as the federal government has committed to this tragedy, it shows (its) heart’s not in it,” she said.

The letter from environment groups, including Birdlife Australia, WWF and Humane Society International, says the short-term response to the fires should include a rapid evaluation of damage to world heritage sites and Ramsar-listed wetlands. The Unesco world heritage centre expressed concern in November about bushfire damage to the Gondwana rainforests of northern NSW and southern Queensland.

It calls for the review of EPBC Act, led by the businessman Graeme Samuel, to consider the development and implementation of recovery and threat reduction plans for threatened species. Less than 40% of nationally listed threatened species have formal recovery plans.

Launching the review of EPBC Act last year, Ley stressed it would “tackle green tape” and reduce project approval delays.

Hundreds of scientists have called on the government to use the review to strengthen the law to help address a worsening extinction crisis.