MONTREAL -- Two environmental groups say they're ready to take the federal government to court if it fails to protect a population of tiny brown frogs they say are threatened by a road expansion project south of Montreal.

The two Quebec-based groups are calling on Ottawa to issue an emergency order to protect a western chorus frog population they say is threatened by the City of Longueuil's plan to expand a major boulevard through one of the amphibian's few remaining habitats in the province.

Genevieve Paul, executive director of the Centre quebecois du droit de l'environnement, said federal Environment Minister Jonathan Wilkinson has an obligation to recommend an order is issued "to intervene in this situation to protect the critical habitat of the frog." Paul said the groups are prepared to take the matter to Federal Court if Wilkinson doesn't recommend such an order by Wednesday.

In an emailed statement late Friday, a spokeswoman for Wilkinson's office did not confirm whether the recommendation would be made.

"The Minister's decision will be informed by the best available information, including scientific evidence, that is gathered and provided by Environment and Climate Change Canada," wrote Joanna Sivasankaran, who added that the office recognized the need for "timely decisions."

The western chorus frog breeds in small, often temporary wetlands that are increasingly threatened by agriculture and urban sprawl. Adults grow to a maximum length of less than four centimetres. While the species' numbers are secure globally, the population in Canada's Great Lakes/St. Lawrence--Canadian Shield region has been listed as threatened since 2010, and current estimates suggest up to 90 per cent of its habitat has been lost in recent decades.

The federal government issued an emergency order in 2016 to protect a western chorus frog population threatened by a housing development in La Prairie, Que., another Montreal suburb not far from Longueuil. The developer sued and the case went to the Supreme Court of Canada, which eventually declined to hear the landowner's appeal.

Paul said the groups have no choice but to appeal to Ottawa because the Quebec government has failed in its duty to protect the frog, due she said both to a lack of will and a regulatory framework that limits interventions on private land.

Alain Branchaud, the head of the conservation group SNAP Quebec, called the Coalition Avenir Quebec government an "authorization regime" that rarely refuses to approve a project. Instead, he said, it will ask for "mitigation measures" that are ultimately inadequate.

The City of Longueuil says on its website that the 300-metre road expansion has been requested by citizens for years and has received the go-ahead from provincial authorities. It says it is taking biodiversity, including the frogs, into account.

It notes the project includes a large concrete tunnel under the new road aimed at allowing the frogs to pass safely between the two parts of their bisected habitat.

Branchaud says the wildlife passage is insufficient because it doesn't stop the destruction of the ponds the frogs need to breed. He said the construction itself will damage water levels and vegetation, and that the city is likely to eventually build housing along the side of the new boulevard.

"The essence of its habitat will be completely destroyed, so we'll pass a tunnel from one side where there are no more frogs to the other side of the boulevard where there won't be any more frogs," he said.

Branchaud said he's hopeful the federal government will step forward on its own, but if not, the groups will go to court to protect the amphibians.

Despite the previous high-profile legal battle over the frogs, he says it's wrong to think they are having widespread impact on construction south of Montreal.

He also says that the idea of finding a balance between frogs and developers is ludicrous when the frogs have already lost 90 per cent of their habitat and continue to lose about seven per cent of what remains each year.

"Nature has already made enormous compromises," he said. "Maybe it's our turn to make some."

-- This report by The Canadian Press was first published Oct. 16, 2021.