Imagine Ontario without a Canadian icon — the maple leaf.

That could become a reality if the provincial government doesn't put together a new plan to deal with significant threats to biodiversity, Ontario's environment watchdog warned Tuesday.

"We could lose sugar maple trees from southern Ontario," environmental commissioner Gord Miller said after releasing a new report. "We could lose black spruce in northern Ontario. We already have a major crisis in our fisheries in the Great Lakes. These are real — real problems."

Gord Miller, Environmental Commissioner of Ontario (Supplied photo)

Miller took the province's governing Liberals to task for not having a strategy to stem a continuing decline in Ontario's species and natural spaces, which are being threatened by habitat degradation, climate change, invasive species and pollution.

Ontario adopted a biodiversity strategy in 2005, but it expired last year, and so far the Liberals have not adopted an updated plan.

The government can't avoid its obligation to respond to an urgent crisis, Miller said. But the province is "ill prepared" to meet the challenge.

Threats to biodiversity have already taken their toll on the province and the problems it faces are troubling, he said.

Certain agricultural crops, such as fruits and alfalfa, will fail if the wild pollinators disappear, he said. Within 80 years, climate change could render northern Ontario inhospitable to spruce trees.

"It's going to get too warm and too dry to support black spruce in the areas where it's growing right now — that's a climate change consequence," he said.

"So what happens to a forestry industry that is depending on spruce trees in that zone?"

Maple trees — fundamental to Ontario forests — are facing a double threat from climate change and the Asian longhorned beetle, an invasive species that's coming up from New York state, Miller said.

"We're already losing our ash trees, like we lost our elm trees back in the 1960s," he said.

"If we lose our maple trees…Is that the Ontario we want to live in?"

Unless Ontario and other provinces take action, Canada's international commitments on biodiversity will be meaningless, he said.

The environmental commissioner also warns that Canada is getting a bad reputation among environmentalists after the federal government withdrew from the Kyoto climate treaty.