TORONTO — Imagine Ontario without a Canadian icon -- the maple leaf.

That could become a reality within a decade if the governing Liberals don't get their act together to deal with significant threats to biodiversity, Ontario's environment watchdog warned Tuesday.

"We could lose sugar maple trees from southern Ontario," Gord Miller, the province's environmental commissioner, 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."

Miller took the government 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.

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

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

Certain agricultural crops, such as fruits and alfalfa, will fail if bees 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 Asian longhorned beetles, an invasive species coming up from New York state, Miller said.

If the beetles take hold within five or six years, the maples will be "in trouble within a decade," he said. The impact of climate change is a still a few decades away.

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

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

Natural Resources and Fisheries Minister Michael Gravelle said he doesn't believe it will come to that.

"We can hopefully find our way through this," he said.

He insisted the province is doing everything it can to protect maples from the beetles, but acknowledged that there's currently no program to monitor the species in Ontario.

Ottawa has taken the "lead responsibility" in the fight against the longhorned beetle, Gravelle said.

"We're committed to working with the federal government," he said. "We'll continue to do so."

With the Liberals poised to make significant cuts in some departments, critics worry that those charged with protecting the environment will be the first to face the chopping block.

The government has warned ministries other than health and education that they may face dramatic cuts this year as they struggle to slay a $16-billion deficit.

Last November, Miller warned that budgets for the environment and natural resources ministries had been slashed so much the province was at a "tipping point."

Those ministries already can't do the job they need to do to protect the environment, said NDP critic Jonah Schein.

"The maple leaf is on our flag, it's our hockey team here in Toronto," he said.

"We can't afford to continue to go down this road."

Ontario's economy can't afford it either, said Green party Leader Mike Schreiner. Biodiversity is "intimately connected" to the province's ability to generate revenue.

"If we lose our pollinators, that threatens our food and agricultural industry -- the second largest employer in this province," he said.

"If we lose our maple trees, it not only threatens our identity, it threatens our ability to produce maple syrup, which is a major crop in this province."

Gravelle insists his government is committed to the environment, passing legislation over the years to protect endangered species, the Greenbelt in southern Ontario and the northern boreal forest.