UNESCO World Heritage Sites in Canada threatened most often by oil, gas and mining

Mining and oil and gas extraction account for nearly a third of threats to UNESCO World Heritage Sites in Canada over the last 30 years, according to the international organization.

A total of 75 threats against nine designated natural and cultural sites have been documented by the United Nations Educational, Scientific and Cultural Organization's State of Conservation database since 1985.

Of those, 23 belong to a category called "physical resource extraction," which consists of mining and oil and gas operations.

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The next most common threat types are management and institutional factors (13), service infrastructure (10), transportation infrastructure (8) and buildings and development (7).

Most of the threats occurred between 2000 and 2013.

Peter Tyedmers, a professor at the School for Resource and Environmental Studies at Dalhousie University in Nova Scotia, linked the threats from resource extraction to energy prices, which increased during that same time.

"It's not surprising that, when prices are high, people are looking at new opportunities to develop," he said.

The threats against Canadian heritage sites were identified in a series of 41 UNESCO reports since 1985.

Wood Buffalo National Park in northern Alberta was the subject of the greatest number those reports, with nine in total, followed by the Historic District of Old Québec and Canadian Rocky Mountain Parks, which each had eight.

Number of threat reports:

• Wood Buffalo National Park: 9
• Historic District of Old Québec: 8
• Canadian Rocky Mountain Parks: 8
• Gros Morne National Park: 5
• Nahanni National Park: 5
• Waterton Glacier International Peace Park: 2
• Dinosaur Provincial Park: 2
• Kluane / Wrangell-St. Elias / Glacier Bay / Tatshenshini-Alsek: 1
• Miguasha National Park: 1

The latest report for Wood Buffalo dates back to 2015.

In that document, UNESCO "notes with concern the environmental impacts on the Peace-Athabasca Delta from hydro-electric dams, oil sands development, and proposed open-pit mining in the vicinity of the property, which could negatively impact its outstanding universal value."

"Large industrial development of Alberta's oil sands region, located upstream of the park, is releasing contaminants, extracting significant volumes of water from the Athabasca River system, and disrupting migratory bird movements," the report reads.

It also mentions the Site C dam, a hydroelectric project in northeastern British Columbia, and other dams outside the park that "are affecting its hydrology and biodiversity."

Last place on Earth where bison and wolves interact

That's concerning to Alison Ronson, executive director with the Canadian Parks and Wilderness Society (CPAWS) in Northern Alberta.

"Wood Buffalo National Park is both important to Canada and internationally because it contains one of the world's largest inland freshwater delta," Ronson said.

"It also is the only nesting place for the endangered whooping crane in North America and the last place on Earth where bisons and wolves interact in a natural predator-prey dynamic."

UNESCO has requested an environmental assessment in the region, and is asking Canada "not to take any decision related to any of these development projects that would be difficult to reverse."

Parks Canada wrote in an email that environmental assessments and procedures to issue licences are in place to protect Wood Buffalo National Park.

A UNESCO mission will visit Wood Buffalo from Sept. 24 to Oct. 5.