The Mikisew Cree First Nation is seeking to have Wood Buffalo National Park, a crown jewel of Canada's national park system, classified as "at-risk" internationally in an effort to protect it from oil sands and hydroelectric projects.

The Mikisew sent a request on Monday to the United Nations Educational, Scientific and Cultural Organization (UNESCO) to reclassify the park from its current status as a World Heritage Site. The northern Alberta park received the designation because it has the world's largest freshwater delta, at the meeting place of the Peace and Athabasca Rivers. The Mikisew say water levels in the park have dropped over the past decade and contaminant levels have increased.

The Alberta and federal governments are not obligated to make regulatory changes because of UNESCO designations, but the issue could bring further international attention to the oil sands. The only North American site currently on the at-risk list is Everglades National Park in Florida.

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The designation "at-risk" means a site is in danger of losing the attribute that made it a World Heritage Site.

The two rivers that flow into Wood Buffalo, the country's largest national park, are tangled with Western Canada's energy industry. The winding Peace River produces much of the hydroelectricity that powers the Pacific Coast, while the Athabasca River flows through Fort McMurray and is used in oil sands development.

Members of the Mikisew Cree say they have watched water levels drop for decades across the 800,000-acre delta, a nesting place for endangered whooping cranes. The delta and the park are the small community's home, where locals hunt, fish and trap.

"We are already deeply concerned about the impact of industrial activity on our traditional lands," Mikisew Chief Steve Courtoreille said in a statement. "We are using every possible means before it is too late to save the land that has supported our people for millennia."

Melody Lepine, a director for the Mikisew, said she was shocked this summer when she saw the fast spread of thistle weed in the delta. An invasive species, thistle weed grows in dried-out areas that were once underwater. To complicate matters, the 5,000 bison in the park avoid the thistle, limiting their access to water.

Ms. Lepine said she expects the worst from future projects, including BC Hydro's proposed Site-C dam on the Peace River. "We want Canada and the world to consider that this place is endangered, because it is," she said.

Site C, which has been in the works since the 1970s, now has federal and provincial approval.

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According to Dave Conway, a spokesman for BC Hydro, the Site C dam will not affect the delta.

"This project is 1,100-kilometres upstream. It does not hold water; it lets water through. There would be no effect from this project on any aspect of the environment in the Peace-Athabasca delta, according to a federal-provincial panel," Mr. Conway said.

The Mikisew are also asking governments to create a buffer zone where development is banned in an area between 50 and 100 kilometres around the park, citing a proposal for an oil sands mine just south of the park boundaries as a concern.

The sprawling Frontier Oil Sands Mine could produce 240,000 barrels of oil daily after opening in 2021. It is currently undergoing federal review. A buffer would imperil the proposed mine, said Alison Ronson, executive director of the Canadian Parks and Wilderness Society in northern Alberta. She said the request to the UN could force the government to take a more active role in regulating the oil sands.

"This is a site that is supposed to be protected, and just because borders are drawn on a map, the park is not immune to what's going on around it," Ms. Ronson said.

Ms. Ronson's organization had success earlier in 2014 when UNESCO called on Canadian officials to create a buffer to protect Gros Morne National Park on Newfoundland's west coast from proposed oil drilling.