An Ottawa scientist has identified what he believes to be the world's largest beaver dam in Wood Buffalo National Park in northern Alberta.

Ecologist Jean Thie, who is executive director of the Canadian Institute of Geomatics, said he discovered the 850-metre long dam while scanning satellite images for signs of climate change.

"They are one of the few species that really leave a footprint on the Earth that is visible from satellite," Thie told CBC News in an interview.

"In addition to looking at permafrost melting, I started looking at beaver dams and just scanning all of northern Canada."

The dam is located just south of Lac Clair, among the Birch Mountains and within the boundaries of the national park. It's about 190 kilometres northeast of Fort McMurray, Alta.

Thie said northern Alberta has the richest beaver habitat in the world, adding that he intends to continue to search for even larger dams in the area.

"These are some of the most amazing beaver landscapes in the world," he said. "I would not be surprised if we find a longer dam there than the one we have found so far."

The previously reported largest beaver dam was a 652-metre structure in Three Forks, Montana, Thie said.