From the air, the roof of a sprawling compound in Manitoba is almost indistinguishable from the marsh that surrounds it.

The long grasses, reeds and bulrushes that populate the nearby ponds and wetlands appear almost to have reclaimed the 2,600 square-metre roof of the building.

It's as if the plants have migrated from the marsh and merged seamlessly with the structure, taking root and creating habitat for the native animals and insects that would otherwise be living next to the equivalent of an elevated asphalt parking lot.

The building -- Ducks Unlimited's headquarters north of Winnipeg, Man. -- is a made-in-Canada example of a cutting-edge 'green,' or 'living roof.' The phenomenon is blossoming across Canada and the Western world with everyone from librarians to big-business executives creating pockets of green in otherwise lifeless rooftops in the concrete jungle.

Simply defined, a green roof consists of a growing medium such as peat or topsoil, placed over a waterproof membrane, with the goal of supporting vegetation.

The Ducks Unlimited roof is one of the grandfathers of the young movement in Canada. It was first built back in 1992 with the primary goal of creating, rather than erasing, bird habitat on the major migratory flight path where the office was being built.

The roof has been revamped and tweaked many times since then to improve performance and fix problems, but the goals of creating habitat and reducing the environmental footprint of the building have always remained at the forefront, said Paula Grieef, resident naturalist at the Oak Hammock Marsh Interpretive Centre.

"The idea was that if you were a duck or goose flying over, we didn't want it to look like a building, we wanted it to look like habitat," Grieef told CTV.ca.

"Habitat loss is the number one problem for most species in Canada, so if anyone, including us, can provide extra habitat it's a good thing."

At the moment, she said, six ducks and one goose call the roof home, in addition to countless insects, birds and other animals.

In addition to the environmental and financial benefits, the roof also serves as a teaching tool for student groups, Grieef said.

Canada emerging as a leader

Canada is quietly emerging as a leader in the green roof movement. A number of Canadian projects are featured on greenroofs.com, a publication that tracks developments in the global green roof movement.

In B.C., the Vancouver Convention Centre has the largest green roof in Canada. Not far away, the city's flagship library is planted with ground cover and fescues that bring life to the roof in a design intended to evoke the path of the Fraser River.

In Toronto, where city councillors are considering a bylaw that would require new buildings to incorporate a green roof component, the living roof on the Fairmont Royal York hotel boasts honey bee hives and herbs that are incorporated into the hotel restaurant's menu.

And Vancouver's Fairmont Waterfront hotel hosts an apple orchard, where fruit ripen in the shadow of nearby skyscrapers.

Even the Ford Motor Company is going green. The 10-acre roof of its Dearborn, Mich. plant boasts the largest green factory roof in the world, with swaths of sedums planted to reduce storm water runoff.

Pros and cons of going green

There are a number of reasons why architects, builders and property owners are becoming attracted to the idea of green roofs, said Fiona Crofton, a professor at the University of British Columbia who specializes in architecture and sustainability issues.

When built and designed properly, she said, green roofs can reduce sewer runoff by capturing and retaining rain water, they provide space for urban gardens, clean the air and help combat climate change, to name a few of the benefits.

And although they are typically more expensive to install than traditional roofs, they usually pay for themselves over time through reduced heating and cooling costs, Crofton said.

And on top of all that, installing a green roof is also something one can simply feel good about.

"You get to feel like you're doing the right thing," Crofton said.

"And potentially it may extend public space and provide a vehicle, if used properly, to promote more interaction among people and our culture, which now is very individualistic and containered off."

Back at the marsh, Grieef admitted there are some disadvantages to green roofs. Because much of the technology is new some of the bugs are still being worked out. And at up to three times the price of a traditional roof, the initial investment cost can be daunting.

It can also be difficult to maintain a field or garden when it is located on a rooftop, Grieef says. Just getting a lawnmower up there can be tough. As well, in the case of the DU project, managers have wrestled with how to properly burn back the native grasses, fully aware that one wrong move could set the building up in flames.

Another challenge, she joked, is helping the young ducklings off the roof for the first time.

Crofton agreed there are challenges, and said architects, builders and owners all still have a lot to learn about turning roof space -- and maybe one day vertical wall space as well -- into productive patches of life.

But the fact there are people striving to meet those goals, and that practical, working examples of green roofs actually exist for her to show her students, is a good thing.

What is now a reality was little more than a concept 15 years ago, Crofton said.

"My hopeful and optimistic side says there's a lot of really good people doing a lot of really good things, and the more we have of that the better off we'll be."