The world’s most endangered ecosystem

Ask any Canadian kid to name the world’s most endangered ecosystem and chances are you’ll hear one of the following answers: rainforests or coral reefs.

There is no question that both of these are endangered. These ecosystems are the focus of international campaigns to protect hot spots of species diversity. They are the focus of education and awareness campaigns shown on Canadian news and taught in Canadian classrooms.

Now, what if I told you the world’s most endangered ecosystem is a habitat much closer to home than you might think.

Endangerment comes down to risk; the risk of losing a species, habitat or ecosystem for future generations. When we look at the risk factors for endangerment — past loss, current amount of conservation, potential for future loss — the winners (actually the losers) are temperate grasslands, including our Canadian Prairies.

There are many reasons why temperate grasslands are endangered. They are the original breadbasket of the world. More than 50 percent have been converted to crops and other land uses.

Much of the remaining grasslands are intensively grazed, replacing what were some of the planet’s greatest concentrations of wild grazing animals with cattle, goats and sheep.

The loss and continued threats to temperate grasslands were recognized in 2008, when the International Union for the Conservation of Nature declared temperate grasslands as the world’s most endangered ecosystem.

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Two years later, a paper published in the Journal of Ecological Letters about global habitat loss and conservation found that temperate grasslands had the highest conservation risk index compared to all other terrestrial ecosystems.

This high risk is a result of large-scale conversion of temperate grasslands and very few protected areas. A recent paper in the journal Science examined habitat types around the world, and temperate grassland was identified as the ecosystem with the greatest impacts and land use pressures.

More than 70 percent of Canada’s prairie grasslands has been converted. A 2010 report on the status and trends of Canada’s major habitat types found that our grasslands are the only major ecosystem type in our country that is impaired and continuing to decline.

The endangerment of grassland habitat in Canada has cascaded into the endangerment of many grassland species. More than 60 Canadian species at risk depend on this habitat, including species that symbolize our grasslands, such as plains bison, swift fox and greater sage grouse.

The loss of Canada’s grasslands is a loss for Canadians. In an ecosystem that is created by a lack of water, grasslands are critical for allowing water to infiltrate into the ground, providing base flow to rivers and streams, and holding water during floods.

Grasslands are important for carbon storage, with intact native prairies proving to be particularly effective at sequestration and long-term storage in their deep, extensive root networks.

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Many of Canada’s grasslands have a long history of sustainable cattle grazing. This grazing has supported generations of prairie ranchers, can help to maintain grassland health and benefits many species of prairie wildlife.

The Nature Conservancy of Canada has protected more than 197,684 acres of grasslands in properties, including large, intact areas such as Old Man on His Back in southwestern Saskatchewan.

In addition to new protected areas, there is also a key, and immediate, opportunity to conserve large areas of prairie and maintain local ranching economies by protecting community pastures.

Here in Canada, we have opportunities to protect and restore habitats that are important for Canadians, and important for the world. We have an opportunity to protect and restore our grasslands.

Dan Kraus is a scientist with the Nature Conservancy of Canada.

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