Rooftop prairie

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(Host) Though 99 percent of America’s natural prairies have been lost, commentator Ruth Page describes a little one atop a building in Chicago that offers a sampling of some natural prairie plants.

(Page) Nowadays, if you want a true American prairie, it’s best to plant your own, as has been done atop Chicago’s City Hall. Gardens atop buildings are not unusual, as city folks find they have no room at ground level but plenty up high.

Dozens of nature writers and scientists deplore the terrible loss of America’s historic prairies that once spread richly across the entire midwest, providing a varied ecosystem with hundreds of animal and plant species. Only about one percent remains of the grassy oceans formed after the last Ice Age ended. After centuries of evolution, that vast ecosystem is gone.

Sixty million one-ton bison once cropped the grass and made large wallows, or ponds, to escape mosquitoes. These provided water to smaller fry and let rain percolate down to keep renewing the aquifer. Lack of trees, and fire danger caused many animals to live underground; they, notably the millions of prairie dogs, dug tunnels that also invited water to seep to the aquifers, and to enrich river flows. Dozens of animal and bird species used prairie dog tunnels to escape fire, protect young, and elude predators. Fires burned off the tall grasses, making space for young plants rich with nourishment for grazers.

Prairie dogs have been misunderstood until very recently. They were thought to spoil grazing land (in fact, they enrich it) so millions were killed in the past 150 or more years, under the auspices of the government. Animals depending on them suffered.

Flocks of migrating birds, including the regal cranes, and smaller birds and ducks with their brilliant colors, still make a rich panorama during seasonal flights, but their numbers have greatly diminished as the prairies died. Our seas of grass have given way to vast, one-crop farms using damaging pesticides and herbicides. River flow is reduced, the water table has fallen, and the immense variety of a thriving, complex ecosystem of plants and animals has been unimaginably reduced. We are poorer for it.

Chicago’s 20,000 square foot City Hall garden includes some 160 different plants, including prairie natives like big bluestem and crabapple and hawthorn trees. The city’s environment chief points out the gardens help fight air pollution. They also cover formerly dark roofs that otherwise absorb the sun’s heat, driving summer temperatures up by 5 or 6 degrees. Gardens, and the little pieces of natural prairie protected by environmental organizations, at least allow us to see a small portion of what we’ve lost.

Audubon magazine says there are 50 public and private buildings in Chicago with a total of 600,000 square feet of gardens.

Roof gardens have become more common in other cities, too, here and in Europe. Plants are the umbilical cord that connects humans to nature.

This is Ruth Page discussing Chicago’s tiny, unique prairie.

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