Tuesday, February 3, 2009

Grass is good: restoring prairie

Should anyone be surprised that grassland birds and other prairie creatures are in trouble when human enterprise has removed somewhere between 70 and 75% of the grass they depend upon?

Any hope of helping grasslands ecology recover some of its former glory will require large scale restoration of prairie ecotypes in a patchy diversity. No one has the science to restore grassland to the fully functioning regime that greeted settlers when they first put it to the plow, but the more researchers and parks managers try to restore native grassland the more they learn about how to create a facsimile of the original.

When I was last at Grasslands National Park I saw a machine with a rotating drum on the back bristling with thousands of speargrass seeds. They use it to collect native grass seed for restoration projects on parks land that had been cultivated. In the last decade Parks Canada and its corps of local volunteers have seeded 630 acres back to native grass. This Parks Canada web page on the project doesn't mention anything about the struggle to keep weeds and invasive species out of the seeded land; nor is there any mention of research to see whether grassland insects, birds, and other animals are able to use the restored prairie for foraging and nesting habitat.

If grassland restoration is to work and have a net benefit for the species that need it most, biologists will have to do the monitoring to ensure that restored grasslands are not creating what they call "ecological traps," i.e. land that attracts nesting birds, for example, but produces very few young that reach maturity. Sink habitats can be a net loss for species already in decline.

As well as government agencies, organizations such as the Nature Conservancy and the Nature Conservancy of Canada are beginning to find ways to restore native grassland in places all over North America. Here is a snippet from a new article called "Restoration Activity Accelerates in Key Missouri Prairie Landscapes," describing the Nature Conservancy's work on the Missouri-Iowa border. There the struggle is keeping away woody growth:

"The Conservancy’s goal in these grasslands is to restore and protect functioning tallgrass prairies and provide critical habitat for grassland species. Working closely with private landowners and partners, like MDC, the Conservancy is using a myriad of management techniques, including prescribed fire, conservation grazing, tree removal and invasive species control to mimic the land’s natural cycles and bring back the original habitat for the benefit of prairie chickens and the other grassland species. Today, less than one percent remains of the original tallgrass prairie that once covered a third of Missouri."

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