Physics is our mission, but buffalo may be Fermilab's main attraction for visitors. What are buffalo doing at a physics laboratory? (The oft-told tale that they are Fermilab's equivalent to the canary in the mineshaft, living Geiger counters to warn of radioactivity, is strictly fiction. The Fermilab site does not present a radiation hazard, and Fermilab buffalo do not glow in the dark.) Our buffalo herd carries on a tradition begun by Robert Wilson, the Laboratory's first director, to recognize and strengthen Fermilab's connection to our prairie heritage. Wilson brought the first American bison, a bull and four cows, to Fermilab in 1969; and in 1971 the Illinois Department of Conservation gave us 21 more. Today's herd are descendents of those first animals.
Wild buffalo once numbered in the tens of millions; the familiar events of their near-extinction left their number under a thousand. Public and private breeding programs have restored the current total to roughly 160,000 in the United States. The Fermilab herd has about 45; our pasture can support up to 70. When the herd gets too big, the Laboratory holds a buffalo auction. Besides grazing, Fermilab's buffalo eat grain and hay baled on the Laboratory site. Gestation takes nine months, and most calves are born in the spring. Regular veterinary care keeps the herd in good health. Although they look placid, buffalo have the undomesticated personality of the wild. Like physicists, they have been described as "cantankerous" by those who have tried to herd them. A double fence around the Fermilab pasture protects the buffalo and the public from each other. Advice from an experienced hand: "Don't turn your back on a buffalo."
The official state surveyor's notes from 1840, describing the area that Fermilab now occupies, refer again and again to "1st rate prairie," "rich, open prairie land," and "prairie land, rich and fit for cultivation." The last description proved prophetic: 150 years later, Illinois' prairies have virtually disappeared, turned over to the production of soybeans and corn. Yet in some areas, among them Fermilab, efforts have begun to retrieve some of the awesome beauty of the old prairies, as well as the biodiversity of native grassland ecosystems. Since 1975, the Fermilab Prairie Committee has gradually increased the acreage dedicated to reconstructing the native grassland. Volunteers from the Laboratory staff and interested people from the community nurse the prairie back to life by preparing the land, planting seeds, and managing the result.
How do you bring back a prairie? Plowing and disc harrowing prepare the ground for seeds from dozens of prairie plant species, broadcast over the field. Volunteers gather the seeds, by machine or by hand, then clean them meticulously, and prepare them to germinate by cold treatment or scarifying the seeds. After planting, maintaining the prairie community may require overseeding with some kinds of seeds. Most important, healthy prairies require regular annual burning to rejuvenate the ecosystem. Maintaining a reconstructed prairie is a constant struggle between native species and the aggressive European forage grasses and weeds that have infiltrated the Midwest in the last hundred years. Burning the prairie encourages the native grasses (adapted to eons of natural prairie fires) over the introduced weedy species. Volunteers must wait for just the right combination of moisture, weather and wind to burn the dry plants safely, carefully setting backfires and creating firebreaks to control the intense flames of the headfire that follows, running with the wind.
Eventually, the volunteers' efforts will produce an ecosystem that closely resembles the prairie the settlers found. We haven't yet reached that stage at Fermilab, but our prairie is now home to many native species that weren't here when Fermilab moved in. These days, in Fermilab grasslands we commonly see plants such as big bluestem, Indian grass, prairie dropseed, compass plant, prairie dock, shooting star, gayfeather, false indigo, wild quinine, golden alexander, yellow and purple coneflowers, rosinweed, wild bergamot, lead plant, rattlesnake master and butterfly weed, whose colorful names suggest their place in an older culture and history. Now that the plants have arrived, those who eat them have begun to move in to complete the system. Insects such as butterflies, planthoppers and bees use the prairie plants; and prairie birds, including the bobolink, grasshopper sparrow, dickcissel and the endangered upland sandpiper, are frequent visitors.