I spent the first Saturday in May sitting in classrooms at Joliet Junior College, attending, along with a few hundred fellow enthusiasts, the eighth Northern Illinois Prairie Workshop.

The workshop organizers had provided us with 61 different classes to choose from, with topics ranging from “Prairie Management With Fire and Saw” to “Surveying Prairies for Reptiles and Amphibians” to “Seedbanks and Vegetation Establishment: Practical Considerations.”

There was a heavy bias toward the practical, a bias that reflected the makeup of the crowd. Most of the people who came are working on prairies. They are managers of government or private preserves, or they are volunteers restoring or protecting places like the Wolf Road Prairie in Westchester or the Indian Boundary Prairies in Markham or the prairies along the North Branch of the Chicago River. They come to a workshop looking for some help in coping with purple loosestrife, European buckthorn, and other invasive alien weeds, or seeking advice on how to organize a prescribed fire.

The fact that you could get that many outdoor people to spend a Saturday in May inside classrooms suggests that prairie restoration and management have somehow arrived, that they are now legitimate outdoor activities, like birdwatching or destroying endangered species with off-road vehicles. Someday maybe we’ll see a Mountain Dew commercial featuring a laughing gang of beautiful young people cutting down buckthorn shrubs.

There are restoration projects under way in all parts of Illinois, and all this activity produces a hopeful air at this meeting, which is quite different from the usual atmosphere at gatherings of environmentalists. The situation of the tall-grass prairie in Illinois has actually improved in measurable ways in the past 20 years.

Of course there was no way to go but up. Twenty years ago, almost nobody in Illinois knew what a tallgrass prairie was. They had nearly vanished from the landscape — we have four square miles left out of 40,000 — and they had vanished from the public mind as well. They were also nearly unrepresented in the state park system, and that didn’t bother very many people.

Today, although we have lost some more remnants, prairies are represented in the state park system and in the state nature preserve system; and restoration projects, some as big as 1,000 acres, are remaking prairies on land that’s grown mostly corn and soybeans for the past century and a half. The Illinois Department of Transportation is even planting prairie grasses and flowers along the roads. There are some on the Edens Expressway. The tall-grass prairie is reentering public consciousness.

If it hasn’t entered yours yet, I should explain that prairie is the French word for meadow. The French were the first Europeans to see the grasslands of Illinois, and they named this new thing after something familiar.

The grasslands of the North American interior began developing in the Eocene epoch about 50 million years ago after the Rocky Mountains arose in the west and threw a rain shadow across the heart of North America. With brief interruptions by glaciers, the prairie has been here ever since. With all that time to develop, the tall-grass prairie became a complex system of about 300 different plants and thousands of species of insects, mites, spiders, nematodes, birds, mammals, reptiles, and amphibians.

Periodic fires became part of the regular cycle of prairie life. The blazes burned away the dead plants from previous years, releasing nutrients into the soil, and also preventing trees from invading the grasslands.

The Illinois prairie was doomed as soon as settlers learned to plow it. The tall-grass prairie became the Corn Belt. The few unplowed prairies were invaded by alien weeds accidentally carried from Europe.

Prairie restorations are attempts to rebuild an ecosystem. The techniques are essentially agricultural. Gather the seed, clear the ground, plant, and then wait and hope. Ordinary farmers have the advantage of dealing with a small number of familiar domestic crops. Restorers are learning, by trial and error, to deal with the idiosyncracies of a couple hundred wild plants, species that have never been broken to the regular rhythms of the husbandman.

My first class at the workshop had no apparent connection with prairies. Steven Apfelbaum and Alan Haney have been studying the forests of the Boundary Waters Canoe Area in northern Minnesota with particular emphasis on the jack pine woods.

A jack pine woods, like a prairie, is a fire-adapted community. The difference lies mainly in how often fire strikes. A prairie may burn nearly every year. A jack pine woods burns, on the average, once every 75 to 100 years.

The fires can be quite destructive, killing all, or nearly all, of the trees and reducing the detritus on the forest floor to ash. The soil is suddenly more fertile, the minerals locked up in dead wood and old pine needles released by the fire. The brilliant purple fireweed and other wildflowers spring up on a sunny forest floor. Woodpeckers invade to live on the beetles and other insects that are eating the dead tree trunks. Flycatchers, birds that catch flying insects on short sallies from exposed perches, can see their prey better on the open land.

Plants and animals succeed each other in regular patterns as the new forest grows. Chestnut-sided warblers like a newly burned area. Moose come in somewhat later when the woody browse they like to eat has grown bigger.

So a jack pine woods recycles itself. It is reborn in fire, returned to infancy with all the possibilities of life before it.

Think of that cycle spread out over space rather than time, and you have the landscape of the Boundary Waters, with small patches of land that burned last year next to other patches that burned five years ago and still others that haven’t seen a fire since 1910. The mosaic of even-aged communities constantly creates opportunities for all plants and animals. Black-backed three-toed woodpeckers can find newly burned tree trunks and Cape May warblers can find tall trees to hunt in.

A cycle this grand is possible only because the BWCA is a million-acre wilderness bordered on the north by a Canadian wilderness of similar size. You could not accomplish a cycle like this if the unbroken forest was shattered into a few small, widely scattered fragments separated by pavement and other hostile environments.

But the remains of the Illinois prairie consist of just such scattered fragments. So our problem is to sustain an ecosystem that has been knocked to pieces. The difficulties involved in that project were central to the message Ron Panzer delivered in a class entitled “Managing Prairies and Savannas for Insect Conservation.”

Insects are essential to the life of the prairie, and they are very vulnerable. They must reproduce successfully every year or they will disappear. They are often tied to host plants, individual species essential as food and shelter for both larvae and adults. Often, for reasons still mysterious, you can find a particular bug living on only one clump of host plants in an entire prairie, even though there are many such clumps all looking equally inviting.

So what happens if a fire sweeps through that one essential clump of plants? The insects will be killed. When the prairie covered thousands of square miles in an unbroken sweep, this local destruction would make little difference. Insects from neighboring areas that had escaped the fire would recolonize the devastated portions of the land. But when the neighbors are fast-food restaurants or split-level houses, the destruction is likely to be permanent.

Panzer offered us some suggestions for avoiding local extinctions of species. We should burn sparingly, he said, and never burn the entire preserve at once. But the most important thing is to have big preserves where large populations can exist and provide a cushion against catastrophe.

Panzer was talking about insects on small prairie preserves, but his remarks are more broadly applicable. Wild plants and animals are increasingly confined to islands of wildness in a human landscape. The Boundary Waters Canoe Area is big enough to provide a mainland for most species, but timber wolves, animals whose hunting range may exceed 100 square miles, are islanded even in the BWCA. So are the grizzly bears of Montana and the elephants of the Serengeti Plain. The fate of most of the world’s creatures now depends on our ability to learn how to keep them alive on islands.