Chapter 19 4.2 Restoring grasslands with fire and soft seeds

In the fall of 1991, I stood with Steve Packard at his treasured place—a “Rembrandt found in an attic,” as he called it—on the edge of the woods outside Chicago.This is the prairie we are going to set on fire.Hundreds of acres of grass grew under scattered oaks, and the rustling, wind-tipped grass brushed our feet.We wandered over a meadow richer, more perfect, more real than Leopold had seen.Blending into this sea of ​​brown plants are hundreds of unusual species. "The main body of the North American prairie is grass." Packard shouted in the wind, "and most people notice the flowers in the advertisements." When I went, the flowers had withered, and the plain grass and trees seemed It seems a little boring.And this "boring" is precisely the key to recreating the entire ecosystem.

For this moment, Packard found a few small clearings full of flowers in the lush Illinois jungle back in the early 1980s.He sowed the seeds of prairie wildflowers in the field, and cleared the bushes around the open space to expand the area of ​​the open space.To stop the growth of non-native weeds, he sets the grass on fire.At first, he hoped that the fire would naturally do a good job of cleaning up.He wanted the fire to spread from the meadows into the bushes and burn the undergrowth.Then, due to the lack of oil in the trees, the fire would die out naturally.Packard told me, "We let the fire go as far as possible into the bush. Our mantra was, 'Let the fire decide.'"

However, the bushes did not burn as he had hoped.So Packard and his crew set out to clear the brush with an axe.Over a period of two years, they achieved satisfactory results.Wild ryegrass and goldenrods cover the new territory thickly.Each season, these rebuilders take it upon themselves to cut down the shrubs and sow the carefully selected North American prairie flowers they can find. However, in the third year, it was clear that something was wrong.Shade plants do not grow well and do not provide good fuel for seasonal burns.And the vigorously growing grasses were not from the North American prairie, but something Packard had never seen before.Gradually, the replanted areas reverted to bushes.

Packard began to wonder if anyone, including himself, could ever get out of burning a vacant lot for decades and getting nothing.He thought there must be another factor that had been overlooked to make a complete biological system.He started reading local botanical histories, researching eccentric species. He found that the unidentified species that thrived in clearings at the edge of oak fields belonged not to North American grasslands but to the savannah ecosystem—a grassland with trees.After studying the plants associated with the savannah, Packard quickly realized that other companion species, such as dandelions, frost gentians and desmodiums, dotted the edges of his reconstructed site.Even years earlier, he had discovered star-shaped flowers in full bloom.He once showed the flowering plants to experts at the university, because the star-shaped flower plants are so diverse that non-professionals cannot tell them apart. "What the hell is that?" he asked the botanist. "I can't find it in the book, and it's not listed in the National Encyclopedia of Species. What is it?" the botanist said, "I don't know. It might be a rare tree." Star flower plant of the savannah, but there's no savannah here, so it can't be that plant. Don't know what it is." People always turn a blind eye to what they don't want.Packard even told himself that the unusual wildflower must have happened by accident, or was misidentified."The savannah species were not what I originally wanted, so I tried to get rid of them," he recalls.

However, he keeps seeing them.He found more and more star-shaped flower plants in the field.It gradually dawned on Packard that the eccentric species was the dominant species in these clearings.Many other species associated with the savannah, he has not yet recognized.So he began scouting for samples—in corners of old cemeteries, along railroad embankments, and old carriageways—anywhere there might be scattered survivors of earlier ecosystems, collecting their seeds whenever possible. Packard looked at the seeds piled in the garage and had an epiphany.North American prairie seeds are dry, fluffy grass seeds mixed in a heap.The seeds of the gradually increasing savannah are "handfuls of colorful, bumpy, slimy soft gelatin", and the mature seeds are covered with pulp.These seeds are spread not by wind but by animals and birds.The thing he's been trying to recover—the coevolutionary system, the interlocking organic system—is not simply the North American prairie, but the prairie with trees: the savannah.

The pioneers of the Midwest called the wooded prairie "wilderness."Weedy undergrowth, and tall grass growing under sparse trees, was neither meadow nor forest—so it was wilderness to the early settlers.Almost entirely different species maintain a biome very different from that of the North American prairies.The wilderness of this savannah is especially dependent on fire, far more so than the North American prairies.And when the farmers came here and stopped burning, the wilderness quickly became a forest.By the turn of the century, this wilderness had all but disappeared, and little was recorded about its species composition.But once Packard formed a "search image" of the savannah in his head, he started seeing evidence of its existence everywhere.

Packard sowed mounds of savannah oddball slimy seeds.Within two years, the field was colorfully adorned with rare and forgotten wildflowers: wattle, blue-stemmed goldenrod, star flyweed, aster aster. The drought of 1988 withered the non-native weeds, but the "aboriginal people" who were resettled still thrived. In 1989, a pair of blue robins from the East (not seen in this country for decades) made a home in their familiar habitat—an event that Packard saw as "certification."University botanists called back, and the state appeared to have early records of the savannah's colorful plants.Biologists put it on the list of endangered species.Ellipse-leaved milkweed plants have returned to the recreated wilderness and are nowhere else in the state.Rare and endangered plants such as the white Phalaenopsis orchid and the light-colored twig have suddenly popped up on their own.Perhaps their seeds have been dormant—finding the right conditions for germination, between fire and other factors—or have been brought over by birds, such as visiting blue robins.A silver-blue butterfly that hadn't been seen in a decade across Illinois miraculously appeared on the outskirts of Chicago, where its favorite food, scorpion grass, grew in the emerging savannah.

"Ah," said the expert entomologist, "the Edwards slender butterfly is a typical savannah butterfly. But we haven't seen it. Are you sure it's a savannah?" Five years after reconstruction, Edwards Butterflies are already in full bloom in this area. "You build it, and they will come." This is the classic line in the movie "Fantasy Land".This is real.The more effort you put in, the more you get.Economists call this the "law of increasing returns," or the snowball effect.As the web of interconnectedness becomes tighter and tighter, it becomes easier to weave another piece.