Short answers, pulled from the story.
Prairie restoration is a conservation effort aimed at restoring prairie lands destroyed by industrial, agricultural, commercial, or residential development. Its primary goal is returning affected areas and ecosystems to their state before that depletion.
After the Black Hawk War subsided in the mid-1830s, settlers from northern Europe and the northeastern U.S. plowed up the tallgrasses and wildflowers to plant crops. By 1849, most prairie grass species had disappeared to make room for crops like soybeans and corn. Decades of over-farming and drought later contributed to the Dust Bowls of the 1930s.
Illinois once held over 35,000 square miles, about 91,000 square kilometers, of prairie land. Today only about 3 square miles, roughly 7.8 square kilometers, of that original prairie remains.
In Europe, the most common prairie restoration techniques include spontaneous succession, sowing seed mixtures, transferring plant material, and removing and transferring topsoil. Prescribed fire is also widely used to encourage taller, stronger regrowth and recycle soil nutrients.
A micro-prairie is a mini prairie habitat, typically smaller than one acre, usually isolated within developed or urban land. Micro-prairies can enrich soil, fight erosion, absorb rainfall, and support pollinators despite their small size.
Midewin National Tallgrass Prairie, in Wilmington, Illinois, has opened roughly 15,000 acres of restored prairie to the public since 1997. Fermilab, a U.S. government atomic accelerator laboratory in Batavia, Illinois, has restored approximately 1,000 acres of its 6,800-acre site since the project began in 1975.