Prairie restoration is a way to protect and restore prairie lands that were lost because of activities like farming, building homes, or starting businesses. The main goal is to bring these areas and their ecosystems back to how they looked before they were damaged.
In the United States, after the Black Hawk War ended in the mid-1830s, people from northern Europe and the northeastern U.S. moved to the region and began farming. They cleared the tall grasses and wildflowers that once covered the land. By 1849, most prairie grass species had disappeared to make space for crops like soybeans and corn. Restored prairies and the few grasses that survived the 1800s farming represent only a small part of the large grasslands that once stretched from western Ohio to the Rocky Mountains and from southern Canada to Texas. For example, the state of Illinois once had over 35,000 square miles (91,000 km²) of prairie land, but now only 3 square miles (7.8 km²) of that original land remains. Overfarming, drought, and the lack of protection from the elements (since the grasses were no longer holding the soil together) led to the Dust Bowls of the 1930s.
Restoration efforts help address problems like soil erosion and the loss of plant and animal life in areas where prairie grasses once lived. In Europe, when restoring farmland with prairie grasses, common methods include letting nature regrow naturally, planting mixtures of seeds, moving plants from one place to another, and removing and moving topsoil. To care for these grasses, people often use controlled fires, which help grasses grow taller and stronger and return nutrients to the soil.
Although full restoration of an area’s original diversity is difficult, these efforts still help natural ecosystems recover. This is helped further by bringing back important organisms from the soil of native plants. Prairie soil is also good at storing carbon. As carbon sinks, these soils absorb carbon from the air, which helps balance the amount of carbon in the atmosphere. This stored carbon supports the survival of many species in the prairie ecosystem.
Purpose
Erosion happens when forces on the Earth's surface wear away the ground. In areas once covered by prairie grasses, the loss of deep, fibrous roots from tallgrass plants left soil loose and exposed. Prairie restoration helps protect topsoil, which is often lost to wind and rain (especially heavy rains linked to climate change) when prairies are turned into farmland for crops like corn, barley, and wheat. Over time, erosion harms soil health and reduces its ability to support crops long-term.
Restoring prairies brings back the deep root systems of native grasses, which help hold soil together and reduce water erosion by filtering rainwater. Prairie soil also stores carbon, a gas that traps heat in the atmosphere. Human activities release about 40% of this carbon, which worsens global warming. Prairie grasses take in carbon through photosynthesis and store it in the soil. When undisturbed, prairie soil acts as a carbon sink, absorbing more carbon than it releases.
Many prairie plants are strong and can survive droughts, extreme temperatures, disease, and pests. They are used in xeriscaping, a type of landscaping that uses little water, in dry areas of the American West. On a larger scale, restored prairies help store carbon, support biodiversity for over 3,000 species, and improve groundwater quality. Studies in Iowa show that converting farmland back to prairie over 10 years can reduce pollution from chemicals in water, improving water security.
Prairie restoration can happen on any scale, including small areas like backyard micro-prairies. These are small prairie habitats, often less than one acre, located near cities or developed land. Micro-prairies support native plants and animals, provide food for pollinators like butterflies, and help maintain biodiversity. They also offer nesting areas for insects and reduce the risk of habitat loss or pesticide harm.
Prairie plants help store carbon in the soil through deep roots and fast growth. They also improve water quality by trapping pollutants in the air and soil. The variety of plants and microbes in prairie soil can break down harmful substances. Prairie plants can absorb heavy metals and excess nutrients from water and soil, helping ecosystems stay healthy.
Micro-prairies can help ecosystems and biodiversity, but they may cause problems if not managed properly. For example, non-native plants might grow better than native ones, reducing biodiversity. If not cared for, prairies might grow too much and increase fire risk. Regular mowing or burning can help manage this. Standing water in micro-prairies might also attract mosquitoes, but proper planning can prevent this.
In cities, permaculture—a method inspired by natural ecosystems—can help create micro-prairies. Permaculture uses sustainable practices to design systems that support both people and nature. It includes growing diverse plants together to help each other grow and mimics natural patterns. Micro-prairies also teach people about protecting native habitats and the importance of restoring ecosystems.
Types of plants
Some common tallgrass prairie grasses are big bluestem, indiangrass, and switchgrass. Midgrass and shortgrass prairies include plants like little bluestem, side oats grama, and buffalograss. Many prairie forbs, which are non-grass flowering plants, have special features that help them survive when eaten by animals like American bison. Some forbs have hairy leaves that help protect them from cold and reduce water loss. Many forbs also contain special chemicals that were discovered by indigenous peoples and are still used today.
Early prairie restoration projects often focused on a few main grass species, with little attention to where the seeds came from. Over time, restorers learned that using a wide variety of plant species and seeds from local plants is important for successful restoration.
Planting and aftercare of prairie plants
In Europe, when restoring land that was once used for farming by planting prairie grasses, the most common methods include: natural growth, planting seed mixtures, moving plants from other areas, and removing and moving topsoil. Natural growth works well when quick results are not needed and when there are many seeds or plants available to start new growth. Seed mixtures can have few or many different types of seeds. Mixtures with few types are useful for covering large areas quickly. Mixtures with many types (which are more expensive and take longer to grow) are used for smaller areas. Combining large areas with few seed types and smaller areas with many seed types helps create rich areas that allow nearby areas to naturally grow new plants over time. This supports ongoing natural restoration.
Fire plays an important role in the success of grasslands, whether they are large or small, because grasslands depend on fire to survive. Controlled burns, which require permission, are recommended every 4–8 years (after two growing seasons) to remove dead plants, stop other plants like trees from growing too much, and return nutrients to the soil to help new plants grow. A more wildlife-friendly alternative is to burn 1/4 to 1/8 of an area each year. This allows animals to stay in their homes while still achieving the benefits of fire. Native Americans may have also used fire to control pests like ticks. These planned burns help grasses grow taller, produce more seeds, and flower more. If controlled burns are not possible, mowing the grass in sections over time is a recommended alternative.
A newer method is holistic management, which uses livestock instead of important species like bison to help restore grasslands. Some areas have bison, which helps protect the species. This method uses animals to do the work of mowing, which mimics natural processes more closely. Holistic management can also use fire, but only in limited ways and together with the mowing done by animals. In parts of Central Asia, human activities like grazing livestock greatly influence how grasses grow.
In 1990, in South Africa, de Lange and Boucher found that smoke can help prairie grass seeds grow. Smoke helps some seeds break their dormancy, or start growing. Since then, this method has been used in parts of South Africa, Australia, and North America.
Prairie contributors
Some prairie restoration projects have been completed and kept in good condition by conservation groups. One example is the Midewin National Tallgrass Prairie in Wilmington, Illinois. This project is managed by the U.S. Department of Agriculture, Forest Service, and the Illinois Department of Natural Resources. It is located on part of the Joliet Army Ammunition Plant, an area that was once polluted by TNT production. Since 1997, this project has made about 15,000 acres (61 km²) of restored prairie available to the public.
Another large restoration project is located at Fermilab, a U.S. government laboratory for studying atoms in Batavia, Illinois. Fermilab covers 6,800 acres (28 km²) of land that was once farmland. The prairie restoration project includes about 1,000 acres (4.0 km²) of this area. This project started in 1975 and is still ongoing today with the help of Fermilab employees, teachers, botanists, and volunteers.