What is a Prairie?

A prairie is a type of ecosystem made mostly of grasses, but it also has flowering plants along with some shrubs and trees. More than 100 plant species can occur in a prairie of less than 5 acres. Prairies can contain more plant diversity than a rain forest!

Big bluestem in bloom at Lawther-Deer Park Prairie. Photo by Don Verser.

Grasslands are found around the world, but they go by different names, such as steppes in Asia. They are one of the most recently developed ecosystems—formed about 8,000 years ago. The word prairie generally refers to grasslands in North America, especially the tallgrass prairie. About one percent of this North American tallgrass prairie still exists.

The “big four” grasses of the tallgrass prairie are big bluestem, little bluestem, Indiangrass and switchgrass. These grasses can grow as tall as ten feet in the Midwestern prairies. The soil underneath a prairie is a dense tangle of roots and bulbs. Some prairie plants put out roots that extend 12 feet below the prairie surface. Each year some of the roots die. Large quantities of organic matter are added to the soil as roots die and decompose making a fertile soil. These rich soils were why prairies were plowed for croplands.

Prairies have a topography, even when they look flat. While the topography of Blackland prairies is gently rolling to nearly level, they contain subtle drainages. The soil is characterized by fairly uniform dark-colored, alkaline clays (vertisols) interspersed with some gray, acid sandy loams. The microtopography includes shallow depressions called gilgai or “buffalo wallows” that hold water and have slightly different plant communities.
In the Silveaus Dropseed prairies of Northeast Texas and the Coastal prairies the loamy, low pH alfisol soils are higher in sand content and lower in calcium carbonate. These prairies often contain low, circular mounds called mima or pimple mounds.

Botanist Bill Carr talks about the formation of pimple or mima mounds.

Prairies are not just grass. Many pastures you see generally have been grazed more or less continuously since settlement times. Livestock will eventually graze all but the inedible plants. Fields that have been plowed are usually replanted with a single crop and the prairie soil topography is changed. Pastures were often planted in grasses that have been introduced from other parts of the world, like Johnsongrass, bermudagrass and old-world bluestems . Fields that have been terraced by plows and/or are mainly one species of non-native grass are not native prairies.

Because there are so few native prairie remnants, restoration is a very important part of NPAT’s mission. Visit our Restoration page to learn more.

Lawther-Deer Park Prairie Education Program: Thanks to a generous grant from Shell Oil Company, NPAT has been able to hire a Director of Education to provide prairie programs and activities for school children, teachers and other community groups. Read more.

Texas has many types of prairies and grasslands

Texas was once three-quarters prairie and savanna. The tallgrass coastal prairies and marshes reached many miles inland from the Gulf of Mexico. These can be very wet, and even saline, prairies. The tallgrass prairie extended from southern Canada through Fort Worth-Dallas south to San Antonio. This included Texas’ Blackland Prairie and the Grand Prairie to the west.

The Hill Country of the Edwards Plateau was a mosaic of plant communities, with mixed-grass savanna presumed to have been a large component. The Post Oak Savanna has a prairie understory and an open canopy of post oaks and other trees above.

The Rolling Plains and the High Plains of the Panhandle were mixed-grass and short-grass prairie, and much of West Texas was desert grassland dominated by grama grasses.

Even the Piney Woods of East Texas contain grasslands, often referred to as “pocket prairies.”

Our early Texas wealth, cattle, cotton, and grains, are still based on these now-degraded habitats. The soils they created now feed the world. What we see today is a poor representation of what was. The American prairies are endangered, yet the Endangered Species Act does not protect endangered habitats.