An Introduction to Grasslands

Grasslands are open landscapes where the dominant forms of vegetation are grasses, grass-like plants, and forbs. There may be trees present, but in scarce quantities. They support a highly biodiverse community of plant and animal species, which are adapted to disturbances in the system. Common forms of disturbance in grasslands include fire and grazing.

Grasslands are distributed all across the world in areas with specific climates and geologic history that contributed to their formation. These regions tend to not be too wet, nor too dry to support grassy and herbaceous species, but not larger woody vegetation like trees. Several examples of grasslands ecosystems are included on the map below, but many more are sprinkled throughout the world.

There are several different types of grasslands, including prairies, pampas, steppes, and savannahs. Not included are: overgrown lawns, maintained sports fields or lawns, or crop fields.

Historically, fire has been a natural part of grassland ecosystems. As leaf litter accumulated and dried out, lightning strikes could easily start fires that moved over a large portion of the landscape before burning out. Today, fire suppression is an issue that leads to increased fuel loads that may cause more intense wildfires.

The benefits from fires include reduced competition from woody plants, increased habitat variety, and an increase in palatable forage for grazing animals. Because most herbaceous species have a high proportion of biomass belowground, grassland plants more easily reestablish post-fire when compared to trees or shrubs. The tender, green new growth following a fire is preferable to grazers, who may then continue to maintain the low thatch. The differences in the burned versus not burned areas also serve to provide habitat to a wider variety of animal species whose needs may vary depending on their life history.

Grazing animals are present in grasslands across the globe from zebras, giraffes, and elephants in African savannas to cattle and bison in the North American plains. While many of the bison have been replaced on the plains by cattle, whose grazing habits and preferences differ, they can still be useful in ecosystem maintenance. Grazers can contribute to a patchy, mosaic landscape of vegetation, similarly to fire, which increases the suitability of the ecosystem to provide habitat to more species.

Grasslands tend to be species rich ecosystems that support high levels of biodiversity. Whether for permanent residents or migratory animals, grasslands have plenty of niches to fill thanks to disturbance. Plant diversity remains important to grassland ecosystem health as well, with increased species being attributed to higher stability.

A handful of examples of different species that might inhabit a grassland include: black-footed ferrets, buffalo grass, bison, goldenrod, northern bobwhites, Henslow's sparrows, asters, greater kudu, prairie dogs, blue grama grass, zebra, and red oat grass, among many others.