By Carol Davit, MPF Executive Director
All prairies are grasslands, but not all grasslands are prairies.
In Missouri, grasslands include unplowed, old-growth prairie; glades; savannas; pastures and hay fields of tall fescue (Arundinaria festuca) or other non-native grasses; prairie plantings; and “old fields,” which is a vague but useful term to describe grassy areas that may have been established after forest or woodland was cleared to create pasture, may contain native and non-native plants, and is no longer grazed.
Some species of animals, like many grassland birds, require wide, open grassland spaces; abundant food sources; and vegetative structure appropriate to their life history. Some prefer thicker thatch, like Henslow’s sparrows, whereas others need thinner vegetation, like grasshopper sparrows. Most grassland birds need different kinds of structure at different times of their lives and even in the same day, for instance, sparser areas so morning dew doesn’t soak their chicks, but thicker areas so nests are well hidden.
Unplowed prairie is ideal habitat for many grassland bird species, but many grassland birds also breed in prairie plantings, and even old fields can support specific grassland birds. In fact, several years ago, the site with the highest number of Henslow’s sparrows known in Missouri was MPF’s Bruns Tract, a 160-acre prairie planting. Likewise, many species of mammals, insects, amphibians, reptiles, and plants occur in original, planted, or disturbed native grasslands. They are all “grassland obligates” or “grassland-dependent.”
Other species, however, and often for reasons that are not well understood, are completely dependent on unplowed, old-growth prairie—they are “prairie-obligates,” or almost exclusively so. In Missouri, some examples of prairie-dependent species include grass pink orchids, prairie mole crickets, regal fritillary butterflies, crawfish frogs, and an estimated 190 moth species. In regard to that “almost exclusively so” disclaimer above, in recent years, Missouri Department of Conservation biologists have successfully translocated crawfish frogs from original prairie to a prairie planting, thus expanding their populations. Likewise, habitat for regal fritillaries can be established in Missouri on prairie plantings if their larval host food—species of prairie violets—can be successfully propagated and grown on the plantings. However, there are challenges to violet seed collection and germination, and currently, unplowed, old-growth prairies remain the only viable habitat for regals in Missouri.
If unplowed, old-growth prairies are gone, some grassland species will likely continue to thrive on prairie plantings, but those that are prairie-dependent will disappear. Moreover, even 30 acres of original prairie remnant in Missouri can support more than 300 plant species, including many with high CC values, and thousands of arthropod species depend on that plant diversity, but most prairie plantings (while still extremely important!) contain, at best, dozens of plant species, making them much less biologically diverse and unable to support as great a diversity of arthropods. Original prairies are also critically important seed sources for the native seed industry—so that prairie plantings and prairie gardens can be established.
Pictured above left, the grass pink orchid (Calapogon oklahomensis) is completely prairie dependent. If prairies disappear, so will the grass pink orchid. The black-eyed Susan (Rudbeckia hirta), pictured above right, occurs on unplowed, old-growth prairies and on planted prairies, along roadsides, in old fields, and other disturbed areas. It is grassland-dependent, but not prairie-dependent. Orchid photo by Bruce Schuette. Black-eyed Susan photo by Mervin Wallace.
