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Text Box: Buffalo Gap National Grassland Grasses

Text Box: The Buffalo Gap National Grassland (BGNG), administered by the USDA, Forest Service, encompasses nearly 600,000 acres located in scattered tracks within southwestern South Dakota. The National Grassland supports a surprising diversity of plants and animals. The predominant vegetative group is, of course, grasses. There is today an enthusiastic groundswell of interest in the grassland ecosystems. Traditionally, nature lovers and outdoor enthusiasts have turned to the mountains and the seashores for relaxation and enjoyment. Like our forbearers on the Oregon trail, most of us have hurried to get across our grasslands as quickly as possible. Grasslands While humid climates support (temperate) forests and dry ones support deserts, grasslands require a moisture level somewhere in between (semi-arid). Moreover, grasslands have a distinctive character. Unlike deserts, the vegetation forms a relatively solid cover over the ground, and unlike forests, the space is open and the view is expansive. Grasslands are one of the most extensive, productive ecosystems in the United States. In spite of the limitations imposed by climate, grasslands present tremendous diversity as they change throughout the seasons and over the years. The existence of the American grasslands is marked by irony. After many millennia of evolution, most tallgrass prairie in private ownership was transformed to croplands within half a century of settlement by the European settlers. Grasslands have not vanished completely. There are approximately 1 million acres of National Grasslands where one can still explore native prairie.

Text Box: Types of Grasslands The largest grassland formation is a huge area covered by tallgrass, mixedgrass, and shortgrass prairie that stretches from the Mississippi River to the Rocky Mountains called the Great Plains. The names of these three grassland types are descriptive: the tallgrass prairie, which requires more moisture than the other two, is dominated by grasses that are over four feet high; the shortgrass prairie, which requires the least moisture, is dominated by grasses that are less than two feet high; the mixedgrass prairie contains a mosaic of grasses, with patches of tallgrass growing in rich, wet soils, and shortgrass covering dry, rocky soils. All grasslands have certain characteristics in common. They generally exist on flat or rolling terrain, and the annual precipitation averages between ten and forty inches. However, quantity alone does not tell the whole story. The time of year when the precipitation falls is also important. On most grasslands stretches of drought occur annually. Moreover, there are great fluctuations from year to year. For example, on the BGNG, peak precipitation occurs during May through July and annual precipitation has varied from seven to twenty-six inches. The average being 15 inches. Because there are few obstacles to air movement, wind is another factor in the climate of grasslands, especially in the Great Plains. As it blows, the wind evaporates water from the soil and plants, thereby accentuating dry conditions.

Text Box: The Grass Plant Of all the plants of the earth, the grasses are of the greatest use to people. Almost all of our food comes from grasses, either directly or indirectly. Many of the important crop plants are grasses: wheat, corn, rice, oats, barley, rye, and sorghum. Meat-producing animals eat crop plants originating from grasses or graze grasses on the open range. Grasses are also used for aesthetic and recreational purposes. As a group, grasses are easy to recognize. However, their lack of brightly colored flowers makes them difficult to distinguish from each other. Many people find grasses confusing and simply take them for granted. Others find them a challenge thus grasses are their favorite plants. Grasses are herbaceous, that is they do not form woody tissue nor do they increase in girth as trees do. Grass flowers are small and inconspicuous, and are arranged either in tight vertical clusters called spikes or in many branched clusters called panicles. Special Adaptations Several characteristics of grasses represent special adaptations to the grassland environment. First, the narrow leaves of grasses, arranged more or less vertically along the stem, present less surface area for evaporation of water and provide for maximum photosynthetic efficiency. Second, a large proportion of grasses’ biomass exists underground in their root systems. The extensive root system presents several advantages. In areas of sparse precipitation, the grass plants establish contact with the deeper, moister layers of soil. In addition, the large root system provides a defense against grazing, mowing, and fire. When a significant portion of the above-ground tissue of a grass plant is removed or destroyed, energy stored in the root system makes new growth possible. Third, perennial grasses’ defense against grazing is a sophisticated process which involves the leaves’ usual growth system. In most plants, the actively growing cells are located at the tips of the leaves. In grasses, however, the growing center is at the base of the leaf, where it joins the stem, and the tip of the leaf is the oldest tissue. Therefore, if the upper portion of the leaves is mowed or grazed, the plant can renew growth from the base.

Text Box: Grass Checklist The BGNG lies within the mixedgrass prairie zone and contains grass species from both the tallgrass and shortgrass communities. Forty-three species of grasses occur regularly within the boundaries of the BGNG. This checklist provides basic information for the most common and easily identified grass species. In addition to grass species. There are several species of sedges that occur from the dry uplands to the wetlands. Sedges are similar in many respects to grasses and are distinguished from grasses by their triangular solid stems. Two sedges found on the BGNG are needleleaf sedge (Carex pensylvanica) and threadleaf sedge (Carex filifolia). For more information go to J.R. Johnsons’ Grassland Plants of South Dakota and Northern Great Plains, which is cited below. The following field guides are available through the Badlands Natural History Association at the National Grasslands Visitor Center in Wall, SD: Brown, L. 1989. Grasslands. The Audubon Society nature guides. Alfred A. Knopf, Inc.: NY, NY 608 pp. Johnson, J.R., and G.E. Larson. 1999. Grassland Plants of South Dakota and Northern Great Plains. SDSU: Brookings, SD. 288 pp. Martin, A.C. 1987. Weeds. Golden Press: NY, NY 169 pp. Van Bruggen, T. 1992. Wildflowers, Grasses and Other plants of the Northern Plains and Black Hills. Fenske Printing, Inc.: Rapid City, SD 112 pp. For further information, contact the USDA, Forest Service offices at the following locations: Wall Ranger District 708 Main Street Wall, SD 57790 (605) 279-2125 www.fs.fed.us/r2/nebraska

Text Box: Fall River Ranger District 1801 Highway 18 Bypass Hot Springs, SD 57747 (605) 745-4107