Date of this Version
Areas of eight habitats were identified, delineated, and measured along the unchannelized Missouri River in South Dakota. Agricultural and urban developments existed on 60 percent of the land within 1 km of the river. Six habitat types made up the non-developed land in the study area: cottonwood-dogwood (16 percent), cottonwood-willow (9 percent), elm-oak (7 percent), cattail marsh (3 percent), sand dune (3 percent), and sand bar (1 percent). All non-developed habitats except sand bar were sampled to obtain vegetative composition and to determine their value to wildlife. The value of each habitat to nine faunal groups of wildlife was subjectively rated from 0 (poor) to 10 (excellent). An interspersion value was added to arrive at total habitat value.
Cattail marshes were typically monospecific stands of narrow-leaved cattail (Typha angustifolia) in slow-moving, shallow water. This habitat was rated highest in its value to wildlife (8.9), and was especially important for aquatic furbearers, waterfowl, other water and marsh birds, and herptiles.
Cottonwood-dogwood habitat generally consisted of three layers of vegetation: eastern cottonwood (Populus deltoides), red-osier dogwood (Cornus stoloifera), and poison ivy (Toxicodendron rydbergii). A rating of 7.9 was given this habitat, and conditions were good for all terrestrial faunal groups except herptiles.
Cottonwood-willow stands were dominated by eastern cottonwood and various willows (Salix spp.) and occurred in a clumped distribution. Woody vegetation was interspersed with open areas covered with grasses, forbs, sedges (Carex spp.), or horsetail (Eguisetum spp.), forming a system of edges. The total habitat value for cottonwood-willow communities was 7.5; big game and upland game birds found conditions excellent there.
Elm-oak habitat was comprised of a wide variety of trees; the most important were slippery elm (Ulmus rubra), bur oak (Quercus macrocarpa), box elder (Acer negundo), and eastern red cedar (Juniperus virginiana). Grazing of the understory and ground cover reduced the value of this habitat to most types of wildlife (6.7).
Sand dunes were deposited by floods occurring prior to the closure of Fort Randall Dam and Lewis and Clark Dam. Vegetation consisted of older cottonwoods probably existing prior to the floods and younger cottonwood/willow stands, interspersed with bare sand and patches of alfalfa. Conditions were fair for most species of wildlife (5.3), with terrestrial birds and herptiles receiving the most benefit.
Future alterations of the unchannelized river in the study area should be planned with an objective of leaving areas of all six habitats on non-developed land to maintain the diversity of wildlife presently found there.