An ancient mammalian road network once crisscrossed the northern reaches of what is now the United States. Its trails had existed since the last ice age. For thousands of years, large mammals—such as the wooly mammoth, saber-toothed tiger, sloth, bison antiques and later bison bison, cut pathways across the land. Over the years the mammal trails became deeper and wider from the incessant pounding of hooves. Even before humans arrived on the continent, bison, deer and elk located the routes of least resistance through the landscape. After the peopling of North America, humans adopted those same roads for their own use.
The majority of the mammal trails traversed river and stream valleys. Within the Missouri basin, deep, wide roads lay along both sides of the Missouri and Yellowstone rivers. Smaller roads tore up the valleys of the Big Sioux, James and Niobrara. Still smaller traces trekked up creek beds such as Perry Creek (at modern-day Sioux City, Iowa), Bazille Creek and Ponca Creek (in today’s northeast Nebraska) and Okoboji Creek (in present-day central South Dakota).
By the time of the Lewis and Clark Expedition, the road network had become well established and extensive. Sgt. Patrick Gass of the expedition, who took on the duties and responsibilities of the deceased Sgt. Charles Floyd in August 1804, recounted the presence of bison roads in the prairie region. He remarked, “There are … roads and paths made by the buffaloe [sic] and other animals; some of the buffaloe [sic] roads are at least ten feet wide.” John Bradbury, who floated up the Missouri on a keelboat in 1811, noted the presence of a bison route near the mouth of the Niobrara River. He stated, “…we observed excellent roads made by the buffaloes. These roads, I had frequent opportunities … [of] examining, and am of the opinion that no engineer could have laid them out more judiciously.” Edward Harris, the companion of John James Audubon on their 1843 Missouri River journey, remarked, “You would be surprised to see how the whole country here is trodden up by the feet of the Buffalo, and we see their deeply worn paths in all directions, they are now shedding their coats which they leave on every bush.” Bison roads did not cut across the land in a haphazard, indiscernible pattern. Rather, the roads went in specific directions, connecting the region’s oases with one another.
Biological diversity was not dispersed evenly throughout the Missouri Valley, prairie region or northern plains. Instead, flora and fauna concentrated in what 19th-century European-American chroniclers referred to as “bottoms.” The wide bottomlands that stretched all the way across the Missouri’s valley floor were not the same as bottoms.
Bottomlands lay in the lowlands next to the river. Because the bottomlands were subject to annual inundation, the habitat there changed frequently. It could morph from a timber tract to a sand flat in one season. Bottomlands might contain a variety of habitat types, including wetlands, sand dunes, oxbow lakes or acre upon acre of tall big bluestem grass. On the other hand, the bottoms possessed certain characteristics that distinguished them from the bottomlands.
Bottoms sat on top of the second or third terrace above the Missouri or its tributaries. Consequently, bottoms remained immune to the river’s annual floods. Distance from the rising waters of the Missouri meant that the habitat types within bottoms became more stable over time. Trees had time to take root and grow, so bottoms included healthy stands of ash, oak and hickory. Rich soils existed in the bottoms—the result of the decomposition of organic matter, the defecating of bison and the infrequent deposition of Missouri River silt. Such soils fostered the growth of tall prairie grasses, chokecherry bushes and mulberry trees. The wealth of edible vegetation in turn attracted bears, whitetail deer, elk and bison, which led to the continued fertilization of the soil.
The majority of bottoms existed just downstream from the mouths of the Missouri’s tributaries. A long, bountiful bottom once reached from today’s Blair, Neb., to Homer, Neb. Frontiersmen knew this stretch of land as “The 60-Mile Bottom.” A small bottom existed between the mouth of Perry Creek and the mouth of the Floyd River (where today’s Sioux City now stands). Cottonwood trees grew on the fringes of those two waterways, while the flat in between the streams grew wild flowers and big bluestem. Another bottom could be found east of the mouth of the Big Sioux River beneath towering Loess Hills. Because the land within this bottom rarely sank under the flooding Missouri or Big Sioux rivers, it held thick, old oak trees at the time of European-American settlement.
On the south side of the mouth of the Vermillion River, in present-day southeast South Dakota, could be found another bottom. In 1833 Prince Maximilian of Wied remarked on this ecological sanctuary. He wrote, “We continued our voyage, but soon lay to at the prairie, on the right bank, because Mr. McKenzie wished to form a plantation at this place. The whole plain [or bottom] was covered with high, dry grass. On the bank of the river there was a fine border of tall timber trees, in which the turtle-dove cooed… At the spot where we now were, it is said that large herds of buffaloes are seen in the winter.”
Along the south bank of the James River where it joined the Missouri, a bottom with lofty groves of cottonwood trees spread out. Another bottom blanketed the Missouri Valley just below the mouth of the Niobrara (where the town of Niobrara, Neb., once stood). Prince Wilhelm, a member of the German royalty, viewed the Niobrara bottom in 1823. He recalled, “The southern bank near the mouth of the [Niobrara] stream expands into a beautiful prairie region with tall grass.” The valley contained additional bottoms further north.
The bottoms represented oases or pockets of fertility in an occasionally stingy land. When drought struck the semiarid grassland of the northern plains and shrank the available forage, bison, deer and elk trekked into the bottoms to find fodder. During cold and snow-filled winters, those same animals found shelter in the bottoms amongst the trees and high grass. Bottoms enabled the valley’s creatures to survive during inclement weather and periods of extended drought or cold. During the era of European- American agricultural settlement, farmers occupied the bottoms—converting habitat to cropland. The bottoms also became disconnected from one another as roads, fences, towns and farms disrupted animal migratory routes.
Since the 1990s, the Army Corps of Engineers, in cooperation with the U.S. Fish and Wildlife Service and state conservation agencies, has been working to restore the Missouri River ecosystem. Much of the rehabilitation effort has involved the reopening of the Missouri’s former side channels, the re-creation of sandbar habitat and the formation of wetlands adjacent to the big river. In the wake of this year’s flood, that restoration work has come under fire from Missouri Valley farmers and their congressional representatives. But the critics of ecosystem recovery need to understand that river restoration contributes to flood control. The widening out of the Missouri’s channel area, the reconnecting of the main channel to side channels and the creation of wetland habitat in the valley bottomlands will diminish future flood heights and decrease the velocity of floodwaters—which will lessen damage to agricultural land in the valley. The reestablishment of riparian habitat will provide numerous ecological, economic and social benefits.
But it should be noted that the recovery of the Missouri River ecosystem requires more than opening former side channels or re-creating widely separated wetlands. A healthy, self-sustaining ecosystem will necessitate the reestablishment of some of the former bottoms as oases. Those refuges will then need to be coupled to the ancient mammalian road network. If this is not done, and restored habitat remains isolated in small, disconnected patches, ecosystem restoration will be slowed or stopped altogether. Without continuous stretches of habitat and the ability to move freely between regions, species will continue to suffer higher incidences of predation and human interference—which will increase species mortality rates. We need to think of Missouri River recovery on a larger, regional scale.