Lewis & Clark in the Gallatin Valley: the Land we Live on
"while wateing for the canoes to arrive I killed an otter which sunk to the bottom on being shot, a circumstance unususal with that anamal. The water was about 8 feet deep yet so clear that I could see it at the bottom; I swam in an obtained it by diving." [Meriwether Lewis July 22, 1805]
Such did Meriweather Lewis comment on the water quality of the Missouri River (and his tenacity in obtaining an otter hide) a short way downstream from the headwaters of the Missouri. No longer were the members of the expedition dealing with a silt-laden stream with crumbling banks. They had left the Plains and were hauling their canoes into the Rocky Mountains.
The Journals of the Lewis & Clark expedition give us insight into the experiences of the members, but they also reveal how the landscape has changed since their passage. At times, the authors, particularly Meriweather Lewis, provide their own insight regarding the ecological relationship between wildlife and environment. Again, from the region of the Missouri headwaters:
"we saw many beaver and otter today: the former dam up the small channels of the river between the islands and compel the river in these parts to make other channels; which as soon as it has effected that which was stoped by the beaver becomes dry and is filled up with mud sand gravel and driftwood. the beaver is then compelled to seek another spot for his habitation wher[e] he again erects his dam. thus the river in many places among the clusters of islands is constantly changing the direction of such sluices as the beaver are capable of stoping or of 20yds. in width. this anamal in that way I beleive to be very instrumental in adding to the number of islands with which we find the river crouded."
Lewis is attributing the creation of islands to the beaver. In turn, the creation of ponds and islands would have created more shoreline habitat. These shorelines, depending upon age, might be composed of anything from bare soil or cobble to dense willow and shrub thickets, or even stands of cottonwood.
For anyone who has lived upon the arid Great Plains, it's easy to recognize these streamside, or "riparian", plant communities as some of our most productive and diverse wildlife habitats. Beaver, mink, river otter, mule, white-tailed deer, elk, eagle, crane, heron, and an array of other birds are routinely mentioned by Lewis & Clark in the headwaters region. Indeed, they even mentioned the presence of the grizzly or "white" bear and the "panther." By increasing the amount of shoreline, the beaver would have contributed to the amount of habitat available for themselves as well as all these other species.
Essentially, the beaver creates flooded areas. The flooding is essential to germination and survival of willow, cottonwood, and an array of berry producing shrubs. Further downstream from the Headwaters region, the Missouri River is too large for a beaver to dam even a portion of its flow, and as a result, many of them burrow into banks as opposed to construction of a lodge. But at the head of the Missouri, the three rivers of which it is composed have lower volume flows, and are more suitable for damming by this intrepid engineer. While not explicitly stated, it is implied that the members of the expedition encountered more beaver in the Headwaters region than anywhere else along its entire length. On both the upstream and downstream journeys both Lewis and Clark continually comment on the "emence quantity of beaver." Indeed, this is the probable reason that so many fur-trapping expeditions focused on the Three Forks area in subsequent years. This is the reason George Droulliard and John Potts, former members of the expedition, risked, and lost, their lives to the Blackfeet at the Headwaters.
If we apply these considerations to the landscape of today, consider how regulated the Missouri River flow is throughout its length. There are seven dams on the Missouri in Montana alone, and 47 throughout its length. The result is that a tremendous amount of habitat has "gone under," as many old trappers would say.
But the Madison, Gallatin, and Jefferson still routinely flood. In fact, the Gallatin and Jefferson have no impounding structures of any kind. High flows still move soil, scour new channels alongside old beaver dams, and submerge islands and terraces. As a result, while we no longer allow the "grisley bear" [Lewis] to live here, we still have healthy populations of riparian species, including beaver.
Today, if you want to see the big game that the Corp of Discovery experienced, there is no place better than Yellowstone National Park. Nowhere else can you see bison, elk, pronghorn, bears, and wolves interacting upon the landscape. But if you want to experience the river wildlife of Lewis and Clark, grab your driftboat, canoe, or inner tube, and head to the Headwaters. You'll be flowing along a path of riparian wildlife diversity.
[Note: all quotes are from Lewis and Clark in the Three Rivers Valleys, edited by Don Nell and John E. Taylor.]