Drummond Glacier flats, Banff National Park in 1884 (George Mercer Dawson, Geological Survey of Canada) and in 2007 (Brad White, CW collection).

Remains of several pit houses lie on this windswept shingle flat on the headwaters of the Red Deer River in Alberta. These were likely used by First Nations from the west, largely nourished by salmon, deer, and plants, but who routinely crossed the continental divide to hunt in the valleys and foothills of the eastern slopes for bison– an important source of meat, robes, hides and leather, all valuable for survival and trade. Studies integrating archaeology, anthropology, history and ecology with a wealth of First Nation’s traditional knowledge tell us a fascinating story of  how mountain and prairie ecosystems could have developed over during the last millenia. Repeat photographs help illustrate this lost pattern of regional landscape history. For a quick example from the United States, the historical landscape around Henry’s Lake in Idaho (click link) is a great example of long distance movement of bison herds westwards from the plains.

To download a PDF of a more detailed report on bison movement corridors (click link).  

 

Ancient Corridors Across the Rockies

Consider that the biogeography of northwestern North America was for millennia partially structured by the interaction between species of great abundance: salmon from the Pacific Ocean, and bison from the Great Plains. Humans were the key component linking these great bodies of biomass. Many age-old patterns of human movement for fishing, hunting, gathering, burning and trading were intimately connected to bison and salmon. Through these linkages, people, for the more than ten millennia since deglaciation, helped regulate the patterns and abundance of the great masses of these fish and grazers.

Traditional and current peoples can easily understand the general movement patterns of salmon to and from the Pacific Ocean. The importance of the lakes and streams as nurseries for the young fish, and for the great rivers such as the Fraser and the Columbia, as a route to and from the Pacific Ocean waters is easily comprehended.   How waterfalls and canyons function to restrict salmon movements is obvious. Clearly salmon from the Pacific could not, through the ages, leave streams to walk across the passes through the mountain cordillera that drain to the Atlantic or Arctic. Moreover, people well know the importance of preserving the nursery stocks returning to spawn in the headwater stream gravels. These are the essence of a life cycle that nurtured the valuable fisheries that sustained human cultures. ¹

A more complicated ecological approach is required to fathom the abundance and distribution of the nomadic North American bison in areas along the Rocky Mountains (see Map 1 below). From traditional hunters to modern ecologists, people have found the bison wanderings and habitat use patterns an enigma. Why did bison occupy the Great Plains in the millions, yet were rarely found on the rich Palouse Prairie of Washington? How could bison permeate the woodlands and deep snows to occupy vast areas of the boreal forest northwest of the Great Plains, yet were usually not found on extensive valley bottom grasslands only a short distance into the mountains on the west slopes of the Rocky Mountains at the headwaters Columbia and Fraser rivers?

“Clearly a Long-Established Process”

“It is probable that had the bison remained unmolested by man and uninfluenced by him he would have crossed the Sierra Nevada and the Coast Range and taken his abode in the fertile valleys of the Pacific Slope.”  William T. Hornaday, 1887  ²

Since the time of the “moccasin telegraph”, the density and distribution of bison along its western range limits of bison was a topic of serious human contemplation. While today the discussion of “buffalo” numbers is mostly confined to debates in academic papers or within the confines of government offices, in past times a good understanding of how far the bison moved to the west, or how far hunters would have to travel to the east , often into their neighbor’s territory, was clearly a matter of survival. No animal rivaled the bison as a provider of food, clothing, and shelter. While the record of First Nation’s campfire discussions are mostly lost to us today, the early white travelers in the west faced similar problems on how and where they could procure bison, and their journals of contain numerous records of feast or famine along the western edge of the range. In August 1805 Lewis and Clark were forewarned by the Shoshone of the lack of game to the west of the mountains. Lewis recorded that “They informed me that there was no buffalo on the West side of these mountains; that the game consisted of a few Elk deers and Antelopes, and that the natives subsisted on fish and roots principally.” This proved true, and after the expedition moved into the valleys of the Columbia River, they often subsisted on roots, or the meat from dogs and horses.³

For the next several decades, the journals of fur traders, trappers and other early travelers provide details of where bison were, and where they were not. They describe passes across the mountains that were easily passable to bison, and those where bison were rare or not present. They describe herd sizes, and through their discussion with native Americans with knowledge of the habitat, we are given a reasonable record of the cultural and ecological influences on bison behavior and abundance. Early historians and bio-geographers synthesized these records and put the story together. As we can see from Hornaday’s  explanation above, by 1887 a scientific perspective on the causes of the bison’s range boundaries was developing.  In 1932, historian Ceylon Kingston further compiled these observations. He surmised:

The distribution of the buffalo over the continental area depended on a number of factors. Among these were the normal length of life of the species, and the rate of reproduction; the amount of available food as affected by soil, temperature and rainfall; such major obstacles as mountain chains, dense forests, deep canyons and areas of extreme desert type; predator animals and human enemies. In considering the range of the buffalo the Columbia Basin presents a curious and rather intricate problem and biological distribution in which the hunting by the Indians and physiographic difficulties explain in the most part the scarcity or absence of the buffalo. ⁴

Some two decades later, Frank Gilbert Roe published his seminal work “The North American Buffalo.” In nearly 1000 pages of small-fonted text, he condenses over 4 centuries of observations on bison. Similar to earlier compilations, he explained that:

“Even before the advance of the white men into the Rocky Mountain territory, the westward advance of the buffalo must have been much impeded by the ‘economic pressure’ of the Indian tribes beyond the actual buffalo range. For many Indians journeyed through the passes to procure bison meat and hides, either by hostile forays or by trade. This is attested by the earliest (European) observers and by many others, and was clearly a long-established process.”  ⁵

This is the basic description of an important long-term eco-cultural process, one that is much interest to researchers studying bison ecology today. We can visualize the opposing human versus bison use of these “wildlife corridors” for several networks of passes and trails across the Rocky Mountains as shown in Map 1.

Map 1: Locations of selected Native American groups, potential summer bison density, and the relative importance of several bison and human movement routes across the Rocky Mountains in northwestern North America for the period of approximately 1800 to 1830.  The map shows only one of many potential scenarios for summer conditions of moderate to high densities of mixed male and female herds on the Great Plains. This pattern would change each year as bison followed unique seasonal patterns of forage created by precipitation and burning, and avoided predation by human groups and other carnivores. In general, in late spring bison had moved away from woodlands and out on the open plains. Here they may have been found near sources of water, and avoided human predation by favouring zones between tribes at war.

Current Approaches to Understanding Bison Abundance at its Western Range Limits

Since the latter 1980s, researchers from numerous disciplines have been integrating Kingston’s and Roe’s thinking into the distribution and abundance of bison and other large terrestrial mammals in the Pacific Northwest. Multi-disciplinary ecologists such as Dirk Van Vuren, Charles Kay and others have more fully considered these eco-cultural processes, and some salient points for how they interacted could be as follows:⁶

• Given relatively low numbers of bison west of Rockies, and intense hunting by Native Americans, routine recolonization from bison from the Great Plains might be required to maintain larger western herds such as along the Snake River, or most small herds within the Rocky Mountains ; ⁷
• Large herds of bison moving westwards might be required to “swamp with abundance” groups of human hunters moving eastward to hunt them. This would be most likely to occur in wide gaps such as the South Pass;
• Large herds of bison in or near the passes across the Rockies would most likely be found where Great Plains grasslands most closely approach the mountains such as at the head of the Platte River (South Pass), or along the Missouri River where the Sun River provides access to Lewis and Clark and Cadotte passes. ⁸
• Mountain grasslands and relatively unbroken terrain might be required to facilitate large herds in the mountains, with the dry, windy South Pass area linking the North Platte, Green, and Snake headwaters having the most ideal conditions. Other passes might require very high frequencies of burning to keep them timber free for summer use, and snow depths in winter would limit bison use;
• The number of native peoples travelling eastward to hunt bison could also be important. For example, the presence of bison in the upper Snake River may have reduced the need for human movements across South Pass, whereas high densities of people in the upper Columbia and Fraser watersheds, and a dearth of bison may have favoured high use of passes by people travelling east to hunt to on the Great Plains and eastern foothills and river headwaters;⁹
• Tribal relations might be important influences on bison abundance and movements. Passes that lay within intertribal warfare zones might be less frequently used by hunters, allowing bison numbers to increase in these corridors. For example, Kootenay Plains, on the headwaters of the North Saskatchewan was historically a buffer zone between warring tribes, and was historically a noted location for finding bison in abundance; ¹⁰
• The importance of salmon in supporting complex hunter-gatherer societies west of the continental divide could be of special significance. Supported by dried salmon, these peoples could form dedicated groups of hunters and traders to travel eastwards for long periods of time focused on resources provided by the bison (robes, hide, and meat), and after 1700, also trading horses with plains peoples. ¹¹

Future Research Approaches and the “Bison and Salmon” Theme

In the webpages for the “Bison and Salmon” theme, I will use then and now photographs to more fully the long-term ecological conditions several movement corridors for bison and humans across the Western Cordillera. I describe the changing landscapes visible in these images with research from archaeologists, historians, plant ecologists, and wildlife biologists. Moreover, I use detailed first person journal accounts from early European travelers to describe what they saw, hunted and ate each day as they crossed the Northwest, and what they learned from talking with the Native Americans they met, or who were often guiding their groups. For areas in Canada where pocket gophers and other actions have not greatly altered surface soil profiles, I have also done transects collect data on the abundance of historic bison wallows. These are large (2-6 meter diameter)and deep (.5 to 2 meter) dishes made by the large beasts rolling in the soil that persist across landscapes historically occupied.  Wallow patterns, in combination with historical and archaeological data, helped provide a strong inference on the past presence of bison. I will maintain a downloadable technical report that describes the ongoing results of this analysis of historical bison movement corridors in the Western Cordillera¹²

In assembling these photographs, journal accounts, and doing wallow-counts, I am trying to anticipate how future researchers may further understand the “bison-salmon” link and other interactions. Modern spatial analytical approaches offer a host of options of how to quantify and evaluate the factors listed decades ago by Hornaday, Kingston, Roe and others. For example “friction modelling” can quantify potential routes and rates of animal movements across variable landscapes and seasons, and has been recently been used for bison. ¹³ A host of recent spatially and temporally specific predator-prey analyses including the effects of herd size and habitat type, and potential influences on migratory patterns.¹⁴ Importantly, after several decades where “wilderness and the American mind” seemed to diminish our ability to understand long-term human influences, I think we are again willing to consider the astounding, and complex role our species has in shaping vast ecosystems, not just in the present and future, but also in the past.  This understanding is leading to a whole new body of spatially based research on human-bison interactions ¹⁵

One approach to using these new approaches will be comparative analyses, at a landscape level, of different corridor networks across the Rockies. Using repeat photographs, and several movement movement corridors I will discuss and illustrate with repeat photography of “then and now” conditions are, from south to north (see Map 1):

South Pass– An expansive area of desert, shrubland, and grassland across rolling terrain that links the North Platte, Sweetwater, Green, Bear and Snake River headwaters. This was likely the predominant bison movement route to the western slopes to reach the Snake River. The headwater area had relatively low densities of people due to salmon movements being blocked by Shoshone and Twin falls. This well-used bison travel corridor ultimately became the route for the famed Oregon Trail to the Pacific.¹⁶ A major bison dispersal event over South Pass about 1815 may have resulted in herds of bison reaching as far as Henry’s Lake west of the Yellowstone plateau. ¹⁷

Yellowstone and Missouri Headwaters– An important linkage follows the Yellowstone River westwards from the Great Plains to the headwaters of the Missouri River and then on to northern headwaters tributaries of the Salmon River.  In historic times the Nez Perce followed this route eastwards to hunt bison, and trade horses with Crow. Moreover, the corridor may have created a what some biologists believe was a uniquely numerous bison population for the Rocky Mountains in what is today`s Yellowstone National Park. These bison may have in turn dispersed into the upper Snake River through the Jefferson and Madison watersheds;¹⁸

Blackfoot River “Road to the Bison”- A famed route links the Clark Fork watershed on Montana’s west slopes to the Sun River, which joins the Missouri River. This is a significant corridor because over a relatively short distance (less than 50km) it joins an area of known high bison numbers well-described by Lewis and Clark near Great Falls to expansive grasslands on the western slopes along the Blackfoot River.¹⁹

Kootenay Passes– A series of low notches in the Rocky Mountains provide a linkage between the headwaters of the Flathead and Oldman rivers (a main tributary of the South Saskatchewan).  When the western tribes obtained the horse this route provided a direct route for major incursions to hunt bison in the eastern foothills, plains and parklands. Similarly, it is possible that bison could have easily moved westwards across the Kootenay Passes to expansive grasslands along the Flathead River;²⁰

Shuswap (Simpson) and Whiteman Passes to the Bow River– Several passes cross the Rockies near the headwaters of the Bow River, linking Ktunaxa, Secwepemc, and Sin`ixt  peoples living in  the upper Kootenay and Columbia watersheds to important bison habitat on the headwaters of the Highwood, Bow and Red Deer rivers.²¹

Howse Pass to the Kootenay Plains- A single low pass links the upper Columbia River to the North Saskatchewan River. This was the northernmost of routes used by the K’tunaxa (Kootenai) peoples to cross the Rockies, and was likely more routinely traversed by the Secwepemc. The Kootenay Plains along the North Saskatchewan held relatively high bison numbers. In 1808, David Thompson followed a small group of bison westwards across Howse Pass.²²

Athabasca Pass- A historic route links the high First Nation human populations found near today`s city of Kamloops to the Athabasca River near the today Jasper via the Shuswap Lakes and the “Big Bend`of the Columbia River. After 1810, the eastern part of this corridor became the main route for the fur trade`s express brigades, and bison were observed as far west as Prairie de la Vache on the upper Athabasca River.²³

Peace River “Rocky Mountain Pass”- The northernmost movement corridor I will evaluate is a route between people occupying the rich salmon fishery on the northern headwater tributaries of the Fraser River (Nechaco and Stuart rivers)  the and an area of high bison abundance along the Peace River on the eastern slopes of the Rocky Mountains. Historically the need for fat and leather encouraged human travel between these two areas, although bison movements might have been limited.²⁴

For each of these bison-human corridors, I use “then and now” photographs moving from west to east to describe historical records of human use and bison movements, bison wallow abundance, condition of the vegetation, and how this may have changed from past times. I often take an expansive view, starting with regions well to the west of the actual passes across the Rockies where eco-cultural processes might drive human movements to the prairies. Similarly, on the Great Plains east of the corridors, I also re-photographed areas far to the east to help consider human and bison interactions that might influence corridor use.

As they are posted, please enjoy the then and now views, and the supporting discussion that describes a fascinating eco-cultural process that dominated the biogeography of the Pacific Northwest for thousands of years.

Footnotes